engleski

Quantitative phase analysis using the matrix-flushing principle and powder pattern fitting

A new method for quantitative phase analysis of a multicomponent powder is proposed. The method is based on the matrix-flushing principle [F. H. Chung, J. Appl. Cryst. 7 (1974) 519-525]. It involves the preparation of (a) a mixture of examined multicomponent system and corundum at the one-to-one weight ratio, and (b) a mixture of the pure component, the weight fraction of which is to be determined - say X, and corundum at the one-to-one weight ratio. Two approaches of X-ray diffraction analysis can be performed. In the first one the intensities of the strongest diffraction line of the component X and of corundum are to be measured for both mixtures (a) and (b). The weight fraction of the component X is related to the ratios of integrated intensities of the strongest lines of that component and corundum for the mixtures (a) and (b). Alternatively, the whole XRD patterns of the mixtures (a) and (b) are to be recorded and decomposed into individual lines. The weight fraction of the component X is then related to the ratios of the sum of all diffracted intensities for the component X and the sum of all diffracted intensities for corundum in both mixtures, (a) and (b) respectively. The method was tested on two ternary mixtures, ZnO + CaCO3 + a-SiO2 and a-SiO2 + CaCO3 + soot. Decomposition of XRD patterns was done using the fitting programs PROFIT and WPPF [H. Toraya, J. Appl. Cryst. 19 (1986) 440-447]. For quick result the first analysis approach gives the satisfactory accuracy, but for more accurate result the latter one is better.

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