Fabrication and tribological properties of carbon nanotubes reinforced Al composites prepared by pressureless infiltration technique

Aluminum composites reinforced with CNTs were fabricated by pressureless infiltration process and the tribological properties of the composites were investigated. Al has been infiltrated into CNTs–Mg–Al preform by pressureless infiltration in N₂ atmosphere at 800 °C. By means of scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS), it was found that CNTs are well dispersed and embedded in the Al matrix. The friction and wear behaviors of the composite were investigated using a pin-on-disk wear tester under unlubricated condition. The tests were conducted at a sliding speed of 0.1571 m/s under an applied load of 30 N. The experimental results indicated that the friction coefficient of the composite decreased with increasing the volume fraction of CNTs due to the self-lubrication and unique topological structure of CNTs. Within the range of CNTs volume fraction from 0% to 20%, the wear rate of the composite decreased steadily with the increase of CNTs content in the composite. The favorable effects of CNTs on wear resistance are attributed to their excellent mechanical properties, being well dispersed in the composite and the efficiency of the reinforcement of CNTs.