Departmental Bulletin Paper <技術報告> Implementation of the Williamson-Hall and Halder-Wagner Methods into RIETAN-FP

Izumi, Fujio  ,  Ikeda, Takuji

Microstructural evaluation is important to understand physical and chemical properties of polycrystalline materials, particularly in the field of nanotechnology. The latest version of a multi-purpose pattern-fitting system, RIETAN-FP, offers new features of Williamson–Hall (WH) and Halder–Wagner (HW) methods to determine crystallite sizes and microstrains from integral breadths, β, evaluated after the Rietveld or Le Bail analysis of X-ray and neutron powder diffraction data. Contributions of instrumental broadening are subtracted with analytical results of instrumental standards showing negligible sample broadening. Gnuplot is used for the graphical representation of linear relationships: βcosθ vs. sinθ in the WH plot and (β/tanθ)2 vs. β/(tanθ sinθ) in the HW one. Deviations from the linear relationships can easily be recognized by the resulting graphs. With these two methods, the mean volume-weighted size,〈D〉v, of microcrystalline CeO2 was determined at 29.96 nm (WH) and 28.92 nm (HW), which are in good agreement with values reported for the round-robin sample. The present new features concerning microstructural characterization must deliver added value to users of RIETAN-FP in both academic institutions and industries.

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