Electroplating of Refractory Metals in Molten Salts: A Review

Molten salt has a wide electrochemical window and excellent ion conductivity, which makes it possible to electrodeposit refractory metals in molten salt to obtain coatings. Meanwhile, the electroplating rate will be faster as a result of the high temperature in the molten salt. However, due to the complex chemical/electrochemical reaction of refractory metal ions with multiple valence states in molten salt, the precise control of electroplating is difficult. In this paper, the electrode reaction process, grain nucleation and growth model, and regulation mechanism of coatings are discussed. Subsequently, the research progress of various refractory metal coatings is reviewed, and the effects of technical parameters on the morphology and properties of the coatings are discussed. The challenges faced by refractory metal molten salt electroplating are summarized and potential future research directions are also proposed.