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Small water mark after plating

I am an engineer of an assembly device. I have a component which is a steel contact plate for small consumer battery. This metal contact is nickel plated. My customer complains that they have intermittent contact with the battery and suspects it is the water mark on the plating that causes it. I thought water marks is common in plating as long as it is not too obvious and it should not have any functional effect on the plating quality. Can someone with experience on water marks in plating share his view with me ? Thanks.

John Ow
product engineer - Singapore
March 23, 2009

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March 28, 2009

You didn't tell how you dry the contacts and how you plate them(by tromel?)
if you use a centrifugal for drying you can open in the middle of the process and add clean deionized water; this should solve the problem

Ricardo Burstein
Bnei Berak, Israel

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Hi John,

Watermark is one of the common defect in plating. Normally depending on the application, some small water mark can be neglected. However, end-user will always blame on thing that is not suppose to be there in the first place.

For a functional plating, i.e for your case a contact point, the water mark will normally reduce the efficiency of the conductivity. Therefore, it is necessary to avoid the water mark from occurring.

The other questions is whether the thing you see is water mark or not. Sometime it could be plating defect. To determine it, normally I will use IPA to wipe clean the area and if the mark disappear, then it is just water mark.

To improve the water mark situation, it is best to have the last water rinse to be very clean follow by a drying process.

Good Luck.

Robin Chua
Freelance Advisor - Singapore
April 5, 2009