Dependence of nitrogen implantation by the PIII process at low energy on pressure and temperature

A study is reported of the influence of both temperature and nitrogen gas pressure on the microhardness and corrosion resistance of AISI 304 stainless steel, PIII treated in a DC plasma discharge in a toroidal chamber. The sample temperatures were stabilised at various gas pressures within the range 1×10−3 to 2×10−1 mbar by adjusting the pulse duration (50-75 μs) while maintaining constant the bias voltage (−5 kV) and pulse frequency 1 kHz. It was found that treatment below ∼520 °C substantially enhances the microhardness as well as the corrosion resistance of the samples. The experiments also showed that treating the samples at temperatures above ∼520 °C adversely modifies the properties associated with corrosion resistance.