The self-diffusion of 63Ni in monocrystals of the ordered intermetallic compound was investigated. It was found that the activation energies for diffusion perpendicular to, and parallel to, the hexagonal c-axis were almost the same and lay between 2.14 and 2.34eV:

 c-axis:     D(cm2/s) = 63.2 exp[-2.31(eV)/kT]

|| c-axis:     D(cm2/s) = 108 exp[-2.34(eV)/kT]

The Do values were direction-dependent and ranged from 65 to 110cm2/s. The experimental values of the D/D ratio were between 0.87 and 0.79; depending upon temperature.

H.Schmidt, G.Frohberg, H.Wever: Acta Metallurgica et Materialia, 1992, 40[11], 3105-11