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 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 chromating process?
Chromating is the conversion coating process of depositing an oxide layer over a metal surface to enable the metal to react with the oxide layer. This forms a layer of passivated metal chromate on the surface.
What is trivalent plating?
Trivalent chromium plating, also known as tri-chrome, Cr3+, and chrome (III) plating, uses chromium sulfate or chromium chloride as the main ingredient. Trivalent chromium plating is an alternative to hexavalent chromium in certain applications and thicknesses (e.g. decorative plating).
What is 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 color is trivalent chromium?
Trivalent chromium electroplating processes have been commercially available since the mid 1970s. Processes are available today offering deposits with colors varying from gray-black to almost the blue- white appearance of hexavalent chromium.
What is trivalent passivation?
Trivalent chromium passivation is used after zinc plating for enhancing corrosion resistance of parts. These metal ions deposit into the passivation as hydroxides, and the larger the quantity in this layer the more the layer contracts by heating, meaning the newer the solution the less the layer contracts.
Is trivalent chromate conductive?
Trivalent chromate deposits are electrically non-conductive (unless applied over a zinc alloy or a metallic substrate).
Is trivalent chromium conductive?
This trivalent chromate chem. film is harder than conventional trivalent chromate. It is electrically conductive (LER – low electrical resistance) and it meets or exceeds ASTM D2559-9, MIL-DTL-5541 F and MIL-DTL-81706 for electrical resistance.
What is trivalent chromium used for?
Trivalent chromium is another method of decorative chrome plating, and is considered the environmentally friendly alternative to hexavalent chromium, with many of the same characteristics; just like hexavalent chrome finishes, trivalent chrome finishes provide scratch and corrosion resistance and are available in a …
What can trivalent chromate conversion coating be used for?
The trivalent chromate conversion coating process provides outstanding corrosion resistance and conductivity, without any measurable buildup. This low-cost process is primarily used as a corrosion inhibitor and as a primer for paint, lacquer, or rubber bonding.
When to use a trivalent passivate / chromate?
Trivalent Passivate/Chromate FAQ. 1) What are passivates/chromates? Passivates/Chromates are used to coat metal parts in order to provide a longer life for the part. It is commonly used on zinc-plated parts in order to provide protection from corrosion such as white rust or red rust.
What’s the difference between hexavalent and trivalent chromate switches?
The switches using the new Trivalent conversion appear to have a higher resistivity than the old yellow Hexavalent conversion without the Zinc preplate. Is there a difference in the conductivity of the Hexavalent chromate vs. the Trivalent Chromate?
What’s the difference between thick film and trivalent chromates?
Many of the new trivalent chromates employ “sealers” or “topcoats”, although our understanding is that the “thick film” trivalent chromates do not. Some cautions that are in order when reading these dialogs are: – trivalent chromates are highly proprietary, and what may be said of one may not hold for all.
