The influence of cadmium on corrosion
The influence of cadmium on corrosion. Cadmium is mainly used in the metal industry as a galvanic coating. Therefore, during storage, you can often find steel elements coated with this metal to protect against corrosion. The cadmium coating corrodes itself and becomes covered with white products, most often the hydroxide, carbonate, chloride; or cadmium sulphate depending on the type of atmosphere acting on the cadmium. In most of the stored electrical equipment, the presence of white corrosion products on cadmium parts is undesirable due to the loss of electrical conductivity of these parts.. Due to the high humidity of tropical zones, cadmium coatings corrode in them despite, that they are more resistant to moisture than zinc. In an industrial atmosphere, cadmium undergoes 2 – 3 times faster corrosion than zinc. The cadmium coating can be made resistant to atmospheric corrosion by varnishing. Sometimes, when stored in mild climatic conditions, it is sufficient to passivate the galvanic coating of cadmium in chromate solutions, similarly to zinc. Apparatus having cadmium elements, should be protected against corrosive agents by using packaging ensuring low humidity. The use of cadmium-plated products with volatile corrosion inhibitors is impossible due to their corrosive effect on the cadmium coating.