Technical help for Nickel Barrel Electroplating

Dear Sir/Madam,
Can any body help us in advising how to nickel electroplate, our components which are small & precision Tungsten Contact Rivets (size: About 4 mm in Dia x 4 mm length), Production Parts ( bulk quantity), Plating Thickness Desired: 1~ 2 micron, Finish: Preferably Dull, using Electrolytic Nickel Barrel route.

Presently, we are facing the problem of poor adhesion of nickel on tungsten base metal ( i.e peel-off). Up to 0.5~0.6 micron is achieved, but after that adhesion becomes difficult and plating layer peels-off.

with warm regards

Vikas,
I had a customer some years back that would use a reverse current (anodic) sulfuric acid dip after soak and electroclean. I don't remember the H2S04 concentration though. This would etch the surface slightly, then went into a woods nickel strike, followed by nickel plate. I believe he was using a nickel sulphamate bath. The owner of the company told me the process worked well. Good luck to you.

Dear Mr. Mark Baker,
Many thanks for your kind advise dt. 10-Oct-09. We shall definitely try your idea in our job, and shall let you know the results.

thanks once again and with warm personal regards - Vikas Jain