Journal ArticleDOI
Effect of Composition on Mullitization Behavior of α-Alumina/Silica Microcomposite Powders
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TLDR
In this article, the effect of composition on mullite formation was investigated using submicrometer composite particles that consisted of α-alumina cores and amorphous silica coatings.Abstract:
The effect of composition on mullite formation was investigated using submicrometer composite particles that consisted of α-alumina cores and amorphous silica coatings. Powders with varying alumina/silica ratios were prepared by varying the thickness of the silica coating. The mullitization behavior was monitored using differential thermal analysis, X-ray diffractometry, and scanning electron microscopy. The results were consistent with previous studies that indicated that mullite forms initially by nucleation and growth within the siliceous phase, but also that chemical interdiffusion within the mullite grains is required to complete the reaction. The reaction rate in both stages was affected by the alumina/silica ratio. Available evidence has indicated that the first stage of the reaction is controlled by the dissolution of alumina in the siliceous phase. Results for the second stage suggested that alumina diffuses more rapidly through mullite than silica.read more
Citations
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Mullite: Crystal Structure and Related Properties
TL;DR: In this article, a review of the state of the art on single crystal mullite is presented, focusing on the crystal structure of mullite and its properties, such as elasticity, compressibility, strength, toughness, creep and thermal properties.
Journal ArticleDOI
Oxidation bonding of porous silicon carbide ceramics
TL;DR: In this paper, an oxidation-bonding technique was successfully developed to fabricate porous SiC ceramics using the powder mixtures of SiC, Al2O3 and C.
Journal ArticleDOI
High‐Strength Porous Silicon Carbide Ceramics by an Oxidation‐Bonding Technique
TL;DR: In this paper, an oxidation-bonded SiC ceramics were fabricated by an oxidation bonding process in which the powder compacts are heated in air so that SiC particles are bonded to each other by oxidation-derived SiO2 glass.
Journal ArticleDOI
Characterization of high strength mortars with nano alumina at elevated temperatures
TL;DR: In this paper, the effect of elevated temperatures on chemical composition, microstructure and mechanical properties of high strength mortars with nano alumina was investigated and a brittleness index was defined.
Journal ArticleDOI
The Role of Intragranular Nanopores in Capacity Fade of Nickel-Rich Layered Li(Ni1–x–yCoxMny)O2 Cathode Materials
Shamail Ahmed,Anuj Pokle,Simon Schweidler,Andreas Beyer,Matteo Bianchini,Felix Walther,Andrey Mazilkin,Pascal Hartmann,Pascal Hartmann,Torsten Brezesinski,Jürgen Janek,Jürgen Janek,Kerstin Volz +12 more
TL;DR: High-resolution STEM demonstrates that nanopores are a source of intragranular cracking during cycling, and it is suggested that the presence of nanopores strongly affects the degradation of high-Ni NCM, as the pore surfaces apparently increase oxygen loss, rock salt regions, and strain-induced effects within the primary grains.
References
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Journal ArticleDOI
Stable and Metastable Equilibria in the System SiO2-Al2O3
I. A. Aksaf,Joseph A. Pask +1 more
TL;DR: In this paper, concentration profiles of Al/sub 2/O/sub 3/ in diffusion couples made from sapphire and fused silica were used to determine the stable equilibrium phase diagram of the system.
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Characterization of the Spinel Phase from SiO2-Al2O3 Xerogels and the Formation Process of Mullite
Kiyoshi Okada,Nozomu Ōtsuka +1 more
TL;DR: Two kinds of xerogels were prepared by slow and rapid hydrolyses of tetraethoxysilane and aluminum nitrate nonahydrate dissolved in ethanol as discussed by the authors.
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Revised Phase Diagram for the System Al2O3—SiO2
Shigeo Aramaki,Rustum Roy +1 more
TL;DR: In this article, the equilibrium diagram for the system A12O3-SiO2 has been revised based on 190 runs made up to 1860°C in sealed noble-metal containers.
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Diphasic xerogels, a new class of materials: phases in the system al2o3-sio2
TL;DR: In this paper, two series of xerogels (desiccated hydrogels), one consisting of single phases and the other of two phases, were prepared from organic and inorganic precursors in the system Al2o3-Sio2.
Journal ArticleDOI
Fabrication of Mullite and Mullite-Matrix Composites by Transient Viscous Sintering of Composite Powders
TL;DR: The transient viscous sintering (TVS) was used to fabricate mullite/zirconia/alumina composites as mentioned in this paper, which achieved densification at higher temperatures by reaction between the alumina and silica.