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  for Metal Finishing since 1989
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Ozone resistant black finish on aluminum

Can anyone suggest a black coating for aluminum extrusion that would resist fading after exposure to high ozone. We currently use a black sulfuric acid and after time the dye used in anodize fades and we loose the black color. The high ozone is being generated in a charging corona environment. We need the antireflection properties to remain intact.

Kristen Gratalo
Hewlett Packard - Boise, Idaho
2006

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Even a well sealed anodize is not going to stand up to what you are using it for.
Consider hard anodizing, the choice of alloy will give a very dark grey finish. Dye helps, but it will not survive forever, sealed or unsealed.
2nd, consider using a two step architecture anodizing. Pure black is not an option, but some very dark colors are.
Black nickel is variable in color and scratches easily, where black chromium works better, but costs more.
Lots of options, but no perfect answer.

James Watts
- Navarre, Florida
2006