Effect of pack cementation on oxidation behavior of Inconel 617

Abstract

The effects of aluminized coating on Inconel 617 prepared by pack cementation method were analyzed by optical microscope. A pack aluminizing process at 900°C for 1 h has been employed on the nickel-base superalloy Inconel 617. A structure is observed on the surface of the aluminide coating. A finger-like interdiffusion zone is found between the aluminide layer and the substrate. Fine precipitates with complex phases are distributed in the NiAl layer. The oxidation tests of aluminized alloys and untreated substrates were conducted at 950°C for 480 h. It was observed that the aluminizing process greatly enhances the oxidation resistance of Inconel 617 at 950°C due to a dense and protective alumina layer formed on the surface. Complex phase transformation reactions occurred in the aluminide layer. Owing to the oxidation and interdiffusion reactions at high temperature. The effects of NiAl on the scale morphology, oxidation behaviour and scale spallation tendency are discussed based on the experimental results, using X-ray diffraction (XRD), scanning electron microscopy (SEM), Vicker`s Hardness (Hv).