摘要
The oxidation behavior of Co 40Cr alloy with and without yttrium implantation was studied at 900 ℃ in the air. Scanning electron microscopy(SEM), secondary ion massive spectroscopy(SIMS), transmission electron microscopy(TEM) and high resolution electron microscopy(HREM) were used to study the forming mechanism of oxide film on the alloy. It is found that the binding energy of Cr on the alloy surface is decreased by yttrium implantation, thus the formation of protective Cr 2O 3 film on the substrate is accelerated. In the mean time, the binding energy of Cr inside the oxide scale is increased by yttrium implantation, and this would reduce the Cr 3+ cation diffusion through the film. Yttrium implantation decreases the grain size and the growing speed of oxide film. SIMS and TEM/HREM results show that some yttrium exists as small YCrO 3 particles at Cr 2O 3 grain boundary near the oxide/gas interface, and a few small Y 2O 3 particles exist near the substrate/oxide interface. Besides, yttrium may also segregate to Cr 2O 3 grain boundary as Y 3+ , reduce Cr 3+ cation diffusion and change the mechanical properties of the oxide film. The ability of anti oxidation of Co 40Cr alloy is greatly improved by yttrium implantation.
The oxidation behavior of Co 40Cr alloy with and without yttrium implantation was studied at 900 ℃ in the air. Scanning electron microscopy(SEM), secondary ion massive spectroscopy(SIMS), transmission electron microscopy(TEM) and high resolution electron microscopy(HREM) were used to study the forming mechanism of oxide film on the alloy. It is found that the binding energy of Cr on the alloy surface is decreased by yttrium implantation, thus the formation of protective Cr 2O 3 film on the substrate is accelerated. In the mean time, the binding energy of Cr inside the oxide scale is increased by yttrium implantation, and this would reduce the Cr 3+ cation diffusion through the film. Yttrium implantation decreases the grain size and the growing speed of oxide film. SIMS and TEM/HREM results show that some yttrium exists as small YCrO 3 particles at Cr 2O 3 grain boundary near the oxide/gas interface, and a few small Y 2O 3 particles exist near the substrate/oxide interface. Besides, yttrium may also segregate to Cr 2O 3 grain boundary as Y 3+ , reduce Cr 3+ cation diffusion and change the mechanical properties of the oxide film. The ability of anti oxidation of Co 40Cr alloy is greatly improved by yttrium implantation.
