This work was made to investigate how nucleation and growth behavior of the coating film were affected by surface topographies of Mg–Al–Zn alloy substrate during the initial stage of plasma electrolytic oxidation (PEO). To satisfy this end, a single substrate was prepared by mechanical treatment exhibiting rough and smooth regions with an equal area on the surface. The rough region with prominent hills and grooves induced the breakdown of passive film, which was indicated by an early appearance of plasma discharge on the rough region since nucleation of coating film occurred preferentially around the hills. However, the coating film grown on the grooves was somewhat thicker and more porous than the film grown on the hills and smooth regions. This was due to the fact that the growth of the coating film was found to be localized in the presence of rough region, which was in line with the discharge activities. Herein, the nucleation and growth behavior during the initial stage of PEO will be discussed schematically on the basis of microstructural interpretation.

这项工作旨在研究在等离子体电解氧化 (PEO) 的初始阶段，Mg-Al-Zn 合金基体的表面形貌如何影响镀膜的成核和生长行为。为了满足这一目的，通过机械处理制备了一个单一的基板，该基板在表面上具有相同面积的粗糙和光滑区域。具有突出丘陵和凹槽的粗糙区域引起钝化膜的破坏，这表现为粗糙区域早期出现等离子体放电，因为涂层膜的成核优先发生在丘陵周围。然而，在凹槽上生长的涂膜比在丘陵和光滑区域上生长的膜厚一些且多孔。这是因为发现涂层膜的生长在粗糙区域的存在下是局部的，这与放电活动一致。在此，将在微观结构解释的基础上示意性地讨论 PEO 初始阶段的成核和生长行为。