• Korean Journal of Materials Research
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• v.7 no.8
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• pp.701-706
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• 1997

AI-2.5wt%Li 합금을 시효처리하여 시효거동과 인장성질에 미치는 $\delta$' 상의 영향을 조사하였다. $\delta$' 상의 입자 반경은 시효 시간의 1/3승에 비례하여 조대화하였다. $\delta$' 상과 기지상과의 계면에너지는 0.0073 J/$m^2$, 확산계수는 1.42$\textrm{cm}^2$/sec, 초대화 거동은 MLSW이론에 부합됨을 알 수 있었다. 미세하고 균일하게 분포한 $\delta$'상은 전반적으로 인장강도의 상승을 가져왔으며, 평형상인 $\delta$상의 석출과 이로 인한 무석출물대의 존재로 과시효시 강도가 감소하였다. 인장변형시 전위는 초전위로 아시효와 피크시효시에는 $\delta$'상을 전단하지만 과시효시에는 $\delta$'상을 전단하지 못하고 우회하여 전위루우프를 형성한다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.157-160
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• 1999

Aluminum 4343(filler thickness ; 10${\mu}{\textrm}{m}$/Al 3N03(core 80${\mu}{\textrm}{m}$)/Al 4343(filler 10${\mu}{\textrm}{m}$) clad sheet which is recently developed as brazing sheet materials for automotive condensers was fabricated by castinglongrightarrowhot rollinglongrightarrowcold rollinglongrightarrowintermediate annealing(IA)longrightarrowfinal cold rolling(CR). and the effect of IA/CR conditions on microstructure and sagging resistance were investigated the sheet which were fabricated by optimum conditions (IA'ed at 42$0^{\circ}C$ followed by CR'ed to 20~45%) showed good sagging resistance because the core obtained a coarsely recrystallized grain structure during brazing and consequently inhibited filled alloy penetration into the core.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.40-42
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• 1999

In this paper, light-weight system of linear induction motor(LIM) for light railway train is presented, and is compared with former type of LIM. For the light-weight system without modification of motor size the material of primary core(silicon steel) is changed with iron-cobalt alloy and the material of primary winding(copper) is changed with aluminium. The characteristics of LIM are analyzed. Specially, the air gap magnetic flux density distribution due to end effect is showed with motor velocity, we will present papers continuously through designing and testing a trial product.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.123.2-123.2
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• 2017

Fe-Ni-Cu 합금 전주를 위하여 황화물 용액에의 상의 열역학적 안정도를 작성하고 전주 조건을 선정하였다. $Fe-Ni-Cu-S-H_2O$ 용액의 열역학적 상의 안정도를 전산모사하기 위한 프로그램은 C#으로 작성하였다. JANAF 자료를 근거한 적정 전주 조건은 $130mA/cm^2$, $50{\sim}55^{\circ}C$, pH 2.4 이었다. XRF을 이용한 Fe-Ni-Cu의 합금 도막의 평균 조성은 Fe-42Ni-1Cu [wt.%] 이었다, 전류밀도가 낮아질수록 Ni과 Cu량은 증가하였다. 구리 농도가 증가하면 표면조도는 60 nm로 변화하였다.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.78-83
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• 1999

Solder joint is the weakest part which connects in mechanically and electronically between package body and PCB(Printed Circuit Board). Recently, the reliability of solder joint become the most critical issue in surface mounted technology. The solder joint interconnection between plastic package and PCB is susceptible to shear stress during thermal storage due to the mismatch in coefficient of thermal expansion between plastic package and PCB. A general computational approach to determine the effect of solder joint shape on the fatigue life presented. The thermal fatigue life was estimated from the engelmaier equation which was obtained from the temperature cycling loading($-65^{\circ}C$ to $150^{\circ}C$). As result of the simulation, TSOP structure has the shortest thermal fatigue life and the same structure Copper lead has 2.5 times as much fatigue life as Alloy 42 lead. In BGA structure, fatigue life time extended 80 times when underfill material exists.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.129-133
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• 2005

대기압 글로우 플라즈마를 이용하여 반도체 리드프레임(Alloy 42) 도금 전처리 습식 공정을 건식으로 대체하였다. 13.56 MHz의 RF 전원을 사용하여 300 W 파워에서 안정적인 대기압 글로우 플라즈마를 발생시켰으며, 금속 리드프레임에 플라즈마가 직접 접촉해도 아크나 스트리머 발생이 없었다. 플라즈마 소스 가스로는 알곤(Ar)을 사용하였으며, 활성가스로 산소($O_2$)를 첨가하였다. 300 W 파워에서 산소를 50 sccm 공급하고 100 mm/sec 속도로 리드프레임을 처리한 결과, 처리 전 접촉각이 $82^{\circ}$에서 처리 후 $10^{\circ}$ 이하로 낮아졌다. 플라즈마 처리 후 리드프레임 표면 거칠기 변화를 AFM으로 측정하였다.

• The Journal of the Korean dental association
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• v.11 no.5
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• pp.353-358
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• 1973

The purpose of this study was to determine the gingival response to the various restorations for 3 weeks, 5 weeks and 8 weeks respectively after they had been inserted in 42 tooth of 5dogs. The histopathological observation was also performed to evaluate the effect of the variuos restorations on gingival tissue. They inclued gold, copper and nickel-chrome alloy. The following findings were obtained. 1. The gingivae adjacent to the well adapted and polished restorations and their margins with a level of gingival crest were grossly and histopathologically found no specific changes. 2. The gingive adjacent to the ill fitting and unpolished restorations and their margins with subgingival extension of 1 to 1.5mm were not grossly found any changes but hitopathologically, the inflammatory changes. 3. Thee wee no obvious difference in gingival response among the various alloys in histopathological observation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.658-662
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• 2000

The microstructure, adhesion strength and conductivity of electroplated Sn-Cu Films on Alloy42 lead Frame were measured for comparison. In the case of electroplated 90Sn10Cu, 99Sn1Cu, Cu$\sub$10/Sn$_3$Phase was formed and Ni$_3$Sn$_2$Phase was formed after 200$^{\circ}C$, 30min annealing. In the case of electroplated 99Sn1Cu, Cu$\sub$10/Sn, Ni$_3$Sn phases were formed and Ni$_3$Sn$_4$, Ni$_3$Sn$_4$phases were formed after 200$^{\circ}C$, 30min annealing. 90Sn10Cu film was measured better uniformity, adhesion strength and conductivity than 99Sn1Cu.

• Journal of Welding and Joining
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• v.26 no.5
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• pp.36-42
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• 2008

Carbon nanotube (CNT) aluminum composite coatings were built up through kinetic spraying process. Deposition behavior of CNT aluminum composite on an aluminum 1050 alloy substrate was analyzed based on deposition mechanism of kinetic spraying. The microstructure of CNT aluminum composite coating were observed and analyzed. Also, the electrical resistivity, bond strength and micro-hardness of the CNT aluminum composite coatings were measured and compared to kinetic sprayed aluminum coatings. The CNT aluminum composite coatings have a dense structure with low porosity. Compared to kinetic sprayed aluminum coating, the CNT aluminum composite coatings present lower electrical resistivity and higher micro-hardness due to high electrical conductivity and dispersion hardening effects of CNTs.

• Journal of the Korean institute of surface engineering
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• v.32 no.1
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• pp.31-42
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• 1999

The effect was investigated that aluminium in the zinc bath has on the coating adhesion of Hot-rolled Galvanized Iron(HGI) manufactured without pickling process. It is thought that the coating adhesion of HGI manufactured without pickling process is good due to the fact that increasing aluminium content in the zinc bath makes zinc and aluminium diffuse to the cracks or pores in the scale formed through the reduction heat treatment, and Fe-Zn-Al compound with good ductility is formed in the scale layer and plays a role of anchor between zinc coating and substrate. It is possible that HGI with the good coating adhesion was produced without pickling treatment in the zinc bath with more that 3wt% of Al content even at the $550^{\circ}C$ of conventional reduction heating temperature. In creasing the temperature of heating section and aluminium content in the zinc bath prevents the Zn-Fe alloy. The corrosion resistance of HGI manufactured without pickling process is excellent because of the mixed reaction of zinc sacrifice and aluminium passivity film.