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›› 2009, Vol. 9 ›› Issue (3): 592-597.

• 材料工程专栏 • 上一篇    下一篇

Growth and Corrosion Characteristics of Plasma Electrolytic Oxidation Ceramic Films Formed on AZ31 Magnesium Alloy

王丽 陈砺 严宗诚 王红林 彭家志   

  1. 华南理工大学化学与化工学院 华南理工大学化学与化工学院 华南理工大学学与能源学院 华南理工大学化学与能源学院 华南理工大学化学与能源学院
  • 收稿日期:2008-12-23 修回日期:2009-03-23 出版日期:2009-06-20 发布日期:2009-06-20
  • 通讯作者: 王丽

Growth and Corrosion Characteristics of Plasma Electrolytic Oxidation Ceramic Films Formed on AZ31 Magnesium Alloy

WANG Li CHEN Li YAN Zong-cheng WANG Hong-lin PENG Jia-zhi   

  1. College of Chemistry and Chemical Engineering, South China University of Technology, College of Chemical and Energy Engineering, South China University of Technology College of Chemical and Energy Engineering, South China University of Technology College of Chemical and Energy Engineering, South China University of Technology College of Chemical and Energy Engineering, South China University of Technology
  • Received:2008-12-23 Revised:2009-03-23 Online:2009-06-20 Published:2009-06-20
  • Contact: WANG Li

摘要: The growth characteristics of oxide ceramic films formed on AZ31 magnesium alloy with plasma electrolytic oxidation (PEO) technique in alkaline silicate solution were investigated. The composition, structure and morphology of the coatings were detected by energy dispersive X-ray spectroscope and scanning electron microscope. The amount of dissolved magnesium in the electrolytes during PEO process was measured by atomic absorption spectrometry. The results indicated that the growth process of PEO films had three stages when applied with constant voltage mode. In the first stage, the growth rate of PEO films was low, and concentrations of elements O, Mg and Si varied slightly. After sparking occurred (the second stage), the PEO films showed higher growth rate due to the high transfer rate of ions and electrons, and the existence of plasma reactions. When the growth rate tended to maintain stable with time, the third stage happened. PEO films exhibited different uniform and pitting-corrosion characteristics in different reaction stages. The films formed at 300 V for 30 min performed best corrosion resistance and the phase of ceramic films was mainly composed of MgSiO3 and forsterite Mg2SiO4.

关键词: magnesium alloy, plasma electrolytic oxidation, oxidation film, growth process

Abstract: The growth characteristics of oxide ceramic films formed on AZ31 magnesium alloy with plasma electrolytic oxidation (PEO) technique in alkaline silicate solution were investigated. The composition, structure and morphology of the coatings were detected by energy dispersive X-ray spectroscope and scanning electron microscope. The amount of dissolved magnesium in the electrolytes during PEO process was measured by atomic absorption spectrometry. The results indicated that the growth process of PEO films had three stages when applied with constant voltage mode. In the first stage, the growth rate of PEO films was low, and concentrations of elements O, Mg and Si varied slightly. After sparking occurred (the second stage), the PEO films showed higher growth rate due to the high transfer rate of ions and electrons, and the existence of plasma reactions. When the growth rate tended to maintain stable with time, the third stage happened. PEO films exhibited different uniform and pitting-corrosion characteristics in different reaction stages. The films formed at 300 V for 30 min performed best corrosion resistance and the phase of ceramic films was mainly composed of MgSiO3 and forsterite Mg2SiO4.

Key words: magnesium alloy, plasma electrolytic oxidation, oxidation film, growth process

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