Bruker Axs Gmbh

Arnt Kern

A method for automatic determination of the quantitative composition of a powder sample, comprises the following steps: (a) predetermining a list of phases; (b) calculating a theoretical diffraction diagram or theoretical energy-dispersive spectrum; (c) fitting the theoretical diffraction diagram or theoretical energy-dispersive spectrum. In step (a), a list is predetermined which is composed of phases that are actually contained in the powder sample and also phases that are possibly not contained in the powder sample, a threshold value for the phase content is predetermined for each phase, and the following further steps are carried out: (d) elimination of all phases, having phase contents which are below the threshold value, from the list in step (a); (e) repeating steps (b), (c) and (d) with the new list until all phase contents are above their predetermined threshold values; and (f) outputting the composition of the powder sample. This method permits automatic exclusion of amorphous or crystalline phases with phase contents below a user-definable threshold value in profile adjustment methods based on Rietveld or Pawley methods.

Method for determining the quantitative composition of a powder sample

An analytical method for determining crystallographic phases of a measuring sample comprises the steps of acquiring a diffraction pattern of the measuring sample and qualitative phase analysis of the measured diffraction pattern, acquiring an element spectrum of the measuring sample and determining concentrations of chemical elements in the measuring sample from the acquired element spectrum, and carrying out a quantitative phase analysis of the measuring sample on the basis of the measured intensities of the acquired diffraction pattern thereby taking into consideration determined element concentrations as a boundary condition, wherein differences between calculated and measured intensities of the diffraction pattern and between calculated and determined element concentrations are simultaneously minimized in an iterative process. The inventive method permits quantitative phase determination with high reliability.

Growing community of inventors

Wörth, Germany

Arnt Kern