Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site

-----

Ideal Sequence for Alkaline Zinc Plating

none
adv.
this text gets replaced with bannerText
spacer gets replaced with bannerImages
February 6, 2022

Q. For New Alkaline Zinc the below process Sequence can be done in Auto Line:

Soak-1
Soak-2
Anodic
Water Rinse - 2 Stations
Acid Pickling
Water rinse - 2 Stations
Activation
Zinc Plating (5 Station)
Water Rinse - 3 Stations
Nitric Dip
Water Rinse - 2 Stations
Passivation
Water Rinse- 3 Stations
Top Coat
Dryer

The Pre Treatment is enough for Zinc Plating or we need to add second stage of Anodic and Second stage of Acid Dip?

Srinivasan Krishnan
- Chennai Tamil Nadu, India
^


February 2022

A. Hi Srinivasan. Although I have seen double cleaning - double acid cycles, it is rather unusual and I'd guess that less than one shop in a dozen uses such. Your treatment cycle sounds quite robust and fine to me. In fact, rinsing after the nitric dip is probably not necessary. Whether 5 zinc plating stations is enough depends on your production rate and desired plating thickness; it might be enough but sounds light to me.

To be fully economically viable, the number of treatment steps, the number of programmed hoists, and the production rate need to be carefully balanced. With this many treatment steps you'll probably want 2 hoists. And with two hoists you may want more than 5 plating stations especially if the production rate is optimized with "put & take" in the plating tank (meaning one cell is always empty).

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^


April 30, 2022

A. What is the "Activation" step before the plating tank in your line? Normally here I have an anodic cleaner tank filled with sodium hydroxide to push the smut out of the parts left over from the acid pickling.

Also in regards to rinsing after Nitric, in my view, the necessity of this depends on to what scale the drag-in of nitric has an effect to the chromate tank.

As an example, many chromate solutions are nitric based in the sense they have nitric acid in the formula, so drag in of nitric wouldn't be an issue. However some Hexavalent black solutions are not nitric based, and the TDS mentions nitrates are a contaminmant and can lead to discoloration. As such I have a rinse tank after my Nitric for this reason.

Boris Siljanoski
- Perth, Australia
^


May 2022

thumbs up sign Hi Boris. Thanks for advising that not all chromates are nitric-acid based; I hadn't realized that.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2022 finishing.com, Pine Beach, New Jersey, USA