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Timeline of change from hexavalent to trivalent chrome  

September 16, 2008

Can some one tell me when did the change from Hexavalent to Trivalent chrome happened in the US.

Did automotive / truck industry use hexavalent chrome for exhaust stack prior to 2000.
Which year did majority of the exhaust chrome plating suppliers switch to Trivalent from Hexavalent. Is there a US govt. mandated date like EPA 2010 emissions timeline.

Thank you in advance for the response.

Deepak Adharapurapu
Customer - Madison, WI, USA

Hi, Deepak. To my knowledge there are no U.S. laws governing this.

European RoHS, WEE and other standards drove a transition from hexavalent to trivalent chromate conversion coatings. This has to do with the unacceptability of leaving hexavalent chromate conversion coatings on the surface of parts. It does not dictate whether hexavalent or trivalent processes be used for the process as long as there is no hexavalent chromate on the parts.

But chrome plating baths are different than chromate conversion coating baths; they deposit metallic chrome onto articles and leave neither trivalent nor hexavalent chrome on the parts. So the question of hex vs. tri has little to do with chrome plated parts, only chromate conversion coatings.

To my knowledge, most automotive chrome plating specs still require hexavalent chrome plating. Good luck.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey