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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 article, a microhardness of maximum 20 GPa was achieved, affected by carbon content, by the way of its incorporation into the hexagonal turbostratic lattice as well as by the crystallite size and its texture.
22 citations
TL;DR: In this article, it was shown that in the embrittled state these elements are segregated to within the first few monolayers of the high angle boundaries and the segregation is reversible and can be removed by heating at temperatures above the embrittlement range, whilst still within the α field (that is > 600 °C).
Abstract: PREREQUISITES for reversible temper embrittlement of steel1 are the presence of a trace impurity2 (Sb, Sn, As or P) and a major alloying element3,4 (Ni, Cr or Mn). Auger electron spectroscopy (AES) demonstrated that in the embrittled state these elements are segregated to within the first few monolayers of the high angle boundaries5,6. The segregation is reversible and can be removed by heating at temperatures above the embrittlement range, whilst still within the α field (that is > 600 °C). It has been postulated7 that the segregation behaviour can be explained using equilibrium thermodynamics. It is proposed that the trace impurities interact more strongly with the major alloying elements than the Fe matrix and hence the chemical potential of the system is reduced by segregation to the high angle boundaries with the formation of bi-dimensional complexes (such as Ni3Sn2) Mn3P and Cr3P). No experimental evidence is available for the existence of such complexes. AES gives no information regarding the chemical bonding of the segregants but it has been shown8, using X-ray photoelectron spectroscopy (XPS), that the segregated Mn on embrittled fracture surfaces of a 2% Mn steel is in a different chemical state to that on unembrittled surfaces. We report here preliminary results from a specially prepared 3% Ni steel, doped with 119Sn, which were obtained using Mossbauer spectroscopy to monitor changes in the nearest-neighbour atoms of the Sn atoms as a function of heat treatment in the temper embrittlement temperature range.
22 citations
TL;DR: In this paper, the structure and surface morphology evolution were investigated by an X-ray diffraction (XRD) and an atomic force microscopy (AFM) and a scanning electron microscopy(SEM) respectively.
22 citations
02 Mar 1998-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: A crystal spectrometer system was arranged at an external proton beam to measure the K X-ray spectra for various compounds of Al, Si, P and S at atmospheric pressure as discussed by the authors.
Abstract: A crystal spectrometer system was arranged at an external proton beam to measure the K X-ray spectra for various compounds of Al, Si, P and S at atmospheric pressure. Satellite structures of the Ks spectra caused by molecular-orbital splittings are well resolved. The results demonstrate that in situ chemical state analysis has now been possible using this in-air high-resolution PIXE system.
22 citations
TL;DR: In this article, the matrix effect in two-element Zr-containing alloys using TOF-SIMS was investigated and it was observed that Zr ionization efficiency is over four times higher in the Si matrix than in the Cu matrix and over two times higher when compared to the results obtained in the Al matrix.
Abstract: The matrix effect, i.e. the dependence of element ion yield on the surrounding chemical state, is very often considered as a negative and limiting factor in elemental characterization. In fact, it is the main reason making Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) a non-quantitative technique as element ionization efficiency can span over several orders of magnitude depending on the matrix. Despite that, even small chemical variations of an experimental setup can cause interpretation of TOF-SIMS depth profiles a challenging task. However, the sensitivity of element ionization to the neighboring atoms can also be very beneficial as ion yields can be enhanced in the presence of particular species such as oxygen, cesium, water and fluorine. In this work, we make an attempt to estimate the matrix effect in two-element Zr-containing alloys using TOF-SIMS. The Zr ionization efficiency as well as its response to the surface and interface contaminants was investigated depending on Al, Si and Cu matrices. It was observed that Zr ionization efficiency is over four times higher in the Si matrix than in the Cu matrix and over two times higher when compared to the results obtained in the Al matrix.
22 citations