Neodimium magnets
Neodimium magnets
(OP)
We have a couple of our neodimium magnets plated in Nickel. ASTMB633
We need a test for our receiving inspection other than the std "peel test" to test for adhesion, which does not appear to catch all the discrepant parts. Any ideas are welcome.
Regards
We need a test for our receiving inspection other than the std "peel test" to test for adhesion, which does not appear to catch all the discrepant parts. Any ideas are welcome.
Regards





RE: Neodimium magnets
TTFN
RE: Neodimium magnets
we have a test where we score the sample part with a knife and press some sticky-tape on there and then we rip the tape off...fairly basic really, but it does identify some bad batches.
Later on,in service, we see peeling occuring, that was not apparent at receiving inspection, even with this test.
regards
RE: Neodimium magnets
I've found that nickel, or any metallic plating on Neo magnets, does not have high adhesion strength. Once the surface is scored it tends to peel off fairly easily. I have tried to find a measurement of the adhesion strength, to no avail.
RE: Neodimium magnets
RE: Neodimium magnets
Additionally, the Ni plating is quite tricky. Many plating houses like "shiny" Ni, but that usually implies a harder Ni that tends to crack when the magnet is subjected to temp cycles. You should check to see if there is any hardness variation in the plating.
TTFN
RE: Neodimium magnets
We did a lot of Ni work. Ended up with a copper flash and then electroless Ni, with very low P.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Neodimium magnets
However, it has a low coefficient of friction so it can be a challenge to bond a parylene coated magnet into an assembly.
RE: Neodimium magnets
Just had a thought: Are you doing your peel test on the parts while they are magnetized? If so, it's possible that the magnetization is helping the otherwise discrepant parts hold onto the plating a bit more strongly (nickel is ferromagnetic and thus attracted by a magnet). It might help improve accuracy to work on parts in the non-magnetized condition.