The effect of gas mixture on the production of AlN and Si3N4 powder using DCRN

Keywords: Aluminum Nitride, Dynamic / Carbothermal Reduction and Nitridation, Aluminum Hydroxide, Silicon Nitride, Powder Production The Carbothermal Reduction and Nitridation (CRN) is among the most used method in the synthesizing of nitride based technical ceramic powders. It is an effective and economical method. The Dynamic Carbothermal Reduction and Nitridation (DCRN) is an optimized version of CRN in which the reaction is realized in a rotating tube furnace. DCRN gives better results in terms of powder quality because of its nature where reactants are in motion during the reaction. In addition to nitride-based ceramics, other technical powders having high-quality, uniaxial, small particle size can also be produced by this method. In this thesis, the production of high purity and high quality AlN and Si3N4 powders starting from low cost raw materials and without using carbon black (or in addition to carbon black) using mixture of reductive gasses or sugar (C6H12O6) as an carbon source was investigated. As a result of the findings, high quality and pure AlN powders were produced using C3H8, N2 and NH3 gas mixture without using solid carbon at 1400 ̊C for 2 hours. Likewise, good results were also obtained in the production of Si3N4 powders using gas mixture instead of solid carbon. Using cheap and readily available SiO2 powders, α-Si3N4 powders were synthesized at 1450 ̊C for 10 and 60 minutes. Products obtained after DCRN processes were analysed using XRD and FESEM.