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A comparative study of single‐line and Rietveld strain–size evaluation procedures using MgO ceramics
Author(s) -
Pratapa Suminar,
O'Connor Brian,
Hunter Brett
Publication year - 2002
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889801020507
Subject(s) - rietveld refinement , materials science , ceramic , sintering , grain size , voigt profile , analytical chemistry (journal) , x ray crystallography , grain growth , mineralogy , diffraction , neutron diffraction , composite material , crystallography , crystal structure , spectral line , optics , chemistry , chromatography , physics , astronomy
Strain–size evaluations from diffraction line broadening for MgO ceramic materials have been compared using single‐line integral‐breadth and Rietveld procedures with the Voigt function. Diffraction data were measured by Bragg–Brentano X‐ray diffractometry (XRD), without incident beam monochromatization, and neutron diffractometry (ND) to encompass near‐surface and bulk effects, respectively. The specimens consisted of sets of MgO ceramics and MgO–Y 2 O 3 ceramic composites sintered over a range of temperatures. An MgO ceramic sintered at 1723 K for 2 h exhibited slightly less XRD broadening than the standard LaB 6 NIST 660 SRM, and was therefore selected to make instrument profile corrections for both XRD and ND data. It was found for both data types that: ( a ) sintering initially relieves residual strain present in the MgO powder used to sinter the ceramics and also promotes grain growth; ( b ) residual strain of the MgO ceramic minimizes as the sintering temperature increases, and then increases with further rise in the sintering temperature, presumably as a result of intragranular interactions associated with grain growth; and ( c ) introduction of the second phase (Y 2 O 3 ) increases strain and inhibits crystal growth. The single‐line and Rietveld methods gave similar strain values from both the XRD and ND data within the limits of experimental error, but there were substantial differences between the single‐line and Rietveld size estimates determined with the XRD and ND data.