THE ROLE OF MW PLASMA TREATMENT ON THE CORROSION RESISTANCE OF STAINLESS STEELS

Two stainless steels (S32404 duplex and S32615 austenitic) were subject to the carbon/nitrogen plasma treatment to examine the role of alloy composition and structure in the behavior of surface during modification. The modification process was performed in the electron cyclotron resonance (ECR) micro wave plasma system, with the frequency of 2.45 GHz and the generator power of 350 W, and with the use of reactive gas mixtures containing CH4 and N-2, at the low temperature of 400 degrees C and under pressure of 0.2Tr. The treated surface was analyzed by means of X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the samples was determined on the basis of LSV polarization curves in 3% sodium chloride solution at 37 degrees C. The treated steel surfaces showed a higher tendency for passivation and higher pitting corrosion resistance compared to the non-modified surfaces.