On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

Frankel, G. S.; Newman, R. C.; Jahnes, C.; Russak, M. A.

doi:10.1149/1.2220794

Cited by 124 publications

(98 citation statements)

References 12 publications

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“…When these tunnels are viewed or stop propagating then they appear bounded by (100) walls. This explanation supports the idea that dissolution of the substrate material dominates the pitting process rather than the nature of the oxide ®lms [23].…”

Section: Discussionsupporting

confidence: 82%

Electrochemical studies on single-crystal aluminium surfaces

Treacy

Breslin

1998

Electrochimica Acta

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AbstractÐThe electrochemical behaviour of single-crystal aluminium oriented in the (111), (110) and (100) directions in chloride-and indium-containing solutions was studied. It was found that the susceptibility of the single crystals to the onset of pitting attack in the chloride solution varied in the order (111)>(110)>(100). This was evident from pitting potential and induction time data, where the most noble pitting potential values and the longest induction periods were recorded for the (100) surface. This was explained in terms of dierences in the surface energy of (111), (110) and (100) planes. It was also found that cathodic reduction reactions (hydrogen evolution and oxygen reduction reactions) proceeded at a greater rate on the (100) surface. In addition, the time delay between the addition of indium ions to solution and the onset of activation of the immersed electrode by the indium species was shorter for the (100) surface. This was attributed to the more ecient incorporation of indium into the (100) lattice. #

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Section: Discussionsupporting

confidence: 82%

Electrochemical studies on single-crystal aluminium surfaces

Treacy

Breslin

1998

Electrochimica Acta

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“…The determination of thin film pit growth kinetics through the analysis of images of growing pits has indicated that a large portion of the higher pitting potential of these sputtered nonequilibrium Al alloys can be attributed to the ennoblement of the dissolution reaction. 18 To test whether the pit dissolution kinetics were affected by the base pressure, thin film pit growth experiments were performed in this study. As described in the experimental section, a sample surface was observed and recorded while the potential was controlled manually.…”

Section: Resultsmentioning

confidence: 99%

“…18,19 The thin film sample surface was viewed and recorded continuously using a video system. The sample was illuminated from above, which provided strong contrast between the black pitted region and the reflective unpitted region.…”

Section: Methodsmentioning

confidence: 99%

“…18 However, these sputtered Al alloys cannot be compared to the performance of bulk alloys because of the limited solubility of most of the alloying elements under equilibrium conditions achieved using standard casting of bulk samples. In this case, the improved corrosion properties can be attributed to the homogeneous microstructure containing supersaturated concentrations of alloying elements for the sputter-deposited samples, i.e.…”

Section: 9mentioning

confidence: 99%

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Effect of Vacuum System Base Pressure on Corrosion Resistance of Sputtered Al Thin Films

Frankel

Chen

Gupta

et al. 2014

J. Electrochem. Soc.

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Pure aluminum (Al) thin films were sputter deposited under conditions of variable base pressure of the deposition tool. The purpose of the study was to identify if the base pressure had a key influence on the electrochemical properties, namely corrosion resistance, of the Al deposits. The corrosion resistance was found to increase with increasingly high base pressure (i.e. lower quality vacuum). Potentiodynamic polarization experiments, pit growth studies, TEM and XPS were employed. From the results is posited that improved corrosion resistance is due to the presence of oxygen (O) being incorporated into the films during deposition resulting an O-containing (i.e. Al-O) alloy. This effect is important to identify because of the many reports in the literature of high pitting potentials for Al thin films, from studies with widely varying base pressure. Vacuum system base pressure was found to have a large effect on the corrosion resistance. A maximum base pressure in the low 10 −7 Torr range is recommended to minimize oxygen uptake into the film. Corrosion of thin film metal samples deposited by sputter deposition or evaporation has attracted considerable attention because of the technological applications of thin films in the electronics industry. From a research perspective, thin films also provide unique opportunities for studying fundamental aspects of the pitting phenomenon and also for the investigation of non-equilibrium alloy compositions. Many papers report an increased corrosion resistance of thin films relative to bulk alloy counterparts, often expressed as an increase in the pitting potential, E pit .1-11 Other researchers have found E pit for thin films to be similar to bulk alloys of a similar composition. 12,13Several different reasons for the improved corrosion resistance of thin films have been offered. Liu and coworkers proposed that the increase in pitting resistance of Ni-based alloy thin films resulted from the nanocrystalline microstructure of the films. [4][5][6][7] Regarding the role of grain size on corrosion resistance, both increases and decreases in corrosion resistance with decreasing grain size have been reported, 14 with the phenomenon being closely related to test environment.15 Because a fine grain structure has more reactive sites with respect to oxide formation and film ion conduction, the relative rates of reaction in a given environment might be altered. However, it is unlikely that grain size variation alone can explain the very noble values of E pit that have been reported for some pure metal thin film samples.Factors other than grain size have been reported to result in ennobled E pit values in thin film samples. 16 For alloys that pit at specific sites in a heterogeneous microstructure, such as MnS particles in stainless steel, improved homogeneity achieved by sputtering can certainly improve the corrosion performance. This chemical effect, as opposed to a structural effect, has been invoked by some as an important factor when evaluating sputtered stainless steel or Fe-Cr al...

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“…The overpotential deposition results in stable non-equilibrium alloy phase with uniform composition and structure. Furthermore, the non-equilibrium alloys exhibit similar chloride-induced pitting potentials as those prepared by physical non-equilibrium alloying methods such as rapid solidification, [16][17][18][19] sputter deposition, [20][21][22][23][24][25][26] and ion implantation. 27 Therefore, the electroplating of aluminum alloys from the Lewis acidic chloroaluminate IL is a possible low-cost alternative to conventional non-equilibrium methods for producing thin films of aluminum alloys.…”

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confidence: 99%

Electrodeposition of Al-W-Mn Ternary Alloys from the Lewis Acidic Aluminum Chloride−1-Ethyl-3-methylimidazolium Chloride Ionic Liquid

Tsuda

Ikeda

Imanishi

et al. 2015

J. Electrochem. Soc.

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The electrodeposition of non-equilibrium ternary Al-W-Mn alloys was examined in the Lewis acidic 66.7-33.3 m/o aluminum chloride-1-ethyl-3-methylimidazolium chloride (AlCl 3 -[C 2 mim]Cl) ionic liquid (IL). K 3 [W 2 Cl 9 ] and MnCl 2 were added to provide sources of W and Mn. The Al-W-Mn alloys were deposited on Cu wire substrates rotated at a fixed rate of 1000 rpm by using a dc galvanostatic method. The W content in the ternary Al-W-Mn alloys decreased with an increase in the deposition current density and was independent of the K 3 [W 2 Cl 9 ] and MnCl 2 concentrations in the plating solution. However, both the current density and the metal salt concentrations affected the Mn content of the ternary alloys. X-ray diffraction and composition analysis of the resulting Al-W-Mn deposits revealed the presence of an amorphous non-equilibrium alloy phase without chloride contamination. The chloride-induced pitting potential of the Al-W-Mn ternary alloys was found to be superior to that of the related binary alloys, Al-W and Al-Mn, indicating that the presence of two transition metal solutes has a beneficial additive effect on the corrosion resistance of Al. The many useful features and novel physical properties of ionic liquids (ILs), which are also called room-temperature or ambient-temperature molten salts, make them fertile media for future technologies.1-3 Thermodynamically, aluminum metal cannot be electrodeposited from aqueous solutions containing Al(III), because hydrogen is produced before the Al(III) can be reduced. However, Al can be deposited from aprotic, nonaqueous solutions, e.g., organic solvents containing aluminum salts and from chloroaluminate ILs. 4 However, all processes involving the electrodeposition of Al from organic solvents are based on volatile, flammable solvents and pyrophoric aluminum salts, greatly complicating large-scale aluminum plating operations. As a result, one of the fastest emerging technologies based on ILs is the electrodeposition of aluminum and its alloys from chloroaluminate ionic liquids. Although reactive with moisture, these ILs are virtually non-flammable and have negligible vapor pressure. Among the chloroaluminates, AlCl 3 -1-ethyl-3-methylimidazolium chloride (AlCl 3 -[C 2 mim]Cl) IL is under development for industrial-scale aluminum plating and for lab-scale aluminum alloy electrodeposition. mim]Cl IL. The processes leading to these alloys can be divided into underpotential and overpotential deposition. 5 The former alloys are deposited thermodynamically; i.e., their composition as a function of potential can be calculated from the Nernst equation.5 Al-Cu and Al-Ag alloys form by this underpotential mechanism. However, they tend to suffer from significant chloride contamination. The overpotential deposition results in stable non-equilibrium alloy phase with uniform composition and structure. Furthermore, the non-equilibrium alloys exhibit similar chloride-induced pitting potentials as those prepared by physical non-equilibrium alloying methods such as rapid * Elect...

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On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

Cited by 124 publications

References 12 publications

Electrochemical studies on single-crystal aluminium surfaces

Electrochemical studies on single-crystal aluminium surfaces

Effect of Vacuum System Base Pressure on Corrosion Resistance of Sputtered Al Thin Films

Electrodeposition of Al-W-Mn Ternary Alloys from the Lewis Acidic Aluminum Chloride−1-Ethyl-3-methylimidazolium Chloride Ionic Liquid

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