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What is the normal ASF for sulfamate nickel

2007

What is the normal ASF for sulfamate nickel. I'm trying to plate a small round ring part that has many low current areas but I need to get this plating as even as possible. .0005 per side.
I'm currently using just a simple hook rack. No tension at all.

What can be done to help throw into my low current areas more effectively. Right now I go 20 ASF at 30 min and get an uneven coating. .0001 at the rack area.

Mark Randall
- AVALON, GA, USA

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Gravity hooks are not necessarily "wrong", Mark. But if you are looking for even thickness, you can minimize not only rack marks but "shading" from these cup hooks by using a purpose designed rack with tiny spring tips.

There really isn't a "normal" ASF, Mark. 20 ASF is fine, but 40-50 is probably possible with reasonable agitation, and far greater than that with high pressure impingement. But on the other end of the scale I have seen articles electroformed in sulphamate nickel as low as 1 ASF.

Personally, I'd make well designed racks issue number 1.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

The best way to get plating in the recesses with a sulfamate bath is to use strong agitation. This will require a better rack. mask off the rack as close to the point of contact as you can to reduce the robber effect on the part. The spline of the rack should be at least an inch from the part or you will get shielding on that side. I would run the temperature around 130 -140F, bu no higher. 20 ASF should give you the half a thou per side in 30 min, but that is the average of the high areas and the low areas. Keep your pH as close to 4 as you can. At 3.8, it will plate slower but a little bit better in the recesses. Increase the agitation to the max practical for the best shot at success.

James Watts
- Navarre, Florida
2007