Abstract:The influence of Ce implantation into preformed scales with a dose of 1×1017 ions/cm2 on the subsequent oxidation behavior of GH128 alloy at 1 000 ℃ in air was investigated. The pre-oxidation was carried out at 1 000 ℃ in air for 1 h and 5 h respectively. Cr2O3, NiO and NiCr2O4 formed on the surface of all specimens. Ce implantation decreased the subsequent oxidation rate of both the alloy and the 1 h pre-oxidized alloy, however, had no effect on that of the 5 h pre-oxidized alloy. The beneficial effect was most obvious in the directly implanted alloy. During the cyclic oxidation for 600 h, Ce implantation for all specimens with or without preferential oxidation played a similar beneficial effect on the oxide spallation resistance. The results indicate that Ce incorporated into the oxide scales affects the diffusion of the reaction species to some extent, the wavy interface and small grain structure make a significant contribution to improving the spallation resistance of the oxide scales.

Key words: oxidation; Ce; ion implantation; GH128 alloy