Effect of Rare Earth Y on High Temperature Oxidation Resistance of AISI430 Stainless Steel

Different doses of rare earth Y were implanted on the surface of AISI430 alloy by ion implantation and the effect of Y on the high temperature oxidation resistance of AISI430 alloy was investigated,. The characteristics of oxide scales were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD). The oxidation process was observed in situ by VL200DX ultra high temperature confocal laser scanning microscope. The results show that when the dose of rare earth Y implanted on the surface of the alloy is 6×1017 ions/cm2 the mass gain and the amount of spalling per unit area of Y-implanted samples reduce by 43.7% and 78.4%, respectively, compared with the un-implanted Y samples. Y ions on the alloy surface oxidize to Y2O3 preferentially, which promotes the formation of oxide film and inhibits the grain growth. In addition, Y2O3 at the grain boundary hinders the diffusion of metal cations through the grain boundary. Importantly, Y substitutes for Mn2+and Cr3+ in MnCr2O4 spine, resulting in the formation of vacancy defect. It relieves the internal stress of oxide layer and reduces the generation of cracks and holes, making oxide layer bond with the substrate closely. © 2021, Science Press. All right reserved.