Chromate conversion coating is a type of conversion coating used to passivate aluminum, zinc, cadmium, copper, silver, magnesium, and tin alloys. It is primarily used as a corrosion inhibitor, primer, decorative finish, or to retain electrical conductivity. The process is named after the chromate found in the chromic acid used in the bath, more commonly known as hexavalent chromium. This type of bath is still the most widely used, however hexavalent chromium is toxic and, thus, highly regulated, so new non-hexavalent chromium based processes are becoming commercially available. One alternative contains trivalent chromium. The RoHS (Restriction of Hazardous Substances) Directive is commonly referenced when it comes to eliminating hexavalent chromium.
Chromate conversion coatings are common on everyday items such as hardware and tools and usually have a distinctive yellow color.
Read more about Chromate Conversion Coating: Composition
Famous quotes containing the words conversion and/or coating:
“The conversion of a savage to Christianity is the conversion of Christianity to savagery.”
—George Bernard Shaw (1856–1950)
“The world is eaten up by boredom.... You can’t see it all at once. It is like dust. You go about and never notice, you breathe it in, you eat and drink it. It is sifted so fine, it doesn’t even grit on your teeth. But stand still for an instant and there it is, coating your face and hands. To shake off this drizzle of ashes you must be for ever on the go. And so people are always “on the go.””
—Georges Bernanos (1888–1948)