Accuracy in Rietveld quantitative phase analysis: a comparative study of strictly monochromatic Mo and Cu radiations.
J Appl Crystallogr
; 49(Pt 3): 722-735, 2016 Jun 01.
Article
em En
| MEDLINE
| ID: mdl-27275132
ABSTRACT
This study reports 78 Rietveld quantitative phase analyses using Cuâ
Kα1, Moâ
Kα1 and synchrotron radiations. Synchrotron powder diffraction has been used to validate the most challenging analyses. From the results for three series with increasing contents of an analyte (an inorganic crystalline phase, an organic crystalline phase and a glass), it is inferred that Rietveld analyses from high-energy Moâ
Kα1 radiation have slightly better accuracies than those obtained from Cuâ
Kα1 radiation. This behaviour has been established from the results of the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. This outcome is explained, in spite of the lower diffraction power for Mo radiation when compared to Cu radiation, as arising because of the larger volume tested with Mo and also because higher energy allows one to record patterns with fewer systematic errors. The limit of detection (LoD) and limit of quantification (LoQ) have also been established for the studied series. For similar recording times, the LoDs in Cu patterns, â¼0.2â
wt%, are slightly lower than those derived from Mo patterns, â¼0.3 wt%. The LoQ for a well crystallized inorganic phase using laboratory powder diffraction was established to be close to 0.10â
wt% in stable fits with good precision. However, the accuracy of these analyses was poor with relative errors near to 100%. Only contents higher than 1.0â
wt% yielded analyses with relative errors lower than 20%.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article