Plasma Electrolytic Oxidation as a modern method to form porous coatings enriched in phosphorus and copper on biomaterials

In the paper, the porous coatings obtained on niobium and two titanium alloys (Ti6Al4V, and TNZ) after Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation, were studied. The samples were treated at the voltage of 450 V for 3 minutes in the electrolyte consisting of 300 g and 600 g of copper nitrate Cu(NO3)2 in 1 litre of concentrated phosphoric acid H3PO4, consecutively. SEM and EDS studies were performed on the samples. Based on the obtained results it may be concluded that enriched in copper porous coatings on all studied materials were created in the electrolyte within copper nitrate amounting for 600 g. The proposed by the Authors factor to evaluate the obtained coatings, i.e. copper-to-phosphorus ratio, which for the studied materials amounted to 0.21, clearly indicates that the performed electrochemical PEO treatment for surface modification especially of bioimplants may be advised.