Morphology and Porosity of the Surface of Titanium Alloys After Plasma-Electrolytic Oxidation in An Alkaline Environment with Diatomite

Surface morphology and porosity are important functional properties of biocompatible oxide ceramic coatings synthesized on titanium alloys. The effect of the composition of the electrolyte for the plasmaelectrolytic oxidation of Ti-6Al-4V titanium alloy on the roughness and porosity of the formed coatings is clarified. Calcium hydroxylapatite and diatomite were added to the basic alkaline aqueous solution based on potassium and calcium hydroxides, sodium silicate, pyrophosphate, and hexamethophosphate. The addition of calcium hydroxylapatite contributes to the formation of coatings with higher porosity. A 4-time increase in the concentration of electrolyte components and the addition of diatomite (20 g/L), stabilizes the coating synthesis, and coatings with higher roughness (in 3-4 times) and porosity (in 1.9 times) are formed compared to coatings, synthesized in an electrolyte without diatomite. Doubling the duration of synthesis in an environment with diatomite contributes to a further increase in the coating roughness.