Electrochemical behavior of chemical vapor deposited protective aluminum oxide coatings on Ti6242 titanium alloy

Abstract

The electrochemical behavior at room temperature in a neutral sodium chloride aqueous solution of four types of metallorganic chemical vapor deposited aluminum oxide coatings on commercial Ti6242 titanium alloy was investigated. Polarization and electrochemical impedance curves revealed that porosity free, amorphous alumina coatings provide a two order of magnitude improvement of the corrosion resistance with regard to the bare alloy. Crystallized alumina as well as amorphous AlO(OH) only slightly improve the corrosion resistance of Ti6242. It was demonstrated that metallorganic chemical vapor deposition processed amorphous alumina is a highly promising solution to the protection of titanium alloys against corrosion in salt environments. © 2008 The Electrochemical Society. All rights reserved.