Auger (AES) and X-ray photoelectron spectroscopic (XPS) characterizations of electrochemically oxidized titanium are described. Surface oxides on thin (200-250 Å) vacuum deposited titanium films were formed under conditions of linear potential scan in 1 N KClO4, 1 N HClO4 and 1 N H2SO4. Current/voltage, capacitance/voltage and surface conductance/voltage relationships confirmed the irreversible formation of the surface oxide at thickness of 20-30 Å/V, for low applied potentials. Post moretem analysis of the thin films by AES and XPS indicated a mixture of metal and metal oxides (TiO2, Ti2O3, TiO) on each surface, with the higher oxide states predominating on the electrochemically oxidized films. Observation of the LIIIM2,3M4,5, N(E) signal shape in the Auger spectra of the potentially oxidized oxidized films showed a suboxide TiO-like surface rather than an TiO2 surface state. Deconvolution of the Ti(2p 1 2, 3 2) XPS spectra confirmed the coexistence of multiple oxidation states of Ti during electrochemical or atmospheric oxidation of the films. Ion sputtering of each surface was used to characterize the subsurface metal/metal oxide composition and to correlate the oxygen to metal atomic ratio with electrochemical pretreatment.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces