Characteristic of the nitride layers on the stainless steel at low temperature

The particular properties of stainless steel nitrided at low temperature (high corrosion and wear resistance) make it a very interesting scientific problem. It was stated that the new phase ‘expanded austenite’, which is formed during low temperature ion nitriding is responsible for this increase of the steel properties. But the conditions of the ‘expanded austenite’ formation as far as its structure are still unknown. In the present paper, the author presents her investigation on nitrided layers obtained on austenitic stainless steels. Samples were gas nitrided with the activating pre-treatment—cathode sputtering in nitrogen. The temperatures of the gas treatment were 723 and 773 K. It was stated, that depending on the sputtering parameters and temperature of the gas treatment, the nitride layers with various structure were formed. Moreover, the state of the surface before nitriding had influence on the nitrided layer formation.