熔盐热腐蚀的电化学交流阻抗谱研究

采用电化学阻抗谱技术研究了Ｎｉ３Ａｌ、ＩＮ１００和ＩＮ７３８合金在７００℃熔融（Ｎａ，Ｋ，Ｌｉ）２ＳＯ４中的腐蚀行为．结果表明，Ｎｉ３Ａｌ和ＩＮ１００合金的腐蚀呈典型的扩散控制特征，在合金表面形成疏松的腐蚀层；而ＩＮ７３８合金因在表面形成保护性的Ｃｒ２Ｏ３膜，腐蚀不受扩散控制．提出了等效电路并计算了相应的电化学参数．

Electrochemical Impedance of Molten Salts Induced Hot Corrosion

Electrochemical impedance technique was employed to study corrosion behaviors of Ni-3Al, IN100 and IN738 alloys in molten (Na, K, Li)_2SO_4 at 700 ℃. The Nyquist plots for Ni-3Al and IN100 alloys have the characteristics of diffusion controlled reaction. But, the corrosion reaction for IN738 alloy is not controlled by the diffusion of oxidants. The equivalent circuits were proposed, and the parameters in circuits were also calculated. Ni-3Al and IN100 alloys suffer from catastrophic corrosion due to the formation of a porous corrosion layer. IN738 alloy has excellent corrosion resistance because of the formation of a protective oxide scale.