Mechanical properties of pressure-less sintered ZrB2 with molybdenum, iron and carbon additives

ZrB2 powder was successfully densified with Mo, Fe and carbon as sintering aid by pressure-less sintering method. Effects of the above additives were investigated on the densification, microstructure and mechanical properties (hardness, fracture toughness and compressive strength) of sintered samples. It was observed that the ZrB2 samples with 10 wt%Fe and 15 wt%Mo with 1 wt%C had the maximum density. The maximum compressive strength and fracture toughness of 425 MPa and 12.5 MPa m1/2 were obtained for ZrB2–10 wt%Mo–1 wt%C, respectively. Fracture toughness of ZrB2–10 wt%Fe was significantly improved at higher carbon content (2 wt%).