Preparation of Spherical AlN Granules Directly by Carbothermal Reduction–Nitridation Method

In this work, an efficient carbothermal reduction–nitridation strategy was rationally designed and delicately tailored to directly synthesize spherical granules of aluminum nitride. Effects of processing parameters, such as N₂ pressure, additives and temperature on the nitridation ratio, especially on the morphologies of the AlN granules were elaborately investigated. The experimental results showed that the elevated N₂ pressure of 0.9 MPa and additives of CaF₂ and Y₂O₃ greatly favored for forming micrometer‐sized AlN granules with smooth spherical appearance. More significantly, the underlying formation mechanism of spherical morphology and large particle size was also attentively put forward.