Ion driven permeation of deuterium through iron coated with silicon oxide film

Ion-driven permeation of deuterium was studied through an iron (0.1 mm thickness) coated with a SiO₂ of about 30 nm thick. A flux ratio of permeation/incident for the Fe sample ranged from 7.6×10^-5 at 373 K to 1.4×10^-3 at 673 K for the incident ion flux of 6.4×10¹⁸ ions m^-2S^-1 at the ion energy of 0.3 keV. The permeation flux through the back coated sample is lowered by a factor of 1 or 2 orders of magnitude than the case of the Fe sample. The activation energy(0.2eV) of the permeation of these two samples are almost same. As for the front coated sample, the different energy and incident ion flux dependences were observed. Investigations of the SiO₂ coating property under deuterium ion implantation by XPS showed that the coating on the front surface could easily sputtered away during the experiments. Thus, the surface after removing of the coating has a special condition that changes the properties of permeation.