Quantitative phase-composition analysis of liquid-phase-sintered silicon carbide using the Rietveld method

Accurate quantitative X-ray diffraction analysis of SiC-based ceramics is d ifficult because of the significant overlap of the Bragg reflections from t he different SIC polytypes. In this regard, the Rietveld method is a powerf ul tool for the accurate and precise analysis of the phase/polytype composi tions in these materials. In this study, we have used tno different types o f Rietveld codes for the quantitative phase/polytype analysis of a liquid-p hase-sintered SiC specimen: FULPROF, which is based on the classical Rietve ld approach, and BGMN, which is based on the new fundamental parameter appr oach. In both cases, the effect of texture corrections on the precision of the analysis also was studied. The accuracy of the analysis, in terms of th e weight percentage of SIC (all polytypes) and yttrium aluminum garnet liqu id phase, as determined from the starting powder composition, is within the standard deviation of the analysis in both cases (FULLPROF and BGMN), with and without the texture corrections. In addition, in the case of the class ical code (FULLPROF), inclusion of the texture corrections has been shown t o improve the precision. In contrast, the precision of the analysis using t he BGMN code without the texture corrections is better. son-ever, inclusion of the texture corrections is expected to improve the accuracy of the anal ysis.