Molecular level mixing: An approach for synthesis of homogenous hybrid ceramic nanocomposite powders

An approach for the production of homogenous Al₂O₃-5SiC-1CNTs hybrid nanocomposite via molecular level mixing is reported. Aluminum nitrate nonahydrate, dimethylformamide, SiC_β nanoparticles, and functionalized CNTs were magnetically stirred and sonicated to prepare the desired slurry. Heating of the dried mixture in normal atmosphere at 400°C for 4 h resulted in the formation of amorphous Al₂O₃ matrix, imbedded with CNTs and SiC nanoparticles, which crystallized during subsequent sintering. FT-IR was used to characterize bonds formed during powder synthesis. The uniform distribution of CNTs and SiC in the synthesized powder and consolidated sample was ascertained using x-ray mapping, FE-SEM, and TEM. Dense alumina and homogeneous Al₂O₃-5SiC-1CNT nanocomposite were consolidated by spark plasma sintering at 1500°C for 10min. The composite possessed improved fracture toughness (by ~33%) and slightly reduced hardness (by ~4%) with respect to monolithic Al₂O₃.