Microstructure and High Temperature Oxidation Resistance of FeNiCrTiB/Cr_3C_2 Coating Deposited by High Velocity Arc Spray

The metal-ceramic composite coating FeNiCrTiB/Cr3C2 with high temperature corrosion resistance was prepared by high velocity arc spray(HVAS).The optical microscopy,scanning electron microscopy and X-ray diffraction were used to analyze microstructure and oxidation products of the coating.The high temperature oxidation resistance of FeNiCrTiB/Cr3C2 coating was compared with that of bare 20G steel.The high temperature oxidation mechanism of the coating was investigated.The results showed that microstructure of HVAS FeNiCrTiB/Cr3C2 coating was the typical layer structure.Some pores and oxides were distributed on coating.After oxidation in 650℃ for 200h,the weight gain of the FeNiCrTiB/Cr3C2 coating was 1.58mg·cm-2,which was much less than that of the bare 20G steel(24.85 mg·cm-2).The formation of the compact Fe,Cr composite oxides was responsible for the protection of the coating from further oxidation.