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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Cracking of plated nickel silver parts during forming
Q. Help!
I am plating nickel and gold on a nickel silver alloy 770 1/2 hard part. The parts are acid etched from sheets of the base metal. Before they are plated the are etched in an acid solution to activate the surface and remove any residue that may be present on the surface. After the parts are acid etched they are rinsed in de-ionized water and racked. The next step is to immerse them in a 20% sulfuric acid solution. They are then plated with 50 to 100 micro inches of nickel, rinsed and plated with 30 micro inches of gold. We have been running these parts for about 10 months, in the past 2 weeks I am experiencing a fracturing of the deposit and the base metal when the parts are formed. I formed parts in the raw state (not etched or plated) and the base metal seems to bend fine.
Someone mentioned to me it could be a result of embrittlement from the nickel plating. Has anyone ever seen this problem? Does anyone have any suggestions on a cure for this condition?
Thank You,
Alan E. Ashton- Painesville, Ohio, U.S.A.
2001
A. What type of Nickel Plating bath and condition are you using? How do you control your bath? Do you check stress in the deposit? Do cross section of defect and investigate where there is adhesion problem.
Payal Mag- Charlotte, North Carolina
2001
A. I have worked in the aircraft manufacturing industry, and they have always required a baking process after any contact with an acid (plating or etching) to relieve the hydrogen embrittlement.
Joe Garvas- Mentor, Onio, USA
2001
A. Try baking your parts at 400 Degree F for 4 hours after rinse.
J F Mathews- Clearfield, Utah , USA
2002
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