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Santos, Carlos Augusto Xavier; Hayakawa, Motozo. 3Y-TZP/Si2N2O: composite obtained by pressureless sintering. In: CONGRESSO BRASILEIRO DE CERÂMICA, 43., CONGRESSO DE CERÂMICA DO MERCOSUL, 4., 1999, Florianópolis. Anais… Florianópolis, 1999.
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Número de Trabalhos: 2 (Nenhum com arquivo PDF disponível)
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Dados do autor na base InfoHab:
Número de Trabalhos: 1 (Nenhum com arquivo PDF disponível)
Citações: 1
Índice h: 1  
Co-autores: 10

Abstract

Y-TZP presents excellent properties at room temperature. These properties decrease as the temperature increases because high temperature acts negatively over the stress induced transformation toughening in the matrix. The addition of Si3N4 and SiC in a Y-TZP matrix is very interesting because leads to formation of silicon oxynitride and it increases the mechanical properties like toughness and hardness. Certainly the mechanical properties increment is limited by several difficulties which have appeared during processing and heating of these materials. This paper studies the behavior of the YTZP/ Si2N2O composite under different conditions of processing and sintering, showing the behavior of 20vol%Si3N4-SiC when added in YTZP matrix and heated under no pressure system. Al2O3 and Y2O3 were used to maintain the stability of the matrix and as sintering aids. The mixture was milled and molded by: 1) CIP and 2) Slip-casting. Samples were heated at 1500, 1600 and 1700ºC for 2h without pressure under atmospheric conditions in bed-powders of Si3N4. Samples were characterized by XRD and density, hardness, toughness, bending strength were measured. The structure of the material was observed in SEM/EPMA to verify the distribution of the materials in the composite and the contact between filler surface and the matrix. The formation of SiON2 was observed in the sintered material due to reaction between both nitride and carbide in the Y-TZP matrix, since SiC and Si3N4 were heated in the same conditions and they didn’t exhibit any reaction with the O2 present in the same bed-powder. Furthermore the material showed an increment of both hardness and toughness as temperature increases. The samples presented considerable resistance of oxidation below 1100ºC. In fact, it was verified that the formation of Si2N2O can show some advantages like mechanical modulus improvement. Key-words : Zirconia, Composite, Nitride, Carbide, Oxynitride
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