plating, anodizing, & finishing Q&As since 1989
Can brass be made magnetic via plating?
We barrel plate both steel and brass hardware with 6 microns of cyanide copper and 6 microns of nickel. Our customer has begun complaining that the items are magnetic--even the brass hardware! In 50 years of plating experience I have never heard of such a thing. Is it possible? Any response appreciated.S.C. [last name deleted for privacy by Editor]
Steel hardware can be inadvertently magnetized in many manufacturing operations. I have seen automatic plating lines which incorporated a degaussing device between the final rinse and the dryer. But I would be amazed that 6 microns of accidentally magnetized nickel could generate a problematic magnetic force and, to the best of my knowledge, copper and brass (copper-zinc) cannot be magnetized at all. Keep us posted!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Nickel is paramagnetic. Some forms of nickel can be magnetized and other forms can not. Confused? Some electroless nickel can be magnetized and others can not. You have to look at the precise way that it was plated to be able to answer the question.
There are a number of ways that you might not suspect that can magnetize metal. A thin coating of nickel is not going to be a very strong magnet, but for a computer or similar, it is a very very tiny amount of magnetism required to work or fail.James Watts
- Navarre, Florida
[I realize that this question was posted back in 2000, but you did ask to keep posted; I am writing this in January of 2005. ]
According to the chemical-rules for exhibiting Magnetism, a SINGLE atom of Copper qualifies as being Magnetic. However, when dealing with a large sample of Copper, the electrons re-distribute so-as-to defeat the possibility of exhibiting Magnetism.
This topic recently caught my interest because I had just received some all-brass pins [the kind used in the garment industry] that exhibited the property of being magnetic. [Maybe these pins now double-as Security Tags for catching shoplifters.]John E. Berry, Jr.
Electronic Component designer and fabricator - Binghamton, New York
Ed. note: Don't worry too much about the age of the posting, John. There are a hundred readers for each poster, so this forum is a lot like 'Dear Abby' or 'Hints from Heloise', directed as much at readers as at the original inquirer :-)
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