Electroless Deposition of TiO[sub 2]∕Ti onto Aluminum Substrates

Abstract

The stability of titanium-based biomaterials has been linked to Ti O2 film covering the Ti metal. However, the conventional techniques for depositing Ti O2 render its surface modification very difficult. A unique alternative approach appears to be the use of electroless plating. This work discusses an approach for designing Ti O2 Ti membrane using electroless deposition. Deposition was achieved via the chemical reduction of titanium(IV) isopropoxide on aluminum substrates in aqueous-alcoholic media (80% propanol:20% water) using anthracene as reducing agent. The aluminum substrates were initially sensitized and activated with Sn Cl2 and Pt Cl4 in that order, to induce the selective reduction of titanium metal ions. Ethylenediaminetetraacetic acid was used as complexing agent while 2-mercaptobenzothiazole served as stabilizer. Subsequent characterization using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and energy dispersive spectroscopy and electrochemical techniques confirmed that titanium oxides/titanium metals have been electrolessly deposited. Note that aluminum substrates that were not sensitized did not show any evidence of the presence of titanium, indicating that the sensitization and activation steps were necessary to initiate the electroless deposition of titanium. XPS confirmed that the electrolessly deposited surfaces contained Ti atoms in two different chemical environments, specifically Ti Ox Ti atoms. © 2007 The Electrochemical Society.