caa a22 4500 463225716 CHVBK 20180405153226.0 cr unu---uuuuu 170326e20071101xx s 000 0 eng 10.1007/s10853-007-1842-0 doi (NATIONALLICENCE)springer-10.1007/s10853-007-1842-0 Effects of duty ratio at high frequency on growth mechanism of micro-plasma oxidation ceramic coatings on Ti alloy [Elektronische Daten] [Zhongping Yao, Yanli Jiang, Zhaohua Jiang, Fuping Wang] The aim of this work is to study the effects of duty ratio on the growth mechanism of the ceramic coatings on Ti-6Al-4V alloy prepared by pulsed single-polar MPO at 2,000Hz in NaAlO2 solution. The phase composition of the coatings was studied by X-ray diffraction, and the morphology and the element distribution in the coating were examined through scanning electron microscopy and energy dispersive spectroscopy. The thickness of the coatings was measured by eddy current coating thickness gauge. The corrosion resistance of the coated samples was examined by linear sweep voltammetry technique in 3.5% NaCl solution. Duty ratio influenced the composition and structure of the coatings. Many residual discharging channels on the coating surface showed that the spark discharge at 2,000Hz was mainly attributable to the breakdown of the oxide film, which was suitable for the elements both from the electrolyte and from the substrate to join MPO process, and therefore, the coating was mainly composed of Al2TiO5. Because of the increase of the congregation and the adsorption of Al from the electrolyte with increasing duty ratio, the redundant Al on the electrode surface led to the formation of γ-Al2O3. And Al and Ti in the coating existed in the form of the reverse gradient distribution. Meantime, ceramic coatings improved the corrosion resistance of Ti alloy, and the coating surface morphology and thickness determined the coated samples prepared at D=20% had the best corrosion resistance among the coated samples. Springer Science+Business Media, LLC, 2007 Yao Zhongping School of Materials Science and Engineering, Harbin Institute of Technology, 150001, Harbin, PR China aut Jiang Yanli Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut Jiang Zhaohua Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut Wang Fuping Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut Journal of Materials Science Springer US; http://www.springer-ny.com 42/22(2007-11-01), 9434-9439 0022-2461 42:22<9434 2007 42 10853 https://doi.org/10.1007/s10853-007-1842-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-007-1842-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yao Zhongping School of Materials Science and Engineering, Harbin Institute of Technology, 150001, Harbin, PR China aut NATIONALLICENCE 700 1- Jiang Yanli Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut NATIONALLICENCE 700 1- Jiang Zhaohua Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut NATIONALLICENCE 700 1- Wang Fuping Department of Applied Chemistry, Harbin Institute of Technology, 150001, Harbin, PR China aut NATIONALLICENCE 773 0- Journal of Materials Science Springer US; http://www.springer-ny.com 42/22(2007-11-01), 9434-9439 0022-2461 42:22<9434 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer