Membrane bias effects on plasma-driven permeation of hydrogen through niobium membrane

Niobium membrane was immersed in hydrogen plasma in order to study its interaction with hydrogen ions in the energy range from a few eV to 200 eV, controlled by changing the membrane bias. Degradation of plasma driven permeation (PDP) and enhancement of permeation driven by thermal molecules of cold gas (GDP) were observed when bias voltage was applied to the membrane exposed at plasma because of’ sputtering of non-metal impurity layer at upstream surface. Both dissolution of oxygen and increase of membrane temperature lead to decreasing of membrane bias effect due to rise of surface layer recovering rate.