Surface properties of plasma electrolytic oxidation coatings on Ti-alloy in phosphate–based electrolytes with the addition of sodium metasilicate.

We have investigated effects of the sodium metasilicate addition into phosphate-based electrolytes on the surface properties of plasma electrolytic oxidation (PEO)-coated layers on Ti-6Al-4V. The surface properties of the PEO-coated layers have been characterized by using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and contact angle measurements. The study shows that the addition of sodium metasilicate in the phosphate-based electrolytes leads to the roughening surface and the change in the surface composition the PEO-coated layers. In addition, the contact angle of distilled water on the surface of the PEO-coated layers with the sodium metasilicate additive in electrolytes is reduced, resulting in higher surface energy. [ABSTRACT FROM AUTHOR]