Improving corrosion resistance of CrTiAlN coating by post-deposition treatments

In this paper, post-deposition treatments such as thermal oxidation and polymethyl methacrylate sealing were applied to CrTiAlN coated samples to alleviate the detrimental effects of coating defects on the performance against corrosion. As-deposited and post-deposition treated coating specimens were subjected to electrochemical measurements in 3.5% NaCl aqueous solution. Electrochemical impedance technique was used to assess coating degradation as a function of immersion time. The testing results indicate that the post-deposition treatments can markedly improve corrosion resistance of the coating with no obvious degradation being observed for the treated samples during a long term exposure to the saline solution.