What is a trivalent passivate?

Trivalent chromium passivation is used after zinc plating for enhancing corrosion resistance of parts. In the passivating process, the amount of dissolved metal ions (for example zinc and iron) in the passivation solution increases the longer the solution is used.

What is the difference between Cr3 and Cr6 plating?

Cr3 is an essential micronutrient and has low toxicity. Cr6 is more toxic and is known to cause cancer when inhaled.

What is trivalent coating?

Trivalent conversion coatings is used on metals such as aluminum and zinc, and to a lesser extent copper, cadmium, silver, tin, and other metals and their alloys. Trivalent conversion coatings are used to passivate aluminum and as a sealer on metal parts after an iron or zinc phosphate metal finishing process.

What is difference between trivalent and hexavalent?

Hexavalent chromium itself is a hazardous substance and carcinogen and is heavily regulated by the EPA. Trivalent chromium plating uses chromium sulfate or chromium chloride as its main ingredient, instead of chromium trioxide; making trivalent chromium less toxic than hexavalent chromium.

What is trivalent chromate?

Black Trivalent Chromate is the top coat applied after Zinc-Nickel plating to provide added corrosion resistance and a black color to the part. Black chromate finishes are used in a variety of industries including automotive, military, oil and gas, and more.

What is Cr3 coating?

Alternative coatings have been developed using Trivalent Chromium (Cr3), which does not have the same toxic characteristics. Thin film systems provide a decorative and basic corrosion protection coating. Thick film systems provide much higher corrosion protection to meet automotive specifications.

What is Cr3 plating?

Zinc coating passivations Thin-layer passivation Cr3+: (blue) 0.08-0.1 µm on zinc layer. It is used for parts that are less exposed to corrosion. Thick-layer passivation Cr3+: (slightly iridescent appearance) 0.2-0.3 µm on zinc layer. Higher corrosion resistance comparable to yellow chromate.

What’s the difference between hexavalent and trivalent?

What is chromium trivalent?

Chromium occurs in the environment primarily in two valence states, trivalent chromium (Cr III) and hexavalent chromium (Cr VI). Exposure may occur from natural or industrial sources of chromium. Chromium (III) is an essential element in humans. The body can detoxify some amount of chromium (VI) to chromium (III).