▎ 摘　　要

Since its discovery, graphene has attracted worldwide attention in the scientific community owing to its unique combination of properties. Thus, graphene is an ideal second phase to improve the structure and properties of metal, ceramic and polymer composite materials. This work presents a comparative study of two types of alumina-graphene composites fabricated with two sizes of delta-Al2O3 powders, nanometer and submicrometer, reinforced by graphene nanoplatelets (GNPs) and consolidated with the spark plasma sintering technique. The microstructure, mechanical and tribological properties of Al2O3-GNPs composites are influenced by the grain size of the ceramic matrix. Hardness values improve notably. The maximum value reached was 27.4 GPa for a composite fabricated with nanometric alumina powders, which is about 27 % higher than that of the Al2O3 monolithic material. Also, the methodology of powder mixing has a fundamental importance in obtaining materials with high-level properties.