EFFECTS OF ELECTRICAL PARAMETERS ON TITANIA FILM GROWN BY MICRO ARC OXIDATION

The effects of electrical parameters including applied voltages, duty cycles, and frequencies, on the structures of titania film by micro arc oxidation (MAO) technology were studied. Micro arc oxidation was conducted for Ti with pulsed dc power supply. The voltage was controlled at various constant applied voltages (200, 230, 270 V) with various pulse frequencies (dc, 20, 30, 40, 50 kHz) for 3 minutes, and the pulse current was measured with time. There seems to be a minimum absolute duty period (26 mu s) in order to allow oxide thickness to grow, because with a duty period lower than 26 mu s, the oxide may stop growing. In other words, with less than 26 mu s, it is hard for Ti ions to diffuse through the oxide film to grow to a certain thickness.