• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.90.1-90
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• 1998

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.170.2-170.2
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• 2008

• Journal of Welding and Joining
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• v.32 no.3
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• pp.27-33
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• 2014

This paper presents a brief summary on a relatively new plasma aided electrolytic surface treatment process for light metals. A brief discussion regarding the advantages, principle, process parameters and applications of this process is discussed. The process owes its origin to Sluginov who discovered an arc discharge phenomenon in electrolysis in 1880. A similar process was studied and developed by Markov and coworkers in 1970s who successfully deposited an oxide film on aluminium. Several investigation thereafter lead to the establishment of suitable process parameters for deposition of a crystalline oxide film of more than $100{\mu}m$ thickness on the surface of light metals such as aluminium, titanium and magnesium. This process nowadays goes by several names such as plasma electrolytic oxidation (PEO), micro-arc oxidation (MOA), anodic spark deposition (ASD) etc. Several startups and surface treatment companies have taken up the process and deployed it successfully in a range of products, from military grade rifles to common off road sprockets. However, there are certain limitations to this technology such as the formation of an outer porous oxide layer, especially in case of magnesium which displays a Piling Bedworth ratio of less than one and thus an inherent non protective oxide. This can be treated further but adds to the cost of the process. Overall, it can be said the PEO process offers a better solution than the conventional coating processes. It offers advantages considering the fact that he electrolyte used in PEO process is environmental friendly and the temperature control is not as strict as in case of other surface treatment processes.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.31-39
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• 2017

The emission quantity of nitrous oxide is second largest among non-$CO_2$ greenhouse gas in Korea. In this study, we investigated loss rate of nitrous oxide which was filled in PVF and Al-PE bag as time goes on. Concentrations of tested samples were about 25 ppmv, 50 ppmv, 75 ppmv prepared by standard reference gas. In case of all experiments, loss rate of PVF bag was higher than Al-PE bag. After 18 days, loss rate of PVF bag was from 29.7% to 38.6% while Al-PE bag was from 21.7% to 23.7%. Especially the differential growed bigger when initial concentration of $N_2O$ in PVF bag was lower. And we also studied the effect of cock opening/closing procedures on loss rate. Prepared samples in experimental group were analyzed several times for 20 days and samples in control group were analysed only 1 time after 20 days. The experimental results showed that cock opening/closing procedures appeared to have little impact on loss rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.277-283
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• 2009

In this paper, aluminum doped zinc oxide (ZnO:Al) thin films on plastic substrate such as poly carbonate (PC), polyethylene terephthalate (PET) were prepared by RF magnetron sputtering method for flexible solar cell applications. Effects of the sputter pressure on the structural, electrical and optical properties were investigated. The crystallinity and the degree of the (002) orientation were deteriorated with increasing the sputter pressure. When the sputter pressure was higher, the conductivity of ZnO:Al films was improved because of the high carrier concentration and the Hall mobility. High quality ZnO:Al films with resistivity as low as $1.9{\times}10^{-3}{\Omega}-cm$ and the optical transmittance over 80 % in the visible region have been obtained on PC substrate at 2 mTorr.

• Journal of the Korean institute of surface engineering
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• v.53 no.2
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• pp.53-58
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• 2020

In this study, we developed plasma electrolytic oxidation (PEO) process for aluminum 7075 alloy to improve the corrosion and mechanical properties. The electrolyte consists of potassium hydroxide and sodium silicate. Additionally, sodium stannate was added into the electrolyte to investigate its effect on PEO film formation. Titanium was used as the counter electrode. Plasma generation voltage reduced from 300V to 150 V by adding 4 g/L of sodium stannate. The thin oxide films were observed by SEM(Scanning Electron Microscopy)/EDS (Energy Dispersive Spectroscopy) for quantitative and qualitative analyses. XRD (X-ray diffraction) and XRF (X-ray Fluorescences) analyses were also carried out to identify oxide layer on aluminum 7075 surface. Vicker's hardness test was performed on the PEO-treated aluminum 7075 surface.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.68-68
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• 2008

There are several methods for oxide coating on metals, such as aluminum or carbon nanotubes(CNTs). Usually CVD method is introduced for various oxide coating on CNTs. Another method is electrochemical method which use potential-pH diagram for oxide coating on metal or CNTs. In this experiment, electrochemical coating parameter for oxide coating on aluminum template modified by acids and hydrogen peroxide ($H_2O_2$) were examined. SEM micrographs displayed clearly $Ni(OH)_2$ coating on template. For confirmation of electrochemical method application to EDLC electrode material fabrication, EDS spectrum was analyzed.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.609-614
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• 2014

We fabricated amorphous zinc tin oxide (ZTO) transparent thin-film transistors (TTFTs). The effects of Al electrode on the mobility and threshold voltage of the ZTO TTFTs were investigated. It was found that the aluminum (Al)-ZTO contact decreased the mobility and increased the threshold voltage. Traps, originating from $AlO_x$, were assumed to be the cause of degradation. An indium tin oxide film was inserted between Al and ZTO as a buffer layer, forming an ohmic contact, which was revealed to improve the performance of ZTO TTFTs.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.756-762
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• 1997

The experiment was carried out to fabricate alumina membrane which has a cylindrical pore structure by anodizing aluminium plate in sulfuric acid solution with the electrochemical technique. The aluminium plate for anodizing was prepared by the pretreatment process such as chemical, electro-polishing and thermal treatment. The pore size distribution and the film thickness of alumina membrane were investigated by the implementation of scanning electron microscope(SEM) and BET method. The results show that the oxide film has a geometrical structures like a Keller model and that the membrane has a uniform pore distribution. The pore size and the oxide film thickness are dependent on the anodizing process variables such as the electrolyte concentration, the reation temperature and the anodizing current density.

• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.272-277
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• 2010

We investigated the life time characteristics of OLED device with aluminium oxide ($AlO_x$) passivation film on glass substrate and polyethylene terephthalate (PET) substrate by RF magnetron sputtering for the transparent barrier film applied to flexible OLED device. Basic buffer layer was determined as $Alq_3$(500 nm)-LiF(300 nm)-Al(1200 nm), and the most suitable aluminium oxide ($AlO_x$) film have been formed when the partial volume ratio of oxygen was 20% and the sputtering power was 100 watt and the minimum thickness of buffer was $2\;{\mu}m$. $AlO_x$/epoxy hybrid film was also used as a effective passivation layer for the purpose of improving life time characteristics of OLED devices with the glass substrate and the plastic substrate. Besides, the simultaneous deposition of $AlO_x$/epoxy film on back side of PET could result in better improvement of life time.