Oxidation behavior of arc-sprayed FeMnCrAl/Cr3C2-Ni9Al coatings deposited on low-carbon steel substrates

FeMnCr/Cr3C2 and FeMnCrAl/Cr3C2 coatings, using Ni9Al arc-sprayed coating as an interlayer on low-carbon steel substrates, were deposited by high velocity arc spraying (HVAS) on the cored wires. The high temperature oxidation behavior of the arc-sprayed FeMnCrAl/Cr3C2-Ni9Al and FeMnCr/Cr3C2 coatings on the low-carbon steel substrates was studied during isothermal exposures to air at 800 degrees C. The surface and interface morphologies of the coatings after isothermal oxidation after 100 h were observed and characterized by optical microscopy, field emission scanning electron microscope, energy dispersion spectrum, and X-ray diffraction. The results showed that the oxidation weight gains of the coatings were significantly lower than that of the low-carbon steel substrate. Moreover, the FeMnCrAl/Cr3C2-Ni9Al coating registered the lowest oxidation rate. This favorable oxidation resistance is due to the Al and Cr contents of the aforementioned coating that inhibits the generation of Fe and Mn oxides. This is attributed to the interdiffusion between the substrates and the Ni9Al arc-sprayed coating, which can convert the mechanical bonding between substrates and coatings into a metallurgical one, thereby inhibiting the oxidation of interface between the low-carbon steel and the coating. (C) 2010 Elsevier B.V. All rights reserved.