The influence of ball-milling on improving the performance of mesocarbon microbeads based carbon blocks

High density and high strength carbon blocks were prepared from mesocarbon microbeads (MCMBs) by ball-milling pre-treatment and doping with nano-SiC. Ball-milling pre-treatment destroyed the spherical shape and reduced the grain size of MCMBs, inhibiting the voids or cracks formation in the neck regions of the samples during sintering process. Meanwhile, nano-SiC played a catalytic graphitization effect and the doped raw materials with very small particle size and homogeneous distribution after ball-milling improved the properties of the carbon block. The highest bending strength and micro-hardness of the carbon materials of 124MPa and 190Hv were obtained from the calcined sample of the mixture of MCMBs-5wt.% nano-SiC by ball-milling 48h. When increasing ball-milling time from 2h to 48h, the electric resistivity decreased (the lowest value was 28μΩm) and the d₀₀₂ increased.