Synthesis and Property Characterization of Ternary Laminar Zr2SB Ceramic

In this paper, Zr2SB ceramics with high relative density (99.03%) and high purity of 82.95 wt% (containing 8.96 wt% ZrB2 and 8.09 wt% zirconium) were successfully synthesized from ZrH2, sublimated sulfur and boron powder by spark plasma sintering at 1300 ℃. The reaction mechanism, microstructures, physical properties and mechanical properties of Zr2SB ceramic were systematically studied. The results show that Zr2SB was obtained by the reaction of zirconium sulfide, zirconium and boron, and ZrB2 coexisted in the sample as a symbiotic impurity phase. The average grain size of Zr2SB was 12.46 μm in length and 5.12 μm in width, and the mean grain sizes of ZrB2 and zirconium impurities were about 300 nm. In terms of physical properties, the measured thermal expansion coefficient was 7.64 × 10-6 K-1 from room temperature to 1200 ℃, and the thermal capacity and thermal conductivity at room temperature were 0.39 J·g−1·K−1 and 12.01 W∙m−1∙K−1, respectively. The room temperature electrical conductivity of Zr2SB ceramic was measured to be 1.74 × 106 Ω−1∙m−1. In terms of mechanical properties, Vickers hardness was 9.86 ± 0.63 GPa under 200 N load, and the measured flexural strength, fracture toughness and compressive strength were 269 ± 12.7 MPa, 3.94 ± 0.63 MPa·m1/2, and 2166.74 ± 291.34 MPa, respectively.