Electrochemical response of ZrCN-Ag-a(C,N) coatings in simulated body fluids

In this study, Zr-C-N-Ag coatings were deposited by magnetron sputtering aiming to provide an enhanced corrosion resistance to stainless steel 316 L, while adding antibacterial capabilities using silver, a wellknown antibacterial agent. The films were analysed by X-ray diffraction, Raman spectroscopy, electron probe microanalysis and X-ray photoelectron spectroscopy (XPS) in relation to the chemical composition and structural characteristics. Additionally, electrochemical impedance spectroscopy and potentiodynamic tests were carried out as a function of the immersion time, in Hanks’ balanced salt solution with 10 g/L of Bovine serum albumin (BSA), to evaluate the electrochemical characteristics of the samples. The results revealed that the coatings are predominantly composed by ZrCxN1 x, Ag and amorphous carbon phases. A large deterioration of the electrochemical stability of the films was evidenced as the silver content increased. The presence of amorphous carbon phases negatively influenced the polarization resistant, behavior ascribed to morphological changes. The immersion test showed a progressive increment of the polarization resistance with time, attributed to surface and pores passivation, due to the formation of both ZrO2 and albumin protective layers on the surface, as shown by XPS.This research is partially sponsored by FEDER funds through the program COMPETE- Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundação para a Ciência e a Tecnologia, under the projects ANTIMICROBCOAT - PTDC/CTM/102853/2008 and in the framework of the Strategic Projects PEST-C/FIS/UI607/2013”, PEST-C/EME/UI0285/2013 and SFRH/BD/80947/2011.