Fluidization Synthesis of Near-Stoichiometric TiN Powder by Locking the Ti/N Ratio in a TiNCl Precursor via Dechlorination

Titanium nitride (TiN) is a versatile ceramic material renowned for its high hardness, excellent electrical conductivity, and plasmonic effects, yet its performance is highly dependent on its stoichiometry ( x in TiN x ). The synthesis of near-stoichiometric TiN powder (0.98 ≤ x ≤ 1.01), which exhibits optimal properties, remains challenging due to a mismatch between mass transfer and reaction kinetics. Herein, we developed a novel fluidized-bed process involving the controlled formation and subsequent dechlorination of a stoichiometric TiNCl coating on seed particles, achieving a final stoichiometry of x = 0.99. The introduction of NH 3 was identified as a critical step for effectively reducing residual chlorine impurity. Furthermore, a self-exfoliation mechanism during the transformation from TiNCl to TiN was revealed. This precursor stoichiometry locking strategy, combined with a fluidized-bed process, not only achieves a 161-fold improvement in dechlorination efficiency over the fixed-bed system but also exhibits a high synthesis rate (∼13 g h −1 in a 30 mm-diameter reactor), demonstrating great promise for the scalable production of near-stoichiometric TiN powder.