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 ballmilling improved the properties of the carbon block. The highest bending strength and micro-hardness of the carbon materials of 124 MPa and 190 Hv were obtained from the calcined sample of the mixture of MCMBs-5 wt.% nano-SiC by ball-milling 48 h. When increasing ball-milling time from 2 h to 48 h, the electric resistivity decreased (the lowest value was 28 mu Omega m) and the d(002) increased. (C) 2011 Elsevier B.V. All rights reserved.