Increasing the Corrosion Resistance of Arc-PVD Coatings on ABS

In order to improve the corrosion resistance of polymer (ABS) components, electroplated nickel-chromium coatings and solutions were introduced to increase resistance to corrosion and remove surface micro-defects in chrome cathodic arc coatings during the coating process. Six solutions were examined: micro-etching with argon plasma, ion bombardment, increasing coating thickness, creating chromium nitride and titanium nitride multilayers, creating coatings with gradient bias voltage, and removing chromium layers during the plating process. Combination coatings of Cr-CrN-Cr and Ti-TiN-Cr with multilayer structures were used on electroplated polymer substrates for coating car handles. Surface treatments were applied in the common sublayer-coating interface. The corrosion behavior of the coatings was investigated using the Copper Accelerated Salt Spray (CASS) test method. The results of CASS showed that surface treatment improves the corrosion resistance of coatings by 50-60%. By eliminating droplets and inclusions on the surface using surface treatments and changing the columnar structure of the coating with bias voltage changes prevents the formation and growth of diffusion paths throughout the defects and prevents the formation of corrosion cells. Furthermore, by removing the electroplated chromium layer and applying coatings onto nickel electroplating, corrosion resistance was improved by up to 80%, providing a hopeful solution for improving the corrosion resistance of coated parts.