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Ene VL, Lupu VR, Condor CV, Patru RE, Hrib LM, Amarande L, Nicoara AI, Pintilie L, Ianculescu AC. Influence of Grain Size on Dielectric Behavior in Lead-Free 0.5 Ba(Zr 0.2Ti 0.8)O 3-0.5 (Ba 0.7Ca 0.3)TiO 3 Ceramics. Nanomaterials (Basel) 2023; 13:2934. [PMID: 37999288 PMCID: PMC10675762 DOI: 10.3390/nano13222934] [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: 10/11/2023] [Revised: 11/05/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023]
Abstract
Fine-tuning of grain sizes can significantly influence the interaction between different dielectric phenomena, allowing the development of materials with tailored dielectric resistivity. By virtue of various synthesis mechanisms, a pathway to manipulate grain sizes and, consequently, tune the material's dielectric response is revealed. Understanding these intricate relationships between granulation and dielectric properties can pave the way for designing and optimizing materials for specific applications where tailored dielectric responses are sought. The experimental part involved the fabrication of dense BCT-BZT ceramics with different grain sizes by varying the synthesis (conventional solid-state reaction route and sol-gel) and consolidation methods. Both consolidation methods produced well-crystallized specimens, with Ba0.85Ca0.15O3Ti0.9Zr0.1 (BCTZ) perovskite as the major phase. Conventional sintering resulted in microstructured and submicron-structured BCT-BZT ceramics, with average grain sizes of 2.35 μm for the solid-state sample and 0.91 μm for the sol-gel synthesized ceramic. However, spark plasma sintering produced a nanocrystalline specimen with an average grain size of 67.5 nm. As the grain size decreases, there is a noticeable decrease in the maximum permittivity, a significant reduction in dielectric losses, and a shifting of the Curie temperature towards lower values.
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Affiliation(s)
- Vladimir Lucian Ene
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1–7 Gheorghe Polizu Street, 011061 Bucharest, Romania; (V.L.E.); (V.R.L.); (C.V.C.); (A.I.N.)
- National Research Center for Micro and Nanomaterials, National University of Science and Technology Politehnica Bucharest, 060042 Bucharest, Romania
| | - Valentin Razvan Lupu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1–7 Gheorghe Polizu Street, 011061 Bucharest, Romania; (V.L.E.); (V.R.L.); (C.V.C.); (A.I.N.)
| | - Claudiu Vasile Condor
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1–7 Gheorghe Polizu Street, 011061 Bucharest, Romania; (V.L.E.); (V.R.L.); (C.V.C.); (A.I.N.)
| | - Roxana Elena Patru
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (R.E.P.); (L.M.H.); (L.A.); (L.P.)
| | - Luminita Mirela Hrib
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (R.E.P.); (L.M.H.); (L.A.); (L.P.)
| | - Luminita Amarande
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (R.E.P.); (L.M.H.); (L.A.); (L.P.)
| | - Adrian Ionut Nicoara
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1–7 Gheorghe Polizu Street, 011061 Bucharest, Romania; (V.L.E.); (V.R.L.); (C.V.C.); (A.I.N.)
- National Research Center for Micro and Nanomaterials, National University of Science and Technology Politehnica Bucharest, 060042 Bucharest, Romania
| | - Lucian Pintilie
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (R.E.P.); (L.M.H.); (L.A.); (L.P.)
| | - Adelina-Carmen Ianculescu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, National University of Science and Technology Politehnica Bucharest, 1–7 Gheorghe Polizu Street, 011061 Bucharest, Romania; (V.L.E.); (V.R.L.); (C.V.C.); (A.I.N.)
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Nicolicescu C, Nicoară VH, Pascu CI, Gheorghe Ș, Burada CO, Marinca TF, Popa F. Morphological Analyses of W/Cu Functional Graded Materials Obtained by Conventional and Spark Plasma Sintering. Materials (Basel) 2023; 16:ma16114126. [PMID: 37297259 DOI: 10.3390/ma16114126] [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: 04/29/2023] [Revised: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
The paper presents the analysis of two compaction methods for obtaining W/Cu Functional Graded Materials (FGMs) consisting of three layers with the following compositions (% weight): first layer 80 W/20 Cu, second layer 75 W/25 Cu, and third layer 65 W/35 Cu. Each layer composition was obtained using powders obtained through mechanical milling. The two compaction methods were Spark Plasma Sintering (SPS) and Conventional Sintering (CS). The samples obtained after the SPS and CS were investigated from morphological (scanning electron microscopy-SEM) and compositional (energy dispersive X-ray spectroscopy-EDX) points of views. Additionally, the porosities and the densities of each layer in both cases were studied. It was found that the densities of the sample's layers obtained through SPS are superior to those obtained through CS. The research emphasizes that, from a morphological point of view, the SPS process is recommended for W/Cu-FGMs, having raw materials as fine-graded powders against the CS process.
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Affiliation(s)
| | | | | | - Ștefan Gheorghe
- Faculty of Mechanics, University of Craiova, 200512 Craiova, Romania
| | | | - Traian Florin Marinca
- Faculty of Materials Engineering and Environment, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania
| | - Florin Popa
- Faculty of Materials Engineering and Environment, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania
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Qu S, Li J, Liu Z. New Strategy for Preparation of Yttria Powders with Atypical Morphologies and Their Sintering Behavior. Materials (Basel) 2023; 16:2854. [PMID: 37049148 PMCID: PMC10095629 DOI: 10.3390/ma16072854] [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] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/29/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
A modified precipitation method was used to prepare yttria powers for the fabrication of yttria ceramics in this study. The precipitation behavior, phase evolution, and shape of the yttria precursor were all examined in the presence or absence of an electric field. The findings demonstrate that the phases of the yttria precursor were Y2(CO3)3·2H2O with and without an electric field, while the morphology changed from flake to needle-like under the action of the electric field. After calcining both yttria precursors at 750 °C, yttria powders with similar morphologies were obtained and then densified via conventional sintering (CS) and spark plasma sintering (SPS). The densification and thermal shock resistance of the yttria ceramics were investigated. The yttria ceramics sintered using SPS had higher bulk density and thermal shock resistance than the samples sintered using CS. When the sintering process for the ceramics sintered from needle-like yttria powder was switched from CS to SPS, the bulk density increased from 4.44 g·cm-3 to 5.01 g·cm-3, while the number of thermal shock tests increased from two to six. The denser samples showed better thermal shock resistance, which may be related to the fracture mechanism shifting from intergranular fracture to transgranular fracture.
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Affiliation(s)
- Sheng Qu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Jinlian Li
- Iron and Steel Research Institute of Ansteel Group, Anshan 114051, China
| | - Zhaoyang Liu
- School of Metallurgy, Northeastern University, Shenyang 110819, China
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Evangeline T G, Annamalai A R, Ctibor P. Effect of Europium Addition on the Microstructure and Dielectric Properties of CCTO Ceramic Prepared Using Conventional and Microwave Sintering. Molecules 2023; 28:molecules28041649. [PMID: 36838637 PMCID: PMC9963229 DOI: 10.3390/molecules28041649] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
In this work, Eu2O3-doped (CaCu3Ti4O12)x of low dielectric loss have been fabricated using both conventional (CS) and microwave sintering (MWS), where x = Eu2O3 = 0.1, 0.2, and 0.3, respectively. According to X-ray diffraction (XRD) and scanning electron microscope (SEM) reports, increasing the concentration of Eu3+ in the CCTO lattice causes the grain size of the MWS samples to increase and vice versa for CS. The X-ray photoelectron spectroscopy (XPS) delineated the binding energies and charge states of the Cu2+/Cu+ and Ti4+/Ti3+ transition ions. Energy dispersive spectroscopy (EDS) analysis revealed no Cu-rich phase along the grain boundaries that directly impacts the dielectric properties. The dielectric characteristics, which include dielectric constant (ε) and the loss (tan δ), were examined using broadband dielectric spectrometer (BDS) from 10 to 107 Hz at ambient temperature. The dielectric constant was >104 and >102 for CS and MWS samples at x > 0.1, respectively, with the low loss being constant even at high frequencies due to the effective suppression of tan δ by Eu3+. This ceramic of low dielectric loss has potential for commercial applications at comparatively high frequencies.
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Affiliation(s)
- Gecil Evangeline T
- School of Mechanical Engineering, Vellore Institute of Technology, Vellore 632014, India
| | - Raja Annamalai A
- Centre for Innovative Manufacturing Research, Vellore Institute of Technology, Vellore 632014, India
- Correspondence:
| | - Pavel Ctibor
- The Czech Academy of Sciences, Institute of Plasma Physics, U Slovanky 1a, 182 00 Prague, Czech Republic
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Pandey AK, Gautam RK, Behera CK. Microstructure, mechanical strength, chemical resistance, and antibacterial behavior of Ti-5Cu- x%Nb biomedical alloy. Biomed Mater 2022; 17. [PMID: 35679847 DOI: 10.1088/1748-605x/ac7763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 09/08/2021] [Accepted: 06/09/2022] [Indexed: 01/01/2023]
Abstract
Titanium-based biomedical alloys are susceptible as they are used as a substitute for human bone. In this study, titanium alloy, Ti-5Cu-x%Nb (x= 0, 5, 10, 15) (%wt) was developed by powder metallurgy route. The effect of alloying niobium with Ti-5Cu alloy and its effect on the microstructure, mechanical strength, corrosion resistance, and antibacterial properties have been evaluated. The results show that the sintered alloy has bothα-Ti and Ti2Cu phases. With increasing niobium content in the alloy,β-Ti was also detected. Additionally, it was found that the micro-hardness and compressive strength of the studied alloy was better than commercially pure titanium (cpTi), while the Young's modulus was lower than cpTi. These properties are highly favorable for using this alloy to replicate the human cortical bone. The alloy was also tested for anticorrosive property in Ringer's solution. The antibacterial activity was also examined forStaphylococcus aureusandEscherichia colibacteria. The alloy showed promising anticorrosive and antibacterial ability.
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Affiliation(s)
- Anurag Kumar Pandey
- Department of Mechanical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi, 221005, India
| | - R K Gautam
- Department of Mechanical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi, 221005, India
| | - C K Behera
- Department of Metallurgical Engineering, Indian Institute of Technology (BHU) Varanasi, Varanasi, 221005, India
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Equbal A, Ali M, Equbal MA, Srivastava SC, Khan ZA, Equbal MI, Badruddin IA, El-Hady KM, Kamangar S. Characteristics of Conventional and Microwave Sintered Iron Ore Preform. Materials (Basel) 2022; 15:ma15072655. [PMID: 35407987 PMCID: PMC9000582 DOI: 10.3390/ma15072655] [Citation(s) in RCA: 1] [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: 02/26/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 12/10/2022]
Abstract
In this study, compacted hematite (Fe2O3) preforms were made and sintered at various temperatures, such as 1250 °C and 1300 °C, using both conventional and microwave sintering methods. The density, porosity, microhardness, cold crushing strength, microphotographs, and X-ray diffraction (XRD) analysis of the sintered preforms were used to evaluate the performance of the two sintering methods. It was found that microwave sintered preforms possessed lesser porosity and higher density than conventionally sintered preforms owing to uniform heating of the powdered ore in microwave sintering method. Furthermore, it was also observed that microwave sintered preforms exhibited relatively higher cold crushing strength and hardness than conventionally sintered preforms. Thus, the overall results revealed that microwave sintering yielded better properties considered in the present study.
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Affiliation(s)
- Azhar Equbal
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Jamia Millia Islamia (A Central University), New Delhi 110025, India;
- Correspondence: (A.E.); (I.A.B.)
| | - Mohammad Ali
- Department of Production Engineering, Birla Institute of Technology, Ranchi 835215, India; (M.A.); (S.C.S.)
| | - Md. Asif Equbal
- Department of Mechanical Engineering, Cambridge Institute of Technology, Ranchi 835103, India;
| | - S. C. Srivastava
- Department of Production Engineering, Birla Institute of Technology, Ranchi 835215, India; (M.A.); (S.C.S.)
| | - Zahid A. Khan
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Jamia Millia Islamia (A Central University), New Delhi 110025, India;
| | - Md. Israr Equbal
- Mechanical Engineering Section, University Polytechnic, Aligarh Muslim University, Aligarh 202002, India;
| | - Irfan Anjum Badruddin
- Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, Saudi Arabia;
- Mechanical Engineering Department, College of Engineering, King Khalid University, Abha 61413, Saudi Arabia
- Correspondence: (A.E.); (I.A.B.)
| | - Khalid Mohamed El-Hady
- Civil Engineering Department, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia;
| | - Sarfaraz Kamangar
- Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, Saudi Arabia;
- Mechanical Engineering Department, College of Engineering, King Khalid University, Abha 61413, Saudi Arabia
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Muthuchamy A, Srikanth M, Agrawal DK, Annamalai AR. Effect of Microwave and Conventional Modes of Heating on Sintering Behavior, Microstructural Evolution and Mechanical Properties of Al-Cu-Mn Alloys. Molecules 2021; 26:3675. [PMID: 34208612 DOI: 10.3390/molecules26123675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 11/16/2022] Open
Abstract
In this research, we intended to examine the effect of heating mode on the densification, microstructure, mechanical properties, and corrosion resistance of sintered aluminum alloys. The compacts were sintered in conventional (radiation-heated) and microwave (2.45 GHz, multimode) sintering furnaces followed by aging. Detailed analysis of the final sintered aluminum alloys was done using optical and scanning electron microscopes. The observations revealed that the microwave sintered sample has a relatively finer microstructure compared to its conventionally sintered counterparts. The experimental results also show that microwave sintered alloy has the best mechanical properties over conventionally sintered compacts. Similarly, the microwave sintered samples showed better corrosion resistance than conventionally sintered ones.
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Guoxin H, Ying Y, Yuemei J, Wenjing X. [Study on friction and wear properties of dental zirconia ceramics processed by microwave and conventional sintering methods]. Hua Xi Kou Qiang Yi Xue Za Zhi 2017; 35:150-154. [PMID: 28682544 PMCID: PMC7029995 DOI: 10.7518/hxkq.2017.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/16/2016] [Indexed: 06/07/2023]
Abstract
OBJECTIVE This study evaluated the wear of an antagonist and friction and wear properties of dental zirconia ceramic that was subjected to microwave and conventional sintering methods. METHODS Ten specimens were fabricated from Lava brand zirconia and randomly assigned to microwave and conventional sintering groups. A profile tester for surface roughness was used to measure roughness of the specimens. Wear test was performed, and steatite ceramic was used as antagonist. Friction coefficient curves were recorded, and wear volume were calculated. Finally, optical microscope was used to observe the surface morphology of zirconia and steatite ceramics. Field emission scanning electron microscopy was used to observe the microstructure of zirconia. RESULTS Wear volumes of microwave and conventionally sintered zirconia were (6.940±1.382)×10⁻², (7.952±1.815) ×10⁻² mm³, respectively. Moreover, wear volumes of antagonist after sintering by the considered methods were (14.189±4.745)×10⁻², (15.813±3.481)×10⁻² mm³, correspondingly. Statistically significant difference was not observed in the wear resistance of zirconia and wear volume of steatite ceramic upon exposure to two kinds of sintering methods. Optical microscopy showed that ploughed surfaces were apparent in zirconia. The wear surface of steatite ceramic against had craze, accompanied by plough. Scanning electron microscopy showed that zirconia was sintered compactly when subjected to both conventional sintering and microwave methods, whereas grains of zirconia sintered by microwave alone were smaller and more uniform. CONCLUSIONS Two kinds of sintering methods are successfully used to produce dental zirconia ceramics with similar friction and wear properties.
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Affiliation(s)
- Hu Guoxin
- Fuzhou Medical College, Nanchang University, Fuzhou 344000, China
| | - Yang Ying
- Dept. of Prosthodontics, Affiliated Stomatological Hospital of Nanchang University, Nanchang 330006, China
| | - Jiang Yuemei
- Dept. of Prosthodontics, Affiliated Stomatological Hospital of Jiujiang University, Jiujiang 332000, China
| | - Xia Wenjing
- Dept. of Prosthodontics, Affiliated Stomatological Hospital of Nanchang University, Nanchang 330006, China
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Yuemei J, Ying Y, Wenhui Z, Guoxin H, Qiuxia Y. [Translucency of dental zirconia ceramics sintered in conventional and microwave ovens]. Hua Xi Kou Qiang Yi Xue Za Zhi 2015; 33:642-645. [PMID: 27051961 PMCID: PMC7030360 DOI: 10.7518/hxkq.2015.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/06/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To evaluate the effect of microwave sintering on the translucency of zirconia and to compare these effect with those of conventional sintering. The relationship between the microstructure of specimens and translucency was investigated. METHODS A total of 10 disc-shaped specimens were fabricated from 2 commercial brands of zirconia, namely, Zenostar and Lava. Each group included 5 discs. Conventional sintering was performed according to the manufacturers' specifications. The maximum temperature for Zenostar was 1,490 °C, whereas that for Lava was 1,500 °C. The dwelling time was 2 h. The sintering temperature for microwave sintering was 1,420 °C, heating rate was 15 °C · min⁻¹, and dwelling time was 30 min. After sintering, the translucency parameter (TP) of the specimens were measured with ShadeEye NCC. The sintered density of the specimens was determined by Archimedes' method. The grain size and microstructure of the specimens were investigated by scanning electron microscopy. RESULTS Density and translucency slightly increased by microwave sintering, but no significant difference was found between microwave and conventional sintering (P > 0.05). Small and uniform microstructure were obtained from microwave sintering. The mean TP of Lava was significantly higher than that of Zenostar (P < 0.001). CONCLUSION The translucency of zirconia sintered by microwave sintering is similar to that of the zirconia sintered by conventional sintering.
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