Abstract:FeAlMoCrC and FeAlNiMoCrC coatings were prepared by spraying two kinds of self-developed wire onto the surface of 45 steel with high velocity arc spraying technology. The microstructure of the two coatings was analyzed and the cyclic oxidation behavior of the two coatings and substrate at 700 ℃ was investigated. The results show that the FeAlMoCrC coating mainly consists of three intermetallic compounds: FeAl, FeCr, and Fe2AlV, and two oxide phases of Al2O3 and Fe3O4. The FeAlNiMoCrC coating is mainly composed of four intermetallic compounds: AlNi, AlCr2, FeNi3 and Fe8Cr, and three oxide phases of Al2O3, Cr2O3 and Fe3O4. According to the calculation of the porosity of the coating, it is found that the internal porosity of the coating is low, all of which are less than 10%. After fitting and analyzing the oxidation weight gain curve, it is found that the FeAlNiMoCrC coating has lower oxidation rate constant, larger oxidation index, slower oxidation rate and better oxidation resistance. Through phase and microstructure analyzing, it is considered that the low porosity of the coating and the formation of continuous and dense oxide films such as Al2O3, Cr2O3 and Fe3O4 in the oxidation products contribute to the improvement of high temperature oxidation resistance.