• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.67-71
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• 2021

In this study, graphene layer was grown on metal microwire using chemical vapor deposition. The difference of carbon solubility between copper and nickel resulted in the formation of mono-layer and multi-layer graphene were formed on the surfaces of copper and nickel microwires, respectively. During the growth of graphene at high temperature, copper and nickel were recrytallized and the grain size increased. The ampacity of graphene/copper microwire was improved by approximately 27%, 1.91×105 A/㎠, compared to pristine copper microwire. Similar to this behavior, the ampacity of multilayer graphene/nickel microwire was 4.41×104 A/㎠ which is about about 36% improved compared to the pure nickel microwire. The excellent electrical properties of graphene/metal composites are beneficial for supplying the electrical energy to the high-power electronic devices and equipment.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.1-8
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• 1997

Varing the flow velocity of solution and particle diameter, the mass transfer coefficient of the local electrode on current feeder has been measured in an empty flow reactor, an inert fluidized bed electrode reactor, and an active fluidized bed electrode reactor. It had its maximium value when the bed porosity was 0.6 to 0.65 and decreased with in- creasing the height of local electrode. The mass transfer coefficient was found to be high especially when higher particle was fluidized. Electrochemical deposition of copper dissolved in the synthesized wastewater has been performed in the active fluidized bed electrode reactor. The deduction rate was higher than 90% and the residual concentration of copper decreased to less than 5ppm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.58-63
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• 2019

Lithium-ion batteries used for IT, automobiles, and industrial energy-storage devices have battery management systems (BMS) to protect the battery from abnormal voltage, current, and temperature environments, as well as safety devices like, current interruption device (CID), fuse, and vent to obtain positive temperature coefficient (PTC). Nonetheless, there are harmful to human health and property and damage the brand image of the manufacturer because of smoke, fire, and explosion of lithium battery packs. In this paper, we propose a systematic protection algorithm combining battery temperature, over-current, and interconnection between protection elements to prevent copper deposition, internal short circuit, and separator shrinkage due to frequent and instantaneous over-current discharges. The parameters of the proposed algorithm are suggested to utilize the experimental data in consideration of battery pack operating conditions and malicious conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.873-880
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• 2018

Objective: The objective of this experiment was to compare the effects of adding 130 mg/kg Cu from either copper sulfate (CS) or tribasic copper chloride (TBCC) on growth performance, mineral deposition in tissues, and the excretion in feces of pigs as well as changes in the mineral contents in tissues and feces when the supplemental Cu level was decreased from 130 mg/kg to 10 mg/kg. Methods: A total of 72 pigs ($32.6{\pm}1.2kg$) were randomly assigned to a CS diet or a TBCC diet with 6 pens per treatment. The trial lasted 102 d and included 3 phases (phase 1, 1 to 30 d; phase 2, 31 to 81 d; and phase 3, 82 to 102 d). The supplemental levels of Cu in the 2 treatments were 130 mg/kg in phase 1 and 2 and 10 mg/kg in phase 3. Results: The results showed that pigs fed the CS diet tended to have higher average daily gain than pigs fed the TBCC diet during d 1 to 81 (p<0.10). Compared with CS, TBCC increased the activities of aspartate transaminase (AST), ceruloplasmin, and superoxide dismutase in serum on d 30 (p<0.05). The TBCC decreased the Cu level in the liver on d 81 (p<0.05) and increased the Mn level in the liver on d 102 (p<0.05). The concentration of Cu in feces sharply decreased when the supplemental Cu level in diet changed from 130 mg/kg to 10 mg/kg in both diets (p<0.05). Conclusion: The result suggested that TBCC and CS had no significant difference on growth performance but TBCC had higher activities of AST and antioxidant enzymes and lower liver Cu than CS when pigs fed diets with 130 mg Cu /kg diet.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.183-195
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• 2014

In order to study the mineralogical characteristics of a cathodic deposition-metallic powder, electrowinning experiments were carrier out on different electrolytic solutions at varying electric distances and electric currents. Under the same experimental conditions, Cu recovery was obtained much more effectively using a sodium chloride electrolyte than with a sulfuric acid electrolyte. In XRD analysis, copper ($Cu^0$), chalcanthite and cuprite were identified in the sulfuric acid electrolyte, while copper, nantokite and chalcanthite were observed in the sodium chloride electrolyte. In the sodium chloride electrolyte solution, increasing the electric distance and the electric current increased the Cu recovery rate, anode weight and anodic corrosion. The results of XRD analysis with non-pulverized cathodic deposition-metallic powder showed the average copper crystallite size was increased by increasing the electric current and decreasing the electric distance. It is suggested that the mass transfer was controlled with diffusion on the boundary between the electrode and the electrolytic solution due to the formation of dendrite copper.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1196-1204
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• 1999

We have carried out copper MOCVD(metalorganic chemical vapor deposition) onto the reactive sputtered PVD-TiN and rapid thermal converted RTP-TiN substrates using direct liquid injection for effective delivery of the (hfac)Cu(vtmos) [$C_{10}H_{13}O_{5}CuF_{6}$Si: 1,1,1,5,5,5-hexafluoro-2,4- pentadionato (vinyltrimethoxysilane) copper (I)] precursor. Especially, the influences of deposition conditions and the substrate type on growth rate, crystal structure, microstructure, and electrical resistivity of copper deposits have been discussed. It is found that the film growth with 0.2ccm precursor flow rate become mass-transfer controlled up to Ar flow rate of 200sccm and pick-up rate controlled at a vaporizer above 1.0Torr reactor pressure. The surface-reaction controlled region from 155 to 225$^{\circ}C$ at 0.6Torr reactor pressure results in the apparent activation energies of 12.7~14.1kcal/mol, and above 224$^{\circ}C$ the growth rate with $H_2$ addition could be improved compared to the pure Ar carrier. The Cu/RTP-TiN structures which have high copper nucleation density in initial stage of growth show more pronounced (111) preferred orientations and lower electrical resistivities than those on PVD-TiN. The variation of electrical resistivity with substrate temperature reflects the three types of film microstructure changes, showing the lowest value for the deposit at 165$^{\circ}C$ with small grains of good contacts.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.122-127
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• 2017

Graphene grown on copper-foil substrates by chemical vapor deposition (CVD) has been attracting interest for sensor applications due to an extraordinary high surface-to-volume ratio and capability of large-scale device fabrication. However, CVD graphene has a polycrystalline structure and a high density of grain boundaries degrading its electrical properties. Recently, processes such as electropolishing for flattening copper substrate has been applied before growth in order to increase the grain size of graphene. In this study, we systemically analyzed the effects of the process condition of electropolishing copper foil on the quality of CVD graphene. We observed that electropolishing process can reduce surface roughness of copper foil, increase the grain size of CVD graphene, and minimize the density of double-layered graphene regions. However, excessive process time can rather increase the copper foil surface roughness and degrade the quality of CVD graphene layers. This work shows that an optimized electropolishing process on copper substrates is critical to obtain high-quality and uniformity CVD graphene which is essential for practical sensor applications.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.134-134
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• 2016

The effect of different thermal treatments on the sub-50 nm copper nanoparticles is examined in the aspects of chemical, electrical and surface morphology. The copper nanoparticles are chemically synthesized and fabricated for paste-type solution. Simple bar coating method is practiced as a deposition process to form copper thin film on a typical slide glass. Deposited copper thin films are annealed by two different routes: general tube furnace with 99.99 % Ar atmosphere and selective laser sintering process. The thermal behavior of the different thermal-treated copper thin films is compared by SEM, XRD, FT-IR and XPS analysis. In this study, the laser sintering process ensures low annealing temperature, fast working speed and ambient-accessible route. Moreover, the laser-sintered copper thin film shows good electrical property and enhanced chemical stability than conventional thermal annealing process. Consequently, the proposed laser sintering process can be compatible with plastic substrate for flexible applications.

• Korean Journal of Materials Research
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• v.18 no.3
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• pp.163-168
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• 2008

The morphology of three-dimensional (3D) cross-linked electrodeposits of copper and tin was investigated as a function of the content of metal sulfate and acetic acid in a deposition bath. The composition of copper sulfate had little effect on the overall copper network structure, whereas that of tin sulfate produced significant differences in the tin network structure. The effect of the metal sulfate content on the copper and tin network is discussed in terms of whether or not hydrogen evolution occurs on electrodeposits. In addition, the hydrophobic additive, i.e., acetic acid, which suppresses the coalescence of evolved hydrogen bubbles and thereby makes the pore size controllable, proved to be detrimental to the formation of a well-defined network structure. This led to a non-uniform or discontinuous copper network. This implies that acetic acid critically retards the electrodeposition of copper.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.1
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• pp.34-46
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• 2004

Copper films were prepared by using ECR-MOCVD(Electron Cyclotron Resonance Metal Organic Chemical Vapor Deposition) coupled with a DC bias system. The DC bias is connected to the electrode which placed 1∼3cm above the polymer substrate. The pulse electrical field around the electrode attracts the positive charged copper ions generated from the dissociation of copper precursor, $Cu(hfac)_2$, under ECR plasma. Condensation of supersaturated copper ions in the space between the electrode and substrate, makes it possible to deposit copper film on the polymer substrate even at room temperature. In this study, optimization of the electrode configuration was carried out in order to obtain the uniform films. The uniformity of the deposited films were closely related to the parameters of electrode geometry such as electrode shape, thickness, grid size and the spacing between electrodes. The most uniform copper film was observed with the electrode that enabled uniform electrical field distribution across the whole dimension of electrode.