Layer growth of the hafnium nitride phase, ζ-Hf4N3-x, was studied as a function of time and temperature by nitriding Hf metal sheets. The chemical N diffusion was described by:

D(cm2/s) = 0.39 exp[-2.73(eV)/kT]

W.Lengauer, D.Rafaja, P.Ettmayer: Materials Science Forum, 1994, 155, 549-52