Applications - Parylene Engineering
Parylene coating has been commercially available for over 30 years and its properties are use in a wide range of applications.
The Parylene film is chemically inert, no acid or alkaline material will attack it in any significant manner. The FDA has approved the Parylene film for human implantable devices. The Parylene film possesses superior dielectric properties, approaching 8000 volts for 1 mil thickness.
Circuit Boards: Coatings are thin, truly conformal, stress-free and resistant to solvent and fungal attack. Good adhesion minimizes ionic conduction at the coating-substrate interface and strengthens solder joints. Low dielectric constant minimizes loading in high frequency applications.
Good adhesion to ceramic substrates. Good throwing power enables coating within spaces as narrow as 10μ. Interior of packages may be coated via a 1mm hole - coating strengthens wire-bonds and immobilizes particles of debris such as solder balls.
Ferrite cores and bobbins are coated to reduce friction and abrasion in coil forming and to prevent chipping and dust formation. Coating cast metal magnets gives corrosion protection and electrical insulation. Accelerometers, strain gauges, pressure sensors etc may be coated for electrical insulation and environmental protection.
Rubber and Plastics:
In the coating process the monomer is able to penetrate the surface of rubbers and plastics giving very good adhesion. A 2μ coating imparts dry lubricant and wear resistance characteristics to the surface. For example silicone rubber keypads are coated to improve the 'feel' of the surface and to protect the printing and 'O'-rings are coated to reduce friction in, for example, syringes. A thicker coating improves chemical and solvent resistance.
& Instrumentation: The
excellent optical and barrier properties of
Parylene and the stress-free nature of the
coatings find many uses in this field,
particularly in protecting
moisture-sensitive elements such as
potassium bromide windows. Freestanding
films of Parylene may be produced by
stripping the coating from suitably prepared
glass plates and are used to produce windows
and other components in instrumentation.
Components: Because Parylene
has excellent barrier properties, cannot be
hydrolytically degraded in the corrosive
biological environment and is capable of
penetrating and coating the bore of narrow
tubes it has many uses in this field:
- Protecting electronic circuitry and
other components for example in
- Protecting the body from toxic
- Adding surface lubricity to improve
the functioning of catheters, probes,
- Trapping and preventing the
production of surface debris in, for
- Cardiac assist devices
- Electrosurgical tools
- Mandrels and molds
- Elastomeric seals
- Needles and epidural probes
- Medical electronics
unique application process and the
predictable barrier properties and
mechanical strength of Parylene coatings
have also found other interesting
- Strengthening paper in old
books and manuscripts: Books may be
coated without dismantling them.
- Preserving archaeological
artifacts particularly those
from underwater sites such as the
Titanic, Coating explosives and solid
rocket fuels to make them less moisture
sensitive and to modify other
- Ultra-thin Parylene
conformal coatings provide magnet and
ferrite core applications excellent
dielectric properties. With a
lower dielectric constant, lower
dissipation factor and high dielectric
strength compared to industry-standard
coatings, Parylene coatings are uniquely
suited for electrical insulation on
miniature wire wound components.
Parylene coatings also provide
protection against abrasion damage that
may occur during the winding process.
Finally, Parylenes dry lubricity (low
coefficient of friction) is also
beneficial in the winding process.
- The use of adhesive tape as
insulation between winding and metal
component is a well established process
however as components get smaller,
application of tape becomes difficult,
in many instances resulting in less
yield of acceptable parts. A
coating of Parylene can virtually
eliminate faulty components while
improving electrical performance.
- Molded plastic NdFeB magnetic
components are fragile and an additional
advantage of a Parylene coating is
increased strength. NdFeB material is
also very susceptible to corrosion from
atmospheric moisture. The
extremely low water vapor transmission
properties of Parylene provide excellent
protection against corrosion.
- Parylene coatings often also offer a
reduction in processing and
labor costs since it is
possible to coat many thousands of parts
simultaneously using a tumble system
during the vapor deposition process.
- Liquid Coatings do not provide even
coverage across all surfaces of a coil
form. Build-up of conventional coating
material on a coil form can restrict
windings capacity compared to an
uncoated form or a form with a thin and
uniform Parylene Coating. Thin
and uniform Parylene coating has little
effect on the shape and capacity of a