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Reply To: | TechNet Mail Forum. |
Date: | Mon, 20 Oct 1997 10:36:42 -0400 |
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In addition to what Graham has said about salts under conformal coating,
consider also that when a salt crystal encounters water, which WILL come
through conformal coatings, it will expand up to 200 times its original
volume, creating a localized blister. This effect is often referred to as
"mealing". Once the blister is formed, it is a place for water vapor to
collect and condense. Liquid water together with the original salt material
forms an electrolytic solution, which is generally detrimental to circuit
reliability.
Doug Pauls
CSL
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