Research On Technics And Mechanism Of Micro-Plasma Oxidation On Surface Of Metals

The ceramic coatings on the surface of some metals can improve the shortcomings of low microhardness, poorly corrosion and wear resistance, in the same time maintain the property of the metals. This paper introduces the new surface treatment technology, that is micro plasma oxidation, which can in-situ form the ceramic coatings on the surface of some non-ferrous metals. It breaks out the traditional anode-oxidation technique of forming oxide coating according to Faraday's law, and forms oxide coating in micro plasma areas. It has the characters of simply technique, high efficiency, no pollution, etc.The experimental materials are aluminum and titanium. The influences of the different electrolytic solutions and oxidation time on the ceramic coatings are studied. The properties of the ceramic coatings in different conditions are researched to use this technique in industrial application in the future.The main results show as follows:The experiments of the micro plasma oxidation of aluminum alloy indicate that the ceramic coatings possess smooth surface, high microhardness, better phase structure and property in alkalescent electrolytic solution; The ceramic coating is mainly composed of a-Al2O3 and r-Al2O3. The results of wear-resistance and salt spray test indicate that the wear-resistance and the corrosion-resistance are improved.The experiments of the micro plasma oxidation of titanium alloy indicate that the phase structure of coating is mainly composed of anatase type TiO2 in acidic electrolytic solution. As aqueous pH decreases, the proportion of anatase type TiO2 continually increased. The phase structure of coating is mainly composed of rutile type TiO2 in alkalescent electrolytic solution. As aqueous pH increases, the proportion of rutile type TiO2 continually increase. Different additive can change the structure of the coating and the property of the coating.