Costituzione e proprietà elettrochimiche degli strati superficiali su acciai inossidabili sottoposti a nitrurazione ionica

Ion nitriding of austenitic stainless steels induces formation of hard surface layers which maintain good corrosion resistance in aqueous solutions (especially AISI 316). This result can be obtained by ion nitriding at 500 degree C followed by a shorter treatment at 400 degree C. After heat treatment, the presence of a new phase, epsilon ', with a proposed formula (Fe, Cr, Ni, Mo0//2 N//1// minus //x, was identified. This paper illustrates results on ion nitrided ferritic, austenitic and austeno-ferritic stainless steels and a comparison is made with the corrosion resistance properties of ion nitrided AISI 316.