Interfacial breakdown phenomena between two EPDM surfaces

The phenomenon of interfacial AC and DC breakdown is the subject of this paper. Two pieces of EPDM rubber were pressed together and a special jig was conceived so as to provoke arcing along the interface. The voltage at which breakdown occurred was measured and its dependence on the type of voltage (AC or DC), the interfacial pressure (0 to 100 kPa range) and on the presence of silicone grease was established. In the absence of silicone grease at the interface, DC breakdown voltages were two times greater than those for AC and both showed a linear dependence on pressure. With silicone grease, both AC and DC breakdown values were consistently higher; in the case of AC, values reached a plateau at higher pressures whereas for DC, values showed a slow linear increase with pressure