Zinc Chromate Finish

Chromate conversion is a type of conversion coating used to passivate a number of alloys.

Zinc chromate finish.

Zinc trivalent chromate plating. Wash primers especially the acid activated type are considered pretreatments and should only be applied directly to bare metal. 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. P 1265 the coating serves as a corrosion inhibitor as a primer to improve the adherence of paints and adhesives as a decorative finish or to preserve electrical conductivity.

Degrease the zinc chromate to remove oily soils and paint over it. Glmf still processes many parts with hexavalent chromium but we have seen a push to use trivalent passivates on zinc plated parts. 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. The yellow chromate is a yellow bronze iridescent finish on plated cadmium and zinc.

The zinc chromate pretreatment is a perfect pre paint treatment for aluminum. Blue chromate our blue chromate concentrate produces a true blue conversion coating on zinc plated items. Great lakes metal finishing is experienced in effectively using both trivalent chromate otherwise known as trivalent passivation and hexavalent chromium. To improve those older zinc pot metal castings plate with a fresh zinc plate before chromating.

Zinc chromate is a corrosion resistant agent that is added to certain coatings. 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 is a top coat that is put on zinc plated items to deter the zinc from white rusting. Most commonly steel aluminum zinc cadmium copper silver magnesium and tin alloys benefit from this process.

It is primarily used as a corrosion inhibitor paint or other finish primer decorative finish or to retain electrical conductivity. Liquid concentrate is used at 0 5 to 3 by volume in water at 65 to 90 f. The zinc the chromate react to form the new colors. 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.

It is used industrially in chromate conversion coatings having been developed by the ford motor company in the 1920s.