Enhancing Thermoelectric Performance of CrN Ceramics by Optimizing Sintering Temperature

Chromium nitride (CrN) ceramics were sintered at various temperatures by plasma activated sintering, and their thermoelectric properties were explored. The formation of Cr2N phase can be suppressed by venting N2 gas into the chamber before sintering and increasing the sintering temperature to accelerate the densification process. Sintering temperature significantly impacted the thermoelectric properties. Higher sintering temperature led to an increase in the N content, reducing the electrical and thermal conductivity, and increasing the Seebeck coefficient. The single-phased CrN ceramic sintered at 1573K exhibited excellent thermoelectric performance with a maximum power factor of 1002 μW·m-1·K-2, a thermal conductivity of 4.78W·m-1·K-1, and a zT value of 0.20 at 973K. Furthermore, this CrN ceramic also exhibited a high relative density of 97% and a hardness of ~11.9GPa. Enhanced high-temperature thermoelectric properties and excellent mechanical properties make CrN ceramics suitable for thermoelectric applications in extreme environments.