Effect of voltage on the conduction of a high-density polyethylene/carbon black composite at the NTC region

The time dependences of current and Joule heating under various voltages are studied to high-density polyethylene (HDPE) filled with carbon black (CB) of 0.082 in volume at an ambient temperature of 158 °C located at the region of negative temperature coefficient (NTC) of resistivity. The composite shows either a transition from the intrinsic to the steady conductions or an irreversible electrical breakdown depending on the applied voltage. The intrinsic conduction in the absence of Joule heating is explained combining two electron tunneling processes while the electric field induced NTC effect is related to the production of additional conducting pathways resulted from cold-emission.