Microstructure and high temperature oxidation resistance of FeMnCrAl/Cr_3C_2 coatings deposited by high velocity arc spraying

FeMnCrAl/Cr3C2coating was deposited on AISI 20 steel substrate by high velocity arc spraying.The microstructure and high temperature oxidation resistance of FeMnCrAl/Cr3 C2 coating were studied by means of optical microscopy(OM),field emission scanning electron microscopy(FE-SEM),energy dispersion spectrum(EDS) analysis and X-ray diffraction(XRD).The oxidation resistance of FeMnCrAl/Cr3 C2 coating was compared with that of FeMnCr/Cr3 C2 coating,316L stainless steel coating and AISI 20 steel.The results show that the three kinds of coatings obviously have better oxidation resistance than that of AISI 20 steel substrate.FeMnCrAl/Cr3 C2 coating exhibits a lower isothermal mass gain than FeMnCr/Cr3 C2 coating and similar to that of 316L stainless steel coating.The formation of compact oxide film containing aluminum and iron-chromium oxide in FeMnCrAl/Cr3 C2 coating is responsible for the protection of the coating from further oxidation,but the protective oxide films are not uniformly distributed due to micro-inhomogeneous composition of the as-sprayed coatings and pores in the coatings.