Nitrogen ion implantation into pure iron for formation of surface nitride layer

摘要

Low energy N ion implantation into pure Fe was performed to study Fe1-xNx formation under various ion irradiation conditions. It was shown that after the room-temperature implantation the amount of N introduction reaches a saturation at about 42% atomic density. Increasing N fluences further does not increase N levels. For the N saturated layer, adding post-irradiation annealing causes N out-diffusion at 300 degrees C and higher temperatures. On the other hand, N implantation at elevated temperatures does not provide extra thermal stability. Transmission electron microscopy and localized diffraction analysis show that the metastable N saturated layer contains a mixture of Fe3N and FeN2.