| BaTiO3 is a kind of very good insulated material, whose room temperature resistance can reach 1010~1012??cm. In 1995, Haayman and others discovered that BaTiO3 ceramics would produce positive temperature coefficient of resistivity(PTCR) by putting little donor lanthanon in it, whose room temperature resistance can lower to10~102??cm. Now, PTCR material is facing a challenging problem of how to lower the room temperature resistivity and raise the PTC jump at the same time.This experiment adopted traditional technology of preparing PTCR ceramics. Ni/Ti/BaTiO3 composites were fabricated by adding Ni and Ti into BaTiO3 calcined powder. To achieve low room-temperature resistivity, the samples were sintered at reducing atmosphere, and to achieve better PTC effect the samples needed heat treatment and the heat treatment was in air atmosphere.In this article, the effects of the Ni content, Ti content on the electric properties and PTC effect of the Ni/Ti/BaTiO3 composites were discussed, and the influences of technology crafts on the composites were analyzed. By analyzing the data of the experiments, the parameters of the processing condition were manipulated.Through the experiment a conclusion is obtained. Adding Ti to Ni/BaTiO3 composites can protect Ni from being oxidated, so the r.t. resistivity can be reduced. A part of Ti is oxidated to be TiO2, excess TiO2 lead to the birth of Ba vacancy, which can rise the PTC jump. The reducing atmosphere is made of graphite which is good for rising electric properties. The best sinter temperature is around 1250~1270oC. The best temperature of heat treatment is 800oC. In this condition, r.t. resistivity can be reduced to1~2??cm, the Rmax/Rmin can hold on 40~50 and the resistivity-temperature coefficient can keep 10%?oC-1.
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