This type of cadmium plating has a phosphate supplementary colorization and is usually employed as a paint base. Cadmium plating classifications are divided into 1, 2, and 3, based on the thickness of the coating. For example, class 1 is a coating of 0.0005 in., class 2 is 0.0003 in., and class 3 is rated at 0.0002 in. Cadmium Plating Expertise