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