Work function measurements on (100), (110) and (111) surfaces of aluminium

Eastment, Robert; Mee, C. H. B.

doi:10.1088/0305-4608/3/9/016

Cited by 185 publications

(74 citation statements)

References 18 publications

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“…From the midst of simple metals, the face-dependent experimental data of work function only for low-index aluminium crystal-faces are available but they differ between each other in the trend of increasing of their values (see Table III). The trend of Eastman and Mee's [21] values is consistent with the argumentation given by Smoluchowski [22], while the trend of Grepstad et al [23] values is in complete disagreement with these arguments.…”

Section: Polycrystalline and Face-dependent Work Functionsupporting

confidence: 79%

Work Function of Simple Metals: Relation between Theory and Experiment

Wojciechowski

Bogdanów

1994

Acta Phys. Pol. A

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A variational calculation of the face-dependent work function with pseudopotential corrections employed has been performed. Critical analysis of the comparison between the calculated work function values and the experimental polycrystalline data is also given. The polycrystalline work function data may be treated as the mean low-index work function values and compared with the ones calculated. The use of the simple variational method and the Ashcroft pseudopotential for the description of metallic ions leads to good agreement between theory and experiment, and also enables to explain the increasing or decreasing tendency of work function values in different series of the simple metals.

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Section: Polycrystalline and Face-dependent Work Functionsupporting

confidence: 79%

Work Function of Simple Metals: Relation between Theory and Experiment

Wojciechowski

Bogdanów

1994

Acta Phys. Pol. A

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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%

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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“…Thus, we could calculate directly the electronic workfunction difference with the pure metal, measuring the difference between the vacuum level near the surface of the oxide film and the vacuum level near the surface of the metal. For the Al(111) surface, a calculated value of 4.1 eV was obtained, to be compared with the experimental value of 4.25 eV [40]. The first full metal layer under this Al interface layer is referred here with the index l = 1, then l = 2 represents the next underneath metal layer and l = 3 the third metal layer.…”

Section: Electronic and Charge Analysismentioning

confidence: 99%

“…Our periodic cells exhibit two different surfaces, the pure metal surface at the bottom and the oxide film at the top. Thus, we could calculate directly the electronic workfunction difference with the pure metal, measuring the difference between the vacuum level near the surface of the oxide film and the vacuum level near the surface of the [40].…”

Section: Electronic and Charge Analysismentioning

confidence: 99%

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

Cornette

Costa

Marcus

2017

Metals

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Abstract:We modelled with Density Functional Theory (DFT) an Al-Cu alloy covered with a passive film, with several Cu concentrations (from the limit of the isolated atom to the monolayer) at the interface with the oxide, as well as Guinier-Preston 1 (GP1) zones. At low (respectively high) concentration, Cu segregates in the first (respectively second) metal layer underneath the passive film. The Cu monolayer is the most stable configuration (−0.37 eV/Cu atom). GP1 zones were modelled, with a three-copper atom cluster in the alloy. The GP1 zone is slightly favoured with respect to the Cu monolayer under the oxide film. A low (respectively high) Cu concentration induces an electronic workfunction increase (respectively decrease) by 0.3 eV (respectively −0.4 to −0.6 eV) as compared to pure Al. In contrast, without oxide, Cu segregation at the Al surface induces no workfunction change at low concentration and an increase of 0.3 eV of the workfunction at high concentration. Thus, the presence of oxide modifies the expected tendency of workfunction increase by adding a more noble metal. For the studied models, no spontaneous electron transfer occurs to the O 2 molecule.

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Work function measurements on (100), (110) and (111) surfaces of aluminium

Cited by 185 publications

References 18 publications

Work Function of Simple Metals: Relation between Theory and Experiment

Work Function of Simple Metals: Relation between Theory and Experiment

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

DFT Modelling of Cu Segregation in Al-Cu Alloys Covered by an Ultrathin Oxide Film and Possible Links with Passivity

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