Abstract
Liquid-phase-sintered silicon carbide (LPS-SiC) has attracted increasing interest for its superior mechanical properties relative to solid-state-sintered SiC. In contrast to the recent intensive studies on the mechanical properties of LPS-SiC, research on its thermal conduction property is very limited. This study investigated thermal conductivity of LPS-SiC with focus on the effects of various sintering additives. Two sintering additives, a mixture of La2O3 and Y2O3 (LaY) and a mixture of Al2O3 and Y2O3 (AlY), were used for densifying a β-SiC powder. The SiC doped with LaY attained thermal conductivities in excess of 200 W/(m•K); however the SiC doped with AlY had thermal conductivities less than 71 W/(m•K). The difference in thermal conductivity was attributed to the different effects of the sintering additives imposed on lattice oxygen content, concentration of point defects and stacking faults in the sintered SiC ceramics.
