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Because there are mass and volume constraints in space, the packing of components is very tight in many electronic assemblies, which results in very small space between conductors (like solder pads, or leads). If a particle settles in this small space, it may lead to a short circuit. Particles can settle on electronic modules during manufacture, soldering, ground testing, launch or buoyant particles in the zero-gravity space environment in orbit. The short circuit can lead to potentially catastrophic electrical failures in a satellite. Inspite of all efforts to keep satellite assemblies clean and free from contaminants, the possibility of stray particles being present always exists. <ref name = "ref1" />
== Benefits ==* Moisture and corrosive vapors over time may result in corrosion of metals in PCB assemblies. Though conformal Conformal coatings are , though not airtight and thus do not seal electronics from moisture and solvent vapors, they do act as barriers to slow down the diffusion of moisture and corrosive vapors through the polymer vapours before reaching the electronics, slowing down the corrosion of PCB assemblies. <ref name = "ref2">http://www.regenisys.co.nz/wp-content/uploads/2013/01/PB10.108-ConformalCoatings. pdf</ref>* Biological contaminants such as fungus may also lead to degradation; conformal Conformal coatings help to protect PCBs and electronics from biological contaminants, which cause degradation.<ref name = "ref2"/>* '''Structural Integrity:''' It is intuitive easy to see that a conformal coating applied over electronic components on PCBs provides structural integrity and . It also provides protection for to solder joint connections against mechanical vibration and shock and vibration.<ref name = "ref1"/>* '''Tin Whisker Mitigation:''' Tin whiskers are elongated thread-like protrusions of tin that are have been observed growing on surfaces of pure tin in electronics. These thin strands can cause problems if they break away from the base material and cause problems such as electrical shorts and arcing in electronicssurface since they then act like conductive particles which can short connections. The conformal Conformal coating slow downs slows down the formation of tin whiskers when compared to uncoated specimens. Moreover they serve as a dielectric layer to protect electronics from tin whiskers that have penetrated the coating, by serving as a dielectric layer.<ref name = "ref1"/>
== Risks ==
* Mechanical damage of electrical assemblies and electrical damage due to electrostatic discharge (ESD) incurred during handling
* Electrical failures due to stresses induced by the coating on solder joints
* One well-known risk regarding conformal coatings is the potential Potential for stresses to be induced by the coating on electronic components during thermal cycling. This is especially true if the coating is very thick (> 5 mils for many coatings) and if there is a significant coefficient of difference in the thermal expansion mismatch between coefficients of the coating and the substrate materials being coated.<ref name = "ref1"/>
== Precautions and Advice ==
*Spray coating is easy, practical and is thus, the most widely used method *Generally, the best protection is obtained by a 2.0 mil thickness (+/-0.5 mil) will give the best protection*Rinse thoroughly with clean isopropyl alcohol or other cleaning solvent <ref>https://www.niccomp.com/resource/files/ceramic/NCD_HV_Guide_0903.pdf</ref>
While there are risks involved in conformal coating electronic assemblies, they can be mitigated. <br \>
We can avoid undue stresses which cause damage to components and assemblies by applying conformal coating of thickness within a recommended range.
Proper handling, electrical grounding, packaging, and transport of assemblies before, during, and after conformal coating will help to prevent mechanical and electrical damage to PCB assemblies. <br \>
Companies providing conformal coating services in India are:
* pcbconformalcoating.net
* conformalcoatinghelp.com
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== References ==