Procedure of the Quantitative Powder X-Ray Diffraction Analysis of Low-Temperature Alumina Forms

Abstract

A procedure is proposed for the quantitative powder X-ray diffraction (XRD) analysis of powder mixtures of nanocrystalline low-temperature alumina forms. It is based on the presentation of the XRD pattern of the mixture being analyzed by a linear combination of the XRD profiles of reference oxides. The purpose of the quantitative analysis is the least-squares refinement of weight coefficients of the profiles until agreement is achieved between the experimental and generated XRD patterns. The pre-normalization procedure of the experimental XRD profiles with conversion to electronic units enables the analysis of data obtained on instruments with different measurement geometries and instrumental parameters. The procedure is verified using γ-Al₂O₃ and χ-Al₂O₃ mixtures of set compositions, and the accuracy of this procedure is compared with that of the calibration plot method. The absolute error of the χ-Al₂O₃ weight fraction determined by the procedure proposed is two times lower than that of the calibration plot method: 5 wt.% against 10 wt.%. By simulating the noise in the model XRD profiles it is shown that the random error contribution is about 1 wt.%.