Evaluation via multivariate techniques of scale factor variability in the rietveld method applied to quantitative phase analysis with X ray powder diffraction
AUTOR(ES)
Oliveira, Terezinha Ferreira de, Avillez, Roberto Ribeiro de, Epprecht, Eugenio Kahn, Queiroz, Joaquim Carlos Barbosa
FONTE
Materials Research
DATA DE PUBLICAÇÃO
2006-12
RESUMO
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.
Documentos Relacionados
- ANALYSIS OF THE UNCERTAINTIES OF THE QUANTITATIVE PHASE ANALYSIS BY X-RAY POWDER DIFFRACTION BASED ON THE RIETVELD METHOD
- A difração de raios X com o método de Rietveld aplicada a bauxitas de Porto Trombetas, PA.
- Application of X-ray diffraction and Rietveld method in Portland Cement study
- Crystal structure determination of thymoquinone by high-resolution X-ray powder diffraction
- Estudo do composto supercondutor Hg, Re-1223 por difratometria de raios-X, com a aplicação do método de Rietveld