It can be divided into the following four types:
(1) Alkaline cyanide plating bath.
(2) Alkaline sulfate plating bath.
(3) Acidic boron fluoride salt plating bath.
(4) Neutral sulfate plating bath. The type of plating bath should be selected based on the shape of the plated parts, the requirements of the plating layer, and the uniformity of the plating bath. Generally, acid plating baths are used for single-shaped plating parts, while alkaline cyanide plating baths are used for complex-shaped prosthetic parts. The coating in the alkaline plating bath has fine crystallization and good uniformity, but it is toxic and troublesome to deal with the waste liquid. The electroplating bath is unstable and the cathode and anode current efficiencies are different. Carbon dioxide in the air will form sodium carbonate and hydrogen cyanide in the plating bath. Acidic plating baths are less susceptible to hydrogen embrittlement.