• Corrosion Science and Technology
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• v.8 no.3
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• pp.93-102
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• 2009

The direct-current electroetching of high purity aluminum in hot aqueous-chloride solution produces a high density of micrometer-wide tunnels whose walls are made up of the {100} planes and penetrate aluminum in the <100> directions at rates of micrometer per second. In the process of the alternating-current pitting of aluminum, cathodic polarization plays an important role in the nucleation and growth of the pits during the subsequent polarization. The direct-current tunnel etching and alternating-current etching of aluminum are basically related to the formation of poorly crystallized or amorphous passive films. If the passive film forms on the wall, a natural misfit exists between the film and the aluminum substrate, which in turn gives rise to stress in both the film and the substrate. Even though the amorphous films do not have directed properties, their stresses are influenced by the substrate orientation. The films on elastically soft substrate are likely to be less stressed and more stable than those on elastically hard substrate. The hardest and softest planes of aluminum are the {111} and {100} planes, respectively. Therefore, the films on the {111} substrates are most likely to be attacked, and those on the {100} substrates are least likely to be attacked. For the tunnel etching, it follows that the tunnel walls tend to consist of the {100} planes. Meanwhile, the tunnel tip, where active corrosion takes place, tend to be made of four closely packed {111} planes in order to minimize the surface energy, which gives rise to the <100> tunnel etching.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.13-20
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• 2014

In this paper, the effects of a nonionic surfactant on the etch uniformity and the etch profile during the wet-etching process of high-purity aluminum were investigated for the fabrication of uniform micropattern arrays. To improve the surface roughness of a high-purity aluminum plate, a mechanical lapping process and an electrolytic polishing process were used. After electrolytic polishing process, the surface roughness, Ra, of the high-purity aluminum plate was improved from $1.25{\mu}m$ to $0.02{\mu}m$. A photoresist was used as an etching mask during the aluminum etching process, where the mixture of phosphoric acid, acetic acid, nitric acid, a nonionic surfactant and water was used as the aluminum etchant. Different amounts of the Triton X-100 nonionic surfactant were added to the aluminum etchant to investigate the effect of a nonionic surfactant during the wet-etching process of high-purity aluminum. The etch rate and the etch profile were measured by an optical interferometer and a scanning electron microscope.

• Corrosion Science and Technology
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• v.10 no.1
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• pp.37-42
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• 2011

Aluminum was electrochemically etched in acid solution and the surface area was magnified by the formation of etch pits. Etched aluminum was covered with a compact and dense dielectric oxide film by anodization and applied to the aluminum electrolytic capacitor electrode. Capacitance of aluminum electrolytic capacitor is closely related with surface area, which depends on size and number of etch pits. Size of etch pits need to be controlled because inside of the pits can be buried by the formation of dielectric oxide film. In this work, the effect of ultrasound pretreatment on the aluminum etch pit formation and capacitance were investigated. Additionally, the relationship between the second etching effect on pit size and capacitance was studied.

• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.271-279
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• 1993

Experiments on electorchemical etching of aluminum foils with high cubic textures were carried out in this study. Etching behaviours and pit shapes with respect to various conditions of eletrochemical etching were in-vestigated. When HCl and NaCl solutions were used as electrolytes, the highest capacitanes were observed in solutions of 1MHCl and 5M NaCl. It was foundd that capacitance was improved by addition of H2SO4 to HCl so-lution which is considered to be due to the suppression of oxide film formation on the aluminum surface. The homogeneous distribution of each pits obtained in the HCl solution, while the degree of weight loss was lowest in the Nacl solution. The best etching properties in 1M HCl solution were obtained at the etching condi-tions of 0.15 A/$\textrm{cm}^2$, 150sec and$ 90^{\circ}C$.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.32-32
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• 1992

• Electrical & Electronic Materials
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• v.9 no.3
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• pp.291-297
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• 1996

The surface properties of AI(Si, Cu) alloy film after plasma etching using the chemistries of chlorinated and fluorinated gases with varying the etching time have been investigated using X-ray Photoelectron Spectroscopy. Impurities of C, Cl, F and O etc are observed on the etched AI(Si, Cu) films. After 95% etching, aluminum and silicon show metallic states and oxidized (partially chlorinated) states, copper shows Cu metallic states and Cu-Cl$_{x}$(x$_{x}$ (x$_{x}$ (1

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.485-490
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• 1994

The reactive ion etching characteristics of aluminum oxide films, prepared by PECVD, were investigated in the CCl4 plasma. The atomic chlorine concentration and the DC self bias were determined at various etching conditions, and their effects on the etch rate of aluminum oxide film were studied. The bombarding energy of incident particles was found to play the more important role in determining the etch rate of aluminum oxide rather than the atomic chlorine concentration. It is considered to be because the bombardment of ions or neutral atoms breaks the strong Al-O bonds of aluminum oxide to help activate the formation reaction of AlCl3 which is the volatile etch product.

• Journal of the Korean institute of surface engineering
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• v.22 no.2
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• pp.62-68
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• 1989

Pb2+ ino, added in ctching sohing, is electrodeposited on a alumiunm foil for electrolycic condenser to promote its capacitance. In addition, several factoral factors in etching process are varied to examine how they change the capacitance of the condenser. The capacitance of the condenser made of 0.1 ppm pb electrodeposited aluminum foil is enhanced about 20% than of conventional ane. It is thought out that the enhanement is the result of the act of PbO2, which existed for the conveting of electrodeposited Pb, as a promoter tunnel etching of aluminum foil.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.108-113
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• 2009

The mixing of two dissimilar aluminum alloys in friction stir welding (FSW) was investigated using etching. The results show that the materials from the retreating side mixed into the advancing side in rather narrow and elongated bands whereas the materials from the advancing side mixed into the retreating side in the form of thick bands and lobes. A computational method using smoothed particle hydrodynamics (SPH) is introduced as a way to properly describe the complex mixing behavior in FSW.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.53.2-53.2
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• 2010

In this study, we focused on our specialized electrode process for Si back-contact crystalline solar cell. It is different from other well-known back-contact cell process for thermal aspect and specialized process. In general, aluminum makes ohmic contact to the Si wafer and acts as a back surface reflector. And, silver is used for low series resistance metal grid lines. Aluminum was sputtered onto back side of wafer. Next, silver is directly patterned on the wafer by screen printing. The sputtered aluminum was removed by wet etching process after rear silver electrode was formed. In this process, the silver paste must have good printability, electrical property and adhesion strength, before and after the aluminum etching process. Silver paste also needs low temperature firing characteristics to reduce the thermal budget. So it was seriously collected by the products of several company of regarding low temperature firing (below $250^{\circ}C$) and aluminum etching endurance. First of all, silver pastes for etching selectivity were selected to evaluate as low temperature firing condition, electrical properties and adhesive strength. Using the nano- and micron-sized silver paste, so called hybrid type, made low temperature firing. So we could minimize the thermal budget in metallization process. Also the adhesion property greatly depended on the composition of paste, especially added resin and inorganic additives. In this paper, we will show that the metallization process of back-contact solar cell was realized as optimized nano-paste characteristics.