Synthesis, magnetic and transport properties of oxygen-free CrN ceramics

In the literature, CrN is usually synthetized as thin films and often contains impurities such as oxygen or Cr2N. We successfully prepared pure CrN powder by ammonolysis of anhydrous chromium (III) chloride, which was confirmed by X-ray diffraction analysis (XRD) and SEM-EDS. CrN ceramics were then prepared by classical ceramic route (CCR) and by spark plasma sintering (SPS) at different sintering conditions. Transport properties (Seebeck coefficient, electrical resistivity and thermal conductivity) were measured in the range 2–600 K and the magnetic behavior was examined by SQUID. Above the room temperature thermal conductivity was obtained by laser flash analysis (LFA). Thermal stability and thermodynamic characteristics were probed by simultaneous thermal analysis (STA). Transport properties are strongly affected by the fabrication process and the resulting figure of merit (ZT) is surprisingly high. CrN has big potential as a new high temperature thermoelectric material.