Tribological properties of nano-porous anodic aluminum oxide template

A highly ordered porous alumina template with pores of 45 nm in diameter was synthesized by a two-step electrochemical anodizing process. The influence of pore-enlargement treatment on the porous structure and tribological properties of the film was investigated, and ultrasonic impregnation technology was applied on it to form self-lubricating surface. The structure of the self-lubricating film and its tribological properties were investigated in detail. It can be concluded that the optimum time of pore-enlargement treatment is 20 min. The diameter of the pores and the surface porosity of the film are about 70 nm and 30%, respectively, while the film maintains the property of its high hardness. Under the same friction condition, the frictional coefficient of the self-lubricating film is 0.18, much lower than that of the anodic aluminum oxide template, which is 0.52. In comparison with the lubricating surface of non-porous dense anodic aluminum oxide template, the lubricating surface fabricated by the ultrasonic impregnation method on the porous anodic aluminum oxide template keeps longer period with low friction coefficient. SEM examination shows that some C60 particles have been embedded in the nanoholes of the anodic aluminum oxide template by the ultrasonic impregnation technology.