Isothermal and cyctic oxidation behaviours of pure and yttrium-implanted nickelwere studied at 1000℃ in air.Scanning electronic microscopy (SEM) and transmission electronicmicroscopy (TEM) were used to examine the micro-morphology and structure of oxide scalesformed on the nickel substrate.It was found that Y-implantation significantly improved the anti-oxidation ability of nickel in both isothermal and cyclic oxidizing experiments.Laser Ramanmicroscopy was also used to study the stress status of oxide scales formed on nickel with andwithout yttrium.The main reason for the improvement in anti-oxidation of nickel was that Y-implantation greatly reduced the growing speed and grain size of NiO.This fine-grained NiO oxidefilm might have better high temperature plasticity and could relieve parts of compressive stressby means of creeping,and maintained a ridge character and a relatively low internal stress level.Hence yttrium ion-implantation remarkably enhanced the adhesion of protective NiO oxide scaleformed on the nickel substrate.
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