• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.99-102
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• 2010

Large-scaled area and aligned copper oxide nanowires have been synthesized by a vapor-phase approach to the facial synthesis of copper oxide nanowires supported on the surface of a copper gasket. The effects of annealing temperature and time were investigated. Long and aligned nanowires can only formed within a narrow temperature range from 400 to $500^{\circ}C$ for 4 hrs. Annealing copper gasket in static air produces large-area, uniform, but not well vertically aligned nanowires along the copper gasket surface. The surface of copper gasket is converted into bicrystal CuO nanowires was observed after the copper gasket is annealed under static air condition.

• KSTLE International Journal
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• v.2 no.1
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• pp.22-28
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• 2001

A resin bonded copper-graphite brush was investigated to evaluate the characteristics electrical signal transmission through a sliding contact as a function of the relative amount of graphite and copper in the brush. Particular attention was given to the correlation between electrical signal fluctuation and tribological properties in an electrical sliding contact system. A ring-on-block type tribotester was used for this experiment and the ring was made from pure copper. Results showed that a copper-graphite brush at a particular composition range exhibited the most stable frictional behavior with a minimum voltage drop. The amount of voltage drop at the friction interface was affected by the surface roughness, transfer film formation at the friction interface, and the real area of contact. Microscopic observations and the surface analysis showed a good agreement with the results from this experiment. The results also indicated that the electrical signal flunctuation was directly associated with the oscillation of the coefficient of friction during sliding by nanoscale variation of contacts at the friction interface.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.151.1-151.1
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• 2017

This work studied the corrosion behavior of AZ31 Mg alloy galvanically coupled with Cu during immersion in 0.1 and 0.5 M NaCl solutions by in-situ observation and galvanic corrosion current measurement using a zero resistance ammeter. The corrosion behavior of AZ31 Mg alloy was also studied by salt spray test. The average galvanic corrosion density during 2 h immersion in 0.1 NaCl solution was found to decrease as an exponential function with increasing the surface area ratios between AZ31:Cu or with increasing the distance between AZ31 and Cu. The corrosion of electrodeposited Cu on AZ31 Mg alloy was concentrated at the area next to Cu (about 5 mm for immersion test and 2 mm for salt spray test) and pitting corrosion was accelerated at the area beyond the severely corroded area by the galvanic coupling effect.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.863-867
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• 2008

Pitch based activated carbon fiber(ACF) was prepared from reformed naphtha cracking bottom oil(NCB oil) by melt spinning. The fibers obtained were stabilized, carbonized, and then steam activated. The ACF was sensitized with Pd-Sn catalytic nuclei via a single-step activation approach. This sensitized ACF was used as precursors for obtaining copper plated ACFs via electroless plating. ACFs uniformly decorated with metal particles were obtained with reduced copper plating in the reaction solution. Effects of the amount of copper on characteristics of ACF/Cu catalysts were investigated through BET surface area, X-ray diffraction, scanning emission microscopy, and ICP. The amount of copper increased with plating time, but the surface area as well as the pore volume decreased. NO conversion increased with reaction temperature. NO conversion decreased with increasing the amount of copper, which is seemed to be due to the reduction of surface area as well as the dispersion of copper.

• Journal of the Korean Society of Safety
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• v.14 no.1
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• pp.86-92
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• 1999

This study was carried out to investigate the effect of chemical cleaning of corrosion product on cooling system made of copper as a basic material and using cooling water as pure water. We studied chemical cleaning condition that minimizes the influence on basic material by means of EDTA solution so as to eliminate the slurry in cooling system. In addition, the proper amount of NALCO-39L (Nitrite-Borate-BZT mixture) as a inhibitor was determined in order to protect the copper in cooling system against corrosion after chemical cleaning and the effect of corrosion resistance on the copper surface treated was excelent in comparison with surface untreated. As a result, we found that the main components of sludge in cooling system produced by corrosion of copper were $Cu_2O$, CuO, Cu, and Fe. The optimum condition of chemical cleaning was 400ppm EDTA solution at $60^{\circ}C$. Inhibitor concentration needed to treat the surface of pure copper was 15～20ppm per unit area and corrosion rate of copper treated with 500ppm inhibitor solution for 72 hrs at $60^{\circ}C$ was remarkably decreased as compared with that of pure copper.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.51-57
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• 2019

To protect the Cu surface from oxidation in air, a two-step plasma process using Ar and $N_2$ gases was studied to form a copper nitride passivation as an anti-oxidant layer. The Ar plasma removes contaminants on the Cu surface and it activates the surface to facilitate the reaction of copper and nitrogen atoms in the next $N_2$ plasma process. This study investigated the effect of Ar plasma on the formation of copper nitride passivation on Cu surface during the two-step plasma process through the full factorial design of experiment (DOE) method. According to XPS analysis, when using low RF power and pressure in the Ar plasma process, the peak area of copper oxides decreased while the peak area of copper nitrides increased. The main effect of copper nitride formation in Ar plasma process was RF power, and there was little interaction between plasma process parameters.

• Journal of the Korean institute of surface engineering
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• v.49 no.5
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• pp.416-422
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• 2016

We have investigated the effects of applied potential, deposition time and electrolyte types on shapes and physical properties of Cu dendrites by potentiostatic electrodeposition. Finer shape of dendrites was observed at less cathodic potential by 100mV than at the limiting current, due to 'effective overpotential'. The shape of copper dendrite is related to the deposition time, too. The dendrite depositing for 10 min showed the finest shape. The finer dendrite has the less apparent density and the larger specific surface area. Dendrite from chloride solution has the lowest density and the largest surface area among three plating solutions, sulfate, chloride and pyrophosphate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.616-621
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• 2010

New type of the base material of the light-emitting diode requires copper wafer in view of heat and electrical conductance. Therefore, polishing process of the substrate level is needed to get a nanometer level of surface roughness as compared with pattern structure of nano-size in the semiconductor industry. In this paper, a series of lapping and polishing technique is shown for the rough and deflected copper substrate of thickness 3mm. Lapping by sand papers tried air cooling method. And two steps of polishing used the diamond abrasives and the $Al_2O_3$ slurry of size 100mm considering the residual scratch. White-light interferometer proved successfully a mirror-like surface roughness of Ra 6nm on the area of $0.56mm{\times}0.42mm$.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.8
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• pp.334-340
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• 2006

Copper is widely used in electric wire, cable, conductor in electric devices. As the demand for electric power is increasing rapidly, electric power devices are getting amazingly bigger and complicated. The using of light-weight conductor can reduce the size and making cost of the electric devices. In high-frequency application, Electric current in a conductor tends to shift to the surface of the conductor, resulting in an uneven current distribution in the inner conductor. In the extreme case the current may essentially concentrate in the 'skin' of the inner conductor as a surface current. In high frequency application, therefore, inner area of copper conductor may replace with aluminum conductor, which reduces the weight of conductor. This paper describes the manufacture and evaluation of composite conductors made of copper and aluminum. The optimum extruding ratio was 16 at $300^{\circ}C$. The electrical resistance of manufactured composite bus bar was $57{\mu}{\Omega}$ at DC and $49.5{\mu}\{Omega}$ at 300Hz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.496-499
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• 2012

Modified structure of copper pillar bump which has trapezoidal cross section on the top region is suggested with simulation results and concept of fabrication process. Due to the large surface area of joint region between bump and solder in suggested structure, electro-migration effect can be reduced. Reduction of electro-migration is related with current density and joule heating in bump and investigated with finite element methods with variation of dimensional parameters. Mechanical characteristics are also investigated with comparing modified copper pillar bump and conventional copper pillar bump.