Effect of Phosphorous Ion Implantation on the Surface, Crystal Structure, Mechanical, and Electrochemical Properties of Bioresorbable Magnesium for Biomedical Applications

Abstract

Surface attributes of pure Mg such as biocompatibility, mechanical strength and corrosion are clinically important for artificial implants, but its fast degradation post-implantation has drawbacks. Tuning Mg for clinical needs is achieved by techniques like near surface ion implantation. This work is about improving the surface and corrosion rate of bioresorbable magnesium by phosphorous (P) ion implantation with fluences of 1016-1018 ions/cm2 and ion beam accelerating energy of ~ 700 keV by a Pelletron Linear Accelerator. The in vitro degradation rate was examined using electrochemical potential tests in simulated body fluid (SBF). X-ray diffraction and energy-dispersive x-ray spectroscopy confirmed the implantation of P ions by forming an amorphous P-layer on the Mg surface. Surface hardness and electrochemical resistance improved as confirmed by the mechanical and electrochemical tests in SBF, respectively, post-implantation. Medical implants designed by this modified Mg are compliant with the patient’s healing span post-implantation with decreased corrosion rate agreeing with the healing process, avoiding an implant removal surgery post-patient’s recovery.