Passivation acts as a protection for zinc and cadmium plated surfaces so that their main task of sacrificial protection is not reduced.
Under conditions such as high humidity or high ambient temperature Zinc and Cadmium coatings can form a self-corroding product commonly known as ‘white rust’. This white rust compromises the protective barrier of zinc or cadmium and can lead to complete failure of the coating, and corrosion of the base metal.
Through passivating zinc and cadmium plated items an additional coating is formed to protect the benefits of the zinc or cadmium plating.
There are two kinds of passivating process;
Full passivation – this provides maximum protection from corrosion and produces an effect which dyes the metal. On pieces for which appearance doesn’t matter this is the most efficient kind of passivation.
To make passivation treatments as effective as possible items being treated must be handled with expert care.