Effects of Surface Integrity on In-Vitro Corrosion of Biodegradable Magnesium-Calcium Orthopedic Implants

Biodegradable magnesium-calcium (MgCa) alloys are capable of gradually dissolving and becoming absorbed in the human body after implantation. The critical issue that hinders the application of MgCa implants is their fast corrosion rate in human body fluids. A promising approach to tackle this issue is to tailor surface integrity of orthopedic implants for tuning the corrosion kinetic. The synergistic dry cutting and burnishing is used in this study to modify surface integrity of MgCa0.8 (wt%) implants for controlled corrosion performance. The effects of cutting speed and rolling force, as key parameters in the synergistic dry cutting-finish burnishing, on the electrochemical responses of the processed surfaces are investigated in the simulated body fluid (SBF). Potentiodynamic polarization curves are measured, and morphology and elemental composition of corroded surfaces are studied utilizing scan electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively.