Homogeneity Range and Order-Disorder Transitions in R1-xNi2 Laves Phase Compounds

The range of homogeneity has been studied in R1-xNi2 Laves phases (R=Ce, Gd, Tb) by x ray diffraction, microprobe analysis and density measurements. In these compounds the number of R vacancies varies as a function of the nature of the rare earth and the nominal composition. For R=Tb the number of vacancies varies by 0 £ x £ 0.5, from a pure C15 structure to a 2a superstructure accompanied by a cell volume decrease. The order-disorder transition of the rare earth vacancies has been studied under applied pressure for La7Ni16 and versus temperature for all the -xNi2 compounds. The evolution of the pressure and temperature transition, which reflects the binding energy of the vacancies, depends not only on the radius of the R element but also on the mass of the R atom.

PAUL-BONCOUR V.;  LINDBAUM A.;  LATROCHE M.;  HEATHMAN Stephen; 

2006-05-23

Elsevier B.V.

JRC30535

https://publications.jrc.ec.europa.eu/repository/handle/JRC30535,   

10.1016/j.internet.2005.08.003,