Research On Functional Ceramic Coatings Formed By Micro-Arc Oxidation

Microarc oxidation, also called anodic oxidation or plasma enhanced electrochemical surface ceramic coating technology, is a novel technique to prepare metallurgical bonded ceramics on valve metals. Plenty of researches have been done on Microarc oxidation over the recent years; however, most of them were focused on the performance evaluation and testing aspects of Microarc oxidation coatings.Time-varying changes on factors, such as electric parameter, coating thickness, surface roughness, coating composition and microstructure during the Microarc oxidation process, were fully investigated and mentioned at the growth characteristic part of the research in order to better understand the growth character of Microarc oxidation ceramic coatings. On the other hand, the protection and invalidation mechanism of the Microarc oxidation ceramic coatings were also approved by electrochemical methods. The results show that species from the electrolyte also take part in the Microarc oxidation process. Different species have their own transportation model. By analyzing the evolution and characterization of the Microarc oxidation ceramic coatings, the whole growth process can be concluded as a combined action of the electrochemical or chemical dissolution effect on the surface, the plasma chemical reaction in the discharge channels and the implant process of high energy density plasma at the end of discharge channels, as well as the mechanical peeling damage caused by the violent energy input at some partial areas.