Impact of PTFE particle size in designing BaTiO₃ dielectric composites under the cold sintering process

The Cold Sintering Process (CSP) can provide opportunities to fabricate high-performance BaTiO₃ dielectric composites with polymer materials that are typically difficult to impossible to co-process under a conventional sintering process. Therefore, we investigated the preparation process of BaTiO₃ sintered body by CSP and integrated a well-dispersed intergranular polymer phase. In this study, we focused on preparing BaTiO₃ and Polytetrafluoroethylene (PTFE) composites. We considered the importance of the particle size of the PTFE phase, and correlated the impact on the composite dielectric properties. Through fitting a general-mixing-law to the dielectric properties as a function of volume fraction, we could deduce more homogeneous composites obtained in using the 200 nm PTFE powders. In addition, the temperature dependent dielectric properties and field dependent conductivity of the composites was investigated. It was found that with the good dispersion of the PTFE can suppress the leakage current density in the dielectric composites.