Preparation of ZrB_2-SiC composites by arc melting and their properties(<Feature>Global Innovation in Advanced Ceramics)

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ZrB_2-SiC composites were prepared by arc melting using ZrB_2 and β-SiC powders as raw materials and their Vickers microhardness, electrical conductivity and thermal conductivity were investigated. The eutectic composition of the ZrB_2-SiC system was ZrB_2-58.5 mol%SiC with a labyrinthine microstructure 100 nm in width and several μm in length. The hardness of the ZrB_2-SiC composites increased with increasing SiC content and showed the highest value of 24 GPa at an indenter load of 4.9 N around the eutectic composition. The ZrB_2-SiC eutectic composite had the highest fracture hardness of 6 MPa m^<1/2>. The electrical conductivity of ZrB_2-SiC composites ranged from 3.2×1O^4 to 5.0×10^6Sm^<-1> at room temperature and decreased with increasing temperature. Their thermal conductivity at room temperature was 70 to 95 W m^<-1> K^<-1> and decreased with increasing temperature. The eutectic composite had the lowest thermal conductivity.
2008-03-01