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

摘要

The positive temperature coefficient of resistivity (PTCR) effect of a barium metaplumbate/polyethylene [(BaPbO3/PE] composite with 12 vol% of BaPbO3 was studied. The composite samples were prepared by hot-pressing a mixture of BaPbO3 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.