Effect of Ni doping on the microstructure and electrical properties of Ba–Co–O NTC ceramics

A novel perovskite BaNi_xCo_1‒xO_3‒δ (0 ≤ x ≤ 0.1) Negative Temperature Coefficient thermal ceramic material has been successfully synthesized using a solid-phase method. The XRD analysis revealed that the BaNi_xCo_1‒xO_3‒δ ceramics possess a hexagonal perovskite structure. Moderate doping with Ni ions facilitates high density in this perovskite ceramic material. The grain size exhibits a pattern of initially increasing and then decreasing with the addition of Ni²⁺ doping. The electrical resistivity of the perovskite ceramic material decreases and then increases with Ni²⁺ doping. The electrical conductivity mechanism of perovskite ceramic materials is consistent with the Mott VRH model in the temperature range below 105 K and the thermally activated conduction model in the 105–300 K temperature range. The resistivity, activation energy, and material constant B values of the ceramic material at 125 K range from 50.86–68.09 Ω·cm, 50.45–60.07 meV, and 652.79–687.02 K. A ceramic material with low B value and low resistance was developed for thermal applications, with a measurement temperature range of 10–300 K. The material shows promise for application in the specialized environmental monitoring industry.