• Title/Summary/Keyword: Silver Soldering

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Interfacial Elemental Change When Soldering the Nico-crally and Fe-Cr-Ni Alloy (국소의치금속상과 Fe-Cr계 wire를 soldering 할때 발생한 계면의 성분변화)

  • Cho, Sung-Am;Ko, Hyun-Kwon
    • The Journal of Korean Academy of Prosthodontics
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    • v.27 no.1
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    • pp.49-54
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    • 1989
  • The purpose of this study was to investigate the interfacial elemental change when solding the Ni-Co-Cr dental removable partial denture alloy and Fe-Cr-Ni wrought wire alloy with Ag-Cu-Zu Silver solder, by EDXA, EPMA, to investigate the appropriateness of clinical usefullness for repair the fractured clasps of removable partial dentive. The result of this study was as follows: 1. The Ni element of major component of Ticonium penetrate into the silver solder 2. The movement Age element of silver solder into Fe-Cr-Ni wire was not significant, by EDXA and EPMA.

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Chronic Cadmium Intoxication and Renal Injury Among Workers of a Small-scale Silver Soldering Company

  • Choi, Won-Jun;Kang, Seong-Kyu;Ham, Seunghon;Chung, Wookyung;Kim, Ae Jin;Kang, Myunghee
    • Safety and Health at Work
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    • v.11 no.2
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    • pp.235-240
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    • 2020
  • Background: Cadmium exposure may induce chronic intoxication with renal damage. Silver soldering may be a source of cadmium exposure. Methods: We analyzed working environment measurement data and periodic health screening data from a small-scale silver soldering company with ten workers. Concentrations of cadmium in air from working environment measurement data were obtained. Concentrations of blood and urinary cadmium, urine protein, and urine β2-microglobulin (β2M) were obtained. The generalized linear model was used to identify the association between blood and urine cadmium and urine β2M concentrations. Clinical features of chronic cadmium intoxication focused with toxicological renal effects were described. Results: The mean duration of work was 8.5 years (standard deviation [SD] = 6.9, range = 3-20 years). Cadmium concentrations in air were ranged from 0.006 to 0.015 mg/㎥. Blood cadmium concentration was elevated in all ten workers, with a highest level of 34.6 ㎍/L (mean = 21.288 ㎍/L, SD = 11.304, range = 9.641-34.630 ㎍/L). Urinary cadmium concentration was elevated in nine workers, with a highest level of 62.9 ㎍/g Cr (mean = 22.151 ㎍/g creatinine, SD = 19.889, range = 3.228-62.971 ㎍/g creatinine). Urine β2M concentration was elevated in three workers. Urinary cadmium concentration was positively associated with urine protein concentration (beta coefficient = 10.27, 95% confidence interval = [4.36, 16.18]). Other clinical parameters were compatible with renal tubular damage. Conclusion: Cadmium intoxication may occur at quite low air concentrations. Exposure limit may be needed to be lowered.

Development on New Laser Tabbing Process for Modulation of Thin Solar Cell (박형 태양 전지 모듈화를 위한 레이져 태빙 자동화 공정(장비) 개발)

  • No, Donghun;Choi, Chul-June;Cho, Hyun Young;Yu, Jae Min;Kim, JungKeun
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.58.1-58.1
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    • 2010
  • In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.

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Jangdo(Small Ornamental Knives) manufacturing process and restoration research using Odong Inlay application (오동상감(烏銅象嵌)기법을 활용한 장도(粧刀)의 제작기술 및 복원연구)

  • Yun, Yong Hyun;Cho, Nam Chul;Jeong, Yeong Sang;Jang, Chu Nam
    • Korean Journal of Heritage: History & Science
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    • v.49 no.2
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    • pp.172-189
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    • 2016
  • In this research, literature research on the Odong material, mixture ratio, casting method and casting facility was conducted on contemporary documents, such as Cheongong Geamul. Also, a long sword was produced using the Odong inlay technique. The sword reproduction steps were as follows; Odong alloying, silver soldering alloying, Odong plate and Silver plate production, hilt and sheath production, metal frame and decorative elements, such as a Dugup (metal frame), production, Odong inlay assembly and final assembly. For the Odong alloy production, the mixture ratio of the true Odong, which has copper and gold ratio of 20:1, was used. This is traditional ratio for high quality product according to $17^{th}$ century metallurgy instruction manual. The silver soldering alloy was produced with silver and brass(Cu 7 : Zn 3) ratio of 5:1 for inlay purpose and 5:2 ratio for simple welding purpose. The true Odong alloy laminated with silver plate was used to produce hilt and sheath. The alloy went through annealing and forging steps to make it into 0.6 mm thick plate and its backing layer, which is a silver plate, had the matching thickness. After the two plates were adhered, the laminated plate went through annealing, forging, engraving, silver inlaying, shaping, silver welding, finishing and polishing steps. During the Odong colouring process, its red surface turns black by induced corrosion and different hues can be achieved depending on its quality. To accomplish the silver inlay Odong techniques, a Hanji saturated with thirty day old urine is wrapped around a hilt and sheath material, then it is left at warm room temperature for two to three hours. The Odong's surface will turn black when silver inlay remains unchanged. Various scientific analysis were conducted to study composition of recreated Odong panel, silver soldering, silver plate and the colouring agent on Odong's surface. The recreated Odong had average out at Cu 95.57 wt% Au 4.16wt% and Cu 98.04 wt% Au 1.95wt%, when documented ratio in the old record is Cu 95wt% and Au 5wt%. The recreated Odong was prone to surface breakage during manufacturing process unlike material made with composition ratio written in the old record. On the silver plate of the silver and Odong laminate, 100wt% Ag was detected and between the two layers Cu, Ag and Au were detected. This proves that the adhesion between the two layers was successfully achieved. The silver soldering had varied composition of Ag depending on the location. This shows uneven composition of the silver welding. A large quantities of S, that was not initially present, was detected on the surface of the black Odong. This indicates that presence of S has influence on Odong colour. Additional study on the chromaticity, additional chemical compounds and its restoration are needed for the further understanding of the origin of Odong colour. The result of Odong alloy testing and recreation, Odong silver inlay long sword production, scientific analysis of the Odong black colouring agent will form an important foundation of knowledge for conservation of Odong artifact.

Lower Temperature Soldering of Capacitor Using Sn-Bi Coated $Sn-3.5\%Ag$ Solder (Sn-Bi도금 $Sn-3.5\%Ag$ 솔더를 이용한 Capacitor의 저온 솔더링)

  • Kim Mi-Jin;Cho Sun-Yun;Kim Sook-Hwan;Jung Jae-Pil
    • Journal of Welding and Joining
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    • v.23 no.3
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    • pp.61-67
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    • 2005
  • Since lead (Pb)-free solders for electronics have higher melting points than that of eutectic Sn-Pb solder, they need higher soldering temperatures. In order to decrease the soldering temperature we tried to coat Sn-Bi layer on $Sn-3.5\%Ag$ solder by electroplating, which applies the mechanism of transient liquid phase bonding to soldering. During heating Bi will diffuse into the $Sn-3.5\%Ag$ solder and this results in decreasing soldering temperature. As bonding samples, the 1608 capacitor electroplated with Sn, and PCB, its surface was finished with electroless-plated Ni/Au, were selected. The $Sn-95.7\%Bi$ coated Sn-3.5Ag was supplied as a solder between the capacitor and PCB land. The samples were reflowed at $220^{\circ}C$, which was lower than that of normal reflow temperature, $240\~250^{\circ}C$, for the Pb-free. As experimental result, the joint of $Sn-95.7\%Bi$ coated Sn-3.5Ag showed high shear strength. In the as-reflowed state, the shear strength of the coated solder showed 58.8N, whereas those of commercial ones were 37.2N (Sn-37Pb), 31.4N (Sn-3Ag-0.5Cu), and 40.2N (Sn-8Zn-3Bi). After thermal shock of 1000 cycles between $-40^{\circ}C$ and $+125^{\circ}C$, shear strength of the coated solder showed 56.8N, whereas the previous commercial solders were in the range of 32.3N and 45.1N. As the microstructures, in the solder $Ag_3Sn$ intermetallic compound (IMC), and along the bonded interface $Ni_3Sn_4$ IMC were observed.

Effects of the Atmosphere on the Comparative Solderability of Lead-Tin and Lead-Free Solders

  • Bin, Jeong-Uk;S.M.Adams;P.F.Stratton
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2001.04a
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    • pp.45-47
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    • 2001
  • Due to pressure from threatened legislation in Europe, consumer and governmental pressure in Japan, and glob머 market considerations in the US, there is a rapidly growing interest in lead-free solderinger, Although the move to lead free soldering seems inevitable, many problems will arise in production assembly. It is generally acknowledged that the lead-free solders available offer a much s smaller process window than lead/tin, related mainly to the higher soldering temperatures which naturally result from increases of liquidus temperatures of at least 300 C. However, raising reflow temperatures from the current 220-2300 C to 250 2600 C will lead to problems with the boards and components as well as i increasing oxidation effects. There is a need to keep reflow temperatures low without reducing solderablity. Some results on benefits of inert atmospheres are discussed in this paper. For example, testing in a nitrogen atmosphere, with 300 ppm oxygen, by the N National Physical Laboratory (NPU has revealed clear benefits for ine$\pi$mg lead-free alloys, by restoring the solderability to lead/tin levels, by enabling lower soldering temperatures. However, there has been little testing over a range of oxygen levels in nitrogen and this is an important issue in determining n nitrogen supply and oven costs. Some results are reported here from work by NPL conducted for BOC in w which solderability was evaluated for tin기ead and tin/silver/copper eutectic a alloys in a wetting balance over a range of oxygen levels form 10 ppm to 21% ( (air). The studies confirm that acceptable wetting times occur in inert atmospheres a at soldering temperatures 20 to 300 C lower than are possible in air.

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Properties of Ag Thick Films Fabricated by Using Low Temperature Curable Ag Pastes (저온 경화형 Ag 페이스트 및 이를 이용한 Ag 후막의 제조 및 특성)

  • Park, Joon-Shik;Hwang, Joon-Ho;Kim, Jin-Gu;Kim, Yong-Han;Park, Hyo-Derk;Kang, Sung-Goon
    • Korean Journal of Materials Research
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    • v.13 no.1
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    • pp.18-23
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    • 2003
  • Properties of Ag thick films fabricated by using low temperature curable silver pastes were investigated. Ag pastes were consisted of polymer resins and silver powders. Ag pastes were used for conductive or fixing materials between board and various electrical and electronic devices. Low temperature curable Ag pastes have some advantages over high temperature curable types. In cases of chip mounting, soldering properties were required for screen printed Ag thick films. In this study, four types of Ag pastes were fabricated with different compositions. Screen printed Ag thick films on alumina substrates were fabricated at various curing temperatures and times. Thickness, resistivity, adhesive strength and solderability of fabricated Ag thick films were characterized. Finally, Ag thick films produced using Ag pastes, sample A and B, cured at $150^{\circ}C$ for longer than 6 h and $180^{\circ}C$ for longer than 2 h, and $150^{\circ}C$ for longer than 1 h and $180^{\circ}C$ for 1 h, respectively, showed low resistivities of $10^{-4}$ $∼10^{-5}$ Ωcm and good adhesive strength of 1∼5 Mpa. Soldering properties of those Ag thick films with curing temperatures at solder of 62Sn/36Pb/3Ag were also investigated.

A Study on Handiwork Technique of Filigree Artifacts Excavated from Neungsan-ri Temple Site in Buyeo, Korea (부여 능산리사지 출토 누금세공 유물의 제작기술 연구)

  • Lee, Sun-Myung;Kung, Seung-Nam;Kim, Yeon-Mi
    • Journal of Conservation Science
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    • v.26 no.1
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    • pp.13-24
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    • 2010
  • This study examined each handiwork method of 4 filigree artifacts from Neungsan-ri temple site in Buyeo, Korea through material characteristic and microstructure analysis. As a result, it was indicated that all of the artifacts have comparatively higher purity than 22.7K and some of filigree artifacts showed that gold is alloyed with silver at a certain ratio. Gold thread that decorates surface showed thickness of 0.2~0.8mm and displayed various forms of section. Gold granule indicated that 2 or 3 granules are adhered together and they are 0.3~0.8mm in diameter. Trace of soldering was observed from gold thread and gold granule joints on surface and it confirmed a possibility of being soldering using gold solder through componential analysis. Also, it reveals a surface decorated with pigments such as cinnabar(HgS) and black.

Flip Chip Solder Joint Reliability of Sn-3.5Ag Solder Using Ultrasonic Bonding - Study of the interface between Si-wafer and Sn-3.5Ag solder (초음파를 이용한 Sn-3.5Ag 플립칩 접합부의 신뢰성 평가 - Si웨이퍼와 Sn-3.5Ag 솔더의 접합 계면 특성 연구)

  • Kim Jung-Mo;Kim Sook-Hwan;Jung Jae-Pil
    • Journal of the Microelectronics and Packaging Society
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    • v.13 no.1 s.38
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    • pp.23-29
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    • 2006
  • Ultrasonic soldering of Si-wafer to FR-4 PCB at ambient temperature was investigated. The UBM of Si-substrate was Cu/ Ni/ Al from top to bottom with thickness of $0.4{\mu}m,\;0.4{\mu}m$, and $0.3{\mu}m$ respectively. The pad on FR-4 PCB comprised of Au/ Ni/ Cu from top to bottom with thickness of $0.05{\mu}m,\;5{\mu}m$, and $18{\mu}m$ respectively. Sn-3.5wt%Ag foil rolled to $100{\mu}m$ was used for solder. The ultrasonic soldering time was varied from 0.5 s to 3.0 s and the ultrasonic power was 1,400 W. The experimental results show that a reliable bond by ultrasonic soldering at ambient temperature was obtained. The shear strength increased with soldering time up to a maximum of 65 N at 2.5 s. The strength decreased to 34 N at 3.0 s because cracks were generated along the intermetallic compound between Si-wafer and Sn-3.5wt%Ag solder. The Intermetallic compound produced by ultrasonic soldering between the Si-wafer and the solder was $(Cu,Ni)_{6}Sn_{5}$.

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Window Integrated Solar Collectors (창호일체형 태양열 집열기)

  • Park, Seong-Bae;Lim, Seong-Whan;Park, Mann-Kwi
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.61-65
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    • 2009
  • Window integrated solar collector is to simply install inside of the existing double glass window frame. Double glass window frame is consist of inner glass of Low-E coating and Silver coating, and outer glass of low iron reinforced glass. In order to secure natural lighting in a room, only 50% of window frame is covered with solar collectors. Solar absorption or transmission rate varies seasonally depending on sun angles. Part of inner glass where right behind of the solar plate is covered with silver coating to increase absorption rate of solar plate. The collector is made of a copper serpentine where aluminum fins are soldering. To improve the effect of insulation of inside of the window frame is recommend vacuum. As a result, we are making the 3th sample and will archieve below $F_RU_L=7.5W/m^2^{\circ}C$ that is the account of heat lossed, and above $F_R({\tau}{\alpha})=0.45$.

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