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 mi...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.展开更多
The isothermal and cyclic oxidation behaviors of bulk pure nickel and its Ni-0.5Y microcrystal coating sputtered by magnetron at 1 000 ℃ in air were studied. The scanning electronic microscopy (SEM) and transmission ...The isothermal and cyclic oxidation behaviors of bulk pure nickel and its Ni-0.5Y microcrystal coating sputtered by magnetron at 1 000 ℃ in air were studied. The scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the structures of the coating and the NiO oxide films. The laser Raman spectrum was also used to measure the stress level in NiO films formed on bulk nickel and the coating. It is found that the Ni-0.5Y microcrystal coating has lower oxidation rate, and the grain size of NiO formed on Ni-0.5Y coating is also relatively smaller than that formed on bulk nickel. Meanwhile, the compressive stress level of oxide film formed on Ni-0.5Y coating was lower than that formed on bulk nickel, and the high temperature plasticity of oxide film was much improved in coating case. The improvements of anti-oxidation properties of the sputtered Ni-0.5Y coating are due to the microcrystal structure and yttrium.展开更多
基金National Natural Science Foundation of China(No.29231011)National Natural Science Foundation of Colombia(No.M018327)
文摘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.
文摘The isothermal and cyclic oxidation behaviors of bulk pure nickel and its Ni-0.5Y microcrystal coating sputtered by magnetron at 1 000 ℃ in air were studied. The scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the structures of the coating and the NiO oxide films. The laser Raman spectrum was also used to measure the stress level in NiO films formed on bulk nickel and the coating. It is found that the Ni-0.5Y microcrystal coating has lower oxidation rate, and the grain size of NiO formed on Ni-0.5Y coating is also relatively smaller than that formed on bulk nickel. Meanwhile, the compressive stress level of oxide film formed on Ni-0.5Y coating was lower than that formed on bulk nickel, and the high temperature plasticity of oxide film was much improved in coating case. The improvements of anti-oxidation properties of the sputtered Ni-0.5Y coating are due to the microcrystal structure and yttrium.
