Abstract: The development of PTCR ceramic material with low resistivity and high performance has been recently
become one of the hot spots in the electronic ceramic research in order to meet the requirement of overload protection in automobile and other
low voltage applications. PTCR ceramic material based on BaTiO₃ with electrical resistivity at room temperature <10Ω·cm and
resistivity jump -10⁵ was prepared by conventional mixed -oxide method. The properties of raw material, the constituents of solid solution, and
additives and the schedule of sintering process were studied, and more attention was paid to the method of adding donor and acceptor in liquid
solution. The relationship between composition, process, performance and microstructure during the ceramic preparation was discussed. The device
made of the PTCR ceramic material obtained can be used as an overcurrent protector for door lock motor in automobile.

Key words: PTCR ceramics, resistivity at room temperature, resistivity jump, overcurrent protector for motor