Getting rid of heavy metals Traditional coating systems use heavy metals - such as zinc phosphate, iron phosphate or chrome - to enable the inorganic and organic substances to be able to stick to one another. Phosphates released into the environment causes various algal blooms in lakes and rivers, damaging aquatic plant and animal life. Also used in the process are solvents that have in the past polluted the environment.   Two-step process Unlike conventional methods, Zelisko and Vanchem’s system involves a two-step process. First, a base layer is applied to the metal. Water mixed with silica, which is basically sand, is sprayed onto the metal, creating a chemical bond with the metal. This cleans the metal but also deposits silica onto the surface. This coating not only protects the metal but acts as a primer for the second layer, which is designed to bond well to paint. The second layer contains polysilicates, the basis of which is silicon, "the second-most abundant element in the Earth’s crust,” says a company report. Silicates can be modified to stick to both metals and paints.

Three times as good as required
When the industry wants to determine whether or not a coating product is effective, the treated metal sheets are put into salt-spray chambers, where a fine mist of salt water is continually sprayed onto the metal until it starts to show signs of corrosion. The industry standard is around one thousand hours, says Zelisko. "Our coatings ranged anywhere from 1,800 to 3,000 hours, in some cases almost three times as good as what the industry requires.” When coming in contact with metal, salty water acts as a type of catalyst, enabling oxygen to mix with metal, resulting in corrosion.
The team received the patent for "Greencoat" silane-based pretreatment on Aug. 2 in the United States, with Canadian and European patents pending.
Saving money in the long run
The Brock-Vanchem innovation is a sign of the times, says Ian McLeod, vice president of Vanchem Performance Chemicals. "The industry has switched over to greener technologies; they want to get rid of the heavy metals,” he says. "Large corporations and companies want to be environmental stewards. They want to be able to say, ‘look at what we’re doing, we’ve replaced the old zinc phosphate technology with a new silane-based technology that doesn’t have any environmental impacts.’” McLeod says that the initial price of a ‘green’ coating may be more expensive than a zinc phosphate one. But, factoring in environmental disposal, maintenance and other costs associated with non-green coatings, companies could save money in the long run.