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Quantitative Analysis of High‐Alumina Refractories Using X‐ray Powder Diffraction Data and the Rietveld Method

1991; Wiley; Volume: 74; Issue: 3 Linguagem: Inglês

10.1111/j.1151-2916.1991.tb04069.x

1551-2916

Ian C. Madsen, Russell J. Finney, R. C. Flann, M. T. Frost, Bill Wilson,

Advanced ceramic materials synthesis

Quantitative determination of phase abundance in high‐alumina refractories has been performed using the Rietveld refinement method applied to X‐ray powder diffraction data. The use of a “whole‐pattern” method for analysis has allowed the simultaneous determination of accurate unitcell parameters and the phase abundance of major (mullite and cristobalite) and minor (quartz, corundum, and andalusite) phases. A comparison of the accurate unit‐cell parameters, produced during refinement, with published data has allowed the composition of mullite to be estimated at 3:2 Al 2 O 3 :SiO 2 . Cristobalite has been shown to be present in two distinct forms, both of which have been quantified in spite of severe overlap in their diffraction patterns. There is excellent agreement between SiO 2 and Al 2 O 3 contents calculated from the measured phase contents and those measured by X‐ray fluorescence spectrometry. The addition of fluorite in a known amount as an internal standard has allowed the estimation of the amount of amorphous material present.