• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.100-104
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• 1996

This paper describes the characteristics of micro-burr formation in the cross hatch and deburring in honed surfaces. Two types of micro-burrs formed in the cross hatch were defined as upper edge burr (type A) and side edge burr (type B). The size of micro-burrs were measured for the honed surfaces of several cross hatch angle. Deburring mechanism and system using magneto-electrolytic process including the abrasive pad for mechanic deburring effects together were introduced. Deburring experiments and analysis were carried out to confirm the effectiveness of the deburring process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.19-32
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• 2010

Electrolytic reduction technology is essential for the purpose of adopting pyroprocessing into spent oxide fuel as an alternative option in a back-end fuel cycle. Spent fuel consists of various metal oxides, and each metal oxide releases an oxygen element depending on its chemical characteristic during the electrolytic reduction process. In the present work, an electrolytic reduction behavior was estimated for voloxidized spent fuel based on the assumption that each metal-oxygen system is independent and behaves as an ideal solid solution. The electrolytic reduction was considered as a combination of a Li recovery and chemical reactions between the metal oxides such as uranium oxide and the produced Li metal. The calculated result revealed that most of the metal oxides were reduced by the process. It was evaluated that a reduced fraction of lanthanide oxides increased with a decreasing $Li_2O$ concentration. However, most of the lanthanides were expected to be stable in their oxide forms. In addition, a semi-empirical model for describing $U_3O_8$ electrolytic reduction behavior was proposed by considering Li diffusion and a chemical reaction between $U_3O_8$ and Li. Experimental data was used to determine model parameters and, then, the model was applied to calculate the reduction yield with time and to estimate the required time for a 99.9% reduction.

• Tribology and Lubricants
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• v.37 no.6
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• pp.208-212
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• 2021

Chemical mechanical polishing (CMP) is a key technology used for the global planarization of thin films in semiconductor production and smoothing the surface of substrate materials. CMP is a type of hybrid process using a material removal mechanism that forms a chemically reacted layer on the surface of a material owing to chemical elements included in a slurry and mechanically removes the chemically reacted layer using abrasive particles. Sapphire is known as a material that requires considerable time to remove materials through CMP owing to its high hardness and chemical stability. This study introduces a technology using electrolytic ionization and ultraviolet (UV) light in sapphire CMP and compares it with the existing CMP method from the perspective of the material removal rate (MRR). The technology proposed in the study experimentally confirms that the MRR of sapphire CMP can be increased by approximately 29.9, which is judged as a result of the generation of hydroxyl radicals (·OH) in the slurry. In the future, studies from various perspectives, such as the material removal mechanism and surface chemical reaction analysis of CMP technology using electrolytic ionization and UV, are required, and a tribological approach is also required to understand the mechanical removal of chemically reacted layers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.776-779
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• 2003

To reduce the storage space of spent fuel used at the atomic power plants in the over the world, the uranium elements contained in the spent fuel is being extracted and effectively stored. For this, the spent fuel are oxidized and deoxidized. In this study, it is produced the heat-resisting methods about the spent fuel management technology research and test facility for the spent fuel waste for spent fuel minimized. The first considered processes in the facility are the electrolytic metal reduction reactor process. Since the electrolytic metal reduction reactor is operated at the high temperature range, we have to consider the heat-resisting methods for the devices. For the heat-resisting methods, we have searched and analyzed technical reference for the heat-resisting methods. We have calculated thermal stress and strain of each devices by the commercial analysis software, ANSYS. D.S. It is experimented for inspecting confidence rate of analysis results. By using the results, we have analyzed the problems of parts and determined the heat-resisting material, commercial parts, and the size of parts and O-ring. Based on these results, it is produced the heat-resisting methods of magnesia filter, cathode, and reactor for the electrolytic metal reduction reactor.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.1-6
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• 1997

This research was conducted in the laboratory to investigate an alternative of Copper(Cu) removal from an heavymetal wastewater using the electrochemical precipitation(ECP) process. The ECP unit consisted of an electrolytic cell made of Titanium plate and Steel plate representing anode and cathode. The DC power source applied to the ECP unit had electrical potential(E) of 50$\pm$ 1V, respectively. The synthetic wastewater used in the experiments contained Cu in the 10 mg/l concentration and the electrode separation were 2, 3, 4 cm and the initial pH were 3, 6, 9, 12, and electrolytic concentration were 0.005, 0.0125, 0.025, 0.0375 mole, and the real heavymetal wastewater used in the experiments. From the experiment for removal efficiency according to pH variation, the low pH area doesn't give the coagulation effect by Ti(OH)$_4$ because process interfere with the coagulation and oxidation reaction, therefore the optimum pH was 4-7. The removal rate was 97.75% after the lapse of 30 minutes when copper concentration and electrolytic concentration were respectively 10 mg/l and 0.025 mole. The removal rate was 96.41% after the lapse of 30minutes when the real heavymetal wastewater used. The optimum consumption of power showed 27KWh/m$^3$ when copper concentration, electrolyte concentration and cell potential were respectively 10 mg/l, 0.025 mole and 50$\pm$ 1 Volt.

• Journal of the Korean institute of surface engineering
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• v.30 no.3
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• pp.191-201
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• 1997

Non-passivated electrolytic tinplates withour conventinal chemical treatment self-oxidize in ambient atmosphere to from yellow stain on the outermost surface during the long-term storage. The degree of yellowness of the stain increased linerly with the oxide thickness due to the interfeefence color of the $SnO_2$ Even though the thickness of the oxide layer was very thin, less than 100$\AA$ , it exerts an undesirable influence on the can-making processes, particularly the stripping behavior after ironing. Investigations were carried out on the morphologies of the coating layer, the changes in oxide thickness during successive can-making processes and the averge friction coefficients with the different oxide thinkness. These oxide layers were broken up and distributed within the bulk tin coating during the ironing process. This redistribution of the oxide layer prvented smooth pressing-aside of the tin coating layer, resulting in an increase in the ironing friction coefficient. As the friction was increased, the residual stress along the can wall thinkness(i.e., the hoop stress) was also increased. Due to both the oxibe layer accumulation, which increased the friction coefficient, and the hoop stress, can stripping efficiency without roll-back is reduced.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.250-258
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• 2023

Ceramic oxide layer was formed on the surface of high silicon aluminum alloy by using PEO (plasma electrolytic oxidation) process. The microstructure of the oxide layer was analyzed using scanning electron microscopy (SEM) and x-ray diffraction patterns (XRD). The high silicon aluminum alloy prior to PEO process consists of Al, Si and Al₂Cu phases in XRD analysis, whereas Al₂Cu phase selectively disappeared after PEO treatment. Considerable decrease of relative intensity in most of peaks in XRD results of the high silicon aluminum alloy treated by PEO process was observed. It may be attributed to the formation of amorphous phases after PEO treatment. The corrosion behavior of the high silicon aluminum alloy treated by PEO process was investigated using electrochemical impedance spectroscopy (EIS) and other electrochemical techniques (i.e., open circuit potential and polarization curve). Electroanalytical studies indicated that the high silicon aluminum alloy treated by PEO process shows greater corrosion resistance than that untreated by PEO process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.59-64
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• 1998

We need to achieve th mass product through methods of higher efficient, higher precise manufacturing process than those of existing precision abrasive machining. Thus, this study is to develop mirror-like surface machining technique of outer diameter of the piston pin by the compound magneto-electrolytic abrasive polishing system. The procedure of machining is followed as first, fulfill the pre-processing by cylindrical grinder, second, complete mirror-like surface by the method of magneto-electrolytic abrasive polishing used CBN non-woven abrasive pads. In this study, it was found that the best suitable conditions of mirror-like surface polishing were that the electrode density was 0.1A/$\textrm{cm}^2$, the applied pressure 1.5kgf/$\textrm{cm}^2$, the feed rate 0.5mm/rev, and the rotoation velocity of workpiece 80rpm, and that the surface roughness was reduced in this conditions.

• Journal of the Korean institute of surface engineering
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• v.41 no.6
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• pp.308-311
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• 2008

Oxide layers were prepared on Al2021 alloys substrate under a hybrid voltage of AC 200 V (60 Hz) combined with DC 260 V value at room temperature within $5{\sim}60\;min$ by plasma electrolytic oxidation (PEO). An optimized aluminate-fluorosilicate solution was used as the electrolytes. The surface morphology, thickness and composition of layers on Al2021 alloys at different reaction times were studied. The results showed that it is possible to generate oxide layers of good properties on Al2021 alloys in aluminate-fluorosilicate electrolytes. Analysis show that the double-layer structure oxide layers consist of different states such as ${\alpha}-{Al_2}{O_3}$ and ${\gamma}-{Al_2}{O_3}$. For short treatment times, the formation process of oxide layers follows a linear kinetics, while for longer times the formation process slows down and becomes a steady stage. During the PEO processes, the average size of the discharge channels increased gradually as the PEO treatment time increased.

• Journal of Korea Foundry Society
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• v.43 no.5
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• pp.223-229
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• 2023

In this study, STS316L produced by a double-melting process involving vacuum induction melting (VIM) and vacuum arc remelting (VAR) was subjected to extrusion and drawing to form a tube and was subsequently electrolytic polished (EP). The grain size of the obtained STS316L without EP was approximately 55 ㎛, with no difference found after EP. The thickness of the EP layer was measured by AES and TEM, showing values of approximately 10 nm and 15 nm, respectively. After EP, the Cr/Fe and CrO/FeO ratios of the passive layer increased from 1.48 to 1.62 and from 2.15 to 2.26, respectively, while the surface roughness decreased significantly from 0.255 to 0.024 ㎛. Consequently, the corrosion rate decreased in both NaCl and HCl solutions after the EP process. Additionally, the amounts of eluted Cr and Fe ions were reduced from 1.2 to 0.8 ppb and 10.3 to 0.8 ppb, respectively. Furthermore, polarization tests revealed that STS316L treated with EP required a lower current density to reach a passive state, indicating that corrosion behavior was retarded.