Abstract

ESTUPINAN-DURAN, Hugo Armando  and  LEAL-MARIN,, Sara María. EIS, Mott Schottky and EFM analysis of the electrochemical stability and dielectric properties of Ca-P-Ag and Ca-P-Si-Ag coatings obtained by plasma electrolytic oxidation in Ti6Al4V. Rev.fac.ing.univ. Antioquia [online]. 2017, n.83, pp.9-19. ISSN 0120-6230.  https://doi.org/10.17533/udea.redin.n83a02.

Ti6Al4V ELI (ASTM F136) alloy is one of the most used alloys in devices for osteosynthesis and joint replacement. However, the properties of this alloy can be improved regarding biocompatibility and the osteointegration with the bone tissue through coatings. The aim of this study was the evaluation of the electrochemical behavior of a coating obtained by plasma electrolytic oxidation on Ti6Al4V ELI, using electrolyte solutions enriched with PO4 2-, Ca+2, Si+4 ions and various concentrations of Ag+1. The coatings were characterized by electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) in a three-electrode cell with a simulated physiological solution. The electrochemical behavior was compared with electrostatic force microscopy (EFM). The EIS results showed improved stability properties in corrosion for Ca-P-Ag coatings, compared with Ca-P-Si-Ag. Nyquist and Bode Spectra showed relaxations related to charge transference to the double electrochemical layer and the reflex of the microstructural changes and conductivity of the coating given by its composition. According to with M-S results, all the samples showed an n-type conductivity increased with silver inclusion. The potential, the phase, and amplitude of the coatings with silver inclusion compared to uncoated Ti6Al4V were observed by EFM.

Keywords : Plasma electrolytic oxidation; electrochemical analysis; Ti6Al4V; coating; EFM.

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