Abstract:In order to further improve the oxidation resistance of the open-cell Ni-Cr-Fe alloy foam, the Y-Cr and Ce-Cr coatings were deposited onto the Ni-Cr-Fe alloy foam by a pack cementation process, respectively. The oxidation resistance of Y-Cr and Ce-Cr coatings were also studied under static oxidation conditions for 120 h at 900℃ and 1000℃. The phase composition, the morphology and microstructure of the Y–Cr coating and the Ce–Cr coating before and after oxidation were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results show that the Ce–Cr coating is continuous and compact, and surface grain refinement in Ce–Cr coating can be achieved by comparison of experimental results in Y–Cr coating. The interface between coating and substrate is combined closely. Simultaneously, the Ce–Cr coated foam has better high-temperature oxidation resistance than the Y–Cr coated foams, and the oxidation kinetics curve of Ce-Cr coated foam follows a parabolic law. This is because that a uniform and dense Cr2O3 layer is formed on the surface of the Ce–Cr coating. At the same time, interfacial transition layer consisting of Ni-Cr-Fe and [Fe,Ni] is formed around the interface of Ce–Cr coating and substrate to facilitate metallurgical bonding, resulting in enhanced interfacial bonding between the coating and substrate.