No passwords, no registration, no paywalls, no popups, no AI

As an Amazon Associate & eBay Partner we earn from affil links

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

Search our quarter-million Q&As

Home of the finishing HOTLINE since 1989

-----

Thick black foam in passivation tank ?

My name is Mike Nelson I am the Special Processes Manager of Machine Shop. I have a passivation line set up to ASTM A967 nitric 1. This afternoon I found a thick black foam floating on top of my passivation tank. The tank tested good 24% nitric acid 2.5% sodium dichromate. Has anyone seen this before? If so can you tell me what it is or what caused it? Thank you for any help you can provide

Mike Nelson
Special Processes Manager - Chattanooga Tennessee
January 14, 2011

Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.

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: