Metal finishing Q&As since 1989

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Blackening process for Al metal? Methods to improve resin bonding with Al?

Is there a process by which to blacken aluminum metal? And would this blackening process provide an increase in surface area that could promote bonding with epoxy resins. I am a PCB wet process supplier and I have been asked if our black oxide process will work on aluminum. I am not exactly sure why this person wants to turn the aluminum black at this point but I am assuming that because our black oxide process is used in bonding copper metal to epoxy resins that they want to do the same. I do not think our process will work with aluminum but I will try it anyway. Any insight would be appreciated.

Thanks!

Scott Campbell
- Tempe, Arizona, USA
 

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You can anodize aluminum (preferentially growing the surface Al oxide layer). Anodize is porous and therefore should provide a good adhesion layer. The anodize layer can be colored by using dye which seeps into the pores. The pores are then sealed. Contact an anodizer regarding processing of your specific Al alloy.

Good luck with the application!

Gus Vallejo
AlumiPlate, Inc. - Minneapolis, Minnesota
 

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Any anodizing process will improve adhesive bonding. Hard anodizing is grey to black without need for dyes.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey