Coatings systems: RFI / ESD Shielding

RFI (Radio Frequency Interference) shielding is material that attenuates the energy of electromagnetic waves that pass through it. The purpose of RFI shielding is usually to allow electronic devices to achieve Electromagnetic Compatibility, so they can operate legally and efficiently; but increasingly it is used to protect people from possible negative health effects of electromagnetic radiation. Whatever the application RFI shielding works by being a conductor.

When an electromagnetic wave runs into a conductive material, part of the wave will be reflected, part will be absorbed, and part will be transmitted. If the material is highly conductive, then the reflected and absorbed components will be exponentially larger than the transmitted component. In fact, the decibel scale that is used to measure shielding effectiveness is an exponential scale.

Electrostatic discharge (ESD) is an equalization of electrostatic charges between two objects up to the restoration of the electrical balance. This discharge occurs often within a fraction of a second and having the form of a spark (suspense).

In many cases discharge of static electricity causes latent weakening at sensitive components, which are being used nowadays in all kinds of professional branches. Only after a while and under specific conditions these weakening turn out as defects or faults.