The effect of dissolved Pd upon H absorption and mobility was studied by using cathodic polarization and H permeation techniques in 1N NaOH. It was found that the addition of Pd led to a higher H permeation rate. This was due to an increased diffusivity (table 54) and a decreased H-trapping effect. No marked differences were noted, in the polarization parameters, due to the Pd additions. The results suggested that Pd segregated to potential H traps, such as Mn inclusions, and then repelled H. This rendered potential traps harmless.

F.Fondeur, T.A.Mozhl, B.E.Wilde: Corrosion Science, 1988, 28[5], 461-70

Table 54

Effect of Pd upon H Diffusion in AISI 4130