Corrosion Behavior of Cr(Si)N/301 Stainless Steel System

In this paper, the electrochemical behavior of Cr(Si)N coatings deposited on AISI 301 stainless steel (SS) substrate is investigated. Cr(Si)N films with different Si contents were prepared by dual magnetron sputtering. Potentiodynamic polarization measurements were carried out in NaCl 1% solution to evaluate resistance to localized and general corrosion. These measurements were performed on Cr(Si)N coatings deposited on SS and glass substrates, using a customized electrochemical cell, with the purpose to determine the contribution of SS to the electrochemical response of the coating/SS system. The morphology, composition and microstructure of the surface layers were examined by complementary characterization techniques including XRD, ERD, and SEM. It has been shown that the Cr(Si)N coatings improved significantly the pitting resistance of SS with not pits observed up to 1000 mV anodic polarization as compared to bare SS where the pitting potential was 330 mV. Moreover, the polarization curves of the coated SS exhibited passive-transpassive behavior with slight improvement in the corrosion properties as Si content is increased. This response is the result of electrochemical reactions at the Cr(Si)N/electrolyte interface as demonstrated by the polarization measurements on the coating/glass system.