NTCR effect of BaTiO₃-based PTC ceramics penetrated by rare earth

The modified BaTiO₃-based PTC ceramics were prepared by gaseous penetration of rare earth La, and the change laws of the resistivity at room temperature and the temperature-resistivity properties were studied. The experimental results show that the modified BaTiO₃-based PTC ceramics after La penetration have a significant decrease in resistivity at room temperature, which decreases from 2.7 × 10⁹ to 220 Ω · m, and the resistivity decreases progressively from 220 to 5.8 Ω · m in the temperatures range from 25°C to 500°C, which indicates a significant NTCR effect. Through analyses of XRD, SEM, EDAX and the dielectric properties of the BaTiO₃-based PTC ceramics penetrated by La, the forming mechanism of the NTCR effect was explored, and the physical structure model of the NTCR effect was established.