The fabrication of a ceramic coating on the metallic substrate is usually applied to achieve the improved performance of the material. Plasma electrolytic oxidation (PEO) is one of the most promising methods to reach this performance, mostly wear and corrosion resistance. Traditional PEO is carried out in an aqueous electrolyte. However, the current work showed the fabrication and characterization of a ceramic coating using PEO in molten salt which was used to avoid disadvantages in system heating-up and the formation of undesired elements in the coating. Aluminum 7075 alloy was subjected to the surface treatment using PEO in molten nitrate salt. Various current frequencies were applied in the process. Coating investigations revealed its surface porous structure and the presence of two oxide layers, α-Al₂O₃ and γ-Al₂O₃. Microhardness measurements and chemical and phase examinations confirmed these results. Potentiodynamic polarization tests and electrochemical impedance spectroscopy revealed the greater corrosion resistance for the coated alloy. Moreover, the corrosion resistance was increased with the current frequency of the PEO process.

中文翻译：

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熔盐中的等离子体电解氧化法制备Al7075合金陶瓷涂层。

通常采用在金属基材上制造陶瓷涂层的方法，以提高材料的性能。等离子体电解氧化（PEO）是达到这一性能的最有前途的方法之一，主要是耐磨性和耐腐蚀性。传统的PEO是在水性电解质中进行的。但是，当前的工作表明了在熔融盐中使用PEO来制造和表征陶瓷涂层的方法，该涂层用于避免系统升温和涂层中不希望有的元素形成的缺点。7075铝合金在熔融硝酸盐中使用PEO进行了表面处理。在该过程中施加了各种电流频率。涂覆调查显示它的表面的多孔结构和两个氧化物层的存在，的α-Al ₂ ö₃和γ-Al系₂ ö ₃。显微硬度测量以及化学和相检查证实了这些结果。电位动力学极化测试和电化学阻抗谱显示涂层合金具有更高的耐腐蚀性。而且，随着PEO工艺的当前频率，耐腐蚀性增加。