Effects of electric parameters on microstructure and properties of MAO coating fabricated on ZK60 Mg alloy in dual electrolyte
来源期刊：Rare Metals2012年第2期
论文作者：CHEN Jing a, b , WANG Zexin a , and LU Sheng a a School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang , China b School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang , China
文章页码：172 - 177
摘 要：Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 on ZK60 Mg alloys to explore the effect of electric parameters including current density, frequency, duty cycle and oxidation time on the evolution of coatings and other characteristics. The microstructural characteristics of coatings were observed by scanning electron microscopy （SEM） combined with the analysis of voltage-time responses during MAO process. Test of weight loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The results indicate that the current density and duty cycle play key roles on the coating quality. The peak voltage during MAO process increased with the increase in current density but the coating would be more easily detached when the current density was beyond a critical value. Voltage during MAO and microstructure of the coating were affected remarkably by duty cycle, and corrosion resistance was improved greatly when duty cycle was 40%. By means of single variable experiments, MAO process with optimized electric parameters was developed, which corresponds to the current density of 20 A dm 2 , frequency of 500 Hz, duty cycle of 40% and oxidation time of 15 min.
CHEN Jing a, b , WANG Zexin a , and LU Sheng a a School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China b School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
摘 要：Micro-arc oxidation （MAO） process was carried out in a dual electrolyte system of NaAlO 2 and Na 3 PO 4 on ZK60 Mg alloys to explore the effect of electric parameters including current density, frequency, duty cycle and oxidation time on the evolution of coatings and other characteristics. The microstructural characteristics of coatings were observed by scanning electron microscopy （SEM） combined with the analysis of voltage-time responses during MAO process. Test of weight loss was conducted at a 3.5% NaCl solution to assess the resistance to corrosion. The results indicate that the current density and duty cycle play key roles on the coating quality. The peak voltage during MAO process increased with the increase in current density but the coating would be more easily detached when the current density was beyond a critical value. Voltage during MAO and microstructure of the coating were affected remarkably by duty cycle, and corrosion resistance was improved greatly when duty cycle was 40%. By means of single variable experiments, MAO process with optimized electric parameters was developed, which corresponds to the current density of 20 A dm 2 , frequency of 500 Hz, duty cycle of 40% and oxidation time of 15 min.
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