First Environmentally Friendly Protective Chromium Coating for Aluminum Due on Market Soon.

The world's first protective chromium-based metal finish coating (mainly for aluminum) that is both environmentally benign and highly effective will be commercially available later this year as a result of a licensing arrangement between the US Navy's Air Warfare Center and Metalast International, Inc. of Minden, Nevada.

The coating for anodizing, called trivalent chromium protection, has the potential to replace the industry leading, but highly toxic, hexavalent chromium coating. Hexavalent chromium has been in widespread use worldwide for more than half a century, but is hazardous for both humans and the environment.

Fig. 1 - coated bracket

"This coating offers everything - the corrosion protection of hex chrome, without the hazard. We're thrilled to be the first company anywhere to bring it to market," said Sjon Westre, vice president of technical support at Metalast. "The product is available later this year but we've already got customers lining up," he said.

Because oof its strength and light weight, aluminum is the metal of choice for airplanes, automobiles, appliances, construction materials, satellites, and many other household and military products. Because it corrodes easily when exposed to the elements (especially salt-laden air near coasts), aluminum must be coated to extend its useful life. In order for protective coatings to adhere to aluminum's inherently non-stick surface, the metal must be pretreated with a substance to which paints and other metal finishes can form a lasting bond.

Enter trivalent chromium, a corrosion prevention coating developed and patented by the Naval Air Systems Command (NAVAIR) of Patuxent River, Maryland. This compound is highly effective but far less toxic than its cousin, hexavalent ...