2002 Volume 35, p155-162
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<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>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<jats:sub>6</jats:sub>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: (<jats:italic>a</jats:italic>) sintering initially relieves residual strain present in the MgO powder used to sinter the ceramics and also promotes grain growth; (<jats:italic>b</jats:italic>) 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 (<jats:italic>c</jats:italic>) introduction of the second phase (Y<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>) 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.
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