Spherical AlN particles synthesized by the carbothermal method: Effects of reaction parameters and growth mechanism

In this work, AlN particles with spherical morphology, smooth appearance and controllable particle size were purposely synthesized through an efficient carbothermal strategy at 1800 °C aiding with the CaF₂ additive. The influences of typical synthesis parameters, such as carbon content, CaF₂ particle size and reaction time on the formation rate, particles size and surface morphology of AlN particles were deeply and comprehensively studied. It was indicated that the intermediate Ca-aluminates was extremely essential to enhance the nitridation rate, promote the AlN growth and form the spherical morphology. More importantly, based on the systematic investigations and intensive analyses, the underlying growth mechanism of spherical AlN particles in the carbothermal process was rationally proposed and elaborated herein.