Angle‐resolved core‐level spectroscopy of Zr1Nb alloy oxidation by oxygen, water and hydrogen peroxide

Abstract

The initial oxidation of Zr1Nb alloy in oxygen, water and hydrogen peroxide at room temperature has been studied by angle-resolved x-ray photoelectron spectroscopy (ARXPS). The clean surface of alloy has been prepared either by scraping under ultrahigh (10 −10 mbar) vacuum or by argon ion sputtering.The four well-defined oxidation states of Zr were identified in the oxide films on Zr1Nb. The results of the ARXPS study were consistent with a layered structure of the oxide film, with zirconium dioxide in the outermost part of the film and suboxides in the inner region. The overall thickness of the incipient oxide layers ranged from 1.8 nm for the sputtered surface oxidized by oxygen, to 4.2 nm for the scraped surface oxidized in hydrogen peroxide. Mathematical analysis of the fitted Zr 3d spectra based on a layered structure model allowed us to estimate the thicknesses of individual suboxide layers. The population of suboxides as well as the binding energy of the Zr 3d electrons belonging to tetravalent zirconium were found to depend on the oxidizing agent and on the method used to clean the surface prior to oxidation. The amount of suboxides was much higher on the oxidized alloy surface cleaned by ion sputtering than on surfaces cleaned by scraping. The presence of zirconium hydride was observed in the spectra of Zr 3d electrons of the samples oxidized by water. The observed differences in binding energy of the Zr 3d component assigned to the Zr 4+ oxidation state are interpreted by differences in the structure of the dioxide layer.

Oxygen vacancies generated by Sn-doped ZrO2 promoting the synthesis of dimethyl carbonate from methanol and CO2

“…Aer deconvolution calculation of the Zr3d spectrum in the ZrO 2 catalyst, Zr3d can also be decomposed into 2 groups of peaks: Zr (4Àx)+ ($181.7 eV), ZrO 2 ($182.2 eV). 42,43 In Table 4, by calculating the ratio of the area of the Zr (4Àx)+ peak to the total area of the Zr (4Àx)+ and ZrO 2 peaks, the concentration ratio of Zr (4Àx)+ can be quantitatively estimated.…”

Preparation and Characterization of Zr–N-Codoped TiO<SUB>2</SUB> Nano-Photocatalyst and Its Activity Enhanced-Mechanism

“…From Figure 3(A), doublet peaks around at 181.5 and 183.9 eV were attributed to the Zr3d5/2 and Zr3d3/2, respectively, which arose from the doping Zr 4+ ions by substituting lattice titanium in doped TiO 2 sample, because the Zr3d5/2 peak falls between that for ZrO 2 (183.5 eV) 19 and metallic Zr (179 eV). 20 As seen from Figure 3(B), a single N peak at binding energy of 399.5 eV was observed, which was attributed to the presence of substitutional N in N Ti O bond, indicating that some lattice oxygen atoms were substituted by nitrogen.…”

Corrosion behavior of new quaternary ZrNbTiAl alloys in simulated physiological solution using electrochemical techniques and surface analysis methods

“…Analogously, the oxide films on Zr usually present a layered structure determined by the stoichiometry of different oxides that grow from the metallic substrate toward the outer surface in a sequence of increasing oxidation numbers, namely Zr2O/ZrO/Zr2O3/ZrO2 [1,58]:…”

“…Using Raman spectroscopy, Gomez Sanchez et al [59] and Farina et al [15] found that the oxide film formed spontaneously on Zr in the air mainly has a tetragonal structure of ZrO2, whereas the oxide films formed on Zr and Zr-2.5Nb alloy by anodization present mainly a monoclinic structure of ZrO2. In the case of the anodized samples from Zr and Zr-2.5Nb alloy, the ZrO2 monoclinic film incorporated a new phase identified as a Zr phosphate demonstrating the incorporation of phosphate ions from the electrolyte [15,58,59]. Although experimental data on the crystallography of passive films on Zr-based materials are scarce, from these few antecedents it can be argued that the crystallographic structure of such oxide films depends strongly on the oxidizing medium employed.…”

“…Bastl et al [58], using angle-resolved X-ray photoelectron spectroscopy (ARXPS), have shown that oxide films grown on Zr-1Nb alloy contain four oxidation states regardless of the oxidizing medium (namely oxygen, water, hydrogen peroxide). These characteristics are consistent with a layered structure of oxide films.…”