Carbothermal synthesis of spherical AlN granules: Effects of synthesis parameters and Y2O3 additive

In this study, micron-sized spherical AlN granules were delicately synthesized by carbothermal reduction–nitridation (CRN) route with the aid of Y2O3 additive. The effects of synthesis parameters and Y2O3 content on the nitridation rate, particle size and especially on the surface morphology were systematically investigated. The results showed that the reduction and nitridation of intermediate Y-aluminates were extremely significant to promote the formation of micro-sized spherical AlN granules by improving the nitridation rate, increasing the grain size, providing the spherical morphology and promoting the uniform growth of AlN granules. Furthermore, the elevated N2 gas pressure, high reaction temperature also made contribution to the formation of spherical morphology and large particle size. Based on the experimental results, the underlying reaction mechanism in the carbothermal synthesis of spherical AlN granules with Y2O3 was attentively proposed.