Corrosion resistance enhancement of Ti–47Al–2Cr by thermal treatment in a controlled atmosphere

Abstract

Purpose

The purpose of this paper is to investigate the effect of thermal treatment at low partial pressure of oxygen on electrochemical corrosion resistance of Ti‐47Al‐2Cr (at %) intermetallic, known as γ‐TiAl alloy.

Design/methodology/approach

The surfaces of the samples were modified by thermal treatment at different temperatures in N₂ gas flow for an hour. Characterization of the modified surface layers was carried out by microscopic examinations, hardness and roughness tests, and X‐ray diffraction analyses. Potentiodynamic polarization was used to evaluate the corrosion performance of γ‐TiAl in Ringer's solution.

Findings

The results indicated that the alloy treated at 950 °C had the optimum corrosion resistance, which can be attributed to the formation of an oxide layer by the surface thermal treatment and increase of the passive layer thickness.

Practical implications

Low corrosion rate (CR), high pitting potential (Epit), and more noble corrosion potential (Ecorr) make it possible for γ‐TiAl to be considered as a candidate for biomedical applications.

Originality/value

The treatment described in the paper is a novel method for surface modification of this type of alloy and results showed that it was an effective treatment and that the corrosion resistance improved remarkably.

Citation

Saebnoori, E., Shahrabi, T., Sabour Rouhaghdam, A. and Jafarian, M. (2012), "Corrosion resistance enhancement of Ti–47Al–2Cr by thermal treatment in a controlled atmosphere", Anti-Corrosion Methods and Materials, Vol. 59 No. 2, pp. 51-56. https://doi.org/10.1108/00035591211210802