Metal finishing Q&As since 1989

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Cleaning/activation of aluminum/titanium bimetal

2005

I have a requirement to Ni and Au plate a titaniumCP/aluminum4047 bimetal component. I know how to clean/activate/post process the Ti to get the plating adhered, and I know how to clean/activate/post process the aluminum for successful plating. The problem is putting them both together.

I belive that a NaOH clean followed by an Al2O3 abrasion will activate the Ti. If I keep the part from oxiding (such as placing it in acetone [on eBay or Amazon] ) I can then move forward with the Al clean and activation. I believe that the NaOH does a fair job of cleaning the Al, but I'm afraid to put the Ti into Nitric Bifluoride and zincate, which is the typical prep for Ni plating on Al.

Question: what effect will the Nitric Bifluoride and zincate have on the Ti? Would a fluoboric acid bath do the job of aluminum clean/activation instead? are there any other suggestions for this crazy process?

Jim Petri
SRI Hermetics - Melbourne, Florida, USA

How about using a solution of 30mls/L HF and 30mls/L H2SO4 as an etch which will work on both the Al and Ti. I can't see a problem using a zincate for an ENP coating however you may need to give the EN a kick start with a power pack.

Chris Matthews
- East Sussex, England
2005