Preparation of spherical AlN powders by combined microemulsion method and carbothermal method

Abstract

Abstract In this study, a two-step strategy for the preparation of micron-sized spherical aluminium nitride (AlN) powder by the combined micro-emulsion method in conjunction with the carbothermal reduction nitridation (CRN) route was designed. The spherical AlN powder with perfect dispersibility was prepared after a heat treatment at 1550 °C for 2 h in flowing N2. The effects of the aluminium fluoride (AlF3) content, reaction temperature and the introduction of yttrium oxide (Y2O3) on the nitridation ratio and on the morphology of granules, in particular, were investigated by XRD analysis and SEM. Additionally, the promotion mechanism of AlF3 and Y2O3 on the nitridation reaction was also discussed. Specifically, one of the underlying formation mechanisms of the spherical granules with the aid of AlF3 and Y2O3, and suggestions on the selection of additives for the CRN synthesis of spherical AlN powder were logically proposed.