Hot corrosion and cyclic oxidation effect on deep cryogenically treated nimonic-90 superalloy

In a variety of high temperature engineering applications including aerospace, marine, power plants etc. Nimonic-90 because of its ability to withstand high temperatures, Nimonic-90 is a preferred engineering material in various high-temperature applications, such as aerospace, marine, and power plants, due to its exceptional ability to withstand elevated temperatures. In such a high-temperature application, Nimonic-90 experiences oxidation and hot corrosion after a period of time. It has been observed that Deep Cryogenic treatment (DCT) appreciably improved the mechanical properties of the materials but its effect on hot corrosion and oxidation at high temperatures has still not been thoroughly investigated. Therefore, this study investigates the effect of Deep Cryogenic Treatment on hot corrosion and oxidation of Nimonic-90 superalloy at 9000C. The samples were subjected to Deep Cryogenic Treatment cycle at −1960C and then oxidation and hot corrosion environment was provided in a thermal cyclic furnace. At 900°C, new phases, such as oxides of nickel, chromium, and titanium, formed. These phases acted as protective layers, improving Nimonic-90′s corrosion resistance and preventing further oxidation. Deep Cryogenic Treatment has shown significant improvement in corrosion behaviour of Nimonic-90 superalloy. The findings demonstrated that the weight gain resulted from hot corrosion products was greater than the weight gain in an oxidation environment. The most corrosion-resistant sample in hot corrosion had an average scale thickness of 70.97 µm which was 31.96% smaller xthan the untreated sample whereas in oxidation samples, the most corrosion resistant sample had average scale thickness of 23.97 µm which was 52.06% smaller than the oxidized untreated sample.