Meaning
Composite material used for electromagnetic interference shielding and electrical grounding in electronic enclosures. A conductive elastomer combines the flexible properties of a rubber base with the electrical properties of metallic fillers. These materials provide an environmental seal while simultaneously allowing current to pass between two mating surfaces.
Filler Morphology
Particle shapes inside the polymer matrix determine the electrical path. Silver coated glass or nickel coated graphite particles provide the necessary contact points for conductivity. These particles must touch each other to form a path through the gasket.
Compression Set
Permanent deformation occurs when the gasket is squeezed beyond its elastic limit for an extended period. The conductive elastomer loses its ability to spring back and maintain a gas tight seal. This loss of force degrades the shielding effectiveness over several years of service.
Proper groove design prevents the material from exceeding its compression threshold. Detailed testing ensures the material maintains its shape across the full temperature range of the device.
Contact Impedance
Total resistance through the interface depends on the pressure applied to the surface. Lower pressure results in fewer contact points between the filler particles and the enclosure wall. High pressure increases the contact area but risks damaging the polymer structure.
Engineers measure this value in ohms per square centimeter to verify the performance of the shielding.
