Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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

The authoritative public forum
for Metal Finishing since 1989
-----

Discolorization of tin-plated brass without barrier layer

We recently have an issue with brass terminals plated with tin. The customer does not specify an undercoating. We are now receiving complaints about discoloration and "flaking". We have been producing these parts for a couple of years without issue. New QE at the customer and now there is an issue. The part is processed through an oven (by the customer) at ~300° F for a short period of time. The condition shown in the picture is after the oven treatment.

57350-1 57350-2

Any thoughts on why the discoloration is greater now then before?
Is the picture showing "flaking" really flaking or simply the zinc migration?
Thank you.

Mario Pagliuzza
stamper of questionable part - Addison, Illinois, USA
June 21, 2011

Hi,

The major problem would be the zinc migration, one has to do a copper undercoat before going for Tin plating on Brass substrate, or you may face this problem, also it may contaminate the Tin bath.

Praveen Kumar
plating process supplier
Mumbai, India
June 28, 2011

We are facing the same problem, did you figure out what happened?

Thanks

John Bow
- Florence, South Carolina
February 29, 2012

(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: