In-situ reactive synthensis of AlN-SiC composites and solid solutions

AlN-SiC composites and solid solutions were synthesized via the in-situ reactive synthesis. The reactant mixtures in the AlN-Si-C system and Si₃N₄-Al-C system were processed for 1 or 2h at temperatures ranging from 1600 °C to 1900 °C in a nitrogen atmosphere. The effects of different sintering temperatures and soaking times on phase and microstructural characteristics of the product were studied by XRD and SEM/EDS. The results showed that the product synthesized at 1900 °C is a composite of AlN and β-SiC with a small amount of AlN-SiC solid solution for AlN-Si-C system, while a single phase AlN-SiC solid solution could be achieved for Si₃N₄-Al-C system at the same temperature. As soaking time increases, AlN-SiC solid solution decomposes into modulated structures. The formation mechanism of AlN-SiC solid solution was discussed.