5. Why use EMI/RFI shielding coatings?

The ideal enclosure for electromagnetic shielding would be a seamless sphere manufactured from highly conductive material, such as copper, silver, or Nickel. Unfortunately, this solution is impractical and would render other functions of the enclosure useless. In the real world (the world of plastics), any enclosure designed in metal may be impractical and cost prohibitive. Often the cost constraints or even the shape required of an enclosure dictates use of plastic injection molded parts. Most plastic, however, is virtually transparent to EMI/RFI. For this reason, coatings have been developed to add shielding characteristics to plastic enclosures. These conductive coatings reflect the interfering radiation. Some common shielding coating materials are silver, copper, nickel and graphite.