Corrosion Behavior Of Tricalcium Phosphate Doped With Different Compositions Of Silver

In this study, magnesium (Mg) disks were coated with beta-tricalcium phosphate (beta-TCP) doped with different mass percent of silver (Ag) (0 wt%, 1 wt%, 5 wt% and 10 wt%) in an effort to modulate the detrimental osteoimmunomodulatory properties and colonization of bacteria on Mg disk, due to the reported favorable osteoimmunomodulatory properties of beta-TCP and antibacterial properties of Ag. This paper describes the growth, characterization and corrosion analyses of beta-TCP doped with different compositions of Ag thin film coatings. The phase composition and microstructure analyses were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The SEM images showed that varying the percentage of Ag dopant affects the surface morphology of the beta-TCP coatings. The corrosion protection behavior of the coated samples were evaluated using electrochemical measurement techniques, such as potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). The corrosion tests were performed in Hank's Balanced salt solution using a three electrode electrochemical cell. The results showed that the beta-TCP coating and beta-TCP doped with Ag coatings on the Mg disks exhibit a much superior stability and lower corrosion rate compared to bare Mg. It was observed that increasing the mass of the Ag dopant increases the corrosion protection, but 10 wt% Ag doping in beta-TCP reduces the corrosion protection behavior. The SEM images of the samples after corrosion show that the beta-TCP and beta-TCP doped with 10 wt% Ag suffered the most corrosion attack compare to beta-TCP doped with 1 wt% and 5 wt% Ag. In conclusion, we have developed beta-TCP and beta-TCP doped with 1 wt%, 5 wt% and 10 wt% Ag coating with tunable corrosion protection efficiency above 88%.