EMF Solutions

EMF Solutions

EMF Shielding Materials

Shielding devices against electromagnetic frequencies (EMF) is a vital design feature that engineers must consider when developing electronics. Historically, designers could easily improve electromagnetic compatibility by simply twisting conductive wires together, a technique known as shielded twisted pair cabling. Placing circuits in aluminum housing units was another method which blocked incoming electromagnetic signals; however, due to the added weight and cost, aluminum housing units were abandoned in favour of using lighter, cheaper materials such as ABS plastic. While foils and copper tape can be used to shield the plastic enclosures, these materials are prone to tearing, creating gaps in the shield where radiation can leak from, effectively reducing the shielding efficacy. In these situations, it is more practical to consider an emf paint which is far more conformal and durable than foils.

EMF Solutions
Figure 1: ABS housing units coated with acrylic EMF Shielding Paint including carbon, nickel, silver, and copper

EMF Shielding Paint

EMF shielding paints combine binder systems such as acrylic, epoxy and polyurethane with high loads of conductive filler such as carbon, nickel, and silver. When applied to non-conductive surfaces like plastics, glass and ceramics, the paint coalesces as a conductive film with resistivity values as low as 10-5 Ω cm. The choice of binder system influences coating properties like adhesion and resistance to various environmental stresses, whereas the choice of metal filler influences electrical conductivity, shielding attenuation, and moisture resistance (in particular, how likely the flake will oxidize when wet). The spider diagrams below compare the different binder systems along with metal fillers.

Conductive Filler Performance Spider Diagram
Figure 2: Spider diagrams that compare the binder system (left) and conductive filler (right). 5 represents the highest performance and 1 the lowest.

MG chemicals have a full line of conductive coatings for protection against EMF that covers a range of substrate materials, environments and overall shielding requirements. Please get in touch with Technical Support to discuss your EMF protection needs.

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