Oxidation behavior of TiAlZrCr/(Ti, Al, Zr, Cr)N gradient films deposited by multi-arc ion plating

The two Ti-Al-Zr targets and one pure Cr target were used to prepare the TiAlZrCr/(Ti, Al, Zr, Cr)N gradient films on high speed steel (W18Cr4V) substrates by multi-arc ion plating technique. Short-term isothermal (at 600 degrees C, 700 degrees C, 800 degrees C and 900 degrees C for 4 h) and long-term cyclic (at 700 degrees C and 800 degrees C for 100 h) high temperature oxidation behavior of the gradient films were studied. Then the oxide scales formed on the film specimens were characterized by scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy (EDS) and X-ray diffraction (XRD). It was showed that, under short-term isothermal condition, the high temperature oxidation resistance of the gradient film was excellent up to 800 degrees C and an oxide scale comprising TiO2 was observed. On the other hand, under long-term cyclic high temperature condition, the oxidation resistance of the gradient film was excellent at about 700 degrees C.