The study investigated the oxidation behavior of T91 steel modified with Al(T91-Al)and Si(T91-Si)in lead-bismuth eutectic(LBE)at 450℃under oxygen-saturated conditions(10^(−7)-10^(−8)wt.%)and oxygen-controlled conditi...The study investigated the oxidation behavior of T91 steel modified with Al(T91-Al)and Si(T91-Si)in lead-bismuth eutectic(LBE)at 450℃under oxygen-saturated conditions(10^(−7)-10^(−8)wt.%)and oxygen-controlled conditions(3.2×10^(−4)wt.%).Advanced characterization techniques were employed to under-stand the thermodynamic and kinetic mechanisms of enhanced oxidation properties of the modified T91 steel.The results indicate that the oxidation resistance of the materials follows this order:T91<T91-Al<T91-Si.Noteworthy,the oxidation resistance of T91-Si material exhibited minimal correlation with dissolved oxygen.Under oxygen-controlled conditions,the oxide film of T91 and T91-Al was attacked and broken by LBE,with the former eventually peeling off.In contrast,both materials showed significant ox-ide film thickening,except T91-Si under oxygen-saturated conditions.The addition of Al improved the quality of the inner oxide film on T91-Al by generating Al_(2)O_(3),thereby slowing down the diffusion of Fe from the matrix and enhancing oxidation resistance.Conversely,Si actively participated in the oxidation process of T91-Si,slowing down the diffusion of Fe,and facilitating the diffusion of Cr,thereby strength-ening the oxide film protection.Consequently,the oxide thickness of T91-Si material was only 24%of T91 and 35%of T91-Al under saturated oxygen conditions.展开更多
基金financial support from the National Key R&D Program of China(No.2020YFA0405901)the National Natural Science Foundation of China(Nos.52375155 and 51875398).
文摘The study investigated the oxidation behavior of T91 steel modified with Al(T91-Al)and Si(T91-Si)in lead-bismuth eutectic(LBE)at 450℃under oxygen-saturated conditions(10^(−7)-10^(−8)wt.%)and oxygen-controlled conditions(3.2×10^(−4)wt.%).Advanced characterization techniques were employed to under-stand the thermodynamic and kinetic mechanisms of enhanced oxidation properties of the modified T91 steel.The results indicate that the oxidation resistance of the materials follows this order:T91<T91-Al<T91-Si.Noteworthy,the oxidation resistance of T91-Si material exhibited minimal correlation with dissolved oxygen.Under oxygen-controlled conditions,the oxide film of T91 and T91-Al was attacked and broken by LBE,with the former eventually peeling off.In contrast,both materials showed significant ox-ide film thickening,except T91-Si under oxygen-saturated conditions.The addition of Al improved the quality of the inner oxide film on T91-Al by generating Al_(2)O_(3),thereby slowing down the diffusion of Fe from the matrix and enhancing oxidation resistance.Conversely,Si actively participated in the oxidation process of T91-Si,slowing down the diffusion of Fe,and facilitating the diffusion of Cr,thereby strength-ening the oxide film protection.Consequently,the oxide thickness of T91-Si material was only 24%of T91 and 35%of T91-Al under saturated oxygen conditions.
