The electrical properties of (Ba, Ca, Ce, Ti, Zr)O3 thermistor for wide-temperature sensor architecture

A series of new negative temperature coefficient (NTC) thermal materials based on (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 (0.00 <= x <= 0.20) ceramics were synthesized by a solid-state method. X-ray diffraction, scanning electron microscope and X-ray photoelectron spectroscopy were used to demonstrate the crystal structure, morphology, and composition of the (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 ceramics, which were composed of solid solution based on the BaTiO3 phase. The average grain size of doped ceramic samples experienced the process of first decreasing and then increasing. The doping of Ce has reduced the sintering temperature. The temperature-dependent resistance analysis revealed that with the change of doping amount x, the thermal constant B-300/1200 (1.21 x 10(4)-1.13 x 10(4) K) and the activation energy E-a300/1200 (0.9777-1.0471eV) was initially increased to maximum values at x = 0.05, followed by the decreasing when x > 0.05. It has been established that the concentration of oxygen vacancies is affected by the transition between Ce4+ and Ce3+ provided by high levels of Ce doping. (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 ceramics exhibited excellent negative temperature characteristics in the range of 300-1200 degrees C. Moreover, the temperature resistance linearity was improved after samples were aged. Hence, the (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 ceramics were regarded as a promising material for high-temperature NTC thermistors in a wide temperature range.

Automated summary

A series of new negative temperature coefficient (NTC) thermal materials based on (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 ceramics were synthesized and their crystal structure, morphology, composition and performance characteristics were investigated. It was found that the average grain size of doped ceramic samples experienced a decrease-then-increase trend, and the doping of Ce reduced the sintering temperature. The thermal constant and activation energy initially increased and then decreased with increasing doping amount, and the concentration of oxygen vacancies was influenced by the transition of Ce ions. The (Ba0.85Ca0.15)(1-x)Ce-x/2(Zr0.1Ti0.9)O-3 ceramics exhibited excellent negative temperature characteristics at high temperatures and showed improved temperature resistance linearity after aging.