Fabrication and thermosensitive characteristics of BaCoO3−δ ceramics for low temperature negative temperature coefficient thermistor

Abstract

In the present work, BaCoO3−δ ceramic materials were prepared via conventional solid state reaction at different sintering temperatures. The crystal structures, microstructures and electrical properties of BaCoO3−δ ceramics were systematically investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrical measurement. The XRD patterns indicate that the major phases presented in the sintered samples are hexagonal perovskite BaCoO2.6 phase and some other minor phases (BaO or Co3O4). SEM images show that the grain size increases with temperature increasing. The resistivity of the prepared BaCoO3−δ ceramics thermistors decreases exponentially with increasing temperature in each of the range of 12.5–26 and 26–100 K. These prepared materials are intended to be used for NTC thermistors in a temperature range from 12.5 to 100 K.