Anisotropic work function of clean and smooth low-index faces of aluminium

Grepstad, J. K.; Gartland, P.; Slagsvold, B.J.

doi:10.1016/0039-6028(76)90187-4

Cited by 243 publications

(53 citation statements)

References 21 publications

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“…22 Besides, for the readers' reference, we list the available calculated and experimental work function data of all these pure metals in Table S1 as Supplementary Materials. For comparison, calculated 29 and measured 33,34 work functions for pure Al(111), (110) and (100) faces in the literature are also given in the table inserted in Fig. 5, Figure 5.…”

Section: Resultsmentioning

confidence: 99%

“…Work function of different crystal faces of pure metals (Mg, Zn, Al, Cu, Si) calculated in our work. Corresponding literature data for pure Al (calculated 29 and measured 33,34 ) are listed in the inserted table. showing a good agreement with our calculation. In our calculations, we used GGA-PW91 exchange-correlation functional, which gives a better agreement with the experimental data compared to GGA-PBE exchange-correlation functional used in that calculation.…”

Section: Resultsmentioning

confidence: 99%

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First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

Jin

Liu

Zhang

et al. 2017

J. Electrochem. Soc.

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This work presents a theoretical assessment of galvanic (relative) nobility of four intermetallic particles (IMPs), Al 2 Cu, Al 2 CuMg, Mg 2 Si and MgZn 2 , in aluminum alloys through work function calculation based on density functional theory (DFT). The concepts of work function, Volta potential and relative nobility are discussed with respect to the IMPs and aluminum matrix. The calculated Volta potentials are compared with reported experimental Volta potentials measured by scanning Kelvin probe force microscopy (SKPFM). Various crystal faces and terminal types are examined in the DFT calculation, showing that these two factors have a significant effect on the work function value. Considering the large divergence in the reported experimental data, the comparison shows a general agreement between the calculated and experimental Volta potential data for the investigated IMPs. The DFT calculations provide theoretical explanations for several experimental phenomena. The results demonstrate that DFT calculation is a valuable theoretical approach for assessment of the relative nobility of different phases in the alloys, providing complementary information to experimental data from SKFPM. Moreover, the implications of the calculated Volta potentials are discussed with respect to the corrosion potentials. The addition of various alloying elements into the aluminum (Al) matrix to improve mechanical performance of Al alloys may simultaneously increase their susceptibility to localized corrosion. This is mainly due formation of intermetallic particles (IMPs) that may trigger micro-galvanic corrosion along the interface between the IMPs and the alloy matrix.1 The potential differences between the IMPs and the matrix may result in localized dissolution of the matrix or dealloying of the IMP. 2The most common IMPs present in 2xxx and 7xxx series Al alloys include Al 2 CuMg (S-phase), Al 2 Cu (θ-phase), Al 7 Cu 2 Fe (β-phase), MgZn 2 (η-phase) and Mg 2 Si.3-5 IMPs containing Cu and Fe, such as Al 2 Cu. 6 and Al 7 Cu 2 Fe, 7 are considered to be cathodic with respect to the matrix, acting as local cathodes and thus promoting cathodic reactions such as oxygen reduction. In contrast, Mg-rich IMPs, such as Al 2 CuMg, are considered anodic relative to the matrix, resulting in selective dissolution and concomitant Cu-enrichment of the IMP.8 These localized corrosion events may eventually trigger other corrosion forms, such as stress corrosion cracking or intergranular corrosion.9 Therefore, micro-galvanic corrosion effects between IMPs and the Al matrix is considered to be of utmost importance for the overall service performance of Al alloys.In 1987, Stratmann started to use the Kelvin probe to investigate corrosion properties of metals under thin electrolyte films.10 His measurements revealed a linear relationship between Volta potential and corrosion potential of Cu, Zn, Fe and other metals. Later, the scanning Kelvin microprobe was developed and used for Volta potential measurements of several metals in humid atmospheres.11 Du...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

Jin

Liu

Zhang

et al. 2017

J. Electrochem. Soc.

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“…Therefore, in the case of p-polarized light where the polarization vector lies in the plane of incidence, this leads to emission currents strongly increasing with incidence angle. The effect has been observed on molybdenum 17 , silicon 16 , aluminum 18 , and recently on copper 19,20 . It is possible to rule out a dependency of this effect on a specific crystalline geometry, as the vectorial photoelectric effect was found to be similarly strong in single-crystal as well as polycrystal surfaces 19 , where randomly oriented crystal domains would average out any symmetry-related contributions.…”

Section: B the Vectorial Photoelectric Effectmentioning

confidence: 94%

The vectorial photoelectric effect under solar irradiance and its application to sun sensing

Hechenblaikner¹,

Ziegler

2014

Meas. Sci. Technol.

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Sun sensors are an integral part of the attitude and orbit control system onboard almost any spacecraft. While the majority of standard analogue sun sensors is based on photo-detectors which produce photo-currents proportional to the cosine of the incidence angle (cosine detectors), we propose an alternative scheme where the vectorial photoelectric effect is exploited to achieve a higher sensitivity of the sensed photo-current to the incidence angle. The vectorial photo-effect is investigated in detail for metal cathode detectors in a space environment. Besides long operational lifetimes without significant degradation, metal cathode detectors are insensitive to earth albedo, which may significantly reduce the errors affecting attitude measurements in low earth orbits. Sensitivity curves are calculated and trade-offs performed with the aim of optimizing the sensitivity whilst also providing currents sufficient for detection. Simple applications and detector configurations are also discussed and compared to existing designs.

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“…We further note that the theoretical anion fraction decreases when the experimental work function (W expt = 4.4 eV [39,40]) of the Al(100) surface is used in computing n a according to (15), rather than the theoretical work function W theor = 4 eV [ Figs. 16(c)-16(d)] we employed so far.…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

H−formation in collisions of hydrogen atoms with Al(100) surfaces

Obreshkov

Thumm

2013

Phys. Rev. A

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We theoretically investigate the electron transfer dynamics during the reflection of hydrogen atoms on an Al(100) surface for a wide range of collision energies below 6 keV. We find a nonmonotonic variation of the hydrogen-negative-ion fractions as functions of the projectile impact velocity due to nonadiabatic electron transfer. Our calculated anion fractions for projectiles scattered along high Miller-index crystal-surface directions are in good quantitative agreement with measured H − fractions for a wide range of exit velocities.

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Anisotropic work function of clean and smooth low-index faces of aluminium

Cited by 243 publications

References 21 publications

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications

The vectorial photoelectric effect under solar irradiance and its application to sun sensing

H−formation in collisions of hydrogen atoms with Al(100) surfaces

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