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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, an attempt was made to use certain features observed in the AES spectra to correlate Fe and Cr MNN peak shapes with the chemical state of the corresponding element.
22 citations
TL;DR: An experimental and theoretical study of phosphorus electronic structure based on high energy resolution X-ray emission spectroscopy was performed and clear correlation between energy position of the Kα emission line and the phosphorus formal oxidation state as well as DFT-calculated number of valence electrons is obtained.
Abstract: An experimental and theoretical study of phosphorus electronic structure based on high energy resolution X-ray emission spectroscopy was performed. The Kα and Kβ emission spectra of several phosphorus compounds were recorded using monochromatic synchrotron radiation and megaelectronvolt (MeV) proton beam for target excitation. Measured spectra are compared to the results of ab initio quantum chemical calculations based on density functional theory (DFT). Clear correlation between energy position of the Kα emission line and the phosphorus formal oxidation state as well as DFT-calculated number of valence electrons is obtained; measured energy shifts are reproduced by the calculations. Chemical sensitivity is increased further by looking at the Kβ emission spectra probing directly the structure of occupied molecular orbitals. Energies and relative intensities of main components are given together with the calculated average atomic character of the corresponding molecular orbitals involved in transitions.
22 citations
TL;DR: In this article, a black micro arc oxidation coating was prepared on 2A12 aluminum alloy in the electrolyte based on Na2SiO3, Na3PO4, NaOH, EDTA-2Na and NH4VO3 as additives.
22 citations
TL;DR: The effect of argon ion etching on surface composition and chemical state was studied using α-Fe2O3, Na2CrO4, tungsten oxides and some nickel alloys as target materials and employing the XPS technique as discussed by the authors.
22 citations
TL;DR: In this article, the authors investigated the electrical resistivity as a function of temperature of the Sn-0.7Cu solder alloy with the addition of Fe and Bi. The electrical resistivities were characterized by the four-point probe method, which revealed the presence of Sn in Sn2+, Sn4+ and state of metallic Sn.
Abstract: In this paper, we investigated the electrical resistivity as a function of temperature of the Sn–0.7Cu solder alloy with the addition of Fe and Bi. The electrical resistivity were characterized by the four-point probe method. Apparent change in electrical resistivity was witnessed by the addition of both Fe and Bi. At room temperature, the electrical resistivity was found to be increased with the addition of Fe, as well as a further increase with the addition of Bi. Fe and Bi modified Sn–0.7Cu alloys also experienced the similar increasing trend when they were subjected to higher temperatures within the range of 300–423 K. Chemical state of Sn was analyzed by means of X-ray photoelectron spectroscopy (XPS). The results revealed the presence of Sn in Sn2+, Sn4+ and state of metallic Sn. With the addition of Fe & Bi, a substantial decrease was observed in the atomic percent of the Sn4+ chemical state. X-ray diffraction (XRD) was performed on the alloys. The XRD pattern showed disturbance in the 2 theta values with the addition of Bi. The disturbance confirmed the presence of stress and imperfections in the crystal lattice. Field emission scanning electron microscope (FESEM) micrographs revealed the formation of the FeSn2 intermetallic compound with the addition of Fe. However, the addition of Bi promotes the formation of solid solution and goes into primary β-Sn dendrites. Microstructural changes, shifts in the chemical state of Sn and a disturbance in the XRD peaks resulting from the addition of Fe and Bi have been correlated to the variation in electrical resistivity.
22 citations