Research On The Effects Of Oxygen On Aluminum Alloy Surface Treatment Coating

Aluminum alloys are widely used in many areas because of a series of excellent properties. However, the development of aluminum alloy is restricted because of some poor performance. So the surface treatment of aluminum alloys becomes the key to expand the scope of using and prolonging service life. Micro-arc oxidation is a new surface treatment technology. A ceramic coating of high hardness, and corrosion resistance can be gotten on the surface of aluminum alloys.The research is based on LY12, this paper makes micro-arc oxidation treatment combined with plasma sintering, raises the high concentration and low ac voltage, injecting oxygen micro-arc oxidation technology, this is able to get compact coatings on the surface of aluminum alloy quickly. We solved the two key questions, one is the processing time is too long, another is the big holes on the surface on the coatings. The paper discusses the influence of oxygen on the coatings mainly. Using SEM and XRD observe the surface morphology of coatings and analysis the phase composition of coatings. Analysis the corrosion resistance of the coating by using polarization curves. The main research contents and results are as follows:Firstly, under the condition of large concentration and low voltage, we study the relationship between process parameters and coatings thickness. We found that the nonlinear relationship between two parameters. But the coating is incompact.Secondly, after we injecting oxygen, we discovered the nonlinear relationship between oxygen and the coating thickness. The coating is compact compared with the coating which is gotten without oxygen.Thirdly, the relationship between coating’s corrosion resistance and coating’s thickness is linear, namely the coating is thicker and its corrosion resistant performance is better. This result suggests that the compact coating plays an important role in improving coating’s corrosion resistance.This study can be prepared compact coating about30microns on the surface of aluminum alloy within15min by micro-arc oxidation. Polarization curve confirms that the coating has good corrosion resistance.