Abstract:The ion implantation of 2×10¹⁶ , 5×10¹⁶ and 1×10¹⁷ Ce⁺/cm² to Ni₂₀Cr alloy can significantly decrease its oxidation rate at 1 000 ℃ and 1 100 ℃, and improve the adhesion of oxide scales. The influence of Ce ion implantation on the binding energy of alloying elements has been studied by Ion Microprobe Miss Analyzer (IMMA). The binding energy of Cr⁺ in the implanted layer of the alloy decreases, which promotes the protective Cr₂O₃ to form quickly during the initial oxidation stage. However the binding energies of Cr⁺ and Ni⁺ in the oxide scales increase, and the outward diffusion of Cr³⁺ and Ni²⁺ through the oxide scales is suppressed. This result may be related to changing the concentration of defects due to Ce ion implantation. After cyclic oxidation at 1 000 ℃ for 270 times, the beneficial effect of Ce on the resistance to oxidation is still obvious.

Key words: oxidation cerium Ni₂₀Cr alloy ion implantation