Specific features of etching of ultrafine- and coarse-grained titanium in base and acid solutions of hydrogen peroxide

The character and kinetics of chemical etching of nanostructured titanium in base (NH₄OH/H₂O₂) and acid (H₂SO₄/H₂O₂) solutions of hydrogen peroxide (Piranha) were studied. A study of the etching kinetics showed that the etching rate of the nanostructured titanium is not constant and tends to decrease, but in the case of the sulfuric acid solution the decrease is smoother owing to the growth of the oxide layer. The etching rate for ultrafine-grained titanium is higher than for the coarse-grained sample. The applied significance of the study is associated with the fact that Piranha solutions show promising for cleaning, hydrophilizing, and making rough the titanium surface for use in medical implants.