Letter 12022

Electroless Nickel Plate Residue Problems 

Hi,

I'm the Assistant Production Manager in a small Scottish engineering company. At present we turn and grind mainly mild steel shafts which are then electroless nickel plated. The thickness of the plate is normally between 0-20 microns dependent on the customer requirements. We present the shafts to the solutions in stainless steel jigs (nominally 250 shafts per jig) and dry in a non circulating oven. The problem is that a high percentage of the shafts end up with jig marks at the contact points with the shafts or water marks along the diameter of the shaft. It is the company's belief that this is mainly due to the oven not drying the residue off the shafts quickly enough.

Can anyone confirm or rebuke the consensus of opinion here?

Eddie Moore
- Paisley, Renfrewshire, Scotland

The old joke goes: "How many computer programmers does it take to change a light bulb?" "None, they adjust the software". The silly part of course is that you actually should fix a light bulb by fixing the lightbulb not something else.

The applicability to your question is that if you have objectionable jig marks, what you will need to do is fix the jigging method, not the electroless plating solution or the oven. As for the water marks, usually they are not actually caused by water but by the dissolved salts in the water. It is usually necessary to rinse in de-ionized water, or to use some drying aid like alcohol, solvent, etc.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

These jig marks, are they rust colored? Are the water marks white hard-water deposits? Have you tried clean rinsewater? Have you tried to blow the parts dry using clean compressed air, after a hot deionized dip?

Tom Pullizzi Platronica.com Falls Township, PA

But of course! There are residues that are simply not dryable (they are as dry as they can be). Also, if you contact any surface that is to be immersed for plating or anything else, you are impeding the liquid to get to that point.

Guillermo Marrufo
Monterrey, NL, Mexico

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