1
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Fomenko EV, Rogovenko ES, Anshits NN, Solovyov LA, Anshits AG. Characterization of Silicate Glass/ Mullite Composites Based on Coal Fly Ash Cenospheres as Effective Gas Separation Membranes. Materials (Basel) 2023; 16:6913. [PMID: 37959509 PMCID: PMC10649462 DOI: 10.3390/ma16216913] [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: 09/22/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023]
Abstract
Membrane technology is a promising method for gas separation. Due to its low energy consumption, environmental safety, and ease of operation, membrane separation has a distinct advantage over the cryogenic distillation conventionally used to capture light inert gases. For efficient gas recovery and purification, membrane materials should be highly selective, highly permeable, thermally stable, and low-cost. Currently, many studies are focused on the development of high-tech materials with specific properties using industrial waste. One of the promising waste products that can be recycled into membrane materials with improved microstructure is cenospheres-hollow aluminosilicate spherical particles that are formed in fly ash from coal combustion during power generation. For this purpose, based on narrow fractions of fly ash cenospheres containing single-ring and network structure globules, silicate glass/mullite composites were prepared, characterized, and tested for helium-neon mixture separation. The results indicate that the fragmented structure of the cenosphere shells with areas enriched in SiO2 without modifier oxides, formed due to the crystallization of defective phases of mullite, quartz, cristobalite, and anorthite, significantly facilitates the gas transport process. The permeability coefficients He and Ne exceed similar values for silicate glasses; the selectivity corresponds to a high level even at a high temperature: αHe/Ne-22 and 174 at 280 °C.
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Affiliation(s)
- Elena V. Fomenko
- Institute of Chemistry and Chemical Technology, Federal Research Center “Krasnoyarsk Science Center of Siberian Branch of the Russian Academy of Sciences”, Akademgorodok 50/24, 660036 Krasnoyarsk, Russia; (E.S.R.); (N.N.A.); (L.A.S.); (A.G.A.)
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2
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Nevřivová L, Zemánek D. Study of the Mineralogical Composition of an Alumina-Silica Binder System Formed by the Sol-Gel Method. Materials (Basel) 2023; 16:5466. [PMID: 37570170 PMCID: PMC10420114 DOI: 10.3390/ma16155466] [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: 06/30/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023]
Abstract
Colloidal bonds are realized by sol-gel technology. The binder system of the refractory castable belongs to the Al2O3-SiO2 binary diagram. Mullite is the most thermally stable mineral in this system. This work was motivated by an attempt to maximize the mullite content in the NCC binder system, because a high content of mullite is a guarantee of the long service life of refractories. Initially, the mineralogical composition of the pure gel was tested after drying and firing at temperatures between 1000 °C and 1600 °C. The behavior of the gel during drying was described. Subsequently, a method of minimizing gel shrinkage during drying was sought. To this aim, fine fillers (microfillers) of alumina and silica were tested. In particular, the reactivity of the microfillers, the ability of the microfillers to react with the sol to form mullite, and the drying shrinkage of the microfiller-doped gel were evaluated. The study showed that the least suitable source of Al2O3 in terms of its reactivity is tabular corundum, which produces the lowest amount of mullite. The internal structure of the prepared binder system when using different microfillers was described. Based on the results from the second stage of the work, several complete matrixes of the binder system were designed and the degree of their mullitization at different firing temperatures was studied. During this stage, it was shown that the degree of mullitization of the binder system depends mainly on the microsilica content. In the binder system, the maximum mullite content recorded was 76%. The effect of amorphous SiO2 on the bulk density and internal structure of the binder system was also described.
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Affiliation(s)
| | - David Zemánek
- Faculty of Civil Engineering, Brno University of Technology, Veveri 331/95, 602 00 Brno, Czech Republic;
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3
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Mahnicka-Goremikina L, Svinka R, Svinka V, Goremikins V, Ilic S, Grase L, Juhnevica I, Rundans M, Eiduks TV, Pludons A. Porous Mullite Ceramic Modification with Nano-WO 3. Materials (Basel) 2023; 16:4631. [PMID: 37444944 DOI: 10.3390/ma16134631] [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: 05/23/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 07/15/2023]
Abstract
Mullite and mullite-alumina ceramics materials with dominance of the mullite phase are used in different areas of technology and materials science. Porous mullite ceramics materials can be used simultaneously as refractory heat insulators and also as materials for constructional elements. The purpose of this work was to investigate the WO3 nanoparticle influence on the evolution of the aluminum tungstate and zircon crystalline phases in mullite ceramics due to stabilization effects caused by different microsize ZrO2 and WO3. The use of nano-WO3 prevented the dissociation of zircon in the ceramic samples with magnesia-stabilized zirconia (MSZ), increased porosity by approximately 60 ± 1%, increased the intensity of the aluminum tungstate phase, decreased bulk density by approximately 1.32 ± 0.01 g/cm3, and increased thermal shock resistance by ensuring a loss of less than 5% of the elastic modulus after 10 cycles of thermal shock.
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Affiliation(s)
- Ludmila Mahnicka-Goremikina
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Ruta Svinka
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Visvaldis Svinka
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Vadims Goremikins
- Institute of Structural Engineering and Reconstruction, Riga Technical University, Kipsalas st. 6A, LV-1048 Riga, Latvia
| | - Svetlana Ilic
- Department of Materials, Vinča Institute of Nuclear Sciences-National Institute of Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, P.O. Box 522, 11001 Belgrade, Serbia
| | - Liga Grase
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Inna Juhnevica
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Maris Rundans
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Toms Valdemars Eiduks
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
| | - Arturs Pludons
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena st. 3/7, LV-1048 Riga, Latvia
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4
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Yang J, Zhao L, Zhou T, Ma S, Wang X. Catalytic Oxidation Activity of NO over Mullite-Supported Amorphous Manganese Oxide Catalyst. Materials (Basel) 2023; 16:ma16103821. [PMID: 37241448 DOI: 10.3390/ma16103821] [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: 04/09/2023] [Revised: 05/10/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023]
Abstract
Nitric oxide (NO) can pose a severe threat to human health and the environment. Many catalytic materials that contain noble metals can oxidize NO into NO2. Therefore, the development of a low-cost, earth-abundant, and high-performance catalytic material is essential for NO removal. In this study, mullite whiskers on a micro-scale spherical aggregate support were obtained from high-alumina coal fly ash using an acid-alkali combined extraction method. Microspherical aggregates and Mn(NO3)2 were used as the catalyst support and the precursor, respectively. A mullite-supported amorphous manganese oxide (MSAMO) catalyst was prepared by impregnation and calcination at low temperatures, in which amorphous MnOx is evenly dispersed on the surface and inside of aggregated microsphere support. The MSAMO catalyst, with a hierarchical porous structure, exhibits high catalytic performance for the oxidation of NO. The MSAMO catalyst, with a 5 wt% MnOx loading, presented satisfactory NO catalytic oxidation activity at 250 °C, with an NO conversion rate as high as 88%. Manganese exists in a mixed-valence state in amorphous MnOx, and Mn4+ provides the main active sites. The lattice oxygen and chemisorbed oxygen in amorphous MnOx participate in the catalytic oxidation of NO into NO2. This study provides insights into the effectiveness of catalytic NO removal in practical industrial coal-fired boiler flue gas. The development of high-performance MSAMO catalysts represents an important step towards the production of low-cost, earth-abundant, and easily synthesized catalytic oxidation materials.
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Affiliation(s)
- Jianlin Yang
- College of Materials Science and Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Lu Zhao
- College of Materials Science and Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Tianran Zhou
- School of Civil Engineering, Liaoning Technical University, Fuxin 123000, China
| | - Shuhua Ma
- CAS Key Laboratory for Green Processes and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Wang
- CAS Key Laboratory for Green Processes and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
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Lin SM, Yu YL, Zhong MF, Yang H, Liu Y, Li H, Zhang CY, Zhang ZJ. Preparation of Anorthite/ Mullite In Situ and Phase Transformation in Porcelain. Materials (Basel) 2023; 16:1616. [PMID: 36837244 PMCID: PMC9968105 DOI: 10.3390/ma16041616] [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: 12/26/2022] [Revised: 01/30/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
A high sintering temperature is required to acquire excellent performance in the production of porcelain but results in high fuel consumption. To prepare the porcelain with outstanding performance at a lower temperature, a self-produced additive containing calcium (CaK) was added into a three-component system of kaolinite-feldspar-quartz. XRD and SEM were used to characterize the samples. The toughening mechanism and Gibbs free energy were investigated. After introducing the CaK, the bending strength of the porcelain fired at 1513 K increased from 56.32 ± 0.65 MPa to 95.31 ± 0.63 MPa, which was 21.83% higher than that of the porcelain without CaK at an optimal firing temperature of 1603 K. The main crystal phase of the sample comprised mullite and quartz in the raw materials at 1453~1603 K. The anorthite was observed at 1453 K and interlocked with needle-shaped mullite at 1513 K in the porcelain after adding CaK, which resulted in the higher bending strength. Quantitative analysis indicated that the amount of anorthite decreased at 1513 K and disappeared at 1543 K; the amount of mullite increased with temperature. The Gibbs free energy of the reaction (CaO•Al2O3•2SiO2 + 2(Al2O3•2SiO2) → 3Al2O3•2SiO2 + CaO + 4SiO2) at high temperature was negative, which suggested that the formation of mullite (3Al2O3•2SiO2) from anorthite (CaO•Al2O3•2SiO2) was possible. These findings implied that the addition of CaK contributed to the appropriate phase composition and microstructure, and the excellent performance of the porcelain at a lower temperature. In addition, the transformation between anorthite and mullite was possible in the special raw material system. The results are of interest in producing anorthite/mullite ceramics at reduced sintering temperatures and the conversion between anorthite and mullite.
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Affiliation(s)
- Shao-Min Lin
- School of Materials Science and Engineering, Hanshan Normal University, Chaozhou 521041, China
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
| | - Ya-Ling Yu
- School of Materials Science and Engineering, Hanshan Normal University, Chaozhou 521041, China
| | - Ming-Feng Zhong
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
| | - Huan Yang
- School of Materials Science and Engineering, Hanshan Normal University, Chaozhou 521041, China
| | - Yang Liu
- Chaozhou Three-Circle (Group) Co., Ltd., Chaozhou 515646, China
| | - Hang Li
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
| | - Chen-Yang Zhang
- School of Materials Science and Engineering, Hanshan Normal University, Chaozhou 521041, China
- School of Materials Science and Engineering, Central South University, Changsha 410083, China
| | - Zhi-Jie Zhang
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
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6
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Ji Q, Zhang L, Jiao X, Chen D. Alpha Al 2O 3 Nanosheet-Based Biphasic Aerogels with High-Temperature Resistance up to 1600 °C. ACS Appl Mater Interfaces 2023; 15:6848-6858. [PMID: 36693011 DOI: 10.1021/acsami.2c20272] [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] [Indexed: 06/17/2023]
Abstract
Alumina aerogels are desirable for lightweight and highly efficient thermal insulation. However, they are typically constrained by brittleness and structural collapse at high temperatures. The manufacture of alumina aerogels with ultralow thermal conductivity and excellent thermal stability at high temperatures beyond 1300 °C is still challenging. Herein, alumina aerogels with superior ultrahigh-temperature-resistant and thermal insulation were successfully prepared by assembling the α-Al2O3 nanosheets with silica sols as the high-temperature binders. Benefiting from the generation of the mullite-covered alumina biphasic structure, the α-Al2O3 nanosheet-based aerogels (ANSAs) exhibit excellent thermal and chemical stabilities even after calcination at as high as 1600 °C. The ANSAs had a low thermal conductivity (0.029 W·m-1·K-1 at room temperature), structural stability with a measured compressive strength of 0.6 MPa, and good thermal shock resistance. Furthermore, the 2D α-alumina@mullite core-shell sheets were also prepared as assembly units to construct aerogels (AMSAs). This core-shell structure can improve temperature resistance through inter-lattice suppression under continuous energy input at high temperatures. The AMSAs have a linear shrinkage of only 2.7% after calcination at 1600 °C for 30 min, further improving the temperature resistance, making them an ideal super-insulating material for applications at extremely high temperatures.
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Affiliation(s)
- Qiyan Ji
- National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P.R. China
| | - Li Zhang
- National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P.R. China
| | - Xiuling Jiao
- National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P.R. China
| | - Dairong Chen
- National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P.R. China
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Li X, Niu S, Wang D, Li J, Jiao Q, Guo X, Xu X. Microstructure and Crystallization Kinetics of Silica-Based Ceramic Cores with Enhanced High-Temperature Property. Materials (Basel) 2023; 16:606. [PMID: 36676341 PMCID: PMC9865690 DOI: 10.3390/ma16020606] [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: 12/01/2022] [Revised: 01/01/2023] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Silica-based ceramic cores play key roles in the casting of aeroengine blades, but they are highly limited by the poor high-temperature mechanical property. Here, fused mullite (FM) and sintered mullite (SM) powders were modified in silica-based ceramic cores, and the microstructure evolution and crystallization kinetics of ceramic cores depending on mullite types were studied. The ceramic cores with FM showed a dense microstructure and superior mechanical properties compared to those with SM. The ceramic cores with 10 wt.% of FM showed a crystallization activation energy of 1119.5 kJ/mol and a crystallization exponent of 1.74, and the values of 938.4 kJ/mol and 1.86 as SM were employed; the decreased crystallization activation energy and the elevated crystallization exponent by SM suggested that the excess impurities of alkali oxides and alkaline-earth oxides significantly promoted the crystallization of cristobalite. Even though the ceramic cores with mullite powders decreased slightly in the room-temperature mechanical property, their high-temperature flexure strength and creep deformation resistance were enhanced. The ceramic cores with 10 wt.% of FM showed excellent comprehensive performance, with linear shrinkage of 0.69%, room-temperature strength of 18.9 MPa, and high-temperature strength of 15.5 MPa, which satisfied the demands for hollow-blade casting.
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Affiliation(s)
- Xin Li
- Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
| | - Shuxin Niu
- Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
| | - Dongsheng Wang
- Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
| | - Jie Li
- School of Materials Science & Engineering, Chang’an University, Xi’an 710061, China
| | - Qi Jiao
- Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
| | - Xinlong Guo
- Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
| | - Xiqing Xu
- School of Materials Science & Engineering, Chang’an University, Xi’an 710061, China
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Conte S, Molinari C, Ardit M, Cruciani G, Dondi M, Zanelli C. Porcelain versus Porcelain Stoneware: So Close, So Different. Sintering Kinetics, Phase Evolution, and Vitrification Paths. Materials (Basel) 2022; 16:171. [PMID: 36614511 PMCID: PMC9821833 DOI: 10.3390/ma16010171] [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: 12/01/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Five porcelain and porcelain stoneware bodies were investigated to compare sintering mechanisms and kinetics, phase and microstructure evolution, and high temperature stability. All batches were designed with the same raw materials and processing conditions, and characterized by optical dilatometry, XRF, XRPD-Rietveld, FEG-SEM and technological properties. Porcelain and porcelain stoneware behave distinctly during sintering, with the convolution of completely different phase evolution and melt composition/structure. The firing behavior of porcelain is essentially controlled by microstructural features. Changes in mullitization create conditions for a relatively fast densification rate at lower temperature (depolymerized melt, lower solid load) then to contrast deformations at high temperature (enhanced effective viscosity by increasing solid load, mullite aspect ratio, and melt polymerization). In porcelain stoneware, the sintering behavior is basically governed by physical and chemical properties of the melt, which depend on the stability of quartz and mullite at high temperature. A buffering effect ensures adequate effective viscosity to counteract deformation, either by preserving a sufficient skeleton or by increasing melt viscosity if quartz is melted. When a large amount of soda-lime glass is used, no buffering effect occurs with melting of feldspars, as both solid load and melt viscosity decrease. In this batch, the persistence of a feldspathic skeleton plays a key role to control pyroplasticity.
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Affiliation(s)
- Sonia Conte
- CNR-ISSMC, Institute of Science, Technology and Sustainability for Ceramics, 48018 Faenza, Italy
| | - Chiara Molinari
- CNR-ISSMC, Institute of Science, Technology and Sustainability for Ceramics, 48018 Faenza, Italy
| | - Matteo Ardit
- Department Physics and Earth Sciences, University of Ferrara, 44122 Ferrara, Italy
| | - Giuseppe Cruciani
- Department Physics and Earth Sciences, University of Ferrara, 44122 Ferrara, Italy
| | - Michele Dondi
- CNR-ISSMC, Institute of Science, Technology and Sustainability for Ceramics, 48018 Faenza, Italy
| | - Chiara Zanelli
- CNR-ISSMC, Institute of Science, Technology and Sustainability for Ceramics, 48018 Faenza, Italy
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Mahnicka-Goremikina L, Svinka R, Svinka V, Grase L, Juhnevica I, Rundans M, Goremikins V, Tolendiuly S, Fomenko S. Thermal Properties of Porous Mullite Ceramics Modified with Microsized ZrO 2 and WO 3. Materials (Basel) 2022; 15:ma15227935. [PMID: 36431421 PMCID: PMC9694335 DOI: 10.3390/ma15227935] [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] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 05/17/2023]
Abstract
Mullite ceramics are well known as materials with a high temperature stability, strength and creep resistance. In this research, the effect of a modification with magnesia-stabilized zirconia and yttria-stabilized zirconia, separately, as well as in a mixture with WO3, in 1:1 and 1:2 ratios on the thermal properties of porous mullite ceramics was investigated. The porous mullite-containing ceramics were prepared by a slip casting of the concentrated slurry of raw materials with the addition of a suspension of Al paste for the pore formation due to the H2 evolution as a result of the reaction of Al with water. The formed samples were sintered at 1600 °C and the holding time was 1 h. The materials were characterized using X-ray diffractometry, scanning electron microscopy, mercury porosimetry, the laser flash contactless method, thermal shock resistance testing and the non-destructive impulse excitation method for determining the elasticity modulus. The modification of the porous mullite ceramic with a mixture of ZrO2 and WO3 oxides had a positive effect by decreasing the thermal conductivity, due to the increased porosity, in comparison to the undoped samples and samples with only ZrO2. The doubling of the WO3 amount in the modifying oxide mixtures improved the ceramic thermal shock resistance. The porous mullite ceramics which were modified with magnesia-stabilized zirconia (2.8 mol% MgO) and WO3 had a lower thermal conductivity and improved thermal shock resistance than the samples with yttria-stabilized zirconia (8 mol% Y2O3) and WO3.
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Affiliation(s)
- Ludmila Mahnicka-Goremikina
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
- Correspondence:
| | - Ruta Svinka
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
| | - Visvaldis Svinka
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
| | - Liga Grase
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
| | - Inna Juhnevica
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
| | - Maris Rundans
- Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena St. 3/7, LV-1048 Riga, Latvia
| | - Vadims Goremikins
- Institute of Structural Engineering and Reconstruction, Riga Technical University, Kipsalas St. 6A, LV-1048 Riga, Latvia
| | - Sanat Tolendiuly
- Space Engineering Department, AUPET Named G. Daukeev, Baitursynov St., 126/1, Almaty 050013, Kazakhstan
| | - Sergey Fomenko
- Institute of Combustion Problems, Bogenbay Batyr St. 172, Almaty 050012, Kazakhstan
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Yang HL, Li ZS, Ding YD, Ge QQ, Shi YJ, Jiang L. Effect of Silicon Source (Fly Ash, Silica Dust, Gangue) on the Preparation of Porous Mullite Ceramics from Aluminum Dross. Materials (Basel) 2022; 15:ma15207212. [PMID: 36295282 PMCID: PMC9612259 DOI: 10.3390/ma15207212] [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] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 06/02/2023]
Abstract
Aluminum dross (AD) is a waste product produced during aluminum processing and can be used to prepare mullite ceramic materials. However, the research on the preparation of mullite porous ceramics entirely from solid waste is still in the development stage. In this paper, porous mullite ceramics were successfully fabricated using a solid-phase sintering process with AD and different silicon sources (fly ash, silica dust, and gangue) as raw materials. The bulk density, apparent porosity, and compressive strength of the specimens were obtained, and the phase compositions and microstructures of the sintered specimens were measured using XRD and SEM, respectively. The average activation energy of the phase transition of fly ash, silica dust, and gangue as silicon sources were 984 kJ/mol, 1113 kJ/mol, and 741 kJ/mol, respectively. The microstructures of the mullite in the specimens were prisms, random aggregates, and needle-shaped, respectively. The formation of needle-shaped mullite combined with the substrate enhanced the mechanical strength of the porous mullite ceramics. The apparent porosity, density, and compressive strength of the specimens with gangue as the silicon source were 33.13%, 1.98 g/cm3, and 147.84 MPa, respectively, when sintered at 1300 °C for 2 h.
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Affiliation(s)
- Hong-Liang Yang
- Key Laboratory for Ecological Metallurgy of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - Zi-Shen Li
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - You-Dong Ding
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - Qi-Qi Ge
- School of Metallurgy, Northeastern University, Shenyang 110819, China
| | - Yu-Juan Shi
- Northeastern University Engineering & Research Institute Co., Ltd., Shenyang 110819, China
| | - Lan Jiang
- Key Laboratory for Ecological Metallurgy of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China
- School of Metallurgy, Northeastern University, Shenyang 110819, China
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Lowry B, Louden A, Jerman R, Pyatina T. Corrosion-Resistant Plug Materials for Geothermal Well Fluid Control. Materials (Basel) 2022; 15:6703. [PMID: 36234060 PMCID: PMC9572571 DOI: 10.3390/ma15196703] [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: 09/09/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Conventional cements and plugs are challenged by corrosion in CO2-rich and extreme geothermal environments, due to the hostile chemistry and high temperatures. Thermite-based sealing and well intervention technologies are being applied in the oil and gas industry, combining the energy delivery capability of thermite materials with the sealing characteristics of low melt temperature alloys. The thermite reaction products (ceramics) and the sealing alloys used in these plugs both have very attractive corrosion properties, and their operating envelopes extend into geothermal conditions. Thermite plugs and platforms, without supplemental sealing materials, have been considered for nuclear waste isolation, carbon sequestration, and geothermal applications due to the geochemical stability of the ceramic product and its very high service temperature. This study addresses corrosion resistance of the thermite reaction products. A range of engineered thermite systems which yield thermite reaction products including pure aluminum oxide, feldspar, or aluminosilicate solid solutions (in addition to the iron produced in thermite reactions) was developed. These materials were evaluated for their strong acid resistance (pH 1), carbonate resistance (sodium carbonate) and thermal shock resistance (600 °C heating → cold water quenching repeated three times). Performance of different materials was evaluated based on the changes in mechanical properties, water-fillable porosity, phase changes under stress conditions. The aluminosilicate product exhibited very good corrosion resistance, both from material loss and strength perspectives, while the other products performed with varying degrees of stability. This paper presents the results of the thermite corrosion studies and describes the novel tools being deployed, and under development, to satisfy challenging barrier and intervention applications.
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Affiliation(s)
- Bill Lowry
- isol8 Inc., Port Townsend, WA 98368-9305, USA
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Krzysiak Z, Gevorkyan E, Nerubatskyi V, Rucki M, Chyshkala V, Caban J, Mazur T. Peculiarities of the Phase Formation during Electroconsolidation of Al 2O 3-SiO 2-ZrO 2 Powders Mixtures. Materials (Basel) 2022; 15:6073. [PMID: 36079454 PMCID: PMC9457512 DOI: 10.3390/ma15176073] [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] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
This paper is devoted to the sintering process of Al2O3-SiO2-ZrO2 ceramics. The studied method was electroconsolidation with directly applied electric current. This method provides substantial improvements to the mechanical properties of the sintered samples compared to the traditional sintering in the air. The research covered elemental and phase analysis of the samples, which revealed phase transition of high-alumina solid solutions into mullite and corundum. Zirconia was represented mainly by tetragonal phase, but monoclinic phase was present, too. Electroconsolidation enabled samples to reach a density of 3.0 g/cm3 at 1300 °C, while the sample prepared by traditional sintering method obtained it only at 1700 °C. For the composite Al2O3-20 wt.% SiO2-10 wt.% ZrO2 fabricated by electroconsolidation, it was demonstrated that fracture toughness was higher by 20-30%, and hardness was higher by 15-20% compared to that of samples sintered traditionally. Similarly, the samples fabricated by electroconsolidation exhibited elastic modulus E higher by 15-20%. The hypothesis was proposed that the difference in mechanical and physical properties could be attributed to the peculiarities of phase formation processes during electroconsolidation.
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Affiliation(s)
- Zbigniew Krzysiak
- Faculty of Production Engineering, University of Life Sciences in Lublin, Głęboka 28, 20-612 Lublin, Poland
| | - Edwin Gevorkyan
- Wagon Engineering and Production Quality, Ukraine State University of Railway Transport, 7 Feuerbach Sq., 61010 Kharkiv, Ukraine
| | - Volodymyr Nerubatskyi
- Wagon Engineering and Production Quality, Ukraine State University of Railway Transport, 7 Feuerbach Sq., 61010 Kharkiv, Ukraine
| | - Mirosław Rucki
- Institute of Mechanical Science, Vilnius Gediminas Technical University, J. Basanaviciaus str. 28, LT-03224 Vilnius, Lithuania
| | - Volodymyr Chyshkala
- Department of Reactor Engineering Materials and Physical Technologies, V. N. Karazin Kharkiv National University, 4 Svobody Sq., 61022 Kharkiv, Ukraine
- Sieć Badawcza Łukasiewicz, Instytut Technologii Ekspoatacji w Radomiu, ul. K.Pułaskiego 6/10, 26-600 Radom, Poland
| | - Jacek Caban
- Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
| | - Tomasz Mazur
- Faculty of Mechanical Engineering, Kazimierz Pulaski University of Technology and Humanities in Radom, Stasieckiego 54, 26-600 Radom, Poland
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Hyun DE, Jeon JB, Lee YS, Kim YN, Kim M, Ko S, Koo SM, Shin WH, Park C, Lee DW, Oh JM. Fabrication of Large-Area Mullite-Cordierite Composite Substrates for Semiconductor Probe Cards and Enhancement of Their Reliability. Materials (Basel) 2022; 15:4283. [PMID: 35744342 DOI: 10.3390/ma15124283] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 05/23/2022] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 12/03/2022]
Abstract
This work aims to fabricate a large-area ceramic substrate for the application of probe cards. Mullite (M) and cordierite (C), which both have a low thermal expansion coefficient, excellent resistance to thermal shock, and high durability, were selected as starting powders. The mullite–cordierite composites were produced through different composition ratios of starting powders (M:C = 100:0, M:C = 90:10, M:C = 70:30, M:C = 50:50, M:C = 30:70, and M:C = 0:100). The effects of composition ratio and sintering temperature on the density, porosity, thermal expansion coefficient, and flexural strength of the mullite–cordierite composite pellets were investigated. The results showed that the mullite–cordierite composite pellet containing 70 wt% mullite and 30 wt% cordierite sintered at 1350 °C performed exceptionally well. Based on these findings, a large-area mullite–cordierite composite substrate with a diameter of 320 mm for use in semiconductor probe cards was successfully fabricated. Additionally, the changes in sheet resistance and flexural strength were measured to determine the effect of the environmental tests on the large-area substrate such as damp heat and thermal shock. The results indicated that the mullite–cordierite composite substrate was extremely reliable and durable.
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Sánchez-Soto PJ, Eliche-Quesada D, Martínez-Martínez S, Pérez-Villarejo L, Garzón E. Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering. Materials (Basel) 2022; 15:583. [PMID: 35057297 DOI: 10.3390/ma15020583] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 02/04/2023]
Abstract
A deposit of raw kaolin, located in West Andalusia (Spain), was studied in this work using a representative sample. The methods of characterization were X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis by sieving and sedimentation, and thermal analysis. The ceramic properties were determined. A sample of commercial kaolin from Burela (Lugo, Spain), with applications in the ceramic industry, was used in some determinations for comparison purposes. The kaolin deposit has been produced by alteration of feldspar-rich rocks. This raw kaolin was applied as an additive in local manufactures of ceramics and refractories. However, there is not previous studies concerning its characteristics and firing properties. Thus, the meaning of this investigation was to conduct a scientific study on this subject and to evaluate the possibilities of application. The raw kaolin was washed for the beneficiation of the rock using water to increase the kaolinite content of the resultant material. The results indicated that the kaolinite content of the raw material was 20 wt % as determined by XRD, showing ~23 wt % of particles lower than 63 µm. The kaolinite content of the fraction lower than 63 µm was 50 wt %. Thus, an improvement of the kaolinite content of this raw kaolin was produced by wet separation. However, the kaolin was considered as a waste kaolin, with microcline, muscovite and quartz identified by XRD. Thermal analyses by Thermo-Dilatometry (TD), Differential Thermal Analysis (DTA) and Thermo-Gravimetry (TG) allowed observe kaolinite thermal decomposition, quartz phase transition and sintering effects. Pressed samples of this raw kaolin, the fraction lower than 63 µm obtained by water washing and the raw kaolin ground using a hammer mill were fired at several temperatures in the range 1000–1500 °C for 2 h. The ceramic properties of all these samples were determined and compared. The results showed the progressive linear firing shrinkage by sintering in these samples, with a maximum value of ~9% in the fraction lower than 63 µm. In general, water absorption capacity of the fired samples showed a decrease from ~18–20% at 1050 °C up to almost zero after firing at 1300 °C, followed by an increase of the experimental values. The open porosity was almost zero after firing at 1350 °C for 2 h and the bulk density reached a maximum value of 2.40 g/cm3 as observed in the ground raw kaolin sample. The XRD examination of fired samples indicated that they are composed by mullite, from kaolinite thermal decomposition, and quartz, present in the raw sample, as main crystalline phases besides a vitreous phase. Fully-densified or vitrified materials were obtained by firing at 1300–1350 °C for 2 h. In a second step of this research, it was examined the promising application of the previous study to increase the amount of mullite by incorporation of alumina (α-alumina) to this kaolin sample. Firing of mixtures, prepared using this kaolin and α-alumina under wet processing conditions, produced the increase of mullite in relative proportion by reaction sintering at temperatures higher than 1500 °C for 2 h. Consequently, a mullite refractory can be prepared using this kaolin. This processing of high-alumina refractories is favoured by a previous size separation, which increases the kaolinite content, or better a grinding treatment of the raw kaolin.
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Shoppert A, Loginova I, Valeev D. Kinetics Study of Al Extraction from Desilicated Coal Fly Ash by NaOH at Atmospheric Pressure. Materials (Basel) 2021; 14:ma14247700. [PMID: 34947303 PMCID: PMC8707349 DOI: 10.3390/ma14247700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 11/01/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 11/16/2022]
Abstract
The most promising source of alumina in the 21st century is the coal fly ash (CFA) waste of coal-fired thermal plants. The methods of alumina extraction from CFA are often based on the pressure alkaline or acid leaching or preliminary roasting with different additives followed by water leaching. The efficiency of the alumina extraction from CFA under atmospheric pressure leaching is low due to the high content of acid-insoluble alumina phase mullite (3Al2O3·2SiO2). This research for the first time shows the possibility of mullite leaching under atmospheric pressure after preliminary desilication using high liquid to solid ratios (L:S ratio) and Na2O concentration. The analysis of the desilicated CFA (DCFA) chemical and phase composition before and after leaching has been carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The morphology and elemental composition of solid product particles has been carried out by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). An automated neural network and a shrinking core model (SCM) were used to evaluate experimental data. The Al extraction efficiency from DCFA has been more than 84% at T = 120 °C, leaching time 60 min, the L/S ratio > 20, and concentration of Na2O-400 g L-1. The kinetics analysis by SCM has shown that the surface chemical reaction controls the leaching process rate at T < 110 °C, and, at T > 110 °C after 15 min of leaching, the process is limited by diffusion through the product layer, which can be represented by titanium compounds. According to the SEM-EDX analysis of the solid residue, the magnetite spheres and mullite acicular particles were the main phases that remained after NaOH leaching. The spheric agglomerates of mullite particles with non-porous surface have also been found.
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Affiliation(s)
- Andrei Shoppert
- Department of Non-Ferrous Metals Metallurgy, Ural Federal University, 620002 Yekaterinburg, Russia;
- Correspondence:
| | - Irina Loginova
- Department of Non-Ferrous Metals Metallurgy, Ural Federal University, 620002 Yekaterinburg, Russia;
| | - Dmitry Valeev
- Laboratory of Sorption Methods, Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, 119991 Moscow, Russia;
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Ismail H, Azam F'A, Zainuddin Z, Bunawan H, Akbar MA, Mohamad H, Hamid MAA. Effects of Mullite, Maghemite, and Silver Nanoparticles Incorporated in β-Wollastonite on Tensile Strength, Magnetism, Bioactivity, and Antimicrobial Activity. Materials (Basel) 2021; 14:4643. [PMID: 34443166 DOI: 10.3390/ma14164643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/08/2021] [Accepted: 08/13/2021] [Indexed: 11/19/2022]
Abstract
β-wollastonite (βW) has sparked much interest in bone defect recovery and regeneration. Biomaterial-associated infections and reactions between implants with human cells have become a standard clinical concern. In this study, a green synthesized βW, synthesized from rice husk ash and a calcined limestone precursor, was incorporated with mullite, maghemite, and silver to produce β wollastonite composite (βWMAF) to enhance the tensile strength and antibacterial properties. The addition of mullite to the βWMAF increased the tensile strength compared to βW. In vitro bioactivity, antibacterial efficacy, and physicochemical properties of the β-wollastonite and βWMAF were characterized. βW and βWMAF samples formed apatite spherules when immersed in simulated body fluid (SBF) for 1 day. In conclusion, βWMAF, according to the tensile strength, bioactivity, and antibacterial activity, was observed in this research and appropriate for the reconstruction of cancellous bone defects.
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Synkiewicz-Musialska B, Szwagierczak D, Kulawik J, Pałka N, Piasecki P. Structural, Thermal and Dielectric Properties of Low Dielectric Permittivity Cordierite- Mullite-Glass Substrates at Terahertz Frequencies. Materials (Basel) 2021; 14:4030. [PMID: 34300949 DOI: 10.3390/ma14144030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 11/16/2022]
Abstract
Glass-ceramic composites containing cordierite, mullite, SiO2 glass and SiO2-B2O3-Al2O3-BaO-ZrO2 glass were fabricated in a process comprising solid state synthesis, milling, pressing and sintering. Thermal behavior, microstructure, composition and dielectric properties in the Hz-MHz, GHz and THz ranges were examined using a heating microscope, differential thermal analysis, thermogravimetry, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis, impedance spectroscopy, transmission method and time domain spectroscopy (TDS). The obtained substrates exhibited a low dielectric permittivity of 4.0-4.8. Spontaneously formed closed porosity dependent on the sintering conditions was considered as a factor that decreased the effective dielectric permittivity.
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Zemánek D, Lang K, Tvrdík L, Všianský D, Nevřivová L, Štursa P, Kovář P, Keršnerová L, Dvořák K. Development and Properties of New Mullite Based Refractory Grog. Materials (Basel) 2021; 14:ma14040779. [PMID: 33562214 PMCID: PMC7915343 DOI: 10.3390/ma14040779] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 12/21/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 11/25/2022]
Abstract
The presented study is focused on optimization and characterization of a high-alumina refractory aggregate based on natural raw materials—kaolins, claystone, and mullite dust by-product (used to increase the alumina and mullite contents, respectively). In total, four individual formulas with the Al2O3 contents between 45 and 50 wt.% were designed; the samples were subsequently fired, both in a laboratory oven and an industrial tunnel furnace. The effects of repeated firing were examined during industrial pilot tests. Mineral and chemical compositions and microstructures, of both the raw materials and designed aggregates, were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction, and optical and scanning electron microscopies. Porosity, mineral composition, and mullite crystal-size development during the firing process were also studied. Based on the acquired results, the formula with the perspective to be used as a new mullite grog, featuring similar properties as the available commercial products, however, with reduced production expenses, was selected. The quality of grog determines to a large extent the properties of the final product. Hence, optimization of aggregates for specific refractories is of a great importance. The production of engineered aggregates provides the opportunity to utilize industrial by-products.
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Affiliation(s)
- David Zemánek
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (D.Z.); (L.N.)
- P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; (K.L.); (L.T.); (P.Š.)
| | - Karel Lang
- P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; (K.L.); (L.T.); (P.Š.)
| | - Lukáš Tvrdík
- P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; (K.L.); (L.T.); (P.Š.)
| | - Dalibor Všianský
- Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 267/2, 602 00 Brno, Czech Republic; (D.V.); (P.K.); (L.K.)
| | - Lenka Nevřivová
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (D.Z.); (L.N.)
- P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; (K.L.); (L.T.); (P.Š.)
| | - Petr Štursa
- P-D Refractories CZ JSC, Nádražní 218, 679 63 Velké Opatovice, Czech Republic; (K.L.); (L.T.); (P.Š.)
- Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 267/2, 602 00 Brno, Czech Republic; (D.V.); (P.K.); (L.K.)
| | - Pavel Kovář
- Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 267/2, 602 00 Brno, Czech Republic; (D.V.); (P.K.); (L.K.)
| | - Lucie Keršnerová
- Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 267/2, 602 00 Brno, Czech Republic; (D.V.); (P.K.); (L.K.)
| | - Karel Dvořák
- Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic; (D.Z.); (L.N.)
- Correspondence: ; Tel.: +420-54114-7511 (ext. 8067)
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Figueirêdo JMR, Costa FPD, Fernandes JV, Rodrigues AM, Neves GA, Menezes RR, Santana LNL. Development of Scheelite Tailings-Based Ceramic Formulations with the Potential to Manufacture Porcelain Tiles, Semi-Stoneware and Stoneware. Materials (Basel) 2020; 13:E5122. [PMID: 33202868 DOI: 10.3390/ma13225122] [Citation(s) in RCA: 10] [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: 10/02/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 01/18/2023]
Abstract
New ceramic formulations based on scheelite tailing were developed, and their potential in the ceramic industry was evaluated. Green bodies with different contents of scheelite tailing (0–8 wt%) were sintered (1150 °C, 1200 °C, and 1250 °C) and characterized in terms of the main mineralogical phases, microstructure, and physico-mechanical properties. The mullite was the main phase identified in all sintered temperatures. This result was also ratified with the aid of scanning electron microscope (SEM) images, in which small needles of the mullite were detected. The presence of mullite is required because it contributes to increasing the mechanical resistance of the material. The physico-mechanical properties measured (water absorption, linear shrinkage, apparent porosity, and flexural strength) were compared to the ISO 13006, and the samples sintered at 1150 °C presented potential to be used as semi-stoneware, while those sintered at 1200 °C and 1250 °C can be employed stoneware and porcelain tiles, respectively.
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Barandehfard F, Aluha J, Hekmat-Ardakan A, Gitzhofer F. Improving Corrosion Resistance of Aluminosilicate Refractories towards Molten Al-Mg Alloy Using Non-Wetting Additives: A Short Review. Materials (Basel) 2020; 13:ma13184078. [PMID: 32937834 PMCID: PMC7560435 DOI: 10.3390/ma13184078] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/27/2020] [Accepted: 09/09/2020] [Indexed: 11/16/2022]
Abstract
The corrosion of refractories in contact with high temperature aluminum-magnesium alloys leads to contamination of the Al-Mg alloy products by solid impurities from degraded refractories. Where both the spinel and corundum phases form in the refractories, cracks are generated and propagated by diffusion of molten Al-Mg, resulting in severe corrosion. In this review paper, the corrosion phenomenon is discussed, and published work is summarized, supplemented by our recent experimental results. Using the Alcan immersion test, materials based on white-fused mullite (WFM) were evaluated for their corrosion resistance and interfacial behavior. WFM was modified using different 2-wt.% of non-wetting additives (NWAs), such as BaSO4, CaF2, Secar®71 cement and wollastonite to improve their performance when in contact with molten Al-Mg alloy at 850 °C for 96 h. The mechanical properties of the samples such as flexural and compressive strength were evaluated, in addition to X-ray diffraction and microscopic analysis (optical and scanning electron microscopy coupled with X-ray elemental mapping). It was observed that cracks formed in samples were promoted with only BaSO4, CaF2, Secar®71 cement or wollastonite. However, cracks did not appear in the sample promoted with both 1-wt.% CaF2 and 1-wt.% BaSO4, because of improved anti-wetting properties in addition to inhibiting spinel (MgAl2O4) formation, which is the main cause of the cracks. This is a significant finding in the prevention of cracks and improvement of the refractory corrosion resistance.
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Affiliation(s)
- Faranak Barandehfard
- Department of Chemical & Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (F.B.); (J.A.)
| | - James Aluha
- Department of Chemical & Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (F.B.); (J.A.)
| | | | - François Gitzhofer
- Department of Chemical & Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (F.B.); (J.A.)
- Correspondence: ; Tel.: +1-819-578-7937
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Xiao J, Chen W, Wei L, He W, Guo H. Mechanical Properties and Thermal Conductivity of Ytterbium-Silicate- Mullite Composites. Materials (Basel) 2020; 13:ma13030671. [PMID: 32028582 PMCID: PMC7040839 DOI: 10.3390/ma13030671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 12/27/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 11/16/2022]
Abstract
Various Ytterbium-Silicate-Mullite composites were successfully fabricated by adding Yb2SiO5 into mullite ceramics and then using pressureless sintering at 1550 °C. The influence of Yb2SiO5 addition on the microstructure, mechanical properties, and thermal conductivity of ytterbium-silicate-mullite composites was investigated. Results show that the composites mainly consisted of a mullite matrix and some in situ formed Yb2Si2O7 and Al2O3 phases. By the addition of Yb2SiO5, the Vickers hardness of composites reached ~9.0 at an additive concentration of 5 mol %. Fracture toughness increased to ~2.7 MPa·m1/2 at the additive concentration of 15 mol %, owing to the trans-granular fracture and crack deflection of the pinning effect of the Al2O3 phase in the composites. With the increase of the Al2O3 phase in the composite, the thermal conductivity for the 15YbAM reached around 4.0 W/(m·K) at 1200 °C. Although the thermal conductivity increased, it is still acceptable for such composites to be used as environmental barrier coatings.
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Affiliation(s)
- Jie Xiao
- School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191, China; (J.X.); (W.C.); (L.W.)
| | - Wenbo Chen
- School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191, China; (J.X.); (W.C.); (L.W.)
| | - Liangliang Wei
- School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191, China; (J.X.); (W.C.); (L.W.)
- Key Laboratory of High-temperature Structural Materials & Coatings Technology (Ministry of Industry and Information Technology), Beihang University, No. 37, Xueyuan Road, Beijing 100191, China
| | - Wenting He
- School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191, China; (J.X.); (W.C.); (L.W.)
- Correspondence: (W.H.); (H.G.); Tel.: +86-10-8231-7116 (H.G.)
| | - Hongbo Guo
- School of Materials Science and Engineering, Beihang University, No. 37, Xueyuan Road, Beijing 100191, China; (J.X.); (W.C.); (L.W.)
- Key Laboratory of High-temperature Structural Materials & Coatings Technology (Ministry of Industry and Information Technology), Beihang University, No. 37, Xueyuan Road, Beijing 100191, China
- Correspondence: (W.H.); (H.G.); Tel.: +86-10-8231-7116 (H.G.)
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Feng G, Jiang F, Hu Z, Jiang W, Liu J, Zhang Q, Hu Q, Miao L, Wu Q, Liang J. Pressure Field Assisted Polycondensation Nonaqueous Precipitation Synthesis of Mullite Whiskers and Their Application as Epoxy Resin Reinforcement. Polymers (Basel) 2019; 11:polym11122007. [PMID: 31817124 PMCID: PMC6960912 DOI: 10.3390/polym11122007] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 11/27/2019] [Accepted: 12/03/2019] [Indexed: 11/16/2022] Open
Abstract
Mullite whiskers were novelty prepared via pressure field assisted polycondensation nonaqueous precipitation method. The precipitate phase transition in heating process, phase compositions and microstructure of samples calcined at different temperatures, effect of pressure field on precursors polycondensation and AlF3 amount on sample morphology, the structure and the growth mechanism of whiskers were investigated. The results indicate that pressure field caused by kettle treatment promotes the polycondensation reaction between AlF3 and tetraethyl orthosilicate (TEOS), the excess aluminum fluoride coordinates with the precipitate skeleton of the =Al-O-Si≡, which brings about the low mullitization temperature (900 °C). The sample prepared with the optimal amount of aluminum fluoride (1.3 of the theoretical amount) calcined at 1100 °C presents high yield and aspect ratio (>15, 100 nm in diameter) of mullite whiskers. Growth of whiskers prepared via pressure field assisted polycondensation nonaqueous precipitation method is attributed to a vapor-solid (VS) mechanism with the inducement of screw. These mullite whiskers with the structure of multi-needle whiskers connected in the same center can be distributed evenly in epoxy resin, which greatly improves the mechanical properties of epoxy resin.
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Affiliation(s)
- Guo Feng
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
- Correspondence: (G.F.); (F.J.); (Z.H.); (W.J.)
| | - Feng Jiang
- Department of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333000, China;
- Correspondence: (G.F.); (F.J.); (Z.H.); (W.J.)
| | - Zi Hu
- Jiangxi Ceramic Research Institute, Jingdezhen 333000, China
- Correspondence: (G.F.); (F.J.); (Z.H.); (W.J.)
| | - Weihui Jiang
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
- Department of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333000, China;
- Correspondence: (G.F.); (F.J.); (Z.H.); (W.J.)
| | - Jianmin Liu
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
| | - Quan Zhang
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
| | - Qing Hu
- Department of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333000, China;
| | - Lifeng Miao
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
| | - Qian Wu
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
| | - Jian Liang
- National Engineering Research Center for Domestic & Builing Ceramics, Jingdezhen Ceramic Institute, Jingdezhen 333000, China; (J.L.); (Q.Z.); (L.M.); (Q.W.); (J.L.)
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Klar PB, Etxebarria I, Madariaga G. Characterizing modulated structures with first-principles calculations: a unified superspace scheme of ordering in mullite. Acta Crystallogr A Found Adv 2019; 75:260-272. [PMID: 30821259 PMCID: PMC6396396 DOI: 10.1107/s2053273319000846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/17/2019] [Indexed: 11/10/2022] Open
Abstract
The benefit of computational methods applying density functional theory for the description and understanding of modulated crystal structures is investigated. A method is presented which allows one to establish, improve and test superspace models including displacive and occupational modulation functions from first-principles calculations on commensurate structures. The total energies of different configurations allow one to distinguish stable and less stable structure models. The study is based on a series of geometrically optimized superstructures of mullite (Al4+2xSi2-2xO10-x) derived from the superspace group Pbam(α0½)0ss. Despite the disordered and structurally complex nature of mullite, the calculations on ordered superstructures are very useful for determining the ideal Al/Si ordering in mullite, extracting atomic modulation functions as well as understanding the SiO2-Al2O3 phase diagram. The results are compared with experimentally established models which confirm the validity and utility of the presented method.
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Affiliation(s)
- Paul Benjamin Klar
- Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apartado 644, Bilbao, 48080, Spain
| | - Iñigo Etxebarria
- Departamento de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apartado 644, Bilbao, 48080, Spain
| | - Gotzon Madariaga
- Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apartado 644, Bilbao, 48080, Spain
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24
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Ru J, Fan Y, Zhou W, Zhou Z, Wang T, Liu R, Yang J, Lu X, Wang J, Ji C, Wang L, Jiang W. Electrically Conductive and Mechanically Strong Graphene/ Mullite Ceramic Composites for High-Performance Electromagnetic Interference Shielding. ACS Appl Mater Interfaces 2018; 10:39245-39256. [PMID: 30346124 DOI: 10.1021/acsami.8b12933] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ceramic composites with good electrical conductivity and high strength that can provide electromagnetic interference (EMI) shielding are highly desirable for the applications in harsh environment. In this study, lightweight, highly conductive, and strong mullite composites incorporated with reduced graphene oxide (rGO) are successfully fabricated by spark plasma sintering at merely 1200 °C using the core-shell structured γ-Al2O3@SiO2 powder as a precursor. The transient viscous sintering induced by the γ-Al2O3@SiO2 precursor not only prohibits the reaction between mullite and rGO by greatly reducing the sintering temperature, but also induces a highly anisotropic structure in the rGO/mullite composite, leading to an extremely high in-plane electrical conductivity (696 S m-1 for only 0.89 vol % of rGO) and magnitude lower cross-plane electrical conductivity in the composites. As a result, very large loss tangent and EMI shielding effectiveness (>32 dB) can be achieved in the whole K band with extremely low rGO loading (less than 1 vol %), which is beneficial to maintain a good mechanical performance in ceramic matrix composites. Accordingly, the rGO/mullite composites show greatly improved strength and toughness when the rGO content is not high, which enables them to be applied as highly efficient EMI shielding materials while providing excellent mechanical performance.
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Affiliation(s)
| | | | - Weiwei Zhou
- Department of Materials Processing, Graduate School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | - Zhenxing Zhou
- Department of Materials Processing, Graduate School of Engineering , Tohoku University , Sendai 980-8579 , Japan
| | - Tuo Wang
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure , Shanghai Institute of Ceramics, Chinese Academy of Sciences , Shanghai 200050 , China
| | - Ruiheng Liu
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure , Shanghai Institute of Ceramics, Chinese Academy of Sciences , Shanghai 200050 , China
| | | | | | | | | | | | - Wan Jiang
- School of Material Science and Engineering , Jingdezhen Ceramic Institute , Jindezhen 333000 , China
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25
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Zhang Y, Zeng D, Wang B, Yang J. Effect of heating parameters on sintering behaviors and properties of mullite whisker frameworks. Nanotechnology 2018; 29:164001. [PMID: 29424705 DOI: 10.1088/1361-6528/aaae53] [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] [Indexed: 06/08/2023]
Abstract
Mullite whisker frameworks were fabricated by vapor-solid reaction with SiO2, Al2O3 and AlF3 powders as the whisker forming agent at high temperatures. The effects of heating temperature and soaking time on the weight loss, liner shrinkage, porosity, microstructure and compressive strength were investigated. The results showed that with the increasing of the sintering temperature and soaking time, the weight loss and liner shrinkage of the samples increased and the porosities decreased due to the accelerated vapor-solid reaction, resulting in strong bonding and grain growth of the mullite frameworks. The compressive strength of the samples increased with increasing the sintering temperature from 1500 to 1650°C, and decreased with the soaking time extended to more than 5 h for 1500°C and 2 h for 1650°C. A maximum compressive strength of 142 MPa at a porosity of 62.3% was obtained for the mullite whisker framework heated at 1500°C for 5 h. The enhanced strength was attributed to the strong bonding strength and fine mullite grains resulting from a relative lower heating temperature and a modest soaking time.
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Affiliation(s)
- Yaming Zhang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi, CHINA
| | - Dejun Zeng
- School of Material Science and Engineering, Chang'an University, Xian, Shaanxi, CHINA
| | - Bo Wang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, shaanxi, CHINA
| | - Jianfeng Yang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, shaanxi, CHINA
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Klar PB, de la Pinta N, Lopez GA, Etxebarria I, Breczewski T, Madariaga G. Ordered vacancy distribution in 2/1 mullite: a superspace model. Acta Crystallogr B Struct Sci Cryst Eng Mater 2017; 73:377-388. [PMID: 28572548 DOI: 10.1107/s2052520617001652] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/31/2017] [Indexed: 06/07/2023]
Abstract
A mullite single crystal with composition Al4.84Si1.16O9.58 (2) exhibiting sharp satellite reflections was investigated by means of X-ray diffraction. For the refinement of a superspace model in the superspace group Pbam(α0½)0ss different scale factors for main and satellite reflections were used in order to describe an ordered mullite structure embedded in a disordered polymorph. The ordered fraction of the mullite sample exhibits a completely ordered vacancy distribution and can be described as a block structure of vacancy blocks (VBs) that alternate with vacancy-free blocks (VFBs) along a and c. The incommensurate nature of mullite originates from a modulation of the block size, which depends on the composition. The displacive modulation is analyzed with respect to the vacancy distribution and a possible Al/Si ordering scheme is derived, although the measurement itself is not sensitive to the Al/Si distribution. An idealized, commensurate approximation for 2/1 mullite is also presented. Comparison of the ordered superspace model with different preceding models reconciles many key investigations of the last decades with partly contradicting conclusions, where mullite was usually treated as either ordered or disordered instead of considering simultaneously different states of order.
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Affiliation(s)
- Paul B Klar
- Dpto de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
| | - Noelia de la Pinta
- Dpto de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
| | - Gabriel A Lopez
- Dpto de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
| | - Iñigo Etxebarria
- Dpto de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
| | - Tomasz Breczewski
- Dpto de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
| | - Gotzon Madariaga
- Dpto de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, Apdo 644, Bilbao 48080, Spain
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Hosono H, Hayashi K, Kamiya T, Atou T, Susaki T. New functionalities in abundant element oxides: ubiquitous element strategy. Sci Technol Adv Mater 2011; 12:034303. [PMID: 27877391 PMCID: PMC5090463 DOI: 10.1088/1468-6996/12/3/034303] [Citation(s) in RCA: 13] [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] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/16/2011] [Accepted: 05/09/2011] [Indexed: 05/25/2023]
Abstract
While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth's crust), many advanced materials are based on rare elements. A 'rare-element crisis' is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a 'ubiquitous element strategy' for materials research, which aims to apply abundant elements in a variety of innovative applications. Creation of innovative oxide materials and devices based on conventional ceramics is one specific challenge. This review describes the concept of ubiquitous element strategy and gives some highlights of our recent research on the synthesis of electronic, thermionic and structural materials using ubiquitous elements.
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Affiliation(s)
- Hideo Hosono
- Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
- Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
- Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Katsuro Hayashi
- Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Toshio Kamiya
- Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
- Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Toshiyuki Atou
- Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Tomofumi Susaki
- Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama 226-8503, Japan
- Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
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28
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Paul KT, Satpathy SK, Manna I, Chakraborty KK, Nando GB. Preparation and Characterization of Nano structured Materials from Fly Ash: A Waste from Thermal Power Stations, by High Energy Ball Milling. Nanoscale Res Lett 2007. [PMCID: PMC3246387 DOI: 10.1007/s11671-007-9074-4] [Citation(s) in RCA: 27] [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: 05/04/2023]
Abstract
The Class F fly ash has been subjected to high energy ball milling and has been converted into nanostructured material. The nano structured fly ash has been characterized for its particle size by using particle size analyzer, specific surface area with the help of BET surface area apparatus, structure by X-ray diffraction studies and FTIR, SEM and TEM have been used to study particle aggregation and shape of the particles. On ball milling, the particle size got reduced from 60 μm to 148 nm by 405 times and the surface area increased from 0.249 m2/gm to 25.53 m2/gm i.e. by more than 100%. Measurement of surface free energy as well as work of adhesion found that it increased with increased duration of ball milling. The crystallite was reduced from 36.22 nm to 23.01 nm for quartz and from 33.72 nm to 16.38 nm for mullite during ball milling to 60 h. % crystallinity reduced from 35% to 16% during 60 h of ball milling because of destruction of quartz and hematite crystals and the nano structured fly ash is found to be more amorphous. Surface of the nano structured fly ash has become more active as is evident from the FTIR studies. Morphological studies revealed that the surface of the nano structured fly ash is more uneven and rough and shape is irregular, as compared to fresh fly ash which are mostly spherical in shape.
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Affiliation(s)
- K Thomas Paul
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
| | - SK Satpathy
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
| | - I Manna
- Metallurgical and Materials Engineering Department, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
| | - KK Chakraborty
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
| | - GB Nando
- Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
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