Study of the effects of plasma immersion ion implantation on austenitic stainless steel using E × B fields

• In E × B field, the intense ion bombardment leads to temperature elevation of the sample.
• Nitrogen implantation in E × B leads to a high implanted dose in a shorter treatment time.
• PIII in E × B improves the mechanical and tribological properties of the samples.

The effect of magnetic field enhanced plasma immersion ion implantation (PIII) on SS304 austenitic stainless steel samples has been investigated. Application of magnetic field in PIII process leads to the formation of the crossed E × B field configuration, promoting the increase of the plasma density by electron-neutrals collision. As a result, a high nitrogen ion flux on SS304 sample was achieved. In this experiment, a moderate temperature of about 350 °C was measured after two hour of treatment, discarding the possibility of the formation of chromium nitride. Measurements performed by Auger electron spectroscopy (AES) showed the formation of a nitrogen implanted layer which was much greater than the one obtained by standard PIII (at the same pulsing conditions). Due to that, new peaks in the characteristic profile of X-ray diffraction were observed as consequence of the formation of a new phase (γN phase). It has caused as twice as high improvement in the surface hardness compared to the conventional PIII. Consequently, a substantial reduction in the wear rate was obtained.