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本文研究了用液烧结制备pb5mol％,含和不含Ca7mol％的以BaTiO_3为基的PTCR半导体材料。讨论了第一烧结温度对样品的平均晶粒尺寸低温电阻,最大电阻率的变化和电压灵敏度的影响,掺杂Ca的材料能提供较好的PTCR性能。 液相烧结已经成为制备BaTiO_3半导体陶瓷一种通用的方法。液相烧结重复性比较高,烧结温度又比较低,这对于大规模生产来说是很重要的,关于烧结温度掺杂和非化学计量在晶粒生长和电性能方面的影响已有大量的报导。居里温度为120℃的纯BaTiO_3报导得最多。 本文提出了含pb5mol％以取代阳离子Ba,居里温度140℃的材料的实验结果,同时把它们和pb外还含Ca7mol％的材料进行了比较。添加钙是因为它能产生较细的显微结构。烧结工艺亦影响显微结构。我们就平均晶粒尺寸,50℃时的电阻率,正电阻温度系数(PTCR)的突变和电压灵敏度几个方面讨论了添加Ca和烧结曲线两者的影响。 我们的目的是确定添加Ca和烧结曲线对掺pb半导体BaTiO_3的影响,从而为制造PTCR陶瓷产品提供有用的信息。
In this paper, the BaTiO_3-based PTCR semiconductors with pb5mol% and without Ca7mol% were prepared by liquid sintering. The effects of the first sintering temperature on the average grain size of the sample, such as the low temperature resistance, the maximum resistivity and the voltage sensitivity, are discussed. The Ca - doped materials can provide better PTCR performance. Liquid-phase sintering has become a common method for preparing BaTiO_3 semiconductor ceramics. Liquid phase sintering is highly repeatable and the sintering temperature is relatively low, which is important for mass production. There have been numerous reports on the effects of sintering temperature on doping and non-stoichiometry in grain growth and electrical properties . Pure BaTiO_3 with a Curie temperature of 120 ℃ reported the most. In this paper, the experimental results of a material containing pb5mol% instead of the cation Ba and a Curie temperature of 140 ° C have been proposed, and compared with materials containing Ca and 7mol% Ca besides Ca. Calcium is added because it produces a finer microstructure. Sintering process also affects the microstructure. We discuss the effects of adding Ca and sintering curves in terms of average grain size, resistivity at 50 ° C, sudden change in positive temperature coefficient of resistance (PTCR), and voltage sensitivity. Our purpose is to determine the effects of Ca addition and sintering on BaTiO_3 doped pb semiconductors, providing useful information for the manufacture of PTCR ceramic products.