Summary for hexavalent chromium on finished products Discussion
Hexavalent chromium on finished products is the central concern in this thread: James Haney asks whether any Cr6 can remain on a plated, rinsed, dried, and finished machine component sold worldwide, especially since Europe will not accept the part if any remains. He notes the belief that Cr6 converts to Cr3 by the end of the process and asks what would have to go wrong for Cr6 to persist and whether the issue is significant. The excerpt shown includes the question only, so no technical answer is provided in the source text. As a result, the page mainly frames the compliance and process-control concern rather than resolving it. The practical takeaway from the visible content is that the risk is being treated as a regulatory and finishing-process question, but the thread excerpt does not supply a documented conclusion or expert recommendation.
Q. The question presented to me was, ” Is there any hexavalent chromium on a component after it is plated, rinsed, dried, and finished?” The part is a machine component sold around the world. The machine cannot be sold in Europe if any Cr6 remains on the component. Supposedly, the Cr6 becomes Cr after the process is complete and we are confident that it does. What would have to go wrong for the Cr6 to stay, and how likely is it to happen?
Should this even be an issue we have to worry about?
Thanks Again
James Haney
Enviromental Engineer – Cleveland, OH, US
2005
 | A. Just to clarify – are you talking about chrome plating or zinc plating with a chromate topcoat? If you’re talking about chrome plating, the only possible way hex-chrome would be involved at the end was if chemical was entrapped If you’re talking about zinc plating with a chomate topcoat, then hex-chrome is involved unless you specify otherwise. To avoid it just make sure that you specify a hex-free chromate. Good luck. Jim Gorsich 2005 A. RoHS questions from an Environmental Engineer…this has to be a first! At least you have some knowledge of chemistry and are likely to grasp the concept! However, you didn’t tell us what plating you’re dealing with: is it zinc with a chromate post treatment? or chrome plating? or black chrome plating? If it’s zinc or cadmium it’s likely to contain hexavalent chrome. If it’s chrome plating including either decorative nickel chrome or hard engineering chrome, it should be chromium metal with a valence of zero – that is non-hexavalent! Any residual hex chrome that remains could be construed as a contaminant and not intensional, thus is permissible up to the 1,000 ppm threshold. Black chrome plating is another story and as far as my firm has tested, it contains hex chrome as it deposits chromium trioxide which means the chromium is hexavalent! It’s encouraging that someone with an engineering background is finally asking the right questions – congrats to you!
2005 |
