Nitriding of austenitic stainless steel by pulsed low energy ion implantation

Low energy ion implantation (LEII) of nitrogen into austenitic stainless steel was carried out using an electronic beam switch for a defined regulation of nitrogen ion flux and an additional external radiation heating for assuring a constant process temperature of 460 °C with the aim to investigate the influence of a varying ion energy and ion flux, respective particle flux on nitrogen diffusion, phase formation and hardness of the nitrided austenitic stainless steel, grade 1.4301, samples. No influence of both process parameter variations on the layer thickness was found as long as identical temperature profiles were maintained. This implies that the nitrogen diffusion is decoupled from nitrogen insertion at constant temperature for sufficiently high nitrogen supply. It was found that the pulsed mode does not influence the expended austenite formation, hardness of the nitrided layers as well as their corrosion resistance compared with a continuous LEII-mode at the same ion source plasma parameters.