稀土气相扩渗BaTiO3基PTC陶瓷的NTCR效应

采用稀土气相扩渗法制备了La改性的BaTiO3基PTC陶瓷,并对其室温电阻率的变化及温-阻效应进行了研究.结果表明,BaTiO3基PTC陶瓷经La气相扩渗后,室温电阻率从2.7×109Ω.m下降到220Ω.m,在25-500℃范围内,电阻率随温度升高单调递减,从220Ω.m降至5.8Ω.m,产生了明显的NTCR效应.结合XRD,SEM,EDAX以及介电性能测试结果分析了La气相扩渗BaTiO3基PTC陶瓷NTCR效应的形成机理,建立了NTCR效应的物理结构模型.

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 ℃ to 500 ℃,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.