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How Si-COAT RTV Silicone HVIC Functions
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It is the LMWS in the coating that plays a very essential
role in the function of the coating. Two key properties of
LMWS to bear in mind are its very high dielectric strength
(i.e. high electrical insulation properties) and very low
surface free energy. It is a common phenomenon that microscopic
matter existing in a high concentration in one area but in
a low concentration in another area will migrate from the
area of higher concentration to that of lower concentration.
This is termed diffusion. Because the concentration of LMWS
is greater within the body of the coating than at the surface
of the coating, there is a natural tendency for the microscopic
LMWS to diffuse to the surface of the coating. But, since
the surface free energy of LMWS is so low, it exists only
in a monolayer on the coating surface. That is to say, when
the LMWS migrates to the coating surface, it stops migrating
when the surface is covered in a one molecule thick layer
of LMWS.
Figure 2:
A microscopic monolayer of LMWS covers the surface
of Si-COAT
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