Hydrogenation of Mg thin films in CH4 + Ar plasmas

Magnesium films were magnetron sputter deposited on AISI 316L stainless steel and hydrogenated at 450 K by the plasma immersion ion implantation technique using CH4 + Ar gases under a pressure of 10 Pa. The goal was to obtain hydrogen separation and formation of hydrides in Mg film thus avoiding a hydrogen gas purification process. The depth profiles of C and H atoms across the Mg film were analyzed by the Nuclear Reaction Analysis and secondary ion mass spectrometry. After 0.5 h of plasma treatment with a 1 kV bias voltage, C atoms remained in the near surface region while H atoms were homogeneously distributed across the entire film thickness. The results are explained on the basis of C and H ion implantation and atomic transport kinetics along the grain boundaries of a nanocrystalline Mg film.