Diffusivity and solubility of hydrogen as a function of composition in Fe-Ni alloys

Sulfide stress cracking of nickel-containing low-alloy steels

“…Yoshino and Minozaki (1986) studied hydrogen permeation in 0.2-wt% C Cr-Mo-Ni-steels exposed to H 2 S-saturated 5-wt% NaCl with and without addition of 0.5-wt% acetic acid at E OC . In both cases, the hydrogen diffusion coefficient decreased with an increase in nickel content in the 0-to 5-wt% range, in accord with results by Beck et al (1971). Wilde et al (1982) also reported a decrease in the hydrogen diffusion coefficient when 1-wt% Ni was added to a UNS G41300 (SAE/AISI 4130) alloy exposed to a H 2 S-saturated 3.5-wt% NaCl solution acidified with 0.5-wt% acetic acid.…”

“…Wilde et al (1982) found that, in H 2 S-saturated 3.5-wt% NaCl acidified with 0.5-wt% acetic acid, Ni, Pd, and Pt accelerated the rate of the hydrogen evolution reaction (HER), as shown by cathodic polarization curves. However, despite the expected increase in hydrogen recombination rates, the steady-state hydrogen flux increased by about 20% when 1.0-wt% of each of those elements was added to the base alloy, in accord with results by Beck et al (1971). Contrary to this finding, Yoshino and Minozaki (1986) found that the surface hydrogen concentration, which is proportional to the steady-state flux, decreased with increasing Ni content in the range of 0-5-wt% for a comparable Cr-Mo-Ni base alloy composition exposed to a similar solution.…”

“…Assuming the heat treatment was such that equilibrium was reached, the alloys likely consisted of α phase for pure iron and Fe-5-wt% Ni, α+γ phases for alloys with Ni content between 10-and 40-wt%, and γ phase for Fe-Ni alloys with % Ni > 60-wt%. For the Fe-5-wt% Ni alloy, the authors found that the D eff was lower than for pure iron (Beck et al, 1971). Further nickel additions caused a step decrease in hydrogen diffusion coefficient, which was interpreted in terms of the dual-phase nature of the alloy.…”

“…In general, Ni additions resulted in a decrease in J ss ·L, which, based on Equation 9 and the low variability in D lat values with microstructure and composition for ferritic steels (Turnbull & Carroll, 1990), should be related to a decrease in C 0 with increased Ni content. Beck, Bockris, Genshaw, and Subramanyan (1971) reported an increase in steady-state hydrogen flux for samples cathodically charged in NaOH when Ni content increased from 0 to 5-wt%. Wilde, Kim, and Turn (1982) systematically studied hydrogen absorption kinetics as a function of noble element additions, including Ni, Cu, Ag, Pd, and Pt, to UNS G41300 (SAE/AISI 4130).…”

“…However, a better understanding regarding the structure and composition of the sulfide film formed as a function of nickel content in LAS is needed to explain why this reversal was not observed in the control sample (Gooch, 1982a,b). Beck et al (1971) studied the effect of nickel on hydrogen diffusion in Fe-Ni alloys with Ni varying from 0-% to 100-wt% and exposed to a cathodic current with no H 2 S additions. Alloys were annealed at a non-specified temperature and then slowly cooled to room temperature.…”