Shuichi Arikawa1, Seiichi Muneki2, Hiroshi Okubo2, Fujio Abe2 and Takao Yakou3
1Graduate School of Engineering, Yokohama National University, Yokohama 240-8501
The formation process of a FeAl coating on carbon-nitrogen free Fe-12Ni-9Co-10W austenitic alloy by aluminizing treatment has been investigated. After heating to 1173 K, a pure Al foil on the base alloy surface changed to a FeAl3 surface layer and a FeAl thin layer. After that, in early stage of diffusion treatment at 1173 K, the surface layer changed to Fe2Al5. Thickness of the FeAl layer expanded from the boundary between the surface layer and the base alloy to the surface. The FeAl monolayer was formed after the diffusion treatment for 10.8 ks. The surface exhibited acicular morphology of the FeAl3 layer. This acicular structure changed to relatively flat as the diffusion process proceeds. After the diffusion treatment at 1173 K for 302 ks, the FeAl surface layer of 80 μm thickness was formed on the base alloy from the initial stage of the pure Al foil of 50 μm thickness. Hardness of the FeAl layer which was formed at 1173 K and 1373 K has been investigated. The FeAl layer with approximately 40 at%Al content which was formed at 1173 K was harder than that formed at 1373 K.
aluminize, FeAl3, Fe2Al5, FeAl, aluminum diffusion, coating, austenite steel, advanced-ultra super critical power plant
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