Synthesis and property characterization of ternary laminar Zr_(2)SB ceramic

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℃.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 12.46μm in length and 5.12μm in width,and the mean grain sizes of ZrB2 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℃,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·m1/2,and 2166.74±291.34 MPa,respectively.