Electrical Properties of Conductive Elastomer as Electrical Contact Material

The conductive elastomer has both electrical and elastic properties. When the conductive elastomer is considered as an electrical contact material, it is possible to obtain conductive and elastic properties in one simple material. Therefore, the concept of metallic electrical contact can be changed to the elastomeric contact. Moreover due to excellent properties of facile shape formation, corrosion resistance, and air tight contact interface, the conductive elastomer is suitable for high density microsized connectors. However as it is very difficult to obtain as low a resistivity as in metals, the effectiveness of the elastomeric contacts is limited. The present study has been conducted to determine the electrical conduction mechanism and to find low resistivity materials. The specimen silicone rubber, in which electrical conductive particles such as carbon and metals were dispersed, was investigated. The resistivity versus conductive particle content, voltage versus current characteristics, resisitivity change in range of room temperature to liquid nitrogen temperature, and conduction mechanisms were discussed. In conclusion the conduction mechanism changes with the conductive particle content. For large content current paths were established by contact of particles, and for small content conduction electrons pass through the gap between particles by the Schottky conduction. Therefore, the resistance of the elastomer consisted of particle resistance, constriction resistance of the contact interface between particles, and the gap resistance.