Oxidation behavior of the compound Ti-Al-Si-N/1Cr11Ni2W2MoV at 800°C for 1000h in air

A Ti–Al–Si–N coating was deposited on 1Cr11Ni2W2MoV stainless steel by arc ion plating(AIP) with a Ti60Al30Si10 cathode, and the prolonged oxidation behavior of the compound Ti–Al–Si–N/1Cr11Ni2W2MoV at 800°C in air was investigated by TEM, SEM/EDAX, EPMA and XRD. For comparison, the oxidation of the 1Cr11Ni2W2MoV steel at 800°C was also conducted. The results show that after oxidation at 800°C for 1000h, the compound Ti–Al–Si–N/1Cr11Ni2W2MoV showed excellent oxidation resistance and formed a multilayered scale. They are the top porous surface layer of TiO2, followed by a dense layer rich in Al2O3, a mixture oxides dense layer mainly composed of TiO2, SiO2 and some chromium oxide, and a bottom dense lay of chromium oxide due to the selective oxidation of the substrate. The addition of Si in the Ti–Al–N coating can promote the outwards diffusion of Al and hinder the outwards diffusion of Ti remarkably, and thus form dense and protective scale. The oxidation mechanism of the compound Ti–Al–Si–N/Cr11Ni2W2MoV at 800°C for prolonged time in air was discussed.