During World War II, with most cadmium and cadmium plating going toward the war effort, the plating industry investigated alternatives -- most notably, tin zinc compounds -- that would provide suitable finishes and corrosion protection. But by the end of the war, the search had accomplished little, and with the return of a plentiful supply of cadmium, it was once again the coating of choice, providing an excellent balance of rust prevention, cost effectiveness, and finish appearance.
Now, cadmium is in a war of its own, under siege as a toxic and hazardous material and a possible carcinogen. Facing escalating costs for handling, disposal, and implementing environmental protective measures, as well as worker health concerns, entire industries, such as the automotive sector, have banned cadmium plating while others have put in place severe restrictions and limits on its use. With decreasing demand for cadmium, yet with few alternatives available, plating services both large and small are once again searching for the balanced solution.
Unlike 60 years ago, however, the chemical companies supporting the plating industry have taken the issue to heart. Aldoa (Detroit, MI) has been a pioneer in the development of alternative materials and processes. With its close ties to Detroit and the Midwest area plating firms, where the bulk of the work is auto related, Aldoa was one of the first chemical firms to offer automakers a viable alternative to cadmium plating: its acid zinc-nickel process, Novalyte ZNA, is one of the most widely used substitutes. With more than five years of experience providing Novalyte ZNA, Aldoa has fine tuned both product and process. And that, according to Rick Keith, president of Wolverine Plating (Roseville, MI), was a major factor in his selection of Novalyte ZNA.
"We were the first plating company to use their new product," says Keith, "but right from the start it was apparent that they had done their homework. They [Aldoa] demonstrated a level of expertise and knowledge about the product, and about the process, that no other company could." Some Wolverine Plating products coated with Aldoa's Novalyte ZNA plating system are shown in the photo.
Novalyte ZNA is a two-part plating system for barrel or rack plating applications that deposits a mirror-bright zinc/nickel (10%-20% nickel) finish. Formulated to exacting chemical specifications, and combined with Aldoa's extensive process development, in-depth application analysis, and proprietary additives, Novalyte ZNA assures uniform thickness, finish, and corrosion protection. When combined with the appropriate Aldoa chromate, it withstands more than 2000 hours of grueling, red rust salt spray tests.
Aldoa's Novalyte AZN is an alkaline non-cyanide zinc-nickel alloy plating process that deposits an 8%-14% nickel content in the finish, establishing a greater level of corrosion protection than other commercially available processes, which typically give 4%-7% nickel content. Novalyte AZN is also a bright finish and readily accepts different types of post treatment.
"We compared four other suppliers' productswe found Novalyte ZNA was the best product as to uniformity, coverage, and control of finish and thickness," says Keith. "And, because of Aldoa's extensive development program, our transition from cadmium to the zinc nickel alloy was not a trial and error process. It went smoothly, with no compromise in our quality."
