Effect of heat treatment on performance of high-temperature thermistor LaCrO3

In this study, pure LaCrO 3 ceramic as the negative temperature coefficient (NTC) thermistors were investigated. NTC LaCrO 3 powder with an average particle size of 80 nm was prepared using the sol–gel method, and LaCrO 3 ceramic samples with a relative density spanning from 92.8 to 95.6% were prepared using spark plasma sintering (SPS) at 1450, 1500, and 1600 °C. The LaCrO 3 samples were then heat-treated at 1300 °C in an air atmosphere for 2 h. Before heat treatment, the values of room temperature resistivity were between 1.34 × 10 9 and 2.59 × 10 9 Ω·cm; material constant between 4418 and 4575 K; and activation energy between 0.6099 and 0.6316 eV. After heat treatment, the resistivity was from 2.19 × 10 5 to 1.54 × 10 6 Ω·cm, material constant from 2539 to 2808 K, and activation energy from 0.3505 to 0.3876 eV. This combination of properties renders pure LaCrO3 materials an excellent candidate system for application as NTC thermistors in the high-temperature range of 200–800 °C.