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Chemical state

About: Chemical state is a research topic. Over the lifetime, 2378 publications have been published within this topic receiving 78183 citations.


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TL;DR: In this paper, the thermal release of oxygen from a high-Tc compound, YBa2Cu3O7, and subsequent changes of the chemical states were examined by a thermal desorption method and X-ray photoelectron spectroscopy.
Abstract: Thermal release of oxygen from a high-Tc compound, YBa2Cu3O7, and the subsequent changes of the chemical states were examined by a thermal desorption method and X-ray photoelectron spectroscopy. The former gives a spectrum with two peaks around 480°C and 700°C. The latter suggests that the 480°C peak corresponds to oxygens in the one dimensional CuO chains in the unit cell of the lattice, and the 700°C peak to one of the oxygens above and below the central copper atom. With the release of these oxygens, the copper atoms in the compound change from a pure Cu2+ state into a Cu1+ dominant state.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the characterization of Au 49 Cu 26. 9 Ag 5.5 Pd 2.3 Si 16.3 amorphous ribbons produced by melt spinning is reported.
Abstract: New multinary amorphous materials, based on gold, that can be produced in bulk form due to their high glass-forming tendency, were discovered recently. However little is known about their corrosion properties. In the present study, the characterization of Au 49 Cu 26 . 9 Ag 5.5 Pd 2.3 Si 16.3 amorphous ribbons produced by melt spinning is reported. Their corrosion properties were tested by incubating the samples in artificial sweat and by monitoring the changes in surface structure by SEM and XRD. Before incubation, the surface of the samples was amorphous and flat, characterized only by microfeatures due to the liquid contact with the wheel during quenching. After treatment with artificial sweat, the formation of nanosized crystallites of Au on the sample surface was observed. The surface chemical composition of both sides of the ribbon samples was investigated by XPS. Atomic concentration and chemical states of constituent elements before and after the incubation in artificial sweat were determined. The depth profiling of both sides ofthe samples was carried out by using Ar ion sputtering combined with cyclic XPS measurements. The segregation of Si on one side of the samples and the changes of chemical composition, caused by the treatment in artificial sweat, were revealed.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the position in the plots of different classes of compounds is discussed, and it is suggested that the energy involved in the electron transfer 2p53d10L is similar to the screening energy in the metallic state.
Abstract: Cu- and Zn-containing compounds are characterised making use of the Wagner Auger parameter and of the so-called chemical state plots to obtain information on the relative initial-state charge distributions and on the relative extra-atomic relaxation energy. The position in the plots of different classes of compounds is discussed. To explain the constancy of the Auger parameter for Cu(II) compounds and metallic Cu, it is suggested that the energy involved in the electron transfer 2p53d10L is similar to the screening energy in the metallic state.

9 citations

Journal ArticleDOI
TL;DR: In this article, a mass spectrometer attached with a molybdenum Knudsen cell was used to measure the partial vapor pressures and chemical activities of principal components of SUS 304L austenitic steel.
Abstract: The vaporization of SUS 304L stainless steel was studied by using a mass spectrometer attached with a molybdenum Knudsen cell. The partial vapor pressures and chemical activities of principal components of SUS 304L austenitic steel were determined in the temperature range of 1,300–1,430 K (for Fe and Cr each) and 1,070–1,230 K (for Mn). Activity coefficients, partial free energies of mixing and excess partial free energies of the components Mn, Fe and Cr were computed from the measured partial pressures and chemical activities. The thermodynamic functions obtained are discussed especially in regard of the chemical state of Cr at the surface of SUS 304L stainless steel.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the chemical states of epitaxial PbZrxTi1-xO3 films were investigated by an X-ray photoelectron spectroscopy as a function of the gamma-ray doses.
Abstract: The chemical states of epitaxial PbZrxTi1-xO3 films were investigated by an X-ray photoelectron spectroscopy as a function of the gamma-ray doses. An anomalous behaviour was observed in Pb4f states, and a core level of Pb4f shifts towards a higher binding energy at 50 kGy and towards a lower binding energy at 200 kGy. The behaviour can be explained by a radiation induced reduction of PbO to metallic Pb. The metal-insulator-metal electrodes were fabricated by lithography, and the current-voltage characteristics were measured. A negative differential resistance (NDR) was observed in the leakage currents at room temperature. A higher current and disappearance of NDR characteristics were found in the 200 kGy irradiated samples, which further confirms the presence of metallic Pb.

9 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202326
202249
202184
202089
201987
201894