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Ravaszová S, Dvořák K, Boháč M, Všianský D, Jančíková A. Formation, Stability, and Crystallinity of Various Tricalcium Aluminate Polymorphs. Materials (Basel) 2024; 17:735. [PMID: 38591982 PMCID: PMC10856400 DOI: 10.3390/ma17030735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/12/2024] [Accepted: 01/31/2024] [Indexed: 04/10/2024]
Abstract
Tricalcium aluminate is an important phase of Portland clinker. In this paper, three polymorphs of C3A were prepared by means of the solid-state synthesis method using intensive milling of the raw material mixture which was doped with various amounts of Na2O and sintered at a temperature of 1300 °C for 2 h. The final products were evaluated through X-ray diffraction using Rietveld analysis. The effect of the Na dopant content on the change in the crystalline structure of tricalcium aluminate was studied. It was proven that the given preparation procedure, which differed from other studies, was close to the real conditions of the formation of Portland clinker, and it was possible to prepare a mixture of different polymorphs of calcium aluminate. Fundamental changes in the crystal structure occurred in the range of 3-4% Na, when the cubic structure changes to orthorhombic. At a dosage of Na dopant above 4%, the orthorhombic structure changes to a monoclinic structure. There are no clearly defined boundaries for the existence of individual C3A phases; these phases arise at the same time and overlap each other in the areas of their formation at different Na doses.
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Affiliation(s)
- Simona Ravaszová
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (S.R.); (A.J.)
| | - Karel Dvořák
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (S.R.); (A.J.)
| | - Martin Boháč
- Research Institute for Building Materials, Hněvkovského 30/65, 617 00 Brno, Czech Republic;
| | - Dalibor Všianský
- Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic;
| | - Andrea Jančíková
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (S.R.); (A.J.)
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2
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Gubicza J, Mukhtarova K, Kawasaki M. Nanostructuring of Additively Manufactured 316L Stainless Steel Using High-Pressure Torsion Technique: An X-ray Line Profile Analysis Study. Materials (Basel) 2024; 17:454. [PMID: 38255622 PMCID: PMC10820489 DOI: 10.3390/ma17020454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/07/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024]
Abstract
Experiments were conducted to reveal the nanostructure evolution in additively manufactured (AMed) 316L stainless steel due to severe plastic deformation (SPD). SPD-processing was carried out using the high-pressure torsion (HPT) technique. HPT was performed on four different states of 316L: the as-built material and specimens heat-treated at 400, 800 and 1100 °C after AM-processing. The motivation for the extension of this research to the annealed states is that heat treatment is a usual step after 3D printing in order to reduce the internal stresses formed during AM-processing. The nanostructure was studied by X-ray line profile analysis (XLPA), which was completed by crystallographic texture measurements. It was found that the as-built 316L sample contained a considerable density of dislocations (1015 m-2), which decreased to about half the original density due to the heat treatments at 800 and 1100 °C. The hardness varied accordingly during annealing. Despite this difference caused by annealing, HPT processing led to a similar evolution of the microstructure by increasing the strain for the samples with and without annealing. The saturation values of the crystallite size, dislocation density and twin fault probability were about 20 nm, 3 × 1016 m-2 and 3%, respectively, while the maximum achievable hardness was ~6000 MPa. The initial <100> and <110> textures for the as-built and the annealed samples were changed to <111> due to HPT processing.
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Affiliation(s)
- Jenő Gubicza
- Department of Materials Physics, Eötvös Loránd University, 1117 Budapest, Hungary;
| | - Kamilla Mukhtarova
- Department of Materials Physics, Eötvös Loránd University, 1117 Budapest, Hungary;
| | - Megumi Kawasaki
- School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, OR 97331-6001, USA;
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Gasha SB, Trautmann M, Wagner G. Effect of Milling Time and Reinforcement Volume Fraction on Microstructure and Mechanical Properties of SiC p-Reinforced AA2017 Composite Powder Produced by High-Energy Ball Milling. Materials (Basel) 2024; 17:435. [PMID: 38255603 PMCID: PMC10821172 DOI: 10.3390/ma17020435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024]
Abstract
The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles.
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Affiliation(s)
- Shimelis Bihon Gasha
- Professorship of Composites and Material Compounds, Institute of Materials Science and Engineering (IWW), Chemnitz University of Technology, 09125 Chemnitz, Germany; (M.T.); (G.W.)
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Beera CS, Dhanalakshmi B, Devi DN, Vijayalakshmi D, Mishra A, Ramesh S, Rao BP, Shyamala P, Menelaou M, Alanazi N, Alodhayb AN. Magnetic and Magnetostrictive Properties of Sol-Gel-Synthesized Chromium-Substituted Cobalt Ferrite. Gels 2023; 9:873. [PMID: 37998963 PMCID: PMC10671203 DOI: 10.3390/gels9110873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/25/2023] Open
Abstract
Chromium (Cr)-doped cobalt ferrite nanoparticles were synthesized using a sol-gel autocombustion method, with the chemical formula CoCrxFe2xO4. The value of x ranged from 0.00 to 0.5 in 0.1 increments. X-ray diffraction analysis confirmed the development of highly crystalline cubic spinel structures for all samples, with an average crystallite size of approximately 40 to 45 nm determined using the Scherrer equation. Pellets were prepared using a traditional ceramic method. The magnetic and magnetostrictive properties of the samples were tested using strain gauge and VSM (vibrating sample magnetometer) techniques. The results of the magnetic and magnetostrictive tests showed that the chromium-substituted cobalt ferrites exhibited higher strain derivative magnitudes than pure cobalt ferrite. These findings indicated that the introduction of chromium into the cobalt ferrite structure led to changes in the material's magnetic properties. These changes were attributed to anisotropic contributions, resulting from an increased presence of Co2+ ions at B-sites due to the chromium substitutions. In summary, this study concluded that introducing chromium into the cobalt ferrite structure caused alterations in the material's magnetic properties, which were explained by changes in the cationic arrangement within the crystal lattice. This study successfully explained these alterations using magnetization and coercivity data and the probable cationic dispersion.
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Affiliation(s)
- Chandra Sekhar Beera
- Vignan’s Institute of Engineering for Women (Autonomous), Visakhapatnam 530046, AP, India
| | - B. Dhanalakshmi
- Vignan’s Institute of Information Technology (VIIT-A), Visakhapatnam 530049, AP, India
| | - D. Nirmala Devi
- Vignan’s Institute of Engineering for Women (Autonomous), Visakhapatnam 530046, AP, India
| | - D. Vijayalakshmi
- Vignan’s Institute of Engineering for Women (Autonomous), Visakhapatnam 530046, AP, India
| | - Akanksha Mishra
- Vignan’s Institute of Engineering for Women (Autonomous), Visakhapatnam 530046, AP, India
| | - S. Ramesh
- Department of Physics, GSS, GITAM Deemed to be University, Visakhapatnam 530045, AP, India
| | | | - P. Shyamala
- Department of Chemistry, Andhra University, Visakhapatnam 530003, AP, India;
| | - Melita Menelaou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Arch. Kyprianos Str., Limassol 3036, Cyprus;
| | - Nadyah Alanazi
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Abdullah N. Alodhayb
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia;
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Huang H, Zhang Y, Liu Y, Guo Y, Hu C. Influence of Intermolecular Interactions on Crystallite Size in Crystalline Solid Dispersions. Pharmaceutics 2023; 15:2493. [PMID: 37896253 PMCID: PMC10610461 DOI: 10.3390/pharmaceutics15102493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
Crystalline solid dispersions (CSDs) represent a thermodynamically stable system capable of effectively reducing the crystallite size of drugs, thereby enhancing their solubility and bioavailability. This study uses flavonoid drugs with the same core structures but varying numbers of hydroxyl groups as model drugs and poloxamer 188 as a carrier to explore the intrinsic relationships between drug-polymer interactions, crystallite size, and in vitro dissolution behavior in CSDs. Initially, we investigate the interactions between flavonoid drugs and P188 by calculating Hansen solubility parameters, determination of Flory-Huggins interaction parameters, and other methods. Subsequently, we explore the crystallization kinetics of flavonoid drugs and P188 in CSD systems using polarized optical microscopy and powder X-ray diffraction. We monitor the domain size and crystallite size of flavonoids in CSDs through powder X-ray diffraction and a laser-particle-size analyzer. Finally, we validate the relationship between crystallite size and in vitro dissolution behavior through powder dissolution. The results demonstrate that, as the number of hydroxyl groups increases, the interactions between drugs and polymers become stronger, making drug crystallization in the CSD system less likely. Consequently, reductions in crystalline domain size and crystallite size become more pronounced, leading to a more significant enhancement in drug dissolution.
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Affiliation(s)
- Hua Huang
- Medical College, Qinghai University, Xining 810001, China; (H.H.); (Y.Z.); (Y.L.); (Y.G.)
| | - Yong Zhang
- Medical College, Qinghai University, Xining 810001, China; (H.H.); (Y.Z.); (Y.L.); (Y.G.)
| | - Yao Liu
- Medical College, Qinghai University, Xining 810001, China; (H.H.); (Y.Z.); (Y.L.); (Y.G.)
| | - Yufei Guo
- Medical College, Qinghai University, Xining 810001, China; (H.H.); (Y.Z.); (Y.L.); (Y.G.)
| | - Chunhui Hu
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810001, China
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Yang W, Jo SH, Tang Y, Park J, Ji SG, Cho SH, Hong Y, Kim DH, Park J, Yoon E, Zhou H, Woo SJ, Kim H, Yun HJ, Lee YS, Kim JY, Hu B, Lee TW. Overcoming Charge Confinement in Perovskite Nanocrystal Solar Cells. Adv Mater 2023; 35:e2304533. [PMID: 37390092 DOI: 10.1002/adma.202304533] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/02/2023]
Abstract
The small nanoparticle size and long-chain ligands in colloidal metal halide perovskite quantum dots (PeQDs) cause charge confinement, which impedes exciton dissociation and carrier extraction in PeQD solar cells, so they have low short-circuit current density Jsc , which impedes further increases in their power conversion efficiency (PCE). Here, a re-assembling process (RP) is developed for perovskite nanocrystalline (PeNC) films made of colloidal perovskite nanocrystals to increase Jsc in PeNC solar cells. The RP of PeNC films increases their crystallite size and eliminates long-chain ligands, and thereby overcomes the charge confinement in PeNC films. These changes facilitate exciton dissociation and increase carrier extraction in PeNC solar cells. By use of this method, the gradient-bandgap PeNC solar cells achieve a Jsc = 19.30 mA cm-2 without compromising the photovoltage, and yield a high PCE of 16.46% with negligible hysteresis and good stability. This work provides a new strategy to process PeNC films and pave the way for high performance PeNC optoelectronic devices.
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Affiliation(s)
- Wenqiang Yang
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seung-Hyeon Jo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yipeng Tang
- Department of Materials Science and Engineering, University of Tennessee, 1001-1099 Estabrook Rd, Knoxville, TN, 37996, USA
| | - Jumi Park
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemoon-gu, Seoul, 03722, Republic of Korea
| | - Su Geun Ji
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seong Ho Cho
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yongseok Hong
- Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemoon-gu, Seoul, 03722, Republic of Korea
| | - Dong-Hyeok Kim
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jinwoo Park
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Eojin Yoon
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Huanyu Zhou
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Seung-Je Woo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Hyeran Kim
- Advanced Nano Research Group, Korea Basic Science Institute (KBSI), 169-148 Gwahak-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea
| | - Hyung Joong Yun
- Advanced Nano Research Group, Korea Basic Science Institute (KBSI), 169-148 Gwahak-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea
| | - Yun Seog Lee
- Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jin Young Kim
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Bin Hu
- Department of Materials Science and Engineering, University of Tennessee, 1001-1099 Estabrook Rd, Knoxville, TN, 37996, USA
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- SN Display Co. Ltd., 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Institute of Engineering Research, Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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Miao B, Zhang J, Guo J, Ma X, Wang L, Zhang X. Understanding the Microstructure Evolution of 8Cr4Mo4V Steel under High-Dose-Rate Ion Implantation. Materials (Basel) 2023; 16:5876. [PMID: 37687568 PMCID: PMC10488348 DOI: 10.3390/ma16175876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/09/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023]
Abstract
In this study, the effect of microstructure under various dose rates of plasma immersion ion implantation on 8Cr4Mo4V steel has been investigated for crystallite size, lattice strain and dislocation density. The phase composition and structure parameters including crystallite size, dislocation density and lattice strain have been investigated by X-ray diffraction (XRD) measurements and determined from Scherrer's equation and three different Williamson-Hall (W-H) methods. The obtained results reveal that a refined crystallite size, enlarged microstrain and increased dislocation density can be obtained for the 8Cr4Mo4V steel treated by different dose rates of ion implantation. Compared to the crystallite size (15.95 nm), microstrain (5.69 × 10-3) and dislocation density (8.48 × 1015) of the dose rate of 2.60 × 1017 ions/cm2·h, the finest grain size, the largest microstrain and the highest dislocation density of implanted samples can be achieved when the dose rate rises to 5.18 × 1017 ions/cm2·h, the effect of refining is 26.13%, and the increment of microstrain and dislocation density are 26.3% and 45.6%, respectively. Moreover, the Williamson-Hall plots are fitted linearly by taking βcosθ along the y-axis and 4sinθ or 4sinθ/Yhkl or 4sinθ(2/Yhkl)1/2 along the x-axis. In all of the W-H graphs, it can be observed that some of the implanted samples present a negative and a positive slope; a negative and a positive slope in the plot indicate the presence of compressive and tensile strain in the material.
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Affiliation(s)
- Bin Miao
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; (J.Z.); (J.G.)
| | - Jinming Zhang
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; (J.Z.); (J.G.)
- CETC Academy of Chips Technology, Chongqing 401332, China
| | - Jiaxu Guo
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; (J.Z.); (J.G.)
| | - Xinxin Ma
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; (J.Z.); (J.G.)
| | - Liqin Wang
- MIIT Key Laboratory of Aerospace Bearing Technology and Equipment, Harbin Institute of Technology, Harbin 150001, China;
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Gomez-Vazquez OM, Bernal-Alvarez LR, Velasquez-Miranda JI, Rodriguez-Garcia ME. Effects of Temperature on the Physicochemical Properties of Bioinspired, Synthetic, and Biogenic Hydroxyapatites Calcinated under the Same Thermal Conditions. Nanomaterials (Basel) 2023; 13:2385. [PMID: 37686893 PMCID: PMC10490284 DOI: 10.3390/nano13172385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/04/2023] [Accepted: 08/12/2023] [Indexed: 09/10/2023]
Abstract
The paper studies the changes in physicochemical properties of three types of hydroxyapatite (HAp): HAp-HB (from bovine sources), HAp-SC (chemically synthesized), and bioinspired HAp-SE (synthesized using eggshells) calcined under identical thermally controlled conditions from room temperature to 400, 500, 600, 650, 680, 700, 720, 750, 800, and 900 °C in furnace air. The thermogravimetric analysis (TGA) indicated distinct thermal transitions and coalescence phenomena at different temperatures for these samples due to their sources and mineral composition differences. Inductively coupled plasma (ICP) showed that HAp-H (human), HAp-HB (bovine), and HAp-SE (bioinspired) have similar Ca, P, and Mg contents. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the coalescence phenomena increased in the crystallite size as the temperature increased. X-Ray diffraction (XRD) patterns revealed partial phase changes in the bioinspired sample (HAp-SE) and crystallite growth in all samples, resulting in full width at the half maximum (FWHM) and peak position alterations. Fourier-transform infrared spectroscopy (FTIR) showed that HAp-SE exhibited a partial phase change due to dehydroxylation and the presence of functional groups (PO43-, OH, and CO32-) with varying vibrational modes influenced by the obtained method and calcination temperature. Raman spectra of the HAp-SE samples exhibited fluorescence at 400 °C and revealed vibrational modes of surface P-O. It observed the bands of the internal phosphates of the crystal lattice and shifts in the band positions at higher temperatures indicated phosphorus interacting with carbon and oxygen, triggering dehydroxylation.
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Affiliation(s)
- Omar M. Gomez-Vazquez
- Posgrado en Ciencia e Ingeniería de Materiales, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Qro., Mexico;
| | - Leon R. Bernal-Alvarez
- Posgrado en Ciencia e Ingeniería de Materiales, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Qro., Mexico;
| | - Jesus I. Velasquez-Miranda
- Instituto Tecnológico Nacional de México Campus San José Iturbide, Buenavista 3ra. Secc, San José Iturbide 37980, Gto., Mexico;
| | - Mario E. Rodriguez-Garcia
- Departamento de Nanotecnología, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Qro., Mexico;
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EMİL-KAYA E, EVREN B, ERDÖL Z, EKİNCİ D, İPEKOĞLU M, ÖZENLER S. Morphological, microstructural and photocatalytic characterization of undoped and Ni, Co doped Fe 2O 3 particles synthesized by sonochemical method. Turk J Chem 2022; 46:1897-1908. [PMID: 37621333 PMCID: PMC10446927 DOI: 10.55730/1300-0527.3489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/19/2022] [Accepted: 08/02/2022] [Indexed: 12/24/2022] Open
Abstract
In this study, an abundant and eco-friendly photocatalytic material, Fe2O3 particles were synthesized by sonochemical method. Morphological and microstructural investigations of synthesized undoped and Ni, Co-doped Fe2O3 particles were performed. The effect of particle morphology and microstructure on its photocatalytic performance was further investigated. Comparative studies for evaluating particle crystallite sizes were conducted by Williamson-Hall (W-H) method and modified Debye-Scherrer (MDS). Crystallite sizes and lattice strains of Fe2O3 induced by process parameters were calculated by W-H method based on uniform deformation model (UDM). The crystallite sizes of the synthesized powders were calculated in the range of 200 nm and 76 nm by Williamson-Hall analysis. In addition to structural investigation, dislocation density of the synthesized particles was calculated by Williamson-Smallman relation. Afterwards, photocatalytic performance of Fe2O3 particles was investigated in detail. The photodegradation of methylene blue solutions in the presence of light in 20 min with samples 3,4, and 5 in 20 min were 0.937, 0.896, and 0.855, respectively. Moreover, the photodegradation of methylene blue solution with sample 5 for 15, 30, and 45 min were 0.9, 0.828, and 0.757, respectively. A photocatalytic activity of 24.25% has been observed under optimum conditions for the time interval of 45 min.
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Affiliation(s)
- Elif EMİL-KAYA
- Department of Materials Science and Engineering, Faculty of Georesources and Materials Engineering, RWTH Aachen University, Aachen,
Germany
- Department of Materials Science and Technology, Faculty of Science, Turkish-German University, İstanbul,
Turkey
- Department of Metallurgical and Materials Engineering, Faculty of Chemical and Metallurgical Engineering, İstanbul Technical University, İstanbul,
Turkey
| | - Burak EVREN
- Department of Materials Science and Technology, Faculty of Science, Turkish-German University, İstanbul,
Turkey
- Department of Metallurgical and Materials Engineering, Faculty of Chemical and Metallurgical Engineering, İstanbul Technical University, İstanbul,
Turkey
| | - Zeynep ERDÖL
- Department of Materials Science and Technology, Faculty of Science, Turkish-German University, İstanbul,
Turkey
- Department of Materials Science and Engineering, Faculty of Engineering, Gebze Technical University, Kocaeli,
Turkey
| | - Duygu EKİNCİ
- Department of Materials Science and Technology, Faculty of Science, Turkish-German University, İstanbul,
Turkey
| | - Mehmet İPEKOĞLU
- Department of Mechanical Engineering, Faculty of Engineering, Turkish-German University, İstanbul,
Turkey
| | - Sibel ÖZENLER
- Department of Mechanical Engineering, Faculty of Engineering, Turkish-German University, İstanbul,
Turkey
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10
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Triyono D, Yunida Y, Rafsanjani RA. Effect of Heat Treatment on Structural, Magnetic and Electrical Properties of La 2FeMnO 6. Materials (Basel) 2021; 14:7501. [PMID: 34947097 PMCID: PMC8709439 DOI: 10.3390/ma14247501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 11/25/2022]
Abstract
In this study, the effect of heat treatment on the structural, magnetic and electrical properties of La2FeMnO6 prepared via the sol-gel and sintering method were investigated. The heat-treatment conditions, i.e., the calcination temperature (1023 K and 1173 K), sintering temperature and time (1273 K for 1 and 3 h) were carried out. X-ray diffraction (XRD) revealed orthorhombic pnma (62) symmetry without any impurity phase for all samples. X-ray photoelectron spectroscopy confirmed the presence of Fe2+-Fe3+-Fe4+ and Mn3+-Mn4+ mixed states, and lanthanum and oxygen vacancies resulting in various magnetic exchange interactions. Furthermore, the magnetisation hysteresis showed enhanced hysteresis loops accompanied by an increase in magnetisation parameters with calcination temperature. The Raman phonon parameters induced a redshift in the phonon modes, alongside an increase in the intensity and compression of the linewidth, reflecting a decrease in lattice distortion, which was confirmed by XRD. The temperature-dependent conductivity showed that the conduction mechanism is dominated by p-type polaron hopping, and the lowest activation energy was approximately 0.237 ± 0.003 eV for the minimum heat-treatment conditions. These results show that varying heat-treatment conditions can significantly affect the structural, magnetic and electrical properties of the La2FeMnO6 system.
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Affiliation(s)
- Djoko Triyono
- Department of Physics, Faculty of Mathematics and Natural Science (FMIPA), Universitas Indonesia Depok, Depok 16424, Indonesia; (Y.Y.); (R.A.R.)
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Hornak J. Synthesis, Properties, and Selected Technical Applications of Magnesium Oxide Nanoparticles: A Review. Int J Mol Sci 2021; 22:ijms222312752. [PMID: 34884556 PMCID: PMC8657440 DOI: 10.3390/ijms222312752] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 11/16/2022] Open
Abstract
In the last few decades, there has been a trend involving the use of nanoscale fillers in a variety of applications. Significant improvements have been achieved in the areas of their preparation and further applications (e.g., in industry, agriculture, and medicine). One of these promising materials is magnesium oxide (MgO), the unique properties of which make it a suitable candidate for use in a wide range of applications. Generally, MgO is a white, hygroscopic solid mineral, and its lattice consists of Mg2+ ions and O2− ions. Nanostructured MgO can be prepared through different chemical (bottom-up approach) or physical (top-down approach) routes. The required resultant properties (e.g., bandgap, crystallite size, and shape) can be achieved depending on the reaction conditions, basic starting materials, or their concentrations. In addition to its unique material properties, MgO is also potentially of interest due to its nontoxicity and environmental friendliness, which allow it to be widely used in medicine and biotechnological applications.
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Affiliation(s)
- Jaroslav Hornak
- Department of Materials and Technology, Faculty of Electrical Engineering, University of West Bohemia, 301 00 Pilsen, Czech Republic
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12
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Canchanya-Huaman Y, Mayta-Armas AF, Pomalaya-Velasco J, Bendezú-Roca Y, Guerra JA, Ramos-Guivar JA. Strain and Grain Size Determination of CeO 2 and TiO 2 Nanoparticles: Comparing Integral Breadth Methods versus Rietveld, μ-Raman, and TEM. Nanomaterials (Basel) 2021; 11:nano11092311. [PMID: 34578630 PMCID: PMC8469540 DOI: 10.3390/nano11092311] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/01/2021] [Accepted: 09/01/2021] [Indexed: 12/12/2022]
Abstract
Various crystallite size estimation methods were used to analyze X-ray diffractograms of spherical cerium dioxide and titanium dioxide anatase nanoparticles aiming to evaluate their reliability and limitations. The microstructural parameters were estimated from several integral breadth methods such as Scherrer, Monshi, Williamson–Hall, and their variants: (i) uniform deformation model, (ii) uniform strain deformation model, and (iii) uniform deformation energy density model. We also employed the size–strain plot and Halder–Wagner method. For this purpose, an instrumental resolution function of an Al2O3 standard was used to subtract the instrumental broadening to estimate the crystallite sizes and strain, and the linear regression analysis was used to compare all the models based on the coefficient of determination. The Rietveld whole powder pattern decomposition method was introduced for comparison purposes, being the best candidate to fit the X-ray diffraction data of metal-oxide nanoparticles. Refined microstructural parameters were obtained using the anisotropic spherical harmonic size approach and correlated with the above estimation methods and transmission electron microscopy images. In addition, μ-Raman spectra were recorded for each material, estimating the mean crystallite size for comparison by means of a phonon confinement model.
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Affiliation(s)
- Yamerson Canchanya-Huaman
- Laboratorio de No Metálicos, Facultad de Ingeniería Química, Universidad Nacional del Centro del Perú (UNCP), Av. Mariscal Ramón Castilla No. 3909, El Tambo, Huancayo 12000, Peru; (Y.C.-H.); (A.F.M.-A.); (J.P.-V.); (Y.B.-R.)
| | - Angie F. Mayta-Armas
- Laboratorio de No Metálicos, Facultad de Ingeniería Química, Universidad Nacional del Centro del Perú (UNCP), Av. Mariscal Ramón Castilla No. 3909, El Tambo, Huancayo 12000, Peru; (Y.C.-H.); (A.F.M.-A.); (J.P.-V.); (Y.B.-R.)
| | - Jemina Pomalaya-Velasco
- Laboratorio de No Metálicos, Facultad de Ingeniería Química, Universidad Nacional del Centro del Perú (UNCP), Av. Mariscal Ramón Castilla No. 3909, El Tambo, Huancayo 12000, Peru; (Y.C.-H.); (A.F.M.-A.); (J.P.-V.); (Y.B.-R.)
| | - Yéssica Bendezú-Roca
- Laboratorio de No Metálicos, Facultad de Ingeniería Química, Universidad Nacional del Centro del Perú (UNCP), Av. Mariscal Ramón Castilla No. 3909, El Tambo, Huancayo 12000, Peru; (Y.C.-H.); (A.F.M.-A.); (J.P.-V.); (Y.B.-R.)
| | - Jorge Andres Guerra
- Departamento de Ciencias, Sección Física, Pontificia Universidad Católica del Perú, Av. Universitaria 1801, Lima 15088, Peru;
| | - Juan A. Ramos-Guivar
- Grupo de Investigación de Nanotecnología Aplicada para Biorremediación Ambiental, Energía, Biomedicina y Agricultura (NANOTECH), Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Av. Venezuela Cdra 34 S/N, Ciudad Universitaria, Lima 15081, Peru
- Correspondence: ; Tel.: +51-1-914728212
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Shi M, Qiu T, Tang B, Zhang G, Yao R, Xu W, Chen J, Fu X, Ning H, Peng J. Temperature-Controlled Crystal Size of Wide Band Gap Nickel Oxide and Its Application in Electrochromism. Micromachines (Basel) 2021; 12:80. [PMID: 33466688 DOI: 10.3390/mi12010080] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/02/2021] [Accepted: 01/11/2021] [Indexed: 11/17/2022]
Abstract
Nickel oxide (NiO) is a wide band gap semiconductor material that is used as an electrochromic layer or an ion storage layer in electrochromic devices. In this work, the effect of annealing temperature on sol-gel NiO films was investigated. Fourier transform infrared spectroscopy (FTIR) showed that the formation of NiO via decomposition of the precursor nickel acetate occurred at about 300 °C. Meanwhile, an increase in roughness was observed by Atomic force microscope (AFM), and precipitation of a large number of crystallites was observed at 500 °C. X-ray Diffraction (XRD) showed that the NiO film obtained at such a temperature showed a degree of crystallinity. The film crystallinity and crystallite size also increased with increasing annealing temperature. An ultraviolet spectrophotometer was used to investigate the optical band gap of the colored NiO films, and it was found that the band gap increased from 3.65 eV to 3.74 eV with the increase in annealing temperature. An electrochromic test further showed that optical modulation density and coloring efficiency decreased with the increase in crystallite size. The electrochromic reaction of the nickel oxide film is more likely to occur at the crystal interface and is closely related to the change of the optical band gap. An NiO film with smaller crystallite size is more conducive to ion implantation and the films treated at 300 °C exhibit optimum electrochromic behavior.
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Duan H, Tian Y, Gong S, Zhang B, Lu Z, Xia Y, Shi Y, Qiao C. Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol. Nanomaterials (Basel) 2020; 10:E2246. [PMID: 33198370 PMCID: PMC7698081 DOI: 10.3390/nano10112246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/04/2022]
Abstract
Herein, Pt/HZSM-5 zeolite catalysts with different crystallite sizes ranging from nanosheet (~2 nm) to bulk crystals (~1.5 μm) have been prepared for the hydrodeoxygenation of guaiacol, and their effects on the reaction pathway and product selectivity were explored. HZSM-5 zeolites prepared by seeding (Pt/Z-40: ~40 nm) or templating (Pt/NS-2: ~2 nm) fabricated intra-crystalline mesopores and thus enhanced the reaction rate by promoting the diffusion of various molecules, especially the bulky ones such as guaiacol and 2-methoxycyclohexanol, leading to a higher cyclohexane selectivity of up to 80 wt % (both for Pt/Z-40 and Pt/NS-2) compared to 70 wt % for bulky HZSM-5 (Pt/CZ: ~1.5 μm) at 250 °C and 120 min. Furthermore, decreased crystallite sizes more effectively promoted the dispersion of Pt particles than bulky HZSM-5 (Pt/Z-400: ~400 nm and Pt/CZ). The relatively low distance between Pt and acidic sites on the Pt/Z-40 catalyst enhanced the metal/support interaction and induced the reaction between the guaiacol molecules adsorbed on the acidic sites and the metal-activated hydrogen species, which was found more favorable for deoxygenation than for hydrogenation of oxygen-containing molecules. In addition, Pt/NS-2 catalyst with a highly exposed surface facilitated more diverse reaction pathways such as alkyl transfer and isomerization.
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Affiliation(s)
- Haonan Duan
- Henan Province Engineering Research Center of Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China;
| | - Yajie Tian
- Henan Province Engineering Research Center of Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China;
| | - Siyuan Gong
- Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (S.G.); (B.Z.); (Z.L.)
| | - Bofeng Zhang
- Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (S.G.); (B.Z.); (Z.L.)
| | - Zongjing Lu
- Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (S.G.); (B.Z.); (Z.L.)
| | - Yinqiang Xia
- College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China
| | - Yawei Shi
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China;
| | - Congzhen Qiao
- Henan Province Engineering Research Center of Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China;
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Azeem PA, Evangeline B, Haranath D, Rao RP. Investigation of lanthanum-sensitized CaZrO 3 blue nanophosphors for white light-emitting diode applications. LUMINESCENCE 2020; 36:481-488. [PMID: 33080101 DOI: 10.1002/bio.3967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/04/2020] [Accepted: 10/11/2020] [Indexed: 11/07/2022]
Abstract
In the present study, CaZrO3 nanophosphors were sensitized with lanthanum (La) at different concentrations (0.5, 1.0, 1.5, 2.0, and 2.5) prepared using polyvinyl alcohol as the chelating agent through the sol-gel method. To study their structural and optical properties, samples were characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The XRD results revealed that samples were well crystallized and average crystallite sizes were calculated. The average crystallite size value was in good agreement with the value obtained from TEM analysis. Energy dispersive spectroscopy and FE-SEM confirmed the existence of La in the prepared samples. In the PL spectra, La-sensitized samples exhibited three bands at 402 nm, 438 nm, and 463 nm in the visible range when excited at the 260 nm wavelength. As the proportion of La increased, the intensity of bands at 438 nm and 463 nm decreased, whereas the band at 402 nm remained stable. Time-resolved PL spectra illustrated the lifetime of the samples. Corresponding CIE co-ordinates for La-sensitized CaZrO3 were calculated.
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Affiliation(s)
- P Abdul Azeem
- Department of Physics, National Institute of Technology, Warangal, India
| | - B Evangeline
- Department of Physics, National Institute of Technology, Warangal, India
| | - D Haranath
- Department of Physics, National Institute of Technology, Warangal, India
| | - R Prasada Rao
- Centre for Materials for Electronics Technology (C-MET), Pune, India
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Ravaszová S, Dvořák K. Development of Crystallinity of Triclinic Polymorph of Tricalcium Silicate. Materials (Basel) 2020; 13:ma13173734. [PMID: 32847001 PMCID: PMC7504084 DOI: 10.3390/ma13173734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 11/16/2022]
Abstract
Tricalcium silicate phase is one of the main components of modern Portland cements. One of the major industrial challenges in the field of cement production is mapping the influence of individual clinker minerals and their polymorphs on the properties of industrially produced clinkers. The primary goal of this work is to improve the fundamental knowledge of understanding the process of alite formation and development from a crystallographic point of view. This study focuses on the observation of the crystallization process of triclinic alite during the firing process, which to date has not been thoroughly described. The effects of a wide range of temperatures and sintering periods on crystallinity were assessed on samples fired in platinum crucibles in a laboratory furnace. X-ray analysis-together with calculation of crystallinity using Scherrer's equation-was used for observing the crystallite size changes of T1 alite polymorph. According to the acquired results, among the most technologically and economically advantageous regimes of production of a high-quality triclinic alite is the temperature of 1450 °C and sintering time of two hours. The most significant changes in the crystallite size occurred within the first hour of sintering for the whole investigated temperature range.
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17
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Fukuyama Y, Yasuda N, Sugimoto K, Kimura S. X-ray diffraction measurement of a single nanometre-sized particle levitated in air by an optical-trap sample holder. J Synchrotron Radiat 2020; 27:67-74. [PMID: 31868738 DOI: 10.1107/s1600577519013651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
A single-beam optical-trap sample holder for X-ray diffraction measurements with synchrotron radiation has been developed. The sample holder was used to obtain an X-ray diffraction image of a single ZnO particle levitated in air, without mechanical contact, by the optical gradient force exerted by a focused laser beam. The diffraction image showed a Debye ring pattern, which was similar to a powder diffraction pattern of an assemblage of ZnO particles. While the ZnO particle is held by the optical trap in air, it rotates irregularly. Therefore, the Debye ring pattern of the ZnO particle can be clearly obtained even if the ZnO particle is a single grain. Lattice parameters and crystallite size of the single ZnO particle were determined simultaneously. The lattice parameters were determined to be a = 3.2505 ± 0.0005 Å and c = 5.207 ± 0.006 Å, which are consistent with those of the assemblage of ZnO particles. The crystallite size determined by the Scherrer method was 193.4 ± 26.2 nm.
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Affiliation(s)
- Yoshimitsu Fukuyama
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Nobuhiro Yasuda
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Kunihisa Sugimoto
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Shigeru Kimura
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
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Exner J, Pöpke H, Fuchs FM, Kita J, Moos R. Annealing of Gadolinium-Doped Ceria (GDC) Films Produced by the Aerosol Deposition Method. Materials (Basel) 2018; 11:E2072. [PMID: 30360540 DOI: 10.3390/ma11112072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/05/2018] [Accepted: 10/16/2018] [Indexed: 11/16/2022]
Abstract
Solid oxide fuel cells need a diffusion barrier layer to protect the zirconia-based electrolyte if a cobalt-containing cathode material like lanthanum strontium cobalt ferrite (LSCF) is used. This protective layer must prevent the direct contact and interdiffusion of both components while still retaining the oxygen ion transport. Gadolinium-doped ceria (GDC) meets these requirements. However, for a favorable cell performance, oxide ion conducting films that are thin yet dense are required. Films with a thickness in the sub-micrometer to micrometer range were produced by the dry room temperature spray-coating technique, aerosol deposition. Since commercially available GDC powders are usually optimized for the sintering of screen printed films or pressed bulk samples, their particle morphology is nanocrystalline with a high surface area that is not suitable for aerosol deposition. Therefore, different thermal and mechanical powder pretreatment procedures were investigated and linked to the morphology and integrity of the sprayed films. Only if a suitable pretreatment was conducted, dense and well-adhering GDC films were deposited. Otherwise, low-strength films were formed. The ionic conductivity of the resulting dense films was characterized by impedance spectroscopy between 300 °C and 1000 °C upon heating and cooling. A mild annealing occurred up to 900 °C during first heating that slightly increased the electric conductivity of GDC films formed by aerosol deposition.
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Ishikawa K, Miyamoto Y, Tsuchiya A, Hayashi K, Tsuru K, Ohe G. Physical and Histological Comparison of Hydroxyapatite, Carbonate Apatite, and β-Tricalcium Phosphate Bone Substitutes. Materials (Basel) 2018; 11:ma11101993. [PMID: 30332751 PMCID: PMC6213161 DOI: 10.3390/ma11101993] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 02/02/2023]
Abstract
Three commercially available artificial bone substitutes with different compositions, hydroxyapatite (HAp; Neobone®), carbonate apatite (CO₃Ap; Cytrans®), and β-tricalcium phosphate (β-TCP; Cerasorb®), were compared with respect to their physical properties and tissue response to bone, using hybrid dogs. Both Neobone® (HAp) and Cerasorb® (β-TCP) were porous, whereas Cytrans® (CO₃Ap) was dense. Crystallite size and specific surface area (SSA) of Neobone® (HAp), Cytrans® (CO₃Ap), and Cerasorb® (β-TCP) were 75.4 ± 0.9 nm, 30.8 ± 0.8 nm, and 78.5 ± 7.5 nm, and 0.06 m²/g, 18.2 m²/g, and 1.0 m²/g, respectively. These values are consistent with the fact that both Neobone® (HAp) and Cerasorb® (β-TCP) are sintered ceramics, whereas Cytrans® (CO₃Ap) is fabricated in aqueous solution. Dissolution in pH 5.3 solution mimicking Howship's lacunae was fastest in CO₃Ap (Cytrans®), whereas dissolution in pH 7.3 physiological solution was fastest in β-TCP (Cerasorb®). These results indicated that CO₃Ap is stable under physiological conditions and is resorbed at Howship's lacunae. Histological evaluation using hybrid dog mandible bone defect model revealed that new bone was formed from existing bone to the center of the bone defect when reconstructed with CO₃Ap (Cytrans®) at week 4. The amount of bone increased at week 12, and resorption of the CO₃Ap (Cytrans®) was confirmed. β-TCP (Cerasorb®) showed limited bone formation at week 4. However, a larger amount of bone was observed at week 12. Among these three bone substitutes, CO₃Ap (Cytrans®) demonstrated the highest level of new bone formation. These results indicate the possibility that bone substitutes with compositions similar to that of bone may have properties similar to those of bone.
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Affiliation(s)
- Kunio Ishikawa
- Department of Biomaterials, Faculty of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Youji Miyamoto
- Department of Oral Surgery, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramotocho, Tokushima 770-8504, Japan.
| | - Akira Tsuchiya
- Department of Biomaterials, Faculty of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Koichiro Hayashi
- Department of Biomaterials, Faculty of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Kanji Tsuru
- Department of Biomaterials, Faculty of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
- Section of Bioengineering, Department of Dental Engineering, Fukuoka Dental College, Fukuoka 814-0193, Japan.
| | - Go Ohe
- Department of Oral Surgery, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramotocho, Tokushima 770-8504, Japan.
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Osuntokun J, Onwudiwe DC, Ebenso EE. Aqueous extract of broccoli mediated synthesis of CaO nanoparticles and its application in the photocatalytic degradation of bromocrescol green. IET Nanobiotechnol 2018; 12:888-894. [PMID: 30247126 PMCID: PMC8676217 DOI: 10.1049/iet-nbt.2017.0277] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/09/2018] [Accepted: 04/06/2018] [Indexed: 08/03/2023] Open
Abstract
CaO nanoparticles have been prepared using CaCl2 and aqueous extract of broccoli as a precursor and reducing agent, respectively. Different volumes of the aqueous broccoli extract were utilised to obtain Ca(OH)2 and subsequent calcination gave CaO nanoparticles. The synthesised CaO was confirmed by powder X-ray diffraction (XRD). The morphology was studied using transmittance electron microscopy (TEM), and the surface composition of Ca(OH)2 was explored using Fourier transform infrared spectroscopy. The major functional groups present in the capping material responsible for the reduction of the metal salt and the surface passivation of Ca(OH)2 were identified. The XRD pattern revealed cubic phase for all the CaO nanoparticles, and the crystallite size was estimated using Scherrer's equation showed a variation which is dependent on the volume of the extract used. TEM analysis showed different shapes, while the selected area electron diffraction (SAED) results confirmed the crystallinity of the nanoparticles. Thermogravimetric analysis of Ca(OH)2 showed the decomposition product to be CaO. Sample C3, which has the smallest particle size, was used as a catalyst for the degradation of bromocresol green via photo irradiation with ultraviolet light and the result revealed a degradation efficiency of 60.1%.
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Affiliation(s)
- Jejenija Osuntokun
- Faculty of Natural and Agricultural Science, Material Science Innovation and Modelling (MaSIM) Research Focus Area, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa
| | - Damian C Onwudiwe
- Faculty of Natural and Agricultural Science, Material Science Innovation and Modelling (MaSIM) Research Focus Area, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa.
| | - Eno E Ebenso
- Department of Chemistry, Faculty of Natural and Agricultural Science, School of Physical and Chemical Sciences, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa
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Hanft D, Bektas M, Moos R. Powder Pre-Treatment for Aerosol Deposition of Tin Dioxide Coatings for Gas Sensors. Materials (Basel) 2018; 11:ma11081342. [PMID: 30072678 PMCID: PMC6119988 DOI: 10.3390/ma11081342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/23/2018] [Accepted: 07/31/2018] [Indexed: 11/16/2022]
Abstract
The Aerosol Deposition (AD) method has the unique property to allow for manufacturing dense ceramic films at room temperature. As found in many publications, the deposition process is very sensitive to powder properties. In particular, powders of nano-sized particles and grains, e.g., from precipitation, are usually beyond the conventional size range of AD processability, yielding chalk-like films of low mechanical stability. Thus, the conventional AD process is limited in applicability. In this study, we try to overcome this problem by adapting the standard milling treatment of powders for improved deposition by additional temperature pre-treatment. Using commercial tin dioxide and including a temperature treatment for grain growth, makes the powder accessible to deposition. In this way, we achieve optically translucent and conductive SnO2 thick films. With the application such as a gas sensitive film as one of many possible applications for SnO2 thick-films, the sensors show excellent response to various reducing gases. This study shows one exemplary way of extending the range of adequate powder and applications for the AD method.
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Affiliation(s)
- Dominik Hanft
- Department of Functional Materials, University of Bayreuth, 95447 Bayreuth, Germany.
| | - Murat Bektas
- Department of Functional Materials, University of Bayreuth, 95447 Bayreuth, Germany.
| | - Ralf Moos
- Department of Functional Materials, University of Bayreuth, 95447 Bayreuth, Germany.
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Rodríguez-Lugo V, Karthik TVK, Mendoza-Anaya D, Rubio-Rosas E, Villaseñor Cerón LS, Reyes-Valderrama MI, Salinas-Rodríguez E. Wet chemical synthesis of nanocrystalline hydroxyapatite flakes: effect of pH and sintering temperature on structural and morphological properties. R Soc Open Sci 2018; 5:180962. [PMID: 30225084 PMCID: PMC6124097 DOI: 10.1098/rsos.180962] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 07/19/2018] [Indexed: 05/05/2023]
Abstract
Wet chemical synthesis of hydroxyapatite (HAp) nanostructures was carried out with different solution pH values (9, 10 and 11) and sintering temperatures (300°C, 500°C, 700°C and 900°C). The effects of pH and sintering temperature on the structural and morphological properties of nanocrystalline HAp powders were presented. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to obtain the crystalline structure, chemical composition, morphology and particle size of the HAp powders. The TEM analysis is used in order to observe the rod- and flake-like HAp structures. XRD confirms the presence of both HAp hexagonal and monetite phases, although the monetite phase was less abundant in the resultant powders. Increase in pH reduced the monetite phase and enhanced Ca/P ratio from 1.7 to 1.83. Additionally, an increment in sintering temperature increased the crystallite size from 20 to 56 nm. The SEM analysis revealed the formation of semi-spherical and flake-like HAp structures with preferential flake morphology. An increase in pH and sintering temperature resulted in the growth and coalescence of crystals resulting in a porous capsular morphology. The FTIR analysis confirmed the reduction of carbonate stretching modes with an increase in pH and H-O-H antisymmetric stretching mode is eliminated for powders sintered at 900°C confirming the formation of stable and porous HAp powders.
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Affiliation(s)
- V. Rodríguez-Lugo
- Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca—Tulancingo km 4.5, C.P. 42184 Pachuca, Hidalgo, México
- Author for correspondence: V. Rodríguez-Lugo e-mail:
| | - T. V. K. Karthik
- Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca—Tulancingo km 4.5, C.P. 42184 Pachuca, Hidalgo, México
| | - D. Mendoza-Anaya
- Instituto Nacional de Investigaciones Nucleares, Carr. México-Toluca S/N, La Marquesa, Ocoyoacac, Edo. de México C.P. 52750, México
| | - E. Rubio-Rosas
- Benemérita Universidad Autónoma de Puebla, Prolongación de la 24 Sur y San Claudio, Ciudad Universitaria, Sn Manuel, 72570 Puebla, México
| | - L. S. Villaseñor Cerón
- Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca—Tulancingo km 4.5, C.P. 42184 Pachuca, Hidalgo, México
| | - M. I. Reyes-Valderrama
- Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca—Tulancingo km 4.5, C.P. 42184 Pachuca, Hidalgo, México
| | - E. Salinas-Rodríguez
- Área Académica de Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca—Tulancingo km 4.5, C.P. 42184 Pachuca, Hidalgo, México
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23
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Ali A, Rafique A, Kaleemullah M, Abbas G, Ajmal Khan M, Ahmad MA, Raza R. Effect of Alkali Carbonates (Single, Binary, and Ternary) on Doped Ceria: A Composite Electrolyte for Low-Temperature Solid Oxide Fuel Cells. ACS Appl Mater Interfaces 2018; 10:806-818. [PMID: 29256589 DOI: 10.1021/acsami.7b17010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Samarium-doped ceria (SDC) carbonate has become an attractive electrolyte for fuel cells because of its remarkable ion conductivity and high performance. Different doped ceria-carbonate (single-carbonate SDC, binary-carbonate SDC, and ternary-carbonate SDC) electrolytes were synthesized by the coprecipitation/oxalate method, to optimize the electrochemical performance. The structure; morphology; and thermal, optical, and surface properties have been studied using a variety of techniques. The X-ray diffraction results confirmed the successful incorporation of samarium into ceria as a crystalline structure and inclusion of carbonate, which is amorphous in nature. To analyze the conduction mechanism, direct current conductivity was measured in a H2/O2 atmosphere. Doped ceria-binary carbonate ((Li/Na)CO3-SDC) showed the best conductivity of 0.31 S cm-1 and power density of 617 mW cm-2, at 600 °C. The enhancement in the ionic conductivity and performance of the composites is due to the contribution of hybrid ions (O2-, H+). The crystallite size of the composites was in the range 21-41 nm. For the calculation of band gaps, optical absorption spectra of the synthesized powders were analyzed, and they showed a red shift with the band gap energy in the range 2.6-3.01 eV, when compared to that of pure ceria (3.20 eV).
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Affiliation(s)
- Amjad Ali
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
- Department of Physics, University of Okara , Okara 56300, Pakistan
| | - Asia Rafique
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
| | - Muhammad Kaleemullah
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
| | - Ghazanfar Abbas
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
| | - M Ajmal Khan
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201, China
| | - M Ashfaq Ahmad
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
| | - Rizwan Raza
- Department of Physics, COMSATS Institute of Information Technology , Lahore 54000, Pakistan
- Department of Energy Technology, Royal Institute of Technology (KTH) , Stockholm 10044, Sweden
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24
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Miranda MAR, Sasaki JM. The limit of application of the Scherrer equation. Acta Crystallogr A Found Adv 2018; 74:54-65. [PMID: 29269598 DOI: 10.1107/s2053273317014929] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/14/2017] [Indexed: 11/11/2022]
Abstract
The Scherrer equation is a widely used tool to obtain crystallite size from polycrystalline samples. Its limit of applicability has been determined recently, using computer simulations, for a few structures and it was proposed that it is directly dependent on the linear absorption coefficient (μ0) and Bragg angle (θB). In this work, a systematic study of the Scherrer limit is presented, where it is shown that it is equal to approximately 11.9% of the extinction length. It is also shown that absorption imposes a maximum value on it and that this maximum is directly proportional to sin θB/μ0.
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Affiliation(s)
- M A R Miranda
- Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, CEP 60440-970 Fortaleza, Ceará, Brazil
| | - J M Sasaki
- Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, CEP 60440-970 Fortaleza, Ceará, Brazil
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25
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Kumar R, Bakshi SR, Joardar J, Parida S, Raja VS, Singh Raman RK. Structural Evolution during Milling, Annealing, and Rapid Consolidation of Nanocrystalline Fe-10Cr-3Al Powder. Materials (Basel) 2017; 10:ma10030272. [PMID: 28772633 PMCID: PMC5503399 DOI: 10.3390/ma10030272] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 12/04/2022]
Abstract
Structural changes during the deformation-induced synthesis of nanocrystalline Fe–10Cr–3Al alloy powder via high-energy ball milling followed by annealing and rapid consolidation by spark plasma sintering were investigated. Reduction in crystallite size was observed during the synthesis, which was associated with the lattice expansion and rise in dislocation density, reflecting the generation of the excess grain boundary interfacial energy and the excess free volume. Subsequent annealing led to the exponential growth of the crystallites with a concomitant drop in the dislocation density. The rapid consolidation of the as-synthesized nanocrystalline alloy powder by the spark plasma sintering, on the other hand, showed only a limited grain growth due to the reduction of processing time for the consolidation by about 95% when compared to annealing at the same temperature.
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Affiliation(s)
- Rajiv Kumar
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800, Australia.
| | - S R Bakshi
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
| | - Joydip Joardar
- International Advanced Research Centre for Powder Metallurgy and New Materials, Hyderabad 500005, India.
| | - S Parida
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - V S Raja
- Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - R K Singh Raman
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800, Australia.
- Department of Chemical Engineering, Monash University, Melbourne, Victoria 3800, Australia.
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26
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Cîrcu M, Nan A, Borodi G, Liebscher J, Turcu R. Refinement of Magnetite Nanoparticles by Coating with Organic Stabilizers. Nanomaterials (Basel) 2016; 6:nano6120228. [PMID: 28335356 PMCID: PMC5302720 DOI: 10.3390/nano6120228] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/07/2016] [Accepted: 11/18/2016] [Indexed: 01/08/2023]
Abstract
Magnetite nanoparticles are of great importance in nanotechnology and nanomedicine and have found manifold applications. Here, the effect of coating of magnetite nanoparticles with organic stabilizers, such as O-phosphoryl ethanolamine, glycerol phosphate, phospho-l-ascorbic acid, phospho-d,l-serine, glycolic acid, lactic acid, d,l-malic acid, and d,l-mandelic acid was studied. Remarkably, this procedure led to an improvement of saturation magnetization in three cases rather than to an unfavorable decrease as usually observed. Detailed X-ray powder diffraction investigations revealed that changes in the average crystallite occurred in the coating process. Surprisingly, changes of the average crystallite sizes in either direction were further observed, when the exposure time to the stabilizer was increased. These results imply a new mechanism for the well-known coating of magnetite nanoparticles with stabilizers. Instead of the hitherto accepted simple anchoring of the stabilizers to the magnetite nanoparticle surfaces, a more complex recrystallization mechanism is likely, wherein partial re-dispersion of magnetite moieties from the nanoparticles and re-deposition are involved. The results can help producers and users of magnetite nanoparticles to obtain optimal results in the production of core shell magnetite nanoparticles.
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Affiliation(s)
- Monica Cîrcu
- National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
| | - Alexandrina Nan
- National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
| | - Gheorghe Borodi
- National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
| | - Jürgen Liebscher
- National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
- Department of Chemistry, Humboldt-University Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Rodica Turcu
- National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
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27
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Bock DC, Kirshenbaum KC, Wang J, Zhang W, Wang F, Wang J, Marschilok AC, Takeuchi KJ, Takeuchi ES. 2D Cross Sectional Analysis and Associated Electrochemistry of Composite Electrodes Containing Dispersed Agglomerates of Nanocrystalline Magnetite, Fe₃O₄. ACS Appl Mater Interfaces 2015; 7:13457-13466. [PMID: 26024206 DOI: 10.1021/acsami.5b02478] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
When electroactive nanomaterials are fully incorporated into an electrode structure, characterization of the crystallite sizes, agglomerate sizes, and dispersion of the electroactive materials can lend insight into the complex electrochemistry associated with composite electrodes. In this study, composite magnetite electrodes were sectioned using ultramicrotome techniques, which facilitated the direct observation of crystallites and agglomerates of magnetite (Fe3O4) as well as their dispersal patterns in large representative sections of electrode, via 2D cross sectional analysis by Transmission Electron Microscopy (TEM). Further, the electrochemistry of these electrodes were recorded, and Transmission X-ray Microscopy (TXM) was used to determine the distribution of oxidation states of the reduced magnetite. Unexpectedly, while two crystallite sizes of magnetite were employed in the production of the composite electrodes, the magnetite agglomerate sizes and degrees of dispersion in the two composite electrodes were similar to each other. This observation illustrates the necessity for careful characterization of composite electrodes, in order to understand the effects of crystallite size, agglomerate size, and level of dispersion on electrochemistry.
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Affiliation(s)
- David C Bock
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - Jiajun Wang
- ‡Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wei Zhang
- ‡Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Feng Wang
- ‡Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jun Wang
- ‡Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Amy C Marschilok
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- §Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794, United States
| | - Kenneth J Takeuchi
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- §Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794, United States
| | - Esther S Takeuchi
- †Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- ‡Brookhaven National Laboratory, Upton, New York 11973, United States
- §Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794, United States
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28
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Chen Z, Liu Z, Qian F. Crystallization of bifonazole and acetaminophen within the matrix of semicrystalline, PEO-PPO-PEO triblock copolymers. Mol Pharm 2015; 12:590-9. [PMID: 25569586 DOI: 10.1021/mp500661v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The morphology and microstructure of crystalline drug/polymer solid dispersions could influence their physical stability and dissolution performance. In this study, the drug crystallization mechanism within PEG, PPG, and poloxamer matrix was investigated, and the resultant microstructure of various solid dispersions of acetaminophen (ACM) and bifonazole (BFZ) in the aforementioned polymers was characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide/small-angle X-ray diffraction (WAXD/SAXS). With a stronger molecular interaction with the PEG segments, ACM decreased the crystallization onset temperature and crystallinity of PEG and poloxamers much more than BFZ. The stronger molecular interaction and better miscibility between ACM and PEG also induced a more defective lamellar structure in the ACM solid dispersions compared with that in the BFZ systems, as revealed by DSC and SAXS investigation. Observed under polarized optical microscopy, PEG, PPG, and poloxamer could all significantly improve the crystallization rate of ACM and BFZ, because of the largely reduced Tg of the solid dispersions by these low Tg polymers. Moreover, when the drug loading was below 60%, crystallization of BFZ in PEG or poloxamer occurred preferably along the radial direction of PEG spherulite, rather than the perpendicular direction, which was attributed to the geometric restriction of well-ordered polymer lamellar structure in the BFZ solid dispersions. Similar phenomena were not observed in the ACM solid dispersions regardless of the drug loading, presumably because ACM could diffuse freely across the perpendicular direction of the PEG spherulite, through the well-connected interlamellar or interfibrillar spaces produced by the defective PEG lamellar structure. The different drug-polymer interaction also caused a difference in the microstructure of polymer crystal, as well as a difference in drug distribution within the polymer matrix, which then synergistically facilitated a "confined crystallization" process to reduce the drug crystallite size below 100 nm.
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Affiliation(s)
- Zhen Chen
- Department of Pharmacology and Pharmaceutical Sciences, School of Medicine and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University , Beijing 100084, P. R. China
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29
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Hong JY, Kong J, Kim SH. Spatially controlled graphitization of reduced graphene oxide films via a green mechanical approach. Small 2014; 10:4839-4844. [PMID: 25070767 DOI: 10.1002/smll.201401185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/27/2014] [Indexed: 06/03/2023]
Abstract
An effective approach to fabricate micropatterned reduced graphene oxide sheets is explored on the basis of the pressure-assisted thermal graphitization as a concept of eco-friendly method. The high pressure can considerably reduce the graphitization temperature and substantially accelerate the kinetics of phase transformation of non-crystalline graphene domain, leading to enhance the degree of graphitization.
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Affiliation(s)
- Jin-Yong Hong
- Department of Electrical Engineering and Computer Science, Massachusetts Institute o Technology, Cambridge, MA, 02139, USA
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30
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Saheb N, Aliyu IK, Hassan SF, Al-Aqeeli N. Matrix Structure Evolution and Nanoreinforcement Distribution in Mechanically Milled and Spark Plasma Sintered Al-SiC Nanocomposites. Materials (Basel) 2014; 7:6748-67. [PMID: 28788210 DOI: 10.3390/ma7096748] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/30/2014] [Accepted: 09/09/2014] [Indexed: 12/03/2022]
Abstract
Development of homogenous metal matrix nanocomposites with uniform distribution of nanoreinforcement, preserved matrix nanostructure features, and improved properties, was possible by means of innovative processing techniques. In this work, Al-SiC nanocomposites were synthesized by mechanical milling and consolidated through spark plasma sintering. Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray Spectroscopy (EDS) facility was used for the characterization of the extent of SiC particles’ distribution in the mechanically milled powders and spark plasma sintered samples. The change of the matrix crystallite size and lattice strain during milling and sintering was followed through X-ray diffraction (XRD). The density and hardness of the developed materials were evaluated as function of SiC content at fixed sintering conditions using a densimeter and a digital microhardness tester, respectively. It was found that milling for 24 h led to uniform distribution of SiC nanoreinforcement, reduced particle size and crystallite size of the aluminum matrix, and increased lattice strain. The presence and amount of SiC reinforcement enhanced the milling effect. The uniform distribution of SiC achieved by mechanical milling was maintained in sintered samples. Sintering led to the increase in the crystallite size of the aluminum matrix; however, it remained less than 100 nm in the composite containing 10 wt.% SiC. Density and hardness of sintered nanocomposites were reported and compared with those published in the literature.
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31
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Shrama SK, Saurakhiya N, Barthwal S, Kumar R, Sharma A. Tuning of structural, optical, and magnetic properties of ultrathin and thin ZnO nanowire arrays for nano device applications. Nanoscale Res Lett 2014; 9:122. [PMID: 24636275 PMCID: PMC4003861 DOI: 10.1186/1556-276x-9-122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/19/2014] [Indexed: 05/26/2023]
Abstract
One-dimensional (1-D) ultrathin (15 nm) and thin (100 nm) aligned 1-D (0001) and (0001¯) oriented zinc oxide (ZnO) nanowire (NW) arrays were fabricated on copper substrates by one-step electrochemical deposition inside the pores of polycarbonate membranes. The aspect ratio dependence of the compressive stress because of the lattice mismatch between NW array/substrate interface and crystallite size variations is investigated. X-ray diffraction results show that the polycrystalline ZnO NWs have a wurtzite structure with a = 3.24 Å, c = 5.20 Å, and [002] elongation. HRTEM and SAED pattern confirmed the polycrystalline nature of ultrathin ZnO NWs and lattice spacing of 0.58 nm. The crystallite size and compressive stress in as-grown 15- and 100-nm wires are 12.8 nm and 0.2248 GPa and 22.8 nm and 0.1359 GPa, which changed to 16.1 nm and 1.0307 GPa and 47.5 nm and 1.1677 GPa after annealing at 873 K in ultrahigh vacuum (UHV), respectively. Micro-Raman spectroscopy showed that the increase in E2 (high) phonon frequency corresponds to much higher compressive stresses in ultrathin NW arrays. The minimum-maximum magnetization magnitude for the as-grown ultrathin and thin NW arrays are approximately 8.45 × 10-3 to 8.10 × 10-3 emu/g and approximately 2.22 × 10-7 to 2.190 × 10-7 emu/g, respectively. The magnetization in 15-nm NW arrays is about 4 orders of magnitude higher than that in the 100 nm arrays but can be reduced greatly by the UHV annealing. The origin of ultrathin and thin NW array ferromagnetism may be the exchange interactions between localized electron spin moments resulting from oxygen vacancies at the surfaces of ZnO NWs. The n-type conductivity of 15-nm NW array is higher by about a factor of 2 compared to that of the 100-nm ZnO NWs, and both can be greatly enhanced by UHV annealing. The ability to tune the stresses and the structural and relative occupancies of ZnO NWs in a wide range by annealing has important implications for the design of advanced photonic, electronic, and magneto-optic nano devices.
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Affiliation(s)
- Satinder K Shrama
- School of Computing and Electrical Engineering, Indian Institute of Technology (IIT)-Mandi, Mandi, Himanchal Pradesh 175001, India
- DST Unit on Nanosciences, Department of Chemical Engineering, Indian Institute of Technology (IIT)-Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Neelam Saurakhiya
- DST Unit on Nanosciences, Department of Chemical Engineering, Indian Institute of Technology (IIT)-Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Sumit Barthwal
- DST Unit on Nanosciences, Department of Chemical Engineering, Indian Institute of Technology (IIT)-Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Rudra Kumar
- DST Unit on Nanosciences, Department of Chemical Engineering, Indian Institute of Technology (IIT)-Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Ashutosh Sharma
- DST Unit on Nanosciences, Department of Chemical Engineering, Indian Institute of Technology (IIT)-Kanpur, Kanpur, Uttar Pradesh 208016, India
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32
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Kamminga JD, Seijbel LJ. Diffraction Line Broadening Analysis if Broadening Is Caused by Both Dislocations and Limited Crystallite Size. J Res Natl Inst Stand Technol 2004; 109:65-74. [PMID: 27366597 PMCID: PMC4849624 DOI: 10.6028/jres.109.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 04/11/2003] [Indexed: 06/06/2023]
Abstract
The determination of dislocation distribution parameters is discussed for specimens where both strain broadening caused by dislocations and size broadening occur. If the strain broadening is well described by a model due to Wilkens, several methods are possible for the analysis of the broadening of diffraction lines. In sputter deposited nickel layers, three different methods for diffraction line broadening analysis yield identical results. The recrystallization of the nickel layers was investigated by annealing the layers at various temperatures in the range 300 K to 500 K. With increasing annealing temperature, the microstructure of the layers changed from a microstructure with small grains and high dislocation density, via a microstructure that is a mixture of small grains with high dislocation density and large grains with low dislocation density, to a microstructure with large grains and low dislocation density.
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Affiliation(s)
- J-D Kamminga
- Netherlands Institute for Metals Research, Rotterdamseweg 137, NL-2628 AL Delft, The Netherlands
| | - L J Seijbel
- Bruker Nonius BV, Oostsingel 209, NL-2612 HL Delft, The Netherlands
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