GI-EDIXS for the Determination of the Oxidation State of Titanium Surface Films

J. ROBLEDO; J. J. LEANI; FABIANA OLIVA; H. J. SÁNCHEZ

Conferencia; TXRF 2019; 2019

Universidad de Girona

Titanium is a transition element which is widely used in technological devices, from medical prosthetic implants to active material for Li-ion batteries. As titanium is a major constituent element in those systems, requires a proper characterization [1-4]. One of the most serious problems in titanium analysis is to properly discriminate Ti(III) from Ti(IV). In this work we use the EDIXS technique [5] in grazing incidence conditions, to analyze different titanium compounds in order to determine the oxidation state of Ti in different surface nanolayers. The analyzed surfaces were prepared by electrochemical anodization on metallic titanium substrates with and without further cathodization stages. Different anodic potentials, electrolyte composition and cathodization condition were applied, thus surface films of titanium oxides or (hydr)oxides of different chemical characteristic were obtained.The measurements were carried out at the Brazilian Synchrotron Light Source (LNLS, Campinas) in the D09B beamline and at the IAEA end-station of the XRF-beamline at Elettra Sincrotrone Trieste (Italy). A grazing incidence angle scan was performed to study the chemical environment of Ti at different depths of the samples. Several samples with different cathodization treatments were studied.In order to discriminate changes in the titanium chemical state of the formed surface films, a Multivariate Method as Principal Component Analysis was applied on the RIXS spectra.The results show that it is possible to perform a depth profiling analysis of oxidation states by mean of the EDIXS technique. These analyses are quite difficult or even impossible to achieve by conventional spectroscopic techniques.The surface films present a very specific in-depth distribution regarding the chemical environment of the studied element.