The tracer grain-boundary diffusion of 63Ni, in slightly hypostoichiometric alloys which contained a few percent of Cr, Fe or Zr, was studied by using serial sectioning and residual activity methods. Measurements of grain-boundary diffusivity were carried out temperatures of 873 to 1273K. It was found that the addition of Cr, Fe and Zr decreased the diffusivity, and increased the activation enthalpy of 63Ni.

Grain-Boundary Diffusion of Nickel in Cr-, Fe- and Zr-Modified Ni3Al Intermetallic. J.Cermak, J.Ruzickova, A.Pokorna: Intermetallics, 1999, 7[6], 725-30