Synthesis and property characterization of ternary laminar Zr2SB ceramic

Abstract In this paper, Zr ₂ SB ceramic with purity of 82.95 wt% (containing 8.96 wt% ZrB ₂ and 8.09 wt% zirconium) and high relative density (99.03%) was successfully synthesized from ZrH ₂ , sublimated sulfur, and boron powders by spark plasma sintering (SPS) at 1300 °C. The reaction process, microstructure, and physical and mechanical properties of Zr ₂ SB ceramic were systematically studied. The results show that the optimum molar ratio to synthesize Zr ₂ SB is n (ZrH ₂ ): n (S): n (B) = 1.4:1.6:0.7. The average grain size of Zr ₂ SB is 12.46 µm in length and 5.12 µm in width, and the mean grain sizes of ZrB ₂ and zirconium impurities are about 300 nm. In terms of physical properties, the measured thermal expansion coefficient (TEC) is 7.64×10 ⁻⁶ K ⁻¹ from room temperature to 1200 °C, and the thermal capacity and thermal conductivity at room temperature are 0.39 J·g ⁻¹ ·K ⁻¹ and 12.01 W·m ⁻¹ ·K ⁻¹ , respectively. The room temperature electrical conductivity of Zr ₂ SB ceramic is measured to be 1.74×10 ⁶ Ω ⁻¹ ·m ⁻¹ . In terms of mechanical properties, Vickers hardness is 9.86±0.63 GPa under 200 N load, and the measured flexural strength, fracture toughness, and compressive strength are 269±12.7 MPa, 3.94±0.63 MPa·m ^1/2 , and 2166.74±291.34 MPa, respectively.