Research Of Thick Coating Techniques Of Micro-arc Oxidation Aluminum Alloys

The micro-arc oxidation (MAO) technique is one of the most important key technologies in the surface-treated areas. First, a comprehensive introduction of micro-arc oxidation technology, including the concepts, technical principles, influence factors and preparation methods was described. By using the micro-arc oxidation (MAO) technique, ceramic coatings with high micro-hardness, strong adhesion, high strength, high wear resistance, high temperature shock and electrical insulation properties can be fabricated, which there is no pollution to the environment in the micro-arc oxidation process.In this paper, aluminum alloy micro-arc oxidation ceramic layer was prepared under the different conditions of electricity parameter using DC MAO pulse series equipment. The relationship between the coated ceramic film thickness and current density was investigated. The ceramic coating microstructure and microhardness were also tested. We conducted a comprehensive analysis of the film maximum thickness at the best parameters of current density. The maximum thickness of aluminum ceramic layer was gained under the different conditions of electrolyte formulations by self-made micro-arc oxidation series equipments. The thickness of ceramic coating, the microstructure and microhardness of the ceramic coating were tested, and then comprehensive analysis was performed to select the best solution composition and concentration on the maximum thickness of ceramic coating.The final thickness of as-prepared micro-arc oxidation ceramic coating was up to260μm corresponding to the2A12aluminum alloy. The results showed that electrolyte containing6g/L of Na2SiO3and1g/L of KOH was the most optimal in terms of the hardness and thickness measurements.