Effect of Promoters on the Permeation of electrolytic hydrogen through steel

Measurements of the permeation rate of electrolytic hydrogen through steel membranes have shown that compounds of P, As, Sb, S, Se, and Te enhance the entry of hydrogen into the steel only under conditions resulting in the formation of hydrides of hydrides of these elements. It may be presumed that the hydrides which are dissociatively chemisorbed on the cathode are able to assit in the transmission of hydrogen atoms across the electrolyte metal interface, while adsorbed hydroxylions, may be presumed to interfere with the action of hydrides and thus to inhibit permeation.