Borosilicate glass matrix composites containing multi-wall carbon nanotubes

Carbon nanotubes (CNTs) are in the range of the most promising reinforcing materials for structural composites, since they possess extraordinary Young's modulus and mechanical strength. In this study, multi-wall CNTs are considered for the first time as reinforcing elements in a borosilicate glass matrix. The densification behaviour and the microstructure characterisation of composites containing 10 wt.% multi-wall CNTs are presented. The coating of CNTs with silica by a sol-gel process is effective in promoting the homogenisation and the densification of the CNTs/glass powder mixtures. Cold pressing and pressureless sintering or hot pressing at moderate temperatures were employed to fabricate the composites. Pressureless sintering did not lead to well densified composites. The compaction degree achieved by hot pressing (85% theoretical density), on the contrary, is found to be promising for the development of structural composites, although optimisation of the hot-pressing parameters is required to achieve higher densities.