Homogeneity range and crystal structure of the Ca2Mg5Zn13 compound

The homogeneity range and crystal structure of the Ca2Mg5Zn13 ternary solid solution were determined using SEM, EPMA, EBSD, TEM and X-ray diffraction. This compound has the CaxMgyZnz (8.2 <= x <= 9.1; 27.1 <= y <= 31.0; 60.8 <= z <= 64.7) composition range at 335 degrees C. The refinement of the XRD patterns was carried out by Rietveld analysis. XRD data showed that this solid solution crystallizes in a hexagonal structure having P6(3)/mmc (194) space group and Sm3Mg13Zn30 prototype. The well indexed SAED patterns and Kikuchi diffraction pattern obtained from TEM and EBSD confirmed the crystallographic information obtained by XRD. The atomic coordination spheres and site occupancy were determined. On the basis of the atomic occupancy results and the crystallographic details, a three-sublattice model is proposed for this compound. (C) 2012 Elsevier B. V. All rights reserved.