MIT Replaces Chromium as Coating Material

Researchers at the Massachusetts Institute of Technology recently made the first steps towards changing the 40-year-old habit of coating metal hardware in chromium, when they showcased a new type of alloy, made entirely of nickel and tungsten. The material has the same protective effects on the surfaces it's supposed to protect, but lasts even longer than chromium does, and does not affect the environment as much during the production process. Thus, everything from car bumpers to bathroom fixtures could soon be covered with the new alloy, rather than the outdated chromium.

“People have been trying to replace it for a very long time. The problem is that it's the only plated metal coating that has all of these properties – hardness, long-lasting shine and corrosion protection,” MIT Associate Professor of Materials Science and Engineering Christopher Schuh explained. The expert led a team of MIT scientists in developing the new nickel-tungsten alloy, which is currently already undergoing testing in a fleet of trucks, at a location in the United States. If the alloy fares well, chances are it will soon replace chromium in car parts, faucet fixtures, and in other applications as well.

One of the main drawbacks of the chromium industry, which is currently worth some $20 billion, is that it creates the cancer-triggering hexavalent chromium ions, which can easily contaminate groundwater for extensive periods of time. The liquid baths in which objects have to be soaked in order to be plated with the chemical are fatal if workers come in contact with them. All these drawbacks of the aging industry could be easily surpassed if tungsten-nickel was introduced as the main plating material for metal parts in most applications.

Schuh and his team have shown that the new alloy has the ability to not decompose under heat, and that it also remains stable for indefinite periods of time at room temperature. “Not only do you get rid of the environmental baggage, but you make a better product as well,” the expert added. He described the new technology and its production process this spring at the 2009 Wulff Lecture, hosted by the MIT Department of Materials Science and Engineering. Other details were also published in a number of prestigious journals over the year.