Enhanced thermal shock and oxidation resistance of Si2BC3N ceramics through MWCNTs incorporation

摘要

Multi-walled carbon nanotubes （MWCNTs） reinforced Si2BC3N ceramics were preparedthrough mechanical alloying （MA） and following spark plasma sintering （SPS）. The thermal shockresistance of Si2BC3N ceramics was evaluated comparatively through ice water quenching test andtheoretical prediction. Furthermore, the oxidation resistance of MWCNTs incorporated Si2BC3Nceramics was evaluated under high temperature. The results show that the calculated parameters suchas the critical thermal shock temperature （R） and the thermal stresses resistance （Rst）, as well as thetoughness （R′′′′） are improved with addition of 1 vol% MWCNTs. In addition, the crack propagationresistance of 1 vol% MWCNTs incorporated Si2BC3N ceramics is obviously improved throughgenerating more tortuous crack propagation paths attributing to the ＂crack bridging＂, ＂pull-out＂, and＂crack deflection＂ mechanisms of MWCNTs. Therefore, the residual strengths of 1 vol% MWCNTscontaining specimens remained the highest after the thermal shock tests. Besides, the present workalso reveals that the oxidation resistance is more sensitive to relative density than MWCNTs addition.