Evaluation of Wear, Oxidation and Corrosion Behaviors of Nickel-Based Superalloy Coatings Fabricated by GTAW Method

In this study, three nickel-based superalloys consist of Colmonoy 6 ،Inconel 625 and Hastelloy C276 was coated by GTAW process method on 310 stainless steel. Evaluation of hardness, wear behavior and wear mechanism of samples was performed with Vickers, pin-on-disc method and using SEM images, respectively. The high temperature oxidation behavior was also studied at 1050°C in 8 cycles of 24hours. Also, to investigate corrosion behavior of samples, potentiodynamic polarization test was used in a solution of sulfuric acid and sodium chloride. The surface hardness results showed higher hardness of the Hastelloy C276 (727 HV) and Colmonoy 6 (612 HV) than the Inconel 625 (338 HV) and the steel substrate (217 HV). The best wear behavior was related to Hastelloy C276 with friction coefficient of 0.28. Surface morphology studies of the samples show a change in the wear-resistance mechanism from sliding to adhesive by applying nickel-base coatings on 310 stainless steel. In high temperature oxidation test, minimum weight gain was calculated for Hastelloy C276 (0.5mg/cm2). Corrosion test shows that fabrication of coatings improved 310 stainless steel corrosion resistance which maximum corrosion potential (-119/9 mV) and minimum corrosion current density (0.14 µA.cm-2) was owned by Hastelloy C276. Finally with considering the results, it seems that Hastelloy C276 be as the most desirable option with the aim of coating on 310 stainless steel in high-temperature conditions.