Effect of drying methods of Al2O3-GO powder mixture on the properties and microstructure of sintered composites obtained by spark plasma sintering

Abstract

Well-dispersed alumina ceramic-graphene oxide (GO) powder mixtures were fabricated using a colloidal processing route and three drying techniques were applied: in vacuum, spray and freeze dryers. Dense composites were obtained via spark plasma sintering, the technique reducing GO to graphene in situ during the sintering process. The mechanical properties of the sintered composites were investigated. The composites obtained by spray drying have shown the fracture toughness of 4.5 ± 0.4 MPa·m1/2, and hardness of 18.4 ± 0.8 GPa with an extremely high dispersion of graphene within the ceramic matrix.