X-ray photoelectron spectroscopy on uranium oxides: a comparison between bulk and thin layers

Berghe, S. Van den; Miserque, F.; Gouder, T.; Gaudreau, B.; Verwerft, Marc

doi:10.1016/s0022-3115(01)00461-5

Cited by 43 publications

(35 citation statements)

References 18 publications

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“…14, 15,16 The work on the study of the electronic structure of uranium and its alloys [17][18][19][20][21] and oxides UO 2+x (x≤0 and x≥0) employed theoretical calculation results, [22][23][24][25][26][27][28][29][30][31][32][33][34] photoelectron spectroscopy (PES) [35][36][37][38][39][40][41] and X-ray photoelectron spectroscopy (XPS) widely. 38,[42][43][44][45][46][47][48][49][50][51][52][53][54][55] These techniques were used to study films on various substrates. [38][39][40][56][57][58] Determination of uranium oxidation state and sample's ionic composition employs the U 4f doublet split due to the spin-orbit interaction by ∆E sl (U4f)=10.8 eV.…”

Section: Introductionmentioning

confidence: 99%

XPS Study of Ion Irradiated and Unirradiated UO₂ Thin Films

et al. 2016

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XPS determination of the oxygen coefficient k O =2+x and ionic (U 4+ , U 5+ and U 6+ ) composition of oxides UO 2+x formed on the surfaces of differently oriented (hkl) planes of thin UO 2 films on LSAT (Al 10 La 3 O 51 Sr 14 Ta 7 ) and YSZ (yttria-stabilized zirconia) substrates was performed. The U 4f and O 1s core-electron peak intensities as well as the U 5f relative intensity before and after the 129 Xe 23+ and 238 U 31+ irradiations were employed. It was found that the presence of uranium dioxide film in air results in formation of oxide UO 2+x on the surface with mean oxygen coefficients k O in the range 2.07-2.11 on LSAT and 2.17-2.23 on YSZ substrates. These oxygen coefficients depend on the substrate and weakly on the crystallographic orientation.On the basis of the spectral parameters it was established that uranium dioxide films AP2,3 on the LSAT substrates have the smallest k O values, and from the XRD and EBSD results it follows that these samples have a regular monocrystalline structure. The XRD and EBSD results indicate that samples AP5-7 on the YSZ substrates have monocrystalline structure, however, they have the highest k O values. The observed difference in the k O values, probably, caused by the different nature of the substrates: the YSZ substrates provide 6.4% compressive strain, whereas (001) LSAT substrates result only in 0.03% tensile strain in the UO 2 films.129 Xe 23+ irradiation (92 MeV, 4.8 × 10 15 ions/cm 2 ) of uranium dioxide films on the LSAT substrates was shown to destroy both long range ordering and uranium close environment, which results in increase of uranium oxidation state and regrouping of oxygen ions in uranium close environment. 238 U 31+ (110 MeV, 5 × 10 10 , 5 × 10 11 , 5 × 10 12 ions/cm 2 ) irradiations of uranium dioxide films on the YSZ substrates were shown to form the lattice damage only with partial destruction of the long range ordering.3

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Section: Introductionmentioning

confidence: 99%

XPS Study of Ion Irradiated and Unirradiated UO₂ Thin Films

et al. 2016

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“…A broadened O 1s emission envelope (not shown), which could accommodate contributions from chemisorbed water, hydroxyl and carbonyl groups as well as oxides, was consistently observed for all samples before sputtering [13]. After sputtering, the O 1s emission collapsed into a relatively narrow and nearly symmetric peak, and the measured binding energies converged on a small range of values that are compatible with various oxides, including Cs 2 O, UO 2 and ZrO 2 [13,14].…”

Section: Resultsmentioning

confidence: 72%

“…Comparable results were obtained from the bottom end of the E23 element (both end cap and weld), with the most notable difference being a modestly enhanced abundance of uranium relative to the segregated fission products. Partial oxidation of uranium to the hexavalent state was indicated by the U 4f 7/2 binding energies measured at all types of locations before sputtering [13,14]. On average, the degree of oxidation was greatest on the welds and least on the end caps with the fuelsheath interface (both CANLUB layer and exposed sheath) at an intermediate level.…”

Section: Resultsmentioning

confidence: 99%

Microchemical study of high-burnup CANDU® fuel by imaging-XPS

Irving

Hocking

2008

Journal of Nuclear Materials

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“…At 25°the depth from which photoelectron are sampled is reduced by at least sin H ¼ 0:42 to about 2 nm, the top few monolayers. The nature and morphology of the uranium oxide proved to be very different in these two regions [10].…”

Section: X-ray Photoelectron Spectroscopy (Xps) Measurementsmentioning

confidence: 79%