• Takahashi, Keisuke

Abstract

<jats:p>A method is presented to examine consecutive <jats:italic>in-situ</jats:italic> X-ray diffraction (XRD) diffractograms using exploratory factor analysis. Systematic changes in the diffractograms are described numerically by score values that could be used to correlate diffraction data with other non-stationary sample properties. Phase and structure evolution in a reacting material can be studied by <jats:italic>in-situ</jats:italic> XRD. The consecutively collected data can be considered a time series of datasets. Time series are non-stationary data. Such non-stationary data are often hard to examine fully by conventional evaluation methods including applications of the Rietveld method. Here a method is presented to avoid shortcomings of conventional evaluation methods. The new method helps to identify and describe significant systematic changes in <jats:italic>in-situ</jats:italic> XRD datasets by numerical values. These systematic changes can represent structural changes as well as changes in phase composition. The method can be used to describe the development of the complex processes of compositional and structural changes. The method is demonstrated using the example of a hydrating Portland cement mortar. This hydration process involves at least 11 phases including non-crystalline phases. In the presented example factor analysis of <jats:italic>in-situ</jats:italic> XRD data results in three variables (factors) describing the observed changes numerically.</jats:p>

Topics

• impedance spectroscopy
• x-ray diffraction
• crystalline phase
• cement