A study was made of the diffusion of 32P in single crystals of α-phase material at 700 to 850C. The results could be described by:

D (cm2/s) = 1.55 x 10-1 exp[-138.2(kJ/mol)/RT]

perpendicular to the c-axis, and by:

D (cm2/s) = 4.70 x 100 exp[-172.3(kJ/mol)/RT]

parallel to the c-axis.

H.Nakajima, J.Nakazawa, Y.Minonishi, M.Koiwa: Philosophical Magazine A, 1986, 53[3], 427-37