Anodic Dissolution of Titanium in Ethylene Glycol Solution Containing Chloride Salt

摘要

The role of chloride ions during anodic dissolution of titanium in chloride salt-containing ethylene glycol solutions was investigated with a rotating disk electrode and electrochemical impedance spectroscopy. The chloride ions were necessary to improve solution conductivity in dilute solutions, while they decreased the dissolution current in concentrated solutions. The dissolution rate under the mass transfer condition was determined by diffusion of titanium species dissolved from the electrode, and the formation of a highly concentrated titanium chloride salt on the electrode was suggested. The most likely chloride salt as a dissolution product on the titanium substrate was TiC1_4, which might be present at the bottom of the diffusion layer and exhibit characteristic impedance behaviors. The rate of diffusion of titanium chloride in the solution regulates the whole dissolution rate of titanium in the solution.