Abstract:The effects of boride coating on the bioactivity, antibacterial activity, and electrochemical behavior of commercially pure titanium (CP-Ti) in phosphate buffer solution (PBS) with bovine serum albumin (BSA) were studied. The grazing incidence X-ray diffraction (GIXRD) pattern confirmed the formation of a TiB/TiB₂ coating via boriding process. Scanning electron microscopy (SEM) observation indicated that the TiB₂ cross-linked particles covered the TiB whiskers. Water contact angle measurements revealed that boriding led to the formation of a surface with intermediate water affinity. Potentiodynamic polarization (PDP) assays demonstrated that the TiB/TiB₂ coating had acceptable passivation behavior in BSA-containing PBS. Electrochemical impedance spectroscopy (EIS) measurements revealed that the passivation behavior of the CP-Ti and the borided samples was improved by increasing exposure time. Based on the Mott-Schottky (M-S) tests, it was realized that the charge carriers of passive films of both samples decreased with increasing exposure time in BSA-containing PBS. The bioactivity test results in a simulated body fluid showed that the TiB/TiB₂ coating switched the CP-Ti from bioinert to bioactive material. Finally, the antibacterial activity test of the TiB/TiB₂ coating against Escherichia coli and Staphylococcus aureus indicated 99% antibacterial activity.

Key words: electrochemical behavior; boriding; BSA-containing PBS; passive film; titanium boride