• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.285-290
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• 2018

The steel has been used in modern industry, car maker and electric appliance. The steel have some problem, specially corrosion problem. To solve corrosion problem, Zn electrodeposit on steel have been adapted. Recently, The modern industry asks to increase corrosion resistance. Naturally, Increasing corrosion resistance increases the thickness of Zn electrodeposit. But increasing thickness of Zn electrodeposit has some problems. In making part, There are some crack. This crack cause to decrease corrosion resistance. To solve this problem, it is interested in Zn Based alloy electrodeposit such as Zn-Cr. Here, the influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. The results are explained by the cathode overvoltage curve of Cr and Zn. As the current density of the cathode increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase. As the temperature of the electrolyte increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase.

• Korean Journal of Materials Research
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• v.31 no.12
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• pp.704-709
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• 2021

In the flux used in the batch galvanizing process, the effect of the component ratio of NH₄Cl to ZnCl₂ on the microstructure, coating adhesion, and corrosion resistance of Zn-Mg-Al ternary alloy-coated steel is evaluated. Many defects such as cracks and bare spots are formed inside the Zn-Mg-Al coating layer during treatment with the flux composition generally used for Zn coating. Deterioration of the coating property is due to the formation of AlCl_x mixture generated by the reaction of Al element and chloride in the flux. The coatability of the Zn-Mg-Al alloy coating is improved by increasing the content of ZnCl₂ in the flux to reduce the amount of chlorine reacting with Al while maintaining the flux effect and the coating adhesion is improved as the component ratio of NH₄Cl to ZnCl₂ decreases. Zn-Mg-Al alloy-coated steel products treated with the optimized flux composition of NH₄Cl·3ZnCl₂ show superior corrosion resistance compared to Zn-coated steel products, even with a coating weight of 60 %.

• 연구논문집
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• s.29
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• pp.163-171
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• 1999

A new titanium alloy system. Ti-xFe-ySi (x,y=0-4 wt%). was designed and characterized with the point at low cost and high strength for casting applications. Fe improved room and elevated temperature mechanical properties owing to solid solution hardening and beta phase stabilization. Si yielded titanium silicides and Si addition over 1 wt% resulted in poor ductility due to coarse silicide chains at prior beta boundaries. The optimum composition was found to be Ti-4Fe-(0.5-1)Si in the viewpoint of tensile strength and ductility which are comparable to the Ti-6Al-4V. The metal-mould reaction was also examined for Ti-xFe and Ti-xSi binary alloy system. The thickness of surface reaction layer w as not affected significantly with Fe content, while it was decreased with Si content. In the Ti-4Si alloy, no reaction layer was found. The depth of surface hardening layer was about $200\mum$ regardless of the mould materials.

• Corrosion Science and Technology
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• v.10 no.6
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• pp.194-198
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• 2011

This is the first release of an interim report on the development of coating technology of Zn-Mg alloy layers on steel strip by EML-PVD (electromagnetic levitation - physical vapor deposition) process in an air-to-air type continuous PVD pilot plant. It intends to introduce a basic principle of the EML-PVD process together with the high speed PVD pilot plant built in Posco. Due to the agitation effect provided by the high frequency induction coil, simultaneous evaporation of Zn and Mg from a droplet could produce alloy coating layers with Mg content of 6% to 12% depending on the composition of the droplet inside the coil. For its superior corrosion resistance, Zn-Mg alloy coated steel would be a very promising material for automotive, electrical appliances, and construction applications.

• Journal of Magnetics
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• v.4 no.2
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• pp.55-59
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• 1999

In an attempt to find an effective production way of the$ Sm_2Fe_{17}N_{x-}type material, the Sm_2Fe_{17-}$type alloy with chemical composition of Sm 22.7 wt.%, Fe72.3 wt.% Nb 5.0wt.% was subjected to a HD (hydrogen decrepitation) treatment prior to a nitrogenation, and its effect on the formation of the nitride material was investigated. The nitrogenation behaviours of the alloy were investigated using a TPA(thermopiezic analysis), TMA, and DTA under nitrogen gas, and XRD. It has been found that the previous HD treatment significantly facilitated the formation of $Sm_2Fe_{17}N_{x-}$type nitride, and this was accounted for by the clean surface and the finer particle size of the powder caused by the HD treatment. It has also been found that the hydrogen atoms existing in the initial HD-treated alloy were removed almost completely during the nitrogenation. The heat output associated with the nitrogenation of the previously HD-treated alloy was found to be significantly smaller than that of the as-cast alloy.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.113-118
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• 1997

For the amorphous F $e_{78}$ $B_{13}$S $i_{9-x}$G $e_{x}$ alloy, thermal analysis and measurements of the magnetic properties were carried out. As the content of Ge increased, the crystallization temperature was decreased and the Curie temperature was increased, and the tendencies were almost linear. The core loss of the amorphous alloy for x=1.7, field annealed at optimized condition, was 0.057 W/kg(l.0T, 60Hz), which was about 30% lower than that of no Ge added amorphous alloy (basic composition). Such a low core loss characteristics was thought to be caused by the lower coercive force and good squareness of B-H loop of the alloy.y.y.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.451-455
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• 1995

The composition and thickness dependence and the ferromagnetic under- and overlayer effect on the magnetoresistance ratio and saturation field of the Co-Ag nano-granular films were investigated. The maximum magnetoresistance (23% at R.T.) in the as-deposited state was obtained in the $3000{\AA}$ $Co_{30} Ag_{70}$ bare alloy film. As the thickness of the alloy films decreased below $500{\AA}$, the MR ratio decreased because of the resistivity increase and the non-uniform film formation. We showed that the ferromagnetic over- and underlayer could reduce the saturation field of the nano-granular films via exchange coupling effect. The magnetoresistance and the saturation field of the $100{\AA}$ alloy film were 3.65 % and 2.85 kOe respectively and those of the under- and overlayered alloy films with $200{\AA}$ Fe were 3.3 % and 1.23 kOe respectively.

• Journal of Powder Materials
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• v.22 no.5
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• pp.362-366
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• 2015

The effect of sublimable vehicle composition in the camphor-naphthalene system on the pore structure of porous Cu-Ni alloy is investigated. The CuO-NiO mixed slurries with hypoeutectic, eutectic and hypereutectic compositions are frozen into a mold at $-25^{\circ}C$. Pores are generated by sublimation of the vehicles at room temperature. After hydrogen reduction at $300^{\circ}C$ and sintering at $850^{\circ}C$ for 1 h, the green body of CuO-NiO is completely converted to porous Cu-Ni alloy with various pore structures. The sintered samples show large pores which are aligned parallel to the sublimable vehicle growth direction. The pore size and porosity decrease with increase in powder content due to the degree of powder rearrangement in slurry. In the hypoeutectic composition slurry, small pores with dendritic morphology are observed in the sintered Cu-Ni, whereas the specimen of hypereutectic composition shows pore structure of plate shape. The change of pore structure is explained by growth behavior of primary camphor and naphthalene crystals during solidification of camphor-naphthalene alloys.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.846-850
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• 2004

NiCo silicide films have been fabricated from $300{\AA}-thick\;Ni_{1-x}Co_{x}(x=0.1\sim0.9)$ on Si-substrates by varying RTA(rapid thermal annealing) temperatures from $700^{\circ}C\;to\;1100^{\circ}C$ for 40 sec. Sheet resistance, cross-sectional microstructure, and chemical composition evolution were measured by a four point probe, a transmission electron microscope(TEM), and an Auger depth profilemeter, respectively. For silicides of the all composition and temperatures except for $80\%$ of the Ni composition, we observed small sheet resistance of sub- $7\;{\Omega}/sq.,$ which was stable even at $1100^{\circ}C$. We report that our newly proposed NiCo silicides may obtain sub 50 nm-thick films by tunning the nickel composition and silicidation temperature. New NiCo silicides from NiCo-alloys may be more appropriate for sub-0.1${\mu}m$ CMOS process, compared to conventional single phase or stacked composit silicides.

• Transactions of the Korean hydrogen and new energy society
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• v.10 no.3
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• pp.185-189
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• 1999

Effects of alloy modification with the $Zr_{0.6}Ti_{0.4}V_{0.4}Ni_{1.2}Mn_{0.4}$ alloy for an electrode use have been investigated. For the alloy composition, a part of Mn was substituted by Co, Cr and Fe. The experimental results showed that Co accelerated activation of alloy, and Fe and Cr improved the discharge capacity. These results agree with P-C-T curves of each alloy. But substituting Fe for Mn showed the decrease of the discharge capacity when discharged at high rate (60mA, about 1C rate). Considering both the discharge capacity and the high rate discharge property, $Zr_{0.6}Ti_{0.4}V_{0.4}Ni_{1.2}Mn_{0.3}Cr_{0.1}$ alloy was found to be the best alloy among the alloys subjected to the test.