Fast X-ray diffraction crystal size distribution analysis

by Sigmund Heinrich Neher
Cumulative thesis
Date of Examination:2018-07-03
Date of issue:2018-09-11
Advisor:Prof. Dr. Werner F. Kuhs
Referee:Prof. Dr. Werner F. Kuhs
Referee:PD Dr. Helmut Klein
Referee:Prof. Dr. Sharon Webb
Referee:Dr. Heidrun PD. Sowa
Referee:Dr. Burkhard Schmidt
Referee:Dr. Volker Karius
Persistent Address: http://dx.doi.org/10.53846/goediss-7050

 

 

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Abstract

English

Fast X-ray Diffraction Crystal Size Distribution analysis (FXD-CSD) constitutes a novel method to determine volume-based crystal size distributions (CSD) of crystalline powders or polycrystalline materials in the lower µm range. The method uses the diffracted integrated intensity of thousands individual crystals to determine the crystal volumes of the sample via a reference-based scaling procedure. The scaling is possible through a reference sample X-ray measurement with known CSD. For the sample and the reference sample measurement, a two-dimensional detector and a goniometer with at least one rotation axis is mandatory. The integrated intensities are obtained via step-wise rotation measurements. This way several hundred frames are collected for each sample. The collected data is analyzed by a specially developed software package, written in Python. The thesis comprises three peer-reviewed research papers, all having FXD-CSD as applied core method. The first manuscript (Chapter 2) describes the method and its functionality as well as its application range and limitations. Chapter 3 is demonstrating the application of the method, having technical ceramics as samples under investigations. In Chapter 4, FXD-CSD is used to answer fundament research questions, concerning crystal coarsening in gas hydrates. Chapter 1 provides an introduction to all necessary topics needed to understand the procedure of FXD-CSD and gives an overview over the previous work carried out in our group. The thesis closes with a general conclusion and an outlook regarding future applications and further improvements
Keywords: crystal size distribution; FXDCSD; method; polycrystaline materials; CSD
 
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