Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Zinc plating on copper
Q. Can zinc plating be done on copper. We have a requirement of copper tubes which should be zinc plated? Sounds strange can you help me in deciding the correct processing parameters?
Satish Deshpande- Mumbai, Maharashtra, India
A. Why not? If you don't require internal plating, it would be a good idea to plug up the ends with rubber to prevent dissolution of the copper in whatever type of plating solution you use.
Regards,
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
A. Technically, zinc plating on copper is not a problem. However, diffusion of the zinc into the copper will occur. If the zinc plating is not of sufficient thickness it may seem to disappear! Obviously, the resultant material at the interface of the zinc and copper and after migration will be brass. The big question is why do they want zinc?
Gene Packmanprocess supplier - Great Neck, New York
Q. What if I wanted to put trivalent chromate over the Zn plated copper? We have a copper plated pin that gets brazed into another part. The assembly then gets Zinc + chromate for corrosion resistance. The copper seems to be reducing the effectiveness of the chromate and we get white dust (Zn oxide?) and some red rust when we salt spray test.
Grant
- Westfield, Indiana, USA
February 28, 2011
A. Hi, Grant.
It is true that the galvanic couple between zinc and copper is stronger than between zinc and steel, so that once the copper is exposed the zinc will corrode faster. But perhaps a heavier layer of zinc, such that there is no porosity, will solve the problem.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2, 2011
Why does zinc plating of copper soften the copper?
Q. I want to ask about Zinc electroplating of Copper, using ZnSO4, and H2SO4 as additive agents. Why did copper hardness after electroplating drop? Before this experiment, the hardness reading was 20 above. Anyone can help?
hiroqas piya- Kangar, Perlis, Malaysia
September 20, 2015
A. I seriously doubt if the zinc plating softened the copper. I think that the hardness testing is the problem. The zinc is very probably softer than the parent copper and you are reading a value of both.
If in doubt, sand the zinc off of a part and take another reading of the copper. On the same part as the before plating.
- Navarre, Florida
September 24, 2015
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