Electrochemical Dissolution Behavior of GH4169 and K418 Superalloy in NaNO₃ Solution at Low Current Density

In the process of electrochemical machining (ECM), the machining voltage is usually 6–26 V. For many workpieces with complex shapes, some positions will be dissolved under the electrolytic environment of low current density caused by low voltage. This phenomenon is called undesirable dissolution. This paper mainly studies the electrochemical dissolution of GH4169 and K418 superalloys in NaNO3 solution at low current density. The dissolution experiment was carried out at different dissolution time. The processed samples were observed and analyzed by scanning electron microscope and energy dispersive instrument. The surface properties of the alloys dissolved at low current density and the reasons for this dissolution phenomenon were analyzed.