Characterization of Al W oxide coatings on aluminum formed by pulsed direct current plasma electrolytic oxidation at ultra-low duty cycles

The growth of thin oxide coatings on the aluminum substrate in water-based sodium tungstate electrolyte by plasma electrolytic oxidation (PEO) is discussed and experimentally illustrated. carried out using a distinctive ultra-low duty cycle pulsed direct current (DC) power supply. During PEO processing elements present micro-discharges are identified standard optical emission spectroscopy (OES) technique. spectral line shape analysis first two hydrogen Balmer lines shows presence types micro-discharges. Obtained also characterized with respect to their morphology chemical phase composition. It shown that composed Al, O, W, featuring low roughness porosity. Partial crystallization resulted identification WO3, W3O8, gamma-Al2O3 crystalline phases.