• 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.

• Journal of the Korean institute of surface engineering
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• v.8 no.1
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• pp.1-9
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• 1975

The crorosion film of gilt bronz, silver and iron objects, which were excaved from Ancient Tomb of Silla Dynasty, was removed by the electrolytic reduction process. These metallic objects were mainly investigated for microstructure, designs and gilting film etc. Most iron objects might be made by hot forging process. The cold extrusion technique might be used for gold and silver objects, in addition to an amalgam method might be applied for the gilting Au film on Cu-alloy surface. For the gilting on glass surface, first, a Cu alloy was cladded on glass , next, Au-film was obtained on the Cu-ally by the amagum method.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.55-65
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• 1998

The oxidation behavior of Ag-36.8a%Cu-7.4at%Ti alloy brazed on Si3N4 substrate was investigated at 400, 500 and 600$^{\circ}C$ in air. Under this experimental condition Si3N4 and Ag were not oxidized whereas Cu and Ti among the brazing alloy components were oxidizied obeying the parabolic oxidation rate law. The activation energy of oxidation was found to be 80kj/ mol which was smaller than that of pure Cu owing to the presence of oxygen active element of Ti. The outer oxide scale formed from the initial oxidation state was always composed of Cu oxides which were known to be growing by the outward diffusion of Cu ions. As the oxidation progressed the concentration gradient occurred due to the continuous consumption of Cu as Cu oxides and consequently build-up of an Ag-enriched layer below the Cu oxides resulted in the formation of multiple oxide scales composed of Cu oxide (CuO) /Ag-enriched layer/Cu oxide (Cu2O) /Ag-enriched layer. Also the inward diffusing of oxygen through Cu oxide and Ag-enriched layers led to the formation of internal oxides of TiO2.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.9-14
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• 2009

This study evaluated the mechanical properties of Ti-Cu alloys with the hope of developing an alloy for dental casting with better mechanical properties than unalloyed titanium. Ti-Cu alloys with four concentrations of Cu(2,5,10wt%) were made in an argon-arc melting furnace. The microstructure and micro-Vickers hardness were determined. X-ray diffraction pattern test was performed on the polished specimens. The microstructure of 2%Cu and 5%Cu alloys are shown acicular ${\alpha}Ti$ phase formed on the surfaces of previously formed $\beta$grains. The 10%Cu alloys has essentially a eutectoid structure; this structure includes lamella of ${\alpha}Ti$ and $Ti_2Cu$ phase that transformed from ${\alpha}Ti$ at the eutectoid temperature. The micro-Vickers hardness of CP Ti specimens was significantly(p<0.05) lower than that of any of the other alloys. Among the Ti-Cu alloys, the 10%Cu alloys exhibited a significantly(p<0.05) higher hardness value. but lower than that of Ti-6%Al-4%V alloy. From these results, it was concluded that new alloys for dental castings should be designed as Ti-Cu based alloys if other properties necessary for dental castings were obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.370-370
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• 2012

Feature size of Cu interconnects keep shrinking into several tens of nanometer level. For this reason, the Cu interconnects face challenging issues such as increase of electro-migration, line-width dependent electrical resistivity increase, and gap-filling difficulty in high aspect ratio structures. As the thickness of the Cu film decreases below 30 nm, the electrical resistivity is not any more constant, but rather exponential. Research on alloying with other elements have been started to inhibit such escalation in the electrical resistivity. A faint trace of Al added in Cu film by sputtering was reported to contribute to suppression of the increase of the electrical resistivity. From an industrial point of view, we introduced cyclic metal organic chemical vapor deposition (MOCVD) in order to control Al concentration in the Cu film more easily by controlling the delivery time ratio of Cu and Al precursors. The amount of alloying element could be lowered at level of below 1 at%. Process of the alloy formation was applied into gap-filling to evaluate the performance of the gap-filling. Voidless gap-filling even into high aspect ratio trenches was achieved. In-depth analysis will be discussed in detail.

• Korean Journal of Metals and Materials
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• v.47 no.11
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• pp.687-693
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• 2009

Experiments have demonstrated that a moderate amount of Be added to $Zr_{57.5}Cu_{38.3}Al_{4.2}$ amorphous alloy enhances the plasticity of the alloy. In particular, $Zr_{54}Cu_{36}Al_{4}Be_{6}$ alloy exhibited 19% of strain to fracture along with a strength exceeding 2 GPa. Energy dispersive x-ray spectroscopy conducted on the $Zr_{54}Cu_{36}Al_{4}Be_{6}$ alloy exhibited the presence of compositional modulation, indicating that nm-scale phase separation had occurred at local regions. In this study, the role played by the nm-scale phase separation on the plasticity was investigated in terms of structural disordering, structural softening and shear localization in order to better understand the structural origin of the enhanced plasticity shown by the developed alloy.

• Journal of Conservation Science
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• v.35 no.4
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• pp.309-316
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• 2019

This study intends to identify manufacturing techniques, including casting and alloy composition, of nine metal Buddha statues excavated from archaeological sites in Bagan, Myanmar. Two Buddha statues from Pyu city state(2^nd to 9^th century) contain Cu-Sn alloy(including <1 wt% Fe), with different relatively high percentages of Sn(16 wt% and 25 wt%) identified from each Buddha statue, and no Pb detected. Five Buddha statues from the Bagan dynasty contain various alloy ratios of Cu-Sn(including <1 wt% Pb), Cu-Sn-Pb, and Cu-Sn-Zn-Pb. All Buddha statues appear to be fabricated by casting, as there is no evidence of other heat treatments. The silver Buddha statue manufactured in the 18^th century includes >1% Cu besides silver with no additional metallic components identified. The bronze Buddha statue manufactured in the Konbaung dynasty(18^th century) is of Cu-Sn-Pb alloy. The Buddha statues of Pyu was alloy of Cu-Sn without Pb including ahigh percentage of The Buddha statues of both the Bagan and Konbaung dynasties are comprised of ternary Cu-Sn-Pb alloys, with a heterogeneous distribution of lead and tin. Some of Buddha statues of the Bagan dynasty have similar alloy ratios as those of Pyu, suggesting that similar manufacturing techniques were used.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.160-165
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• 2000

We have investigated the electrical and diffusion barrier properties of MgO produced on the surface of Cu (Mg) alloy. Also the diffusion barrier property of the interfacial MgO between Cu alloy and $SiO_2$ has been examined. The results show that the $150\;{\AA}$-MgO layer on the surface remains stable up to $700^{\circ}C$, preventing the interdiffusion of C Cu and Si in Si/MgO/Cu(Mg) structure. It also has the breakdown voltage of 4.5V and leakage current density of $10^{-7}A/\textrm{cm}^2/$. In addition, the combined structure of $Si_3N4(100{\AA})/MgO(100{\AA})$ increases the breakdown voltage up to lOV and reduces the leakage current density to $8{\tiems}10^{-7}A/\textrm{cm}^2$. Furthermore, the interfacial MgO formed by the chemical reac­t tion of Mg and $SiO_2$ reduces the diffusion of copper into $SiO_2$ substrate. Consequently, Cu(Mg) alloy can be applied as a g gate electrode in TFT /LCDs, reducing the process steps.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.413-416
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• 2009

The paper deals with the mechanical and electrical responses of submicrocrystalline Cu-3%Ag alloy as a function of strain imposed by equal-channel angular pressing. When inducing the effective strain of 12, the initial grain site of ${\sim}50{\mu}m$ is evidently reduced within the range of $0.2-0.3{\mu}m$ in size, having a reasonably equiaxed shape. The results of tension tests at room temperature exhibit that the tensile strength of the present alloy increases with increasing the amount of strain whereas losing electrical conductivity slightly. This phenomenon can be explained based on fine grained structure together with the non-equilibrium state of grain boundaries.

• Korean Journal of Materials Research
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• v.16 no.4
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• pp.257-263
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• 2006

We have investigated the effect of silver added to Cu films on the microstructure evolution, resistivity, surface morphology, stress relaxation temperature, and adhesion properties of Cu(Ag) alloy thin films deposited on Mo glue layer upon annealing. In addition, pure Cu films deposited on Mo has been annealed and compared. The results show that the silver in Cu(Ag) thin films control the grain growth through the coarsening of its precipitates upon annealing at $300^{\circ}C{\sim}600^{\circ}C$ and the grain growth of Cu reveals the activation energy of 0.22 eV, approximately one third of activation energy for diffusion of Ag dopant along the grain boundaries in Cu matrix (0.75 eV). This indicates that the grain growth can be controlled by Ag diffusion along the grain boundaries. In addition, the grain growth can be a major contributor to the decreased resistivity of Cu(Ag) alloy thin films at the temperature of $300^{\circ}C{\sim}500^{\circ}C$, and decreases the resistivity of Cu(Ag) thin films to $1.96{\mu}{\Omega}-cm$ after annealing at $600^{\circ}C$. Furthermore, the addition of Ag increases the stress relaxation temperature of Cu(Ag) thin films, and thus leading to the enhanced resistance to the void formation, which starts at $300^{\circ}C$ in the pure Cu thin films. Moreover, Cu(Ag) thin films shows the increased adhesion properties, possibly resulting from the Ag segregating to the interface. Consequently, the Cu(Ag) thin films can be used as a metallization of advanced TFT-LCDs.