Fabrication and Characterization of ZrB 2 Ceramic in Presence of Graphite Platelet and SiC

In this research, the influence of graphite platelet (G P ) and its co-reinforced with SiC on the microstructure and flexural strength of ZrB 2 , was investigated. So, ZrB 2 , and ZrB 2 -30 vol% SiC reinforced with 10 and 15 vol% G P were fabricated through spark plasma sintering (SPS) at 1850 ºC for 8 min under a uniaxial pressure of 35 MPa. Full densification was gained in ZrB 2 co-reinforced with G P (in both amounts of 10 and 15 vol%) and SiC. The microstructural evaluation and flexural strength were studied via field emission electron microscopy (FESEM) and three-point bending test. It was found, G P acts as a grain growth inhibitor in ZrB 2 and ZrB 2 -30 vol% SiC and the finest microstructure obtained for ZrB 2 co-reinforced with 10 vol% G P and SiC (3.3 µm). However, a slight increase occurred for ZrB 2 -30 vo l%-15 vol% G P due to some agglomeration introduced in the microstructure. The maximum flexural strengths of ZrB 2 (319 MPa) and ZrB 2 -SiC (445 MPa) were obtained at 10 vol% G P addition. It was determined that synergetic applying SiC and G P has more benefits on the sintering and flexural strength rather than individually. Graphical Abstract