Summary for nickel chrome plating rusts Discussion
Nickel chrome plating rusts in 8 hours is the problem Dhanabal M. reports on MS parts plated with about 22 microns of nickel and 0.3 chrome, yet showing a rust line across the surface. Popatbhai B. Patel says those thicknesses sound like good decorative nickel-chrome, so rusting should not normally happen. He asks for photos to better identify the defect and suggests the line may be porosity from hydrogen bubbles caused by high surface tension in the nickel, possibly worsened by poor air agitation. He recommends removing the rust and checking for a line of bright hemispherical gas pits. If that is not the cause, he advises testing with a pumice scrub before plating to rule out inadequate cleaning. The thread emphasizes that the visible line pattern is important to diagnosing whether the issue is porosity, cleaning, or another process problem.
Q. I’m doing nickel chrome decorative plating on MS material (Semi Bright, Bright, Mps, chrome activation followed by chrome plating).
I’m getting thickness around 22 microns nickel, and 0.3 chrome … still we are observing rust in 8 hours; and the rusted area looks like a line all over the surface.
Dhanabal M
– India, Chennai.
December 13, 2024
A. Hi Dhanabal,
Those specs describe good quality nickel-chrome plating so you should not be having any rusting problem. Please send photos to finishingdotcompublic@gmail.com for posting here so we can better understand what you mean by “like a line all over the surface”.
Is there a chance that this is a line of porosity due to hydrogen bubbles from too high surface tension in the nickel, combined perhaps with lack of air agitation
⇦ huh?
in that area? Remove the rust and look for a line of bright hemispherical gas pits.
If not that, then scrub some sample parts with a pumice solution before putting them into the plating line, as a test against inadequate cleaning. But *good* photos would probably be a big help.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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A. Rust after nickel-chrome plate, analyze step test – bright Ni, bright nickel and microporous nickel, check powder concentration in microporous nickel tank.
Need nickel thickness 1.5 mil.
Popatbhai B. Patel
electroplating consultant – Roseville, Michigan