Greatly enhanced permittivity in BaTiO3-epoxy dielectric composites with improved connectivity of ceramic phase

Abstract

BaTiO3-epoxy dielectric composites were prepared by curing the liquid epoxy monomer that infiltrated into the partially-sintered BaTiO3 porous ceramics. The BaTiO3 volume fraction of the composites maintained around 58.6% with increasing the sintering temperature from 600 °C to 1000 °C, while the significant microstructure evolution, improved connectivity of BaTiO3 phase and dramatical increase in permittivity from 102 to 697 were observed. The permittivity and BaTiO3 volume fraction further increased to 2328 and 83.5% for the sintering temperature of 1250 °C. The present composites had the permittivity 1–2 orders of magnitude higher than the 0–3 type ones, and the extraordinary results were mainly attributed to the improved connectivity of BaTiO3 phase that benefited from partial sintering. The connectivity also had a significant effect on the temperature dependence of permittivity, and good combination of temperature-stable high permittivity, low dielectric loss and relatively low ceramic fraction could be obtained by regulating the connectivity of BaTiO3 ceramic phase.

Keywords

• Ceramic-polymer composite
• Connectivity
• High permittivity