The diffusivity was measured by using the electrochemical permeation method at temperatures of between 283 and 313K. It was found that the diffusivity was lowered by alloying with 0.46 to 5.17at%Al, 0.53 to 5.06at%Si, 0.47 to 7.67at%V, 0.4 to 5.1at%Cr, 0.35at%Mn, 0.41 to 4.79at%Co, 0.98 to 5.16at%Ni, or 0.51 to 3.35at%Mo (figures 5 and 6). This was attributed to the effect of H interstitial sites, around the substitutional atoms, which acted as trapping sites. It was concluded that the diffusion behavior of H in the alloys was markedly affected by elastic interactions between H and the alloying atoms.

Effect of Substitutional Alloying Elements (Al, Si, V, Cr, Mn, Co, Ni, Mo) on the Diffusion Coefficient of Hydrogen in α-Iron. H.Hagi: Journal of the Japan Institute of Metals, 1991, 55[12], 1283-90

Figure 7

Effect of Alloying Additions upon the

Diffusivity of H in Fe at 298K