Where the world gathers for
plating, anodizing, & finishing Q&As since 1989

-----

How to analyse aluminium content in chromadizing tank

October 10, 2012

Q. Sir I work in a pretreatment manufacturing unit. Please tell me how to analyse the aluminium content in chrome tank.

Nirbhay Goswami
- Rudrapur, Uttrakhand, India

----
Ed. note: the word "chromadizing" isn't used much in the USA to our knowledge, but we believe it means chromate conversion coating of aluminum.

October 12, 2012

A. I'm not familiar with chromadizing but from what I can gather it is just treating the metal with chromic acid. If so, take a 20 mL sample of the bath and dilute it to 100 mL with DI water, then titrate with .5N NaOH to a pH of 3.2. Call this "A". Continue titrating to a pH of 4.8. Call this "B". To get your aluminum content it is
(B-A)x .430

Scott Merritt
- Eastman, Georgia, USA

October 30, 2012

A. My apologies, I forgot to include the factors for free and total chromium.
To determine free acid you multiply "A" x 0.334
To determine total acid multiply "B" x 0.334

Scott Merritt
- Eastman, Georgia, USA

finishing.com is made possible by ...
this text gets replaced with bannerText

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: