XPS depth profiling of oxide scales of stainless steels formed in high‐temperature aqueous conditions
ABSTRACT In this work, we studied the oxide scales of AISI 304 and AISI 316 stainless steels formed under high-temperature aqueous conditions using X-ray photoelectron spectroscopy (XPS) together with sputter depth profiling. Two samples of SS 304 and 316 were prepared by exposing them to water at 300 °C containing 100 ppm boric acid and 7 ppm lithium hydroxide in an autoclave.In the case of sputtering with 3 keV argon ions, the elemental distribution as a function of the sputtering time was obtained. The formation of two oxide layers was observed—one mainly iron-based on top, and a second at a greater depth, consisting mainly of chromium-iron oxides. The depth scale of the profiles was calibrated by measuring the oxygen profile using Rutherford backscattering spectroscopy (RBS). On the basis of the distribution of the three oxidised alloying constituents (Fe, Cr, Ni) with respect to depth and elemental state, a relative increase of Fe2+ at the surface was found, while the chromium was depleted at the surface and Cr3+ tended to increase at the oxide/substrate interface. In order to estimate possible ion-beam-induced effects due to the ion sputtering, the profiles were compared to the computer-simulated ones obtained by a dynamic TRIM computer code. The simulations included only collisional effects during the sputtering process. Copyright © 2006 John Wiley & Sons, Ltd.
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ABSTRACT: The oxide film on 304 stainless steel exposed to the hydrothermal environments at 573.15K up to 20days without/with 10ppb Zn injection has been investigated ex situ by X-ray photoelectron spectroscopy (XPS). ZnFe2O4 and ZnCr2O4 were found to be formed in the oxide film at the initial stage of immersion by substitution reaction between Zn2+ and Fe2+, and ZnCr2O4 became dominant after long-term immersion. The calculations of potential-pH diagrams, solubilities and crystallographic features of spinels have been done to evaluate the oxide film structure and the inhibition mechanism caused by Zn injection.Corrosion Science 10/2011; 53(10):3337-3345. · 3.69 Impact Factor
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ABSTRACT: The influence of Zn injection on established film on 316 L stainless steel exposed to high temperature water up to 4000 h at 573.15 K has been investigated by SEM, EDX, XPS, XRD and Raman spectrum. It was found that the initial water chemistry played a key role on the characteristics of surface oxide films. The films become more compact with increasing exposure time in the Zn-injection solution. The thermodynamics and kinetics of existing stable oxides have been considered to evaluate evolving procedure of the established film. A modified model for oxide films structure is proposed and discussed.Corrosion Science 12/2012; 65:136–144. · 3.69 Impact Factor
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ABSTRACT: A computer program is described which allows fully three-dimensional dynamic collisional simulations of ion irradiation effects in particular in nanosystems. The program is based on the well-known TRIDYN code which describes dynamic modifications along one dimension. In a computational volume composed of fixed and equisized voxels, local atomic density changes due to ion implantation or recoil relocation are relaxed to constant predefined atomic volumes. This is accomplished by interaction with neighboring voxels and by material transport towards and away from the surface. Arbitrary initial system shapes and elemental distributions can be defined as well as a wide range of irradiation conditions including non-uniform beam profiles. The paper addresses details of the involved algorithms and discusses potential artifacts with respect to surface sputtering, broadening of compositional profiles, and surface contours. It demonstrates the capabilities of the program by examples of focused ion beam erosion, self-organized surface pattering, and ion implantation and sputter-shaping of nanostructures.Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 03/2014; 322:23–33. · 1.19 Impact Factor