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

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 TiO2 with nanocrystallites ranging from 45 to 64 nm and 48–98 nm, respectively as well as Ti2+, Ti3+ and Ti4+ 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 HV300 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. •Preparation of PEO oxide layers on CP-Ti in an acid electrolyte solution containing NaH2PO4∙2H2O•Comparison of potentiostatic and galvanostatic regimes on mechanical properties and corrosion resistance of PEO coatings obtained in similar growth conditions•The effect of PEO process time and current intensity during potentiostatic and galvanostatic operation mode on composition, microstructure, mechanical properties and corrosion behavior of oxide coatings•Influence of electrolyte concentration in restricting the growth of anatase - the role of phosphorous incorporation