Corrosion and Metal Release Investigation of a Porous Biomedical Vitallium Alloy Coated with 58S Sol-Gel Bioactive Glass

Corrosion and metal release characteristics of cobalt-based alloys are important factors influential on their biomedical applications. This study fabricated a porous Vitallium (CoCrMo) alloy and then coated with a 58S bioglass coating by applying the sol-gel dipping method with 3, 4 and 5 cycles to examine the corrosion and ion release performance of this alloy. For this purpose, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and immersion tests were conducted in the simulated body fluid (SBF) at 37 °C. Also, the released ion measurements were performed by inductive coupled plasma optical emission spectrometry (ICP-OES). SEM examinations on the porous substrate indicated that this porous scaffold exhibited the porosity of 37% and the content of small porosities was decreased; however, the macrospores on the surface were intact after applying bioglass coatings. Furthermore, increasing the dipping cycles led to enhancing the corrosion potential from  − 191 mV (in the uncoated porous sample) to − 98 mV (in the coated porous sample dipped 5 cycles in the bioglass sols). EIS results in SBF demonstrated that the corrosion performance of the coatings was improved by increasing the dipping cycles from 0 to 5. ICP-OES results also proved that the presence of the 58 S bioglass coating on the porous Vitallium decreased the release of cobalt and chromium ions, while it enriched Ca and P, thereby improving the bioactivity of the samples.