X-RAY POWDER DIFFRACTION ANALYSIS OF LIQUID-PHASE-SINTERED SILICON CARBIDE CERAMICS

摘要

In an attempt to gain a comprehensive understanding of the microstructural evolution in liquid-phase-sintered silicon carbide ceramics, the effect of the starting β- SiC powder has been studied. Pellets of two different β- SiC starting powders were sintered with simultaneous additions of Al_2O_3 and Y_2O_3 at 1950℃ for 1 hour in flowing argon atmosphere. Here we have used X-ray diffraction to obtain the relative abundance of the resulting SiC polytypes after sintering. The significant influence of the defects concentration on the β to α transformation rate has been determined using the Rietveld method.