| Aluminum alloy is the first choice material to lighten the weight of machine parts and components due to its excellent properties such as small density, large reserves, and super ratio of strength, excellent properties and good extrusion processing performance. But some surface properties of the aluminum alloy such as hardness, wear resistance, corrosion resistance are not ideal, so the surface modification of aluminum alloy become an important research direction. At present, aluminum alloy anodic oxidation technology is the most widely used and successful surface modification technology, at the same time, its research and development is most in-depth and comprehensive. Anodic oxide film with its superior performance is also known as a universal protective film of aluminum alloy. As an extension of the ordinary anodic oxidation technology, micro-arc oxidation technology is simple, the film has a very high hardness and good wear resistance, and its physical and chemical properties such as corrosion resistance and electrical insulation also has a qualitative leap than the anodic oxide film. Although micro-arc oxidation technology has many advantages, but at present, the popularization and use of micro-arc oxidation technology are far less than anodic oxidation technology due to its high power consumption and high production limitations caused by high voltage et al. This paper put save energy as a starting point for research.This paper utilized hard anodic oxidation to get pre-film on 6061 aluminum alloy, then, using self-made micro-arc oxidation equipment for surface treatment. By compared the property of micro-arc oxidation films made with different thickness to get the best pre-film thickness was 10 ?m. The effect of micro-arc oxidation process of aluminum alloy with pre-film was studied under the condition of constant current. The influence of the growth mechanism of micro-arc oxidation films was discussed and the phases, performance and energy consumption of micro-arc oxidation was analysis.The results show that the existence of the pre-film shortened the arcing time of micro-arc oxidation, promoted the growth of voltage in the early stage of micro-arc oxidation, improved the stability of the voltage value, shortened the stage of no-spark and promoted the white sparks turned into orange sparks which speed up the evolution process if micro-arc oxidation sparks.Through discussion, the generation of spark comes from the breakdown of the gas by high voltage, the discharge area of the sample spreading along with pre-film layer and the point discharge effect was obvious. A series of electrochemical, physical and chemical reaction happened with spark discharge. In the process of discharge, spark and energy willcontact with discharge channel, solution and matrix metals. These parts under high temperature will happened volume shrinkage, phase transition and solute deposition to realize the growth of the film. The process of dissolved and generated occurred simultaneously.Micro-arc oxidation treatment with the same time on pre-film and no-pre-film samples, found the thickness, friction performance and corrosion resistance of pre-film sample was better than no-pre-film sample, but the energy consumption of pre-film increased slightly. Compared the MAO films with the same thickness on pre-film and no-pre-film samples, found no-pre-film sample performance was slightly better than pre-film sample, but the energy consumption of no-pre-film sample was two or more times than pre-film sample. Therefore, pre-film can effectively reduce the energy consumption. |
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