Chromate Conversion Coating
Vanchem’s new environmentally friendly alternative to chromate conversion coating
Chromate conversion coating technology has been used for decades. Chromate conversion coating prevents oxidation (rusting) on metals. It can be used as a base for painting in some cases. When chromate conversion coating is applied, its purpose is to passivate metal substrate, preventing oxygen in air to corrode the metal surface. Chromate conversion coating is used on metals such as aluminum and zinc, and to a lesser extent copper, cadmium, silver, tin, and other metals and their alloys. The major concern nowadays with chromate conversion coating is its toxicity.
Hexavalent chrome is toxic and causes cancer in people. Trivalent chrome, the less-toxic sister of hexavalent chrome, scientifically has not been shown to cause cancer in humans, but is likely only a matter of time before it is shown. Hexavalent chrome is toxic to aquatic life and virtually all mammals including some insects. Some governments have banned its use or have pending legislation to ban its use. The question facing industry today is what alternative is available that performs as well as chromate conversion coating and is non-toxic.
Vanchem’s GREENCOAT RF is that product. GREENCOAT RF is a non-chrome organic reactive film that passivates the metal surface as chromate conversion coating does, but without toxic effects. Vanchem formulated GREENCOAT RF as an excellent base for paint for those industries interested in painting manufactured metal products.
Not only does our GREENCOAT RF technology replace chromate conversion coating, it can also replace iron phosphate as an environmentally friendly alternative because it contains no phosphates. Phosphates are not toxic. However, governments worldwide regulate the level of phosphates that industry discharges to sewer because phosphates are a high nutrient source for bacteria growth (See our article Waste Water Pretreatment for more information). Once bacteria grows in water sources where aquatic life thrives, like rivers, streams, and lakes, bacteria depletes oxygen content to a point that results in aquatic life dying. This is obviously undesirable. Bacteria can also grow to levels that become toxic to humans. If there are no nutrient sources, bacteria will not grow. This is why phosphated cleaners are regulated and phosphates that come from iron and zinc phosphating are regulated.
As an aside, industry uses this phenomenon to treat sewage. Activated sludge (living bacteria colonies) consumes nutrients in sewage water. Your Municipal wastewater treatment facility then use chlorine to kill remaining bacteria colonies before the water is sent back to its source, such as rivers, lakes, and oceans. Remember, these water sources are where we get our drinking water.
Let Vanchem help your facility become chrome-free and use our alternative to chromate conversion coating technology. Call us and ask about our GREENCOAT RF and other technologies designed to replace chromate conversion coating.
For more information about Vanchem’s environmentally friendly products, contact us at our corporate headquarters in Burlington Ontario.Articles