Liquid phase sintered SiC. Processing and transformation controlled microstructure tailoring

Autor(es)

V.A. Izhevskyi ^[1] ; L.A. Genova ^[2] ; A.H.A. Bressiani ^[3] ; J.C. Bressiani ^[4]

Afiliação do(s) autor(es)

^[1] Instituto de Pesquisas Energéticas e Nucleares - Brasil

^[2] Instituto de Pesquisas Energéticas e Nucleares - Brasil

^[3] Instituto de Pesquisas Energéticas e Nucleares - Brasil

^[4] Instituto de Pesquisas Energéticas e Nucleares - Brasil

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 3, n. 4, p. 131-138, 2000-10-00.
• Área do conhecimento: Engenharias - Engenharia de Materiais e Metalúrgica
• Assunto(s): Materiais não metálicos Materiais cerâmicos Refratários Sinterização

Resumo

Microstructure development and phase formation processes during sintering of silicon carbide based materials with AlN-Y2O3, AlN-Yb2O3, and AlN-La2O3 sintering additives were investigated. Densification of the materials occurred by liquid-phase sintering mechanism. Proportion of alpha- and beta-SiC powders in the initial mixtures was a variable parameter, while the molar ratio of AlN/RE2O3, and the total amount of additives (10 vol. %) were kept constant. Shrinkage behavior during sintering in interrelation with the starting composition of the material and the sintering atmosphere was investigated by high temperature dilatometry. Kinetics of b-SiC to a-SiC phase transformation during post-sintering heat treatment at temperatures 1900-1950 °C was studied, the degree of phase transformation being determined by quantitative x-ray analysis using internal standard technique. Evolution of microstructure resulting from beta-SiC to alpha-SiC transformation was followed up by scanning electron microscopy on polished and chemically etched samples. Transformation-controlled grain growth mechanism similar to the one observed for silicon nitride based ceramics was established. Possibility of in-situ platelet reinforced dense SiC-based ceramics fabrication with improved mechanical properties by means of sintering was shown. (AU)

• Processo FAPESP: 97/01114-5 - Estudo sistêmico para o desenvolvimento de concretos refratários avançados
• Beneficiário: Victor Carlos Pandolfelli
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 96/09604-9 - Laboratório de análise de materiais cerâmicos, metálicos e compósitos por difração de Raios X
• Beneficiário: Reginaldo Muccillo
• Modalidade de apoio: Auxílio à Pesquisa - Programa Infraestrutura - Equipamentos