表面Ni-Al鍍層對T91鍋爐用鋼抗高溫氧化之研究

Effect of Ni-Al Surface Coatings on High Temperature Oxidation of T91 Boiler Steels

本研究主要探討9Cr-1Mo鍋爐用鋼（T91）以及施以表面Ni-Al改質（T91-NA）鋼材在650~ 850℃空氣條件下的高溫氧化行為。研究結果顯示，T91在650℃和T91-NA在650 ~ 850℃下皆仍遵守拋物線律，但T91在750℃及850℃為加速氧化反應。另一方面，T91-NA在所有溫度下皆有保護性良好的氧化鋁層（α-Al2O3）生成，致使合金的氧化速率明顯降低。

The high temperature oxidation behavior of 9Cr-1Mo alloys (T91) and the alloys with Ni-Al surface coatings (T91-NA) were studied over the temperature range of 650 ~ 850 ℃ in dry air. The results showed that the oxidation kinetics of T91 followed a parabolic rate law at 650 ℃. However, the breakaway kinetics was observed at 750 ℃ and 850 ℃. In addition, the oxidation kinetics of T91-NA followed the parabolic-rate law at temperatures ranging from 650 to 850 ℃. The scales formed on T91-NA consisted of an exclusive α-Al2O3, of which the formation was responsible for the reduction in oxidation rate of the T91-NA alloy, as compared with the rate of the T91 alloy.