The entry and transport of H in P-, S- or (P+S)-implanted specimens with a fluence range of 1015 to 1017/cm2 were investigated using an electrochemical permeation technique and etching treatment (0.2%HF solution). From the H permeation transients obtained, the effective H concentration (CH), apparent H diffusion coefficient (Dlag) and breakthrough time (tlag) were estimated by using the time lag method in addition to the steady state permeation current density (P∞). It was found that at a fluence of less than 1016/cm2 almost all H permeation transients of the implanted Ni specimens were affected by the defects (vacancy, compressive stress and so on) generated during ion implantation process. At a high fluence of 1017/cm2 the H permeation transient had a specific behavior because of the formation of amorphous phase for P, the structure changed from face-centered cubic structure to body-centered cubic structure for S and both of them for the mixture (P and S). However, a synergistic effect of P and S was not observed on the H permeation transient. The behavior of these parameters, depending upon fluence and implanted element, was explained in terms of the number of H-entry sites, the number of defects, the properties of the amorphous phase and the structure.

Hydrogen Permeation Behavior in Pure Nickel Implanted with Phosphorus, Sulphur and their Mixture. R.Nishimura, H.Inoue, K.Okitsu, R.M.Latanision, G.K.Hubler: Corrosion Science, 2007, 49[3], 1478-95