Radio-tracer diffusion measurements of 63Ni were performed in Ni75AlxGe25-x at various temperatures. The tracer diffusivity was found to depend exponentially upon the Ge content. These compounds had ordered L12 structures, in which Ni-atom diffusion proceeded mainly via Ni sub-lattice site jumps. A change in the diffusivity could be attributed to a change in vacancy concentration on the Ni sub-lattice, as well as to a composition dependence of the saddle-point energy of the diffusion jumps.

Tracer Diffusion of 63Ni in Ni3(Al,Ge) Ternary Intermetallic Compound. C.Cserháti, I.A.Szabó, Z.Márton, G.Erdélyi: Intermetallics, 2002, 10[9], 887-92