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利用金属铁、镍(Fe与Ni保持mol比为22∶78不变)与钛酸钡复合,在保护气氛下成功烧结制备了高介电常数Fe-Ni-BaTiO3复合陶瓷材料,并研究了该复合材料的电导和介电性能及其物理机理.分析结果表明,由于渗流效应,随着陶瓷中金属含量的增加,材料经历了绝缘体—导体突变.同时,在渗流阈值附近,材料的介电常数有了极大的提高.当金属体积含量为0.23时,即在绝缘体向导体转变的渗流阈值附近,复合材料的介电常数达到了22000,为同条件下制备的纯钛酸钡陶瓷体介电常数的12倍,同时材料的介电损耗仍保持为较低值.材料具有明显的Maxwell-Wagner效应特征,这表明传导机理对材料的介电常数的提高起到了很重要的作用.分析了传导机理对介电的影响.
A high dielectric constant Fe-Ni-BaTiO3 composite ceramic material was prepared by metal iron and nickel (the molar ratio of Fe and Ni was maintained at 22:78) and barium titanate were successfully sintered in a protective atmosphere. The results show that due to the seepage effect, with the increase of the metal content in the ceramic, the material undergoes a sudden change in the insulator-conductor. At the same time, near the percolation threshold, the dielectric constant Has been greatly improved.When the metal volume content of 0.23, that is in the insulator to the conductor transition near the percolation threshold, the dielectric constant of the composite reached 22000, prepared for the same conditions pure titanium titanate ceramic dielectric Constant of 12 times, while the dielectric loss of the material remains low.The material has obvious Maxwell-Wagner effect characteristics, indicating that the conduction mechanism of the material to improve the dielectric constant plays a very important role in the analysis of conduction Effect of mechanism on dielectric.