The Synthesis Of CNTs Reinforced Aluminum Matrix Composites By In-situ And Their Resistance To Wear And Corrosion

Carbon nanotubes (CNTs) reinforced aluminum matrix composites have taken great attentions for their promising physical and mechanical performances. The investigations about preparation technology, tribology and corrosion behaviour of CNTs/Al composites would take a great impact on theory and application for the preparation technology of nano-phase reinforced metal matrix composites. In this paper, CNTs/Al composites were fabricated by a new methed called"in-situ chemical route", and the effect of CNTs on the microstructure, hardness, tribology and corrosion behaviour of the composites were investigated.CNTs/Al composite powder was fabricated by an in-situ chemical route. The catalyst Ni/Al was obtained by"co-precipitation"using aluminum as carrier. Then, CNTs/Al composite powder was produced by the process of chemical vapor deposition (CVD) form Ni/Al catalyst using methane as a carbon source and N2 and H2 as carried gases. The results showed that CNTs synthesized by the in-situ chemical route uniformly distributed in aluminum matrix. The CNTs yield was increased with the content of Ni in Ni/Al catalyst and reaction time increasing. The yield and the morphology of CNTs varied depending on the ratio of N2 and H2. Moreover, the growth of CNTs could be restrained by H2, while the N2 had opposite effects on the growth of CNTs. N2 could restrain CNTs to grow by grabing the adsorption point of carbon atoms on the surface of cacalyst, and also could promote CNTs to grow by accelerating the diffusion of carbon atoms in Ni particles.CNTs/Al composite bulks were obtained using powder metallurgy method with as-previous CNTs/Al composite powder. The analysis of the microstructure and hardness of CNTs/Al composite demonstrated that the grains of aluminum were refined and the hardness of composite was increased with the content of CNTs in composites increasing.The friction and wear properties of CNTs/Al composites were studied by oil wear process. The results showed that the friction and wear performance of composite was improved with CNTs as the reinforcement. A low-temperature annealing treatment could improve the friction and wear performance of the composites at low load, and the opposite result at high load.The corrosion behavior of CNTs/Al composite was investigated using electrochemical method and compared with LC4CS and pure aluminum. The results showed that CNTs had the opposite influences on the corrosion behavior within the composite. On one hand, as the second-phase, CNTs would cause the galvanic couple. On the other hand, CNTs could limit the development of the corrosion because of its good resisting corrosion property and homogeneous distribution in composite.