Effect of processing on the positive temperature coefficient of resistivity in lead metaplumbate/polyethylene composites

Abstract The positive temperature coefficient of resistivity (PTCR) effect of a barium metaplumbate/polyethylene [(BaPbO ₃ )/PE] composite with 12 vol% of BaPbO ₃ was studied. The composite samples were prepared by hot‐pressing a mixture of BaPbO ₃ ceramic and high‐density polyethylene powders around the melting point of polyethylene. The composites exhibit a pronounced PTCR effect of up to a six‐decade increase in resistivity within a narrow range of temperature (∼10°C). The dependences of the room temperature resistivity and the magnitude of the resistivity jump on the pressing and annealing temperature, and the electrical behavior after repeated heating‐cooling cycles were investigated. The fracture surfaces of the composite samples were examined in a scanning electron microscope in order to correlate the electrical behavior with the microstructure.