Oxidation resistance of SiC-AlN-Re2O3 composites (SiC 50%wt-AlN 50%wt) pressureless-sintered with an innovative and cost-effective method is reported, Yttria, Lutetia, Ytterbia and Erbia were tested as sintering-aids in this pressureless-sintered process which does not require the use of the powder bed to protect samples during the heat treatments, Sintered density was always >95%T.D. and microstructure was mainly composed by 2H SiC-AlN solid solution with well-dispersed grain boundary phases. The sintered samples, after oxidation in the temperature range 1200-1200°C over a period of time of 200h, showed a parabolic oxidation behaviour with diffusion of oxygen through the silica-based surface and interfacial reactions silica-alumina and silica-rare-earth oxides as rate-determining steps.
Oxidation Resistance of Pressureless-Sintered SiC-AlN-Re2O 3 Composites Obtained without Powder Bed
Mingazzini, C.;Burgio, F.;Antolini, F.;Magnani, G.
2009-03-01
Abstract
Oxidation resistance of SiC-AlN-Re2O3 composites (SiC 50%wt-AlN 50%wt) pressureless-sintered with an innovative and cost-effective method is reported, Yttria, Lutetia, Ytterbia and Erbia were tested as sintering-aids in this pressureless-sintered process which does not require the use of the powder bed to protect samples during the heat treatments, Sintered density was always >95%T.D. and microstructure was mainly composed by 2H SiC-AlN solid solution with well-dispersed grain boundary phases. The sintered samples, after oxidation in the temperature range 1200-1200°C over a period of time of 200h, showed a parabolic oxidation behaviour with diffusion of oxygen through the silica-based surface and interfacial reactions silica-alumina and silica-rare-earth oxides as rate-determining steps.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
