A simple, accurate and effective polymorphic method to determine phase compositions of SiC-based ceramics

Abstract

A new polymorphic method to determine phase compositions of SiC-based ceramics from their X-ray diffraction profiles has been proposed. Basically, this polymorphic method differs from others already proposed in the literature as follows: (1) a set of parameters is introduced to take into account the possible overlap between different groups of peaks and, (2) a square system is used instead of an overdetermined system to determine the phase composition. The accuracy of the method has subsequently been evaluated using a set of standard X-ray diffraction patterns as a benchmark and the corresponding absolute mean and maximum errors were found to be as low as 2.7 and 6.4%, respectively. In addition, it was also found that the method is much more effective than its polymorphic counterparts, as no physically meaningless negative compositions were found in this study. Moreover, the practical application of the method is quite simple and the phase composition can be determined quickly even using a conventional scientific pocket calculator. We have then demonstrated that the use of the proposed method to determine phase compositions of SiC-based ceramics has several important advantages over other polymorphic methods in terms of enhanced simplicity, accuracy and effectiveness. Parallel analyses of a commercially available α-SiC powder and of a liquid-phase-sintered SiC ceramic further reinforced these arguments.