Physical and chemical properties of stepped surfaces

Wagner, H.

doi:10.1007/bfb0048920

Cited by 41 publications

(12 citation statements)

References 105 publications

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“…Variation of the atomic density can differently change the surface states in the oxide and ewf. 35 Thus, the effect of the surface roughness due to plastic deformation on the potential had to be studied.…”

Section: Resultsmentioning

confidence: 99%

Effect of Mechanical Stress on the Properties of Steel Surfaces: Scanning Kelvin Probe and Local Electrochemical Impedance Study

Назаров

Vivier

Thierry

et al. 2017

J. Electrochem. Soc.

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The influence of mechanical stress on the electrochemical properties of ferritic steel SAE 1008 and austenitic stainless steel 301LN was studied using Scanning Kelvin Probe and Localized Electrochemical Impedance Spectroscopy (LEIS) techniques. The probeworking electrode Volta potential difference was mapped in situ under load. It was found that the influence of elastic deformation on the potential was small. Plastic deformation decreased the potential of steel by 150-300 mV, whereas the relaxation of the load from the plastic domain increased the Volta potential. However, some locations, which can contain residual stress, remained at low potential. The pre-strained surfaces were characterized by X-ray Photo Electronic Spectroscopy and by Atomic Force Microscopy. Distribution of the capacitance across strained and strain-free surfaces was studied by LEIS in boric/borate electrolyte. The plastic stress increases the capacitance and decreases the ability of the steels to passivate the surface indicating that emerging of pile-ups of dislocations create defective oxide films. Stress corrosion cracking (SCC) is a well-known complex corrosion process caused by the combination of stress and corrosion, which can lead to wear, cracking or fatigue failures. In many cases, the residual stress from plastic deformation or wear accelerates the corrosion rate.1 In the classic film rupture model, tensile stress breaks the passive film creating anodic locations at the bottom of the crack, 2,3 which propagates through an activation/passivation process. This model was developed to the "slip dissolution-film rupture model" pointing out the importance of formation of dislocations and metal dissolution through dislocation slip lines.3,4 The slip dissolution-film rupture model of crack advance was discussed in details previously. 5 This model can predict the crack growth rate for the stainless steels, nickel alloys, and low-alloy steels in high temperature water. 6 The effect of the yielding on the rate of dissolution of many metals was found to be much pronounced in comparison with the influence of elastic deformation. 7 The dissolution rate showed a marked rise at the beginning of the plastic region that is asymptotic with increasing strain. Similar effects of plastic deformation on the anodic current during dissolution were also found for stainless steels.8 To explain this mechanical-electrochemical effect, both the increase of dissolution rate at slip edges and dislocations, and the increase of surface roughness from plastic deformation were pointed out.8 On the other hand, the selective slip dissolution can be ascribed to the local excess of Gibbs potential, 7,8 thus contradicting earlier works. Hoar 9 has shown that both enthalpy and entropy of activation were not significantly altered by cold work, which meant that the free energy of activation for anodic reaction should remain almost constant. A calorimetric study 10 showed that residual energy from cold work was less than 7 calories per gram without any significant impact on ...

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Section: Resultsmentioning

confidence: 99%

Effect of Mechanical Stress on the Properties of Steel Surfaces: Scanning Kelvin Probe and Local Electrochemical Impedance Study

Назаров

Vivier

Thierry

et al. 2017

J. Electrochem. Soc.

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“…For example, the work functions of bulk transition metal surfaces are known to be crystal face dependent, with "rough" high index or kinked surfaces generally possessing lower IPs than "smooth" surfaces [45,46]. The CSD model is based purely on electrostatic arguments and thus cannot take into account any differences between the surface of the bulk metal and the "surfaces" of clusters.…”

Section: Ip=wf+2rmentioning

confidence: 99%

Photoionization studies of transition metal clusters: Ionization potentials of ScnO (n=5−36)

Yang

Knickelbein

1994

Z Phys D - Atoms, Molecules and Clusters

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Abstract. The photoionization efficiency (PIE) spectra and ionization potentials are reported for scandium cluster monoxides (Sc,O, n = 5-36). As found for other transition metal clusters, strong dependence of ionization potential on cluster size is found for small clusters, with the ionization potentials of larger clusters decreasing relatively smoothly with increasing size. The IPs are 0.6 0.8 eV lower than that predicted by conducting spherical droplet model.

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“…[1][2][3][4][5][6] However, low-energy electron diffraction (LEED) investigations of stepped surfaces, such as (211), are a particularly difficult problem. The Si (211) surface has been investigated for over 20 years, but the conclusions 7-9 are inconsistent; specifically they do not agree with the results of recent scanning tunneling microscopy (STM) investigations [10][11][12][13][14][20][21][22] demonstrating the intractability of the problem. A consistent picture of the changing surface as a function of temperature can be achieved through the combined use of LEED and STM.…”

Section: Introductionmentioning

confidence: 90%

“…21 We can extend his theory by analyzing the limiting case as the vicinal angle is increased to a stepped surface, that is, we consider (211) structures as extreme cases (19.47°in ½ 111 direction) of a vicinal (111) surface. The LEED pattern consists of terrace-and-ledge surface patterns.…”

Section: Theorymentioning

confidence: 98%

The structure of the Si (211) surface

Fulk

Sivananthan

Zavitz

et al. 2006

Journal of Elec Materi

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Silicon (211) has been proposed as an alternative substrate for CdTe/HgCdTe molecular beam epitaxial growth. Silicon has a clear advantage over other substrates because of its low cost, high strength, and thermal-expansion coefficient, which matches that of the silicon readout integrated circuit. The (211) orientation has been shown to yield high-quality CdTe and HgCdTe/CdTe layers over other orientations. The reconstruction and faceting of the Si (211) surface is poorly understood despite the importance of the (211) orientation. The results of low-energy electron diffraction (LEED) studies have been contradictory, and their conclusions are inconsistent with recent scanning tunneling microscopy (STM) studies. LEED and STM images were used to determine the most probable Si (211) surface facet structure as a function of annealing temperature. Samples annealed at a high temperature (i.e., . 1260°C) allowed the formation of ordered LEED spot patterns as opposed to the typically reported ½ 111 streaks. The pattern in the ½0 11 direction gave a consistent 23 (7.68 Å ) reconstruction.

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Physical and chemical properties of stepped surfaces

Cited by 41 publications

References 105 publications

Effect of Mechanical Stress on the Properties of Steel Surfaces: Scanning Kelvin Probe and Local Electrochemical Impedance Study

Effect of Mechanical Stress on the Properties of Steel Surfaces: Scanning Kelvin Probe and Local Electrochemical Impedance Study

Photoionization studies of transition metal clusters: Ionization potentials of ScnO (n=5−36)

The structure of the Si (211) surface

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