Porous titanium is used in many bioimplant and electrode applications because of its interconnected pore structure and good corrosion resistance. The purpose of this paper is to study the anodic polarization behavior of porous titanium in different electrolytes and clarify the influences of the porosity and macro‐pore size on the corrosion resistance.
The porous titanium with 10‐70% porosities and average macro‐pore sizes in the range of 100‐500 μm was prepared by the powder metallurgy method using polymethyl methacrylate (PMMA) as a space holder. Electrochemical corrosion tests were performed on porous titanium as well as solid titanium (with the same irregular and isolated micro‐pore structures as that on the interconnected spheroidal macro‐pore walls of porous titanium) in the 0.1 M H2SO4, 1 M NaOH and 0.9% NaCl (37 °C) solutions.
It was found that porous titanium exhibited an active‐passive transition behavior in the 1 M NaOH and 0.1 M H2SO4 solutions. In contrast, a self‐passivation transition behavior was observed in the 0.9% NaCl solution (37 °C).
The paper demonstrates that both the porosity and macro‐pore size of porous titanium play an important role in determining the corrosion rate, rather than the corrosion potential.
