Modification of the titanium oxide morphology and composition by a combined chemical-electrochemical treatment on cp Ti

Ernesto Peláez-Abellán,Romeu Cardozo Rocha-Filho,Nerilso Bocchi,Laís Tereza Duarte,Sonia Regina Biaggio

doi:10.1590/s1516-14392012005000002

Ernesto Peláez-Abellán, Romeu Cardozo Rocha-Filho + Show 3 more

Open Access

https://doi.org/10.1590/s1516-14392012005000002

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Journal: Materials Research	Publication Date: Jan 20, 2012
Citations: 18	License type: cc-by

Affiliation: Universidade Federal de São Carlos

Abstract

A combined chemical-electrochemical oxidation method to obtain porous bioactive TiO2 films on titanium is reported. In this case, a titanium chemical pre-etching followed by the micro-arc oxidation (MAO) treatment is proposed and optimized, to obtain a high-roughness and porous surface which benefits the titanium/bone integration. The MAO treatment at various rates (different current densities) allowed to define the influence of the oxide growth rate on the surface morphology and to design the best features for each case. Titanium samples were pre-etched using a 2% HF solution as a function of the etching time, and then anodized by the MAO treatment in a 0.5 M H3PO4 solution at current densities in the 10 to 90 mA.cm-2 range. High porosity (0.5 to 1 µm-diameter pores) and higher phosphorous content for TiO2 films were achieved by first etching the Ti sample for 180 seconds in the HF solution, and then applying current densities in the 80 to 90 mA.cm-2 range for the micro-arc oxidation process.

Highlights

Titanium oxide films have attracted much attention due to their potential applications in catalysts, sensors, solar cells, microelectronic devices, and microwave communication systems
A previous etching step in a 2% HF aqueous solution was proposed in order to remove the native oxide grown in air during the titanium handling process and to provide a reproducible surface for the subsequent micro-arc oxidation process
The oxide outer layer dissolution was higher for increasing etching times, revealing a new Ti surface characterized by grooves and ridges oriented in the direction of the previous grinding; the light-gray parts on the surface at lower etching times indicate the remaining undissolved outer layer

Summary

Introduction

Titanium oxide films have attracted much attention due to their potential applications in catalysts, sensors, solar cells, microelectronic devices, and microwave communication systems. MAO coatings may have specific surface structures such as amorphous phase, non-equilibrium solids and mixed compounds, since complex plasma reactions, such as ionization and plasma condensation, may occur at the electrode surface during the oxide growth[8] All these aspects certainly change the morphological and the corrosion properties of the oxide film protecting the biomaterial. Titanium is par excellence the material used as orthopedic and dental implant in the human body; it is bioinert by nature For this reason, investigations with the purpose of modifying its surface in order to turn it bioactive have been frequently reported in the literature. We report on a combined chemical-electrochemical oxidation method to obtain porous TiO films on titanium In this case, a combination of a chemical pre-etching followed by the MAO treatment is proposed and optimized. The roughness parameters, the pore configuration and the phosphorous incorporation of the as-obtained TiO2 films are analyzed as a function of the oxide growth conditions

Experimental

Morphology and roughness of the titanium surface after the etching treatment

Roughness of the titanium oxide film after the micro-arc anodization

Conclusions