Biocorrosion and Surface Wettability of Ni-free Zr-Based Bulk Metallic Glasses

Owing to the amorphous structure, bulk metallic glasses (BMGs) demonstrate attractive properties for potential biomedical applications. In this study, three Ni-free Zr-based BMGs including Zr60Cu22.5Fe7.5Al10, Zr60Cu20Fe10Al10 and Zr60Ti6Cu19Fe5Al10 were fabricated by suction casting technique. The biocorrosion behaviors of the BMGs in phosphate buffer solution (PBS, pH=7.4) at 37°C were investigated and compared to crystalline biomaterials including Ti-6Al-4V and 316L stainless steel as controls. The corroded surface morphologies and compositions of the BMGs were evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), respectively. Surface wettability of the samples was determined by static contact angle measurement at room temperature using deionized water. It was found that Zr60Cu20Fe10Al10 BMG showed a higher passive region compared to that of Zr60Cu22.5Fe7.5Al10, however these BMGs exhibited lower pitting corrosion resistance compared to crystalline biomaterials. However, titanium element addition to the Zr-Cu-Al-Fe BMGs exhibited a significant increase in the passive region of the polarization curve and a considerable pitting corrosion resistance improvement. Contact angle measurements showed that all BMGs were smaller than the Berg limit (θ= 65°), i.e. they were hydrophilic, which may enhance cell adhesion of the BMGs in biomedical applications.