The action of anodic TiO₂ coating against thermal oxidation of pure titanium

Author(s)

Kuroda, Pedro A. B. ; Cardoso, Giovana C. ; Rossi, Mariana C. ; Afonso, Conrado R. M. ; Grandini, Carlos R.

• Document type: Journal article
• Source: Journal of Materials Science; v. 60, n. 4, p. 14-pg., 2025-01-03.

Abstract

This study aims to produce a micro-arc oxidation (MAO) layer of TiO2 on commercially pure titanium (CP-Ti) and analyze the influence of heat treatment temperatures in the air to promote thermal oxidation and in a vacuum to prevent oxidation. The results showed that the MAO coating is amorphous and constituted by TiO2 as anatase and rutile. The increase in heat treatment temperature (600-1200 degrees C) promoted the formation of rutile, an increase in surface roughness, but decreased the contact angle and pore size. In the condition subjected to heat treatment in vacuum, there is also a decrease in the thickness of the layer due to atomic diffusion (13 -> similar to 0 mu m). On the other hand, the heat treatment out of vacuum oxidized the CP-Ti MAO surfaces, increasing the oxide thickness as the temperature increased (9 -> 325 mu m). The increased hardness of CP-Ti at the metal/oxide interface was high due to the incorporation of oxygen in solid solution, which acts as a hardening agent. The MAO coating acts as an effective protective layer of the metal substrate against thermal oxidation. (AU)

• FAPESP's process: 18/18293-8 - Titanium alloys: phase transformations and additive manufacturing applied to obtaining functionally graded materials
• Grantee: Rubens Caram Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/26517-6 - Influence of the microstructure and phases on surface functionalization of beta Ti-25Ta-xZr- alloys system
• Grantee: Pedro Akira Bazaglia Kuroda
• Support Opportunities: Scholarships in Brazil - Post-Doctoral