Self-diffusion was analyzed in non-stoichiometric intermetallic compounds with B2 or L12 structures. It was shown that thermal and compositional antistructure defects appreciably affected the diffusivity, and formed so-called anti-structure bridges for vacancy migration; without additional disordering of the intermetallic compound. This contribution was found to have a percolative nature for both sub-lattices, in the case of the B2 structure, but percolation had to be taken into account only for diffusion of the minor element in AB3 intermetallic compounds having the L12 structure. Numerical calculations were carried out for the CoGa triple-defect intermetallic compound. The threshold anti-structure defect concentrations were equal to 0.049 for B2 structures and 0.0347 for the a sub-lattice of an AB3 compound having the L12 structure. Due to the temperature dependence of the defect concentration, the percolation threshold was also temperature-dependent.

Diffusion by Anti-Structure Defects in Non-Stoichiometric Intermetallic Compounds with B2 and L12 Structures S.V.Divinski, L.N.Larikov: Journal of Physics - Condensed Matter, 1997, 9[37], 7873-83