中文摘要：

为了降低CaCu_3Ti_4O_（12）陶瓷的介电损耗,保持高介电常数,采用共沉淀法制备CaCu_3Ti_4O_（12）陶瓷.研究了前驱粉料的热分解过程、煅烧后粉料的物相结构、陶瓷的显微结构和介电性能,并考察了Ca、Cu混合溶液pH值对CaCu_3Ti_4O_（12）陶瓷性能的影响.结果表明：当Ca、Cu混合溶液pH值为5.1时,制备的CaCu_3Ti_4O_（12）陶瓷介电损耗最低,而且能保持高介电常数.在室温下,频率为1kHz时,介电常数为1.4×10~4,介电损耗为0.037.通过对陶瓷性能对比,发现共沉淀反应中各元素的沉淀比例,陶瓷的微观结构和介电性能均受该pH值的影响.因此,Ca、Cu混合溶液的pH值对降低CaCu_3Ti_4O_（12）陶瓷介电损耗、保持高介电常数影响很大.

英文摘要：

In order to reduce the dielectric loss and retain the high dielectric constant,CaCu_3Ti_4O_（12） ceramics were prepared by coprecipitation method.The thermal decomposition process of precursor was studied by TG/DTG and FTIR.The CaCu_3Ti_4O_（12） phase structure was confirmed by X-ray diffraction.The dielectric spectra and I-V characteristics were measured at room temperature.Ca-Cu solutions with different pH values were used.It is found that when the pH value of Ca-Cu solutions is 5.1,the dielectric constant of the CaCu_3Ti_4O_（12） ceramics is still high and dielectric loss reaches the lowest.At room temperature,the dielectric constant is 1.4×l0~4 and the dielectric loss is 0.037,when the frequency is 1kHz.The precipitation of each element,microstructure and dielectric properties of ceramics are affected by the pH value of Ca-Cu solution.Thus the pH value of Ca-Cu solution is one of the key points to decrease dielectric loss and improve dielectric constant of the CaCu_3Ti_4O_（12） ceramics.