QUANTITATIVE POWDER X-RAY-DIFFRACTOMETRY PHASE-ANALYSIS OF SILICON NITRIC MATERIALS BY A MULTILINE, MEAN-NORMALIZED-INTENSITY METHOD

A general purpose multiline, mean-normalized-intensity (MNI) method, d erived from a procedure proposed in the literature, was applied to pha se-composition analysis of powders containing alpha- and beta-silicon nitride and small amounts of free silicon. Results obtained using peak and integrated intensities to derive the MNI values for the phases we re compared with values determined by Rietveld pattern fitting accordi ng to error assessments based on the MNI standard deviation estimates calculated by assuming that the MNI data for each phase follow Gaussia n statistics, and Rietveld-derived standard deviations. The MNI result s for the integrated intensities agreed reasonably with the Rietveld d eterminations and were discernibly superior to results obtained with p eak intensities. The study demonstrated the power of the MNI method as a general tool for materials analysis.