Advances in Plasma Electrolytic Oxidation (PEO) for Surface Engineering

Dear Colleagues,

Plasma electrolytic oxidation (PEO), also known as micro-arc oxidation, has emerged as a powerful surface engineering technique for the development of robust, multifunctional coatings on lightweight metals such as aluminum, magnesium, and titanium and their alloys. Building on the principles of conventional anodization, PEO utilizes high-voltage plasma discharges in electrolytic environments to create dense, adherent, and wear- and corrosion-resistant oxide layers. Over the past two decades, the method has attracted substantial scientific and industrial attention owing to its versatility in tailoring coating microstructure, composition, and functionality by careful control of process parameters, electrolyte chemistry, and electrical regimes.

The growing demand for advanced surface modification techniques in aerospace, automotive, biomedical, and energy-related industries underscores the importance of PEO. As lightweight alloys continue to replace traditional structural materials to improve energy efficiency and sustainability, their inherent susceptibility to corrosion and mechanical degradation poses significant challenges. PEO offers a sustainable, environmentally friendly approach to overcome these limitations by enabling the fabrication of protective and multifunctional coatings that extend component life, enhance performance, and enable new functionalities such as self-lubrication, photocatalysis, or bioactivity.

More recently, low-voltage PEO (LV-PEO) has emerged as a particularly promising development. By reducing the energy input required to initiate and sustain plasma discharges, LV-PEO broadens the practical applicability of this technology, offering energy savings, improved process control, and compatibility with more delicate substrates. This approach not only enhances sustainability but also provides new pathways to engineer thin, uniform, and functionally graded coatings that can address the specific requirements of biomedical devices, microelectronics, and other advanced technologies where conventional high-voltage regimes may be unsuitable. The exploration of LV-PEO represents a significant frontier for both scientific discovery and industrial implementation.

This Special Issue aims to bring together recent advances in the science, technology, and applications of plasma electrolytic oxidation for surface engineering. Contributions are invited that address both the fundamental understanding of plasma–electrolyte–substrate interactions and the practical development of novel coating architectures with targeted properties. Specific topics of interest include, but are not limited to, the following:

• Mechanisms of coating formation, plasma discharge behavior, and in situ characterization methods.
• Tailoring microstructure, phase composition, and properties through process design and electrolyte formulation.
• Advances in low-voltage PEO processes for improved efficiency and novel applications.
• Advanced characterization of coating performance under extreme environments (corrosion, wear, thermal, or fatigue).
• Multifunctional and nanostructured PEO coatings for biomedical, energy, and environmental applications.
• Integration of PEO with other surface engineering or additive manufacturing techniques.
• Scale-up, industrial implementation, and sustainability of PEO technologies.

By highlighting cutting-edge research in this rapidly evolving field, this Special Issue will serve as a platform for academic and industrial researchers to exchange knowledge and foster collaboration. It will provide a comprehensive view of the current challenges and future opportunities in plasma electrolytic oxidation—including low-voltage approaches—reinforcing its importance as a cornerstone of modern surface engineering.

We look forward to receiving your contributions!

Prof. Dr. Chang-Hwan Choi
Guest Editor

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• plasma electrolytic oxidation (PEO)
• low-voltage PEO (LV-PEO)
• surface engineering
• multifunctional coatings
• lightweight alloys