Formation of potentially protective oxide-free phosphate films on titanium characterized by valence band x-ray photoelectron spectroscopy

Abstract

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.

Photoelectron spectroscopic studies of the formation of hydroxyapatite films on titanium pretreated with etidronic acid

“…The details are shown in Table . The separation between the middle binding energy and lower binding energy features is 1.6 eV, which is the same as the separation between Ti‐O of TiO 2 and OH ‐ of Ti(OH) 4 (and/or hydroxyoxides) . The three peaks from high to low binding energy has area ratio 2.36 : 1 : 1.66.…”

“…The core and valence band spectra of titanium metal and titanium alloys have been reported by numerous workers. The core and valence band XPS data for the titanium as received is shown in Fig.…”

“…In a series of papers, we have shown how oxide‐free phosphorus‐containing films can be formed on metals. These films have the potential to provide corrosion protection and the formation of biocompatible surfaces as well as a substrate for attaching other surface films.…”

Investigation of thin-oxide-free protective coatings on chromium and 316L stainless steel formed by treatment with etidronic acid

“…[1][2][3][4][5][6][7][8][9] In this work, we report how the use of etidronic acid ͓1-hydroxyethylidene-1,1-diphosphonic acid ͑hydroxyethyl diphosphonate or HEDP͔͒ can form such films, providing an example of how an organophosphorus acid can form thin-oxide-free films in addition to the films previously reported for phosphorus acids. [1][2][3][4][5][6][7][8][9] In this work, we report how the use of etidronic acid ͓1-hydroxyethylidene-1,1-diphosphonic acid ͑hydroxyethyl diphosphonate or HEDP͔͒ can form such films, providing an example of how an organophosphorus acid can form thin-oxide-free films in addition to the films previously reported for phosphorus acids.…”

Interfacial interactions of polymer coatings with oxide-free phosphate films on metal surfaces

“…The focus of the experimental work will be the use of valence band photoemission, which we have already shown to be effective in distinguishing between phosphate and oxide, [1][2][3][4][5] and in the identification of subtle chemical differences. We report the results of two photon sources; x-ray light provides information at a greater depth than UV light allowing us to nondestructively ''profile'' through the interface region.…”