Obtaining and characterization of PEO layers prepared on CP-Ti in sodium dihydrogen phosphate dihydrate acidic electrolyte solution

Abstract Phosphorus-incorporated oxide layers were grown on commercially pure titanium during plasma electrolytic oxidation in sodium dihydrogen phosphate dihydrate solution. Microstructure, mechanical and electrochemical behavior of the surface oxides indicated a dominant anatase and rutile structure of TiO 2 with nanocrystallites ranging from 45 to 64 nm and 48–98 nm, respectively as well as Ti 2+ , Ti 3+ and Ti 4+ chemical species. Using a combination of process time, applied current and electrolyte concentration, coating thicknesses up to about 10 μm were fabricated. Best mechanical performance was observed for potentiostatic deposited samples yielding a 453 HV 300 hardness, 19 N adhesive failure and 38 N full delamination resistance. All PEO-coated samples in this work exhibit a corrosion current density with one order of magnitude lower than CP-Ti when subjected to Ringer's physiological solution.