• Journal of the Korean institute of surface engineering
• /
• v.28 no.2
• /
• pp.101-109
• /
• 1995

Electroetching rates of $FeCl_3$ solution were increased according to increasing solution temperature. Activation energy of electroetching at Be'36 and 5A/$dm^2$ condition was 28.3Kcal and also, at Be'46 and 5A/dm$^2$ condition was 33.2Kcal. At Be'36 concentration of $FeCl_3$ solution, electroetching rate were more higher than at Be'46 concentration. Surfaces of etched grooves obtained at 8A/$dm^2$ or higher current density in 46 Be' concentration of $FeCl_3$ solution were observed to be flat and smooth owing to suppressing chemical etching reaction. Distinctly etched boundaries became to be appeared at 2A/$dm^2$ in Be'41 electroetching condition by differential effects. In case of applying 8A/$dm^2$ current density to Be'46 of $FeCl_3$ solution, etching depth were 4 times and side etching were 6 times more than chemical etching case respectively.

• Resources Recycling
• /
• v.15 no.2 s.70
• /
• pp.32-36
• /
• 2006

Magnesium has been used as light and functional material, and its demand is increasing as a material for automobile engine and for mobile phone or notebook PC case. Fused salt electrolysis and thermal reduction are regarded as main methods for the extraction of magnesium, and choice for the method is firstly according to raw material. In this study, magnesium metal is obtained by an electrolysis of magnesium chloride. Two types of fused salt mixtures were used as electrolyte and electrolyzed at 7V with a graphite anode having the same depth, and their results were compared with each other. A mixed salt of $KCl/NaCl/MgCl_2$ was the more effective than $KCl/NaCl/CaCl_2/CaF_2/MgCl_2$ in current efficiency through the experiments at $760^{\circ}C$. Purity of the prepared magnesium metal was above 98%. Some basic data for scale-up of the magnesium electrolysis equipment, which would be necessary for a commercialization, could be obtained.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.2
• /
• pp.169-175
• /
• 2016

The electrolyte added the chlorosulfuric acid ($HSO_3Cl$) as an additive was tested for the electrolyte in all-vanadium redox flow battery (VRFB) to increase the thermal stability of electrolyte. The electrolyte property was measured by the CV (cyclic voltammetry) method. The maximum value of a voltage and current density in the electrolyte added $HSO_3Cl$ was higher than that in the electrolyte non-added $HSO_3Cl$. The thermal stability of the pentavalent vanadium ion solution, which was tested at $40^{\circ}C$, increased by adding $HSO_3Cl$. The performances of VRFB using the electrolyte added and non-added $HSO_3Cl$ were measured during 30 cycles of charge-discharge at the current density of $60mA/cm^2$. An average energy efficiency of the VRFB was 72.5%, 82.4%, and 81.6% for the electrolyte non-added $HSO_3Cl$, added 0.5 mol of $HSO_3Cl$, and added 1.0 mol of $HSO_3Cl$, respectively. VRFB using the electrolyte added $HSO_3Cl$ was showed the higher performance than that using the electrolyte non-added $HSO_3Cl$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.58-61
• /
• 2002

SBT thin films were etched at different content of Cl$_2$in Cl$_2$/Ar plasma. We obtained the maximum etch rate of 883 ${\AA}$/min at Cl$_2$(20%)/Ar(80%). As Cl$_2$ gas increased in Cl$_2$/Ar plasma, the etch rate decreased. The maximum etch rate may be explained by variation of volume density for Cl atoms and by the concurrence of two etching mechanisms such as physical sputtering and chemical reaction with formation of low-volatile products, which can be desorbed only by ion bombardment. The variation of volume density for Cl, F and Ar atoms and ion current density were measured by the optical emission spectroscopy and Langmuir probe. To evaluate the physical damage due to plasma, X-ray diffraction and atomic force microscopy analysis carried out. After etching process, P-E hysteresis loops were measured by ferroelectric workstation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.10
• /
• pp.814-819
• /
• 2010

Porous carbon electrodes with wooden materials are manufactured by molding carbonized wood powder. Electrical properties of the interface for electrolyte and porous carbon electrode are investigated from viewpoint of NaCl electrolyte concentration, capacitance and complex impedance. Density of porous carbon materials is 0.47~0.61 g/$cm^3$. NaCl electrolytic absorptance of the porous carbon materials is 5~30%. As the electrolyte concentration increased, capacitance is increased and electric resistance is decrease with electric double layer effect of the interface. The electric current of the porous carbon electrode compared in the copper and the high density carbon electrode was improved on a large scale, due to a increase in surface area. The circuit current increased as the distance between of the porous carbon electrode and the zinc electrode decreased, due to increase in electric field. Experimental results indicated that the current properties of galvanic cell could be improved by using porous carbon electrode.

• Journal of the Korean Ceramic Society
• /
• v.38 no.3
• /
• pp.218-224
• /
• 2001

Yttria-stabilized zirconia (YSZ) films were deposited with varying temperatures of ZrCl$_4$between 250~55$0^{\circ}C$ with YCl$_3$and the substrate at 100$0^{\circ}C$. Nanoamperes per square centimeter of the electric current were measured in the reactor during deposition and the current increased with increasing evaporation temperature of ZrCl$_4$. The zirconia nanometer size clusters were captured on the grid membrane near the substrate during the CVD process and observed by transmission electron microscopy (TEM). The deposition rate decreased with increasing evaporation temperature of ZrCl$_4$. A cauliflower-shaped structure was developed at 25$0^{\circ}C$ then gradually changed to a faceted-grain structure above 35$0^{\circ}C$. Dependence of the growth rate and the morphological evolution on the evaporation temperature of ZrCl$_4$was approached by the charged cluster model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05c
• /
• pp.71-74
• /
• 2003

Photoconductor for direct detection fiat-panel imager present a great materials challenge, since their requirement include high X-ray absorption, ionization and charge collection, low leakage current and large area deposition, CdTe is practical material. We report studies of detector sensitivity, That is an CdTe with $5{\mu}m$ thickness on glass. That is hybrid layer of depositting ZnS:AgCl phosphor with $100{\mu}m$ on CdTe. The leakage current of hybrid is similar to it of a-Se, but photocurrent is larger than a-Se. Both of them have high spatial resolution, but hybrid has higher sensitivity than a-Se at comparable bias voltage.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.2
• /
• pp.275-280
• /
• 2015

In this study, the current-voltage curves for stainless steel in the triethanolamine(TEA) solution was measured using the conventional three electrodes of cyclic voltammetry. Stainless steel as working electrode, Ag/AgCl electrode as reference electrode and Pt wire as counter electrode were used respectively. As a result, the C-V characteristics of stainless steel were to be for an irreversible process due to the oxidation current from cyclic voltammogram, using triethanolamine solutions. Effective diffusivity of corrosion inhibitors was decreased with increasing concentration. And the concentration of 0.5 N $NaClO_4$, $2.5{\times}10^{-3}M$ TEA solution when the corrosion inhibition effect is most great, and 1.5 N $NaClO_4$, $1.0{\times}10^{-3}M$ TEA solution, the lowest corrosion inhibition effect.

• Journal of Environmental Science International
• /
• v.19 no.9
• /
• pp.1143-1152
• /
• 2010

The purpose of this study is to degradation of Rhodamine B (RhB, dye) and N, N-Dimethyl-4-nitrosoaniline (RNO, indicator of the electro-generation of OH radical) in solution using boron doped diamond (BDD) electrode. The effects of applied current (0.2~1.0 A), electrolyte type (NaCl, KCl, and $Na_2SO_4$) and electrolyte concentration (0.5~3.0 g/L), solution pH (3~11) and air flow rate (0~4 L/min) were evaluated. Experimental results showed that RhB and RNO removal tendencies appeared with the almost similar thing, except of current. Optimum current for RhB degradation was 0.6 A, however, RNO degradations was increased with increase of applied current. The RhB and RNO degradation of Cl type electrolyte were higher than that of the sulfate type. The RhB and RNO degradation were increased with increase of NaCl concentration and optimum NaCl dosage was 2.5 g/L. The RhB and RNO concentrations were not influenced by pH under pH 7. Optimum air flow rate for the oxidants generation and RhB and RNO degradation were 2 L/min. Initial removal rate of electrolysis process was expressed Langmuir - Hinshelwood equation, which is used to express the initial removal rate of UV/$TiO_$2 process.

• Journal of Environmental Science International
• /
• v.17 no.6
• /
• pp.581-589
• /
• 2008

This study was carried out to evaluate the effect of water quality of cooling tower on Legionella pneumophila disinfection using Ru/Ti electrode. The influences of parameters such as pH, turbidity, $CaCO_3$ and TOC were investigated using laboratory scale batch reactor. Oxidants such as free Cl, $ClO_2,\;H_2O_2\;and\;O_3$ were measured. The results showed that all of the water quality parameters of cooling tower had deteriorated disinfection of Legionella pneumophila. When the turbidity, $CaCO_3$ and TOC was increased, oxidants which was generated during electrolysis was decreased. pH, free Cl, $ClO_2\;and\;H_2O_2$ concentration were decreased with the increase of pH, whereas $O_3$ concentration was increased with the increase of pH. The order of effect of water quality on the disinfection performance for Legionella pneumophila was turbidity > $CaCO_3$ > TOC > pH. To obtain the safety standard (1000 CFU/L), the simultaneous increase current and NaCl dosage was needed.