A general formula for the simultaneous gas-driven and plasma-driven permeation of T was developed by analogy to an electrical circuit. A permeation potential and resistance were defined for diffusion in the bulk and recombination at the surface. The gradient of permeation potential versus permeation resistance was considered to be the general driving force for permeation through a laminate. The formula was used to calculate the permeation flux of H through AISI 316 stainless steel.

W.M.Shu, K.Watanabe: Physical Review B, 1997, 55[15], 9348-51