Microstructural analysis of nickel hydroxide: Anisotropic size versus stacking faults

Abstract

Two different approaches for studying sample's contributions to diffraction-line broadening are analyzed by applying them to several nickel hydroxide samples. Both are based in the refinement of powder diffraction data but differ in the microstructural model used. The first one consists in the refinement of the powder diffraction pattern using the FAULTS program, a modification of DIFFaX, which assigns peak broadening mainly to the presence of stacking faults and treats finite size effects by convolution with a Voigt function. The second method makes use of the program FULLPROF, which allows the use of linear combinations of spherical harmonics to model peak broadening coming from anisotropic size effects. The complementary use of transmission electron microscopy has allowed us to evaluate the best approach for the Ni(OH)2 case. In addition, peak shifts, corresponding to reflections 10l (l0) were observed in defective nickel hydroxide samples that can be directly correlated with the degree of faulting.