Mullite/SiAlON/alumina composites by infiltration processing

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb02799.x· OSTI ID:455162

Albano, M P; Scian, A N ^[1]

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1. Centro de Tecnologia de Recursos Minerales y Ceramica, Buenos Aires (Argentina)

The formation of mullite/SiAlON/alumina composites was studied by infiltrating a SiAlON/alumina-base composite with two different solutions, followed by thermal treatment. The base composite was prepared from a mixture of tabular Al{sub 2}O{sub 3} grains, fume SiO{sub 2}, and aluminum powders. The mixture was pressed into test bars and nitrided in a nitrogen-gas (N{sub 2}) atmosphere at 1,480 C. The infiltrants were prehydrolyzed ethyl polysilicate solution and ethyl polysilicate-aluminum nitrate solution. The composites were infiltrated under vacuum, cured at 100 C, and precalcined in air at 700 C. This infiltration process was repeated several times to produce bars that had been subjected to multiple infiltrations, then the bars were calcined in a N{sub 2} atmosphere at 1,480 C to obtain mullite/SiAlON/alumina composites. The infiltration process increased the percentage of nitrogenous crystalline and mullite phases in the matrix; therefore, a decrease of the composite microporosity was observed. The infiltration increased the mechanical strength of the composites. Of the two composites, the one produced using prehydrolyzed ethyl polysilicate as the infiltrant had a higher mechanical strength, before and after being subjected to a severe thermal shock.

• Sponsoring Organization: USDOE
• OSTI ID: 455162
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
EXPERIMENTAL DATA
FABRICATION
HEAT TREATMENTS
IMPREGNATION
MECHANICAL PROPERTIES
MULLITE
SILICATES
SILICON NITRIDES
SOLUTIONS
THERMAL SHOCK