Influence of pulse frequency on the morphological and corrosion characteristics of the plasma electrolytic oxidized ZM21 magnesium alloy

• Main Authors: Hariprasad, S., Varma, Arjun, Saikiran, A., Arun, S., Parfenov, E.V., Rameshbabu, N.
• Format: Conference Proceeding
• Language: English
• Subjects: Corrosion protection; Frequency; Magnesium; Plasma electrolytic oxidation; Wettability; ZM21
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2020.05.366

•Effect of pulse frequency on PEO of ZM21 alloy was studied.•ZM21 alloy PEO treated at higher frequency showed superior corrosion resistance.•PDP test results well matched with the EIS test results. The process of plasma electrolytic oxidation was employed to fabricate ceramic oxide layer over the surface of ZM21 Mg alloy. PEO coatings were developed in an electrolyte composed of 10 g L−1 Na2SiO3·9H2O, 4 g L−1 KOH and 2 g L−1 Na2B4O7·10H2O in deionized water. The influence of pulse frequency on coating formation at 50 Hz and 1000 Hz was studied. The surface morphology and the phase analysis of the coatings were assessed by the SEM and XRD techniques, respectively. The corrosion performance of the coated specimens along with the bare substrate was studied by potentiodynamic polarization (PDP) and the electrochemical impedance spectroscopy (EIS) tests in the simulated body fluid (SBF) solution. The coating produced at 1000 Hz frequency showed the most favourable surface morphology and corrosion resistance, thereby enabling the suitable prototype for further development of corrosion resistant coatings for biodegradable magnesium implants in biomedical applications.