Effects of KMnO₄ on microstructure and corrosion resistance ofmicroarc oxidation coatings on 2024 aluminum alloy

来源期刊：中南大学学报(英文版)2010年第2期

论文作者：杨巍 蒋百灵 时惠英 鲜林云

文章页码：223 - 227

Key words：2024 aluminum alloy; KMnO₄; microarc oxidation; microstructure; corrosion resistance

Abstract: Microarc oxidation (MAO) coatings were prepared on 2024 aluminum alloy in a Na₂SiO₃-KOH electrolyte with KMnO₄ addition varying from 0 to 4 g/L. The microstructure and phases of the coatings were characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD), respectively. The corrosion resistance of MAO coatings was evaluated by electrochemical potentiodynamic polarization in 5% (mass fraction) NaCl solution. The results show that when KMnO₄ is added into base electrolyte, the growth speed of oxide coatings is increased obviously. The main phase of oxide coatings is Al₂O₃, and the contents of MnO₂ and Mn₂AlO₄ phases are increased at the top of oxide coatings with increasing the concentration of KMnO₄. The solute elements participate in forming the oxide coatings. When a proper concentration of KMnO₄ (2.5 g/L) is added into the base solution, the micropores of the MAO coatings are small and compact, and the corrosion resistance of oxide coatings is increased largely.

基金信息：the National Key Technologies Research and Development Program of China