Reducing the low-frequency dielectric loss of CaCu_3Ti_4O_(12) ceramics by adding (In_(0.5)Nb_(0.5))_(0.05)Ti_(0.95)O_2

摘要

CaCu_3Ti_4O_(12) (CCTO) is a very promising high dielectric permittivity ceramic, but the larger low-frequency dielectric loss limits its application. According to internal barrier layer capacitance effect, which is commonly accepted to explain the unusual dielectric properties of CCTO ceramic in the kHz frequency range, constructing insulating phase boundaries between CCTO grains is an effective method to reduce the low-frequency dielectric loss. Therefore, (In_(0.5)Nb_(0.5))_(0.05)Ti_(0.95)O_2 (INTO) ceramic powder, another high dielectric permittivity ceramic with much higher sintering temperature than CCTO, was added to CCTO ceramic powder to prepare CCTO/xINTO multiphase ceramics with the structure of INTO phase separating CCTO phase. The experimental results show that CCTO/xINTO multiphase ceramics with the designed structure have been obtained, and their low-frequency dielectric loss indeed decreases significantly compared with CCTO ceramic, which should be mainly attributed to the insulating INTO phase. The CCTO/INTO ceramic sintered at 1040 °C for 8 h in atmosphere exhibits good overall dielectric properties at room temperature, of which the low-frequency dielectric loss is less than 0.05 and the dielectric permittivity reaches 3000.