Fabrication of CaCu3Ti4O12 Multilayer Capacitors, Their Microstructure and Dielectric Properties

Abstract

The high-permittivity material CaCu3Ti4O12, being a naturally formed internal barrier layer capacitor, was utilized for preparation of slurries for tape casting and fabrication of multilayer ceramic capacitors. The dielectric properties of capacitors were studied in a wide frequency range of 0.1 Hz – 2 MHz and in the temperature range from −55 to 400°C. The dominant response recorded at low frequency range and at temperatures above 150°C was assigned to grain boundaries. The dielectric response at low temperatures and/or high frequencies was attributed to grains. SEM and EDS studies showed heterogeneous microstructure and composition of ceramic layers. The fabricated multilayer capacitors exhibit low sintering temperature, good compatibility of ceramic layers with the applied commercial conductive pastes, high specific capacitance and a relatively low temperature coefficient of capacitance.