Plasma electrolytic oxidation is a surface treatment to produce ceramic oxide coatings on light metals like aluminum, magnesium, titanium, and their alloys. Wherever conditions are tough, plasma electrolytic oxidation provides coatings with exceptional durability and performance, based on high hardness, resistance against chemical and corrosive attack, and also allows for tailoring the surface to achieve, for example, thermal isolation or specific radiation emission, absorbance, and reflection properties.