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topic 12212

Small milky points on bright chrome over bright nickel plated brass parts


 

Q. We do bright chrome plating over bright nickel plating on parts of max 4 dm2 surface area. Small milky points appear on our plated surfaces at the areas which the last water drops leaves the part when the bar is waiting over the tanks. This deposits can be removed by further polishing after plating process. Thinking that the potential reason is the activation process, we have made experiments on activation but no positive results are achieved.

Thanks for your interest,

Ozkan Bekiroglu
- Bozuyuk, Bilecik, TURKEY


 

A. Are you using Demineralized water in rinse?

Payal Mag
- Charlotte, North Carolina


 

We use demineralized water for rinsing between nickel and chromium baths.

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

A. Hi Ozkan.,

Your milky spot can be from a high level of wetting agent from the nickel solution.

Regards,

anders sundman
Anders Sundman
3rd Generation in Plating
Consultant - Arvika, Sweden



 

Hi Anders;

The wetting agent concentration of the nickel solution is between the limits according to our analysis. We have achieved a different result during our experiments. We have shaken the parts 2 times in the demineralized water rinse tank just before the chrome activation process and the ratio of the faults decreased but did not totally disappear.

Regards,

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

A. Ozkan,

I still believe this problem you have is what we call "withe hourse". Are you sure that deionized water is clean and free from contamination from your nickel solution additive. Did you have the possibility to make a rinse dip in water solution with a little contents of sulfuric acid 1.5 percent before chromium plating. Also did you have this problem for other materials?

Regards,

anders sundman
Anders Sundman, 4th Generation Surface Engineering
    Sundman & Nylander AB
Arvika, Sweden



 

A. Try dipping the work in the chrome dragout tank immediately before entering the chrome tank

Tim Strickland
- Auckland, New Zealand


 

thumbs up signWe will try your both suggestions and write about the results as soon as possible.

Regards,

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

Rinsing the tank into a %1.5 sulfuric acid rinse tank before chrome activation process did not solve the problem.
Dipping the parts into the chrome dragout tank before chrome plating didn't solve the problem.

I could not clearly understand the question about the material, but if the subject is the base metal, we see the fault only on the plated brass parts.

Regards,

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

Q. The concentration of our chrome dragout tank is high. Maybe the problems occur because of that reason?

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

A. If you turn some of the components upside down after they come out of the nickel and some different ones upside down after the nickel rinses just prior to chroming what happens to the white spots. Are they still all on the bottom of the work or are some on the top of the pieces you turned.

Tim Strickland
- Auckland , New Zealand


 

The hanging style does not change the place of the defects. They still occur at the bottom points of the parts where the last drops leave the part.

Regards,

Ozkan Bekiroglu [returning]
- Bozuyuk, Bilecik, TURKEY


 

A. Try spraying the plated articles with DM water after Nickel plate and may be avoid nickel dragout.

Jeevan
- Ujjain, MP, India


 

A. 1. Add 3:1 ratio of wetter/additive to the brightener ratio to the nickel plating bath.

2. Try to transfer the Nickel to its dragout and rinse tanks before the water dries as a spot. Maintain the bath temperature at 50 °C instead of 60 °C which makes parts dry .

3. I do hope the parts stay under clean water after Nickel till they are chromed ?

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind supporting advertiser
Bangalore, Karnataka, India

saify logo


April 13, 2013

A. Dear Ozkan,
We faced the same problem in our Ni-Cr automatic plating line, in which the air exposure time is 30 seconds when arm shift to next position. We were also using the de-mineralized water in rinses between the Nickel & Chrome. We also know that demineralized water is strongly recommended in all plating lines. I suggest trying normal water of TDS-350 to 400 and pH 7.0 to 7.5. This is some reaction which occurs due to air exposure time.

RAJESH BASSI
Electroplating industry - Ludhiana,Punjab,India



July 28, 2014

Q. Well, I am thankful for the literature you provided on net regarding chrome plating, but I need to know about the defects of chrome plating. How to away from them?
Problem-1 - White spots (looks like water spot)
Problem-2 - Ring marks (at whole diameter of needle if the product is brass pipe)

Hope you will clear me.

Regards,

agam sharan mathurManager | Quality
for plating - jaipur, rajasthan (india)


July 2014

Hi Agam. Troubleshooting such problems isn't easy, but if you send some photos to money@finishing.com, to at least alleviate misunderstandings about what these defects look like, it will probably help. We appended your inquiry to one of at least 3 long threads on the same subject -- you might want to also look at letter 35342 and 45884. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



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