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Alternative to Chromate Conversion Coating
Can you suggest any alternative to chromate conversion coatings?Rout
- Jamshedpur, Jharkhand, India
There are some options out there. If you are just trying to get away from hexavalent chrome, you can substitute a trivalent chrome. A tri-chrome system may require an additional topcoat/sealer in order to get sufficient corrosion resistance.
It is harder to get away from all chrome conversion coatings. Either price, quality, or both suffer. You may look into platings that do not require passivation. One of them, I believe, is tin-zinc. I also heard something about zinc-manganese and zinc-carbon, but I don't really have any info about those platings.
You might also want to look at changing your material to plastic, aluminum, or stainless steel. You might want to look at completely different finishes like e-coat, powder coat, paint, PVD, etc..
Rochester Hills, Michigan
tin/zinc might not need a chromate finish, but it certainly benefits from it. There is a report from NCMS, number 17-0403 "Alternatives to Chromium for Metal Finishing" it sounds like it could be what your looking for. I've yet to read it myself. I hope this is helpful. IanIan Brooke
university - Glasgow, Scotland