• Journal of Powder Materials
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• v.11 no.5
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• pp.376-382
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• 2004

Nanoscale Cu-Ni alloy nanopowders have been produced by a pulsed wire evaporation method in an inert gas. The effect of Cu-Ni alloy nanopowders as additives to motor oil on the tribological properties was studied at room temperature. The worn surfaces were characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). Cu-Ni alloy nanopowders as additives lowered coefficient of friction and wear rate. It was found that a copper containing layer on the worn surface was formed, and deposited layers of the metal cladding acted as lubricant on the worn surface, reducing the friction coefficient. It was clearly demonstrated that Cu-Ni alloy nanopowders as additives are able to restore the worn surface and to preserve the friction surfaces from wear.

• Journal of Powder Materials
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• v.13 no.3 s.56
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• pp.187-191
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• 2006

Al-Cu alloy nano powders were produced by the electrical explosion of Cu-plated Al wires. The composition and phase of the alloy could be controlled by varying the thickness of Cu deposit on Al wire. When the Cu layer was thin, Al solid solution and $CuAl_2$ were the major phases. As the Cu layer becomes thicker, Al diminished while $Al_4Cu_9$ phase prevailed instead. The average particle size of Al-Cu nano powders became slightly smaller from 63 nm to 44 nm as Cu layer becomes thicker. The oxygen content of Al-Cu powder decreased linearly with Cu content. It is well demonstrated that the electrodeposition combined with wire explosion could be simple and economical means to prepare variety of alloy and intermetallic nano powders.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.66-66
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• 2009

Various alloy system, such as Cu-Sn-Ti, Cu-Ag-Ti, and Ni-B-Cr-based alloy are used for the brazing of diamond grits. However, the problem of the adhesion strength between the diamond grits and the brazed alloy is presented. The adhesion strength between the diamond grits and the melting filler alloy is predicted by the contact angle, thereby, instead of diamond grit, the study on the wettability between the graphite and the brazing alloy has been indirectly executed. In this study, Cu-13Sn-12Ti filler alloy was manufactured, and the contact angles, the shear strengths and the interfacial area between the graphites(diamond grits) and braze matrix were investigated. The contact angle was decreased on increasing holding time and temperature. The results of shear strength of the graphite joints brazed filler alloys were observed that the joints applied Cu-13Sn-12Ti alloy at brazing temperature 940 $^{\circ}C$ was very sound condition indicating the shear tensile value of 23.8 MPa because of existing the widest carbide(TiC) reaction layers. The micrograph of wettability of the diamond grit brazed filler alloys were observed that the brazement applied Cu-13Sn-12Ti alloy at brazing temperature $990^{\circ}C$ was very sound condition because of existing a few TiC grains in the vicinity of the TiC layers.

• Journal of Welding and Joining
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• v.28 no.3
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• pp.49-58
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• 2010

Various alloy system, such as Cu-Sn-Ti, Cu-Ag-Ti, and Ni-B-Cr-based alloy are used for the brazing of diamond grits. However, the problem of the adhesion strength between the diamond grits and the brazed alloy is presented. The adhesion strength between the diamond grits and the melting filler alloy is predicted by the contact angle, thereby, instead of diamond grit, the study on the wettability between the graphite and the brazing alloy has been indirectly executed. In this study, Cu-13Sn-12Ti filler alloy was manufactured, and the contact angles, the shear strengths and the interfacial area between the graphites (diamond grits) and braze matrix were investigated. The contact angle was decreased on increasing holding time and temperature. The results of shear strength of the graphite joints brazed filler alloys were observed that the joints applied Cu-13Sn-12Ti alloy at brazing temperature $940^{\circ}C$ was very sound condition indicating the shear tensile value of 23.8 MPa because of existing the widest carbide(TiC) reaction layers. The micrograph of wettability of the diamond grit brazed filler alloys were observed that the brazement applied Cu-13Sn-12Ti alloy at brazing temperature $990^{\circ}C$ was very sound condition because of existing a few TiC grains in the vicinity of the TiC layers.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.948-949
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• 2006

An infiltration technique using W-Cu composite powder has been developed to enhance microstructural uniformity of W-Cu pseudo-alloy. W-Cu composite powder, manufactured by reduction from $WO_3$ and CuO powder mixtures, were blended with W powder and then cold iso-statically pressed into a cylindrical bar under 150 MPa. The pressed samples were pre-sintered at $1300^{\circ}C$ for 1 hour under hydrogen to make a skeleton structure. This skeleton structure was more homogeneous than that formed by using W and Cu powder mixtures. The skeleton structures were infiltrated with Cu under hydrogen atmosphere. The infiltrated W-Cu pseudo-alloy showed homogeneous microstructure without Cu rich region

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.331-339
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• 2004

Melt-extrusion process, a metallic melt poured and solidified up to semisolid state in the container can be directly extruded through the die exit to form a product of bar shape without other intermediate processes. In this study, the fabrication characteristics of the process were evaluated with various process parameters, such as preheating temperature of extrusion dies, extrusion temperature and extrusion ratio. AI-Cu alloys were successfully extruded after squeezing out of liquid during melt-extrusion with smaller force compared to the solid extrusion. Soundly AI-Cu alloy bar was fabricated at the preheating temperature of $500{\sim}520^{\circ}C$. The range of extrusion temperature for soundly melt-extruded AI-Cu alloy bar was increased with increasing extrusion ratio. Mechanical properties of melt-extruded AI-Cu alloy bars were found change with Cu content of the melt-extruded bars due to the occurrence of segregation. The various extrusion temperature yielded equiaxed structure with a grains size about 200 ${\mu}m$.

• 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.

• Journal of Korea Foundry Society
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• v.41 no.1
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• pp.3-10
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• 2021

In the compound casting between the aluminum alloy and the cast iron, the iron component may be dissolved from the cast iron during the process and mixed into the aluminum melt, thereby forming various iron-containing intermetallic compounds and significantly deteriorating the tensile properties of the aluminum alloy. On the other hand, unlike Fe, which is added as an impurity, Cu is added to improve the mechanical properties of the aluminum alloy. In this study, the change in microstructure and tensile properties of aluminum alloys due to the addition of Fe and Cu was investigated. A large amount of iron-containing compounds such as coarse Al₅FeSi phases were formed when the iron content was 1% or more, and the tensile properties were significantly reduced. In the case of the aluminum alloy to which Cu was added, an Al₂Cu phase was additionally formed and the tensile strength was clearly improved.

• Journal of the Korean institute of surface engineering
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• v.46 no.5
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• pp.208-215
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• 2013

The aim of the present study was to improve the radiative heat dissipation of aluminum alloy, Al 1050. Resin/CuO coating and Cu/CuO composite plating were applied on aluminum alloy to improve the radiative heat dissipation. Resin/CuO coating was made using thermosetting silicon resin and Cu/CuO composite plating was made in pyrophosphate copper plating bath. Radiant heat flux($W/m^2$) was measured by self-produced radiant heat measurement device to compare each specimen. The cross section of specimen and chemical bonding of surface were analyzed by FE-SEM, XPS and FT-IR. As a result, radiant heat of Resin/CuO coating was higher than Cu/CuO composite plating due to the adhesion with aluminum plate and the difference in chemical bonding. But, Both of them were higher than aluminum alloy. In order to confirm the result of experiment, aluminum plate, Resin/CuO coating and Cu/CuO composite plating sample were applied LED and measured the LED temperature. As a result, LED temperature of samples were matched previous results and confirmed coated samples were lower about 10 degrees than the aluminum alloy.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.291-297
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• 2007

The field emission properties of CNT-emitters coated with Ag-Cu alloy have been investigated. The vertical aligned multi-walled CNTs were synthesized by dc-plasma enhanced chemical vapor deposition (dc-PECVD) and the Ag-Cu alloy was coated by using dc-magnetron sputter. The morphology of alloy-coated and un-coated CNT-emitters was observed by using SEM and their field emission properties were also measured. Annealing the AgCu-coated CNTs at temperature more than ${\sim}700^{\circ}C$, the Ag-Cu alloy was diffused to and aggregated on the top of the CNT as a Q-tip. A significant progress on the field emission was not observed with coating Ag-Cu alloy on the CNTs, but a certain improvement in a resistance against oxygen gas was made confirmation. It seems to be due to inertness of Ag-Cu alloy on the CNTs.