Cadmium is a soft, malleable metal that is very light in color. In the plating industry it is used as sacrificial coating. Ideal for a corrosive environment, cadmium can protect the underlying base metal, such as steel, even when scratched or corroded.
While the nature of the deposit is well suited for the aerospace industry (particularly landing legs/gears), according to the EPA, cadmium is highly toxic and exposure to this metal and its compounds can cause health related problems including pulmonary irritation, kidney disease, and lung cancer in humans and animals. For these reasons the EPA is encouraging industries to discontinue using cadmium and switch to an alternative deposit.
At SIFCO ASC, we’ve been developing cadmium alternatives since 1992, to meet Boeing’s specifications and demand for an environmentally friendly alternative. Boeing began their research into cadmium alternatives in the early 1970’s as a response to Japan’s ban of the use of cadmium in 1969. According to Mary J. Nelson and Earl C. Groshart of the Boeing Defense & Space Group, “In 1990, Environmental Protection Agency’s (EPA) “33/50” Plan for reduction of 17 chemicals including cadmium and cyanide became a goal for Boeing to reduce its hazardous chemical usage.”
To date, SIFCO ASC has two cadmium alternatives which provide corrosion resistance, lubricity and low hydrogen embrittlement. Zinc-Nickel LHE, Code 4018 and Tin-Zinc, Code 4019 both meet aerospace spec AMS 2451, while 4018 also meets AMS 2417, and 4019 meets AMS 2434.
To determine which deposit is best for your application, contact SIFCO’s Technical Service today, 800-765-4131.