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

Abstract

An approach for the production of homogenous Al2O3–5SiC-1CNTs hybrid nanocomposite via molecular level mixing is reported. Aluminum nitrate nonahydrate, dimethylformamide, SiCβ 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 4h 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.