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Nickel plating failing 96 hour salt spray test
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I am having a problem with obtaining a nickel plating thickness of 15 microns on a security collar for a lock. (3 cm diameter, 1 cm wide and 0.3 cm thick) I have been told by a plating shop that it is impossible to increase the thickness beyond 8 microns because the base metal is free cast iron. I do not believe this to be true, am I wrong? The part is only lasting 48 hour in a salt spray test and I am aiming for it to last 96 hours. Could the problem be relating to the pre-plating cleaning?
Thanks,
Paul
Paul O'Driscoll- Taipei, Taiwan
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Please try with following combination
Base material+Copper (4 to 5 microns)+ Ni (15 microns)+chrome flash.
We have carried the salt spray test on the base material steel with combination and our part is passed for 96 hours.
Best of luck.
bahadur singh- Udaipur, India
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I don't think there's a problem if you can cyanide copper plate first to a thickness of 15 microns before nickel plating. It will also give you better corrosion resistance.
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Khozema Vahanwala Saify Ind  Bangalore, Karnataka, India |
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Please try the following :
- Cleaning
- Cyanide Cu Strike
- Semi-bright Nickel (60% of total Ni)
- Bright Nickel (40% of total Ni)
- Chrome
Critical is the duplex nickel with a potential difference of approx. 100mV.
Jason Wu- Hong Kong SAR
March 20, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
nickel chrome plated parts are failing salt spray test.
sir we are doing nickel chrome plated 12 microns & chrome 3 min,
but in salt spray it is staying only 24 hrs but customer needs 75 hrs what should I do?
plz help me
plating shop - Bangalore, Karnataka, India
March 22, 2011
Hi, Ahmed.
We've appended your inquiry to a thread that may help answer it (see also letter 53155). It strikes me that the fact that you are able to get 24 hours from your current process is good, and serves as evidence that your process is under control -- but that a single layer of nickel 12 microns thick is not up to the task and you must use a copper undercoat, or duplex nickel, or substantially thicker nickel. Good luck.
Regards,
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
March 22, 2011
3 min in a chrome tank is barely enough to get color. You will get zero corrosion resistance from that amount. So, You are looking at nickel having to do the job and 12 micron will rarely do the job, even with electroless nickel.
James Watts- Navarre, Florida