Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989





-----

Colour variation with trivalent dips after zinc plating





June 4, 2010

Hi, I run a electroplating plant on the Central Coast of New South Wales. Australia. We electroplate our own "in house" products nickel on a automatic line, we also do zinc plating for external customers. We have recently converted to trivalent"yellow" and "silver/blue" dips after our zinc plating (acid-chloride). We have encountered two problems. Firstly colour variation with the yellow dip on a single component. And secondly the trivalent yellow gives an extremely light yellow colour, one customer called it "champagne" or "chardonnay" that's how light it really looks. Can you please give me some advice on these problems? Thank you..... Pete

Peter Hordern
Plating Supervisor, Metallurgist. - Gosford N.S.W. Australia



June 4, 2010

Hi, Peter. Trivalent chromating is completely proprietary and based on several different approaches. It is claimed that the "thick film" trivalent chromates can give a rich yellow color. However, if I were you, I would lobby for getting the customer to accept "champagne" by explaining that the origin of the deep yellow color that he is familiar with is the toxic, carcinogenic, hexavalent chromium slathered onto the parts :-)

The dark yellow color IS hexavalent chromate and there could be future value for him in making sure his parts aren't that color. You never know when the Sierra Club, or Audobon, or PIRG, or EPA might start calling public attention to the presence of hexavalent chromium compounds on articles that people touch.

Regards,

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


none
finishing.com is made possible by ...
adv. 
spacer gets replaced with bannerImages

Q, A, or Comment on THIS thread -or- Start a 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    -    ©1995-2023 finishing.com, Pine Beach, New Jersey, USA