Formation of a Spinel Coating on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation
Formation of a Spinel Coating on AZ31 Magnesium Alloy by Plasma Electrolytic Oxidation
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DOI：
10.1007/s11665-016-1917-7
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发表时间：
2016-01
影响因子：
2.3
通讯作者：
Max Sieber;F. Simchen;I. Scharf;T. Lampke
中科院分区：
文献类型：
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作者：
Max Sieber;F. Simchen;I. Scharf;T. Lampke
等离子体电解氧化（PEO）是轻金属表面改性的常用方法。然而，在稀电解质中镁基材的PEO通常导致形成由不利的MgO氧化镁组成的涂层。通过引入电解质组分，可以改变氧化物涂层的相组成。在含有氢氧化物、铝酸盐和磷酸盐阴离子的电解液中，通过PEO生产完全由MgAl2O4镁铝尖晶石组成的涂层。涂层的平均硬度为3.5GPa（马顿氏硬度）。与裸基体相比，涂层在稀氯化钠溶液中的腐蚀电流密度降低了约10%。一个数量级，并使腐蚀电位向更高的值略微偏移。
Plasma electrolytic oxidation (PEO) is a common means for the surface modification of light metals. However, PEO of magnesium substrates in dilute electrolytes generally leads to the formation of coatings consisting of unfavorable MgO magnesium oxide. By incorporation of electrolyte components, the phase constitution of the oxide coatings can be modified. Coatings consisting exclusively of MgAl2O4magnesium-aluminum spinel are produced by PEO in an electrolyte containing hydroxide, aluminate, and phosphate anions. The hardness of the coatings is 3.5 GPa on Martens scale on average. Compared to the bare substrate, the coatings reduce the corrosion current density in dilute sodium chloride solution by approx. one order of magnitude and slightly shift the corrosion potential toward more noble values.