Oxidation of Nickel-Coated AISI 430 Alloy: Effect of Pre-oxidation and Fe 0.5 Ni 0.5 Inter-diffusion Layer

The oxidation behavior of nickel (Ni)-coated AISI 430 alloy was investigated at 800 °C in moisture-saturated (~ 3% H2O) air. Effects of pre-oxidation of AISI 430 in air and inter-diffusion layer (Fe0.5Ni0.5) of Ni-coated AISI 430, in dilute hydrogen (Ar–3%H2) at 800 °C, on the oxidation behavior were also studied. Microstructure, elemental chemistry, and compound/oxide formation across the reaction zones/oxide layer were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques. Multilayered oxides/reaction zones were found for all the samples. Ni-coated AISI 430 exhibits the lowest chromium diffusion into the oxide scale from the AISI 430/oxide scale interface. Pre-oxidation of AISI 430 and inter-diffusion of Ni-coated AISI 430 show excessive chromium diffusion into the reaction zone/oxide scale and interfacial porosity.