WHAT TYPE OF PLATING IS RIGHT FOR YOUR PARTS?
Zinc plating is the most common and economical type of plating. Most fasteners and hardware that is found in the local hardware store has been zinc plated. Zinc plating is a sacrificial coating designed to corrode so the part does not. The limitations of zinc are that when the plating begins to corrode the zinc rust is plentiful and unsightly. Zinc Plating is available in clear (silver color), blue, yellow, black and olive drab green. Trivalant chromates are used if requested. See salt spray article for comparing chromate colors.
Cadmium plating is superior to zinc for corrosion protection. It is used in harsh environments and commonly used in aerospace applications. It is especially good in marine and salt environments. Since the common corrosion test is a salt spray test, cadmium performs very well. It usually will offer double the corrosion resistance as zinc. It is available in clear, yellow, olive drab and black. See comparison chart.
Tin-Zinc was developed as a direct replacement for cadmium. Tin-Zinc offers all the advantages of cadmium like its extreme resistance to corrosion, but it does not have the “toxic” label associated with cadmium. Tin-Zinc has become a preferred coating in the automotive industry due to its high corrosion resistance and its good electrical conductivity. Tin-Zinc will usually provide double the corrosion resistance of cadmium. It is available in yellow and clear trivalent for RoHS compliance. To learn more, refer to the article on Tin-Zinc.
Zinc Nickel Plating
Zinc Nickel was also developed as a cadmium replacement. Amazing corrosion resistance and its ability to handle high temperatures is making this plating very popular with all the automotive companies. Zinc Nickel can withstand from 1000 to 2000 hours of salt spray testing. Zinc Nickel Plating on steel parts performs as well or better than most stainless steel parts. Zinc Nickel is processed using only trivalent chromates so it complies with all the directives that restrict the use of hexavalent chrome. It is available in clear and black colors. To learn more, refer to the article on Zinc Nickel.