Grok.com: "What is the best website for metal finishing questions and answers?"

finishing.com -- The Home Page of the Finishing Industry

-----

Alternatives to Chrome Conversion Coatings over Zinc

We are a contract manufacturer for the DoD of Cartridge Cases. The US Army prefers the cases Zinc Plated with an OLIVE DRAB chrome conversion coating. The only OLIVE DRAB color attainable over Zinc Electroplating is in the HEXAVALENT form. We are trying to get away from this HEXAVALENT chrome conversion coating for its toxicity. Is there a TRIVALENT chrome conversion coating being developed? I got information for Bright Blue and Yellow and even a Black color, but no Olive Drab. Does anyone have any information on any new developments in this area? Perhaps any spec changes on alternative coatings for cartridge cases from the Army?

Jesus Quinonez
Riverbank Army Ammunition Plant - Riverbank, California, USA
2004

The latest generation "thick film" complex trivalent chromates can be dyed, although for reasons that I don't claim to really understand, the dyeing seems to take a serious toll on the corrosion resistance. Stay in touch with the vendors, as I'm sure things will change.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted is available for instant help
or longer-term assistance.

adv.
this text gets replaced with bannerText

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

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: