| Carbon nanotubes (CNTs) have attracted much attention due to their excellent mechanical, electrical and thermal properties. Of particular interest is the use of CNTs as ideal reinforcement of composites. Three key problems must be solved in the incorporation process of CNTs into metal matrix: the homogenous dispersion of CNTs in metal matrix, the retention of the perfect structure of CNTs, and the strong interfacial bonding between CNTs and matrix. However, these issues are hard to be solved by means of traditional powder mixing process. Therefore, it is very urgent to search a novel method to develop CNTs metal matrix composites.Herein, we report a novel method to in situ synthesize carbon nanoflakes (CNFs), carbon nanospheres (CNSs) and CNTs in Al powders based on solvent thermal reactions in supercritical benzene fluid. The results showed the CNFs, CNSs and CNTs were homogenously dispersed in Al powders.Lamellar structured carbon particles with layer thickness of 300-500 nm were synthesized through a self-assembly process of trichlovinyl benzene in benzene solvent at 300°C. In this process, benzene and hexachloroethane served as carbon sources to form trichlovinyl benzene based on Friedel-Crafts alkylation reaction catalyzed by anhydrous aluminum chloride. Through the introduction of Al powders, CNFs with thickness of 30-50 nm and CNSs with diameter of 50-250 nm were in situ synthesized on the surface of Al powders. It was also found the carbon products were composed of graphitic nanocrystallites and amorphous carbon. Moreover, the ledge growth mechanism of the lamellar structure and the heterogeneous nucleation mechanism of the CNFs and CNSs on Al surface were discussed.Amorphous CNTs with length of 0.2-5μm and diameter of 10-50 nm were in situ synthesized in Al powders based on the dechlorination process of hexachloroethane by using anhydrous ferric chloride as catalyst in benzene solvent at 300°C. A formation mechanism of theα-CNTs in Al powders was proposed.
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