Journal of Applied Crystallography

Volume 35, Part 2 (April 2002)

short communications

J. Appl. Cryst. (2002). 35, 274-277 [ doi:10.1107/S0021889801021537 ]

Assessment of preferred orientation with neutron powder diffraction data

H. Sitepu

Abstract: Crystallographic texture (or preferred orientation) characterization of uniaxially pressed molybdite (MoO₃) and calcite (CaCO₃) powders has been carried out using the BT-1 high-resolution fixed-wavelength 32-detector powder diffractometer at the NIST Center for Neutron Research. Initially, each pattern was analysed assuming a random orientation of the crystallites. Subsequently, the March model and the generalized spherical harmonic description were used independently to extract the texture description directly from a refinement with neutron diffraction data of molybdite and calcite. The results indicate that the generalized spherical harmonic description provided a better Rietveld fit than the March model for the molybdite sample that had been subjected to the highest pressure.

Keywords: preferred orientation correction; texture analysis; March model; orientation distribution function; neutron powder diffraction; generalized spherical harmonic descriptor.