Effect of TiN content on properties of NiFe ₂ O ₄ ‐based ceramic inert anode for aluminum electrolysis

Abstract NiFe ₂ O ₄ ‐based ceramic inert anodes for aluminum electrolysis doped with various TiN nanoparticles were prepared by a two‐step cold‐pressing sintering process to investigate how TiN affected the sintering behavior and properties of the composites. The differential scanning calorimetry‐thermogravimetry (DSC‐TG), X‐ray diffraction (XRD), and microstructure analysis results indicated that the Ti and N were evenly distributed in the NiFe ₂ O ₄ matrix to form a solid solution. The maximum linear shrinkage and linear shrinkage rate were enhanced with the increase of TiN nanoparticles contents, and the sintering activation energy of initial stage was lowered from 382.63 to 279.58 kJ mol ⁻¹ with the TiN nanoparticles additive range from 0 to 9 wt%. When the content of TiN nanoparticles was 7 wt%, the relative density, bending strength, and elastic modulus reached their maximum values of 97.24%, 73.88 MPa, and 3.77 GPa, respectively, whereas the minimum static corrosion rate of NiFe ₂ O ₄ ‐based ceramic of 0.00114 g cm ⁻² h ⁻¹ was obtained, mainly attributed to the relatively dense and stable microstructure. The electrical conductivity of NiFe ₂ O ₄ ‐based ceramics presented a clear ascending trend with increasing TiN nanoparticles content and elevated temperature, attributed to the increased concentration and migration rate of carrier.