Electrochemical dissolution behaviour of Ti90Al6V4 and Ti60Al40 used for ECM applications

The dissolution behaviour of two different titanium alloys in aqueous electrolytes has been investigated. Therefore, a commercial titanium grade 5 (Ti90Al6V4) alloy and a self-produced Ti60Al40 alloy were compared. After preparation by arc melting and a heat treatment, an extensive characterization of the alloy by X-ray diffraction and energy-dispersive X-ray spectroscopy has been performed. The electrochemical behaviour of the alloys in different electrolytes was investigated using different techniques like linear sweep voltammetry and electrochemical impedance spectroscopy. An influence of the electrolyte composition and the titanium content of the alloy on the dissolution process could be observed. Higher titanium content of the alloy impedes the dissolution process. An increase of chloride ions in the electrolyte facilitates the dissolution. The results could be proved by an electrochemical machining (ECM) process in lab scale.