Micro Arc Oxidation Technology for Aluminum and Aluminum Alloys
Micro-Arc Oxidation (MAO) is a surface modification technology developed in 1982. It was first discovered in the coating of magnesium alloys. Through the micro-arc oxidation technique, a ceramic coating is formed on the surface of an aluminum or aluminum alloy workpiece. MAO technology can form a ceramic protective film on the surface of the substrate, improve the corrosion resistance and wear resistance of the substrate, and change the surface properties such as surface color of the substrate.
MAO technology utilizes an electric arc to generate high temperature between the active electrode and the aluminum or aluminum alloy substrate. Alkaline solution containing oxidant is used as an electrolytic solution. The heat generated by the arc gasifies some of the components in the alkaline solution and forms an oxide film on the surface of the workpiece. Depending on the composition of the electrolyte and the processing parameters, MAO can create a micro-porous ceramic film that combines corrosion and abrasion resistance with high cost-efficiency.
MAO technology offers a simple and economical way for improving the performance of aluminum and aluminum alloy components. MAO ceramics have excellent corrosion resistance, abrasion resistance, shock resistance and excellent insulation and electrical insulation properties. MAO technology enables the combination of several coatings layers on the surface of the substrate to achieve improved surface performance, extends the service life of aluminum and aluminum alloy workpieces or components, and at the same time reduces the cost of maintenance. MAO technology has been widely used in many industries such as automobile, aerospace, communication, military and other related industries.
MAO technology is suitable for all kinds of aluminum and aluminum alloys, the most important parameters for MAO process is the process temperature, the current configuration and electrolytic solution specification. In general, the higher the process temperature and the higher the current density, the better the coating adhesion, the thicker coating thickness and the better corrosion resistance of the workpiece. Therefore, the configuration of the current system and the selection of the electrolyte are very important in MAO process.
MAO technology has several advantages compared to other thermal spraying or electroplating methods. Compared to these processes, MAO technology is simpler and easier to operate, and can maintain relatively low temperatures compared to other methods. MAO technology is also environmentally friendly, as it does not require the use of hazardous chemicals such as acid or base. As MAO technology is less abrasive and is suitable for small parts and workpieces, it can reduce the post-processing time and cost and improve the environmental impact of the manufacturing process.
In conclusion, MAO technology is an effective and efficient process for improving the performance of aluminum and aluminum alloy components. With its advantages, MAO technology has been increasingly used to surface engineering in the world. While MAO technology brings several benefits and advantages to industry, the selection of the correct process parameters and control of process conditions are critical for achieving high quality coatings and surfaces with improved performance.
