Ask the Experts
January 19, 2018 - Updated
December 7, 2009 - Originally Posted

SMT Component Lead Oxidation

How do you suggest we remove oxidization from SMT component leads? The component leads are seriously oxidized due to long time storage.

E. W.

Expert Panel Responses

Since you had observed the oxidationin SMT Component you have to check the Moisture sensitive level of the component. The JDEC standard deeply explain the self life of the SMT components as well as the storage condition. If the component is to old (i.e the component stored for long time more than the self life), I would suggest not to use the component. The JDEC standard will help you more in this issue. The JDEC standard also explain how to increase the self life of the component.

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.

This kind of depends on the termination style - leaded components can be pre-tinned using more active flux if necessary to break down the oxide layer. Chip components are trickier and replacement with new components should be considered. Prevention, of course, is the preferred route and if long term storage is likely then vacuum packing is a good option to prolong solderability shelf life.

Bryan Kerr
Principal Engineer - CMA Lab
BAE Systems
Bryan Kerr has 35 years experience in providing technical support to PEC assembly manufacturing. His experience ranges from analysis of materials and components to troubleshooting and optimizing, selecting reflow, cleaning, coating and other associated processes.

I would suggest you contact your solder supplier. They can evaluate the solderability of your components and recommend a suitable flux.

Edward Zamborsky
Regional Sales Manager
OK International Inc.
Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

The answer is to retin the leads to remove the oxidation and prepare the leads for the SMT operation. A wetting balance test can be performed to insure the leads meet solderability. The leads can be dipped in either lead free or leaded flowing solder pot.

Mark McMeen
VP Engineering Services
STI Electronics Inc.
Mark T. McMeen is STI Electronics Inc.ʼs Vice President of Engineering Services. He oversees the daily operations of the Engineering Services division of STI. He has over 18 years experience in the manufacturing and engineering of PCBs.

As an internal fix, if it is not verydifficult, fluxing the components on a FR4 board and reflow them on a mild ovenprofile followed by a cleaning cycle should fix your problem.

Georgian Simion
Engineering and Operations Management
Independent Consultant
Georgian Simion is an independent consultant with 20+ years in electronics manufacturing engineering and operations.
Contact me at

Reader Comment
After opening your vacuum package, store your components in a dry cabinet that uses nitrogen (very low flow) as inner atmosphere control. Nitrogen is dryer than air and has no oxygen. Good dry cabinets can reach very low oxygen levels inside it very fast after door openings. Residual oxygen level at low concentrations inside dry cabinets <100 PPM. So, no oxidation during components storage time.
Luiz Felipe Rodrigues, Air Liquide

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