Nano-composite ceramic coatings were successfully fabricated by micro arc oxidation process in aluminate electrolyte.The compositions,microstructures and phases were investigated carefully.The results indicated that the coatings were a composite structure consisting of many discal micron structures and nano-structures.The average diameter of the discal structure was about 21μm and the central micro-pore size was in the range of 1~10μm.The size of the nano-structures was about in the range of 10~40 nm.The ce...