Switching behaviour and DC electrical conductivity of epoxy-resin/metal-powder composites

Abstract

The DC electrical conductivity of composites made from Epikote 828 resin filled with Cu, Ag, Au, Al, Sn, Pb, bronze and stainless steel powders has been measured at room temperature. Apart from specimens containing Al and stainless steel, all others with a volume concentration of metal of about 20% of more showed switching behaviour. The normally high resistance of the composite was reduced to a few hundred ohms when a potential of about 100 V was applied across the sample and this low resistance was retained as the potential was reduced to zero. The high-resistance state could be recovered by passing a current of a few hundred mA through the sample.