IC21合金作为一种新型Ni₃Al基单晶高温合金，因其具有高熔点、优异的高温性能和抗蠕变能力，已成为新一代航空发动机涡轮导向叶片的理想材料。然而，涡轮导向叶片通常具有深小孔和深窄槽等复杂结构，传统加工方法难以满足高效加工要求。电解加工因其无工具磨损、高材料去除率以及不产生切削应力和热效应等优势，成为加工此类复杂结构的主要选择。本工作研究了IC21镍基单晶合金在NaCl和NaNO₃电解液中的电解加工电化学溶解行为。通过线性扫描伏安极化曲线测量，分析了IC21合金在不同电解液中的电化学反应特性。此外，通过电流效率测量、表面微观形貌分析，探讨了不同电解液和电流密度条件下合金的溶解特性和选择性溶解现象。研究表明：IC21合金在NaCl和NaNO₃电解液中均表现出典型的钝化-超钝化转变现象，其中NaNO₃电解液中形成的氧化层表现出更高的稳定性。电流效率测量表明，IC21合金在NaCl电解液中的溶解效率较为稳定，而在NaNO₃电解液中，溶解效率随着电流密度的增加逐渐下降，表现出与传统理论不同的特性。通过溶解表面形貌分析，进一步揭示了IC21合金在电解加工过程中存在选择性溶解现象，并探讨了其微观机制。基于这些实验结果，建立了不同电解液和电流密度条件下的电化学溶解行为模型，为IC21合金电解加工工艺的优化提供了理论依据。

IC21 alloy， as a new Ni₃Al-based single crystal superalloy， has become an ideal material for manufacturing a new generation of aero-engine turbine guide vanes due to its high melting point， excellent high-temperature performance， and creep resistance performance. However， turbine guide vanes have complex structures， such as deep holes and deep and narrow slots， which are difficult to be processed efficiently by traditional machining techniques. Electrochemical machining has become the main method for processing such complex structures due to its advantages， such as no tool loss， high material removal rate， and no cutting stress and thermal effect. This paper focuses on the electrochemical dissolution behavior of IC21 nickel-based single crystal alloy in NaCl and NaNO₃ electrolytes. The electrochemical reaction characteristics of IC21 alloy in different electrolytes are analysed by linear scanning voltammetric polarisation curve measurements. In addition， the dissolution characteristics and selective dissolution phenomena of the alloy under different electrolytes and current densities are investigated by current efficiency measurements and surface micro-morphology analysis. It is shown that IC21 alloy exhibits typical passivation-super-passivation transition phenomena in both NaCl and NaNO₃ electrolytes， in which the oxide layer formed in NaNO₃ electrolyte exhibits higher stability. Current efficiency measurements show that the dissolution efficiency of IC21 alloy is more stable in NaCl electrolyte， and the dissolution efficiency in NaNO₃ electrolyte gradually decreases with the increase of the current density， which exhibits different characteristics from the traditional theory. The dissolution surface morphology analysis further reveals the existence of the selective dissolution phenomenon of IC21 alloy under ECM conditions， and its microscopic mechanism is discussed. Based on the above experimental results， a theoretical model of electrochemical dissolution of IC21 alloy under different electrolyte and current density conditions is established， which provides a theoretical basis for the development and application of ECM processes for IC21 alloy.