Micro-arc plasma oxidation technique ( MAPO), also known as plasma electrolytic oxidation (PEO), is an electrochemical surface treatment of the most advanced technology, mainly used in aluminum, magnesium and titanium alloys. Through the electrolytic solution, there is an electrochemical formation of anodic film on the metal surface by spark/arc discharges, which are initiated at potential above the breakdown voltage of the growing oxide film. And the small arc/plasma discharges move rapidly across the anode surface. The instantaneous temperature in micro-arc zone could reach as high as 8000K. The high temperature melting and condensation processes of oxides in aqueous solution will lead to the formation of MAPO coatings with the outer porous layer and inner condense layer. The compact ceramic coatings by MAPO process exhibit unique, intriguing and excellent properties, such as wear resistance, corrosion resistance, high temperature shock, electronic insulation, etc. Aqueous electrolytic solution without strong acid, heavy metals or other toxic substances is an environmentally friendly surface treatment technology.
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| The phenomenum of MAO | Aluminum gear with MAO coatings |