Surface-treated commercially pure titanium for biomedical applications: electrochemical, strustural, mechanical and chemical characterizations

This study aimed to investigate the electrochemical behavior and structural, mechanical and chemical modifications of commercially pure titanium (cp-Ti) with surface subjected to different treatments. Cp-Ti discs with 15 mmm in diameter and 2 mm in thickness were used and divided into 6 groups (n=5) according to surface treatment: machined (control ¿ M), modified by HCl + H2O2 (Cl group), modified by H2SO4 + H2O2 (S group), sandblasted with Al2O3 (Sb group) and post-treatment with HCl + H2O2 (SbCl group) or H2SO4 + H2O2 (SbS group). For the electrochemical assay, standard tests such as open circuit potential, electrochemical impedance spectroscopy (EIS), and potentiodynamic tests were conducted in artificial saliva (pHs 3.0; 6.5 and 9.0) to simulate the oral environment and simulated body fluid solution to mimic the blood plasma. All surfaces were characterized before and after the corrosion spectroscopy (EDS), X-ray diffraction (XRD), surface roughness, Vickers microhardness and surface free energy. Data were evaluated by 2-way ANOVA and Tukey HSD test was used as a post-hoc technique (?=0.05). The sandblasting procedure reduced the corrosion resistance of cp-Ti, while the acid treatment improved its electrochemical stability, mainly samples treated with HCl + H2O2 (p<0.05). At low pH, all treated surfaces behaved negatively (p<0.05). The sandblasted groups presented the highest roughness and Vickers microhardness values (p<0.05). The acid treatment did not alter the roughness values when compared to control (p>0.05). The SbS and Cl group presented the highest and lowest surface energy values, respectively (p<0.05). After the corrosion process, there was an increase in roughness values in Cl and Sb groups when exposed to acid artificial saliva (p<0.05). In sandblasted groups, there was a decrease in microhardness values. The surface free energy increased after corrosion process (p<0.05), except for SbS group. Homogeneity of all discs surface were noted via AFM and MEV. Presence of amorphous titanium was noted for all groups, as well as corundum phase for sandblasted groups. Thus, it is concluded that treatment with HCl + H2O2 improved the electrochemical stability of cp-Ti. Although the sandblasting treatment has improved structural and mechanical properties of cp-Ti, a reduction in its corrosion resistance was noted. Acid saliva negatively affected the corrosion behavior of cp-Ti (AU)