Evaluation via multivariate techniques of scale factor variability in the rietveld method applied to quantitative phase analysis with X ray powder diffraction

Materials Research

Terezinha Ferreira De Oliveira²  Roberto Ribeiro De Avillez¹  Eugenio Kahn Epprecht¹  Joaquim Carlos Barbosa Queiroz² 

[1] ,Universidade Federal do Pará Departamento de Estatística Belém PA ,Brazil

关键词: Quantitative Phase Analysis;    Rietveld method;    experiment design;    multivariate statistical analysis;   

DOI  :  10.1590/S1516-14392006000400005

来源: SciELO

【 摘 要 】

The present work uses multivariate statistical analysis as a form of establishing the main sources of error in the Quantitative Phase Analysis (QPA) using the Rietveld method. The quantitative determination of crystalline phases using x ray powder diffraction is a complex measurement process whose results are influenced by several factors. Ternary mixtures of Al2O3, MgO and NiO were prepared under controlled conditions and the diffractions were obtained using the Bragg-Brentano geometric arrangement. It was possible to establish four sources of critical variations: the experimental absorption and the scale factor of NiO, which is the phase with the greatest linear absorption coefficient of the ternary mixture; the instrumental characteristics represented by mechanical errors of the goniometer and sample displacement; the other two phases (Al2O3 and MgO); and the temperature and relative humidity of the air in the laboratory. The error sources excessively impair the QPA with the Rietveld method. Therefore it becomes necessary to control them during the measurement procedure.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License