Electrochemical corrosion behavior of silver doped tricalcium phosphate coatings on magnesium for biomedical application

• PLD technique was employed to fabricate Ag doped TCP coating on Mg substrates and their corrosion properties were tested.
• The size and number of droplet on the surface of the samples were significantly affected by the doping concentration.
• The corrosion protection properties of Ag doped TCP coatings on Mg were dependent on the doping concentration.

This paper investigates the growth, characterization and electrochemical corrosion properties of tricalcium phosphate (TCP) doped with 0 wt%, 1 wt%, 5 wt% and 10 wt% of silver coatings deposited on magnesium substrate using pulsed laser deposition (PLD). The phase and morphological properties of the coatings were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The SEM images showed that increasing the percentage of Ag dopant reduces the size of droplets formed during the deposition process. The corrosion protection behavior of the coated samples was evaluated using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). The corrosion test was performed in Hanks' Balanced Salt Solution and 0.9 wt% saline solution using three electrode electrochemical cell. The results showed that TCP coated magnesium exhibits 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% Ag doping in TCP reduces the corrosion protection behavior. In conclusion, we have developed TCP and TCP doped with 1%, 5% and 10% Ag coating with tunable corrosion protection efficiency.