No passwords, No popups, No cost, No AI
we earn from your eBay & Amazon purchases

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Adver-
tise
Help
Wanted
Current
Q&A's
Site 🔍
Search
curated with aloha by
ted_yosem
Ted Mooney, P.E. RET
- Pine Beach, NJ
finishing.com -- The Home Page of the Finishing Industry


  pub
  The authoritative public forum
  for Metal Finishing since 1989

-----

Brown stain on aluminum alloy surface





Currently, our process line found a lot of brown stain on the surface of Aluminium alloy parts. The brown stain presented on Al alloy after cleaning and drying process. The parts are cleaned using detergent ADS902, then rinse by a lot of DI water. Finally, vacuum drying it at temperature 80-85C. The brown stain look like burn mark if visual check by naked eye. When analyst by SEM/EDX, the testing result shown that it's only contain Carbon and oxigen element. I would like to know is it the parts burn with carbon when the parts presented water in high temperature.

Thank you

Tan Christine
bearing catridge part - Balakong , Selangor, Malaysia
2004


Because the part is not clean. A puddle of water can contain enough contaminate to cause the problem. A combination of spray rinses with immersion rinses can get a far better rinse than flowing thousands of gallons of DI water in one or two tanks. Take a look at Ted Mooney's article in the Metal Finishing Guidebook--The art and science of rinsing. Also try incorperating a blow off step prior to the drying step. Less retained water = less stain.

James Watts
- Navarre, Florida
2004



First of two simultaneous responses --

I have encounterd this problems before. Try doing a small testing by using city water (JBA water) instead of DI water. Dry it at the same temperature. Inspect that any brown "burnmark" leave.

YC Chan
- Petaling Jaya, Malaysia
2004



Second of two simultaneous responses -- 2004

Apparently the surfactant from the cleaning detergent is not coming off and when you bake it the organic ingredients break down into carbonacious compounds varing from brown to black, blacker with higher temperature.

To avoid this neutralize the remaining detergent by going through a deoxidizer and then more rinsing as Mr Watts said.

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
probertbanner




(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:

Finishing
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g,
& Software


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