Influence of implanted 150 keV Fe ion and 100 keV Mg ions on hydrogen absorption by Pd/Ti/V/Pd/Ti multilayer films on Ti substrate

Abstract

The effect of implanted 150 keV Fe ion and 100 keV Mg ions on hydrogen (H) absorption by Pd/Ti/V/Pd/Ti multilayer films, prepared on Ti substrate, was investigated using the H profiling analytical technique, energy recoil detection analysis (ERDA). The stability of the multilayer stack system at 550 °C was investigated using Rutherford backscattering spectrometry for the investigation of possible intermixing of layers and X-ray diffraction for crystal structure and any possible new phase formation due to elevated temperatures. SEM was used for surface topography investigation. Ion penetration, distribution, and vacancy distribution inside the system, under investigation, were achieved using the Monte Carlo semi-empirical simulation code, Stopping and Range of Ions in Matter, and found to be 700 and 1055 Å for 150 keV Fe ions and 100 keV Mg ions implantations, respectively. ERDA revealed a maximum H amount of ∼ 4.8 at.% at a depth of ∼ 1.8 µm, with ∼ 2.6 at.% average H content over the probed depth in the non-implanted hydrogenated sample. The average H amount values in the 150 keV Fe ions implanted samples, over a probed depth, were found to be ∼ 1.32, ∼1.19 and ∼ 1.09 at.% in samples implanted up to a fluence of 1 × 1014, 1 × 1015, and 1 × 1016 ions/cm2, respectively, with H content, restricted to the surface and near the surface and constantly decreased into the bulk. The average H amount values, over a probed depth, in the 100 keV Mg ions implanted samples, up to 1 × 1014, 1 × 1015, and 1 × 1016 ions/cm2 fluence, were found to be ∼ 1.26, ∼1.25, and ∼ 1.17 at.%, respectively. These results suggest the entrapment of the H atoms by the implanted species and the ineffectiveness of Fe and Mg ion implantation in the enhancement of H absorption and diffusion in these films; at least at the energies and fluence used in this investigation. No indication of intermixing, suggesting that the system was stable up to 500 °C in an H2 environment.