It was found that, at 90 to 330C, the H diffusivity in 0.2C-13Cr martensitic stainless steel could be described by:

D (cm2/s) = 2.82 x 10-3 exp[-34.36(kJ/mol)/RT]

The H diffusivity was 2 to 4 orders of magnitude lower than that in α-Fe, and was 2 to 3 orders of magnitude higher than that in austenitic stainless steels.

J.Xu, X.Z.Yuan, X.K.Sun, B.M.Wei: Scripta Metallurgica et Materialia, 1993, 29[7], 925-30