The comparison of surface characteristics, physico-chemical and biological properties of 304 stainless steel coated by melt-derived and sol–gel-derived 45S5 bioglass for orthopedic applications

Abstract

The ability of 45S5 bioglass to form a bond to living bone tissue and stimulate bone-cell proliferation may be different for melt- and sol–gel-derived samples. In this research, the differences in corrosion resistance, bioactivity and physical properties between the melt- and sol–gel-derived 45S5 bioglass coated on the surface of austenitic 304 stainless steel (SS) as a dental and orthopedic metallic implant were studied. The morphologies of different coated samples were investigated by scanning electron microscopy (SEM). Then, electrochemical measurements were performed and compared with un-coated ones. In order to investigate the bioactivity and surface reactivity of the coated samples, they were studied in vitro in simulated body fluid (SBF), and their microstructures and electrochemical properties were examined in detail. Immediately after immersion in SBF, reactions occurred on the surface of coated samples, and the obtained results from X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses showed all typical characteristic peaks of hydroxyapatite (HAp). In addition, the coated samples showed an enhanced corrosion resistance and also bioactivity in comparison with un-coated ones, and it is worth mentioning that the sol–gel-derived coated sample showed a higher corrosion resistance and faster forming of the HAp layer, which can be useful for dental and orthopedic metallic implants.