Influence of Surface Treatment on Corrosion and other Electrochemical Properties of Titanium
Titanium is widely used across many medicinal fields like implantology or surgery. Electrochemical coloring of titanium tools or implants is one of the common ways how to differentiate different sizes or types of each application. Titanium grade 4 plates 50 x 20 x 0.1mm were tested to obtain their electrochemical and other technological properties. Coloring process was done using potential of 15, 30, 45, 60 and 75 Volts for 5s in 1 wt. % citric acid in demineralized water solution. Contact angle of colored surface was measured by sessile drop method. Electrochemical impedance spectroscopy was used for determination of some surface layers parameters like capacitance or resistance. Potentiodynamic polarization was used for corrosion testing of this samples and corrosion potential, polarization resistance or corrosion rate of each sample was found using Taffel or Stern method. There was found that anodization process before coloring decreases significantly corrosion potential. There was also found that higher potential used for coloring results in higher polarization resistance but also decreases corrosion potential. Titanium coloring at 75V results into lowest corrosion rate under 1nm/year and the most noble corrosion potential.
Keywords - Titanium, Coloring, Corrosion properties, Polarization, Biocompatibility