BaTiO_3基无铅PTC热敏电阻材料的制备与研究

利用传统陶瓷工艺制备了掺杂(Bi0.5Na0.5)TiO3(BNT),CaCO3和Mn(NO3)2的钛酸钡基无铅PTC陶瓷材料(Bi0.5Na0.5)xBa1–xTiO3-yCaCO3-0.000 2Mn(NO3)2(x=0.005,0.020,0.040,0.080;y=0,0.02,0.04,0.06,0.08),研究了BNT和CaCO3的掺杂量对所制陶瓷微观结构和导电特性的影响。结果表明:试样的晶格常数比c/a、居里温度tC以及室温电阻率ρ25均随着BNT掺杂量的增加而增大;CaCO3的加入能有效降低样品的室温电阻率。当x=0.080,y=0.06时所制得材料的性能最好,其室温电阻率为7×102.cm,居里温度高于150℃,升阻比(ρmax/ρmin)达到103。

Preparation and research of lead-free BaTiO3-based PTC thermistor materials

The(Bi0.5Na0.5)TiO3(BNT) /CaCO3/Mn(NO3)2 co-doped lead-free BaTiO3-based PTC thermistor materials(Bi0.5Na0.5)xBa1–xTiO3-yCaCO3-0.0002 Mn(NO3)2(x=0.005,0.020,0.040,0.080,y=0,0.02,0.04,0.06,0.08) were prepared by the conventional ceramic sintering technique.The effects of contents of BNT and CaCO3 on the conductive characteristics and microstructures of the prepared lead-free PTC thermistor ceramics were studied.The results show that the lattice constant ratio c/a,Curie temperature tC and room temperature resistivity ρ25 of samples all increase with the increasing of BNT content.ρ25 of the sample can be reduced effectively by doping CaCO3.With the content of x=0.080 and y=0.06,the prepared material exhibits the best performance that ρ25 is 7×102 ??cm,ρmax/ρmin>103,and tC is higher than 150 ℃.