Document Type : Research Paper
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran
The present work aimed to develop the anodic electrophoretic deposition (EPD) of sodium alginate/nano-Bioglass® (Na-Alg/nBG) bioactive nanocomposite coatings on Mg-Zn-Ca alloy without any previous surface pre-treatment (other than polishing). In comparison with other alloys, such as stainless steel or titanium, the density and elastic modulus of magnesium are similar to those of natural bone, and corrosion products of Mg-Zn-Ca alloy are not harmful to the patient body. Alginate is an anionic natural polysaccharide which, due to its low toxicity and biocompatibility, has been studied for different biomedical applications. Through the presence of Bioglass® particles in the coatings, mechanical properties are advanced by increasing adhesion to the substrate and also increases the formation of hydroxyapatite after immersion in simulated body fluid (SBF). A stable water/ethanol EPD suspension was used to produce composite nBG/Alg coating for potential biomedical applications. nBG contents (3 g/L) were studied for a constant concentration of sodium alginate (10 g/L); DC voltage and deposition times varied between 3-20 V and 10-60 seconds, respectively. It has been revealed how electrophoretic deposition (EPD) occurs on the magnesium alloy surface. The coatings composition was analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) and the surface of the coatings was studied with field emission scanning electron microscopy (FESEM). For investigating corrosion protection of bioactive coatings, polarization and electrochemical impedance spectroscopy (EIS) tests were used; samples were immersed in simulated body fluid (SBF) at 37°C and results were compared with the bare uncoated Mg-Zn-Ca alloy. The present work confirmed that electrophoretic deposition is a practical method for the co-deposition of Bioglass® nanoparticles and Na-Alg that can be used to produce a wide range of magnesium alloy coatings with tailored microstructures and surfaces with biomedical applications.