The Last Stand of the web we knew & loved: no cost, no reg'n, no popups
As an Amazon Associate & eBay Partner: we earn from qualifying purchases

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

-----

Passivating Super Invar (32-5)

Does anyone have any ideas on passivating super Invar 32-5? I was told a 20% by volume nitric acid from 120-140 °F for 30 minutes.

Greg Wasielewski
- Palo Alto, California
2002

Warm Nitric Acid will remove the iron from the surface and controlled oxidize the nickel in the surface which is the very definition of "passivation".

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2002

Greg,

I'm not sure that Super Invar 32-5 is a corrosion resistant alloy, and therefore passivation may not be a good idea. You'd be wise to contact the manufacturer of your material.

Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York
2002

(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: