Parylene Coating Technology

Parylene is a green chemistry, which is self-initiated (no initiator needed) and un-terminated (no termination group needed) with no solvent or catalyst required. Parylene is applied to electronic circuitry, medical devices, aerospace applications, and automotive assemblies at room temperature to act as protection against moisture, dust, corrosion, chemicals, and temperature extremes that if uncoated (non-protected) could result in a complete failure of the product.

conformal coating chamber

Benefits of Parylene Coating

High Reliability
The vacuum process removes moisture and impurities before deposition of the parylene coating thereby ensuring it will not introduce any foreign substances to contaminate the coated specimens/products. The dimer is over 99% pure, resulting in more truly conformal coating. It has less product failure, and provides better protection for the substrate.

Parylene is a uniform polymer film, which is pinhole free and extremely thin. It provides complete and even thickness coverage on all hidden or exposed surfaces.

Repair Option
Parylene coated electronics are capable of being repaired. The removed parylene areas can be recoated to their original tolerances by reapplying the parylene.

Economical and Clean
The coating thickness can be controlled from 1 to 100 microns in a single operation, and many parts can be coated simultaneously, making the process extremely practical as well as economically attractive. Compared to liquid processes, the effects of gravity and surface tension are negligible so there is no bridging, thin-out, pinholes, puddling, run-off or sagging with Parylene coating. The process takes place at room temperature so there is no thermal or mechanical stress on the product.

Types of Parylene Used

Parylene C
The most widely used dimer, providing a useful combination of properties, plus a very low permeability to moisture, chemicals, and other corrosive gases.

Parylene N
Provides high dielectric strength and a dielectric constant that does not vary with changes in frequency. Best selection where greater coating protection is required.

Parylene D
This variant of parylene provides greater thermal stability and maintains its electrical and physical properties at a higher temperature range. However, it does have a reduced ability to penetrate crevices and is not as flexible as the other two types.

Benefits of Using Parylene
  • Superior barrier to oxygen, moisture, chemicals, solvents, and carbon dioxide
  • A bio-stable, biocompatible coating; FDA approved for various applications
  • Dense, pinhole free
  • Thin highly conformal transparent coating
  • Highly corrosion resistant
  • Completely homogeneous surface
  • Very low permeability to gases

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