Zinc Chromate Finish
Blue chromate our blue chromate concentrate produces a true blue conversion coating on zinc plated items.
Zinc chromate finish. Liquid concentrate is used at 0 5 to 3 by volume in water at 65 to 90 f. Chromate conversion coating or alodine coating is a type of conversion coating used to passivate steel aluminium zinc cadmium copper silver titanium magnesium and tin alloys. Zinc trivalent chromate plating. The zinc the chromate react to form the new colors.
There is no real difference between a zinc finish and a zinc chromate finish because although there are now some chromate free topcoats zinc plating is always top coated. Wash primers especially the acid activated type are considered pretreatments and should only be applied directly to bare metal. Back in the 1940s as well as in the paint industry of today the term zinc chromate does not refer to a paint color but rather a protective coating. Chromate conversion is a type of conversion coating used to passivate a number of alloys.
To improve those older zinc pot metal castings plate with a fresh zinc plate before chromating. The zinc chromate pretreatment is a perfect pre paint treatment for aluminum. Degrease the zinc chromate to remove oily soils and paint over it. Chromate is a top coat that is put on zinc plated items to deter the zinc from white rusting.
There s no need for a wash primer. The yellow chromate is a yellow bronze iridescent finish on plated cadmium and zinc. It is primarily used as a corrosion inhibitor paint or other finish primer decorative finish or to retain electrical conductivity. Zinc chromate zn cr o 4 is a chemical compound containing the chromate anion appearing as odorless yellow powder or yellow green crystals but when used for coatings pigments are often added.
Zinc chromate is a corrosion resistant agent that is added to certain coatings. Glmf still processes many parts with hexavalent chromium but we have seen a push to use trivalent passivates on zinc plated parts. It is a single dip blue trivalent chromate that offers high salt spray resistance for up to 130 hours to white rust corrosion and. It is used industrially in chromate conversion coatings having been developed by the ford motor company in the 1920s.
Most commonly steel aluminum zinc cadmium copper silver magnesium and tin alloys benefit from this process.