Comparative Study on Chemical Stripping of Titanium Oxide Films Formed on Titanium Alloy

Two methods for stripping of anodic oxide films formed on titanium alloys Ti-6.5Al-1Mo-1V-2Zr without hydrofluoric acid or fluoride were studied: i using hydrogen peroxide with sulfuric acid and ii using hydrogen peroxide with sodium hydroxide. The morphologies and microstructures of the oxide films before and after stripping were compared by SEM and Raman spectroscopy. The surface topography and roughness of the samples were detected by AFM. The results show that the oxide films can be stripped both by the two methods and the stripping process is affected by the microstructure of the matrix material obviously. β or platelet α phases are more affected by the solution i while globular α phase is preferentially dissolved by the solution ii. The surface stripped by solution ii is flatter than that by solution i. Compared to solution i, solution ii presents better environmental friendly result and lower cost.