0000000000445595
AUTHOR
Sandrine Zanna
showing 6 related works from this author
Initial Surface Film on Magnesium Metal. A Characterization by X-ray Photoelectron Spectroscopy (XPS) and Photocurrent Spectroscopy (PCS)
2007
Abstract A detailed investigation of the initial film grown on mechanically polished Mg electrodes has been carried out by ex situ X-ray Photoelectron Spectroscopy (XPS) and in situ Photocurrent Spectroscopy (PCS), allowing to reach a detailed picture of the passive layer structure. The XPS data show that the films formed soon after mechanical treatment and immersion in aqueous electrolyte have a bilayer structure, consisting of an ultra-thin MgO inner layer (∼2.5 nm) and a Mg(OH) 2 external layer. The thickness of the Mg(OH) 2 layer is a function of immersion time and solution temperature. After mechanical treatment and immersion in aqueous solution at room temperature, the MgO/Mg(OH) 2 la…
Photoelectrochemical and XPS characterisation of oxide layers on 316L stainless steel grown in high-temperature water
2015
Passive films on AISI 316L stainless steel were grown by exposure in high temperature (300 °C and 150 bar) water. X-ray photoelectron spectroscopy was employed to study their composition as a function of immersion time. A photoelectrochemical investigation, supported by electrochemical and impedance measurements, allowed to get information on the solid-state properties of the investigated layers. The experimental results suggest the formation of a stratified layer with an outer iron-rich layer and an inner Cr-rich oxide layer, whose relative thickness and composition are dependent on the immersion time.
The influence of surface treatment on the anodizing of magnesium in alkaline solution
2011
Abstract The mechanism of magnesium anodizing after mechanical polishing or HF pickling was studied. X-ray Photoelectron Spectroscopy and Photocurrent Spectroscopy were employed to characterize both the initial films formed on Mg soon after surface treatments and the anodic films grown in strongly alkaline solutions. Electrochemical and capacitance measurements were performed in order to study the oxidation process and to check if the kinetic of growth fits the Mott–Cabrera high field model. From Tafel plots it was possible to estimate the activation distance, while the simulation of the barrier layer growth as a function of the potential at high scan rate allowed to estimate the other kine…
Influence of post-treatment time of trivalent chromium protection coating on aluminium alloy 2024-T3 on improved corrosion resistance
2019
Abstract Low corrosion protection performances of Trivalent Chromium Process (TCP) coatings with reference to Chromium Conversion Coatings (CCC) deposited on aluminium alloys can be overcome by application of post-treatment processes. This work shows the effect of post-treatment bath (containing hydrogen peroxide and lanthanum salt) on the chemical composition, structure and the corrosion performances of TCP coating deposited on AA 2024-T3 aluminium alloy. Different times of post-treatment bath were applied on the TCP coating and the samples were analyzed by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Glow Discharge-Optical Emission …
Effect of High Temperature Oxidation Process on Corrosion Resistance of Bright Annealed Ferritic Stainless Steel
2017
The corrosion resistance of stainless steels is determined by the thickness, structure, composition and electronic properties of the oxide layers grown on their surface and isolating the metallic substrate from the environment. In the present work, ex situ XPS (X-Ray Photoelectron Spectroscopy) and ToF-SIMS (Time of Flight Secondary Ions Mass Spectrometry) have been combined to in situ PCS (PhotoCurrent Spectroscopy) in order to perform an integrated physicochemical characterization of surface oxide films grown on bright annealed ferritic stainless steel (AISI 434) as-received and after thermal post-treatment in air. The surface oxide film on as-received samples has a bilayer structure with…
Passivation-Induced Physicochemical Alterations of the Native Surface Oxide Film on 316L Austenitic Stainless Steel
2019
Time of Flight Secondary Ion Mass Spectroscopy, X-Ray Photoelectron Spectroscopy, in situ Photo-Current Spectroscopy and electrochemical analysis were combined to characterize the physicochemical alterations induced by electrochemical passivation of the surface oxide film providing corrosion resistance to 316L stainless steel. The as-prepared surface is covered by a ~2 nm thick, mixed (Cr(III)-Fe(III)) and bi-layered hydroxylated oxide. The inner layer is highly enriched in Cr(III) and the outer layer less so. Molybdenum is concentrated, mostly as Mo(VI), in the outer layer. Nickel is only present at trace level. These inner and outer layers have band gap values of 3.0 and 2.6-2.7 eV, respe…