| With strong light, electrical conductivity, thermal conductivity and easy recycling advantages, aluminum alloy is widely used in the aerospace, transportation, light industry,building materials and electronic communications. However, due to the low hardness,mechanical components made with aluminum alloy tend to have higher friction coefficient with violently abrasion. Oxidizing treatment is used obtain anodic alumina membrane, can make the aluminum alloy has a higher surface hardness and good wear resistance. As an important research direction in surface engineering, anodizing has very extensive application in the industry. But the friction coefficient of anodic alumina membrane is very high. In order to make the anodic alumina membrane can obtain better tribological performance, In this paper, combined the technology of solid lubrication, filling soft metal solid lubricant in anodic alumina membrane pore,manufacture the composite anodic alumina membrane with self-lubricating properties.To make aperture large alumina membrane to guarantee the physical properties and realize the filling of lubricating materials. also oxalic acid and phosphoric acid were chosen as electrolyte, and DC constant power was chose as power supply, furthermore, the preparation was made under outside circulation cooling system. The influence of oxidation current density and time change to the growth speed, the surface topography and hardness alumina membrane are carefully researched.According to the diode theory of alumina membrane resistance layer, the resistance properties of untreated alumina membrane resistance layer is not conducive to promote the direct current (DC) deposits. To fulfill the requirement of electrical resistance of the alumina membrane barrier layer, the (NH4)2SiF6 is added together with the ladder step-down method at the end of the anodic oxidation,and by this way, the resistance of the barrier layer of the modified alumina membrane is reduced. At the same time, the impacts of modified process to the influence of oxidation, surface morphology and hardness resistance performance is investigated.The modified anode alumina membrane which deposited copper nanowires and copper nanowires - nano graphite in the hole of alumina was obtained by DC deposition technology.The factors which affected the preparation of composite alumina film like keep voltage(ladder after antihypertensive treatment retention voltage are studied and the best process parameter combination was searched by control variable method. The tissue morphology and structure of alumina membrane were studied by SEM and XRD, and the growth pattern of copper nanowires and copper nanowires-nanometer graphite are analyzed and certified.According to the analysis of mechanical properties tested by Micro hardness tester and binding force tester, the binding force is in the substrate and organize uniform deposition film layer of copper nanowires and copper nanowires - nanometer graphite.Finally, sedimentary voltage, the influences of graphite content load and friction force to friction coefficient, wear volume and the influence of grinding crack morphology are analyzed with the dry friction tests on prepared compound aluminum oxide membrane. With the comparison to friction and wear of alumina alloy and alumina membrane, friction and wear mechanism of composite oxide film are analyzed. According to the analysis results, the alumina film of copper nanowires and nanometer graphite composite co-deposition show a lower friction coefficient and strong wear resistance performance. The wall of porous anodic alumina membrane hole and the filling copper nanowires are orderly arranged in the nanostructure to improve the wear resistance of alumina membrane. The filling nanowire and nano graphite form the plastic sliding lubrication layer on the surface of composite alumina film in the process of friction, and by this pattern, composite alumina film has lower friction. |
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