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 ℃,700 ℃,800 ℃ and 900 ℃ for 4h) and long-term cyclic (at 700 ℃ and 800 ℃ for 100h) 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 ℃ 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 ℃.
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