Investigation on corrosion protection of biocompatible silane coating on magnesium biodegradable orthopedic implant in simulated body fluid

Introduction Magnesium (Mg) and its alloys have numerous applications as biodegradable implants and scaffolds, but their fast corrosion and degradation rates could be a problem. Methods In this work, a silane-based coating was developed to slow down the degradation and corrosion rates of AZ31 magnesium alloy as biodegradable orthopedic implant. Coating protection with and without surface pre-treatment of AZ31 magnesium was investigated in phosphate buffer saline (PBS) solution as simulated body fluid at 37℃. NaOH was used to activate alloy surface by forming Mg(OH)2 as surface pre-treatment. The silane coating was then applied on alloy surface by dip coater. Scanning Electron Microscope (SEM) was used to observe the surface morphology, thickness and cracks of the coating. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the corrosion rate of silane coated AZ31 in the PBS at 37ºC. Results Scanning Electron Microscope (SEM) images showed a uniform crack-free 5μm thick coating. Electrochemical Impedance Spectroscopy (EIS) results showed that the corrosion resistance for the sample with surface pre-treatment was greatly improved in the PBS solution

Keywords:

Biodegradable implant , Biocompatible coating , Silane , Corrosion