Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Proper concentration of nitric use before blue passivation

I'm a University student in Thailand. Now I'm doing a project in cleaner technology program for medium-size electroplating factory in Bangkok, Thailand. I really want some advice from your readers to help me improve many things in this factory. The major problem in this factory is every process here relies on experience of staff-manner. They don't have a specific tool to measure the amount concentration of solution they use or even equipment to weigh chemical they use in each process. Now I want to know what is the proper concentration of nitric acid to use before blue-color passivation, I found from text book to use nitric 5-10 cc/L, is it correct? I will appreciate for your answer.

Nantakorn
zinc electroplating mill - Bangkok, Thailand
2004

Yes, 1/2 to 1 percent is typical.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

2004

Mr Nantakorn,

If you are doing a Cleaner Technology project you could consider the following too as part of Cleaner Technologies that are being used world wide and also in Thailand

1) Stop use of Cyanide Bath . Substitute it with Alkaline Cyanide free zinc Plating.
2) Eliminate hexavalent Chrome and replate it with Trivalent Chromate , in blue chromate.
3) Introduce Counter flow rinses instead of the present systems.
4) Use a Hot 80 centigrade water dip after Chromate ( 30 secs) so that the direct gas flame drying is not needed.
5) Introduce a dragout ( Static Rinse) and re use the water to top up the bath daily.

There are a lot of places in Thailand that will appreciate these cleaner and more economical Techniques.

Regards

Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016

Dear Nantakorn,

I agree with Mr.Asif. My business is a chemical and service company in Thailand. If you want to get more idea.

Best regard,

SIRIMA CHIN.
- Samutprakarn
2004

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