Letter 37070

Haze in Semi-Bright Nickel [Pennsylvania] 

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Currently we are running a duplex nickel/Cr plating process of Semi and Bright Nickel. Lately we have had what can only be called a haze building up in low current areas on our parts. We have tracked the problem down to our Semi-Bright tanks by simply removing parts after each stage of the plating process and inspecting them. My dilemma is we can not seem to get rid of this problem, we can "manage" it by using small peroxide treatments of about 2gal (the plating tank is 5500gal) but it only temporarily rids us of the problem for about 12 hours; then almost on cue the haze returns. We do not have the facility to batch treat our semi in another tank so we were trying a carbon pack running in a 55gal drum then filtered before returning to the main tank but all this seemed to do was eat up our wetter and carrier which when we add the appropriate amounts back makes the haze problem even worse. Any ideas?

James Ott
plating shop - Harrisburg, PA

Hi James
I ran into a similar problem with a sulfamate nickel tank. With surface tension at 28-29, I'd get the haze. I increased the tension to 33-34 and haven't had any problems with the haze since. You just have to increase it slowly and verify you're not getting pitting as you increase.
It could also be from your MBSA if you're not doing consistant carbon treating. You should be able to get your MBSA level by running a sample through an HPLC.
The peroxide will break down the larger organic molecules so they're more easily picked up by the carbon filter. If you're just adding peroxide without filtering you still have the organics in the tank.

Jeff Marten
Meridian Analytical - Colorado Springs, CO, USA

From your cause and effect relationship I surmise that you are having a problem with organic contamination of the solution. If it returns in 12 hours, you must be putting this contamination back in. I would check the rinses before the nickel and see if you have an organic which is not compatible i.e. a wetted acid salt or additive. Also look for drag over from cleaners of organics and silicates. The bandaid aproach you are using can be improved by using a large carbon canister (15 to 20 lb) externally on your existing filtration. If you are using a carbon packed filter, try putting fresh carbon and filter aid onto the pack each shift.

Gene Packman
- Great Neck, NY

Hello !
I read your hazyness problem from your nickel tank. You said ,you can not do the carbon treatment in your facility,but now the new equipment is available in the market. You do not have to full carbon treatment your nickel bath still you need little amount carbon pack in your filter.

Popat Patel
- Roseville, MI

Hello.........
I don't agree with anybody. I think your problem is brightener-carrier system. Especially if your brightener not to contain some important chemical such as pyridine derivates you have a problems like this. So,If I were you I check or change organic chemical systems for nickel bath. And also I advice you must run hull-cell test panel and compare same current density range for this problem.

Good Luck.......

Emre Tuna
- Istanbul, TURKEY

We also had a similiar problem with our Ni bath. We used a good carbon pack along with filter aid. We actually got this product from MacDermid that is carbon and filter aid mixed all in one, we used carbon filters,we did this for about a week and it seemed to cure the problem quite well.


Regards

Brian C. Gaylets
McKinney Mfg.-Assa Abloy America - Scranton, Pennsylvania, U.S.A.

Thanks for all the suggestions we have managed to get rid of this problem by using the following procedure. First, we cut the Nickel bath 20% and only added back boric acid, stopped running the carbon barrel,lowered the pH to 3.5-3.6, put fresh carbon on the filters and let the surface tension climb back to around 42. The haze dissappeared but then we started to have a "banding" problem in the semi-bright, was determined to be coming from excess brightner in the solution at a low pH. Shorting the bath a few shots of brightner cleared the problem right up. We still have a high organic load in the solution but until we are able to batch treat we are going to try and manage the problems with low pH, high surface tension, and a highly regualted monitoring of ANY organic additive going into the tanks.

James Ott
Plating - Harrisburg, PA

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