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July 6, 2008
Humidity and Corrosion
We are experiencing a corrosion problem with humidity or small droplets of moisture building up on components.
What do you recommend for the best corrosion protection out there to reduce this problem?
Mark Wiltse
Action Consulting
This "Ask the Experts" page has been viewed 552 times.
Ask the Experts Comments
July 6, 2008
It sounds like you need more than one thing.
First, make sure the components stay sealed in the vacuum packed packaging in which they were shipped until you absolutely need the components. Once they are opened, re-seal the packaging as soon as possible using a vacuum sealer.
Second, if you must have the packaging open, use a "Dry Box" to store the opened packages. A dry box is a cabinet with humidity control built in. The Dry Box maintains a LOW humidity environment for component and PCB storage. There are a number of manufacturers of Dry boxes, you have to decide which one fits your operation the best.
Third, Nothing beats a good factory humidity control system. On the plus side, I would think you are not having many ESD issues with such high humidity. However, as you are seeing, the upper extreme of humidity can be detrimental.
Kris Roberson, Senior Technical Instructor
BEST, Inc.
kroberson@solder.net
 Kris Roberson has experience as a machine operator, Machine and Engineering technician as well as an Electronics and Process Engineer for companies as Motorola, US Robotics. Kris has earned the highest Certifications awarded by the IPC in electronics training, being certified as an Master Instructor in IPC7711 / 7721, IPC A-610D and IPC J-STD 001D.
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July 6, 2008
Corrosion products can come from anywhere and moisture is the element that makes it happen. My first thought without seeing the product would be to conformal coat the product, to reduce the amount of moisture reaching the components.
Secondly I would check the cleaning process used after the soldering operation of these boards to make sure they are clean and no flux residues are left behind from that operation. The ability of flux to absorb moisture is high and under the right condition can create all kinds of corrosion and dendritic growth.
These are two quick thoughts, hope it helps.
Leo Lambert, Vice President, Technical Director
EPTAC Corporation
leo@eptac.com
 At EPTAC Corporation, Mr. Lambert oversees content of course offerings, IPC Certification programs and provides customers with expert consultation in electronics manufacturing, including RoHS/WEEE and lead free issues. Leo is also the IPC General Chairman for the Assembly/Joining Process Committee, covering areas of mounting, soldering, solderability and assembly.
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July 6, 2008
It sounds as if your product is subjected to a condensing environment in its end application. In such cases, the best approach would be apply some sort of a conformal coating or potting compound to the board after the assembly process but before it is sent out to the field. These types of products are commonly used to act as a moisture barrier in several varieties of electronics applications.
Brian Smith, Global Sales & Marketing Manager
Kester Paste
bsmith@kester.com
 Mr. Smith is the Global Sales & Marketing Manager for Kester and has worked in the soldering materials industry since 1994. He holds a B.S. degree in Chemical Engineering from the University of Illinois and has an intensive background in soldering materials technology and SMT process optimization. He has visited hundreds of electronics assembly companies globally and has assisted many customers with lead-free qualification and conversion efforts. He has achieved Certified Process Engineer status through the SMTA.
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July 6, 2008
A conformal coating will solve this problem for you. There are many different conformal coatings on the market, the most suitable will depend on your application and processing capabilities. If you can supply me with more information on your application and what facilities you have in production then I can offer more assistance.
Alternatively, you can visit Electrolube website for more information. Depending on the quantity of boards you produce you may want to look at an acrylic, such as APL in aerosol form, as a starting point.
Jade Bridges, R&D Manager
Electrolube Ltd
jade.bridges@hkw.co.uk
 Based at the head office in the UK, Jade Bridges is the R&D Manager for Electrolube. She is responsible for new product development and technical support within the Electrolube range. Her expertise is in conformal coatings and encapsulation resins, however her knowledge spans throughout the Electrolube range. This also includes thermal management products, contact lubricants and electronic cleaning.
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