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Abstract: SiC whiskers (SiCw) was prepared and SiCw-B4C–Si composites were fabricated by ball milling together with reactive hot press sintering process at the temperature around 1850K and 30MPa. The compositions, morphologies and mechanical properties of the fabricated composites were investigated. The hardness was decreased with the addition of SiCw and Si. The Si additive improved the relative density of B4C, whereas the addition of SiCw did not change the density to much. The addition of SiCw and Si reinforced the composite in fracture toughness and flexural strength due to the formation of laminated flakes and fiber network structures. At the contents of 5wt% SiCw and 10wt% Si, the relative density, hardness, flexural strength and fracture toughness of the composites could reach 96.5%, HRA93.5, 487MPa, 5.78MPam1/2, respectively. [Copyright &y& Elsevier]

ZrB 2 powders were successfully prepared via carbothermal reduction of ZrO 2 with H 3 BO 3 and carbon black under flowing argon. By introducing SiC species into reaction mixtures, the effects of SiC addition on phase composition and morphology of ZrB 2 powders thermally treated at different temperatures were investigated. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). The highly pure ZrB 2 with the mean size of 5 µm could be obtained at 1600 °C for 90 min and the grains presented columnar shapes. After addition of SiC, ZrB 2 revealed relatively better crystallinity and finer particle size. Regular columnar ZrB 2 grains ranging from 1 to 2 µm were seen existing after reaction at 1500 °C for 90 min. [ABSTRACT FROM AUTHOR]