EMI/RFI Shielding

With lightweight requirements, higher frequency CPU’s, higher power devices, and increased use of personal electronics such as cell phones and PDA’s there is an increasing need to shield sensitive electronics from spurious and stray electromagnetic radiation. Thermal spray techniques are suitable for such applications. Electromagnetic interference (EMI) and radio frequency interference (RFI) can be mitigated with the use of thermal spray coatings. Attenuation levels of 80 dB are practical.

When engineering an EMI/RFI shielding coating Thermal Spray Technologies uses its strong expertise in materials engineering, its strength of understanding of the processes of thermal spray, and its understanding of EMI/RFI shielding issues. The combination of this knowledge provides application specific solutions to our customers’ electrical noise problems.

Coating Materials

Some of the more common materials Thermal Spray Technologies uses to provide EMI/RFI shielding include a variety of pure metals and metal alloys such as aluminum, copper, tin, and zinc.

Substrate Materials

Thermal spray EMI/RFI coatings can be deposited onto virtually all substrate materials. Typically, these coatings are applied to materials that are transparent to noise and include carbon-based materials such as carbon composites, polymers, paper, wood, etc. The low thermal transfer of thermal spray processes permits the coating of these heat sensitive materials. Permanent structures, including concrete, are coated using thermal spray to produce a Faraday cage.

Examples

Lightweight electronic enclosures are coated to provide EMI/RFI shielding that prevents stray radiation from either entering or exiting the enclosure to protect the onboard electronics as well as peripheral electronics. Noise sources include switches, oscillator circuits, transformers, CPU’s, etc. Plastic cases for consumer products like computers, cell phones, calculators, radios, and more can be coated economically. Thermal spray can be also used to suppress commutator noise from motor brushes by coating the enclosure near the motor. Industrial applications include process control enclosures, high-energy enclosures such as x-ray equipment, motor controls, etc.

Carbon fiber composite component coated for EMI/RFI shielding