Anomalous oxidation behaviour of pressureless liquid-phase-sintered SiC

Publication year: 2011
Source: Journal of the European Ceramic Society, In Press, Corrected Proof, Available online 14 June 2011

F., Rodríguez-Rojas , A.L., Ortiz , F., Guiberteau , M., Nygren

The oxidation behaviour of pressureless liquid-phase-sintered (PLPS) SiC, an important non-oxide engineering ceramic, was investigated, and was found to be universally anomalous. Thermogravimetry oxidation tests performed in oxygen in the temperature range 1000–1225°C on three PLPS SiC ceramics fabricated with different combinations of Al2O3–RE2O3 (RE=Gd, Sc, or Sm) as sintering aids indicated that the oxidation is in all cases passive and protective, but unexpectedly anomalous in the sense that the oxidation resistance does not scale inversely with temperature. In particular, in all cases it was observed that there is less oxidation above 1100°C than below, in clear contradiction to the…