Effect of the graphene sheets incorporation on physicochemical properties of nano-alumina

The colloidal processing method was suggested for obtaining of chemically homogeneous composite powder based on graphene and nano-alumina. The method allows integrating a hybrid structure by mixing components at nanoscale owing to use exfoliated oxygen-free graphene sheets and as-prepared Al-containing sol. This method leads to the production of a superfinely dispersed alumina in the composite and to avoid agglomeration of graphene in the bulk material. It turned out that the graphene sheets partially protect the alumina crystallites from deformation and phase transition in a temperature region of 1130°С, which is critical for pure nano-alumina. The content of graphene sheets even less than 2 wt.% leads to a decrease in compressibility of composite compared to pure alumina. The elasticity of the obtained sintered material is increased, which makes it promising for the development of fine-grained ceramics with improved mechanical properties, such as hardness, impact strength and fracture strength. The achieved improvements in the structure and features of the graphene-alumina composite as well as dilatometric properties are very demand in the production of medical materials with high biocompatibility, sensors, materials with low electrical resistance, catalysts, adsorbents, Li-battery electrodes.