Abstract Hydrogen permeation experiments were carried out with different thickness of Ni membranes; 20, 50 and 200 μm, pre-conditioned for the same surface conditions. Hydrogen plasma was created by ECR heating and plasma driven permeation (PDP) through the Ni membrane of 523 K was investigated. With gas driven permeation (GDP) experimental data, recombination coefficients of the upstream and the downstream surfaces (m4 s−1) were calculated; 1.6×10−29≤Kl, 7.9×10−30