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

Home /
Site 🔍
pub  Where the
world gathers for metal finishing
Q&As since 1989


Automatic Passivation Equipment - and Control Of

We are looking at automating our passivation process. The equipment would wash, rinse, passivate, and rinse the parts in self contained equipment. My main questions are related to maintaining auditable quality standard (particularly NADCAP). How are others making sure the parts are chemically clean prior to passivation (with the equipment we would not be able to do the water break test). Also, what are the standards for determining when the Nitric Acid or should not be used? (I am told we could be able to use the solution for up to 1 year before needing to dump it.)

B. Arnold
Aerospace component mfg - Des Moines, Iowa


B. Arnold:

You should validate your automated process by testing and establishing your defect(out of specification) rate after the cleaning process and after the passivation process. Statistical sampling of your validated online process and testing for cleanliness by an approved method (water break test or surface chemistry analysis) or testing for passivation by approved method (salt spray test or ESCA/Auger chromium to iron ratio testing) would produce auditable quality records.

Nitric acid concentration can be tested as well as the iron concentration in solution. Depending on the specifications to which you are processing, a rule of thumb is iron concentration to remain below 2% by weight.

Thanks, Daryl.

Daryl L. Roll
Costa Mesa, California, USA

Refer to AMS2700 for guidance on the process. Many of our customers are meeting NADCAP requirements easily by validating the process and verifying the results by ongoing tests. Let us know if you need help setting this up.

lee kremer
lee kremer sig
Lee Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner


I understand that 2% Iron is max. in the bath, but can anyone help me out with the procedure.
We are starting a passivation line and I am having trouble finding this one.
I'd appreciate anyone's help.

Micheline Forth
metal finishing - Savannah, GA, USA

none is made possible by supporting advertisers ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

(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:

Chemicals &
Consult'g, Train'g
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"