• Journal of the Korean Magnetics Society
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• v.20 no.2
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• pp.35-40
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• 2010

The GMR-SV (giant magnetoresistance-spin valve) device depending on the micro patterned features according to two easy directions of longitudinal and transversal axes has been studied. The GMR-SV multilayer structure was Ta(5 nm)/NiFe(8 nm)/Cu(2.3 nm)/NiFe(4 nm)/IrMn(8 nm)/Ta(2.5 nm). The applied anisotropy direction of the GMR-SV thin film was performed under the magnitude of 300 Oe using by permanent magnet during the deposition. The size of micro patterned device was a $1\;{\times}\;18\;{\mu}m^2$ after the photo lithography process. In the aspects of the shape magnetic anisotropy effect, there are two conditions of fabrication for GMR-SV device. Firstly, the direction of sensing current was perpendicular to the magnetic easy axis of the pinned NiFe/IrMn bilayer with the transversal direction of device. Secondly, the direction of shape magnetic anisotropy was same to the magnetic easy axis of the free NiFe layer with the longitudinal direction of device.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.147-153
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• 2011

This study is to measure the differences of the trace-metals resulted from the different ecologies, such as nickel(Ni), copper(Cu), zinc(Zn), cadmium(Cd), plumbum(Pb), arsenic(As) and chrome(Cr) remaining in the parts of Korean Yeongdeok Crab (KYC) and Russian Snow Crab (RSC) based on ICP-MS. The recovery rate of each metal certified the reference materials (CRM) was in the average of 81~99%, which corresponded with the level required in Codex. The level of metals in the parts of KYC was in the order of Ni > As > Zn > Cu > Cr > Cd in the both male and female shell; the order of Zn > As > Cu > Cr > Ni > Cd in the leg flesh; the order of Zn > As > Cu > Cr > Cd > Ni in the body flesh; the order of Cu > Zn > As > Cd > Cr > Ni in the gill; the order of Cu > As > Zn > Cd > Ni > Cr in the male hepatopancreas; the order of Cu > Zn > As > Cd > Cr > Ni in the female hepatopancreas, thereby showing some differences. It was revealed that the levels of most metals (nickel, copper, zinc, arsenic and chrome) were similar between KYC and RSC except cadmium which was somewhat lower than that of KYC. However, the cadmium in RSC was discovered in high level in most of the parts, two times higher in the hepatopancreas, and four times in the gill. It was also revealed that the trace metal contents were changing according to the size of KYC; the metals with the highest level of Ni in shell, Zn in leg and body flesh, Cu in gill tended to decrease as growing, whereas the cadmium contents tended to increase overall and accumulated the most in hepatopancreas. The results showed there was a possibility that the phenomenon of bioaccumulation within hepatopancreas would increase as growing.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.45-45
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• 1994

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.222-223
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• 2003

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.1
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• pp.33-37
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• 2008

The effects of Cu and Sb on the microstructure and mechanical properties of Sn-Sb-Cu-Ni-Cd whitemetal were investigated. Any compound phase was not observed in the whitemetal with 0.05 wt% Cu, while as the Cu content was increased, star- or needle-like $Cu_6Sn_5$ phases were found. The tensile strength gradually increased with Cu up to 5 % and then remained almost constant with Cu content above 5 %, while the hardness continuously increased with Cu content because of the increased hard $Cu_6Sn_5$ phases. As the Sb content increased, SbSn cuboids were present as well as $Cu_6Sn_5$. The tensile steength and hardness continuously increased and the elongation decreased with Sb content.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.231-231
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• 2015

무전해 Ni의 Metal turnover (MTO)가 증가함에 따라, Ni과 Sn-Ag-Cu솔더간 계면 금속간화합물층의 두꺼워지고, Ni-Sn-P층에 형성된 Nano void의 수가 많아지게 되어 취성파괴가 증가한다.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.29-34
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• 2020

The behavior of brittle fracture of electroless nickel immersion gold (ENIG) /Sn-3.0wt.%Ag-0.5wt.%Cu (SAC305) solder joints was evaluated. The pH of the electroless nickel plating solution for ENIG surface treatment was changed from 4.0 to 5.5. As the pH of the Ni plating solution increased, pin hole in the Ni-P layer increased. The thickness of the interfacial intermetallic compound (IMC) of the solder joint increased with pH of Ni plating solution. The high speed shear strength of the SAC305 solder joint on ENIG surface finish decreased with the pH of the Ni plating solution. In addition, the brittle fracture rate of the solder joint was the highest when the pH of the Ni plating solution was 5.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.2
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• pp.79-85
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• 2024

The effects of annealing heat treatment and the addition of Cu element on the shape memory effect of the NiTi-based alloy were investigated by analyzing differential scanning calorimeter results and characterizing recovery rate through 3D scanning after Vickers hardness test. Through 3D scanning of impressions after Vickers hardness test, the strain recovery rates for specimens without annealing treatment and annealed specimens at 400, 450, and 500℃ were measured as 45.96%, 46.76%, 52.37%, and 43.57%, respectively. This is because as the annealing temperature increases, both B19' and NiTi₂ phases, which can impede martensitic transformation, are incorporated within the NiTi matrix. Particularly, additional phase transformation from R-phase to B19' observed in specimens annealed at 400 and 450℃ significantly contributes to the improvement in strain recovery rates. Additionally, the results regarding the Cu element content indicate that when the total content of Ni and Cu is below 49.6 at.%, the precipitation of fine B19' and NiTi₂ phases within the matrix can greatly influence the transformation enthalpy and temperature range, resulting in relatively lower strain recovery rates in NiTi alloys with a small amount of Cu element produced in this study.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.288-294
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• 1998

Effect of degree of intermixing at the Ta/NiFe interface induced by varying applied substrate bias voltage during NiFe free layer deposition on change of magnetoresistance in Substrate/Ta/NiFe/Cu/NiFe/FeMn/Ta spin valve multilayers was investigated. It was found that the optimum NiFe free layer thickness showing a maximum MR increase with increasing the bias voltage. The increase of the optimum thickness was due to the increase of the intermixed layer thickness with a bias voltage. The weak ferromagnetic or non ferromagnetic intermixed layer plays as a spin-independent scattering region and does not contribute on spin-dependent scattering. The existence of the intermixed layer was proved by the means of electrical resistivity and magnetization changes. In the present study, the optimum "effective" free layer thickness which gives the highest MR ratio was a constant independent of the magnitude of the bias voltage we have used.have used.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.450-455
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• 2002

Cu-cored Sn-Ag solder balls were fabricated by coating pure Sn and Ag on Cu balls. The melting behavior and the solderability of the BGA joint with the Ni/Au coated Cu pad were investigated and were compared with those of the commercial Sn-Ag and Sn-Ag-Cu balls. DSC analyses clarified the melting of Cu-cored solders to start at a rather low temperature, the eutectic temperature of Sn-Ag-Cu. It was ascribed to the diffusion of Cu and Ag into Sn plating during the heating process. After reflow soldering the microstructures of the solder and of the interfacial layer between the solder and the Cu pad were analyzed with SEM and EPMA. By EDX analysis, formation of a eutectic microstructure composing of $\beta$-Sn, Ag$_3$Sn, ad Cu$_{6}$Sn$_{5}$ phases was confirmed in the solder, and the η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer was found to form at the interface between the solder and the Cu pad. By conducting shear tests, it was found that the BGA joint using Cu-cored solder ball could prevent the degradation of joint strength during aging at 423K because of the slower growth me of η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer formed at the solder, pad interface. Furthermore, Cu-cored multi-component Sn-Ag-Bi balls were fabricated by sequentially coating the binary Sn-Ag and Sn-Bi solders on Cu balls. The reflow property of these solder balls was investigated. Melting of these solder balls was clarified to start at the almost same temperature as that of Sn-2Ag-0.75Cu-3Bi solder. A microstructure composing of (Sn), Ag$_3$Sn, Bi and Cu$_{6}$Sn$_{5}$ phases was found to form in the solder ball, and a reaction layer containing primarily η'-(Au, Co, Cu, Ni)$_{6}$Sn$_{5}$ was found at the interface with Ni/Au coated Cu pad after reflow soldering. By conducting shear test, it was found that the BGA joints using this Cu-core solder balls hardly degraded their joint shear strength during aging at 423K due to the slower growth rate of the η'-(Au, Cu, Ni)$_{6}$Sn$_{5}$ reaction layer at the solder/pad interface.he solder/pad interface.