Metal finishing Q&As since 1989

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Chrome-Free Passivation

Hi everybody,

I am sure you heard this question asked many times: is there a chrome VI-free yellow passivation for zinc available? I believe there was one advertised but I have not been able to find anything about it. If anyone can help I would appreciate it. Best regards Trudy

Trudy Hattingh
- Durban, South Africa
2000

You have not mentioned the reason why yellow passivation is necessary. If it is just for color, then there are one group of alternatives. If it is corrosion protection that opens up a different group of questions. If it is for protection and color products are available from several suppliers in Europe and more recently the U.S. I do not know if any of these are being marketed in your country. Most have been developed for new automotive specifications. If you could elaborate on your question I will try to give you a more definitive answer.

Gene Packman
process supplier - Great Neck, New York
2000

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Hi Gene Packam,

Thank you for your interest in my problem. The main reason for yellow passivation is corrosion protection. There are no zinc alloys being plated yet in this country, therefore we are looking to the passivation to give maximum protection. We have chrome VI-free blue passivation, but although we have access to all the major supply houses, non is marketing a chrome VI-free yellow passivation. Best regards Trudy Hattingh

Trudy Hattingh
- Durban, South Africa
2000

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I am in the automotive industry also. So far the only trivalent chrome passivate that we have seen in metallic grey with a faint blue hue. We are going to be investigating a possible black trivalent system. I would definitely be interested if someone in the US has a trivalent yellow because our customers are used to yellow. We struggle with the new specifications because we have some of the highest corrosion protection specs in automotive (700, 1200 hours of salt spray). Please feel free to contact me privately. I do not want this discussion thread to become a chemical vendor ad.

Tim Neveau
Rochester Hills, Michigan
2000