Reducing atmosphere to manufacture graphene alumina composite

Abstract

The so-called advanced ceramics or engineering ceramics attract various industrial sectors on account of characteristics such as high hardness, biocompatibility, thermal stability, chemical inertia, and corrosion resistance. However, its use ends up being limited by its fragility. The use of carbon allotropes (graphene, nanotubes, and fullerenes) as reinforcement material in ceramics has been widely studied; however, the performance of these allotropes is restricted to specific mixing and sintering conditions. The present work produced a composite material with an Al2O3 (alumina) matrix from commercially available techniques such as conventional sintering and achieved mechanical properties as good as those of composites produced by modern laboratory techniques such as Spark Plasma Sintering. Alumina powders were mixed with multi-layered graphene (MLG) on a ball mill, followed by uniaxial and isostatic pressing and sintered in a reducing atmosphere. The pure alumina ceramic was compared to the alumina-MLG composite, and a 75% increase in microhardness and 40% increase in fracture toughness for the composition with 0.75 wt% of multi-layered graphene was measured. Results showed that alumina-MLG composite can be produced through the conventional mixture and sintering methods, maintaining its properties on par with more modern techniques.