The aligned film of amorphous carbon (a-C) nanorods was prepared by catalytic chemical vapor deposition (CCVD) on an anodic aluminum oxide (AAO) template at 650 8C. The morphology and microstructure of aligned film of amorphous carbon nanorods were examined by scanning electron microscopy (SEM) and Raman scattering spectroscopy. The friction and wear properties of aligned film of amorphous carbon nanorods on the AAO template in vacuum (1.12

Ni-P-Carbon nanotube (CNT) composite coatings as well as Ni-P-SiC and Ni-P-graphite coatings were prepared by electroless plating. The tribological properties of these composite coatings were investigated using a ring-on-block test rig under lubricated condition. The Ni-P-CNT composite coatings exhibited not only high wear resistance but also low friction coefficient compared with the Ni-P-SiC and Ni-P-graphite composite coatings. The favorable effects of CNTs on the tribological properties of the electroless coatings are attributed to improved mechanical properties and unique topological structure of the hollow nanotubes. In addition to preventing the rough contact between the two mating metal surfaces, the shorter CNTs can easily slide or roll within the surfaces of friction pairs. Therefore, the wear rate and friction coefficient of Ni-P-CNT composite coatings can be substantially reduced.

Tribological properties of carbon-nanotube-reinforced copper composites were investigated using a pin-on-disk test rig under dry conditions. The composites containing 4-16 vol% carbon nanotubes (CNTs) were fabricated by a powder-metallurgy technique. The tests were carried out at normal loads between 10 and 50 N, and the effect of volume fraction of CNTs on tribological behavior of the composites was examined. The composites revealed a low coefficient of friction compared with the copper matrix alloy. Due to the effects of the reinforcement and reduced friction, the wear rate of the composites decreased with increasing volume fraction of CNTs at low and intermediate loads. The composites with a high volume fraction of CNTs exhibited high porosity and their wear resistance decreased under high-load conditions.

Ni-P-carbon nanotube (CNT) composite coating and carbon nanotube/copper matrix composites were prepared by electroless plating and powder metallurgy techniques, respectively. The effects of CNTs on the tribological properties of these composites were evaluated. The results demonstrated that the Ni-P-CNT electroless composite coating exhibited higher wear resistance and lower friction coefficient than Ni-P-SiC and Ni-P-graphite composite coatings. After annealing at 673 K for 2 h, the wear resistance of the Ni-P-CNT composite coating was improved. Carbon nanotube/copper matrix composites revealed a lower wear rate and friction coefficient compared with pure copper, and their wear rates and friction coefficients showed a decreasing trend with increasing volume fraction of CNTs within the range from 0 to 12 vol.% due to the effects of the reinforcement and reduced friction of CNTs. The favorable effects of CNTs on the tribological properties are attributed to improved mechanical properties and unique topological struct ure of the hollow nanotubes.

The slurry erosion-corrosion behaviour of TiN coated α-Ti alloy in aqueous silica slurry ontaining 3.5% NaCl has been investigated using a jet-in-slit rig. Erosion- orrosion tests were performed with slurry having jet velocity range 4.8-12.8 m s-1 and at normal impact angle. Because of synergistic effects between erosive wear and flow-induced corrosion, the erosion-corrosion rates of the TiN coating and a-Ti substrate were higher than the sum of erosive wear rates and flow-induced corrosion rates. At the lower slurry velocity, the TiN coating deposited on the a-Ti substrate presented better slurry erosion-corrosion resistance. With increasing slurry velocity, however, perforating, cracking and fragmenting of the hard TiN coating occurred and the protection effect of the coating layer reduced with the erosion-corrosion duration. And then the volume loss of the a-Ti substrate was enhanced through cracking of flakes induced by stress and corrosion.