AVS 47th International Symposium
    Material Characterization Wednesday Sessions
       Session MC-WeM

Paper MC-WeM3
Formation of Potentially Protective Oxide-free Phosphate Films On Titanium Characterized by Valence Band X-ray Photoelectron Spectroscopy

Wednesday, October 4, 2000, 9:00 am, Room 207

Session: Methods of Data Analysis
Presenter: P.M.A. Sherwood, Kansas State University
Authors: J.A. Rotole, Kansas State University
K. Gaskell, Nottingham Trent University, UK
A. Comte, Ecole Nationale Superieure de Chimie de Clemont-Ferrand, France
P.M.A. Sherwood, Kansas State University
Correspondent: Click to Email
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 foil in atmosphere 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 films) and its distinction from surface oxide.@footnote 1@ @FootnoteText@ @footnote 1@ This work was funded by the National Science Foundation under grant CHE-9421068.