Microstructure and High Temperature Oxidation Resistance of FeNiCrTiB/Cr₃C₂ 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 200 h, the weight gain of the FeNiCrTiB/Cr3C2 coating was 1.58 mg·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.