Technical Library | 2015-10-22 17:37:28.0
The objective of this study is to evaluate conformal coatings for mitigation of tin whisker growth. The conformal coatings chosen for the experiment are acrylic, polyurethane and parylene. Also included in this paper are tin whisker inspection results of tin-plated braiding and wire that was exposed to an environment of 50°C with 50% relative humidity for over five years.
Technical Library | 2013-10-22 07:38:42.0
In conformal coating many components and printed circuit board locations must remain uncoated due to the insulating nature of the coating. The purpose of the conformal coating masking materials is to prevent migration of the conformal coatings into components that need to clear and designated keep out areas. This applies to both liquid conformal coating and Parylene processing. Get this basic process wrong and it can be a big problem, leading to the next stage of either repairing the conformal coating leak, stripping the conformal coating off the circuit board, removing a component to replace it or scrapping the board. This paper reviews typical masking application methods in conformal coating and provides advice on minimising problems.
Technical Library | 2015-03-26 19:16:03.0
Nickel-palladium-gold-finished terminals are susceptible to creep corrosion. Excessive creep corrosion can result in device failure due to insulation resistance loss between adjacent terminals. The mixed flowing gas test has been demonstrated to produce creep corrosion on parts with nickel-palladium-gold finished terminals. Conformal coats are often used to protect printed wiring assemblies from failure due to moisture and corrosion. However, coating may not be sufficient to protect lead terminations from failure.In this study, acrylic, silicone, urethane, parylene, and atomic layer deposit (ALD) coatings were examined for their effectiveness at preventing corrosion of nickel-palladium-gold-finished terminals.
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