Fabrication of Al₂O₃-Ni-CNTs nanocomposites by co-precipitation of CNTs and Ni nanoparticle on Al₂O₃ powder and spark plasma sintering

Carbon nanotubes (CNTs)-dispersed ceramics were usually obtained by simple mixing, or firstly dispersing the metal catalysts inside ceramic powders, and then growing CNTs from the thermal decomposition of hydrocarbon gas. In the present study, a novel route for the fabrication of Al₂O₃-Ni-CNTs nanocomposites was proposed by co-precipitation of CNTs and Ni nanoparticle on Al₂O₃ powder using nickelocene as a precursor in a rotary CVD reactor. Fine Ni nanoparticles (10-50 nm in diameter) and CNTs (20-50 nm in diameter and as long as 1 μm in length) were uniformly dispersed on agitated Al₂O₃ powders. After spark plasma sintering at 1923 K for 0.6 ks, the Al₂O₃-Ni-CNTs nanocomposites showed uniform microstructure and enhanced mechanical properties. Carbon incorporated in nickel changed from amorphous to crystalline phase state after the high temperature treatment. No other impurities were identified, and the incorporation of CNTs and Ni was also found to enhance the relative density and mechanical properties of Al₂O₃. Thus the present method is promising for fabrication of high performance CNTs-ceramic composites.