Articles you may be interested inThin oxide-free phosphate films of composition formed on the surface of vanadium metal and characterized by xray photoelectron spectroscopyValence band x-ray photoelectron spectroscopic investigation of surface cleanliness of aluminum metal and its alloys J.This paper reports the results of a continuing study focused on preparing novel surface chemistries on metal surfaces. In this paper we report how it is possible to prepare oxide-free titanium metal surfaces protected by a film consisting of phosphate. The surface is prepared by electrochemical treatment in an anaerobic cell which allows electrochemistry to be conducted on samples located in a vacuum system attached to an x-ray photoelectron spectrometer. When a clean metal surface is subjected to electrochemical treatment in aqueous orthophosphoric acid an oxide-free phosphate film can be formed on the metal which is stable on subsequent air exposure. Compositional variations were found with potential and other factors. Identical electrochemical treatment of as-received titanium metal yielded samples that had a surface consisting largely of oxide. The chemical composition of these surface films was studied by core level and valence band x-ray photoelectron spectroscopy. Valence band photoemission interpreted by band structure calculations was found to be especially effective in understanding subtle differences in surface chemistry, enabling the clear identification of phosphate ͑being able to distinguish between orthophosphate and metaphosphate films͒ and its distinction from surface oxide. Valance band spectra calculated from band structure calculations for TiO, Ti 2 O 3 , TiO 2 , TiC, TiPO 4 , and TiP 2 O 7 are reported.