Magnesium Alloy Surface Micro-arc Oxidation Process

Research actuality, application foreground and field of MAO(Micro Arc Oxidation) technology are reviewed on the base of studying lots of literature at home and abroad. The basic knowledge of MAO is also genergised.The experiment research is an important part. In this part, the formulates of phosphate, silicate and aluminate system have been optimized. The current destiny Oxidation time current frequency occupy-empty ratio of current influence formation of ceramic coating on the surface of magnesium alloy by MAO are also studied . The condition of forming excellent ceramic coating is found through lots of experiments. The mechanism of forming ceramic coating on magnesium alloy is discussed. Morphology, structure of ceramic coating is observed by SEM. The phase constitute of ceramic coating is measured by XRD. The thickness, corrosion resistance of ceramic coating fabricated in different conditions is tested and analyzed.Experiment results show that the ceramic coating of magnesium alloy is made up of loose coating, compact coating and transition coating. The parameters as oxidation time, current destinyi occupy-empty ratio of current, current frequency, electrolyte constitutes have obvious influence on the quality and corrosion resistance of ceramic coating. It is founded that compactness is the key factor to influence the corrosion resistance from the observation of structure. Current destiny and output voltage are two key factors of MAO. Length of oxidation time is one of fundamental factors of MAO ceramic coating thickness in certain range of time. Electrolyte solution component has a little influence, But it is not important.The raicroarc oxidation ceramic coating is mostly made up of MgO, Al2O3, MgAl2O4 and amorphism phase.Because ceramic coating can be formed on the surface of magnesium alloy surface by MAO. The merit of ceramic materials and magnesium alloy is combined by MAO technology. MAO technology can meet lots of require of high technology. It has extensively application foreground in many fields. For example, war industry, aviation, spaceflight, machine, waeve, automobile, medical treatment, electron and ornament field etal.