Preparation and high temperature oxidation of AlCrN coatings on the surfaces of Ni-Fe-Cr-based superalloys

An AlCrN coating was prepared on the surface of a Ni-Fe-Cr-based superalloy by cathodic arc ion plating. The morphology, energy spectra, phase composition, and binding energy of the coating surface and interface were analyzed by means of scanning electron microscopy, energy disperse spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The high temperature oxidation resistance and mechanism of the coating were studied by high temperature oxidation tests at 800 and 900℃. It is found that the coating is mainly composed of Al, Cr and N elements, showing strong preferred orientation of AlN after adding Al element. The peak spectrum of Al2p is Al-N and Al-O binds, the peak spectrum of Cr2p is Cr-O and Cr-N binds, and the peak spectrum of N1s is in the form of Cr-N and Al-N, also contains a small amount of N-Cr-O and N-Al-O bonds. The oxide in the coating surface is Cr₂O₃ after high temperature oxidation, which has good protective effect on the Ni-Fe-Cr-based superalloy.