Available online at www.worldscientificnews.com WSN 77(2) (2017) 242-255 EISSN 2392-2192 SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage Krzysztof Rokosz a , Tadeusz Hryniewicz b, *, Kornel Pietrzak c Division of Bioengineering and Surface Electrochemistry, Department of Engineering and Informatics Systems, Faculty of Mechanical Engineering, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland a-c E-mail address: rokosz@tu.koszalin.pl , Tadeusz.Hryniewicz@tu.koszalin.pl , kornel.pietrzak@s.tu.koszalin.pl *Corresponding author: Tadeusz.Hryniewicz@tu.koszalin.pl ABSTRACT 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 V DC in electrolytes containing 500 g Ca(NO 3 ) 2 ∙4H 2 O and/or 500 g Zn(NO 3 ) 2 ∙6H 2 O in 1 L H 3 PO 4 , 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 (PO 4 ) y , where M= {Ca, Zn}. Keywords: Plasma Electrolytic Oxidation (PEO), Micro Arc Oxidation (MAO), CP Titanium Grade 2, calcium nitrate Ca(NO 3 ) 2 ∙4H 2 O, zinc nitrate Zn(NO 3 ) 2 ∙6H 2 O, ramp voltage, linear polarization