A comparative Study of the Oxidation Behavior of Inconel 738 Superalloy and Laser-Cladded NiCrAlY Coating at Temperature of 1200 ˚C

Inconel 738 superalloy is widely used for hot-section components of gas turbines. These hot-section components are exposed to an extremely oxidative environment at high temperatures and consequently their life span is dramatically decreased. Considering this problem, NiCrAlY coatings can be effectively used to protect the hotsection components. In this study, laser cladding process was used to coat a NiCrAlY alloy on the surface of Inconel 738 substrate for the purpose of improving the high-temperature oxidation resistance. In order to compare the oxidation behavior, oxidation tests at temperature of 1200 ˚C were individually conducted on Inconel 738 substrate and freestanding laser-cladded NiCrAlY coating. Laser cladding of NiCrAlY alloy resulted in the formation of hypo-eutectic dendritic γ/β structure. Moreover, the results of oxidation tests showed that the oxidation resistance of the laser-cladded coating was significantly better than that of Inconel 738 substrate and this coating can be an effective choice for protecting the hot-section components made of Inconel 738 superalloy.