Abstract

Mullite, Al2[Al2+2xSi2-2x]O10-x(0.17≦x≦0.59), is a non-stoichiometric compound in Al2O3-SiO2 system, represents a series of alumina silicate minerals without certain chemical compositions, which also cause the different X-ray diffraction patterns of mullite. Therefore, 5 different mullite references were given in the databank of commercial software of Siroquant for quantitative phase composition analysis of materials. When performing quantitative phase composition analysis of sintered mullite, the test results of mullite contents are always different from each other if a mullite reference or combination of them was selected. With the addition of spike phase, such as ZnO, the glass contents determined by siroquant were also present big divatation by inputing the weighted content of spike phase initially. This may indicates difference between the used reference mullite structure and actual mullite structure of sample affect the analysis results significantly. With the aim to improve the accuracy of phase composition analysis results of sintered mullite by Siroquant software, ZnO was added as a reference material, and the minimum relative standard deviation (MRSD) method based on least squares criterion principle was used to determine the analysis results. Data statistics and results analysis show that the most possible mullite structure of samples could be determined by using the MRSD method, and meanwhile, this method can also improve the accurcy of measured glass content to that of chemical method.