Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Titanium reaction with HCl and HF

We use descaler (mixture of acids : 50% HCl and 5% HF) in the titanium heat exchanger. We noticed that the titanium discolorized. By this reaction, thus it means that the metal composition of titanium (Grade 7 and 12) be attacked? Can it result in breakdown of titanium?

Ben Riva
- Philippines
2006

Yes. Titanium is attacked by both acids.

Guillermo Marrufo
Monterrey, NL, Mexico
2006

The discoloration may be hydrogen attack from the acids.
Suggest a 30 wt% sulfuric acid + 1% copper sulphate [on eBay or Amazon]solution at 28 °C (100 °F) for cleaning, and a 33.2% nitric acid + 1.6% hydrofluoric acid solution for final brightening.

See letter 38318 and ASTM B600(2002) Standard Guide for Descaling and Cleaning Titanium and Titanium Alloy Surfaces.

Ken Vlach [deceased]
- Goleta, California

Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2006

(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: