上海科技大学知识管理系统

B4C ceramics with different carbon contents were fabricated by pressureless sintering at 2150 °C with SiC as a sintering additive. The effects of carbon content on microstructure, electrical properties and mechanical properties of B4C ceramics were investigated. More carbon content leads to a reduction in grain size and an increase in relative density. With the increase of carbon content, the electrical conductivity of the sample gradually changes from nonlinear to linear because of the formation of a conductive network in the sample. The electrical percolation is obtained when the C content is up to 10 wt%, and the electrical resistivity of the corresponding sample is 56.2 Ω cm. In terms of mechanical properties, flexural strength and elastic modulus shows a slight improvement, fracture toughness remains almost constant while Vickers hardness increases significantly.
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