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Plating on Zamak #2 vs. #3

Are there any special considerations to be concerned with when plating Cu/Ni/Cr on Zamak#2 (as opposed to Zamak #3)? We have a very established captive plating process for plating decorative finishes on zinc die castings, however we have always used Zamak 3 as the substrate. Design Engineering now wants to use Zamak 2 for some new castings due to increased strength properties. Any Concerns?

Thank You.

Jim Sweney
Plating Engineer - Indianapolis, Indiana
January 7, 2011

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Dear Jim
as you know Zamak 4 it is the best zinc alloy for nickel electroplating
if you try to use Zamak 2 you need to make chemical analysis for it and check Cu . Fe , Si, etc compare it to Zamak 4
I think Zamak 2 will need special conditions and will give you many electroplating defects
best regards

Ali Gomaa Farid
metal finishing expert - Egypt
February 17, 2011

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March 2, 2011

Thank you for your comments. Zamak 4 is only available in Asia, that I am aware of. Zamak 3 is the standard zinc for plating in North America.

The Zamak #2 has about 3% Cu added to it for strength. That is the difference between #2 and #3(no Cu).

I do not know why the additional Cu would cause problems with the plating (Cu/Ni/Cr), but I was hoping someone would have some experience here.

James Sweney
- Indianapolis, Indiana