SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage

In this work, the SEM and EDS results of porous and enriched in calcium or zinc coatings, which were obtained during 3-minute treatments using Plasma Electrolytic Oxidation (Micro Arc Oxidation) processes on CP Titanium Grade 2 at ramp potentials (linear polarization) from 0 up to 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O and/or 500 g Zn(NO3)2∙6H2O in 1 L H3PO4, are presented. It was found that obtained coatings have pores with different shapes and diameters. The Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, what may suggest hydroxyapatite-like structure (M,Ti)x(PO4)y, where M = {Ca, Zn}.