Rev.Adv.Mater.Sci. (RAMS)
No 8, Vol. 18, 2008, pages 764-768

RIETVELD-BASED QUANTITATIVE ANALYSIS OF MULTIPHASE POWDERS WITH
NANOCRYSTALLINE NiAl AND FeAl PHASES

Grzegorz Dercz, Dariusz Oleszak, Krystian Prusik and Lucjan Pająk

Abstract

The influence of crystallite size on the quality of Rietveld refinement and on the accuracy of quantitative phase determination by Hill-Howard procedure based on Rietveld analysis was tested. The studies were performed on two four-phase powder samples. The content of phases in both powders was the same and equal to 62.5, 12.5, 12.5, and 12.5 wt.% for NiAl, FeAl, Al2O3 and TiC, respectively. The crystallite sizes of all phases are above 100 nm, except for aluminides in sample B for which they are of nanoscale. The crystallite sizes were analyzed by using Williamson-Hall method. The accuracy in content determination of Al2O3 and TiC phases was practically the same for both samples and was equal to 4% for Al2O3 and 6% for TiC. The presence of nanosize aluminides in the sample worsened this accuracy from 2% to 4% for NiAl and from 2% to 10% for FeAl. The powder morphology was analyzed by SEM method.

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