Preparation And Tribological Properties Of Hydrophobic Films On Aluminum Substrates

Nowadays, tribological performance of aluminum alloys had attracted a wide rangeof vision, as they are widely used in industrial. There are several ways to reduce frictionof aluminum in sliding contact. One way is to construct surface texture on the smoothsurface, in which texture can effectively reduce the friction by decreasing actual contactarea, and thus significantly improve the tribological properties of contact pair. Anotherway is to using self-assembly technology and sol-gel one. The main research content ofthis thesis is to firstly construct the surface texture on aluminum surface by usingchemical etching technology, and then coated textured surface by using sol-gel andself-assembly technology. We systematically study the formation mechanism of theinorganic-organic hybrid film, its surface morphology and wettability, with emphasizedon the tribological properties of the film. We also discuss the preparation conditions onthe wetting and tribological performance of films. The main results are as follows.（1） After aluminum were etched by NaOH solution and then coated by a film ofstearic acid, the contact angle of water of film is as large as140°, showing a highhydrophobicity. The hydrophobic film could effectively protect the aluminum substrate.（2） Al₂O₃or TiO₂films were deposited on the aluminum, then coated by a film ofstearic acid. The film shows high hydrophobicity. Under load of0.5N, the wear life offilm could as long as2200s, showing good anti-friction and wear-resisting performance.（3）The sol-gel-derived Al₂O₃film on aluminum was treated by hydrazine hydratesolution and then deposited by film of stearic acid. The film obtained shows the contactangle as large as150°, and also present excellent antifriction and wear-resistingproperties.