Mechanism of Improvement for Titanium Corrosion Resistance by Using Albumin

Objective: We reported that albumin in solution with fluoride prevented titanium corrosion. In this study, the mechanism of the control of corrosion by albumin was investigated by an analysis of electrochemical behavior and the rate of titanium dissolution in solutions with or without albumin. Method: Commercially pure titanium plates were polished with SiC paper. The electrochemical properties were examined in three different solutions: 0.2% NaF + 0.9% NaCl (NAF), 0.1% albumin + 0.9% NaCl (ASS), and 0.1% albumin + 0.2% NaF + 0.9% NaCl (AFS). In addition, the electrochemical properties of some specimen were examined in NAF after immersion in ASS for 4 hours (denoted as CAF). Each condition was repeated with five specimens. The rate of titanium dissolution was examined after immersion in NAF or AFS for up to 168 hours, and the concentration of dissolved titanium was analyzed using inductively coupled plasma emission spectroscopy (n=3). The results were subjected to ANOVA and Scheffe's test (α=0.05). Results: The electrochemical properties indicated that the specimens in ASS had better corrosion resistance than did those in NAF, AFS, and CAF. Among those in other solutions, specimens in NAF had the least corrosion resistance. An interesting finding was that no significant difference was detected in electrochemical properties between AFS and CAF. Regarding the rate of dissolved titanium, the titanium concentration in NAF was greater than that in AFS after immersion for 72 and 168 hours, although the dissolution behavior in NAF was similar to that in AFS within 24 hours. Conclusion: We suggested that the albumin adsorbed on titanium protected against an attack by fluoride rather than suppressing release of titanium compounds.