Study On Preparation And Properties Of Micro/Nano Particles Reinforced Micro-Arc Oxidation Layer On Aluminum Alloy

The application of aluminum alloy piston in internal combustion engine is significant and in line with the developing trend of engine, however, aluminum alloy has many defects in surface hardness, thermal insulation, wear resistance performance and so on, which restrict its wide application, as a result, aluminum alloy need surface strengthening before application. Ceramic coating with high hardness, heat resistance, abrasion resistance, corrosion resistance and other advantages can be prepared by micro-Arc oxidation technology, making up the inadequacy of aluminum alloy. In addition, micro-Arc oxidation technology can be combined with other technology to prepare better strengthening layer.In this article, micro/nano particles of silicon carbide, serpentine and disulfide were prepared by ball milling, then were mixed according to orthogonal design table and added into the electrolyte to obtain micro/nano particles strengthening layer. The layer was tested by measuring thickness, energy consumption, hardness, roughness and thermal coefficient, and by Friction and wear test. The surface topography and elements contents were tested by SEM. Best mixing program was found by Overall balance method. At last, the reinforcement effect was analyzed by comparing.The result shows that, micro/nano particles can be taken in oxidation layer by adding to electrolyte, the mix program can influence the performance of layer and energy consumption.In the process of micro-Arc oxidation, current size is positively correlated with the growth speed of layer. As the impedance of layer improves with growing, the thickness of layer can be limited by the constant voltage. When the mixing program is silicon carbide 3g/L, serpentine 2g/L, disulfide lg/L, the strengthening effect is the best. Compared with oxidation layer without particles, the strengthening effect of the best sample is:the film thickness increases by 77.81%, the unit energy consumption is reduced by 50.57%, the hardness increases by 30.07%, coefficient of thermal conductivity is reduced by 4.2%. Under the condition of oil lubrication, the wear amount of the best sample is 32.3% that of sample without particles; Under dry friction condition, the wear amount of the best sample is 84% of the latter.