Journal ArticleDOI
High temperature thermal expansion of mullite: an in situ neutron diffraction study up to 1600°C
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TLDR
In this article, the authors measured the thermal expansion of undoped and Cr-doped 3/2 mullites (10.8 wt.% Cr2O3) with in situ neutron and X-ray synchrotron (25-1000°C) diffraction techniques.Abstract:
Structural thermal expansions of undoped and Cr-doped 3/2 mullites (10.8 wt.% Cr2O3) were measured with in situ neutron (25–1600°C) and X-ray synchrotron (25–1000°C) diffraction techniques. Heat treatments between 25 and 300°C cause little and non-linear structural expansions. Above 300°C and up to 1000°C the mullites display linear and low increase of the lattice constants. The mean values of undoped mullite are slightly higher ( α av ≈ 5.45×10−6) than those of Cr-doped mullite ( α av ≈ 4.95×10−6), thus confirming earlier in situ high-temperature diffraction data. Above about 1000°C the expansion behaves discontinuously. Structural expansions of undoped and Cr-doped mullite strongly increase yielding similar mean expansion coefficients ( α av ≈ 7.50×10−6) for both materials. The highest increase of lattice constants has been determined in b axis direction throughout 1600°C in undoped and Cr-doped mullite. High temperature diffraction studies under heating-up and cooling-down conditions yielded reversible expansion effects, including the anomalous behaviour at about 1000°C.read more
Citations
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Ceramic materials for thermal barrier coatings
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Journal ArticleDOI
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.
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Ultra-low thermal conductivity thermal barrier coatings from recycled fly-ash cenospheres
TL;DR: In this paper, the authors measured the thermal conductivity of electrophoretically deposited fly ash (FA) and fly-ash cenosphere (FAC) coatings in the range 100-500k by the 3ω method.
Journal ArticleDOI
Microstructural and thermal properties of plasma sprayed mullite coatings
TL;DR: In this paper, a mixture of crystalline and amorphous phases of 3Al 2 O 3 -2SiO 2 was fabricated by atmospheric plasma spraying, and the porosity of as-sprayed coating was in the range between 2 and 3% and substantially remained unchanged after thermal treatment.
Journal ArticleDOI
Elastic Properties of Mullite Single Crystals up to 1400°C
TL;DR: In this paper, the authors measured the elastic constants and their temperature derivatives of orthorhombic 2/1-mullite single crystals using resonant and ultrasonic spectroscopy between ambient temperature and 14001C in air.
References
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Journal ArticleDOI
High temperature crystal structure of a 3:2 mullite from neutron diffraction data
TL;DR: In this article, high temperature neutron investigations up to 1950 K of 3:2-sintered mullite show a smooth reversible behaviour which can be described by a rotation of more or less rigid TO4 (T = Al(2),Si)-tetrahedra and accompanying distortions of the Al(1)O6-octahedra.
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Thermal Expansion Discontinuities of Mullite
TL;DR: In this paper, the authors used 3/2-type fused-mullite single crystals to measure the thermal expansion of a, b, and c axes and found that the slopes of a and volume expansion curves are higher above the expansion discontinuity than below.
Journal ArticleDOI
Sintering and Mechanical Properties of Yttria‐Doped Tetragonal ZrO2 Polycrystal/Mullite Composites
TL;DR: In this article, a tetragonal ZrO/sub 2/polycrystal (Y-TZP)/mullite composite was sintered at 1450/sup 0/ to 1500/Sup 0/C in air to disperse rod-like mullite grains at the grain boundary of Y-ZP and the mechanical and thermal properties were investigated.