Development of highly hard and corrosion resistant A286 stainless steel through plasma nitrocarburizing process

After plasma nitrocarburizing, a dual layer was formed consisting of nitrogen and carbon in the top layer followed by carbon in the bottom layer. Compared with the untreated A286 stainless steel specimens, the microhardness values measured from the plasma nitrocarburized specimens treated at 400 and 450 °C increased by a factor of two and three respectively. The electrochemical corrosion behavior of the plasma nitrocarburized A286 specimens has been studied in 3.5 wt.% NaCl solution. The results show that specimens treated at 400 °C for 4 h has better pitting corrosion resistance and higher surface hardness compared with that of the untreated A286 stainless steel. This is mainly attributed to the presence of carbon and nitrogen in the modified layer existing as a solid solution.