This is considered a bronze alloy and I don't have an answer for you but I do know where two spots where you may be able to get a proper answer.
The first is the Copper Development Association Inc. at www.copper.org/ Go to "Resources" / "Questions?". Fill out the form and state your question there.
Please let us know how you make out.
Regards Peter J. Stewart-Hay Principal Stewart-Hay Associates www.Stewart-Hay.com 519 641- 3212
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