Spark plasma sintering of graphene platelet reinforced zirconia composites with improved mechanical performance

In this study graphene platelet (GPL)-reinforced yittria stabilised zirconia (YSZ) composites were fabricated using a spark plasma sintering furnace to evaluate a new type of structural material for engineering applications. The effects of the content of GPLs on the microstructures and mechanical performances of the GPL/YSZ ceramic composites were investigated. It is found that GPLs are well dispersed in the YSZ matrix and GPL/YSZ composites are nearly fully consolidated. The addition of GPLs significantly refines the ceramic matrix and a higher percentage of GPLs lead to a finer microstructure. GPLs retain their structural integrity during the high temperature processing and phase transformation of YSZ from the tetragonal to monoclinic occurs with the presence of GPLs. Both hardness and toughness of the YSZ matrix are improved by adding GPLs. A maximum improvement of around 7% and 60% in hardness and toughness are achieved respectively.