A capillary method was used to determine H mobility in molten alloys, and the concentration dependence of the diffusion coefficients was determined. A slight positive deviation from ideal solution behavior was observed for Ni-Fe alloys, and was caused by Fe2+. The Co, which ionized to Co2+ (and partially to Co3+), decreased the strength of H bonds to the matrix and thus increased the H mobility. The data (table 122) were used to derive a generalized equation for H diffusion in multi-component Ni-alloys.

A.B.Shalkevich, B.V.Linchevskii: Izv. Akad. Nauk SSSR, Met., 1975, 4, 67-9

Table 122

Diffusivity of H in Molten Ni-Fe-Co and Ni-Co-Cr at 1600C