RobertB

Topic: Cloudy Ni Sulfamate Deposit With Pitting

This is from a new bath make-up, to boot. All constituents are to spec and re-checked after treatments (Ni, H3BO3, wetter (SNAP A/M), anode corroding agent, and grain refiner). The in-lab hull cell looks a lot better than the in- bath panel run at 10 ASF (in-bath bright along the borders, cloudy in the center, with what appears to be large, deep, gas pitting throughout. Minimal in number, but unacceptable). Persistent dummying and peroxide/carbon treatment (s) have produced no improvements. We use two pumps with poly filtration (a 1 micron poly-string and a 10 micron poly-spun) and good agitation. I now suspect...

1) The contamination is occurring in real-time and,

2) The contamination is organic in nature

At 1st, I suspected starch from poorly leached anode bags, but the peroxide treatment should have resolved this. Today, I saw that one of our pumps was making contact with one of the anodes (a Lab Series 650- CPVC and poly-pro body). I removed it and am carbon treating /dummying one final time before throwing in the towel. Could the pump and/or poly-spun filter making contact with the anode have been the issue? It's dubious, to be sure, but I'm all out of ideas. Before you get any other ideas, we have a duplicate, and very old, sulfamate bath has has none of these issues (without the Lab Series pump, though).

All suggestions are welcome!


DustinGebhardt

Re: Cloudy Ni Sulfamate Deposit With Pitting

Do you leach the poly filters? They have plasticizers in them that can and will contaminate a bath just as you are describing?


If you were to remove the filters, peroxide/carbon treat the bath, and dummy it, does the problem appear?

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

RobertB

Re: Cloudy Ni Sulfamate Deposit With Pitting

We use poly-string filters for that very reason (free of binding agents, etc.). As far as the poly-spun, we've never had issues with this type of filter before (but it was the filter being used by the Lab Series pump). There are no plans for putting it back in and will keep you posted.

Last edited by RobertB (02/03/2010 - 08:37 PM)

DustinGebhardt

Re: Cloudy Ni Sulfamate Deposit With Pitting

I've always leached my string-wound filters, but then again, I'm paranoid about these things. ;-)

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

surtec

Re: Cloudy Ni Sulfamate Deposit With Pitting

From your description is certainly appears to be organic contamination. Have you been adding back the Snap A/M after each treatment, both peroxide and carbon? Both treatments will effectively remove all of the wetter but none of the grain refiner. Are you using SNHA and at what level?

Sometimes it helps to add wetter before peroxide and carbon treatments. Wetter can 'tie up' some of the organics for easier carbon removal.

Did you use newly received sulfamate nickel concentrate to make the new solution. Or did you have concentrate in inventory.

The strike by INCO has caused some manufacturers to use an inferior nickel source which can cause contamination problems that are difficult to remove except by heavy carbon and peroxide treatments followed by LCD dummy.

Dayton Dailey
Surtec International, Inc.