We search for industry news, so you don't need to.
|
|
|
| February 10, 2012
|
| |
Circulation Over 51,000
|
|
November 25, 2009
Cause of Yellow/Brown Discoloration
What is possible cause of "yellow/brown" discoloration on a silver immersion circuit board assembly after the oven reflow process?
G. G.
|
This is either contamination on the surface burning off or oxidation of the silver starting to happen.
|
Steven Adamson
Market Specialist
Nordson ASYMTEK
Market Specialist for Nordson ASYMTEK. Mr. Adamson worked for Kodak, Motorola and Plessey, ICL in the UK with 5 US and 2 UK patents. He was awarded a HNC in electrical engineering and was 2008 President of IMAPS. Mr. Adamson was a respected mentor in the electronics industry. He passed away October, 2011. Learn about the Steve Adamson Memorial Annual Scholarship Fund.
|
|
Yellow / Brown color on silver is silver tarnish which is a combination of silver sulfide and silver oxide which occurs over time as silver is exposed to air. Heat accelerates silver tarnishing, so it is easily visible after the first reflow cycle.
Unfortunately silver tarnish can cause solderability issues and subsequent reflow or wave soldering may be difficult.
|
Mike Scimeca
President
FCT Assembly
Mike Scimeca created FCT Assembly after the purchase of Fine Line Stencil, Inc., and consists of two major operations: stencil manufacturing and the manufacturing of electronic assembly products such as solder paste, flux and solder bar.
|
|
The possible cause for yellow/brown discoloration are the flux viscosity and the reflow profile.
You need to check the flux property like activation temp, viscosity, helide contains in the flux and temperature profile of soldering.Also check the amount of flux apply to the solder joints.
|
Sandip Thakor
Quality Engineer
Matrix Telecom Solution P Ltd
Sandip Thakor has 9 years of experience in electronics industry specializing in soldering technology. Thakor has experience in lead free installation, process optimization and developing quality standards.
|
No additional comments have been submitted.
|
| Submit a comment - Add to the discussion. |
|
|
|
|
|
