• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.5
• /
• pp.671-677
• /
• 1999

This study has been performed to investigate REW(relative electrode wear) in condition of vari-ous pulse-on duration using the copper and graphite electrode with change of the electrode size on the heat treated STD11 which is extensively used for metallic molding steel with the EDM. The results obtained are as follows; a) Graphite has much benefits than copper electrode when rapid machining is done without electrode wear, b) Neative REW result from the electrode that is very liable attach to decomposition carbide c)Increasing of machining time cause to increase wear length of the copper electrode and decrease wear length of the graphite electorde d)The more pulse-on duration copper electrode has the less REW. e) The edge portion of the electorde wears remarkably at the beginning of machining,.

• Electrical & Electronic Materials
• /
• v.9 no.8
• /
• pp.806-812
• /
• 1996

I-V characteristics of ground electrode fabricated using an aluminium scrap are presented. We fabricated several shapes of aluminium scraps and aluminium electrodes. The results show that the current of aluminium electrode increased linearly by the voltage increase. AC breakdown voltage of copper plate electrode was higher than that of aluminium electrode. AC breakdown current of aluminium electrode was higher than that of copper plate electrode. As applied voltage increased, grounding resistance of aluminum electrode decreased linearly.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.3
• /
• pp.28-35
• /
• 2016

Forging operations are non-stationary processes occurring because of indirect pressure, generally, under conditions of three-dimensional stress and deformation. Furthermore, due to friction and the constraints of die geometry, deformation is not homogeneous. Material flow and deformation are largely determined by the shape of the tools. It is well known that net-shape forging can improve the mechanical strength of the final product as well as reduce material waste. Oxygen-free copper that is used for electrical and electronic components has excellent electrical and thermal conductivity. Oxygen-free copper parts have a low productivity in cutting process. Thus, the forging process is performed in order to improve the low productivity in cutting process. The forging of oxygen-free copper for electrode body parts was modeled using finite element simulation and forging experiments that were conducted for producing electrode body parts at room temperature. In order to reduce the cost of cutting products, the forging was performed in a closed cavity to obtain near-net or net-shape parts.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.1
• /
• pp.147-150
• /
• 2014

Copper ink has been prepared by mixing copper(II) formate and 2-ethyl-1-hexylammonium bicarbonate (EHABC) to overcome some weak points such as aggregation and degradation of copper nano-type ink. Ink was coated on glass substrate and calcined at $110^{\circ}C$ to $150^{\circ}C$ to generate electrically conductive copper film under two different atmospheres such as nitrogen gas and gaseous mixture of formic acid and methanol. The lowest resistivity of $1.88{\mu}{\Omega}{\cdot}cm$ of copper film was obtained at $150^{\circ}C$ in gaseous formic acid condition. The long-term resistivity shows to increase from $1.88{\mu}{\Omega}{\cdot}cm$ to $2.61{\mu}{\Omega}{\cdot}cm$ after one month.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.6
• /
• pp.809-815
• /
• 1998

This study has been performed to investigate MRR(metal removal rate) surface roughness with various pulse-on duration using the copper and graphite electrode according to the electrode size on the heat treated STD 11 which is extensively used for metallic molding steel in the EDM. The results obtained are as follow ;a)MRR increases a lot when pulse-on duration is 100 $\mu{s}$ or less but MRR has little difference with pulse-on duration of 100 $\mu{s}$ or more b) According to the increase of Pulse-on duration the large the electrode size the more MRR c) Safe discharge is needed to make maximum of MRR and the metallic organization must be complicated for discharge induction. d) Actual machining time is longer than theoretical machining time at the short pulse-on duration because of skin effect of current. e) Graphite electrode needs the larger electric discharge energy than copper electrode to remove remained chips completely.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.11
• /
• pp.721-726
• /
• 2015

In this study, the properties of C-V degradation for thermal conductivity silicone rubber sample which is attached by copper-copper, copper-aluminum, aluminum-aluminum on upper-side and under-side has been measured at temperature of $80^{\circ}C{\sim}140^{\circ}C$. The results of this study are as follows. In case the frequency is increased, it found that the electrostatic capacity increased with increasing temperature to $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$ regardless of kind of electrode. It found that the electrostatic capacity increased with becoming high temperature range of frequency regardless of kind of electrode. This result is considered to be caused by thermal absorption on the thermal conductivity silicone rubber sample. It found that the electrostatic capacity decreased with increasing temperature and frequency. This result is considered to be caused by molecular motion of C-F radical or OH radical.

• Journal of Sensor Science and Technology
• /
• v.32 no.6
• /
• pp.352-356
• /
• 2023

The integration of bioelectronic devices with the skin is a promising strategy for personalized healthcare monitoring and diagnostics. On-skin bioelectrodes hold great potential for the real-time tracking of physiological parameters. However, persistent challenges of stability and reliability have instigated exploration beyond conventional noble metals. This study focuses on the ionic passivation and oxidation dynamics of copper-based on-skin thin-film bioelectrodes. Through parylene chemical vapor deposition, we harness a controlled thin film of parylene insulation to counter the intrinsic susceptibility of copper to oxidation in the ionic environment. The results represent the relationship among the parylene insulation thickness, copper oxidation, and electrode impedance over temporal intervals. Comparative analyses indicate that the short-term stability of the copper electrode is comparable to that of the gold electrode. Therefore, we propose a cost-effective strategy for fabricating copper-based on-skin bioelectrodes by introducing enhanced ionic stability within a discernible operational timeframe. This study enriches our understanding of on-skin bioelectronics and affordable material choices for practical use in wearable healthcare devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1996.11a
• /
• pp.417-420
• /
• 1996

We have investigated air/200ppm NO$_2$ gas-detector characteristics of using CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices. The CuTBP films were made by Langmuir-Blodgett (LB) techniques. Sensitivity, response time, recovery time, and repoducibility of the devices were measured by current-voltage characteristics. To increase sensitivity, interdigital electrode was used. It was found that a conductance G increases monotonically as the number of interdigital electrode increases, and a Sensitivity, Reproducibility is stable. As far as a current is concerned, the current when N=25 is greater than that when N=1 by 70 or so. It indicates that the number of interdigital electrodes affects the current, sensitivity and stability We have also investigated applicability of the CuTBP chemiresistor device for a gas detector.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.43-46
• /
• 2003

To develop bevel gear dies that have characteristics of high precision and enough life time, the technology of die manufacturing and design which increase the resistance of wear and fatigue is essentially needed. Here in the study, we have investigated several materials for dies and electrode. And, the most economical and suitable electrode material has been selected through the characteristic analysis of electrode materials such as copper, graphite and chromium copper. With the help of CAD/CAM/CAE, the total manufacturing system of high precision electrode for bevel gear has been established.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.761-762
• /
• 2006

W-Cu alloy was very useful material for a heat sink, high electric contact and EDM electrode. Powder injection molding (PIM) is the optimum manufacturing technology to provide W-Cu components with low-cost and high-volume. We used various compositions of tungsten coated copper powders (W-Cu with 10 to 80 wt-% of copper) to manufacture W-Cu components by PIM. The optimum mixing, injection molding, debinding and sintering conditions to provide the high performance W-Cu components were investigated. The thermal and mechanical properties of W-Cu parts by PIM were measured. Finally, we can verify the high performance of W-Cu components by PIM with the tungsten coated copper.