# Electrochemical Oxidation of Ti-Grad 23 Alloy for Biomedical Applications: Influence of TiO2 Formation on Their Morphology, Composition, Wettability, and Chemical Corrosion

## TL;DR

This paper studies how electrochemical oxidation affects the properties of a titanium alloy used in biomedical applications, focusing on the formation of TiO2 layers and their performance in simulated body conditions.

## Contribution

The study identifies optimal electrochemical oxidation conditions for Ti-Grad 23 alloy to enhance its biomedical suitability through controlled TiO2 layer formation.

## Key findings

- Electrochemical oxidation increases the crystallite size and intensifies anatase and brookite TiO2 phases.
- Oxidized surfaces show enhanced hydrophilicity and structural stability in physiological media.
- Optimal oxidation occurs at 200 V for 1 min, producing uniform pores suitable for biomedical use.

## Abstract

In this study, the influence of the electrochemical oxidation process on Ti-Grad 23 alloy (Ti6Al4V ELI) in 1 M H3PO4, under applied voltages between 200 and 275 V, at a constant time of 1 min, is analyzed. The structural, morphological, and wettability properties of the TiO2 anodic layers obtained were investigated by X-ray diffraction (XRD), energy dispersive electron microscopy (SEM-EDS), contact angle measurements, and chemical corrosion. XRD analysis showed the development and intensification of anatase and brookite phases, with increased crystallite size after electrochemical oxidation. SEM/EDS characterization confirmed the formation of an inhomogeneous porous TiO2 layer, with pore diameters ranging from 98 to 139 nm and a significant increase in oxygen content. Contact angle measurements demonstrate enhanced hydrophilicity for all oxidized samples, with progressively lower values as the applied voltage increased. Chemical corrosion tests in Ringer solution and Ringer + 40 g/L H2O2 indicated that oxidized surfaces maintain structural stability in physiological media, whereas exposure to oxidizing environments induces partial pore closure and crack formation due to localized corrosion. The optimal anodizing condition was identified at 200 V for 1 min, yielding a uniform distribution of pores and improved morpho-functional characteristics suitable for biomedical applications. The optimal electrochemical oxidation conditions were identified at 200 V for 1 min, ensuring a uniform pore distribution.