四元取代CaCu3Ti4O12 陶瓷的介电性能及其机理研究OA

To address the problems of high dielectric loss(tanδ),limited temperature stability,and the performance bottleneck associated with single and binary-element substitution in CaCu3Ti4O12 ceramics,a Mg/Zn/Al/Nb quaternary substitution system was constructed.CaCu2.95-xMgxZn0.05Ti3.92(AlNb)0.04O12(x=0.05,0.07,0.09)ceramics were synthesized by the sol-gel method,and the synergistic effects of multi-element substitution on phase structure,microstructure,and dielectric properties were systematically investigated.The results showed that all samples exhibited a cubic perovskite structure without detectable secondary phases,and the doped elements were successfully incorporated into the lattice with stable valence states.Appropriate Mg doping significantly promoted grain growth and improved densification.When x=0.07,the ceramic exhibited the optimal overall performance,achieving a dielectric constant(ε′)of 49397 and a tanδ of 0.024 at 1 kHz,a breakdown electric field of 880 V·cm-1,and capacitance variation within±15％in the temperature range of-55℃ to 125℃.Impedance spectroscopy analysis indicated that this composition exhibited relatively high grain boundary resistance and grain boundary activation energy.X-ray photoelectron spectroscopy results further demonstrated that quaternary substitution increased the contents of Cu+,Ti3+,and oxygen vacancies,thereby enhanced interfacial polarization and increased the grain boundary barrier height,which allowed the simultaneous optimization of high ε′,low tanδ,and satisfactory temperature stability.These findings provide experimental evidence and theoretical insights for the multi-element substitution engineering of perovskite dielectric materials.