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Sample records for solder plate lead

  1. In-situ Investigation of Lead-free Solder Alloy Formation Using a Hot-plate Microscope

    DEFF Research Database (Denmark)

    Bergmann, René; Tang, Peter Torben; Hansen, Hans Nørgaard

    2007-01-01

    This work presents the advantages of using a hot-plate microscope for investigation of new (high-temperature) lead- free solders as in-situ analysis tool and preparation equipment. A description of the equipment and the preparation method is given and some examples are outlined. The formation...

  2. Lead free solder mechanics and reliability

    CERN Document Server

    Pang, John Hock Lye

    2012-01-01

    Lead-free solders are used extensively as interconnection materials in electronic assemblies and play a critical role in the global semiconductor packaging and electronics manufacturing industry. Electronic products such as smart phones, notebooks and high performance computers rely on lead-free solder joints to connect IC chip components to printed circuit boards. Lead Free Solder: Mechanics and Reliability provides in-depth design knowledge on lead-free solder elastic-plastic-creep and strain-rate dependent deformation behavior and its application in failure assessment of solder joint reliability. It includes coverage of advanced mechanics of materials theory and experiments, mechanical properties of solder and solder joint specimens, constitutive models for solder deformation behavior; numerical modeling and simulation of solder joint failure subject to thermal cycling, mechanical bending fatigue, vibration fatigue and board-level drop impact tests. This book also: Discusses the mechanical prope...

  3. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Science.gov (United States)

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

    2004-10-01

    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  4. A novel method for direct solder bump pull testing using lead-free solders

    Science.gov (United States)

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

  5. Characterization of lead-free solders for electronic packaging

    Science.gov (United States)

    Ma, Hongtao

    The characterization of lead-free solders, especially after isothermal aging, is very important in order to accurately predict the reliability of solder joints. However, due to lack of experimental testing standards and the high homologous temperature of solder alloys (Th > 0.5T m even at room temperature), there are very large discrepancies in both the tensile and creep properties provided in current databases for both lead-free and Sn-Pb solder alloys. In this research, mechanical measurements of isothermal aging effects and the resulting changes in the materials behavior of lead-free solders were performed. A novel specimen preparation procedure was developed where the solder uniaxial test specimens are formed in high precision rectangular cross-section glass tubes using a vacuum suction process. Using specimens fabricated with the developed procedure, isothermal aging effects and viscoplastic material behavior evolution have been characterized for 95.5Sn-4.0Ag-0.5Cu (SAC405) and 96.5Sn-3.0Ag-0.5Cu (SAC305) lead-free solders, which are commonly used as the solder ball alloy in lead-free BGAs and other components. Analogous tests were performed with 63Sn-37Pb eutectic solder samples for comparison purposes. Up to 40% reduction in tensile strength was observed for water quenched specimens after two months of aging at room temperature. Creep deformation also increased dramatically with increasing aging durations. Microstructural changes during room temperature aging were also observed and recorded for the solder alloys and correlated with the observed mechanical behavior changes. Aging effects at elevated temperatures for up to 6 months were also investigated. Thermal aging caused significant tensile strength loss and deterioration of creep deformation. The thermal aging results also showed that after an initial tensile strength drop, the Sn-Pb eutectic solder reached a relatively stable stage after 200 hours of aging. However, for SAC alloy, both the tensile and

  6. Drinking Water Contamination Due To Lead-based Solder

    Science.gov (United States)

    Garcia, N.; Bartelt, E.; Cuff, K. E.

    2004-12-01

    The presence of lead in drinking water creates many health hazards. Exposure to lead-contaminated water can affect the brain, the central nervous system, blood cells, and kidneys, causing such problems as mental retardation, kidney disease, heart disease, stroke, and death. One way in which lead can contaminate our water supply is through the use of lead solder to join pipes. Lead solder was widely used in the past because of its ease of application as well as its low cost. Lead contamination in residential areas has previously been found to be a particularly serious problem in first-draw samples, of water that has sat stagnant in pipes overnight. To investigate the time-dependence of drinking water lead contamination, we analyzed samples taken hourly of water exposed to lead solder. While our preliminary data was insufficient to show more than a rough correlation between time of exposure and lead concentration over short periods (1-3 hours), we were able to confirm that overnight exposure of water to lead-based solder results in the presence high levels of lead. We also investigated other, external factors that previous research has indicated contribute to increased concentrations of lead. Our analysis of samples of lead-exposed water at various pH and temperatures suggests that these factors can be equally significant in terms of their contribution to elevated lead concentration levels. In particular, water that is slightly corrosive appears to severely impact the solubility of lead. As this type of water is common in much of the Northeast United States, the presence of lead-based solder in residential areas there is especially problematic. Although lead-based solder has been banned since the 1980s, it remains a serious concern, and a practical solution still requires further research.

  7. Lead-free solder technology transfer from ASE Americas

    Energy Technology Data Exchange (ETDEWEB)

    FTHENAKIS,V.

    1999-10-19

    To safeguard the environmental friendliness of photovoltaics, the PV industry follows a proactive, long-term environmental strategy involving a life-of-cycle approach to prevent environmental damage by its processes and products from cradle to grave. Part of this strategy is to examine substituting lead-based solder on PV modules with other solder alloys. Lead is a toxic metal that, if ingested, can damage the brain, nervous system, liver and kidneys. Lead from solder in electronic products has been found to leach out from municipal waste landfills and municipal incinerator ash was found to be high in lead also because of disposed consumer electronics and batteries. Consequently, there is a movement in Europe and Japan to ban lead altogether from use in electronic products and to restrict the movement across geographical boundaries of waste containing lead. Photovoltaic modules may contain small amounts of regulated materials, which vary from one technology to another. Environmental regulations impact the cost and complexity of dealing with end-of-life PV modules. If they were classified as hazardous according to Federal or State criteria, then special requirements for material handling, disposal, record-keeping and reporting would escalate the cost of decommissioning the modules. Fthenakis showed that several of today's x-Si modules failed the US-EPA Toxicity Characteristic Leaching Procedure (TCLP) for potential leaching of Pb in landfills and also California's standard on Total Threshold Limit Concentration (TTLC) for Pb. Consequently, such modules may be classified as hazardous waste. He highlighted potential legislation in Europe and Japan which could ban or restrict the use of lead and the efforts of the printed-circuit industries in developing Pb-free solder technologies in response to such expected legislation. Japanese firms already have introduced electronic products with Pb-free solder, and one PV manufacturer in the US, ASE Americas has used a

  8. Soluble Lead and Bismuth Chalcogenidometallates: Versatile Solders for Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [Department; Son, Jae Sung [Department; School; Dolzhnikov, Dmitriy S. [Department; Filatov, Alexander S. [Department; Hazarika, Abhijit [Department; Wang, Yuanyuan [Department; Hudson, Margaret H. [Department; Sun, Cheng-Jun [Advanced; Chattopadhyay, Soma [Physical; Talapin, Dmitri V. [Department; Center

    2017-07-27

    Here we report the syntheses of largely unexplored lead and bismuth chalcogenidometallates in the solution phase. Using N2H4 as the solvent, new compounds such as K6Pb3Te6·7N2H4 were obtained. These soluble molecular compounds underwent cation exchange processes using resin chemistry, replacing Na+ or K+ by decomposable N2H5+ or tetraethylammonium cations. They also transformed into stoichiometric lead and bismuth chalcogenide nanomaterials with the addition of metal salts. Such a versatile chemistry led to a variety of composition-matched solders to join lead and bismuth chalcogenides and tune their charge transport properties at the grain boundaries. Solution-processed thin films composed of Bi0.5Sb1.5Te3 microparticles soldered by (N2H5)6Bi0.5Sb1.5Te6 exhibited thermoelectric power factors (~28 μW/cm K2) comparable to those in vacuum-deposited Bi0.5Sb1.5Te3 films. The soldering effect can also be integrated with attractive fabrication techniques for thermoelectric modules, such as screen printing, suggesting the potential of these solders in the rational design of printable and moldable thermoelectrics.

  9. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Directory of Open Access Journals (Sweden)

    Liu Mei Lee

    2013-01-01

    Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

  10. High-Temperature Lead-Free Solder Alternatives: Possibilities and Properties

    DEFF Research Database (Denmark)

    High-temperature solders have been widely used as joining materials to provide stable interconnections that resist a severe thermal environment and also to facilitate the drive for miniaturization. High-lead containing solders have been commonly used as high-temperature solders. The development...... of high-temperature lead-free solders has become an important issue for both the electronics and automobile industries because of the health and environmental concerns associated with lead usage. Unfortunately, limited choices are available as high-temperature lead-free solders. This work outlines...... the criteria for the evaluation of a new high-temperature lead-free solder material. A list of potential ternary high-temperature lead-free solder alternatives based on the Au-Sn and Au-Ge systems is proposed. Furthermore, a comprehensive comparison of the high-temperature stability of microstructures...

  11. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... other industries due to its low cost and unique material properties like low melting point, avail- ability etc. However, the toxicity of lead during industrial production of components and the ... Companies in other countries. (for instance, many in the Japanese electronics in- dustries) began to introduce some ...

  12. Reliability of lead-free solder joints with different PCB surface finishes under thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Xia Yanghua [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: xia_yanghua@hotmail.com; Xie Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2008-04-24

    The reliability of lead-free electronic assemblies under thermal cycling was investigated. Thin small outline package (TSOP) devices with FeNi leads were reflow soldered on FR4 PCB (printed circuit board) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes (organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)) were studied. The results show that OSP finish reveals better performance than its ENIG counterparts. The crack originates at the fringe of heel fillet in both cases. The propagation of crack in the ENIG case is along the device/solder interface, while in the case of OSP, the crack extends parallel to the solder/PCB interface. When the OSP finishes are employed, many Cu6Sn5 precipitates form inside the bulk solder and have a strengthening effect on the solder joint, resulting in better reliability performance as compared to those with ENIG finishes.

  13. Corrosive microenvironments at lead solder surfaces arising from galvanic corrosion with copper pipe.

    Science.gov (United States)

    Nguyen, Caroline K; Stone, Kendall R; Dudi, Abhijeet; Edwards, Marc A

    2010-09-15

    As stagnant water contacts copper pipe and lead solder (simulated soldered joints), a corrosion cell is formed between the metals in solder (Pb, Sn) and the copper. If the resulting galvanic current exceeds about 2 μA/cm(2), a highly corrosive microenvironment can form at the solder surface, with pH chloride concentrations at least 11 times higher than bulk water levels. Waters with relatively high chloride tend to sustain high galvanic currents, preventing passivation of the solder surface, and contributing to lead contamination of potable water supplies. The total mass of lead corroded was consistent with predictions based on the galvanic current, and lead leaching to water was correlated with galvanic current. If the concentration of sulfate in the water increased relative to chloride, galvanic currents and associated lead contamination could be greatly reduced, and solder surfaces were readily passivated.

  14. An Approach for Impression Creep of Lead Free Microelectronic Solders

    Science.gov (United States)

    Anastasio, Onofrio A.

    2002-06-01

    Currently, the microelectronics industry is transitioning from lead-containing to lead-free solders in response to legislation in the EU and Japan. Before an alternative alloy can be designated as a replacement for current Pb-Sn extensive testing must be accomplished. One major characteristic of the alloy that must be considered is creep. Traditionally, creep testing requires numerous samples and a long tin, which thwarts the generation of comprehensive creep databases for difficult to prepare samples such as microelectronic solder joints. However, a relatively new technique, impression creep enables us to rapidly generate creep data. This test uses a cylindrical punch with a flat end to make an impression on the surface of a specimen under constant load. The steady state velocity of the indenter is found to have the same stress and temperature dependence as the conventional unidirectional creep test using bulk specimens. This thesis examines impression creep tests of eutectic Sn-Ag. A testing program and apparatus was developed constructed based on a servo hydraulic test frame. The apparatus is capable of a load resolution of 0.01N with a stability of plus/minus 0.1N, and a displacement resolution of 0.05 microns with a stability of plus/minus 0.1 microns. Samples of eutectic Sn-Ag solder were reflowed to develop the microstructure used in microelectronic packaging. Creep tests were conducted at various stresses and temperatures and showed that coarse microstructures creep more rapidly than the microstructures in the tested regime.

  15. Investigation on solder joint strength of nickel tin-plated and CRS tabs with PCB

    International Nuclear Information System (INIS)

    Luay Hussain

    2002-01-01

    Failure analysis on easily peels off Nickel and CRS steel tabs from PCB was carried out. Nickel Tin plated tabs, CRS steel tabs and tube were joined to the PCB using reflow/ convection soldering, in an oven. The solder paste composition is Sn36/Pb35/Ag2. Peel test was conducted and it was found that many tabs could be easily peeled off with low force. Porosities which varies from 0.4 mm to < 0.01mm in diameter, developed during soldering process and solidification was noted. It was found, the number, size and position of these porosities inside the solder layer on both parts of the tabs affect the peel strength. Scanning Electron Microscopy study and EDX analysis were carried out. It was found that the low peel strength values were due to the combination of generation and development of porosities during soldering process which act as stress concentrators and the evolution (growth) of eutectic Sn/Pb and Sn/Ni/Cu brittle grainy phase. Large eutectic microstructure with brittle Sn-Ni-Cu grainy phase enhances the failure with low peeling forces. Sample showing no feature of Sn/Ni/Cu grain gave high peeling strength value. Solder reflow, an important process, can result in strength enhancement (if it was controlled for example in a furnace). (Author)

  16. Current Problems and Possible Solutions in High-Temperature Lead-Free Soldering

    Czech Academy of Sciences Publication Activity Database

    Kroupa, Aleš; Andersson, D.; Hoo, N.; Pearce, J.; Watson, A.; Dinsdale, A.; Mucklejohn, S.

    2012-01-01

    Roč. 21, č. 5 (2012), s. 629-637 ISSN 1059-9495 Institutional support: RVO:68081723 Keywords : lead-free soldering, * materials for high-temperature LF * new technologies for HT lead-free soldering Subject RIV: BJ - Thermodynamics Impact factor: 0.915, year: 2012

  17. Physical properties of lead free solders in liquid and solid state

    Energy Technology Data Exchange (ETDEWEB)

    Mhiaoui, Souad

    2007-04-17

    The European legislation prohibits the use of lead containing solders in Europe. However, lead free solders have a higher melting point (typical 20%) and their mechanical characteristics are worse. Additional problems are aging and adhesion of the solder on the electronic circuits. Thus, research activities must focus on the optimization of the properties of Sn-Ag-Cu based lead free solders chosen by the industry. Two main objectives are treated in this work. In the center of the first one is the study of curious hysteresis effects of metallic cadmium-antimony alloys after thermal cycles by measuring electronic transport phenomena (thermoelectric power and electrical resistivity). The second objective, within the framework of ''cotutelle'' between the universities of Metz and of Chemnitz and supported by COST531, is to study more specifically lead free solders. A welding must well conduct electricity and well conduct and dissipate heat. In Metz, we determined the electrical conductivity, the thermoelectric power and the thermal conductivity of various lead free solders (Sn-Ag-Cu, Sn-Cu, Sn-Ag, Sn-Sb) as well in the liquid as well in the solid state. The results have been compared to classical lead-tin (Pb-Sn) solders. In Chemnitz we measured the surface tension, the interfacial tension and the density of lead free solders. We also measured the viscosity of these solders without and with additives, in particular nickel. These properties were related to the industrial problems of wettability and spreadability. Lastly, we solidified alloys under various conditions. We observed undercooling. We developed a technique of mixture of nanocrystalline powder with lead free solders ''to sow'' the liquid bath in order to obtain ''different'' solids which were examined using optical and electron microscopy. (orig.)

  18. Reliability and microstructure of lead-free solder joints in industrial electronics after accelerated thermal aging

    NARCIS (Netherlands)

    Scaltro, F.; Biglari, M.H.; Kodentsov, A.; Yakovleva, O.; Brom, E.

    2009-01-01

    The reliability of lead-free (LF) solder joints in surface-mounted device components (SMD) has been investigated after thermo-cycle testing. Kirkendall voids have been observed at the interface component/solder together with the formation of fractures. The evolution, the morphology and the elemental

  19. Properties and Microstructures of Sn-Bi-X Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Fan Yang

    2016-01-01

    Full Text Available The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

  20. Effect of Strain Rate on Joint Strength and Failure Mode of Lead-Free Solder Joints

    Science.gov (United States)

    Lin, Jian; Lei, Yongping; Fu, Hanguang; Guo, Fu

    2018-03-01

    In surface mount technology, the Sn-3.0Ag-0.5Cu solder joint has a shorter impact lifetime than a traditional lead-tin solder joint. In order to improve the impact property of SnAgCu lead-free solder joints and identify the effect of silver content on tensile strength and impact property, impact experiments were conducted at various strain rates on three selected SnAgCu based solder joints. It was found that joint failure mainly occurred in the solder material with large plastic deformation under low strain rate, while joint failure occurred at the brittle intermetallic compound layer without any plastic deformation at a high strain rate. Joint strength increased with the silver content in SnAgCu alloys in static tensile tests, while the impact property of the solder joint decreased with increasing silver content. When the strain rate was low, plastic deformation occurred with failure and the tensile strength of the Sn-3.0Ag-0.5Cu solder joint was higher than that of Sn-0.3Ag-0.7Cu; when the strain rate was high, joint failure mainly occurred at the brittle interface layer and the Sn-0.3Ag-0.7Cu solder joint had a better impact resistance with a thinner intermetallic compound layer.

  1. Effect of phosphorus element on the comprehensive properties of Sn-Cu lead-free solder

    International Nuclear Information System (INIS)

    Li Guangdong; Shi Yaowu; Hao Hu; Xia Zhidong; Lei Yongping; Guo Fu

    2010-01-01

    In the present work, the effect of phosphorus on the creep fatigue properties of Sn-Cu eutectic lead-free solder was carried out. The experimental results show that the melting temperature was almost not changed with adding small amount of P element. However, the addition of trace P element led to the decrease in the property of creep fatigue. The fractography analysis by a scanning electron microscopy (SEM) shows that ductile fracture was the dominant failure behavior in the process of creep fatigue test of Sn0.7Cu and Sn0.7Cu0.005P specimens. It should be pointed out that there is significant difference in the fractographs between the joints of Sn0.7Cu solder and Sn0.7Cu0.005P solder. In the fractograph of Sn0.7Cu solder joint, the microstructure is prolonged along testing direction, and the dimples were more than the fractograph of Sn0.7Cu0.005P solder joint. In addition, the voids could be found on the Sn0.7Cu0.005P solder joint, and trace P addition may increase the rate of forming void of Sn0.7Cu solder joint. The voids can potentially lead to crack initiation or propagation sites in the solder joint. As a result, the creep fatigue of solder joint containing P such as Sn0.7Cu0.005P offers worse property compared to Sn0.7Cu solder joint.

  2. Effect of phosphorus element on the comprehensive properties of Sn-Cu lead-free solder

    Energy Technology Data Exchange (ETDEWEB)

    Li Guangdong, E-mail: liguangdong@emails.bjut.edu.c [College of Materials Science and Engineering, Beijing University of Technology, 100 Ping Le Yuan, Chaoyang District, Beijing 100124 (China); Shi Yaowu; Hao Hu; Xia Zhidong; Lei Yongping; Guo Fu [College of Materials Science and Engineering, Beijing University of Technology, 100 Ping Le Yuan, Chaoyang District, Beijing 100124 (China)

    2010-02-18

    In the present work, the effect of phosphorus on the creep fatigue properties of Sn-Cu eutectic lead-free solder was carried out. The experimental results show that the melting temperature was almost not changed with adding small amount of P element. However, the addition of trace P element led to the decrease in the property of creep fatigue. The fractography analysis by a scanning electron microscopy (SEM) shows that ductile fracture was the dominant failure behavior in the process of creep fatigue test of Sn0.7Cu and Sn0.7Cu0.005P specimens. It should be pointed out that there is significant difference in the fractographs between the joints of Sn0.7Cu solder and Sn0.7Cu0.005P solder. In the fractograph of Sn0.7Cu solder joint, the microstructure is prolonged along testing direction, and the dimples were more than the fractograph of Sn0.7Cu0.005P solder joint. In addition, the voids could be found on the Sn0.7Cu0.005P solder joint, and trace P addition may increase the rate of forming void of Sn0.7Cu solder joint. The voids can potentially lead to crack initiation or propagation sites in the solder joint. As a result, the creep fatigue of solder joint containing P such as Sn0.7Cu0.005P offers worse property compared to Sn0.7Cu solder joint.

  3. The effect of graphene on the intermetallic and joint strength of Sn-3.5Ag lead-free solder

    Science.gov (United States)

    Mayappan, R.; Salleh, A.; Andas, J.

    2017-09-01

    Solder has been widely used in electronic industry as interconnection for electronic packaging. European Union and Japan have restricted the use of Sn-Pb solder as it contains lead which can harmful to human health and environment. Due to this, many researches have been done in order to find a suitable replacement for the lead solder. Although many lead-free solders are available, the Sn-3.5Ag solder with the addition of graphene seem to be a suitable candidate. In this study, a 0.07 wt% graphene nanosheet was added into the Sn-3.5Ag solder and this composite solder was prepared under powder metallurgy method. The solder was reacted with copper substrate at 250 °C for one minute. For joint strength analysis, two copper strips were soldered together. The solder joint was aged at temperature 100 °C for 500 hours. Scanning Electron Microscope (SEM) was used to observe the interfacial reaction and Instron machine was used to determine the joint strength. Cu6Sn5 intermetallic layer was formed at the interface between the Cu substrate and the solders. Composite solder showed the retardation of the intermetallic growth compared to the plain solder. The thickness value of the intermetallic was used to calculate the growth rate the IMC. The graphene nanosheets added solder has lower growth rate which is 3.86 × 10-15 cm2/s compared to the plain solder 7.15 × 10-15 cm2/s. Shear strength analysis show that the composite solder has higher joint compared to the plain solder.

  4. Thermomechanical behavior of tin-rich (lead-free) solders

    Science.gov (United States)

    Sidhu, Rajen Singh

    In order to adequately characterize the behavior of ball-grid-array (BGA) Pb-free solder spheres in electronic devices, the microstructure and thermomechanical behavior need to be studied. Microstructure characterization of pure Sn, Sn-0.7Cu, Sn-3.5Ag, and Sn-3.9Ag-0.7Cu alloys was conducted using optical microscopy, scanning electron microscopy, transmission electron microscopy, image analysis, and a novel serial sectioning 3D reconstruction process. Microstructure-based finite-element method (FEM) modeling of deformation in Sn-3.5Ag alloy was conducted, and it will be shown that this technique is more accurate when compared to traditional unit cell models for simulating and understanding material behavior. The effect of cooling rate on microstructure and creep behavior of bulk Sn-rich solders was studied. The creep behavior was evaluated at 25, 95, and 120°C. Faster cooling rates were found to increase the creep strength of the solders due to refinement of the solder microstructure. The creep behavior of Sn-rich single solder spheres reflowed on Cu substrates was studied at 25, 60, 95, and 130°C. Testing was conducted using a microforce testing system, with lap-shear geometry samples. The solder joints displayed two distinct creep behaviors: (a) precipitation-strengthening (Sn-3.5Ag and Sn-3.9Ag-0.7Cu) and (b) power law creep accommodated by grain boundary sliding (GBS) (Sn and Sn-0.7Cu). The relationship between microstructural features (i.e. intermetallic particle size and spacing), stress exponents, threshold stress, and activation energies are discussed. The relationship between small-length scale creep behavior and bulk behavior is also addressed. To better understand the damage evolution in Sn-rich solder joints during thermal fatigue, the local damage will be correlated to the cyclic hysteresis behavior and crystal orientations present in the Sn phase of solder joints. FEM modeling will also be utilized to better understand the macroscopic and local

  5. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Wilfred [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Yusoff, Wan Yusmawati Wan [Universiti Pertahanan Nasional Malaysia, Kem Sg. Besi, 57000 Kuala Lumpur (Malaysia)

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  6. Characterization of the microstructure of tin-silver lead free solder

    Energy Technology Data Exchange (ETDEWEB)

    Hurtony, Tamás, E-mail: hurtony@ett.bme.hu [Department of Electronics Technology, Budapest University of Technology and Economics, Egry József utca 18, Budapest, H-1111 (Hungary); Szakál, Alex; Almásy, László [Neutron Spectroscopy Department, Wigner Research Centre for Physics, Budapest (Hungary); Len, Adél [Neutron Spectroscopy Department, Wigner Research Centre for Physics, Budapest (Hungary); Faculty of Engineering and Information Technology, University of Pécs (Hungary); Kugler, Sándor [Department of Theoretical Physics, Budapest University of Technology and Economics (Hungary); Bonyár, Attila; Gordon, Péter [Department of Electronics Technology, Budapest University of Technology and Economics, Egry József utca 18, Budapest, H-1111 (Hungary)

    2016-07-05

    Reliability and lifetime are the two most relevant design considerations in the production of safety critical assemblies. For example in a modern automobile dozens of electronic assemblies are integrated in which thousands of solder joints are mounting the electronic components to the printed circuit boards. There exists no standardised and universal observation method for characterising the fine microstructure of such solder joints. Previously we have developed a new method for the quantitative characterization of lead-free solder alloys and in present study the validity of the proposed method is demonstrated. Microstructure of Sn-3.5Ag lead free solder alloy was investigated by electrochemical impedance spectroscopy. Solder samples were solidified with different cooling rates in order to induce differences in the microstructure. Microstructure of the ingots was revealed by selective electrochemical etching. Electrochemical impedance spectra (EIS) were measured before and after the selective etching process. The complex impedance spectra contain information about microstructure of the solder alloys. Comparison and modelling of two EIS spectra allowed obtaining a characteristic parameter of surface structure of the etched specimens. The EIS measurements were complemented with small angle neutron scattering measurements and scanning electron microscopy, in order to correlate the EIS parameter with the magnitude of the interface of the β-Sn and Ag{sub 3}Sn phases.

  7. Study on interfacial reaction between lead-free solders and alternative surface finishes

    International Nuclear Information System (INIS)

    Siti Rabiatul Aisha; Ourdjini, A.; Saliza Osman

    2007-01-01

    This study investigates the interfacial reactions occurring during reflow soldering between Sn-Ag-Cu lead-free solder and two surface finishes: electroless nickel/ immersion gold (ENIG) and immersion silver (IAg). The study focuses on interfacial reactions evolution and growth kinetics of intermetallic compounds (IMC) formed during soldering and isothermal ageing at 150 degree Celsius for up to 2000 hours. Optical and scanning electron microscopy were used to measure IMC thickness and examine the morphology of IMC respectively, whereas the IMC phases were identified by energy dispersive X-ray analysis (EDX). The results showed that the IMC formed on ENIG finish is thinner compared to that formed on IAg finish. For IAg surface finish, Cu 6 Sn 5 IMCs with scallop morphology are formed at the solder/ surface finish interface after reflow while a second IMC, Cu 3 Sn was formed between the copper and Cu 6 Sn 5 IMC after the isothermal ageing treatment. For ENIG surface finish both (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 are formed after soldering. Isothermal aging of the solder joints formed on ENIG finish was found to have a significant effect on the morphology of the intermetallics by transforming to more spherical and denser morphology in addition to increase i their thickness with increased ageing time. (author)

  8. Comparative shear tests of some low temperature lead-free solder pastes

    Science.gov (United States)

    Branzei, Mihai; Plotog, Ioan; Varzaru, Gaudentiu; Cucu, Traian C.

    2016-12-01

    The range of electronic components and as a consequence, all parts of automotive electronic equipment operating temperatures in a vehicle is given by the location of that equipment, so the maximum temperature can vary between 358K and 478K1. The solder joints could be defined as passive parts of the interconnection structure of automotive electronic equipment, at a different level, from boards of electronic modules to systems. The manufacturing costs reduction necessity and the RoHS EU Directive3, 7 consequences generate the trend to create new Low-Temperature Lead-Free (LTLF) solder pastes family9. In the paper, the mechanical strength of solder joints and samples having the same transversal section as resistor 1206 case type made using the same LTLF alloys into Vapour Phase Soldering (VPS) process characterized by different cooling rates (slow and rapid) and two types of test PCBs pads finish, were benchmarked at room temperature. The presented work extends the theoretical studies and experiments upon heat transfer in VPSP in order to optimize the technology for soldering process (SP) of automotive electronic modules and could be extended for home and modern agriculture appliances industry. The shear forces (SF) values of the LTLF alloy samples having the same transversal section as resistor 1206 case type will be considered as references values of a database useful in the new solder alloy creation processes and their qualification for automotive electronics domain.

  9. Fundamentals of lead-free solder interconnect technology from microstructures to reliability

    CERN Document Server

    Lee, Tae-Kyu; Kim, Choong-Un; Ma, Hongtao

    2015-01-01

    This unique book provides an up-to-date overview of the fundamental concepts behind lead-free solder and interconnection technology. Readers will find a description of the rapidly increasing presence of electronic systems in all aspects of modern life as well as the increasing need for predictable reliability in electronic systems. The physical and mechanical properties of lead-free solders are examined in detail, and building on fundamental science, the mechanisms responsible for damage and failure evolution, which affect reliability of lead-free solder joints are identified based on microstructure evolution.  The continuing miniaturization of electronic systems will increase the demand on the performance of solder joints, which will require new alloy and processing strategies as well as interconnection design strategies. This book provides a foundation on which improved performance and new design approaches can be based.  In summary, this book:  Provides an up-to-date overview on lead-free soldering tech...

  10. Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components

    Science.gov (United States)

    Ripley, Edward B.; Hallman, Russell L.

    2015-11-10

    Disclosed are methods and systems for controlling of the microstructures of a soldered, brazed, welded, plated, cast, or vapor deposited manufactured component. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. Such systems and processes may be used with components consisting of only materials that are conventionally characterized as be uninfluenced by magnetic forces.

  11. A Feasibility Study of Lead Free Solders for Level 1 Packaging Applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    An attempt has been made to determine the lead free ternary combinations that satisfied the solidification requirement for a solder used in level 1 packaging applications, using the CALPHAD approach. The segregation profiles of the promising candidates were analyzed after scrutinizing the equilib......An attempt has been made to determine the lead free ternary combinations that satisfied the solidification requirement for a solder used in level 1 packaging applications, using the CALPHAD approach. The segregation profiles of the promising candidates were analyzed after scrutinizing...

  12. Au-Ge based Candidate Alloys for High-Temperature Lead-Free Solder Alternatives

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure and microhard......Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure...... was primarily strengthened by the refined (Ge) dispersed phase. The distribution of phases played a relatively more crucial role in determining the ductility of the bulk solder alloy. In the present work it was found that among the low melting point metals, the addition of Sb to the Au-Ge eutectic would...

  13. Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

    Directory of Open Access Journals (Sweden)

    Lei Sun

    2015-01-01

    Full Text Available SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth and nanoparticles to the SnAgCu solders. In this paper, the work of SnAgCu lead-free solders containing alloying elements and nanoparticles was reviewed, and the effects of alloying elements and nanoparticles on the melting temperature, wettability, mechanical properties, hardness properties, microstructures, intermetallic compounds, and whiskers were discussed.

  14. Mechanical performances of lead-free solder joint connections with applications in the aerospace domain

    Directory of Open Access Journals (Sweden)

    Georgiana PADURARU

    2016-03-01

    Full Text Available The paper presents some theoretical and experimental aspects regarding the tribological performances of lead-free solder joint connections, with application in the aerospace domain. In order to highlight the mechanical and tribological properties of solder joint in correlation with different pad finishes, there were made some mechanical determinations using a dedicated Share Test System. The theoretical model highlights the link between the experimental results and the influence of gravitational acceleration on the mechanical and functional integrity of the electronic assemblies that works in vibration environment. The paper novelty is provided by the interdisciplinary experiment that offers results that can be used in the mechanical, tribological, electronical and aerospace domains.

  15. Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

    OpenAIRE

    Sun, Lei; Zhang, Liang

    2015-01-01

    SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth) and nanoparti...

  16. The thermodynamic database COST MP0602 for materials for high-temperature lead-free soldering

    Czech Academy of Sciences Publication Activity Database

    Kroupa, Aleš; Dinsdale, A.; Watson, A.; Vřešťál, J.; Zemanová, Adéla; Brož, P.

    2012-01-01

    Roč. 48, č. 3 (2012), s. 339-346 ISSN 1450-5339 R&D Projects: GA MŠk LD11024 Institutional support: RVO:68081723 Keywords : CALPHAD method * lead-free solders * thermodynamic database Subject RIV: BJ - Thermodynamics Impact factor: 1.435, year: 2012

  17. Electrochemical migration of lead-free solder alloys in Na2SO4 environment

    DEFF Research Database (Denmark)

    Medgyes, Balint; Ádám, Sándor; Tar, Lajos

    2017-01-01

    The effect of sulphate ion concentration on electrochemical migration of lead-free solder alloys was investigated with the use of water drop tests, by applying an in-situ optical and electrical inspection system. According to the Mean-Time-To-Failure (MTTF) values it was found that in the case of...

  18. Fluxless flip-chip bonding using a lead-free solder bumping technique

    Science.gov (United States)

    Hansen, K.; Kousar, S.; Pitzl, D.; Arab, S.

    2017-09-01

    With the LHC exceeding the nominal instantaneous luminosity, the current barrel pixel detector (BPIX) of the CMS experiment at CERN will reach its performance limits and undergo significant radiation damage. In order to improve detector performance in high luminosity conditions, the entire BPIX is replaced with an upgraded version containing an additional detection layer. Half of the modules comprising this additional layer are produced at DESY using fluxless and lead-free bumping and bonding techniques. Sequential solder-jetting technique is utilized to wet 40-μm SAC305 solder spheres on the silicon-sensor pads with electroless Ni, Pd and immersion Au (ENEPIG) under-bump metallization (UBM). The bumped sensors are flip-chip assembled with readout chips (ROCs) and then reflowed using a flux-less bonding facility. The challenges for jetting low solder volume have been analyzed and will be presented in this paper. An average speed of 3.4 balls per second is obtained to jet about 67 thousand solder balls on a single chip. On average, 7 modules have been produced per week. The bump-bond quality is evaluated in terms of electrical and mechanical properties. The peak-bump resistance is about 17.5 mΩ. The cross-section study revealed different types of intermetallic compounds (IMC) as a result of interfacial reactions between UBM and solder material. The effect of crystalline phases on the mechanical properties of the joint is discussed. The mean shear strength per bump after the final module reflow is about 16 cN. The results and sources of yield loss of module production are reported. The achieved yield is 95%.

  19. SMT soldering handbook

    National Research Council Canada - National Science Library

    Strauss, Rudolf

    1998-01-01

    ... 3.2.1 Constituents, melting behaviour and mechanical properties 3.2.2 Composition of solders for use in electronics 3.2.3 Lead-free solders 3.2.4 Solder impurities The soldered joint 3.3.1 Solde...

  20. Effect of surface oxide on the melting behavior of lead-free solder nanowires and nanorods

    International Nuclear Information System (INIS)

    Gao Fan; Rajathurai, Karunaharan; Cui, Qingzhou; Zhou, Guangwen; NkengforAcha, Irene; Gu Zhiyong

    2012-01-01

    Lead-free nanosolders have shown promise in nanowire and nanoelectronics assembly. Among various important parameters, melting is the most fundamental property affecting the assembly process. Here we report that the melting behavior of tin and tin/silver nanowires and nanorods can be significantly affected by the surface oxide of nanosolders. By controlling the nanosolder reflow atmosphere using a flux, the surface oxide of the nanowires/nanorods can be effectively removed and complete nanosolder melting can be achieved. The complete melting of the nanosolders leads to the formation of nanoscale to microscale spherical solder balls, followed by Ostwald ripening phenomenon. The contact angle of the microscale solder balls formed on Si substrate was measured by direct electron microscopic imaging. These results provide new insights into micro- and nanoscale phase transition and liquid droplet coalescence from nanowires/nanorods to spheroids, and are relevant to nanoscale assembly and smaller ball grid array formation.

  1. Investigation Of The Effects Of Reflow Profile Parameters On Lead-free Solder Bump Volumes And Joint Integrity

    Science.gov (United States)

    Amalu, E. H.; Lui, Y. T.; Ekere, N. N.; Bhatti, R. S.; Takyi, G.

    2011-01-01

    The electronics manufacturing industry was quick to adopt and use the Surface Mount Technology (SMT) assembly technique on realization of its huge potentials in achieving smaller, lighter and low cost product implementations. Increasing global customer demand for miniaturized electronic products is a key driver in the design, development and wide application of high-density area array package format. Electronic components and their associated solder joints have reduced in size as the miniaturization trend in packaging continues to be challenged by printing through very small stencil apertures required for fine pitch flip-chip applications. At very narrow aperture sizes, solder paste rheology becomes crucial for consistent paste withdrawal. The deposition of consistent volume of solder from pad-to-pad is fundamental to minimizing surface mount assembly defects. This study investigates the relationship between volume of solder paste deposit (VSPD) and the volume of solder bump formed (VSBF) after reflow, and the effect of reflow profile parameters on lead-free solder bump formation and the associated solder joint integrity. The study uses a fractional factorial design (FFD) of 24-1 Ramp-Soak-Spike reflow profile, with all main effects and two-way interactions estimable to determine the optimal factorial combination. The results from the study show that the percentage change in the VSPD depends on the combination of the process parameters and reliability issues could become critical as the size of solder joints soldered on the same board assembly vary greatly. Mathematical models describe the relationships among VSPD, VSBF and theoretical volume of solder paste. Some factors have main effects across the volumes and a number of interactions exist among them. These results would be useful for R&D personnel in designing and implementing newer applications with finer-pitch interconnect.

  2. Microstructurally Adaptive Constitutive Relations and Reliability Assessment Protocols for Lead Free Solder

    Science.gov (United States)

    2015-05-05

    under bump metallurgy and solder joint geometry on Sn grain morphology in Pb free solder joints were examined. SnAgCu solder joints were examined for...free solder interconnects”, Sci. Technol. Weld . Join. 13, 732 (2008). [3.25] Terashima, S., Takahama, K., Nozaki, M., and Tanaka, M. Recrystallization

  3. Effect of Multiple Reflow Cycles and Al2O3 Nanoparticles Reinforcement on Performance of SAC305 Lead-Free Solder Alloy

    Science.gov (United States)

    Tikale, Sanjay; Prabhu, K. Narayan

    2018-05-01

    The effect of Al2O3 nanoparticles reinforcement on melting behavior, microstructure evolution at the interface and joint shear strength of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder alloy subjected to multiple reflow cycles was investigated. The reinforced SAC305 solder alloy compositions were prepared by adding Al2O3 nanoparticles in different weight fractions (0.05, 0.1, 0.3 and 0.5 wt.%) through mechanical dispersion. Cu/solder/Cu micro-lap-shear solder joint specimens were used to assess the shear strength of the solder joint. Differential scanning calorimetry was used to investigate the melting behavior of SAC305 solder nanocomposites. The solder joint interfacial microstructure was studied using scanning electron microscopy. The results showed that the increase in melting temperature (T L) and melting temperature range of the SAC305 solder alloy by addition of Al2O3 nanoparticles were not significant. In comparison with unreinforced SAC305 solder alloy, the reinforcement of 0.05-0.5 wt.% of Al2O3 nanoparticles improved the solder wettability. The addition of nanoparticles in minor quantity effectively suppressed the Cu6Sn5 IMC growth, improved the solder joint shear strength and ductility under multiple reflow cycles. However, the improvement in solder properties was less pronounced on increasing the nanoparticle content above 0.1 wt.% of the solder alloy.

  4. Life cycle assessment (LCA of lead-free solders from the environmental protection aspect

    Directory of Open Access Journals (Sweden)

    Mitovski Aleksandra M.

    2009-01-01

    Full Text Available Life-cycle assessment (LCA presents a relatively new approach, which allows comprehensive environmental consequences analysis of a product system over its entire life. This analysis is increasingly being used in the industry, as a tool for investigation of the influence of the product system on the environment, and serves as a protection and prevention tool in ecological management. This method is used to predict possible influences of a certain material to the environment through different development stages of the material. In LCA, the product systems are evaluated on a functionally equivalent basis, which, in this case, was 1000 cubic centimeters of an alloy. Two of the LCA phases, life-cycle inventory (LCA and life-cycle impact assessment (LCIA, are needed to calculate the environmental impacts. Methodology of LCIA applied in this analysis aligns every input and output influence into 16 different categories, divided in two subcategories. The life-cycle assessment reaserch review of the leadfree solders Sn-Cu, SAC (Sn-Ag-Cu, BSA (Bi-Sb-Ag and SABC (Sn-Ag-Bi-Cu respectively, is given in this paper, from the environmental protection aspect starting from production, through application process and finally, reclamation at the end-of-life, i.e. recycling. There are several opportunities for reducing the overall environmental and human health impacts of solder used in electronics manufacturing based on the results of the LCA, such as: using secondary metals reclaimed through post-industrial recycling; power consumption reducing by replacing older, less efficient reflow assembly equipment, or by optimizing the current equipment to perform at the elevated temperatures required for lead-free soldering, etc. The LCA analysis was done comparatively in relation to widely used Sn-Pb solder material. Additionally, the impact factors of material consumption, energy use, water and air reserves, human health and ecotoxicity have been ALSO considered including

  5. Effect of trace elements on the interface reactions between two lead-free solders and copper or nickel substrates

    Directory of Open Access Journals (Sweden)

    Soares D.

    2007-01-01

    Full Text Available Traditional Sn-Pb solder alloys are being replaced, because of environmental and health concerns about lead toxicity. Among some alternative alloy systems, the Sn-Zn and Sn-Cu base alloy systems have been studied and reveal promising properties. The reliability of a solder joint is affected by the solder/substrate interaction and the nature of the layers formed at the interface. The solder/substrate reactions, for Sn-Zn and Sn-Cu base solder alloys, were evaluated in what concerns the morphology and chemical composition of the interface layers. The effect of the addition of P, at low levels, on the chemical composition of the layers present at the interface was studied. The phases formed at the interface between the Cu or Ni substrate and a molten lead-free solder at 250ºC, were studied for different stage times and alloy compositions. The melting temperatures, of the studied alloys, were determined by Differential Scanning Calorimetry (DSC. Identification of equilibrium phases formed at the interface layer, and the evaluation of their chemical composition were performed by Scanning Electron Microscopy (SEM/EDS. Different interface characteristics were obtained, namely for the alloys containing Zn. The obtained IML layer thickness was compared, for both types of alloy systems.

  6. Finite Element-Assisted Assessment of the Thermo-cyclic Characteristics of Leads Soldered with SnAgCu(+Bi,In) Alloys

    Science.gov (United States)

    Lis, Adrian; Nakanishi, Kohei; Matsuda, Tomoki; Sano, Tomokazu; Minagawa, Madoka; Okamoto, Masahide; Hirose, Akio

    2017-07-01

    Solder joints between leads and printed circuit boards in thin small outline packages were produced with conventional Sn1.0Ag0.7Cu (SAC107) and Sn3.0Ag0.7Cu (SAC305) solders as well as various solder alloys with gradually increasing amounts of Bi (up to 3.0 wt.%) and In (up to 1.0 wt.%) within the SAC107 base solder. The reliability of soldered leads in temperature cycle (TC) tests improved most with solder alloys containing both Bi (1.6 wt.%) and In (0.5 wt.%). Microindentation and electron probe microanalysis mappings revealed that the effect originates from a combination of solution and precipitation strengthening of the initial SAC alloy. The distribution of inelastic strain accumulation (ISA), as a measure for degradation, was determined in the solder joints by finite element calculations. It was shown that defects in the solder proximal to the lead (60-75 μm), which was underpinned by similar cracking characteristics along the lead-solder interface. The ISA was confirmed to be lower in SAC+Bi/In alloys owing to their enhanced elasto-plastic properties. Moreover, the addition of a thin Cu coating on the leads could improve the joint reliability, as suggested by the calculation of the ISA and the acceleration factor.

  7. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haiyan [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Peng, Jianke [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Wang, Xincheng [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Xie, Yan [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2016-04-15

    Graphical abstract: - Highlights: • The wetting angle of lead free solder on Cu was reduced by surface microstructure. • The wetting form of Sn-Ag-Cu solder on Cu was “non-composite surface”. • The experimental results had a sound fit with the theoretical calculation. - Abstract: In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  8. Effects of Fe2NiO4 nanoparticles addition into lead free Sn–3.0Ag–0.5Cu solder pastes on microstructure and mechanical properties after reflow soldering process

    International Nuclear Information System (INIS)

    Chellvarajoo, Srivalli; Abdullah, M.Z.; Samsudin, Z.

    2015-01-01

    Highlights: • Fe 2 NiO 4 nanoparticles added into SAC 305 by mechanical mixing to form nanocomposite solder paste. • Nanoparticles in the composite solder travels with flux to the outermost surface after reflow. • The intermetallics compound reduced with the addition of nanoparticles into solder paste. • The hardness increased with the addition of limited percentage of nanoparticles into SAC 305. - Abstract: This study investigates the effects of the addition of Fe 2 NiO 4 nanoparticles into a SAC-305 lead-free solder paste. Iron, nickel, and oxide nano-elements were mixed with Pb-free solder alloying elements to produce a new form of nanocomposite solder paste, which can be a promising material in electronic packaging. The SAC-305 was mechanically added with 0.5, 1.5, and 2.5 wt.% of Fe 2 NiO 4 nanoparticles. The migration of nanoparticles in the nanocomposite solder paste to the outermost surface was clarified using the copper ‘sandwich’ method, which was performed after the reflow soldering process. Varying amounts of nanoparticles in the SAC-305 affected the IMC thickness and mechanical properties of the nanocomposite solder paste. The IMC thickness was reduced by 29.15%, 42.37%, and 59.00% after adding 0.5, 1.5, and 2.5 wt.% of Fe 2 NiO 4 nanoparticles in the SAC-305, respectively. However, via nanoindentation method, the hardness of the nanocomposite solder was improved by 44.07% and 56.82% after adding 0.5 and 1.5 wt.% of Fe 2 NiO 4 nanoparticles, respectively. If the addition of Fe 2 NiO 4 nanoparticle exceeded 1.5 wt.%, the hardness increased infinitely

  9. The effect of micro alloying on the microstructure evolution of Sn-Ag-Cu lead-free solder

    Science.gov (United States)

    Werden, Jesse

    The microelectronics industry is required to obtain alternative Pb-free soldering materials due to legal, environmental, and technological factors. As a joining material, solder provides an electrical and mechanical support in electronic assemblies and therefore, the properties of the solder are crucial to the durability and reliability of the solder joint and the function of the electronic device. One major concern with new Pb-free alternatives is that the microstructure is prone to microstructural coarsening over time which leads to inconsistent properties over the device's lifetime. Power aging the solder is a common method of stabilizing the microstructure for Pb-based alloys, however, it is unclear if this will be an appropriate solution to the microstructural coarsening of Pb-free solders. The goal of this work is to develop a better understanding of the coarsening process in new solder alloys and to suggest methods of stabilizing the solder microstructure. Microalloying is one potential solution to the microstructural coarsening problem. This experiment consists of a microstructural coarsening study of SAC305 in which each sample has been alloyed with one of three different solutes, directionally solidified at 100microm/s, and then aged at three different temperatures over a total period of 20 days. There are several important conclusions from this experiment. First, the coarsening kinetics of the intermetallics in the ternary eutectic follow the Ostwald ripening model where r3 in proprotional to t for each alloying constituent. Second, the activation energy for coarsening was found to be 68.1+/-10.3 kJ/mol for the SAC305 samples, Zn had the most significant increase in the activation energy increasing it to 88.8+/-34.9 kJ/mol for the SAC+Zn samples, Mn also increased the activation energy to 83.2+/-20.8 kJ/mol for the SAC+Mn samples, and Sb decreased the activation energy to 48.0+/-3.59 kJ/mol for the SAC+Sb samples. Finally, it was found that the

  10. Lead plating of the low beta resonator

    International Nuclear Information System (INIS)

    Brennan, J.M.; Corcoran, D.; Coughlin, R.; Goliak, T.; Hodgkins, D.; James, P.; Seamster, A.G.; Secora, J.H.

    1984-01-01

    Plating operations were performed at the lead plating facility at SUNY, Stony Brook. Initial procedures were based on the previous experience of prototype development by Ben-Zvi and Brennan. Several attempts were made to produce satisfactory results, however the lead surfaces were consistently stained and lacked the bright metallic finish routinely achieved with the split loop resonator at SUNY. The development of a new set of procedures was initiated, aided by reports of plating success from Ben-Zvi. Controlled tests were conducted which suggested several changes in the plating parameters. Based on these results and suggestions from the staff at SUNY a new process was defined which was successful in producing the smooth reflective metallic surface known to be necessary forla optimum resonator performance. Following a successful repair of the the crack, the prototype was plated and chemically polished with the new techniques. The resultant surface was highly reflective and free of stains and particulates. The subsequent prototype cold test was successful

  11. Corrosion Reliability of Lead-free Solder Systems Used in Electronics

    DEFF Research Database (Denmark)

    Li, Feng; Verdingovas, Vadimas; Medgyes, Balint

    2017-01-01

    humidity/temperature cycling tests on soldered surface insulation resistance (SIR) comb pattern. Complimentary microstructural and phase analysis of solder alloys has been carried out using the scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods...

  12. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part II. Intermetallic Coarsening Behavior of Rapidly Solidified Solders After Multiple Reflows

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Controlling the size, dispersion, and stability of intermetallic compounds in lead-free solder alloys is vital to creating reliable solder joints regardless of how many times the solder joints are melted and resolidified (reflowed) during circuit board assembly. In this article, the coarsening behavior of Cu x Al y and Cu6Sn5 in two Sn-Cu-Al alloys, a Sn-2.59Cu-0.43Al at. pct alloy produced via drip atomization and a Sn-5.39Cu-1.69Al at. pct alloy produced via melt spinning at a 5-m/s wheel speed, was characterized after multiple (1-5) reflow cycles via differential scanning calorimetry between the temperatures of 293 K and 523 K (20 °C and 250 °C). Little-to-no coarsening of the Cu x Al y particles was observed for either composition; however, clustering of Cu x Al y particles was observed. For Cu6Sn5 particle growth, a bimodal size distribution was observed for the drip atomized alloy, with large, faceted growth of Cu6Sn5 observed, while in the melt spun alloy, Cu6Sn5 particles displayed no significant increase in the average particle size, with irregularly shaped, nonfaceted Cu6Sn5 particles observed after reflow, which is consistent with shapes observed in the as-solidified alloys. The link between original alloy composition, reflow undercooling, and subsequent intermetallic coarsening behavior was discussed by using calculated solidification paths. The reflowed microstructures suggested that the heteroepitaxial relationship previously observed between the Cu x Al y and the Cu6Sn5 was maintained for both alloys.

  13. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Marcelino; Costa, Thiago [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Rocha, Otávio [Federal Institute of Education, Science and Technology of Pará — IFPA, 66093-020 Belém, PA (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos — UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé, E-mail: cheung@fem.unicamp.br [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil)

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  14. Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis

    International Nuclear Information System (INIS)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-01-01

    Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme. -- Highlights: ► We model the life cycle flows for solder-containing metals in Japan. ► The Japanese shift to lead-free solders progresses rapidly for a decade. ► Substitution for lead in solders slows down during the late life cycle stages. ► The deceleration of substitution precludes a reduction in lead emissions to air.

  15. Effects of voids on thermal-mechanical reliability of lead-free solder joints

    Directory of Open Access Journals (Sweden)

    Benabou Lahouari

    2014-06-01

    Full Text Available Reliability of electronic packages has become a major issue, particularly in systems used in electrical or hybrid cars where severe operating conditions must be met. Many studies have shown that solder interconnects are critical elements since many failure mechanisms originate from their typical response under thermal cycles. In this study, effects of voids in solder interconnects on the electronic assembly lifetime are estimated based on finite element simulations.

  16. Behavior of Sn-0.7Cu-xZn lead free solder on physical properties and micro structure

    Science.gov (United States)

    Siahaan, Erwin

    2017-09-01

    The issues to substitute Tin-Lead Solders is concerning the health and environmental hazards that is caused by lead, and also legislative actions around the world regarding lead toxicity, which has prompted the research community to attempt to replace solder alloys for the traditional Sn-Pb alloys lead which has been used by industrial worker throughout history because it is easily extracted and refined at a relatively low energy cost and also has a range of useful properties. Traditional industry lead has been used in soldering materials for electronic applications because it has low melting point and a soft, malleable nature, when combined with tin at the eutectic composition which causes the alloy to flow easily in the liquid state and solidifies over a very small range of temperature. One of the potential candidate to replace tin-lead solder is Sn-Cu-Zn eutectic alloy as it has a lower melting temperature. Consequently, it is of interest to determine what reactions can occur in ternary systems derived from the Sn-Cu-Zn eutectic. One such system is Sn-0.7Cu-xZn. The specimen was elaborated on physical properties. The chemical content was analyzed by using Shimadzu XRD and melting point was analyzed by using Differential Scanning Calorimeter ( DSC ). The results has shown that the highest addition of Zinc content (15%Zn) will decrease the melting temperatur to 189°C compared to Sn-Pb at 183°C Increasing the amount of Zn on Sn0.7Cu-xZn alloys will decrease Cu3Sn intermetallic coumpound.

  17. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    International Nuclear Information System (INIS)

    Sujan, G.K.; Haseeb, A.S.M.A.; Afifi, A.B.M.

    2014-01-01

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu 6 Sn 5 from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping of flux

  18. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sujan, G.K., E-mail: sgkumer@gmail.com; Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Afifi, A.B.M., E-mail: amalina@um.edu.my

    2014-11-15

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu{sub 6}Sn{sub 5} from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping

  19. Enhanced interfacial thermal transport in pnictogen tellurides metallized with a lead-free solder alloy

    Energy Technology Data Exchange (ETDEWEB)

    Devender,; Ramanath, Ganpati, E-mail: Ramanath@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lofgreen, Kelly; Devasenathipathy, Shankar; Swan, Johanna; Mahajan, Ravi [Intel Corporation, Assembly Test and Technology Development, Chandler, Arizona 85226 (United States); Borca-Tasciuc, Theodorian [Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-11-15

    Controlling thermal transport across metal–thermoelectric interfaces is essential for realizing high efficiency solid-state refrigeration and waste-heat harvesting power generation devices. Here, the authors report that pnictogen chalcogenides metallized with bilayers of Sn{sub 96.5}Ag{sub 3}Cu{sub 0.5} solder and Ni barrier exhibit tenfold higher interfacial thermal conductance Γ{sub c} than that obtained with In/Ni bilayer metallization. X-ray diffraction and x-ray spectroscopy indicate that reduced interdiffusion and diminution of interfacial SnTe formation due to Ni layer correlates with the higher Γ{sub c}. Finite element modeling of thermoelectric coolers metallized with Sn{sub 96.5}Ag{sub 3}Cu{sub 0.5}/Ni bilayers presages a temperature drop ΔT ∼ 22 K that is 40% higher than that obtained with In/Ni metallization. Our results underscore the importance of controlling chemical intermixing at solder–metal–thermoelectric interfaces to increase the effective figure of merit, and hence, the thermoelectric cooling efficiency. These findings should facilitate the design and development of lead-free metallization for pnictogen chalcogenide-based thermoelectrics.

  20. Available: lead plate from COMPASS experiment

    CERN Multimedia

    The COMPASS collaboration

    2014-01-01

    The COMPASS collaboration would like to offer the possibility to take over a large and thick lead plate, since it is not required anymore in the spectrometer.   It has the following dimensions: thickness 100 mm, width 4.4 m and height 2.0 m, with a square hole in the middle with dimensions of 40 cm x 40 cm. The measured weight including the metal frame it is housed in is 10,180 kg. The CERN stores reference is 44.13.30.100.9. Please contact Erwin Bielert (erwin.bielert@cern.ch or 160539) for further information and details.

  1. Corrosion Behaviour of Sn-based Lead-Free Solders in Acidic Solution

    Science.gov (United States)

    Nordarina, J.; Mohd, H. Z.; Ahmad, A. M.; Muhammad, F. M. N.

    2018-03-01

    The corrosion properties of Sn-9(5Al-Zn), Sn-Cu and SAC305 were studied via potentiodynamic polarization method in an acidic solution of 1 M hydrochloric acid (HCl). Sn-9(5Al-Zn) produced different polarization profile compared with Sn-Cu and SAC305. The morphological analysis showed that small, deep grooves shaped of corrosion product formed on top of Sn-9(5Al-Zn) solder while two distinctive structures of closely packed and loosely packed corrosion product formed on top of Sn-Cu and SAC305 solder alloys. Phase analysis revealed the formations of various corrosion products such as SnO and SnO2 mainly dominant on surface of solder alloys after potentiodynamic polarization in 1 M hydrochloric acid (HCl).

  2. Measurement of erosion of stainless steel by molten lead-free solder using micro-focus x-ray CT system

    International Nuclear Information System (INIS)

    Nishikawa, Hiroshi; Takemoto, Tadashi; Kang, Songai

    2009-01-01

    The severe erosion damage, which is caused by a molten lead-free solder, of wave solder equipment made into stainless steel has been encountered in operation. Then, the higher maintenance frequency and reduced life time of wave solder machine component is a serious issue in a manufacturing process. In this study, the evaluation method of erosion of stainless steel by molten lead-free solders was investigated using micro-focus X-ray systems for fluoroscopic and computed tomography (CT). As a result, it was found that the fluoroscopic image could truly reconstruct the cross-shape of the stainless steel sample after immersion test without destruction. In the case of X-ray systems for fluoroscopic and CT used in this study, three-dimensional data can be obtained. Therefore, it was possible to easily check the whole picture of the test sample after immersion test and to decide the maximum erosion depth of test sample. (author)

  3. The micro-droplet behavior of a molten lead-free solder in an inkjet printing process

    International Nuclear Information System (INIS)

    Tsai, M H; Chou, H H; Hwang, W S

    2009-01-01

    An experimental investigation on the droplet formation of molten Sn3.0 wt%Ag0.5 wt%Cu alloy by an inkjet printing process was conducted. The printing process used a piezoelectric print head with a nozzle orifice diameter of 50 µm. Micro-droplets of a molten lead-free solder were ejected at 230 °C. The print head was driven by a bipolar pulse 40 V in amplitude. The major variables for this study were two pulse times; t rise /t finalrise and t fall , as well as N 2 back-pressure in the molten solder reservoir. Under various printing conditions, extrusion of the liquid column, contraction of liquid thread and pinch-off of liquid thread at nozzle exit were observed by monitoring the dynamics of the molten solder droplet ejection process. The droplet formation was found to be insensitive to t rise and t finalrise in the range of 250–1000 µs. The behavior of droplet formation was, however, significantly affected by the transfer rate, t fall , in the range of 30–60 µs and t fall of 50 µs yielded the most desirable condition of single droplet formation. The N 2 back-pressure was also found to be critical, where a back pressure between 10 and 21 kPa could give the desirable single-droplet formation condition

  4. Characteristics of solder joints under fatigue loads using piezomechanical actuation

    Science.gov (United States)

    Shim, Dong-Jin; Spearing, S. Mark

    2003-07-01

    Crack initiation and growth characteristics of solder joints under fatigue loads are investigated using piezomechanical actuation. Cracks in solder joints, which can cause failure in microelectronics components, are induced via piezoelectricity in piezo-ceramic bonded joints. Lead-zirconate-titanate ceramic plates and eutectic Sn-Pb solder bonded in a double-lap shear configuration are used in the investigation. Electric field across each piezo-ceramic plate is applied such that shear stresses/strains are induced in the solder joints. The experiments show that cracks initiate in the solder joints around defects such as voids and grow in length until they coalesce with other cracks from adjacent voids. These observations are compared with the similar thermal cycling tests from the literature to show feasibility and validity of the current method in investigating the fatigue characteristics of solder joints. In some specimens, cracks in the piezo-ceramic plates are observed, and failure in the specimens generally occurred due to piezo-ceramic plate fracture. The issues encountered in implementing this methodology such as low actuation and high processing temperatures are further discussed.

  5. Effect of cooling rate during solidification of Sn-9Zn lead-free solder alloy on its microstructure, tensile strength and ductile-brittle transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, K.N., E-mail: prabhukn_2002@yahoo.co.in [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India); Deshapande, Parashuram; Satyanarayan [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Effect of cooling rate on tensile and impact properties of Sn-9Zn alloy was assessed. Black-Right-Pointing-Pointer Both DBTT and UTS of the solder alloy increased with increase in cooling rate. Black-Right-Pointing-Pointer An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile-brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn-9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 Degree-Sign C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the

  6. Effect of cooling rate during solidification of Sn–9Zn lead-free solder alloy on its microstructure, tensile strength and ductile–brittle transition temperature

    International Nuclear Information System (INIS)

    Prabhu, K.N.; Deshapande, Parashuram; Satyanarayan

    2012-01-01

    Highlights: ► Effect of cooling rate on tensile and impact properties of Sn–9Zn alloy was assessed. ► Both DBTT and UTS of the solder alloy increased with increase in cooling rate. ► An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile–brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn–9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 °C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the DBTT.

  7. Soldering handbook

    CERN Document Server

    Vianco, Paul T

    1999-01-01

    Contains information related to soldering processes, and solder joint performance and reliability. Covers soldering fundamentals, technology, materials, substrate materials, fluxes, pastes, assembly processes, inspection, and environment. Covers today's advanced joining applications and emphasizes new materials, including higher strength alloys; predictive performance; computer modeling; advanced inspection techniques; new processing concepts, including laser heating; and the resurgence in ultrasonic soldering.

  8. Development of Au-Ge based candidate alloys as an alternative to high-lead content solders

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2010-01-01

    Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The changes in microstructure and microhardness associated with the addition of low melting point metals namely In, Sb and Sn to the Au......-Ge-In and Au-Ge-Sn combinations was determined to be the classic solid solution strengthening. The Au-Ge-Sb combination was primarily strengthened by the refined (Ge) dispersed phase. The aging temperature had a significant influence on the microhardness in the case of the Au-Ge-Sn candidate alloy...

  9. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chih-Yao [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hon, Min-Hsiung [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 80728, Taiwan (China); Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China)

    2014-01-05

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag{sub 3}Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn{sub 3}. No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging.

  10. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    International Nuclear Information System (INIS)

    Liu, Chih-Yao; Hon, Min-Hsiung; Wang, Moo-Chin; Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long

    2014-01-01

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag 3 Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn 3 . No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging

  11. Investigation of wall-slip effect on lead-free solder paste and ...

    Indian Academy of Sciences (India)

    In the study, three different plate materials were utilised namely; stainless steel plate, aluminium grooved ..... the stainless steel plate and the highest adhesion is to the glass plate. The author also ... Part B 20(4): 416–423. Riedlin M H A 1998 ...

  12. Elevated-Temperature Mechanical Properties of Lead-Free Sn-0.7Cu- xSiC Nanocomposite Solders

    Science.gov (United States)

    Mohammadi, A.; Mahmudi, R.

    2018-02-01

    Mechanical properties of Sn-0.7 wt.%Cu lead-free solder alloy reinforced with 0 vol.%, 1 vol.%, 2 vol.%, and 3 vol.% 100-nm SiC particles have been assessed using the shear punch testing technique in the temperature range from 25°C to 125°C. The composite materials were fabricated by the powder metallurgy route by blending, compacting, sintering, and finally extrusion. The 2 vol.% SiC-containing composite showed superior mechanical properties. In all conditions, the shear strength was adversely affected by increasing test temperature, and the 2 vol.% SiC-containing composite showed superior mechanical properties. Depending on the test temperature, the shear yield stress and ultimate shear strength increased, respectively, by 3 MPa to 4 MPa and 4 MPa to 5.5 MPa, in the composite materials. The strength enhancement was mostly attributed to the Orowan particle strengthening mechanism due to the SiC nanoparticles, and to a lesser extent to the coefficient of thermal expansion mismatch between the particles and matrix in the composite solder. A modified shear lag model was used to predict the total strengthening achieved by particle addition, based on the contribution of each of the above mechanisms.

  13. Microstructure and adhesion strength of Sn-9Zn-xAg lead-free solders wetted on Cu substrate

    International Nuclear Information System (INIS)

    Chang, T.-C.; Chou, S.-M.; Hon, M.-H.; Wang, M.-C.

    2006-01-01

    The microstructure and adhesion strength of the Sn-9Zn-xAg lead-free solders wetted on Cu substrates have been investigated by differential scanning calorimetry, optical microscopy, scanning electron microscopy, energy dispersive spectrometry and pull-off testing. The liquidus temperatures of the Sn-9Zn-xAg solder alloys are 222.1, 226.7, 231.4 and 232.9 deg. C for x = 2.5, 3.5, 5.0 and 7.5 wt%, respectively. A flat interface can be obtained as wetted at 350 deg. C at a rate of 11.8 mm/s. The adhesion strength of the Sn-9Zn-xAg/Cu interfaces decreases from 23.09 ± 0.31 to 12.32 ± 1.40 MPa with increasing Ag content from 2.5 to 7.5 wt% at 400 deg. C. After heat treatment at 150 deg. C, the adhesion strength of the Sn-9Zn-xAg/Cu interface decreases with increasing aging time

  14. Methodology for Analyzing Strain States During In-Situ Thermomechanical Cycling in Individual Lead Free Solder Joints Using Synchrotron Radiation

    International Nuclear Information System (INIS)

    Zhou, Bite; Bieler, Thomas R.; Lee, Tae-Kyu; Liu, Kuo-Chuan

    2009-01-01

    To examine how a lead-free solder joint deforms in a thermal cycling environment, both the elastic and plastic stress and strain behavior must be understood. Methods to identify evolution of the internal strain (stress) state during thermal cycling are described. A slice of a package containing a single row of solder joints was thermally cycled from 0 C to 100 C with a period of about 1 h with concurrent acquisition of transmission Laue patterns using synchrotron radiation. These results indicated that most joints are single crystals, with some being multicrystals with no more than a few Sn grain orientations. Laue patterns were analyzed to estimate local strains in different crystal directions at different temperatures during a thermal cycle. While the strains perpendicular to various crystal planes all vary in a similar way, the magnitude of strain varies. The specimens were subsequently given several hundred additional thermal cycles and measured again to assess changes in the crystal orientations. These results show that modest changes in crystal orientations occur during thermal cycling.

  15. Beta-Tin Grain Formation in Aluminum-Modified Lead-Free Solder Alloys

    Science.gov (United States)

    Reeve, Kathlene N.; Handwerker, Carol A.

    2018-01-01

    The limited number of independent β-Sn grain orientations that typically form during solidification of Sn-based solders and the resulting large β-Sn grain size have major effects on overall solder performance and reliability. This study analyzes whether additions of Al to Sn-Cu and Sn-Cu-Ag alloys can be used to change the grain size, morphology, and twinning structures of atomized (as-solidified) and re-melted (reflowed) β-Sn dendrites as determined using scanning electron microscopy and electron backscatter diffraction for as-solidified and reflow cycled (20-250°C, 1-5 cycles) Sn-Cu-Al and Sn-Ag-Cu-Al drip atomized spheres (260 μm diameter). The resulting microstructures were compared to as-solidified and reflow cycled Sn-Ag-Cu spheres (450 μm diameter) as well as as-solidified Sn-Ag-Cu, Sn-Cu, and Sn-Ag microstructures from the literature. Previous literature observations reporting reductions in undercooling and β-Sn grain size with Al micro-alloying additions could not be correlated to the presence of the Cu9Al4 phase or Al solute. The as-solidified spheres displayed no change in β-Sn dendrite structure or grain size when compared to non-Al-modified alloys, and the reflow cycled spheres produced high undercoolings (22-64°C), indicating a lack of potent nucleation sites. The current findings highlighted the role of Ag in the formation of the interlaced twinning structure and demonstrated that with deliberate compositional choices, formation of the alloy's β-Sn grain structure (cyclical twinning versus interlaced twinning) could be influenced, in both the as-solidified and reflow cycled states, though still not producing the fine-grain sizes and multiple orientations desired for improved thermomechanical properties.

  16. Developments of high strength Bi-containing Sn0.7Cu lead-free solder alloys prepared by directional solidification

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xiaowu, E-mail: xwhmaterials@aliyun.com [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Li, Yulong [School of Mechanical Electrical Engineering, Nanchang University, Nanchang 330031 (China); Liu, Yi [School of Materials Science and Engineering, Nanchang University, Nanchang 330031 (China); Min, Zhixian [China Electronics Technology Group Corporation No. 38 Research Institute, Hefei 230088 (China)

    2015-03-15

    Highlights: • The Sn0.7Cu–xBi solder alloys were directionally solidified. • Both spacing and diameter of fibers decreased with increasing solidification rate. • The UTS and YS first increased with increased solidification rate, then decreased. • The UTS and YS of Sn0.7Cu–xBi first increased with increased Bi content. - Abstract: Bi-containing Sn0.7Cu (SC) eutectic solder alloys were prepared and subjected to directional solidification, through which new types of fiber reinforced eutectic composites were generated. The influences of Bi addition on the microstructures and tensile properties of directionally solidified (DS) Bi-containing eutectic SC lead-free solder alloys have been investigated by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and a tensile testing machine. The experimental results showed that addition of Bi could effectively reduce both the melting temperature and undercooling of SC solder alloy. The microstructures of DS SC–xBi solder alloys were composed of Sn-rich phase (β) and Cu{sub 6}Sn{sub 5} fiber. No other intermetallic compounds (IMCs) with Bi content were observed in the solder matrix for SC solder alloys with various Bi contents. Both fiber spacing and diameter all decreased gradually with increasing growth rate and/or Bi content. Besides, the regularity of Cu{sub 6}Sn{sub 5} fibers alignment also decreased with increasing growth rate, too. The tensile strengths of the SC–xBi eutectic solder alloys varied parabolically with growth rate (R). When R was 60 μm/s, maximum tensile strengths of 43.8, 55.2 and 56.37 MPa were reached for SC, SC0.7Bi and SC1.3Bi solder alloys. A comparison of tensile strength of SC, SC0.7Bi and SC1.3Bi with the same R indicated that the tensile strength increased with increasing Bi content, which was attributed to the presence of Bi and its role in refining microstructure and solid solution strengthening.

  17. Curing pasted plates for lead/acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Napoleon, E.S.

    1987-02-15

    This paper covers various aspects of the hydroset process and final drying of battery plates in a controlled chamber. Through the use of such chambers, battery makers are obtaining finished plates of consistent quality in 48 h or less, including final drying. Added benefits include: (i) reduced free-lead in plates; (ii) reduced floor space requirements; (iii) better knitting of paste to grid; (iv) reduced inventories; (v) reduced battery rejects.

  18. Thermodynamic assessment of the Sn-Co lead-free solder system

    Science.gov (United States)

    Liu, Libin; Andersson, Cristina; Liu, Johan

    2004-09-01

    The Sn-Co-Cu eutectic alloy can be a less expensive alternative for the Sn-Ag-Cu alloy. In order to find the eutectic solder composition of the Sn-Co-Cu system, the Sn-Co binary system has been thoroughly assessed with the calculation of phase diagram (CALPHAD) method. The liquid phase, the FCC and HCP Co-rich solid solution, and the BCT Sn-rich solid solution have been described by the Redlich-Kister model. The Hillert-Jarl-Inden model has been used to describe the magnetic contributions to Gibbs energy in FCC and HCP. The CoSn2, CoSn, Co3Sn2_β, and Co3Sn2_α phases have been treated as stoichiometric phases. A series of thermodynamic parameters have been obtained. The calculated phase diagram and thermodynamic properties are in good agreement with the experimental data. The obtained thermodynamic data was used to extrapolate the ternary Sn-Co-Cu phase diagram. The composition of the Sn-rich eutectic point of the Sn-Co-Cu system was found to be 224°C, 0.4% Co, and 0.7% Cu.

  19. Electrochemical Behavior of Sn-9Zn- xTi Lead-Free Solders in Neutral 0.5M NaCl Solution

    Science.gov (United States)

    Wang, Zhenghong; Chen, Chuantong; Jiu, Jinting; Nagao, Shijo; Nogi, Masaya; Koga, Hirotaka; Zhang, Hao; Zhang, Gong; Suganuma, Katsuaki

    2018-05-01

    Electrochemical techniques were employed to study the electrochemical corrosion behavior of Sn-9Zn- xTi ( x = 0, 0.05, 0.1, 0.2 wt.%) lead-free solders in neutral 0.5M NaCl solution, aiming to figure out the effect of Ti content on the corrosion properties of Sn-9Zn, providing information for the composition design of Sn-Zn-based lead-free solders from the perspective of corrosion. EIS results reveal that Ti addition was involved in the corrosion product layer and changed electrochemical interface behavior from charge transfer control process to diffusion control process. The trace amount of Ti addition (0.05 wt.%) can refine the microstructure and improve the corrosion resistance of Sn-9Zn solder, evidenced by much lower corrosion current density ( i corr) and much higher total resistance ( R t). Excess Ti addition (over 0.1 wt.%) led to the formation of Ti-containing IMCs, which were confirmed as Sn3Ti2 and Sn5Ti6, deteriorating the corrosion resistance of Sn-9Zn- xTi solders. The main corrosion products were confirmed as Sn3O(OH)2Cl2 mixed with small amount of chlorine/oxide Sn compounds.

  20. Hybrid input-output approach to metal production and its application to the introduction of lead-free solders.

    Science.gov (United States)

    Nakamura, Shinichiro; Murakami, Shinsuke; Nakajima, Kenichi; Nagasaka, Tetsuya

    2008-05-15

    The production process of metals such as copper, lead, and zinc is characterized by mutual interconnections and interdependence, as well as by the occurrence of a large number of byproducts, which include precious or rare metals, such as gold, silver, bismuth, and indium. On the basis of the framework of waste input-output (WIO), we present a hybrid 10 model that takes full account of the mutual interdependence among the metal production processes and the interdependence between them and all the other production sectors of the economy as well. The combination of a comprehensive representation of the whole national economy and the introduction of process knowledge of metal production allows for a detailed analysis of different materials-use scenarios under the consideration of full supply chain effects. For illustration, a hypothetical case study of the introduction of lead-free solder involving the production of silver as a byproduct of copper and lead smelting processes was developed and implemented using Japanese data. To meet the increased demand for the recovery and recycling of silver resources from end-of-life products, the final destination of metal silver in terms of products and user categories was estimated, and the target components with the highest silver concentration were identified.

  1. Thermomechanical Cycling Investigation of Cu and Niti Reinforced Lead-Free Solder

    Science.gov (United States)

    2006-09-01

    hold fractured bones together during the healing process. The SMA plates have proven to perform well. The shape memory effect places the bones in...taking this a step further and developing robot prosthetic devices using SMA technology [27]. Other uses of SMA’s include hydraulic connections...glasses frames, bra underwires, fire safety valves , etc. [18]. In each case the attributes of the different alloys must be weighed to determine proper

  2. Microstructure and mechanical properties of Sn-9Zn-xAl2O3 nanoparticles (x=0–1) lead-free solder alloy: First-principles calculation and experimental research

    International Nuclear Information System (INIS)

    Xing, Wen-qing; Yu, Xin-ye; Li, Heng; Ma, Le; Zuo, Wei; Dong, Peng; Wang, Wen-xian; Ding, Min

    2016-01-01

    This paper studies microstructure and mechanical properties of Sn-9Zn-x Al 2 O 3 nanoparticles (x=0–1) lead-free solder alloy. The interface structure, interface energy and electronic properties of Al 2 O 3 /Sn9Zn interface are investigated by first-principle calculation. On the experimental part, in comparison with the plain Sn-9Zn solder, the Al 2 O 3 nanoparticles incorporated into the solder matrix can inhibit the growth of coarse dendrite Sn-Zn eutectic structure and refine grains of the composite solders during the solidification process of the alloys. Moreover, the microhardness and average tensile strength of the solders with addition of Al 2 O 3 nanoparticles increased with the increasing weight percentages of Al 2 O 3 nanoparticles. These improved mechanical properties can be attributed to the microstructure developments and the dispersed Al 2 O 3 nanoparticles.

  3. Prediction of activities of all components in the lead-free solder systems Bi-In-Sn and Bi-In-Sn-Zn

    International Nuclear Information System (INIS)

    Tao Dongping

    2008-01-01

    The activities of components of the ternary lead-free solder systems Al-Sn-Zn at 973 K, Zn-Cu-Sn at 1023 K and Bi-In-Sn at 1000 and 1050 K have been predicted by a novel molecular interaction volume model-MIVM and the results are in good agreement with experimental data. Then the activities of all components of the Bi-In-Sn at 550 K and the Bi-In-Sn-Zn quaternary system at 700 K have been further predicted and the results are reasonable and reliable. This shows that the model may be a superior alternative for describing interfacial chemical reactions between lead-free solder alloys and common base materials and for the calculation of their phase diagrams because MIVM has certain physical meaning from the viewpoint of statistical thermodynamics and requires only two infinite dilute activity coefficients for each sub-binary system

  4. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part I. Microstructural Characterization of Rapidly Solidified Solders

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Particles of Cu x Al y in Sn-Cu-Al solders have previously been shown to nucleate the Cu6Sn5 phase during solidification. In this study, the number and size of Cu6Sn5 nucleation sites were controlled through the particle size refinement of Cu x Al y via rapid solidification processing and controlled cooling in a differential scanning calorimeter. Cooling rates spanning eight orders of magnitude were used to refine the average Cu x Al y and Cu6Sn5 particle sizes down to submicron ranges. The average particle sizes, particle size distributions, and morphologies in the microstructures were analyzed as a function of alloy composition and cooling rate. Deep etching of the samples revealed the three-dimensional microstructures and illuminated the epitaxial and morphological relationships between the Cu x Al y and Cu6Sn5 phases. Transitions in the Cu6Sn5 particle morphologies from faceted rods to nonfaceted, equiaxed particles were observed as a function of both cooling rate and composition. Initial solidification cooling rates within the range of 103 to 104 °C/s were found to be optimal for realizing particle size refinement and maintaining the Cu x Al y /Cu6Sn5 nucleant relationship. In addition, little evidence of the formation or decomposition of the ternary- β phase in the solidified alloys was noted. Solidification pathways omitting the formation of the ternary- β phase agreed well with observed room temperature microstructures.

  5. Quality control in manufacture of lead boron polyethylene plate

    International Nuclear Information System (INIS)

    Wu Ying

    2008-01-01

    For the quality assurance management in the manufacture of lead boron polyethylene plate,target shall be defined and planning shall be conducted first; personnel shall be trained to improve the execution force; institutional system shall be continuously upgraded and environment protection shall be strengthened.Quality management has achieved excellent result, with qualification rate for contracts reaches 100%, to ensure successful production. (author)

  6. Active gas discharge cleaning for superconducting lead-plated resonators

    International Nuclear Information System (INIS)

    Malev, M.D.; Weisser, D.C.

    1985-06-01

    Lead-plating for superconducting RF resonators historically has been directed toward reducing grain size and eliminating spikes on the surface. Investigations were made of degassing lead-plated surfaces under RF resonant electron discharge or multipacting. The mass-spectra of the residual atmosphere showed that decomposition of hydrocarbons on the surface took place. Discolouration of the lead surface, due to the formation of a carbon layer, was easily observed. A method of cleaning surfaces by ion bombardment employing chemically active gases, was proposed and tested. An RF discharge, initiated by multipacting at pressure 10 -2 - 10 -1 torr was used. The first step, discharge treatment in a CO 2 atmosphere, assures oxidation of carbon and hydrocarbons into gaseous compounds which are removed by pumping. During the second step, discharge treatment in a hydrogen atmosphere, lead oxides are reduced to metal

  7. Evaluating print performance of Sn-Ag-Cu lead-free solder pastes used in electronics assembly process

    Science.gov (United States)

    Mallik, S.; Bauer, R.; Hübner, F.; Ekere, N. N.

    2011-01-01

    Solder paste is the most widely used interconnection material in the electronic assembly process for attaching electronic components/devices directly onto the surface of printed circuit boards, using stencil printing process. This paper evaluates the performance of three different commercially available Sn-Ag-Cu solder pastes formulated with different particle size distributions (PSD), metal content and alloy composition. A series of stencil printing tests were carried out using a specially designed stencil of 75 μm thickness and apertures of 300×300 μm2 dimension and 500 μm pitch sizes. Solder paste printing behaviors were found related to attributes such as slumping and surface tension and printing performance was correlated with metal content and PSD. The results of the study should benefit paste manufacturers and SMT assemblers to improve their products and practices.

  8. Spontaneous soldering

    International Nuclear Information System (INIS)

    Percacci, R.

    1984-01-01

    It is proposed that the soldering form of general relativity be treated as a dynamical variable. This gives rise to the possibility of treating the linear connection on (n-dimensional) spacetime and an internal O(k)-Yang-Mills field as different components of the same O(N) gauge field (N= n+k). The distinction between gravitational and Yang-Mills interactions is due to a kind of Higgs mechanism driven by the vacuum expectation value of the soldering form. (orig.)

  9. Substituição das soldas estanho-chumbo na manufatura: efeitos na saúde do trabalhador e no desempenho ambiental Substitution of tin-lead solders in manufacturing: impacts on workers' health and on the environment

    Directory of Open Access Journals (Sweden)

    Cecilia Maria Villas Bôas de Almeida

    2013-03-01

    Full Text Available As soldas à base de estanho-chumbo (63Sn/37Pb são largamente utilizadas no Brasil e no mundo. Este estudo aplica a avaliação em emergia em um fabricante de soldas brandas à base de estanho e chumbo e outros metais. O cálculo da emergia por unidade de três tipos de solda mostra que mais recursos são utilizados para produzir uma tonelada de soldas livres de chumbo do que para produzir soldas à base de estanho e chumbo. O indicador DALY (Disability Adjusted Life Years foi utilizado para comparar as emissões na atmosfera dos três tipos de produção de soldas e os resultados apontam para a adoção das soldas à base de chumbo, quando se considera todo o ciclo de vida do produto. A diferença entre os resultados obtidos por avaliações locais e globais é discutida.Tin-lead solders (Sn63-Pb37 have been widely used in Brazil and worldwide. This study evaluates the emergy in a company that manufactures soft solders based on tin, lead, and other metals. The calculation of emergy per unit of three types of solder showed that more resources are used to produce one ton of lead-free solders than those used to produce tin-lead solders. The DALY (Disability Adjusted Life Years indicator was used to assess the emissions to air of three types of solder. The results favor the use of tin-lead solders when the whole product life-cycle is evaluated. The difference between the results obtained by local and global assessments is discussed.

  10. Surface Morphology Study of Nanostructured Lead-Free Solder Alloy Sn-Ag-Cu Developed by Electrodeposition: Effect of Current Density Investigation

    Directory of Open Access Journals (Sweden)

    Sakinah Mohd Yusof

    2013-10-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Nanostructured lead-free solder Sn-Ag-Cu (SAC was developed by electrodeposition method at room temperature. Electrolite bath which comprised of the predetermined quantity of tin methane sulfonate, copper sulfate and silver sulfate were added sequentially to MSA solution. The methane sulphonic acid (MSA based ternary Sn-Ag-Cu bath was developed by using tin methane sulfonate as a source of Sn ions while the Cu+ and Ag+ ions were obtained from their respective sulfate salts. The rate of the electrodeposition was controlled by variation of current density. The addition of the buffer, comprising of sodium and ammonium acetate helped in raising the pH solution. During the experimental procedure, the pH of solution, composition of the electrolite bath, and the electrodeposition time were kept constant. The electrodeposited rate, deposit composition and microstructure were investigated as the effect of current density. The electrodeposited solder alloy was characterized for their morphology using Field Emission Scanning Electron Microscope (FESEM. In conclusion, vary of current density will play significant role in the surface morphology of nanostructured lead-free solder SAC developed. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New

  11. Effect of silver and indium addition on mechanical properties and indentation creep behavior of rapidly solidified Bi–Sn based lead-free solder alloys

    International Nuclear Information System (INIS)

    Shalaby, Rizk Mostafa

    2013-01-01

    Mechanical properties and indentation creep of the melt-spun process Bi–42 wt%Sn, Bi–40 wt%Sn–2 wt%In, Bi–40 wt%Sn–2 wt%Ag and Bi–38 wt%Sn–2 wt%In–2 wt%Ag were studied by dynamic resonance technique and Vickers indentation testing at room temperature and compared to that of the traditional Sn–37 wt%Pb eutectic alloy. The results show that the structure of Bi–42 wt%Sn alloy is characterized by the presence of rhombohedral Bi and body centered tetragonal β-Sn. The two ternary alloys exhibit additional constituent phases of intermetallic compounds SnIn 19 for Bi–40 wt%Sn–2 wt%In and ε-Ag 3 Sn for Bi–40 wt%Sn–2 wt%Ag alloys. Attention has been paid to the role of intermetallic compounds on mechanical and creep behavior. The In and Ag containing solder alloy exhibited a good combination of higher creep resistance, good mechanical properties and lower melting temperature as compared with Pb–Sn eutectic solder alloy. This was attributed to the strengthening effect of Bi as a strong solid solution element in the Sn matrix and formation of intermetallic compounds β-SnBi, ε-Ag 3 Sn and InSn 19 which act as both strengthening agent and grain refiner in the matrix of the material. Addition of In and Ag decreased the melting temperature of Bi–Sn lead-free solder from 143 °C to 133 °C which was possible mainly due to the existence of InSn 19 and Ag 3 Sn intermetallic compounds. Elastic constants, internal friction and thermal properties of Bi–Sn based alloys have been studied and analyzed.

  12. Nucleation and Growth of Cu-Al Intermetallics in Al-Modified Sn-Cu and Sn-Ag-Cu Lead-Free Solder Alloys

    Science.gov (United States)

    Reeve, Kathlene N.; Anderson, Iver E.; Handwerker, Carol A.

    2015-03-01

    Lead-free solder alloys Sn-Cu (SC) and Sn-Ag-Cu (SAC) are widely used by the microelectronics industry, but enhanced control of the microstructure is needed to improve solder performance. For such control, nucleation and stability of Cu-Al intermetallic compound (IMC) solidification catalysts were investigated by variation of the Cu (0.7-3.0 wt.%) and Al (0.0-0.4 wt.%) content of SC + Al and SAC + Al alloys, and of SAC + Al ball-grid array (BGA) solder joints. All of the Al-modified alloys produced Cu-Al IMC particles with different morphologies and phases (occasionally non-equilibrium phases). A trend of increasing Cu-Al IMC volume fraction with increasing Al content was established. Because of solidification of non-equilibrium phases in wire alloy structures, differential scanning calorimetry (DSC) experiments revealed delayed, non-equilibrium melting at high temperatures related to quenched-in Cu-Al phases; a final liquidus of 960-1200°C was recorded. During cooling from 1200°C, the DSC samples had the solidification behavior expected from thermodynamic equilibrium calculations. Solidification of the ternary alloys commenced with formation of ternary β and Cu-Al δ phases at 450-550°C; this was followed by β-Sn, and, finally, Cu6Sn5 and Cu-Al γ1. Because of the presence of the retained, high-temperature phases in the alloys, particle size and volume fraction of the room temperature Cu-Al IMC phases were observed to increase when the alloy casting temperature was reduced from 1200°C to 800°C, even though both temperatures are above the calculated liquidus temperature of the alloys. Preliminary electron backscatter diffraction results seemed to show Sn grain refinement in the SAC + Al BGA alloy.

  13. Size effects in tin-based lead-free solder joints: Kinetics of bond formation and mechanical characteristics

    Science.gov (United States)

    Abdelhadi, Ousama Mohamed Omer

    Continuous miniaturization of microelectronic interconnects demands smaller joints with comparable microstructural and structural sizes. As the size of joints become smaller, the volume of intermetallics (IMCs) becomes comparable with the joint size. As a result, the kinetics of bond formation changes and the types and thicknesses of IMC phases that form within the constrained region of the bond varies. This dissertation focuses on investigating combination effects of process parameters and size on kinetics of bond formation, resulting microstructure and the mechanical properties of joints that are formed under structurally constrained conditions. An experiment is designed where several process parameters such as time of bonding, temperature, and pressure, and bond thickness as structural chracteristic, are varied at multiple levels. The experiment is then implemented on the process. Scanning electron microscope (SEM) is then utilized to determine the bond thickness, IMC phases and their thicknesses, and morphology of the bonds. Electron backscatter diffraction (EBSD) is used to determine the grain size in different regions, including the bulk solder, and different IMC phases. Physics-based analytical models have been developed for growth kinetics of IMC compounds and are verified using the experimental results. Nanoindentation is used to determine the mechanical behavior of IMC phases in joints in different scales. Four-point bending notched multilayer specimen and four-point bending technique were used to determine fracture toughness of the bonds containing IMCs. Analytical modeling of peeling and shear stresses and fracture toughness in tri-layer four-point bend specimen containing intermetallic layer was developed and was verified and validated using finite element simulation and experimental results. The experiment is used in conjunction with the model to calculate and verify the fracture toughness of Cu6Sn5 IMC materials. As expected two different IMC phases

  14. Soldering in electronics assembly

    CERN Document Server

    Judd, Mike

    2013-01-01

    Soldering in Electronics Assembly discusses several concerns in soldering of electronic assemblies. The book is comprised of nine chapters that tackle different areas in electronic assembly soldering. Chapter 1 discusses the soldering process itself, while Chapter 2 covers the electronic assemblies. Chapter 3 talks about solders and Chapter 4 deals with flux. The text also tackles the CS and SC soldering process. The cleaning of soldered assemblies, solder quality, and standards and specifications are also discussed. The book will be of great use to professionals who deal with electronic assem

  15. Microstructure evolution and thermomechanical fatigue of solder materials

    NARCIS (Netherlands)

    Matin, M.A.

    2005-01-01

    The microelectronics industry is confronted with the new challenge to produce joints with lead-free solder materials replacing classical tin-lead solders in devices used in many fields (e.g. consumer electronics, road transport, aviation, space-crafts, telecommunication). In service, solder

  16. Ore-lead isotopes and Grenville plate tectonics

    International Nuclear Information System (INIS)

    Farquhar, R.M.; Fletcher, I.R.

    1980-01-01

    Recent advances in the 'whole earth' modelling of evolutionary processes of Pb isotopes shed light upon the origin of the metals found in various types of ore deposits. On the bases of these models and several recently published data sets, we believe that the ore deposits formed in various plate tectonic environments may carry 'isotopic fingerprints' which, when used with other characteristics such as mineral assemblages, may identify the depositional environments of many ore bodies. In the present study Pb-isotopic measurements have been made of a number of Precambrain mineralization types and localities throughout the Central Metasedimentary Belt of the Grenville Province. The data for individual deposits are at best ambiguous, but fall into two groups sufficiently distinctive to allow some degree of 'fingerprint' identification. Comparisons with data from other areas suggest that the major periods of sedimentation within the Central Metasedimentary Belt accompanied plate rifting and/or island arc tectonic activity, with most of the mineralized lead being derived from mantle sources. Detailed comparisons between the Grenville and other regions are uncertain, mainly because there are few detailed high-accuracy data sets from younger, tectonically unambiguous mineral occurrences. We suggest that once these data sets are availble, isotopic fingerprinting may become diagnostic for deposits ranging well back into the Precambrain

  17. Microstructure and mechanical properties of Sn-9Zn-xAl{sub 2}O{sub 3} nanoparticles (x=0–1) lead-free solder alloy: First-principles calculation and experimental research

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Wen-qing; Yu, Xin-ye; Li, Heng; Ma, Le; Zuo, Wei [Taiyuan University of Technology, College of Material Science and Technology, Taiyuan 030024 (China); Dong, Peng; Wang, Wen-xian [Taiyuan University of Technology, College of Material Science and Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-based Materials, Taiyuan 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); Ding, Min, E-mail: dingmin@tyut.edu.cn [Taiyuan University of Technology, College of Material Science and Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-based Materials, Taiyuan 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China)

    2016-12-15

    This paper studies microstructure and mechanical properties of Sn-9Zn-x Al{sub 2}O{sub 3} nanoparticles (x=0–1) lead-free solder alloy. The interface structure, interface energy and electronic properties of Al{sub 2}O{sub 3}/Sn9Zn interface are investigated by first-principle calculation. On the experimental part, in comparison with the plain Sn-9Zn solder, the Al{sub 2}O{sub 3} nanoparticles incorporated into the solder matrix can inhibit the growth of coarse dendrite Sn-Zn eutectic structure and refine grains of the composite solders during the solidification process of the alloys. Moreover, the microhardness and average tensile strength of the solders with addition of Al{sub 2}O{sub 3} nanoparticles increased with the increasing weight percentages of Al{sub 2}O{sub 3} nanoparticles. These improved mechanical properties can be attributed to the microstructure developments and the dispersed Al{sub 2}O{sub 3} nanoparticles.

  18. Multi-scale modeling of elasto-plastic response of SnAgCu lead-free solder alloys at different ageing conditions: Effect of microstructure evolution, particle size effects and interfacial failure

    Energy Technology Data Exchange (ETDEWEB)

    Maleki, Milad; Cugnoni, Joel, E-mail: joel.cugnoni@epfl.ch; Botsis, John

    2016-04-20

    In microelectronics applications, SnAgCu lead-free solder joints play the important role of ensuring both the mechanical and electrical integrity of the components. In such applications, the SnAgCu joints are subjected to elevated homologous temperatures for an extended period of time causing significant microstructural changes and leading to reliability issues. In this study, the link between the change in microstructures and deformation behavior of SnAgCu solder during ageing is explained by developing a hybrid multi-scale microstructure-based modeling approach. Herein, the SnAgCu solder alloy is seen as a three phase metal matrix composite in which Ag{sub 3}Sn and Cu{sub 6}Sn{sub 5} hard intermetallics play the role of reinforcements and Sn the role of a ductile matrix. The hardening of the Sn matrix due to fine intermetallics in the eutectic mixture is modeled by incorporating the mean field effects of geometrically necessary dislocations. Subsequently, a two level homogenization procedure based on micromechanical finite element (FE) models is used to capture the interactions between the different phases. For this purpose, tomographic images of microstructures obtained by Focused Ion Beam (FIB) and synchrotron X-Ray in different ageing conditions are directly used to generate statistically representative volume elements (RVE) using 3D FE models. The constitutive behavior of the solder is determined by sequentially performing two scales of numerical homogenization at the eutectic level and then at the dendrite level. For simplification, the anisotropy of Sn as well as the potential recovery processes have been neglected in the modeling. The observed decrease in the yield strength of solder due to ageing is well captured by the adopted modeling strategy and allows explaining the different ageing mechanisms. Finally, the effects of potential debonding at the intermetallic particle-matrix interface as well as particle fracture on the overall strength of solder are

  19. Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

    KAUST Repository

    Hasheminejad, S. M.; Mitsudharmadi, Hatsari; Winoto, S. H.; Lua, K. B.; Low, H. T.

    2016-01-01

    A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out

  20. FY 1998 report on the waste processing/recycling related technology, 'The R and D of lead-free solder standardization'; 1998 nendo haikibutsu shori recycle kanren gijutsu seika hokokusho. Namari free handa kikakuka nado kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    To reduce the environmental pollution caused by lead eluted from the electronic equipment waste, the R and D on lead-free solder were conducted and the results were summarized. As to the basic characteristics, the evaluation test method was studied in terms of the range of melting temperature, mechanical strength, wettability and joint strength, to select a uniform test method. As the lead-free solder, Sn-Ag alloys were mainly used and mixed in a combination of Cu, Bi and In. Changes in characteristics were made clear by adding trace elements such as Ge, Mn and P. Relating to the applied characteristics, in selection of solder materials, materials were selected for which evaluation of the commercialization is proceeded with from a viewpoint of promotion of commercialization. Concerning the experimental evaluation of characteristics of lead-free solder in mounted substrates, it was indicated that basically lead-free solder can be practically used. Further, it was indicated that the Sn-Ag-Cu-Bi system depends not on solder composition but on active force, printing accuracy and flux characteristic of solder paste, that improvement of solder paste has an effect on mounting characteristics. (NEDO)

  1. Direct Printing of 1-D and 2-D Electronically Conductive Structures by Molten Lead-Free Solder

    Directory of Open Access Journals (Sweden)

    Chien-Hsun Wang

    2016-12-01

    Full Text Available This study aims to determine the effects of appropriate experimental parameters on the thermophysical properties of molten micro droplets, Sn-3Ag-0.5Cu solder balls with an average droplet diameter of 50 μm were prepared. The inkjet printing parameters of the molten micro droplets, such as the dot spacing, stage velocity and sample temperature, were optimized in the 1D and 2D printing of metallic microstructures. The impact and mergence of molten micro droplets were observed with a high-speed digital camera. The line width of each sample was then calculated using a formula over a temperature range of 30 to 70 °C. The results showed that a metallic line with a width of 55 μm can be successfully printed with dot spacing (50 μm and the stage velocity (50 mm∙s−1 at the substrate temperature of 30 °C. The experimental results revealed that the height (from 0.63 to 0.58 and solidification contact angle (from 72° to 56° of the metallic micro droplets decreased as the temperature of the sample increased from 30 to 70 °C. High-speed digital camera (HSDC observations showed that the quality of the 3D micro patterns improved significantly when the droplets were deposited at 70 °C.

  2. Lead-free soldering: Investigation of the Cu-Sn-Sb system along the Sn:Sb = 1:1 isopleth

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Y. [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Borzone, G., E-mail: borzone@chimica.unige.it [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy); Zanicchi, G.; Delsante, S. [Department of Chemistry and Industrial Chemistry, University of Genoa, INSTM UdR Genoa, Via Dodecaneso 31, I-16146 Genoa (Italy)

    2011-02-03

    Research highlights: > In the electronics industry, the solder alloys commonly used for assembly belong to the Sn-Pb system. Fulfilment of the EU RoHS (reduction of hazardous substances) requires the development of new lead-free alloys for applications in electronics, with the same or possibly better characteristics than the traditional Sn-Pb alloys. > This research concerns the investigation of the constitutional properties of the Cu-Sn-Sb system which is considered as lead-free replacement for high-temperature applications. - Abstract: The Cu-Sn-Sb system has been experimentally investigated by a combination of optical microscopy, differential scanning calorimetry (DSC) and electron probe microanalysis (EPMA). DSC was used to identify a total number of five invariant ternary reactions and the Sn:Sb = 1:1 isopleth section up to 65 at.% Cu was constructed by combining the DSC data with the EPMA analyses of annealed alloys and literature information. The composition limits of the binary phases were detected.

  3. Interface between Sn-Sb-Cu solder and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sebo, P., E-mail: Pavel.Sebo@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Svec, P. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janickovic, D.; Illekova, E. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine)

    2011-07-15

    Highlights: {yields} New lead-free solder materials based on Sn-Sb-Cu were designed and prepared. {yields} Melting and solidification temperatures of the solders have been determined. {yields} Cu-substrate/solder interaction has been analyzed and quantified. {yields} Phases formed at the solder-substrate interface have been identified. {yields} Composition and soldering atmospheres were correlated with joint strength. - Abstract: Influence of antimony and copper in Sn-Sb-Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu-solder-Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere - air with the flux and deoxidising N{sub 2} + 10H{sub 2} gas - was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} phases arise. Cu{sub 3}Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu{sub 6}Sn{sub 5} phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

  4. Microstructural and mechanical characterization of melt spun process Sn-3.5Ag and Sn-3.5Ag-xCu lead-free solders for low cost electronic assembly

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa Shalaby, Rizk; Kamal, Mustafa [Metal Physics Laboratory, Physics Department, Faculty of Science, Mansoura University, P.O.Box: 35516, Mansoura (Egypt); Ali, Esmail A.M. [Basic Science Department, Faculty of Engineering, University of Science & Technology (Yemen); Gumaan, Mohammed S., E-mail: m.gumaan1@gmail.com [Metal Physics Laboratory, Physics Department, Faculty of Science, Mansoura University, P.O.Box: 35516, Mansoura (Egypt); Basic Science Department, Faculty of Engineering, University of Science & Technology (Yemen)

    2017-04-06

    This paper aims to investigate the reliability of mechanical and creep behavior for the eutectic Sn-Ag and Sn-Ag-Cu Solder joints rapidly solidified after hot compressing (HC) in terms of structural changes and its relationship with thermal behavior, which has been discussed and compared with their properties before HC process by Mustafa et al. (2016) . These solder joints were prepared by melt-spinning technique and tested by HC at 30 MPa pressure and 150 °C for 90 min, their structural, mechanical and thermal properties after HC process have been investigated by X-ray diffraction (XRD), dynamic resonance techniques (DRT) and differential scanning calorimetry (DSC) techniques respectively and compared with these solders before HC. The results revealed that the pressure caused some fractures on the solders morphology surfaces. But some benefits for these solders have been occurred, like eliminating the internal stresses through recrystallization process whose evidence by the particle size increases after they HC, stabilized structure after HC was due to the metastable phases rearrangements, new intermetallic compounds (IMCs) formation, decreasing, melting temperature range (∆T), lattice strains (ƹ) and entropy change (S). These sequential benefits are considered to be the main reasons which lead to decreasing energy loss (Q{sup −1}), creep rate (É›) and thermal stability enhancement. Elastic modulus increment might be due to low elastic lattice distortions after HC, while the stress exponent (n) reduction refers to viscous glide mechanism of deformation after HC instead of climb deformation mechanism before HC.

  5. The constitutive response of three solder materials

    International Nuclear Information System (INIS)

    Perez-Bergquist, Alejandro G.; Cao Fang; Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T.

    2012-01-01

    Highlights: ► The full constitutive response of three solder materials. ► Test temperatures from −196 °C to 60 °C and strain rates from 10 −3 to >10 3 s −1 . ► Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (−196 °C to 60 °C) and strain rate (10 −3 to >10 3 s −1 ). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  6. The constitutive response of three solder materials

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Bergquist, Alejandro G., E-mail: alexpb@lanl.gov [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States); Cao Fang [Exxon Mobil Research and Engineering Company, Annadale, NJ 08801 (United States); Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T. [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer The full constitutive response of three solder materials. Black-Right-Pointing-Pointer Test temperatures from -196 Degree-Sign C to 60 Degree-Sign C and strain rates from 10{sup -3} to >10{sup 3} s{sup -1}. Black-Right-Pointing-Pointer Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (-196 Degree-Sign C to 60 Degree-Sign C) and strain rate (10{sup -3} to >10{sup 3} s{sup -1}). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  7. Study of silicon chip soldering in high-power transistor housing

    Directory of Open Access Journals (Sweden)

    Vasily S. Anosov

    2017-09-01

    We experimentally assessed the effect of outer housing layer materials and back side chip metallization. For lead-silver soldering of silicon chips, the best housing is that with a nickel outer layer rather than with a gold-plated one, because the resultant thermal resistance is lower and the absence of gold makes the technology cheaper. We obtained a 0.6 K/W thermal resistance for a 24 mm2 chip area.

  8. The lead equivalence of plate glass for diagnostic x-rays

    International Nuclear Information System (INIS)

    Young, B.F.; Morris, N.D.

    1983-01-01

    The effectiveness of plate glass as a radiation protection barrier was determined. For x ray energies between 80 and 140 kVp, the lead equivalence of plate glass is energy independent, but below 80 kVp there is an apparent dependence. A thickness of plate glass of 25 mm for radiation energies between 80 and 140 kVp is equivalent to lead of .3mm thickness. There could be a limited application for the use of plate glass in viewing panels

  9. Mechanical properties of Bi-In-Zn/ Cu solder joint system

    International Nuclear Information System (INIS)

    Ervina Efzan Mohd Noor; Mohammed Noori Ridha; Ahmad Badri Ismail; Nurulakmal Mohd Sharif; Kuan Yew Cheong; Tadashi Ariga; Zuhailawati Hussain

    2009-01-01

    Full text: In recent years, the pollution of environment from lead (Pb) and Pb-containing compounds in microelectronic devices attracts more and more attentions in academia and industry; the lead-free solder alloys begin to replace the lead-based solders in packaging process of some devices and components. In this works, microstructure and mechanical properties of different reflow temperature (80, 100, 120 and 140 degree Celsius) for solder joints on shear strength of Bi-In-Zn lead free solder with low melting temperature of 60 degree Celsius on Cu solder joint has been investigated. This paper will compared the mechanical properties of the Bi-In-Zn lead-free solder alloys with current lead-free solder, Sn-Ag-Cu solder alloy. The fracture surface analyses have been observed by Optical Microscope and were investigated by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) and proved it by X-ray diffraction (XRD). (author)

  10. New technology of lead-tin plating of superconducting RF resonators for the ANU LINAC

    International Nuclear Information System (INIS)

    Lobanov, N.R.; Weisser, D.C.

    2003-01-01

    The RF accelerating resonators for the ANU superconducting LINAC have been re-plated with lead-tin and their performance substantially improved. The re-plating was at first derailed by the appearance of dendrites on the surface. This problem was overcome by a new combination of two techniques. Rather than the standard process of chemically stripping the old Pb and hand polishing the Cu substrate the unsatisfactory Pb surface was mechanically polished and then re-plated. This is enormously easier, faster and doesn't put at risk the thin cosmetic electron beam welds or the repaired ones. Reverse pulse plating was then used to re-establish an excellent superconducting surface. Average acceleration fields of 3.5 to 3.9 MV/m have been achieved. The re-plated resonators will double the energy gain of the accelerator significantly extending capability of the facility research. Lead-tin plating provides fast adequate results with modest equipment and at relatively low cost. SUNY re-plated six high-beta SLRs with 2 microns of Pb-Sn using a modern, commercial, methane-sulfonate process (Lea Ronal Solderon MHS-L) and a simple open-air procedure. This proven success motivated ANU to adopt MSA chemistry and to re-plate the first SLR in November 1998 followed by re-plating all twelve SLRs by November 2002. This increased the booster energy gain by almost 100%

  11. Safety and Health Topics: Lead

    Science.gov (United States)

    ... ammunition, pipes, cable covering, building material, solder, radiation shielding, collapsible tubes, and fishing weights. Lead is also ... lead linings in tanks and radiation protection, leaded glass, work involving soldering, and other work involving lead ...

  12. Evaluation on the characteristics of tin-silver-bismuth solder

    Science.gov (United States)

    Xia, Z.; Shi, Y.; Chen, Z.

    2002-02-01

    Tin-silver-bismuth solder is characterized by its lower melting point, good wetting behavior, and good mechanical property for which it is expected to be a new lead-free solder to replace tin-lead solder. In this article, Sn-3.33Ag-4.83Bi solder was investigated concerning its physical, spreading, and mechanical properties under specific conditions. Cooling curves and DSC results showed that it was close to eutectic composition (m.p. 210° 212 °C). Coefficiency of thermal expansion (CTE) of this solder, between that of PCBs and copper substrates, was beneficial to alleviate the thermal mismatch of the substrates. It was also a good electrical and thermal conductor. Using a rosin-based, mildly activated (RMA) flux, a spreading test indicated that SnAgBi solder paste had good solderability. Meanwhile, the solder had high tensile strength and fracture energy. Its fracture mechanism was a mixture of ductile and brittle fracture morphology. The metallographic and EDAX analyses indicated that it was composed of a tin-based solid solution and some intermetallic compound (IMC) that could strengthen the substrate. However, these large needle-like IMCs would cut the substrate and this resulted in the decreasing of the toughness of the solder.

  13. The addition of red lead to flat plate and tubular valve regulated miners cap lamp lead-acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ferg, E.E.; Loyson, P. [Department of Chemistry, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Poorun, A. [Willard Batteries, P.O. Box 1844, Port Elizabeth 6000 (South Africa)

    2006-04-21

    The study looked at the use of red lead in the manufacturing of valve regulated lead acid (VRLA) miners cap lamp (MCL) batteries that were made with either flat plate or tubular positive electrodes. A problem with using only grey oxide in the manufacture of thick flat plate or tubular electrodes is the poor conversion of the active material to the desired lead dioxide. The addition of red lead to the initial starting material improves the formation efficiency but is considerably more expensive thereby increasing the cost of manufacturing. The study showed that by carefully controlling the formation conditions in terms of the voltage and temperature of a battery, good capacity performance can be achieved for cells made with flat plate electrodes that contain up to 25% red lead. The small amount of red lead in the active cured material reduces the effect of electrode surface sulphate formation and allows the battery to achieve its rated capacity within the first few cycles. Batteries made with flat plate positive electrodes that contained more that 50% red lead showed good initial capacity but had poor structural active material bonding. The study showed that MCL batteries made with tubular positive electrodes that contained less than 75% red lead resulted in a poorly formed electrode with limited capacity utilization. Pickling and soaking times of the tubular electrodes should be kept at a minimum thereby allowing higher active material utilization during subsequent capacity cycling. The study further showed that it is beneficial to use higher formation rates in order to reduce manufacturing time and to improve the active material characteristics. (author)

  14. A Corrosion Investigation of Solder Candidates for High-Temperature Applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Ambat, Rajan

    2009-01-01

    The step soldering approach is being employed in the Multi-Chip module (MCM) technology. High lead containing alloys is one of the solders currently being used in this approach. Au-Sn and Au-Ge based candidate alloys have been proposed as alternative solders for this application. In this work...

  15. Influence of aging treatment on deformation behavior of 96.5Sn3.5Ag lead-free solder alloy during in situ tensile tests

    International Nuclear Information System (INIS)

    Ding, Ying; Wang, Chunqing; Tian, Yanhong; Li, Mingyu

    2007-01-01

    This study investigates the influence of aging treatment on deformation behavior of 96.5Sn3.5Ag eutectic solder alloys with lower strain rate ( -3 s -1 ) during tensile tests under the scanning electron microscope. Results showed that because of the existence of Ag 3 Sn intermetallic particles and the special microstructure of β-Sn phases in Sn3.5Ag solder, grain boundary sliding was not the dominant mechanism any longer for this Pb-free solder. While the interaction of dislocations with the relatively rigid Ag 3 Sn particles began to dominate. For the as-cast specimen, accompanied by partial intragranular cracks, intergranular fracture along the grain boundaries in Sn-Ag eutectic structure or the interphase boundaries between Sn-rich dendrites and Sn-Ag eutectic phases occurred primarily in early tensile stage. However, the boundary behavior was limited by the large Ag 3 Sn particles presented along the Sn-rich dendrites boundaries after aging. Plastic flow was observed in large area, and cracks propagated in a transgranular manner across the Sn-dendrites and Sn-Ag eutectic structure

  16. Correlation Between Pin Misalignment and Crack Length in THT Solder Joints

    Directory of Open Access Journals (Sweden)

    Molnar A.

    2017-06-01

    Full Text Available In this manuscript, correlations were searched for between pin misalignments relative to PCB bores and crack propagation after cyclic thermal shock tests in THT solder joints produced from lead-free solder alloys. In total, 7 compositions were examined including SAC solders with varying Ag, Cu and Ni contents. The crack propagation was initiated by cyclic thermal shock tests with 40°C / +125°C temperature profiles. Pin misalignments relative to the bores were characterized with three attributes obtained from one section of the examined solder joints. Cracks typically originated at the solder/pin or solder/bore interfaces and propagated within the solder. It was shown that pin misalignments did not have an effect on crack propagation, thus, the solder joints’ lifetime.

  17. The metallurgical approach on the solder voids behaviour in surface mount devices

    International Nuclear Information System (INIS)

    Mohabattul Zaman Bukhari

    1996-01-01

    Solder voids are believed to cause poor heat dissiption in the Surface Mount devices and reduce the reliability of the devices at higher operating services. There are a lot of factors involved in creating voids such as gas/flux entrapment, wettability, outgasseous, air bubbles in the solder paste, inconsistency of solder coverage and improper metal scheme selection. This study was done to observe the behaviour of the solder voids in term of flux entrapmentt and wettability. It is believed that flux entrapment and wettability are verify this hypothesis. Two types of metal scheme were chosen which are Nickel (Ni) plated and Tin (Sn) plated heatsink. X-ray techniques such as Radiographic Inspection Analysis and EDAX were used to detect the minute solder voids. The solder voids observed on the heatsinks and Copper shims after the reflow process are believed to be a non contact voids that resulted from some portion of the surface not wetting properly

  18. Concurrent nucleation, formation and growth of two intermetallic compounds (Cu6Sn5 and Cu3Sn) during the early stages of lead-free soldering

    International Nuclear Information System (INIS)

    Park, M.S.; Arróyave, R.

    2012-01-01

    This study investigates the concurrent nucleation, formation and growth of two intermetallic compounds (IMCs), Cu 6 Sn 5 (η) and Cu 3 Sn (ε), during the early stages of soldering in the Cu–Sn system. The nucleation, formation and growth of the IMC layers is simulated through a multiphase-field model in which the concurrent nucleation of both IMC phases is considered to be a stochastic Poisson process with nucleation rates calculated from classical nucleation theory. CALPHAD thermodynamic models are used to calculate the local contributions to the free energy of the system and the driving forces for precipitation of the IMC phases. The nucleation parameters of the η phase are estimated from experimental results and those of the ε phase are assumed to be similar. A parametric investigation of the effects of model parameters (e.g. grain boundary (GB) diffusion rates, interfacial and GB energies) on morphological evolution and IMC layer growth rate is presented and compared with previous works in which nucleation was ignored . In addition, the resulting growth rates are compared with the available literature and it is found that, for a certain range in the model parameters, the agreement is quite satisfactory. This work provides valuable insight into the dominant mechanisms for mass transport as well as morphological evolution and growth of IMC layers during early stages of Pb-free soldering.

  19. Lead poisoning

    Science.gov (United States)

    ... drinking water in homes containing pipes that were connected with lead solder . Although new building codes require ... lead in their bodies when they put lead objects in their mouths, especially if they swallow those ...

  20. A new method for soldering particle-reinforced aluminum metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jinbin; Mu, Yunchao [Zhongyuan University of Technology, Zhengzhou 450007 (China); Luo, Xiangwei [Zhengzhou University, Zhengzhou 450002 (China); Niu, Jitai, E-mail: niujitai@163.com [Zhongyuan University of Technology, Zhengzhou 450007 (China)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. Black-Right-Pointing-Pointer The nickel plating is required on the surface of the composites before soldering. Black-Right-Pointing-Pointer Low welding temperature is set to avoid overheating of the matrix. Black-Right-Pointing-Pointer Chemical and metallurgical bonding of composites and Kovar is carried out. Black-Right-Pointing-Pointer High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al-SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe-Ni-Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn-Cd-Ag-Cu) with a melting point of about 400 Degree-Sign C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)-Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al-SiC composite.

  1. A new method for soldering particle-reinforced aluminum metal matrix composites

    International Nuclear Information System (INIS)

    Lu, Jinbin; Mu, Yunchao; Luo, Xiangwei; Niu, Jitai

    2012-01-01

    Highlights: ► Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. ► The nickel plating is required on the surface of the composites before soldering. ► Low welding temperature is set to avoid overheating of the matrix. ► Chemical and metallurgical bonding of composites and Kovar is carried out. ► High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al–SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe–Ni–Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn–Cd–Ag–Cu) with a melting point of about 400 °C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)–Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al–SiC composite.

  2. Lead poisoning following ingestion of pieces of lead roofing plates: pica-like behavior in an adult.

    Science.gov (United States)

    Sabouraud, Sabine; Testud, François; Descotes, Jacques; Benevent, Monique; Soglu, Gilbert

    2008-03-01

    A 37-year-old man was admitted to hospital after complaining of abdominal pain for the past two weeks. On admission the abdominal radiograph showed multiple radio-opaque flecks dispersed throughout the gastrointestinal tract. Blood testing showed hemoglobin level 8.7 g/dL and a blood lead level of 112.4 microg/dL. The family interview revealed that the patient had pica-like behavior since childhood. He was a site foreman and had been ingesting pieces of roofing plates for a few weeks. The patient was treated with laxatives and CaNa(2)EDTA therapy was initiated. The blood lead level then dropped to 69.9 microg/dL. The patient received two subsequent courses of oral succimer and the blood lead level decreased to 59 microg/dL 21 days after the first course. The follow-up abdominal X-ray 20 days after the first examination was normal. Four months later, an outpatient follow-up visit showed a blood lead level within normal limits (14.5 microg/dL) and a psychiatric follow-up was initiated. Lead poisoning following the ingestion of lead-containing foreign bodies is particularly rare in adults, while it is sometimes observed in children. Pica behavior is a well-identified risk factor of lead intoxication in children but is quite exceptional in adults, where it is usually considered to be a psychiatric condition. Other unusual sources of lead poisoning include the ingestion of lead bullets, ceramic lead glaze or glazed earthenware, lead-contaminated candies, ethnic or herbal remedies.

  3. Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

    KAUST Repository

    Hasheminejad, S. M.

    2016-01-05

    A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out for a Reynolds number based on the pattern wavelength (λ) of 3080. The results depict the onset, development and breakdown of the vortical structures within the flat plate boundary layer. Moreover, the effect of one spanwise array of holes with diameter of 0.2λ (=3 mm) was examined. This investigation was done on two different flat plates with holes placed at the location x/λ = 2 downstream of the troughs and peaks. The presence of holes after troughs does not show any significant effect on the vortical structures. However, the plate with holes after peaks noticeably delays the vortex breakdown. In this case, the “mushroom-like” vortices move away from the wall and propagate downstream with stable vortical structures. The vortex growth is halted further downstream but start to tilt aside.

  4. Impurity Effects in Electroplated-Copper Solder Joints

    Directory of Open Access Journals (Sweden)

    Hsuan Lee

    2018-05-01

    Full Text Available Copper (Cu electroplating is a mature technology, and has been extensively applied in microelectronic industry. With the development of advanced microelectronic packaging, Cu electroplating encounters new challenges for atomic deposition on a non-planar substrate and to deliver good throwing power and uniform deposit properties in a high-aspect-ratio trench. The use of organic additives plays an important role in modulating the atomic deposition to achieve successful metallic coverage and filling, which strongly relies on the adsorptive and chemical interactions among additives on the surface of growing film. However, the adsorptive characteristic of organic additives inevitably results in an incorporation of additive-derived impurities in the electroplated Cu film. The incorporation of high-level impurities originating from the use of polyethylene glycol (PEG and chlorine ions significantly affects the microstructural evolution of the electroplated Cu film, and the electroplated-Cu solder joints, leading to the formation of undesired voids at the joint interface. However, the addition of bis(3-sulfopropyl disulfide (SPS with a critical concentration suppresses the impurity incorporation and the void formation. In this article, relevant studies were reviewed, and the focus was placed on the effects of additive formula and plating parameters on the impurity incorporation in the electroplated Cu film, and the void formation in the solder joints.

  5. Development of gold based solder candidates for flip chip assembly

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    Flip chip technology is now rapidly replacing the traditional wire bonding interconnection technology in the first level packaging applications due to the miniaturization drive in the microelectronics industry. Flip chip assembly currently involves the use of high lead containing solders...

  6. Effect of micron size Ni particle addition in Sn–8Zn–3Bi lead-free solder alloy on the microstructure, thermal and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Billah, Md. Muktadir; Shorowordi, Kazi Mohammad; Sharif, Ahmed, E-mail: asharif@mme.buet.ac.bd

    2014-02-05

    Highlights: • Ni-added Sn-Zn-Bi were characterized metallographically, thermally and mechanically. • The volume fraction of α-Zn phase increased with both Bi and Ni in Sn-Zn-Bi alloys. • Micron-sized Ni particles reacted with neither Sn nor Zn to form intermetallics. • Better combination of thermal and mechanical properties can be achieved with Ni. -- Abstract: Micron-sized Ni particle-reinforced Sn–8Zn–3Bi composite solders were prepared by mechanically dispersing Ni particles into Sn–8Zn–3Bi alloy and the bulk properties of the composite solder alloy were characterized metallographically, thermally and mechanically. Different percentage of Ni particle viz. 0.25, 0.5 and 1 wt.% were added in the liquid Sn–8Zn–3Bi alloy and then cast into the metal molds. Melting behavior was studied by differential thermal analyzer (DTA). Microstructural investigation was carried out by both optical and scanning electron microscope. Tensile properties were determined using an Instron Universal Testing Machine at a strain rate 3.00 mm/min. The results indicated that the Ni addition increased the melting temperature of Sn–8Zn–3Bi alloy. The addition of Ni was also found to increase the solidification range. In the Sn–8Zn–3Bi alloy, needle-shaped α-Zn phase was found to be uniformly distributed in the β-Sn matrix. However, it was found that the small amount of Ni addition in Sn–8Zn–3Bi alloy refined the Zn needles throughout the matrix. Also an enhanced precipitation of Zn in the structure was observed with the addition of Ni. All these structural changes improved the mechanical properties like tensile strength and hardness of the newly developed quaternary alloy.

  7. Assessment of potential solder candidates for high temperature applications

    DEFF Research Database (Denmark)

    pressure to eliminate lead containing materials despite the fact that materials for high Pb containing alloys are currently not affected by any legislations. A tentative assessment was carried out to determine the potential solder candidates for high temperature applications based on the solidification...... criterion, phases predicted in the bulk solder and the thermodynamic stability of chlorides. These promising solder candidates were precisely produced using the hot stage microscope and its respective anodic and cathodic polarization curves were investigated using a micro-electrochemical set up...

  8. Kinetics of intermetallic phase formation at the interface of Sn-Ag-Cu-X (X = Bi, In) solders with Cu substrate

    International Nuclear Information System (INIS)

    Hodulova, Erika; Palcut, Marian; Lechovic, Emil; Simekova, Beata; Ulrich, Koloman

    2011-01-01

    Highlights: → In substitutes Sn in intermetallic compounds formed at the Cu-solder interface. → Bi and In decrease the parabolic rate constant of Cu 3 Sn layer growth. → In increases the parabolic rate constant of Cu 6 Sn 5 layer growth. → High In concentrations should be avoided since they may lead to a pre-mature solder joint degradation. - Abstract: The effects of Bi and In additions on intermetallic phase formation in lead-free solder joints of Sn-3.7Ag-0.7Cu; Sn-1.0Ag-0.5Cu-1.0Bi and Sn-1.5Ag-0.7Cu-9.5In (composition given in weight %) with copper substrate are studied. Soldering of copper plate was conducted at 250 deg. C for 5 s. The joints were subsequently aged at temperatures of 130-170 deg. C for 2-16 days in a convection oven. The aged interfaces were analyzed by optical microscopy and energy dispersive X-ray spectroscopy (EDX) microanalysis. Two intermetallic layers are observed at the interface - Cu 3 Sn and Cu 6 Sn 5 . Cu 6 Sn 5 is formed during soldering. Cu 3 Sn is formed during solid state ageing. Bi and In decrease the growth rate of Cu 3 Sn since they appear to inhibit tin diffusion through the grain boundaries. Furthermore, indium was found to produce a new phase - Cu 6 (Sn,In) 5 instead of Cu 6 Sn 5 , with a higher rate constant. The mechanism of the Cu 6 (Sn,In) 5 layer growth is discussed and the conclusions for the optimal solder chemical composition are presented.

  9. Effect of solder bump size on interfacial reactions during soldering between Pb-free solder and Cu and Ni/ Pd/ Au surface finishes

    International Nuclear Information System (INIS)

    NorAkmal, F.; Ourdjini, A.; Azmah Hanim, M.A.; Siti Aisha, I.; Chin, Y.T.

    2007-01-01

    Flip chip technology provides the ultimate in high I/ O-density and count with superior electrical performance for interconnecting electronic components. Therefore, the study of the intermetallic compounds was conducted to investigate the effect of solder bumps sizes on several surface finishes which are copper and Electroless Nickel/ Electroless Palladium/ Immersion Gold (ENEPIG) which is widely used in electronics packaging as surface finish for flip-chip application nowadays. In this research, field emission scanning electron microscopy (FESEM) analysis was conducted to analyze the morphology and composition of intermetallic compounds (IMCs) formed at the interface between the solder and UBM. The IMCs between the SAC lead-free solder with Cu surface finish after reflow were mainly (Cu, Ni) 6 Sn 5 and Cu 6 Sn 5 . While the main IMCs formed between lead-free solder on ENEPIG surface finish are (Ni, Cu) 3 Sn 4 and Ni 3 Sn 4 . The results from FESEM with energy dispersive x-ray (EDX) have revealed that isothermal aging at 150 degree Celsius has caused the thickening and coarsening of IMCs as well as changing them into more spherical shape. The thickness of the intermetallic compounds in both finishes investigated was found to be higher in solders with smaller bump size. From the experimental results, it also appears that the growth rate of IMCs is higher when soldering on copper compared to ENEPIG finish. Besides that, the results also showed that the thickness of intermetallic compounds was found to be proportional to isothermal aging duration. (author)

  10. Development of a soft-soldering system for aluminum

    Science.gov (United States)

    Falke, W. L.; Lee, A. Y.; Neumeier, L. A.

    1983-03-01

    The method employs application of a thin nickel copper alloy coating to the substrate, which enables the tin lead solders to wet readily and spread over the areas to be joined. The aluminum substrate is mechanically or chemically cleaned to facilitate bonding to a minute layer of zinc that is subsequently applied, with an electroless zincate solution. The nickel copper alloy (30 to 70 pct Ni) coating is then applied electrolytically over the zinc, using immersion cell or brush coating techniques. Development of acetate electrolytes has permitted deposition of the proper alloys coatings. The coated areas can then be readily joined with conventional tin lead solders and fluxs. The joints so formed are ductile, strong, and relatively corrosion resistant, and exhibit strengths equivalent to those formed on copper and brass when the same solders and fluxes are used. The method has also been employed to soft solder magnesium alloys.

  11. An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.

    1998-10-15

    A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

  12. Development of Streamwise Counter-Rotating Vortices in Flat Plate Boundary Layer Pre-set by Leading Edge Patterns

    KAUST Repository

    Hasheminejad, S.M.; Mitsudharmadi, Hatsari; Winoto, S.H.; Low, H.T.; Lua, K.B.

    2017-01-01

    Development of streamwise counter-rotating vortices induced by leading edge patterns with different pattern shape is investigated using hot-wire anemometry in the boundary layer of a flat plate. A triangular, sinusoidal and notched patterns

  13. Effects of Metallic Nanoparticles on Interfacial Intermetallic Compounds in Tin-Based Solders for Microelectronic Packaging

    Science.gov (United States)

    Haseeb, A. S. M. A.; Arafat, M. M.; Tay, S. L.; Leong, Y. M.

    2017-10-01

    Tin (Sn)-based solders have established themselves as the main alternative to the traditional lead (Pb)-based solders in many applications. However, the reliability of the Sn-based solders continues to be a concern. In order to make Sn-based solders microstructurally more stable and hence more reliable, researchers are showing great interest in investigating the effects of the incorporation of different nanoparticles into them. This paper gives an overview of the influence of metallic nanoparticles on the characteristics of interfacial intermetallic compounds (IMCs) in Sn-based solder joints on copper substrates during reflow and thermal aging. Nanocomposite solders were prepared by mechanically blending nanoparticles of nickel (Ni), cobalt (Co), zinc (Zn), molybdenum (Mo), manganese (Mn) and titanium (Ti) with Sn-3.8Ag-0.7Cu and Sn-3.5Ag solder pastes. The composite solders were then reflowed and their wetting characteristics and interfacial microstructural evolution were investigated. Through the paste mixing route, Ni, Co, Zn and Mo nanoparticles alter the morphology and thickness of the IMCs in beneficial ways for the performance of solder joints. The thickness of Cu3Sn IMC is decreased with the addition of Ni, Co and Zn nanoparticles. The thickness of total IMC layer is decreased with the addition of Zn and Mo nanoparticles in the solder. The metallic nanoparticles can be divided into two groups. Ni, Co, and Zn nanoparticles undergo reactive dissolution during solder reflow, causing in situ alloying and therefore offering an alternative route of alloy additions to solders. Mo nanoparticles remain intact during reflow and impart their influence as discrete particles. Mechanisms of interactions between different types of metallic nanoparticles and solder are discussed.

  14. Thermal and mechanical properties of lead-free SnZn–xNa casting alloys, and interfacial chemistry on Cu substrates during the soldering process

    Energy Technology Data Exchange (ETDEWEB)

    Gancarz, Tomasz, E-mail: tomasz.gancarz@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow (Poland); Bobrowski, Piotr; Pstruś, Janusz [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow (Poland); Pawlak, Sylwia [Wroclaw Research Centre EIT+, Wroclaw (Poland)

    2016-09-15

    The microstructural features, thermal properties and mechanical properties of eutectic Sn–Zn alloys with varying Na content (0.1, 0.2, 0.5, 1.0 3.0 and 5.0 at. %) were examined in this study. In the scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analysis data, precipitates of NaSn were observed. The addition of Na to eutectic Sn–Zn alloy improved the mechanical properties and increased electrical resistivity, and reduced the coefficient of thermal expansion; however, the melting point did not change. Wettability tests carried out using Na-doped Sn–15Zn alloys on Cu substrates showed the formation of Cu–Zn phases at the interfaces. Wettability studies were performed using flux ALU33 after 60, 180, 480, 900, 1800 and 3600 s of contact, at temperatures of 230, 250, 280 and 320 °C. The experiments were designed to demonstrate the effect of Na addition on the formation and growth kinetics of Cu{sub 5}Zn{sub 8} and CuZn{sub 4} phases, which were identified using XRDs and EDS. The addition of Na to SnZn causes a reduction in the thickness of the intermetallic compounds layer created at the interface between the liquid solder and the Cu substrate, and an increase in the activation energy of the Cu{sub 5}Zn{sub 8} phase compared to eutectic SnZn. - Highlights: • Precipitates of NaSn was observed and confirmed using TEM and XRD. • Addition Na to eutectic SnZn cussed increased the mechanical properties. • IMCs of Na–Zn and Na–Sn increased electrical resistivity and reduced the CTE. • IMCs layers CuZn{sub 4} and Cu{sub 5}Zn{sub 8} was found at the interface. • Na content changing the character of growth CuZn{sub 4} layer in SnZnNa alloys.

  15. Reliability of soldered joints for automotive electronic devices; Denso buhin ni okeru handa setsugo no shinraisei

    Energy Technology Data Exchange (ETDEWEB)

    Kita, T; Mukaibo, N; Ando, K; Moriyama, M [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    Concerning the tin and lead eutectic solder, we have evaluated the reliability of three factors of intermetallic compound layer, creep and vibration which cause solder degradation. First, the stress factor was extracted from investigating the mechanism of degradation, and the best acceleration test method was fixed. Next, the acceleration test was executed to find the stress dependency and the tendency of solder degradation was modeled numerically. While the environmental stress frequency was obtained and they were put together by using a minor method, which enabled us to predict the life span of solder on the market with precision. 5 refs., 13 figs.

  16. Soldering of Nanotubes onto Microelectrodes

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing sold...... bonds were consistently found to be mechanically stronger than the carbon nanotubes.......Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...

  17. Laser Soldering of Rat Skin Using a Controlled Feedback System

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Nourbakhsh

    2009-03-01

    Full Text Available Introduction: Laser tissue soldering using albumin and indocyanine green dye (ICG is an effective technique utilized in various surgical procedures. The purpose of this study was to perform laser soldering of rat skin under a feedback control system and compare the results with those obtained using standard sutures. Material and Methods: Skin incisions were made over eight rats’ dorsa, which were subsequently closed using different wound closure interventions in two groups: (a using a temperature controlled infrared detector or (b by suture. Tensile strengths were measured at 2, 5, 7 and 10 days post-incision. Histological examination was performed at the time of sacrifice. Results: Tensile strength results showed that during the initial days following the incisions, the tensile strengths of the sutured samples were greater than the laser samples. However, 10 days after the incisions, the tensile strengths of the laser soldered incisions were higher than the sutured cuts. Histopathological examination showed a preferred wound healing response in the soldered skin compared with the control samples. The healing indices of the laser soldered repairs (426 were significantly better than the control samples (340.5. Conclusion: Tissue feedback control of temperature and optical changes in laser soldering of skin leads to a higher tensile strength and better histological results and hence this method may be considered as an alternative to standard suturing.

  18. Influence of ZnO nano-particles addition on thermal analysis, microstructure evolution and tensile behavior of Sn–5.0 wt% Sb–0.5 wt% Cu lead-free solder alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fouda, A.N., E-mail: alynabieh@yahoo.com [Physics Department, Faculty of Science, Suez-Canal University, 41522 Ismailia (Egypt); Eid, E.A., E-mail: dr_eid_hti@yahoo.com [Basic Science Department, Higher Technological Institute, 44629 10th of Ramadan City (Egypt)

    2015-04-24

    Sn–5 wt%Sb–0.5 wt%Cu (plain SSC505) and Sn–5 wt%Sb–0.5 wt%Cu–0.5 wt% ZnO (SSC-ZnO) composite solder alloys have been studied. The variation in thermal behavior, microstructure and tensile characteristics associated with mixing of 0.5 wt% ZnO nano-metric particles to plain SSC505 solder were investigated. A slight increment in the melting temperature [ΔT{sub m}=0.89 °C] was recorded using differential scanning calorimetry (DSC) after addition of ZnO. X-Ray diffraction (XRD) analysis confirmed the existence of β-Sn, SbSn and Cu{sub 6}Sn{sub 5} intermetallic compounds (IMCs) beside some of ZnO planes in SSC-ZnO composite solder. Field emission scanning electronic microscope (FE-SEM) investigation of SSC-ZnO composite solder revealed a homogenous uniform distribution, size refinement of IMCs and β-Sn grains. Addition of ZnO nano-metric particles into the plain SSC505 enhanced the yield stress σ{sub YS} by ~12% and improved the ultimate tensile strength σ{sub UTS} by ~13%. In addition, adding ZnO nano-metric particles was found to be effective for reducing ductility by ~43% of the plain solder due to the refinement of β-Sn grains within SSC-ZnO composite solder. - Highlights: • Melting point of SSC505-ZnO composite solder is slightly increased by 0.89 {sup ο}C compared with the plain SSC505 solder. • XRD and EDX analysis reflect the presence of SbSn, Cu{sub 6}Sn{sub 5} IMCs. • EF-SEM images of SSC-ZnO composite solder revealed homogenous uniform distribution of β-Sn grains and fine IMC particles. • A detectable improvement in the Young modulus, ultimate tensile strength and yield strength were observed after addition of 0.5 wt% ZnO nano-metric particles.

  19. On the problem of soldering refractory metals with silver-containing solders

    International Nuclear Information System (INIS)

    Anikeev, E.F.; Andryushchenko, V.I.; Chepelenko, V.N.; Batov, V.M.

    1981-01-01

    The processes of wetting, spreading and interphase interactions of copper-silver liquid alloys alloyed with Ni and Si, with niobium, tantalum, molybdenum, tungsten, 12Kh18N10T steel and nickel are studied. It has been determined that Ni or Si additions into the copper-silver solder improve the wetting and adhesion. When soldering with the alloy containing Ni additions, the strength of a soldered Joint grows with the increase of soldering duration while soldering with the alloy containing Si additions, the strength decreases. That is why Ni-containing solders are preferable for soldering thick-walled structures, and Si-containing solders - for thin-walled structures [ru

  20. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    Science.gov (United States)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. PMID:27877786

  1. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    International Nuclear Information System (INIS)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. (review)

  2. Locked plating of distal femur fractures leads to inconsistent and asymmetric callus formation.

    Science.gov (United States)

    Lujan, Trevor J; Henderson, Chris E; Madey, Steven M; Fitzpatrick, Dan C; Marsh, J Lawrence; Bottlang, Michael

    2010-03-01

    Locked plating constructs may be too stiff to reliably promote secondary bone healing. This study used a novel imaging technique to quantify periosteal callus formation of distal femur fractures stabilized with locking plates. It investigated the effects of cortex-to-plate distance, bridging span, and implant material on periosteal callus formation. Retrospective cohort study. One Level I and one Level II trauma center. Sixty-four consecutive patients with distal femur fractures (AO types 32A, 33A-C) stabilized with periarticular locking plates. Osteosynthesis using indirect reduction and bridge plating with periarticular locking plates. Periosteal callus size on lateral and anteroposterior radiographs. Callus size varied from 0 to 650 mm2. Deficient callus (20 mm2 or less) formed in 52%, 47%, and 37% of fractures at 6, 12, and 24 weeks postsurgery, respectively. Callus formation was asymmetric, whereby the medial cortex had on average 64% more callus (P=0.001) than the anterior or posterior cortices. A longer bridge span correlated minimally with an increased callus size at Week 6 (P=0.02), but no correlation was found at Weeks 12 and 24 postsurgery. Compared with stainless steel plates, titanium plates had 76%, 71%, and 56% more callus at Week 6 (P=0.04), Week 12 (P=0.03), and Week 24 (P=0.09), respectively. Stabilization of distal femur fractures with periarticular locking plates can cause inconsistent and asymmetric formation of periosteal callus. A larger bridge span only minimally improves callus formation. The more flexible titanium plates enhanced callus formation compared with stainless steel plates.

  3. Levels of arsenic, cadmium, lead and mercury in the branchial plate and muscle tissue of mobulid rays

    International Nuclear Information System (INIS)

    Ooi, Michelle S.M.; Townsend, Kathy A.; Bennett, Michael B.; Richardson, Anthony J.; Fernando, Daniel; Villa, Cesar A.; Gaus, Caroline

    2015-01-01

    Highlights: • Branchial plate and muscle tissue from mobulid rays were analysed for certain metals. • Mean concentrations of cadmium in Mobula japanica were above the EC ML. • Mean inorganic arsenic concentration in Mobula japanica muscle equalled the FSANZ ML. • Mean concentration of lead in Manta alfredi muscle tissue exceeded EC and Codex MLs. • There were significant correlations between the types of tissues for some metals. - Abstract: Mobulid rays are targeted in fisheries for their branchial plates, for use in Chinese medicine. Branchial plate and muscle tissue from Mobula japanica were collected from fish markets in Sri Lanka, and muscle tissue biopsies from Manta alfredi in Australia. These were analysed for arsenic, cadmium, lead and mercury and compared to maximum levels (MLs) set by Food Standards Australia and New Zealand (FSANZ), European Commission (EC) and Codex Alimentarius Commission. The estimated intake for a vulnerable human age group was compared to minimal risk levels set by the Agency for Toxic Substances and Disease Registry. The mean inorganic arsenic concentration in M. japanica muscle was equivalent to the FSANZ ML while cadmium exceeded the EC ML. The mean concentration of lead in M. alfredi muscle tissue exceeded EC and Codex MLs. There were significant positive linear correlations between branchial plate and muscle tissue concentrations for arsenic, cadmium and lead

  4. Negative plate macropore surfaces in lead-acid batteries: Porosity, Brunauer-Emmett-Teller area, and capacity

    Energy Technology Data Exchange (ETDEWEB)

    D' Alkaine, C.V.; de O. Brito, G.A. [Group of Electrochemistry and Polymers, DQ-UFSCar, Rodovia Washington Luis, Km 235, CP 676, 13565-905 Sao Carlos (SP) (Brazil)

    2009-06-01

    We propose an explanation for the production of an electrochemically active area during the electrochemical formation of lead-acid battery negative plates based on solid-state reactions. Our proposal is supported by experimental data. This study includes a critical review of the literature on charge/discharge mechanisms, porosity, and BET area. The critical review, through the latter two parameters, indicates the existence of both macro and micropores in positive plates, but only macropores in negative plates, with characteristic surface roughness. In the present paper the surface sulfation of the precursor is controlled using various acidic, neutral and alkaline solutions during an electrochemical formation process that does not include soaking. Our results confirm that variable roughness can be produced at the negative plate macropore surfaces. The morphological changes produced by different formation conditions are assessed by measuring the macroporosity, BET area, and capacity of single negative plates. Based on these concepts, a method was developed and applied to measure independently the contributions of geometrical surface macroporosity and roughness to the negative plate capacity. (author)

  5. Solder joint technology materials, properties, and reliability

    CERN Document Server

    Tu, King-Ning

    2007-01-01

    Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

  6. Long-Term Effects of Soldering By-Products on Nickel-Coated Copper Wire

    Science.gov (United States)

    Rolin, T. D.; Hodge, R. E.

    2008-01-01

    An analysis of thirty-year-old, down graded flight cables was conducted to determine the makeup of a green material on the surface of the shielded wire near soldered areas and to ascertain if the green material had corroded the nickel-coated copper wire. Two likely candidates were possible due to the handling and environments to which these cables were exposed. The flux used to solder the cables is known to contain abietic acid, a carboxylic acid found in many pine rosins used for the soldering process. The resulting material copper abietate is green in color and is formed during the application of heat during soldering operations. Copper (II) chloride, which is also green in color is known to contaminate flight parts and is corrosive. Data is presented that shows the material is copper abietate, not copper (II) chloride, and more importantly that the abietate does not aggressively attack nickel-plated copper wire.

  7. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    hybrid circuit assembly, component lead tinning, and wire tinning. .... The mesh model was built and optimized with 599920 hybrid nodes as shown in figure 9. ... conducted to track the fluid motions of the two phases (i.e., molten solder and air).

  8. Application of a novel bone osteotomy plate leads to reduction in heat-induced bone tissue necrosis in sheep.

    Science.gov (United States)

    Bekić, Marijo; Davila, Slavko; Hrskanović, Mato; Bekić, Marijana; Seiwerth, Sven; Erdeljić, Viktorija; Capak, Darko; Butković, Vladimir

    2008-12-01

    Previous studies have shown substantial effect thermal damage can have on new bone formation following osteotomy. In this study we evaluated the extent of thermal damage which occurs in four different methods of osteotomy and the effects it can have on bone healing. We further wanted to test whether a special osteotomy plate we constructed can lead to diminished heat generation during osteotomy and enhanced bone healing. The four methods evaluated included osteotomy performed by chisel, a newly constructed osteotomy plate, Gigly and oscillating saw. Twelve adult sheep underwent osteotomy performed on both tibiae. Bone fragments were stabilized using a fixation plate. Callus size was assessed using standard radiographs. Densitometry and histological evaluation were performed at 8 weeks following osteotomy. Temperature measurements were performed both in vivo during the operation, and ex vivo on explanted tibiae. The defects healed without complications and showed typical course of secondary fracture healing with callus ingrowth into the osteotomy gap. Radiographic examination of bone healing showed a tendency towards more callus formation in bones osteotomized using Gigly and oscillating saw, but this difference lacked significance. Use of Gigly and oscillating saw elicited much higher temperatures at the bone cortex surface, which subsequently lead to slightly impaired bone healing according to histological analysis. BMD was equal among all bones. In conclusion, the time required for complete healing of the defect differed depended greatly on the instruments used. The newly constructed osteotomy plate showed best results based on histological findings of capillary and osteoblast density.

  9. Active control of noise amplification in the flow over a square leading-edge flat plate utilizing DBD plasma actuator

    Science.gov (United States)

    Yadong, HUANG; Benmou, ZHOU

    2018-05-01

    Perturbation is generally considered as the flow noise, and its energy can gain transient growth in the separation bubble. The amplified perturbations may cause unstable Kelvin–Helmohltz vortices which induce the three-dimensional transition. Active control of noise amplification via dielectric barrier discharge plasma actuator in the flow over a square leading-edge flat plate is numerically studied. The actuator is installed near the plate leading-edge where the separation bubble is formed. The maximum energy amplification of perturbations is positively correlated with the separation bubble scale which decreases with the increasing control parameters. As the magnitude of noise amplification is reduced, the laminar-turbulent transition is successfully suppressed.

  10. NUMERICAL AND EXPERIMENTAL INVESTIGATION ON THE FLUTTER OF CANTILEVERED PLATES WITH FREE LEADING EDGE IN AXIAL FLOW

    Directory of Open Access Journals (Sweden)

    I. P. G. SOPAN RAHTIKA

    2017-10-01

    Full Text Available This paper reports the results of the numerical and experimental investigation on the flutter of cantilevered thin flat plates with free leading edge in axial flow. Three methods of in-vacuo modal analyses of the plates are presented and compared in this paper, namely the finite element modal analysis using ANSYS STUDENT Modal, the analytical beam model, and the experimental modal analysis. In this study, the numerical Fluid Structure Interaction was performed using the ANSYS STUDENT Structural Transient Analysis and ANSYS STUDENT CFX to obtain the system response in the time domain. Furthermore, the experimental investigation was conducted in the smooth flow of a wind tunnel to observe the flutter speeds of the plates and their vibration characteristics. The plates’ vibration behaviors were mapped on the normalized air speed. The normalized air speed can be divided into four speed zones based on the experimental plates’ vibration characteristics. A new finding observed during the experiments is the presence of intermittent vibration behavior that is unique to the free leading edge configuration and has not been reported by other researchers in the earlier references of the clamped leading edge configuration. The potential application of this Fluid Structure Interaction configuration to wind harvesting is inquired.

  11. Electrochemical corrosion behaviour of lead-free Sn-8.5 Zn-X Ag-0.1 Al-0.5 Ga solder in 3.5% NaCl solution

    International Nuclear Information System (INIS)

    Mohanty, Udit Surya; Lin, K.-L.

    2005-01-01

    The electrochemical corrosion behaviour of Pb-free Sn-8.5 Zn-X Ag-0.1 Al-0.5 Ga solder in 3.5% NaCl solution was investigated by using potentiodynamic polarization methods, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analysis. The results obtained from polarization studies showed that an increase in the Ag content from 0.1 to 1.5 wt% decreased the corrosion current density (I corr ) and shifted the corrosion potential (E corr ) towards more noble values. These changes were also reflected in the linear polarization resistance (LPR), corrosion rate, anodic Tafel slope (b A ) and the cathodic Tafel slope (b c ) values, respectively. Passivation behaviour was noted in the Sn-Zn-X Ag-Al-Ga solders with Ag content > 0.1 wt%. The oxides and hydroxides of zinc were responsible for the formation of passive film. Presence of Ag atoms in the oxide layer also improved the passivation behaviour of solders to a certain extent. X-ray photoelectron spectroscopy revealed that two different oxygen species were formed on the surface films, one was assigned to OH - in Zn(OH) 2 and the other to O 2 - in ZnO. XPS depth profile results revealed that the two species had different depth distribution in the films. SEM and EDX analyses confirmed SnCl 2 as the major corrosion product formed after the electrochemical experiments

  12. Handbook of machine soldering SMT and TH

    CERN Document Server

    Woodgate, Ralph W

    1996-01-01

    A shop-floor guide to the machine soldering of electronics Sound electrical connections are the operational backbone of every piece of electronic equipment-and the key to success in electronics manufacturing. The Handbook of Machine Soldering is dedicated to excellence in the machine soldering of electrical connections. Self-contained, comprehensive, and down-to-earth, it cuts through jargon, peels away outdated notions, and presents all the information needed to select, install, and operate machine soldering equipment. This fully updated and revised volume covers all of the new technologies and processes that have emerged in recent years, most notably the use of surface mount technology (SMT). Supplemented with 200 illustrations, this thoroughly accessible text Describes reflow and wave soldering in detail, including reflow soldering of SMT boards and the use of nitrogen blankets * Explains the setup, operation, and maintenance of a variety of soldering machines * Discusses theory, selection, and control met...

  13. Device for filling tubular electrode plates for lead batteries. Vorrichtung zum Fuellen von Roehrchenelektrodenplatten fuer Bleiakkumulatoren

    Energy Technology Data Exchange (ETDEWEB)

    Barth, P.U.; Kubis, C.; Weber, H.J.; Wiepen, R.

    1984-11-22

    The device applies the vibration principle and according to the invention it uses a filling cassette for accommodating tubular electrode plates. The filling cassette has a filling funnel and is suspended with its vibration drive by springs. The vibration drive consists either of two out-of-balance motors, which are rigidly connected to the lower frame of the cassette, and have opposite directions of rotation, or of one out-of-balance motor, which is connected to a joint below the frame of the cassette.

  14. Device for filling tubular electrode plates for lead batteries. [German patent

    Energy Technology Data Exchange (ETDEWEB)

    Barth, P.U.; Kubis, C.; Weber, H.J.; Wiepen, R.

    1979-02-01

    The device applies the vibration principle and according to the invention it uses a filling cassette for accommodating tubular electrode plates. The filling cassette has a filling funnel and is suspended with its vibration drive by springs. The vibration drive consists either of two out-of-balance motors, which are rigidly connected to the lower frame of the cassette, and have opposite directions of rotation, or of one out-of-balance motor, which is connected to a joint below the frame of the cassette.

  15. Rheological characterisation and printing performance of Sn/Ag/Cu solder pastes

    International Nuclear Information System (INIS)

    Durairaj, R.; Ramesh, S.; Mallik, S.; Seman, A.; Ekere, N.

    2009-01-01

    Lead-free solder paste printing process accounts for majority of the assembly defects in the electronic manufacturing industry. The study investigates rheological behaviour and stencil printing performance of the lead-free solder pastes (Sn/Ag/Cu). Oscillatory stress sweep test was carried out to study the visco-elastic behaviour of the lead-free solder pastes. The visco-elastic behaviour of the paste encompasses solid and liquid characteristic of the paste, which could be used to study the flow behaviour experienced by the pastes during the stencil printing process. From this study, it was found that the solid characteristics (G') is higher than the liquid characteristic (G'') for the pastes material. In addition, the results from the study showed that the solder paste with a large G' = G'' has a higher cohesiveness resulting in poor withdrawal of the paste during the stencil printing process. The phase angles (δ) was used to correlate the quality of the dense suspensions to the formulation of solder paste materials. This study has revealed the value of having a rheological measurement for explaining and characterising solder pastes for stencil printing. As the demand for lead free pastes increases rheological measurements can assist with the formulation or development of new pastes.

  16. An in situ generated carbon as integrated conductive additive for hierarchical negative plate of lead-acid battery

    Science.gov (United States)

    Saravanan, M.; Ganesan, M.; Ambalavanan, S.

    2014-04-01

    In this work, we report an in situ generated carbon from sugar as additive in the Negative Active Mass (NAM) which enhances the charge-discharge characteristics of the lead-acid cells. In situ formed sugar derived carbon (SDC) with leady oxide (LO) provides a conductive network and excellent protection against NAM irreversible lead sulfation. The effect of SDC and carbon black (CB) added negative plates are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), galvanostatic charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. The results show that subtle changes in the addition of carbon to NAM led to subsequent changes on the performance during partial-state-of-charge (PSoC) operations in lead-acid cells. Furthermore, SDC added cells exhibit remarkable improvement in the rate capability, active material utilization, cycle performance and charge acceptance compared to that of the conventional CB added cells. The impact of SDC with LO at various synthesis conditions on the electrochemical performance of the negative plate is studied systematically.

  17. Spectroscopic investigation of oxidized solder surfaces

    International Nuclear Information System (INIS)

    Song, Jenn-Ming; Chang-Chien, Yu-Chien; Huang, Bo-Chang; Chen, Wei-Ting; Shie, Chi-Rung; Hsu, Chuang-Yao

    2011-01-01

    Highlights: → UV-visible spectroscopy is successfully used to evaluate the degree of discoloring of solders. → The surface oxides of solders can also be identified by UV-visible absorption spectra. → The discoloration of solder surface can be correlated with optical characterization of oxides. → A strategy against discoloring by alloying was also suggested. - Abstract: For further understanding of the discoloration of solder surfaces due to oxidation during the assembly and operation of electronic devices, UV-vis and X-ray photoelectron spectroscopic analyses were applied to evaluate the degree of discoloring and identify the surface oxides. The decrease in reflectance of the oxidized solder surface is related to SnO whose absorption band is located within the visible region. A trace of P can effectively depress the discoloration of solders under both solid and semi-solid states through the suppression of SnO.

  18. Soldering Characteristics and Mechanical Properties of Sn-1.0Ag-0.5Cu Solder with Minor Aluminum Addition

    Directory of Open Access Journals (Sweden)

    Yee Mei Leong

    2016-06-01

    Full Text Available Driven by the trends towards miniaturization in lead free electronic products, researchers are putting immense efforts to improve the properties and reliabilities of Sn based solders. Recently, much interest has been shown on low silver (Ag content solder SAC105 (Sn-1.0Ag-0.5Cu because of economic reasons and improvement of impact resistance as compared to SAC305 (Sn-3.0Ag-0.5Cu. The present work investigates the effect of minor aluminum (Al addition (0.1–0.5 wt.% to SAC105 on the interfacial structure between solder and copper substrate during reflow. The addition of minor Al promoted formation of small, equiaxed Cu-Al particle, which are identified as Cu3Al2. Cu3Al2 resided at the near surface/edges of the solder and exhibited higher hardness and modulus. Results show that the minor addition of Al does not alter the morphology of the interfacial intermetallic compounds, but they substantially suppress the growth of the interfacial Cu6Sn5 intermetallic compound (IMC after reflow. During isothermal aging, minor alloying Al has reduced the thickness of interfacial Cu6Sn5 IMC but has no significant effect on the thickness of Cu3Sn. It is suggested that of atoms of Al exert their influence by hindering the flow of reacting species at the interface.

  19. Soldering Characteristics and Mechanical Properties of Sn-1.0Ag-0.5Cu Solder with Minor Aluminum Addition

    Science.gov (United States)

    Leong, Yee Mei; Haseeb, A.S.M.A.

    2016-01-01

    Driven by the trends towards miniaturization in lead free electronic products, researchers are putting immense efforts to improve the properties and reliabilities of Sn based solders. Recently, much interest has been shown on low silver (Ag) content solder SAC105 (Sn-1.0Ag-0.5Cu) because of economic reasons and improvement of impact resistance as compared to SAC305 (Sn-3.0Ag-0.5Cu. The present work investigates the effect of minor aluminum (Al) addition (0.1–0.5 wt.%) to SAC105 on the interfacial structure between solder and copper substrate during reflow. The addition of minor Al promoted formation of small, equiaxed Cu-Al particle, which are identified as Cu3Al2. Cu3Al2 resided at the near surface/edges of the solder and exhibited higher hardness and modulus. Results show that the minor addition of Al does not alter the morphology of the interfacial intermetallic compounds, but they substantially suppress the growth of the interfacial Cu6Sn5 intermetallic compound (IMC) after reflow. During isothermal aging, minor alloying Al has reduced the thickness of interfacial Cu6Sn5 IMC but has no significant effect on the thickness of Cu3Sn. It is suggested that of atoms of Al exert their influence by hindering the flow of reacting species at the interface. PMID:28773645

  20. Soldering of Mg Joints Using Zn-Al Solders

    Science.gov (United States)

    Gancarz, Tomasz; Berent, Katarzyna; Skuza, Wojciech; Janik, Katarzyna

    2018-04-01

    Magnesium has applications in the automotive and aerospace industries that can significantly contribute to greater fuel economy and environmental conservation. The Mg alloys used in the automotive industry could reduce mass by up to 70 pct, providing energy savings. However, alongside the advantages there are limitations and technological barriers to use Mg alloys. One of the advantages concerns phenomena occurring at the interface when joining materials investigated in this study, in regard to the effect of temperature and soldering time for pure Mg joints. Eutectic Zn-Al and Zn-Al alloys with 0.05 (wt pct) Li and 0.2 (wt pct) Na were used in the soldering process. The process was performed for 3, 5, and 8 minutes of contact, at temperatures of 425 °C, 450 °C, 475 °C, and 500 °C. Selected, solidified solder-substrate couples were cross-sectioned, and their interfacial microstructures were investigated by scanning electron microscopy. The experiment was designed to demonstrate the effect of time, temperature, and the addition of Li and Na on the kinetics of the dissolving Mg substrate. The addition of Li and Na to eutectic Zn-Al caused to improve mechanical properties. Higher temperatures led to reduced joint strength, which is caused by increased interfacial reaction.

  1. Wall-slip effects in SnAgCu solder pastes used in electronics assembly applications

    International Nuclear Information System (INIS)

    Mallik, S.; Ekere, N.N.; Durairaj, R.; Marks, A.E.; Seman, A.

    2009-01-01

    Solder paste is the most important strategic bonding material used in the assembly of surface mount components in electronics manufacturing. As the trend towards miniaturisation of electronic products continues, there is an increasing demand for better understanding of the flow and deformation that is, the rheological behaviour of solder paste formulations. Wall slip plays an important role in characterising the flow behaviour of solder paste materials. The problem of wall slip arises due to the various attractive and repulsive forces acting between the solder particles and the walls of the measuring geometry. These interactions could lead to the presence of a thin solvent layer adjacent to the wall, which gives rise to slippage. In rheological measurements, slip effects can generally be avoided by using roughened surfaces for measuring geometries. In this paper, a novel technique is developed to study the effect of wall slip in the rheological measurements of lead-free solder paste. The viscosity and oscillatory data obtained for three different solder paste samples (from measuring geometries of different surface roughness) have been analysed and compared. In viscosity measurements, slip effects were dominant at low shear rates and the use of serrated surfaces was found to be quite effective in minimizing slip effects. Oscillatory measurements were also affected by roughening the surfaces of measuring geometries.

  2. Plating laboratory

    International Nuclear Information System (INIS)

    Seamster, A.G.; Weitkamp, W.G.

    1984-01-01

    The lead plating of the prototype resonator has been conducted entirely in the plating laboratory at SUNY Stony Brook. Because of the considerable cost and inconvenience in transporting personnel and materials to and from Stony Brook, it is clearly impractical to plate all the resonators there. Furthermore, the high-beta resonator cannot be accommodated at Stony Brook without modifying the set up there. Consequently the authors are constructing a plating lab in-house

  3. Nano-soldering to single atomic layer

    Science.gov (United States)

    Girit, Caglar O [Berkeley, CA; Zettl, Alexander K [Kensington, CA

    2011-10-11

    A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

  4. Safer Soldering Guidelines and Instructional Resources

    Science.gov (United States)

    Love, Tyler S.; Tomlinson, Joel

    2018-01-01

    Soldering is a useful and necessary process for many classroom, makerspace, Fab Lab, technology and engineering lab, and science lab activities. As described in this article, soldering can pose many safety risks without proper engineering controls, standard operating procedures, and direct instructor supervision. There are many safety hazards…

  5. Features of soldering of molybdenum a lols

    International Nuclear Information System (INIS)

    Grishin, V.L.; Rybkin, B.V.; Cherkasov, A.F.

    1980-01-01

    Soldering features of complex-alloy molybdenum alloys were investigated in comparison with alloys based on solid solutions. Soldering features of heterogeneous molybdenum base alloys were investigated using samples of 0.5-1.O mm sheets with the strain of about 95% made of ingots which had been smelted in arc vacuum furnaces. The soldering of samples was carried out in 5x1O -5 mm Hg vacuum using different sources of heating: radiation, electron-ray and contact. It was shown that heat-resisting soldered joints of heterogeneous molybdenum alloys could be produced using zirconium and niobium base solders containing the most effective hardeners of the parent material (titanum, vanadium, tantalum, molybdenum, tungsten). To preserve high mechanical properties of heterogeneous alloys it was expedient to use for welding local heating sources which permitted to decrease considerably temperature- time conditions of the process

  6. Development of Streamwise Counter-Rotating Vortices in Flat Plate Boundary Layer Pre-set by Leading Edge Patterns

    KAUST Repository

    Hasheminejad, S.M.

    2017-04-03

    Development of streamwise counter-rotating vortices induced by leading edge patterns with different pattern shape is investigated using hot-wire anemometry in the boundary layer of a flat plate. A triangular, sinusoidal and notched patterns with the same pattern wavelength λ of 15mm and the same pattern amplitude A of 7.5mm were examined for free-stream velocity of 3m/s. The results show a good agreement with earlier studies. The inflection point on the velocity profile downstream of the trough of the patterns at the beginning of the vortex formation indicates that the vortices non-linearly propagate downstream. An additional vortex structure was also observed between the troughs of the notched pattern.

  7. A Probabilistic Approach to Predict Thermal Fatigue Life for Ball Grid Array Solder Joints

    Science.gov (United States)

    Wei, Helin; Wang, Kuisheng

    2011-11-01

    Numerous studies of the reliability of solder joints have been performed. Most life prediction models are limited to a deterministic approach. However, manufacturing induces uncertainty in the geometry parameters of solder joints, and the environmental temperature varies widely due to end-user diversity, creating uncertainties in the reliability of solder joints. In this study, a methodology for accounting for variation in the lifetime prediction for lead-free solder joints of ball grid array packages (PBGA) is demonstrated. The key aspects of the solder joint parameters and the cyclic temperature range related to reliability are involved. Probabilistic solutions of the inelastic strain range and thermal fatigue life based on the Engelmaier model are developed to determine the probability of solder joint failure. The results indicate that the standard deviation increases significantly when more random variations are involved. Using the probabilistic method, the influence of each variable on the thermal fatigue life is quantified. This information can be used to optimize product design and process validation acceptance criteria. The probabilistic approach creates the opportunity to identify the root causes of failed samples from product fatigue tests and field returns. The method can be applied to better understand how variation affects parameters of interest in an electronic package design with area array interconnections.

  8. The influence of silver content on structure and properties of Sn–Bi–Ag solder and Cu/solder/Cu joints

    Energy Technology Data Exchange (ETDEWEB)

    Šebo, P. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Švec, P. Sr., E-mail: Peter.Svec@savba.sk [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janičkovič, D.; Illeková, E. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Zemánková, M. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine); Sidorov, V. [Ural State Pedagogical University, Cosmonavtov 26, 620017 Ekaterinburg (Russian Federation); Švec, P. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia)

    2013-06-01

    The effect of silver content on structure and properties of Sn{sub 100−x}Bi{sub 10}Ag{sub x} (x=3–10 at%) lead-free solder and Cu–solder–Cu joints was investigated. The microstructure of the solder in both bulk and rapidly solidified ribbon forms was analyzed by scanning electron microscopy (SEM) and X-ray diffraction. The peculiarities in melting kinetic, studied by differential scanning calorimetry (DSC), and silver influence on it are described and discussed. The wetting of a copper substrate was examined by the sessile drop method in the temperature range of 553–673 K in air and deoxidizing gas (N{sub 2}+10%H{sub 2}) at atmospheric pressure. Cu–solder–Cu joints were also prepared in both atmospheres, and their shear strength was measured by the push-off method. The produced solders consisted of tin, bismuth and Ag{sub 3}Sn phases. The product of the interaction between the solder and the copper substrate consists of two phases: Cu{sub 3}Sn, which is adjacent to the substrate, and a Cu{sub 6}Sn{sub 5} phase. The wetting angle in air increased slightly as the silver concentration in the solder increased. Wetting of the copper substrate in N{sub 2}+10H{sub 2} gas shows the opposite tendency: the wetting angle slightly decreased as the silver content in the solder increased. The shear strength of the joints prepared in air (using flux) tends to decrease with increasing production temperature and increasing silver content in the solder. The equivalent decrease in the shear strength of the joints prepared in N{sub 2}+10H{sub 2} is more apparent.

  9. Photothermal effects of laser tissue soldering

    International Nuclear Information System (INIS)

    McNally, K.M.; Sorg, B.S.; Welch, A.J.; Dawes, J.M.; Owen, E.R.

    1999-01-01

    Low-strength anastomoses and thermal damage of tissue are major concerns in laser tissue welding techniques where laser energy is used to induce thermal changes in the molecular structure of the tissues being joined, hence allowing them to bond together. Laser tissue soldering, on the other hand, is a bonding technique in which a protein solder is applied to the tissue surfaces to be joined, and laser energy is used to bond the solder to the tissue surfaces. The addition of protein solders to augment tissue repair procedures significantly reduces the problems of low strength and thermal damage associated with laser tissue welding techniques. Investigations were conducted to determine optimal solder and laser parameters for tissue repair in terms of tensile strength, temperature rise and damage and the microscopic nature of the bonds formed. An in vitro study was performed using an 808 nm diode laser in conjunction with indocyanine green (ICG)-doped albumin protein solders to repair bovine aorta specimens. Liquid and solid protein solders prepared from 25% and 60% bovine serum albumin (BSA), respectively, were compared. The efficacy of temperature feedback control in enhancing the soldering process was also investigated. Increasing the BSA concentration from 25% to 60% greatly increased the tensile strength of the repairs. A reduction in dye concentration from 2.5mgml -1 to 0.25mgml -1 was also found to result in an increase in tensile strength. Increasing the laser irradiance and thus surface temperature resulted in an increased severity of histological injury. Thermal denaturation of tissue collagen and necrosis of the intimal layer smooth muscle cells increased laterally and in depth with higher temperatures. The strongest repairs were produced with an irradiance of 6.4Wcm -2 using a solid protein solder composed of 60% BSA and 0.25mgml -1 ICG. Using this combination of laser and solder parameters, surface temperatures were observed to reach 85±5 deg. C with a

  10. Solderability study of RABiTS-based YBCO coated conductors

    International Nuclear Information System (INIS)

    Zhang Yifei; Duckworth, Robert C.; Ha, Tam T.; Gouge, Michael J.

    2011-01-01

    Study examines the implication of solder and flux selection in YBCO splice joints. Focus is on commercially available RABiTS-based YBCO coated conductors. Solderability varied with solder and flux for three different stabilizations tested. Resistivity of stabilizer was dominant factor in splice joint resistance. Solder materials affected splice joint resistance when solderability was poor. The solderability of commercially available YBa 2 Cu 3 O 7-x (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and with two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.

  11. Optimal parameters for laser tissue soldering

    Science.gov (United States)

    McNally-Heintzelman, Karen M.; Sorg, Brian S.; Chan, Eric K.; Welch, Ashley J.; Dawes, Judith M.; Owen, Earl R.

    1998-07-01

    Variations in laser irradiance, exposure time, solder composition, chromophore type and concentration have led to inconsistencies in published results of laser-solder repair of tissue. To determine optimal parameters for laser tissue soldering, an in vitro study was performed using an 808-nm diode laser in conjunction with an indocyanine green (ICG)- doped albumin protein solder to weld bovine aorta specimens. Liquid and solid protein solders prepared from 25% and 60% bovine serum albumin (BSA), respectively, were compared. The effects of laser irradiance and exposure time on tensile strength of the weld and temperature rise as well as the effect of hydration on bond stability were investigated. Optimum irradiance and exposure times were identified for each solder type. Increasing the BSA concentration from 25% to 60% greatly increased the tensile strength of the weld. A reduction in dye concentration from 2.5 mg/ml to 0.25 mg/ml was also found to result in an increase in tensile strength. The strongest welds were produced with an irradiance of 6.4 W/cm2 for 50 s using a solid protein solder composed of 60% BSA and 0.25 mg/ml ICG. Steady-state solder surface temperatures were observed to reach 85 plus or minus 5 degrees Celsius with a temperature gradient across the solid protein solder strips of between 15 and 20 degrees Celsius. Finally, tensile strength was observed to decrease significantly (20 to 25%) after the first hour of hydration in phosphate-buffered saline. No appreciable change was observed in the strength of the tissue bonds with further hydration.

  12. Thermomechanical Behavior of Monolithic SN-AG-CU Solder and Copper Fiber Reinforced Solders

    National Research Council Canada - National Science Library

    Reuse, Rolando

    2005-01-01

    .... The thermomechanical cycling in the solder causes numerous reliability challenges, mostly because of the mismatch of the coefficient of thermal expansion between the silicon chip and the substrate...

  13. Lead - nutritional considerations

    Science.gov (United States)

    ... billion people had toxic (poisonous) blood lead levels. Food Sources Lead can be found in canned goods if there is lead solder in the ... to bottled water for drinking and cooking. Avoid canned goods from foreign ... cans goes into effect. If imported wine containers have a lead foil ...

  14. Tests of beta = 0.1 and development of beta = 0.2 lead plated quarter wave resonators

    International Nuclear Information System (INIS)

    Storm, D.W.; Goliak, T.; Seamster, A.G.; Brennan, J.M.; Coughlin, R.; Ben-Zvi, I.

    1984-01-01

    A prototype lead plated copper quarter wave resonator has been built for the University of Washington Superconducting Booster. The design of this resonator followed that of Brennan and Ben-Zvi. The drift tubes were built in Israel, and are identical to those built for the Weizmann Institute quarter wave resonators. The other dimensions of the resonator were similar to those of the Weizmann Institute unit, except the radius of the outer conductor was increased by one cm and the resonator was made slightly longer to reduce the frequency from about 160 to 150 MHz. This extra one cm in radius was used to increase the gap between the center and side drift tubes, so that the UW resonator had 5 cm gaps while both the design discussed by Brennan and Ben-Zvi and the resonators they built had 4 cm gaps. Both our resonator and the one they built had side drift tubes extending 2 cm radially inward, while the one discussed in Ref. 1 had 3 cm drift tubes. We anticipated that this increased gap would reduce the surface field at the center drift tube; however upon further consideration, it seems unlikely that it had much effect. The larger gap does decrease the gap transit time factor (by only about 2%) and increases the optimum velocity by about 17%. In addition, the larger diameter gives a larger stored energy but also, for the same average field, 12.5% more energy gain

  15. Thermomechanical fatigue life prediction for several solders

    Science.gov (United States)

    Wen, Shengmin

    Since solder connections operate at high homologous temperature, solders are high temperature materials. This feature makes their mechanical behavior and fatigue phenomena unique. Based on experimental findings, a physical damage mechanism is introduced for solders. The mechanism views the damage process as a series of independent local damage events characterized by the failure of individual grains, while the structural damage is the eventual percolation result of such local events. Fine's dislocation energy density concept and Mura's microcrack initiation theory are adopted to derive the fatigue formula for an individual grain. A physical damage metric is introduced to describe the material with damage. A unified creep and plasticity constitutive model is adopted to simulate the mechanical behavior of solders. The model is cast into a continuum damage mechanics framework to simulate material with damage. The model gives good agreement with the experimental results of 96.5Pb-3.5Sn and 96.5Sn-3.5Ag solders under uniaxial strain-controlled cyclic loading. The model is convenient for implementation into commercial computational packages. Also presented is a fatigue theory with its failure criterion for solders based on physical damage mechanism. By introducing grain orientation into the fatigue formula, an m-N curve (m is Schmid factor) at constant loading condition is suggested for fatigue of grains with different orientations. A solder structure is defined as fatigued when the damage metric reaches a critical threshold, since at this threshold the failed grains may form a cluster and percolate through the structure according to percolation theory. Fatigue data of 96.5Pb-3.5Sn solder bulk specimens under various uniaxial tension tests were analyzed. Results show that the theory gives consistent predictions under broad conditions, while inelastic strain theory does not. The theory is anisotropic with no size limitation to its application, which could be suitable for

  16. Improvement of the auto wire feeder machine in a de-soldering process

    Directory of Open Access Journals (Sweden)

    Niramon Nonkhukhetkhong

    2016-10-01

    Full Text Available This paper presents the methodology of the de-soldering process for rework of disk drive Head Stack Assembly (HSA units. The auto wire feeder is a machine that generates Tin (Sn on the product. This machine was determined to be one of the major sources of excess Sn on the HSA. The defect rate due to excess Sn is more than 30%, which leads to increased processing time and cost to perform additional cleaning steps. From process analysis, the major causes of excess Sn are as follows: 1 The machine cannot cut the wire all the way into the flux core area; 2 The sizes and types of soldering irons are not appropriate for the unit parts; and, 3 There are variations introduced into the de-soldering process by the workforce. This paper proposes a methodology to address all three of these causes. First, the auto wire feeder machine in the de-solder process will be adjusted in order to cut wires into flux core. Second, the types of equipment and material used in de-soldering will be optimized. Finally, a new standard method for operators, which can be controlled more easily, will be developed in order to reduce defects due to workforce related variation. After these process controls and machine adjustments were implemented, the overall Sn related problems were significantly improved. Sn contamination was reduced by 41% and cycle time was reduced by an average of 15 seconds.

  17. The Effect of Reflow on Wettability of Sn 96.5 Ag 3 Cu 0.5 Solder

    Directory of Open Access Journals (Sweden)

    Zoltán Weltsch

    2012-11-01

    Full Text Available Surface conditions on Printed Circuit Board (PCB final finishes have an important impact on the wetting behaviour with lead-free solder. The improvement of wettability in liquid Sn 96.5 Ag 3 Cu 0.5 Solder alloy on PCB substrate was measured with a sessile drop method at 523 K temperature. Wetting properties was determined in normal atmospheric air and inert atmosphere. The wetting angles increasing with the number of reflows both atmosphere. The effect of the atmosphere has a huge importance of the oxidation which manifests itself of the measured wetting angles. One of the most important factors to the wetting properties is the amount of oxygen in the soldering atmosphere. Using the inert atmosphere is crucial to Pb-free solders, particularly after reflows.

  18. Negative plates for dry-charged lead storage batteries. [higher charging capacity when impregnated with tannin solution

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, V; Malikova, V; Weber, H

    1970-09-15

    Impregnation of negative plates with acid solutions of sulfomethylated tannins was found to improve the charging properties at low temperatures. Methods for synthesizing tannins are described. Charging capacity at 0/sup 0/ was 7.3A. (RWR)

  19. A review of typical thermal fatigue failure models for solder joints of electronic components

    Science.gov (United States)

    Li, Xiaoyan; Sun, Ruifeng; Wang, Yongdong

    2017-09-01

    For electronic components, cyclic plastic strain makes it easier to accumulate fatigue damage than elastic strain. When the solder joints undertake thermal expansion or cold contraction, different thermal strain of the electronic component and its corresponding substrate is caused by the different coefficient of thermal expansion of the electronic component and its corresponding substrate, leading to the phenomenon of stress concentration. So repeatedly, cracks began to sprout and gradually extend [1]. In this paper, the typical thermal fatigue failure models of solder joints of electronic components are classified and the methods of obtaining the parameters in the model are summarized based on domestic and foreign literature research.

  20. Instantaneous fluxless bonding of Au with Pb-Sn solder in ambient atmosphere

    International Nuclear Information System (INIS)

    Lee, T.K.; Zhang, Sam; Wong, C.C.; Tan, A.C.

    2005-01-01

    A fluxless bonding technique has been developed as a method of flip-chip bonding for microelectronic packaging. The fluxless bonding technique can be achieved instantaneously in an ambient environment between metallic stud bumps and predefined molten solder. This paper describes the mechanics of the bonding action and verifies the effectiveness of this bonding method through wetting balance tests and scanning electron microscope and energy dispersive x-ray analysis. This technique has been demonstrated by using a gold stud bump to break the tin oxide layer over molten solder. This allows for a fast, solid liquid interdiffusion between gold (Au) and the fresh molten eutectic lead-tin (Pb-Sn) solder for joint formation during solidification. This bonding method has been successfully tested with 130-μm-pitch flip-chip bond pads on a joint-in-via flex substrate architecture

  1. Pretinning Nickel-Plated Wire Shields

    Science.gov (United States)

    Igawa, J. A.

    1985-01-01

    Nickel-plated copper shielding for wires pretinned for subsequent soldering with help of activated rosin flux. Shield cut at point 0.25 to 0.375 in. (6 to 10 mm) from cut end of outer jacket. Loosened end of shield straightened and pulled toward cut end. Insulation of inner wires kept intact during pretinning.

  2. High temperature soldering of graphite

    International Nuclear Information System (INIS)

    Anikin, L.T.; Kravetskij, G.A.; Dergunova, V.S.

    1977-01-01

    The effect is studied of the brazing temperature on the strength of the brazed joint of graphite materials. In one case, iron and nickel are used as solder, and in another, molybdenum. The contact heating of the iron and nickel with the graphite has been studied in the temperature range of 1400-2400 ged C, and molybdenum, 2200-2600 deg C. The quality of the joints has been judged by the tensile strength at temperatures of 2500-2800 deg C and by the microstructure. An investigation into the kinetics of carbon dissolution in molten iron has shown that the failure of the graphite in contact with the iron melt is due to the incorporation of iron atoms in the interbase planes. The strength of a joint formed with the participation of the vapour-gas phase is 2.5 times higher than that of a joint obtained by graphite recrystallization through the carbon-containing metal melt. The critical temperatures are determined of graphite brazing with nickel, iron, and molybdenum interlayers, which sharply increase the strength of the brazed joint as a result of the formation of a vapour-gas phase and deposition of fine-crystal carbon

  3. Efforts to Develop a 300°C Solder

    Energy Technology Data Exchange (ETDEWEB)

    Norann, Randy A [Perma Works LLC

    2015-01-25

    This paper covers the efforts made to find a 300°C electrical solder solution for geothermal well monitoring and logging tools by Perma Works LLC. This paper covers: why a high temperature solder is needed, what makes for a good solder, testing flux, testing conductive epoxy and testing intermetallic bonds. Future areas of research are suggested.

  4. Studies of the pulse charge of lead-acid batteries for PV applications. Part I. Factors influencing the mechanism of the pulse charge of the positive plate

    Energy Technology Data Exchange (ETDEWEB)

    Kirchev, A.; Perrin, M.; Lemaire, E.; Karoui, F.; Mattera, F. [Commissariat de l' Energie Atomique, Institut National de l' Energie Solaire, INES-RDI, Parc Technologique de Savoie Technolac, 50 Avenue du Lac Leman, 73377 Le Bourget du Lac Cedex (France)

    2008-02-15

    The mechanism of the positive plate charge in pulse regime was studied in model lead-acid cells with one positive and two negative plates (8 Ah each) and Ag/Ag{sub 2}SO{sub 4} reference electrodes. The results showed that the evolution of the electrode potential is much slower on the positive plate than on the negative plate. Regardless of this fact, the calculated capacitive current of charge and self-discharge of the electrochemical double layer (EDL) during the 'ON' and 'OFF' half-periods of the pulse current square waves is comparable with the charge current amplitude. The result is due to the high values of the EDL on the surface of the lead dioxide active material. The influence of different factors like state of charge, state of health, pulse frequency, current amplitude and open circuit stay before the polarization was discussed. The previously determined optimal frequency of 1 Hz was associated with a maximum in the average double layer current on frequency dependence. The average double layer current is also maximal at SOC between 75 and 100%. The exchange of the constant current polarization with pulse polarization does not change substantially the mechanism and the overvoltage of the oxygen evolution reaction on the positive plate. The mechanism of the self-discharge of the EDL was also estimated analyzing long-time PPP transients (up to 2 h). It was found that when the PPP is lower than 1.2 V the preferred mechanism of EDL self-discharge is by coupling with the lead sulphate oxidation reaction. At higher values of PPP the EDL self-discharge happens via oxygen evolution. The high faradic efficiency of the pulse charge is due to the chemical oxidation of the Pb(II) ions by the O atoms and OH radicals formed at the oxygen evolution both during the 'ON' and 'OFF' periods. (author)

  5. Commentary: Photothermal effects of laser tissue soldering

    International Nuclear Information System (INIS)

    Menovsky, T.; Beek, J.F.; Gemert, M.J.C. van

    1999-01-01

    Full text: Laser tissue welding is the process of using laser energy to join tissues without sutures or with a reduced number of sutures. Recently, diode lasers have been added to the list of fusion lasers (Lewis and Uribe 1993, Reali et al 1993). Typically, for tissue welding, deep penetrating diode lasers emitting at 800-810 nm are used, in combination with a strong absorbing protein solder containing the dye indocyanine green. Indocyanine green has a maximum absorption coefficient at 805 nm and binds preferentially with proteins (Sauda et al 1986). The greatest advantage of diode lasers is their compact size, easy use and low cost. In this issue of Physics in Medicine and Biology (pp 983-1002, 'Photothermal effects of laser tissue soldering'), in an in vitro study, McNally et al investigate the optimal laser settings and welding temperatures in relation to the tensile strength and thermal damage of bovine aorta specimens. An interesting statement in their introduction is that the low strength of laser produced anastomoses can lead to aneurysm formation. The increased chance of aneurysm formation may merely be due to the thermal effect of the laser on the vascular wall, especially on the adventitia and media layers, which become necrotic after thermal injury. Subsequent haemodynamic stress exerted on a damaged vascular wall is a significant contributing factor for aneurysmal initiation. Also interesting is the remark that 'by the application of wavelength-specific chromophores in tissue welding ... the requirement for precise focusing and aiming of the laser beam may be removed'. Though perhaps not yet fully justified, this statement, if true, would facilitate surgical procedures. While the experiments are conducted in a proper manner, the use of bovine aorta specimens, which were stored at -70 deg. C and subsequently thawed for the tissue welding experiments, may not be the most appropriate for studying tissue effects or tensile strength measurements, as the

  6. THE POSSIBILITY OF USING LASER-ULTRASOUND TO MONITOR THE QUALITY SOLDERED CONNECTIONS CHAMBERS OF LIQUID ROCKET ENGINES

    Directory of Open Access Journals (Sweden)

    N. V. Astredinova

    2014-01-01

    Full Text Available During the manufacturing process to the design of modern liquid rocket engines are presented important requirements, such as minimum weight, maximum stiffness and strength of nodes, maximum service life in operation, high reliability and quality of soldered and welded seams. Due to the high quality requirements soldered connections and the specific design of the nozzle, it became necessary in the development and testing of a new non-conventional non-destructive testing method – laser-ultrasound diagnosis. In accordance with regulatory guidelines, quality control soldered connections is allowed to use an acoustic kind of control methods of the reflected light, transmitted light, resonant, free vibration and acoustic emission. Attempts to use traditional methods of non-destructive testing did not lead to positive results. This is due primarily to the size of typical solder joint defects, as well as the structural features of the rocket engine, the data structure is not controllable. In connection with this, a new method that provides quality control soldered connections cameras LRE based on the thermo generation of ultrasound. Methods of ultrasonic flaw detection of photoacoustic effect, in most cases, have a number of advantages over methods that use standard (traditional piezo transducers. In the course of studies have found that the sensitivity of the laser-ultrasonic method and flaw detector UDL-2M can detect lack of adhesion in the solder joints on the upper edges of the nozzle in the sub-header area of the site.

  7. Development of high melting point, environmentally friendly solders, using the calphad approach

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2008-01-01

    An attempt has been made using the CALPHAD approach via Thermo-Calc to explore the various possible chemical compositions that adhere to the melting criterion i.e. 270-350 degrees C, required to replace the traditionally used high lead content solders for first level packaging applications. Vario...... tension have also been considered. Special focus has been given to toxicity related issues since the main ideology of looking for an alternative to high lead containing solders is not related to technical issues but due to environmental concerns.......An attempt has been made using the CALPHAD approach via Thermo-Calc to explore the various possible chemical compositions that adhere to the melting criterion i.e. 270-350 degrees C, required to replace the traditionally used high lead content solders for first level packaging applications. Various...... of promising solder alloy candidates. The ternary combinations that satisfied the primary solidification requirement were scrutinized taking into account the commercial interests i.e. availability, cost-effectiveness, recyclability and toxicity issues. Technical issues like manufacturability and surface...

  8. The fabrication and characterization of an ex situ plated lead film electrode prepared with the use of a reversibly deposited mediator metal

    International Nuclear Information System (INIS)

    Tyszczuk, Katarzyna

    2011-01-01

    Research highlights: → The lead film electrode prepared with use of the mediator metal was elaborated. → The lead-based sensors were characterized by optical and voltammetric methods. → The adsorptive system of folic acid was employed to investigate a new electrode. → The application of the mediator metal improved properties of a lead film electrode. - Abstract: In this paper an ex situ plated lead film electrode prepared with use of the mediator metal (Zn) was elaborated. The electrochemical method for lead film formation is based on a co-deposition of a metal of interest (Pb) with a reversibly deposited mediator metal (Zn) and then on an oxidation of zinc and further deposition of lead by the appropriate potential. This serves to increase the density of islands of lead atoms, promoting lead film growth. The lead-based sensors were characterized by optical method (atomic force microscopy (AFM)) and as well as cyclic, linear sweep and square wave voltammetry. The adsorptive system of folic acid was employed to investigate the electrochemical characteristics a novel type of lead film electrode. Well-formed stripping peaks and a linear dependence of the stripping current on the folic acid concentration were observed on the lead film electrode prepared with use of the mediator metal while comparative measurements attempted with the lead film electrode prepared without use of the mediator metal were unsuccessful.

  9. Mechanism of action of electrochemically active carbons on the processes that take place at the negative plates of lead-acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Pavlov, D.; Rogachev, T.; Nikolov, P.; Petkova, G. [Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, bl. 10, Sofia 1113 (Bulgaria)

    2009-06-01

    It is known that negative plates of lead-acid batteries have low charge acceptance when cycled at high rates and progressively accumulate lead sulphate on high-rate partial-state-of-charge (HRPSoC) operation in hybrid-electric vehicle (HEV) applications. Addition of some carbon or graphite forms to the negative paste mix improves the charge efficiency and slows down sulfation of the negative plates. The present investigation aims to elucidate the contribution of electrochemically active carbon (EAC) additives to the mechanism of the electrochemical reactions of charge of the negative plates. Test cells are assembled with four types of EAC added to the negative paste mix in five different concentrations. Through analysis of the structure of NAM (including specific surface and pore radius measurements) and of the electrochemical parameters of the test cells on HRPSoC cycling, it is established that the electrochemical reaction of charge Pb{sup 2+} + 2e{sup -} {yields} Pb proceeds at 300-400 mV lower over-potentials on negative plates doped with EAC additives as compared to the charge potentials of cells with no carbon additives. Hence, electrochemically active carbons have a highly catalytic effect on the charge reaction and are directly involved in it. Consequently, the reversibility of the charge/discharge processes is improved, which eventually leads to longer battery cycle life. Thus, charging of the negative plates proceeds via a parallel mechanism on the surfaces of both Pb and EAC particles, at a higher rate on the EAC phase. Cells with EAC in NAM have the longest cycle life when their NAM specific surface is up to 4 m{sup 2} g{sup -1} against 0.5 m{sup 2} g{sup -1} for the lead surface. The proposed parallel mechanism of charge is verified experimentally on model Pb/EAC/PbSO{sub 4} and Pb/EAC electrodes. During the charge and discharge cycles of the HRPSoC test, the EAC particles are involved in dynamic adsorption/desorption on the lead sulfate and lead

  10. A Hodge dual for soldered bundles

    International Nuclear Information System (INIS)

    Lucas, Tiago Gribl; Pereira, J G

    2009-01-01

    In order to account for all possible contractions allowed by the presence of the solder form, a generalized Hodge dual is defined for the case of soldered bundles. Although for curvature the generalized dual coincides with the usual one, for torsion it gives a completely new dual definition. Starting from the standard form of a gauge Lagrangian for the translation group, the generalized Hodge dual yields precisely the Lagrangian of the teleparallel equivalent of general relativity, and consequently also the Einstein-Hilbert Lagrangian of general relativity

  11. Visual detection of defects in solder joints

    Science.gov (United States)

    Blaignan, V. B.; Bourbakis, Nikolaos G.; Moghaddamzadeh, Ali; Yfantis, Evangelos A.

    1995-03-01

    The automatic, real-time visual acquisition and inspection of VLSI boards requires the use of machine vision and artificial intelligence methodologies in a new `frame' for the achievement of better results regarding efficiency, products quality and automated service. In this paper the visual detection and classification of different types of defects on solder joints in PC boards is presented by combining several image processing methods, such as smoothing, segmentation, edge detection, contour extraction and shape analysis. The results of this paper are based on simulated solder defects and a real one.

  12. Laser assisted soldering: microdroplet accumulation with a microjet device.

    Science.gov (United States)

    Chan, E K; Lu, Q; Bell, B; Motamedi, M; Frederickson, C; Brown, D T; Kovach, I S; Welch, A J

    1998-01-01

    We investigated the feasibility of a microjet to dispense protein solder for laser assisted soldering. Successive micro solder droplets were deposited on rat dermis and bovine intima specimens. Fixed laser exposure was synchronized with the jetting of each droplet. After photocoagulation, each specimen was cut into two halves at the center of solder coagulum. One half was fixed immediately, while the other half was soaked in phosphate-buffered saline for a designated hydration period before fixation (1 hour, 1, 2, and 7 days). After each hydration period, all tissue specimens were prepared for scanning electron microscopy (SEM). Stable solder coagulum was created by successive photocoagulation of microdroplets even after the soldered tissue exposed to 1 week of hydration. This preliminary study suggested that tissue soldering with successive microdroplets is feasible even with fixed laser parameters without active feedback control.

  13. Development of Pb-Free Nanocomposite Solder Alloys

    Directory of Open Access Journals (Sweden)

    Animesh K. Basak

    2018-04-01

    Full Text Available As an alternative to conventional Pb-containing solder material, Sn–Ag–Cu (SAC based alloys are at the forefront despite limitations associated with relatively poor strength and coarsening of grains/intermetallic compounds (IMCs during aging/reflow. Accordingly, this study examines the improvement of properties of SAC alloys by incorporating nanoparticles in it. Two different types of nanoparticles were added in monolithic SAC alloy: (1 Al2O3 or (2 Fe and their effect on microstructure and thermal properties were investigated. Addition of Fe nanoparticles leads to the formation of FeSn2 IMCs alongside Ag3Sn and Cu6Sn5 from monolithic SAC alloy. Addition of Al2O3 nano-particles do not contribute to phase formation, however, remains dispersed along primary β-Sn grain boundaries and act as a grain refiner. As the addition of either Fe or Al2O3 nano-particles do not make any significant effect on thermal behavior, these reinforced nanocomposites are foreseen to provide better mechanical characteristics with respect to conventional monolithic SAC solder alloys.

  14. Radiation shielding plate

    International Nuclear Information System (INIS)

    Kobayashi, Torakichi; Sugawara, Takeo.

    1983-01-01

    Purpose: To reduce the weight and stabilize the configuration of a radiation shielding plate which is used in close contact with an object to be irradiated with radiation rays. Constitution: The radiation shielding plate comprises a substrate made of lead glass and a metallic lead coating on the surface of the substrate by means of plating, vapor deposition or the like. Apertures for permeating radiation rays are formed to the radiation shielding plate. Since the shielding plate is based on a lead glass plate, a sufficient mechanical strength can be obtained with a thinner structure as compared with the conventional plate made of metallic lead. Accordingly, if the shielding plate is disposed on a soft object to be irradiated with radiation rays, the object and the plate itself less deform to obtain a radiation irradiation pattern with distinct edges. (Moriyama, K.)

  15. Microstructural and mechanical properties analysis of extruded Sn–0.7Cu solder alloy

    Directory of Open Access Journals (Sweden)

    Abdoul-Aziz Bogno

    2015-01-01

    Full Text Available The properties and performance of lead-free solder alloys such as fluidity and wettability are defined by the alloy composition and solidification microstructure. Rapid solidification of metallic alloys is known to result in refined microstructures with reduced microsegregation and improved mechanical properties of the final products as compared to normal castings. The rapidly solidified Sn-based solders by melt spinning were shown to be suitable for soldering with low temperature and short soldering duration. In the present study, rapidly solidified Sn–0.7 wt.%Cu droplets generated by impulse atomization (IA were achieved as well as directional solidification under transient conditions at lower cooling rate. This paper reports on a comparative study of the rapidly solidified and the directionally solidified samples. Different but complementary characterization techniques were used to fully analyze the solidification microstructures of the samples obtained under the two cooling regimes. These include X-ray diffractometry (XRD and scanning electron microscopy (SEM. In order to compare the tensile strength and elongation to fracture of the directionally solidified ingot and strip castings with the atomized droplet, compaction and extrusion of the latter were carried out. It was shown that more balanced and superior tensile mechanical properties are available for the hot extruded samples from compacted as-atomized Sn–0.7 wt.%Cu droplets. Further, elongation-to-fracture was 2–3× higher than that obtained for the directionally solidified samples.

  16. Processing and Characterization of NiTi Shape Memory Alloy Particle Reinforced Sn-In Solders

    National Research Council Canada - National Science Library

    Chung, Kohn C

    2006-01-01

    .... In previous work, it was proposed that reinforcement of solder by NiTi shape memory alloy particles to form smart composite solder reduces the inelastic strain of the solder and hence, may enhance...

  17. Effect of nano-scale morphology on micro-channel wall surface and electrical characterization in lead silicate glass micro-channel plate

    Science.gov (United States)

    Cai, Hua; Li, Fangjun; Xu, Yanglei; Bo, Tiezhu; Zhou, Dongzhan; Lian, Jiao; Li, Qing; Cao, Zhenbo; Xu, Tao; Wang, Caili; Liu, Hui; Li, Guoen; Jia, Jinsheng

    2017-10-01

    Micro-channel plate (MCP) is a two dimensional arrays of microscopic channel charge particle multiplier. Silicate composition and hydrogen reduction are keys to determine surface morphology of micro-channel wall in MCP. In this paper, lead silicate glass micro-channel plates in two different cesium contents (0at%, 0.5at%) and two different hydrogen reduction temperatures (400°C,450°C) were present. The nano-scale morphology, elements content and chemical states of microporous wall surface treated under different alkaline compositions and reduction conditions was investigated by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS), respectively. Meanwhile, the electrical characterizations of MCP, including the bulk resistance, electron gain and the density of dark current, were measured in a Vacuum Photoelectron Imaging Test Facility (VPIT).The results indicated that the granular phase occurred on the surface of microporous wall and diffuses in bulk glass is an aggregate of Pb atom derived from the reduction of Pb2+. In micro-channel plate, the electron gain and bulk resistance were mainly correlated to particle size and distribution, the density of dark current (DDC) went up with the increasing root-mean-square roughness (RMS) on the microporous wall surface. Adding cesiums improved the size of Pb atomic aggregation, lowered the relative concentration of [Pb] reduced from Pb2+ and decreased the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a less dark current. Increasing hydrogen reduction temperature also improved the size of Pb atomic aggregation, but enhanced the relative concentration of [Pb] and enlarged the total roughness of micro-channel wall surface, leading a higher bulk resistance, a lower electron gain and a larger dark current. The reasons for the difference of electrical characteristics were discussed.

  18. Effect of Solder Flux Residues on Corrosion of Electronics

    DEFF Research Database (Denmark)

    Hansen, Kirsten Stentoft; Jellesen, Morten Stendahl; Møller, Per

    2009-01-01

    Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA...... testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper....

  19. Mechanical properties of soldered joints of niobium base alloys

    International Nuclear Information System (INIS)

    Grishin, V.L.

    1980-01-01

    Mechanical properties of soldered joints of niobium alloys widely distributed in industry: VN3, VN4, VN5A, VN5AE, VN5AEP etc., 0.6-1.2 mm thick are investigated. It is found out that the usage of zirconium-vanadium, titanium-tantalum solders for welding niobium base alloys permits to obtain soldered joints with satisfactory mechanical properties at elevated temperatures

  20. What makes people leave their food? The interaction of personal and situational factors leading to plate leftovers in canteens.

    Science.gov (United States)

    Lorenz, Bettina Anne-Sophie; Hartmann, Monika; Langen, Nina

    2017-09-01

    In order to provide a basis for the reduction of food losses, our study analyzes individual food choice, eating and leftover behavior in a university canteen by consideration of personal, social and environmental determinants. Based on an extended literature review, a structural equation model is derived and empirically tested for a sample of 343 students. The empirical estimates support the derived model with a good overall model fit and sufficient R 2 values for dependent variables. Hence, our results provide evidence for a general significant impact of behavioral intention and related personal and social determinants as well as for the relevance of environmental/situational determinants such as portion sizes and palatability of food for plate leftovers. Moreover, we find that environmental and personal determinants are interrelated and that the impact of different determinants is relative to perceived time constraints during a visit of the university canteen. Accordingly, we conclude that simple measures to decrease avoidable food waste may take effects via complex and interrelated behavioral structures and that future research should focus on these effects to understand and change food leftover behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. PCBs with immersion tin finish - some experiences with lead-free reflow process

    Energy Technology Data Exchange (ETDEWEB)

    Bukat, K.; Koziol, G.; Sitek, J.; Borecki, J.; Hackiewicz, H. [Tele and Radio Research Inst., Warsaw (Poland); Merkle, H.; Schroeder, S. [Ormecon Chemie GmbH and Co. KG, Ammersbek (Germany); Girulska, A.; Gardela, K. [Eldos Sp. z o.o., Wroclaw (Poland)

    2004-07-01

    Substitution of lead-free solders in electronic assemblies requires changes in the conventional SnPb finishes of PCBs. The Craft project ''PRINT'' objectives respond to this challenge. Its main goal is to develop and implement the new technology of high solderability immersion tin for printed circuit boards at small and medium enterprises. The subject of the research was organic based immersion tin coating which would fulfil demands of SMT. In the paper the results of reflow soldering process on PCBs covered by Ormecon registered immersion tin finish with using lead-free solder pastes will be described. Solderability of tin coating as well as wettability of lead-free solder paste will be presented. (orig.)

  2. Interfacial microstructures and solder joint strengths of the Sn-8Zn-3Bi and Sn-9Zn-lAl Pb-free solder pastes on OSP finished printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.-T. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China); Hsi, C.-S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Wang, M.-C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: mcwang@kmu.edu.tw; Chang, T.-C.; Liang, M.-K. [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China)

    2008-07-14

    Two kinds of lead-free solders, Sn-8Zn-3Bi and Sn-9Zn-lAl, were used to mount passive components onto printed circuit boards via a re-flow soldering process. The samples were stored at 150 deg. C for 200, 400, 600, 800, and 1100 h. The microstructures of the samples after aged at 150 deg. C for various times were characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and the analyzed of solder joint shear strengths. The joint strength between Sn-8Zn-3Bi and Cu pad was about 4.0 {+-} 0.3 kg, while the strength between Sn-9Zn-lAl and Cu pad had values of 2.6 {+-} 0.1 kg. Both kinds of solder joints exhibited reduced strengths with increasing aging times. After aging at 150 deg. C for 1100 h, the joints strengths of Sn-8Zn-3Bi and Sn-9Zn-lAl were 1.8 {+-} 0.3 and 1.7 {+-} 0.3 kg, respectively. Both the Sn-8Zn-3Bi and Sn-9Zn-lAl joints showed brittle fracture behaviors. A flat layer of Cu{sub 5}Zn{sub 8} intermetallic compound (IMC) was formed between Sn-8Zn-3Bi solder and Cu pad after reflow. When the aging time was increased to 400 h, Zn-depletion and formation of Cu{sub 6}Sn{sub 5} IMC were observed in the solders due to the interaction between the tin and zinc compounds. The interaction between Sn-9Zn-lAl solder and Cu pad had similar behavior, however, Cu{sub 6}Sn{sub 5} IMC formed in Sn-9Zn-lAl solder when after aging at 150 deg. C for 600 h. As the aging time increased, both types of solders generated clear IMC spalling layers with large and continuous voids. Those voids substantially decreased the joint strength.

  3. Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

    Directory of Open Access Journals (Sweden)

    Mohd Nizam Ab. Rahman

    2014-12-01

    Full Text Available The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB. The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm, and the solder height is the table speed of the SP machine (2.5 mm/s.

  4. Recovery of Tin and Nitric Acid from Spent Solder Stripping Solutions

    International Nuclear Information System (INIS)

    Ahn, Jae-Woo; Ryu, Seong-Hyung; Kim, Tae-young

    2015-01-01

    Spent solder-stripping solutions containing tin, copper, iron, and lead in nitric acid solution, are by-products of the manufacture of printed-circuit boards. The recovery of these metals and the nitric acid, for re-use has economic and environmental benefits. In the spent solder-stripping solution, a systematic method to determine a suitable process for recovery of valuable metals and nitric acid was developed. Initially, more than 90% of the tin was successfully recovered as high-purity SnO 2 by thermal precipitation at 80 ℃ for 3 hours. About 94% of the nitric acid was regenerated effectively from the spent solutions by diffusion dialysis, after which there remained copper, iron, and lead in solution. Leakage of tin through the anion-exchange membrane was the lowest (0.026%), whereas Pb-leakage was highest (4.26%). The concentration of the regenerated nitric acid was about 5.1 N.

  5. Laser-activated protein solder for peripheral nerve repair

    Science.gov (United States)

    Trickett, Rodney I.; Lauto, Antonio; Dawes, Judith M.; Owen, Earl R.

    1995-05-01

    A 100 micrometers core optical fiber-coupled 75 mW diode laser operating at a wavelength of 800 nm has been used in conjunction with a protein solder to stripe weld severed rat tibial nerves, reducing the long operating time required for microsurgical nerve repair. Welding is produced by selective laser denaturation of the albumin based solder which contains the dye indocyanine green. Operating time for laser soldering was 10 +/- 5 min. (n equals 20) compared to 23 +/- 9 min. (n equals 10) for microsuturing. The laser solder technique resulted in patent welds with a tensile strength of 15 +/- 5 g, while microsutured nerves had a tensile strength of 40 +/- 10 g. Histopathology of the laser soldered nerves, conducted immediately after surgery, displayed solder adhesion to the outer membrane with minimal damage to the inner axons of the nerves. An in vivo study is under way comparing laser solder repaired tibial nerves to conventional microsuture repair. At the time of submission 15 laser soldered nerves and 7 sutured nerves were characterized at 3 months and showed successful regeneration with compound muscle action potentials of 27 +/- 8 mV and 29 +/- 8 mW respectively. A faster, less damaging and long lasting laser based anastomotic technique is presented.

  6. Soldering of copper-clad niobium--titanium superconductor composite

    International Nuclear Information System (INIS)

    Moorhead, A.J.; Woodhouse, J.J.; Easton, D.S.

    1977-04-01

    When superconductivity is applied to various electrical devices, the joining of the superconducting material and the performance of the joints are generally crucial to the successful operation of the system. Although many techniques are being considered for joining composite superconductors, soldering is the most common. We determined the wetting and flow behavior of various solder and flux combinations on a copper-clad Nb-Ti composite, developed equipment and techniques for soldering and inspection of lap joints, and determined the shear strength of joints at temperatures down to -269 0 C (4 0 K). We studied 15 solders and 17 commercial and experimental fluxes in the wettability and flow tests. A resistance unit was built for soldering test specimens. A series of samples soldered with 80 Pb-20 Sn, 83 Pb-15 Sn-2 Sb, 97.5 Pb-1.5 Ag-1 Sn, 80 In-15 Pb-5 Ag, or 25 In-37.5 Pb-37.5 Sn (wt percent) was inspected by three nondestructive techniques. Through-transmission ultrasound gave the best correlation with nonbond areas revealed in peel tests. Single-lap shear specimens soldered with 97.5 Pb-1.5 Ag-1 Sn had the highest strength (10.44 ksi, 72 MPa) and total elongation (0.074 in., 1.88 mm) at -269 0 C (4 0 K) of four solders tested

  7. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array

    Science.gov (United States)

    Zhou, Li

    2018-01-01

    This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method. PMID:29466310

  8. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array.

    Science.gov (United States)

    Yan, Gang; Zhou, Li

    2018-02-21

    This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method.

  9. Integration of environmentally compatible soldering technologies for waste minimization

    International Nuclear Information System (INIS)

    Hosking, F.M.

    1992-01-01

    There has been a concentrated effort throughout the international microelectronics industry to phase out chlorofluorocarbon (CFC) materials and alleviate the serious problem of ozone depletion created by the release of CFCS. The development of more environmentally compatible manufacturing technologies is the cornerstone of this effort. Alternative materials and processes for cleaning and soldering have received special attention. Electronic. soldering typically utilizes rosin-based fluxes to promote solder wettability. Flux residues must be removed from the soldered parts when high product reliability is essential. Halogenated or CFC solvents have been the principle chemicals used to clean the residues. With the accelerated push to eliminate CFCs in the US by 1995, CFC-free solvents, aqueous-based cleaning, water soluble or ''no clean'' fluxes, and fluxless soldering technologies are being developed and quickly integrated into manufacturing practice. Sandia's Center for Solder Science and Technology has been ch g a variety of fluxless and alternative soldering technologies for DOE's waste minimization program. The work has focused on controlled atmosphere, laser, and ultrasonic fluxless soldering, protective metallic and organic coatings, and fluxes which have water soluble or low solids-based chemistries. With the increasing concern that Pb will also be banned from electronic soldering, Sandia has been characterizing the wetting, aging, and mechanical properties of Pb-fire solder alloys. The progress of these integrated studies will be discussed. Their impact on environmentally compatible manufacturing will be emphasized. Since there is no universal solution to the various environmental, safety, and health issues which currently face industry, the proposed technologies offer several complementary materials and processing options from which one can choose

  10. Magnesium Diboride Current Leads

    Science.gov (United States)

    Panek, John

    2010-01-01

    A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.

  11. Intense generation of respirable metal nanoparticles from a low-power soldering unit

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, Virginia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Irusta, Silvia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Balas, Francisco [Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Instituto de Carboquímica – Consejo Superior de Investigaciones Científicas (ICB-CSIC), 50018 Zaragoza (Spain); Santamaria, Jesus, E-mail: Jesus.Santamaria@unizar.es [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain)

    2013-07-15

    Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10{sup 6} particles/cm{sup 3}) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals.

  12. Intense generation of respirable metal nanoparticles from a low-power soldering unit

    International Nuclear Information System (INIS)

    Gómez, Virginia; Irusta, Silvia; Balas, Francisco; Santamaria, Jesus

    2013-01-01

    Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10 6 particles/cm 3 ) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals

  13. Lead-Free Electronics: Impact for Space Electronics

    Science.gov (United States)

    Sampson, Michael J.

    2010-01-01

    Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

  14. Soldering formalism in noncommutative field theory: a brief note

    International Nuclear Information System (INIS)

    Ghosh, Subir

    2004-01-01

    In this Letter, I develop the soldering formalism in a new domain--the noncommutative planar field theories. The soldering mechanism fuses two distinct theories showing opposite or complimentary properties of some symmetry, taking into account the interference effects. The above mentioned symmetry is hidden in the composite (or soldered) theory. In the present work it is shown that a pair of noncommutative Maxwell-Chern-Simons theories, having opposite signs in their respective topological terms, can be consistently soldered to yield the Proca model (Maxwell theory with a mass term) with corrections that are at least quadratic in the noncommutativity parameter. We further argue that this model can be thought of as the noncommutative generalization of the Proca theory of ordinary spacetime. It is well known that abelian noncommutative gauge theory bears a close structural similarity with non-abelian gauge theory. This fact is manifested in a non-trivial way if the present Letter is compared with existing literature, where soldering of non-abelian models are discussed. Thus the present work further establishes the robustness of the soldering programme. The subtle role played by gauge invariance (or the lack of it), in the above soldering process, is revealed in an interesting way

  15. Utilization of Pb-free solders in MEMS packaging

    Science.gov (United States)

    Selvaduray, Guna S.

    2003-01-01

    Soldering of components within a package plays an important role in providing electrical interconnection, mechanical integrity and thermal dissipation. MEMS packages present challenges that are more complex than microelectronic packages because they are far more sensitive to shock and vibration and also require precision alignment. Soldering is used at two major levels within a MEMS package: at the die attach level and at the component attach level. Emerging environmental regulations worldwide, notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies, due to the inherent toxicity of Pb. This has provided the driving force for development and deployment of Pb-free solder alloys. A relatively large number of Pb-free solder alloys have been proposed by various researchers and companies. Some of these alloys have also been patented. After several years of research, the solder alloy system that has emerged is based on Sn as a major component. The electronics industry has identified different compositions for different specific uses, such as wave soldering, surface mount reflow, etc. The factors that affect choice of an appropriate Pb-free solder can be divided into two major categories, those related to manufacturing, and those related to long term reliability and performance.

  16. Fatigue and thermal fatigue of Pb-Sn solder joints

    International Nuclear Information System (INIS)

    Frear, D.; Grivas, D.; McCormack, M.; Tribula, D.; Morris, J.W. Jr.

    1987-01-01

    This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55 0 C and 125 0 C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb

  17. Sound radiated by the interaction of non-homogeneous turbulence on a transversely sheared flow with leading and trailing edges of semi-infinite flat plate

    Science.gov (United States)

    Afsar, Mohammed; Sassanis, Vasilis

    2017-11-01

    The small amplitude unsteady motion on a transversely sheared mean flow is determined by two arbitrary convected quantities with a particular choice of gauge in which the Fourier transform of the pressure is linearly-related to a scalar potential whose integral solution can be written in terms of one of these convected quantities. This formulation becomes very useful for studying Rapid-distortion theory problems involving solid surface interaction. Recent work by Goldstein et al. (JFM, 2017) has shown that the convected quantities are related to the turbulence by exact conservation laws, which allow the upstream boundary conditions for interaction of a turbulent shear flow with a solid-surface (for example) to be derived self-consistently with appropriate asymptotic separation of scales. This result requires the imposition of causality on an intermediate variable within the conservation laws that represents the local particle displacement. In this talk, we use the model derived in Goldstein et al. for trailing edge noise and compare it to leading edge noise on a semi-infinite flat plate positioned parallel to the level curves of the mean flow. Since the latter represents the leading order solution for the aerofoil interaction problem, these results are expected to be generic. M.Z.A. would also like to thank Strathclyde University for financial support from the Chancellor's Fellowship.

  18. Manipulation and soldering of carbon nanotubes using atomic force microscope

    International Nuclear Information System (INIS)

    Kashiwase, Yuta; Ikeda, Takayuki; Oya, Takahide; Ogino, Toshio

    2008-01-01

    Manipulation of carbon nanotubes (CNTs) by an atomic force microscope (AFM) and soldering of CNTs using Fe oxide nanoparticles are described. We succeeded to separate a CNT bundle into two CNTs or CNT bundles, to move the separated CNT to a desirable position, and to bind it to another bundle. For the accurate manipulation, load of the AFM cantilever and frequency of the scan were carefully selected. We soldered two CNTs using an Fe oxide nanoparticle prepared from a ferritin molecule. The adhesion forces between the soldered CNTs were examined by an AFM and it was found that the CNTs were bound, though the binding force was not strong

  19. Non-contact estimation of the bond quality in soldered thin laminate by laser generated lamb waves; Laser reiki ramuha ni yoru handazuke sekisohaku no setsugo seijo no hisesshoku hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Kasama, H.; Futatsugi, T.; Cho, H.; Takemoto, M. [Aoyama-Gakuin University, Tokyo (Japan). Faculty of Science and Engineering

    1998-03-20

    The bond quality of a solder-bonded copper laminated plate was modeled into rigid contact (rc) and slip contact (sc) to calculate the velocity dispersion of lamb waves. The velocity dispersion of laser generated lamb waves was measured, and the bond quality or the thickness of a solder layer was evaluated by non-contact. In the model whose bond surface is rc, the velocity dispersion of lamb waves can be calculated under conditions where the stress and displacement in an interface are continuous. In the model whose bond surface is sc, it can be calculated under conditions where an interface slips freely. Weak bond indicates the velocity dispersion between rc and sc. In this model, the velocity dispersion can also be calculated by a change in the thickness of a solder layer and used for quantitative evaluation of a bond interface. A three-layer solder bond manufactured for trial could be evaluated from the velocity dispersion of laser lamb waves. At the room temperature, the change in bond quality near the solder melting point of bond laminate that was judged as rc was investigated. When the solidus temperature is exceeded, the amplitude of lamb waves and the velocity dispersion changed largely. The amplitude of lamb waves increases as the liquid phase ratio increases. The bond quality near the solder melting point can be evaluated using lamb waves. 9 refs., 10 figs., 2 tabs.

  20. Crystal plasticity finite element analysis of deformation behaviour in SAC305 solder joint

    Science.gov (United States)

    Darbandi, Payam

    Due to the awareness of the potential health hazards associated with the toxicity of lead (Pb), actions have been taken to eliminate or reduce the use of Pb in consumer products. Among those, tin (Sn) solders have been used for the assembly of electronic systems. Anisotropy is of significant importance in all structural metals, but this characteristic is unusually strong in Sn, making Sn based solder joints one of the best examples of the influence of anisotropy. The effect of anisotropy arising from the crystal structure of tin and large grain microstructure on the microstructure and the evolution of constitutive responses of microscale SAC305 solder joints is investigated. Insights into the effects of key microstructural features and dominant plastic deformation mechanisms influencing the measured relative activity of slip systems in SAC305 are obtained from a combination of optical microscopy, orientation imaging microscopy (OIM), slip plane trace analysis and crystal plasticity finite element (CPFE) modeling. Package level SAC305 specimens were subjected to shear deformation in sequential steps and characterized using optical microscopy and OIM to identify the activity of slip systems. X-ray micro Laue diffraction and high energy monochromatic X-ray beam were employed to characterize the joint scale tensile samples to provide necessary information to be able to compare and validate the CPFE model. A CPFE model was developed that can account for relative ease of activating slip systems in SAC305 solder based upon the statistical estimation based on correlation between the critical resolved shear stress and the probability of activating various slip systems. The results from simulations show that the CPFE model developed using the statistical analysis of activity of slip system not only can satisfy the requirements associated with kinematic of plastic deformation in crystal coordinate systems (activity of slip systems) and global coordinate system (shape changes

  1. Effect of soldering techniques and gap distance on tensile strength of soldered Ni-Cr alloy joint.

    Science.gov (United States)

    Lee, Sang-Yeob; Lee, Jong-Hyuk

    2010-12-01

    The present study was intended to evaluate the effect of soldering techniques with infrared ray and gas torch under different gap distances (0.3 mm and 0.5 mm) on the tensile strength and surface porosity formation in Ni-Cr base metal alloy. Thirty five dumbbell shaped Ni-Cr alloy specimens were prepared and assigned to 5 groups according to the soldering method and the gap distance. For the soldering methods, gas torch (G group) and infrared ray (IR group) were compared and each group was subdivided by corresponding gap distance (0.3 mm: G3 and IR3, 0.5 mm: G5, IR5). Specimens of the experimental groups were sectioned in the middle with a diamond disk and embedded in solder blocks according to the predetermined distance. As a control group, 7 specimens were prepared without sectioning or soldering. After the soldering procedure, a tensile strength test was performed using universal testing machine at a crosshead speed 1 mm/min. The proportions of porosity on the fractured surface were calculated on the images acquired through the scanning electronic microscope. Every specimen of G3, G5, IR3 and IR5 was fractured on the solder joint area. However, there was no significant difference between the test groups (P > .05). There was a negative correlation between porosity formation and tensile strength in all the specimens in the test groups (P tensile strength of joints and porosity formations between the gas-oxygen torch soldering and infrared ray soldering technique or between the gap distance of 0.3 mm and 0.5 mm.

  2. Strength of joints brazed with two-phase solders

    International Nuclear Information System (INIS)

    Shnyakin, N.S.; Parfenova, L.V.; Ekatova, A.S.; Prilepskaya, I.V.

    1976-01-01

    Dependence of the structure and strength of soldered joints upon a gap size in case of 1Kh18N10T stainless steel soldering with a double-phase solder of Ni-Zn-Cu system is described. Butt and lap joints have been subjected to soldering with gas-flame and induction heating. The optimum conditions of the solder crystallization are determined with wedge-gap samples. The studies show that the character of distribution of a fusible β-phase in metal depends upon a gap size. With gaps up to 0.1 mm the β-phase enriched with a fusible component (zinc) runs as a continuous thin interlayer in the middle of the seam. As a result of zinc evaporation from the β-phase this interlayer becomes internally oxidized. After the sample is broken an oxidized fracture gives one the impression of a poor fusion in the middle part of the joint. The ultimate strength of butt joints is 15-20 kgf/sq.mm. A value of thermal expansion of 1Kh18N10T steel samples, 1-5 mm thick, has been experimentally determined for butt soldering. The elongation of two halves of the sample is measured by an indicator and proved to be 0.89 mm for a 50x50x2 mm sample at a soldering temperature of 1.100 deg C. The paper presents methods for the calculation of an optimal gap value for butt soldering with a local gas-flame and induction heating

  3. Tensile strength of two soldered alloys (Minalux and Verabond2

    Directory of Open Access Journals (Sweden)

    Mir Mohammad Rezaee S

    2002-07-01

    Full Text Available Recently. Minalux alloy, a base metal free from Be, has been presented on the market while no special soldering has been recommended for it. On the other hand, based on the manufacturer's claim, this alloy is similar to Verabond2. The aim of this study was to investigate the tensile strength of Minalux and Verabond2, soldered by Verasolder. Twelve standard dambble shape samples, with the length of 18 mm and the diameter of 3mm, were prepared from each alloy. Six samples of each alloy were divided into two pieces with carboradom disk. Soldering gap distance was 0.3mm, measured by a special jig and they were soldered by Verasolder alloy. Six other samples, of both Iranian and foreign unsoldered alloys were considered as control group. Then samples were examined under tensile force and their tensile strength was recorded. Two- way variance analysis showed that the tensile strength of Minalux alloy and Verabond2 were not statistically significant (Verasoler 686, Minalux 723, but after soldering, such difference became significant (Minalux 308, Verabond2 432. Verabond2 showed higher tensile strength after soldering.

  4. Features of Pd-Ni-Fe solder system for vacuum brazing of low alloy steels

    International Nuclear Information System (INIS)

    Radzievskij, V.N.; Kurochko, R.S.; Lotsmanov, S.N.; Rymar', V.I.

    1975-01-01

    The brazing solder of the Pd-Ni-Fe alloyed with copper and lithium, in order to decrease the melting point and provide for a better spreading, when soldered in vacuum ensures a uniform strength of soldered joints with the base metal of low-alloyed steels of 34KHNIM-type. The properties of low-alloyed steel joints brazed with the Pd-Ni-Fe-system solder little depend on the changes in the soldering parameters. The soldered joint keeps a homogeneous structure after all the stages of heat treatment (annealing, quenching and tempering)

  5. Characterizing the Soldering Alloy Type In–Ag–Ti and the Study of Direct Soldering of SiC Ceramics and Copper

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2018-04-01

    Full Text Available The aim of the research was to characterize the soldering alloy In–Ag–Ti type, and to study the direct soldering of SiC ceramics and copper. The In10Ag4Ti solder has a broad melting interval, which mainly depends on its silver content. The liquid point of the solder is 256.5 °C. The solder microstructure is composed of a matrix with solid solution (In, in which the phases of titanium (Ti3In4 and silver (AgIn2 are mainly segregated. The tensile strength of the solder is approximately 13 MPa. The strength of the solder increased with the addition of Ag and Ti. The solder bonds with SiC ceramics, owing to the interaction between active In metal and silicon infiltrated in the ceramics. XRD analysis has proven the interaction of titanium with ceramic material during the formation of the new minority phases of titanium silicide—SiTi and titanium carbide—C5Ti8. In and Ag also affect bond formation with the copper substrate. Two new phases were also observed in the bond interphase—(CuAg6In5 and (AgCuIn2. The average shear strength of a combined joint of SiC–Cu, fabricated with In10Ag4Ti solder, was 14.5 MPa. The In–Ag–Ti solder type studied possesses excellent solderability with several metallic and ceramic materials.

  6. Influence of Poly(ethylene glycol) Degradation on Voiding Sporadically Occurring in Solder Joints with Electroplated Cu

    Science.gov (United States)

    Wafula, F.; Yin, L.; Borgesen, P.; Andala, D.; Dimitrov, N.

    2012-07-01

    This paper presents a comprehensive study of the effect of poly(ethylene glycol) (PEG) degradation on the void formation known to take place sporadically at the interface between electroplated Cu and Pb-free solder. Thorough chemical analysis of our plating solution, carried out at different times of the deposition process by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, reveals a dramatic shift in the peaks to lower mass range with time. Scanning electron microscopy cross-sectional images of solder joints with Cu samples that have been plated at different times in the course of solution aging show a decrease in void formation. A decreasing magnitude of the deposition overpotential also seen during aging suggests that, breaking down to lower-molecular-weight fragments, PEG loses its suppression effect and likely has lower impact on the voiding propensity. This indirect correlation is confirmed further by the use of plating solutions containing PEG with preselected molecular weight. We also report on the effect of the surface area-to-solution volume ratio on PEG degradation studied by comparative experiments performed in a 50-mL bath with a rotating disc electrode and in a larger cell (Hull cell) with volume of 267 mL. The results show that, at fixed charge per unit volume, PEG degrades at a greatly accelerated rate in the Hull cell featuring higher electrode surface-to-solution volume ratio. Analysis of solder joints with accordingly grown Cu layers suggests that the voiding decreases faster with the accelerated rate of PEG degradation.

  7. Electrical characteristics for Sn-Ag-Cu solder bump with Ti/Ni/Cu under-bump metallization after temperature cycling tests

    Science.gov (United States)

    Shih, T. I.; Lin, Y. C.; Duh, J. G.; Hsu, Tom

    2006-10-01

    Lead-free solder bumps have been widely used in current flip-chip technology (FCT) due to environmental issues. Solder joints after temperature cycling tests were employed to investigate the interfacial reaction between the Ti/Ni/Cu under-bump metallization and Sn-Ag-Cu solders. The interfacial morphology and quantitative analysis of the intermetallic compounds (IMCs) were obtained by electron probe microanalysis (EPMA) and field emission electron probe microanalysis (FE-EPMA). Various types of IMCs such as (Cu1-x,Agx)6Sn5, (Cu1-y,Agy)3Sn, and (Ag1-z,Cuz)3Sn were observed. In addition to conventional I-V measurements by a special sample preparation technique, a scanning electron microscope (SEM) internal probing system was introduced to evaluate the electrical characteristics in the IMCs after various test conditions. The electrical data would be correlated to microstructural evolution due to the interfacial reaction between the solder and under-bump metallurgy (UBM). This study demonstrated the successful employment of an internal nanoprobing approach, which would help further understanding of the electrical behavior within an IMC layer in the solder/UBM assembly.

  8. Thermal decomposition of solder flux activators under simulated wave soldering conditions

    DEFF Research Database (Denmark)

    Piotrowska, Kamila; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-01-01

    /methodology/approach: Changes in the chemical structure of the activators were studied using Fourier transform infrared spectroscopy technique and were correlated to the exposure temperatures within the range of wave soldering process. The amount of residue left on the surface was estimated using standardized acid-base...... titration method as a function of temperature, time of exposure and the substrate material used. Findings: The study shows that there is a possibility of anhydride-like species formation during the thermal treatment of fluxes containing weak organic acids (WOAs) as activators (succinic and DL...

  9. Thermal Cycling Life Prediction of Sn-3.0Ag-0.5Cu Solder Joint Using Type-I Censored Data

    Directory of Open Access Journals (Sweden)

    Jinhua Mi

    2014-01-01

    Full Text Available Because solder joint interconnections are the weaknesses of microelectronic packaging, their reliability has great influence on the reliability of the entire packaging structure. Based on an accelerated life test the reliability assessment and life prediction of lead-free solder joints using Weibull distribution are investigated. The type-I interval censored lifetime data were collected from a thermal cycling test, which was implemented on microelectronic packaging with lead-free ball grid array (BGA and fine-pitch ball grid array (FBGA interconnection structures. The number of cycles to failure of lead-free solder joints is predicted by using a modified Engelmaier fatigue life model and a type-I censored data processing method. Then, the Pan model is employed to calculate the acceleration factor of this test. A comparison of life predictions between the proposed method and the ones calculated directly by Matlab and Minitab is conducted to demonstrate the practicability and effectiveness of the proposed method. At last, failure analysis and microstructure evolution of lead-free solders are carried out to provide useful guidance for the regular maintenance, replacement of substructure, and subsequent processing of electronic products.

  10. 30 CFR 77.1112 - Welding, cutting, or soldering with arc or flame; safeguards.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... WORK AREAS OF UNDERGROUND COAL MINES Fire Protection § 77.1112 Welding, cutting, or soldering with arc or flame; safeguards. (a) When welding, cutting, or soldering with arc or flame near combustible...

  11. 30 CFR 75.1106 - Welding, cutting, or soldering with arc or flame underground.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... Protection § 75.1106 Welding, cutting, or soldering with arc or flame underground. [Statutory Provisions] All welding, cutting, or soldering with arc or flame in all underground areas of a coal mine shall, whenever...

  12. 30 CFR 77.1916 - Welding, cutting, and soldering; fire protection.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, and soldering; fire... OF UNDERGROUND COAL MINES Slope and Shaft Sinking § 77.1916 Welding, cutting, and soldering; fire protection. (a) One portable fire extinguisher shall be provided where welding, cutting, or soldering with...

  13. Influence of Co and W powders on viscosity of composite solders during soldering of specially shaped diamond-abrasive tools

    Science.gov (United States)

    Sokolov, E. G.; Aref’eva, S. A.; Svistun, L. I.

    2018-03-01

    The influence of Co and W powders on the structure and the viscosity of composite solders Sn-Cu-Co-W used for the manufacture of the specially shaped diamond tools has been studied. The solders were obtained by mixing the metallic powders with an organic binder. The mixtures with and without diamonds were applied to steel rollers and shaped substrates. The sintering was carried out in a vacuum at 820 ° C with time-exposure of 40 minutes. The influence of Co and W powders on the viscosity solders was evaluated on the basis of the study of structures and according to the results of sintering specially shaped diamond tools. It was found that to provide the necessary viscosity and to obtain the uniform diamond-containing layers on the complex shaped surfaces, Sn-Cu-Co-W solder should contain 27–35 vol % of solid phase. This is achieved with a total solder content of 24–32 wt % of cobalt powder and 7 wt % of tungsten powder.

  14. Automation of experimental research of waveguide paths induction soldering

    Science.gov (United States)

    Tynchenko, V. S.; Petrenko, V. E.; Kukartsev, V. V.; Tynchenko, V. V.; Antamoshkin, O. A.

    2018-05-01

    The article presents an automated system of experimental studies of the waveguide paths induction soldering process. The system is a part of additional software for a complex of automated control of the technological process of induction soldering of thin-walled waveguide paths from aluminum alloys, expanding its capabilities. The structure of the software product, the general appearance of the controls and the potential application possibilities are presented. The utility of the developed application by approbation in a series of field experiments was considered and justified. The application of the experimental research system makes it possible to improve the process under consideration, providing the possibility of fine-tuning the control regulators, as well as keeping the statistics of the soldering process in a convenient form for analysis.

  15. Optimization of the soldering process by the DMAIC methodology

    Directory of Open Access Journals (Sweden)

    Michał Zasadzień

    2016-06-01

    Full Text Available The chapter presents the use of the DMAIC method for the analysis and improvement of the process of soldering pins in a plug connecting a bundle of wires to the board of a controller; a part of the steering system of a car. The main problem in the soldering process, that is an unsatisfactory share of bad soldered connections between the board and the plug and the instability of that number, was identified by means of a five-phase improvement process. Key points and main causes of the defect were pointed out, and process improvement measures were suggested. Due to the analysis conducted and the correct implementation of improvement measures the share of defective connections has been decreased twofold.

  16. Bottom-up nanoarchitecture of semiconductor nano-building blocks by controllable in situ SEM-FIB thermal soldering method

    KAUST Repository

    Zhang, Xuan

    2017-08-10

    Here we demonstrate that the building blocks of semiconductor WO3 nanowires can be controllably soldered together by a novel nano-soldering technique of in situ SEM-FIB thermal soldering, in which the soldering temperature can precisely remain in an optimal range to avoid a strong thermal diffusion.

  17. Bottom-up nanoarchitecture of semiconductor nano-building blocks by controllable in situ SEM-FIB thermal soldering method

    KAUST Repository

    Zhang, Xuan; Zheng, Xiujun; Zhang, Hong; Zhang, Junli; Fu, Jiecai; Zhang, Qiang; Peng, Chaoyi; Bai, Feiming; Zhang, Xixiang; Peng, Yong

    2017-01-01

    Here we demonstrate that the building blocks of semiconductor WO3 nanowires can be controllably soldered together by a novel nano-soldering technique of in situ SEM-FIB thermal soldering, in which the soldering temperature can precisely remain in an optimal range to avoid a strong thermal diffusion.

  18. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    Science.gov (United States)

    Barbagallo, C.; Malgioglio, G. L.; Petrone, G.; Cammarata, G.

    2017-05-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

  19. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    International Nuclear Information System (INIS)

    Barbagallo, C; Petrone, G; Cammarata, G; Malgioglio, G L

    2017-01-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers. (paper)

  20. Aging effects on fracture behavior of 63Sn37Pb eutectic solder during tensile tests under the SEM

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li Mingyu; Bang Hansur

    2004-01-01

    This study investigates the influence of aging treatment on fracture behavior of Sn-Pb eutectic solder alloys at different loading rate regime during tensile tests under the scanning electron microscope. In high homologous temperature, the solder exhibit the creep behavior that could be confirmed through the phenomena of grain boundary sliding (GBS) to both as-cast and aged specimens. Owing to the large grain scale after high temperature storage, boundary behavior was limited to some extent for the difficulty in grain rotation and boundary migration. Instead, drastic intragranular deformation occurred. Also, the phase coarsening weakened the combination between lead-rich phase and tin matrix. Consequently, surface fragmentation was detected for the aged specimens. Furthermore, the fracture mechanism changed from intergranular dominated to transgranular dominated with increasing loading rate to both specimens during early stage

  1. In situ investigation of SnAgCu solder alloy microstructure

    International Nuclear Information System (INIS)

    Pietrikova, Alena; Bednarcik, Jozef; Durisin, Juraj

    2011-01-01

    Research highlights: → In situ X-ray diffraction investigation enabled detailed analysis of the melting and solidification process of the SAC305 alloy. → It was found that the SAC305 solder melts at 230 deg. C. When cooling from 240 deg. C the SAC305 alloy solidifies at the temperature of 214 deg. C. During solidification β-Sn and Cu 6 Sn 5 is also formed. Formation of Ag 3 Sn occurs at 206 deg. C and the remaining amount of alloy crystallizes approximately at 160 deg. C. → Furthermore, observation of the thermal expansion behaviour of the β-Sn tetragonal unit cell revealed linear dependence of the unit cell volume on temperature. The unit cell parameters a and c also increase linearly with the temperature. Despite the fact that the c parameter is substantially smaller than parameter a, it exhibits a significantly higher linear thermal expansion coefficient. Comparison between data obtained during heating and cooling indicates that the thermal expansion coefficient is slightly greater in the case of cooling. - Abstract: In situ X-ray diffraction experiments, using synchrotron radiation, were employed to analyze microstructure evolution of the 96.5Sn3Ag0.5Cu (wt.%)-SAC305 lead-free solder alloy during heating (30-240 deg. C), isothermal dwell (240 deg. C) and cooling (240-30 deg. C). The special emphasis was placed on the study of the melting and solidification processes, explaining formation, distribution and the order of crystallization of the crystal phases (β-Sn, intermetallic compounds) in the solder alloy. Furthermore, thermal expansion behaviour of the main constituent phase β-Sn was analyzed prior to melting and after the consequent solidification.

  2. Cold plate

    Energy Technology Data Exchange (ETDEWEB)

    Marroquin, Christopher M.; O' Connell, Kevin M.; Schultz, Mark D.; Tian, Shurong

    2018-02-13

    A cold plate, an electronic assembly including a cold plate, and a method for forming a cold plate are provided. The cold plate includes an interface plate and an opposing plate that form a plenum. The cold plate includes a plurality of active areas arranged for alignment over respective heat generating portions of an electronic assembly, and non-active areas between the active areas. A cooling fluid flows through the plenum. The plenum, at the non-active areas, has a reduced width and/or reduced height relative to the plenum at the active areas. The reduced width and/or height of the plenum, and exterior dimensions of cold plate, at the non-active areas allow the non-active areas to flex to accommodate surface variations of the electronics assembly. The reduced width and/or height non-active areas can be specifically shaped to fit between physical features of the electronics assembly.

  3. Normal and abnormal growth plate

    International Nuclear Information System (INIS)

    Kumar, R.; Madewell, J.E.; Swischuk, L.E.

    1987-01-01

    Skeletal growth is a dynamic process. A knowledge of the structure and function of the normal growth plate is essential in order to understand the pathophysiology of abnormal skeletal growth in various diseases. In this well-illustrated article, the authors provide a radiographic classification of abnormal growth plates and discuss mechanisms that lead to growth plate abnormalities

  4. Creep deformation behavior in eutectic Sn-Ag solder joints using a novel mapping technique

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, J.P.; Guo, F.; McDougall, J.; Bieler, T.R.; Subramanian, K.N.; Park, J.K.

    1999-11-01

    Creep deformation behavior was measured for 60--100 {micro}m thick solder joints. The solder joints investigated consisted of: (1) non-composite solder joints made with eutectic Sn-Ag solder, and (2) composite solder joints with eutectic Sn-Ag solder containing 20 vol.%, 5 {micro}m diameter in-situ Cu{sub 6}Sn{sub 5} intermetallic reinforcements. All creep testing in this study was carried out at room temperature. Qualitative and quantitative assessment of creep deformation was characterized on the solder joints. Creep deformation was analyzed using a novel mapping technique where a geometrical-regular line pattern was etched over the entire solder joint using excimer laser ablation. During creep, the laser-ablation (LA) pattern becomes distorted due to deformation in the solder joint. By imaging the distortion of laser-ablation patterns using the SEM, actual deformation mapping for the entire solder joint is revealed. The technique involves sequential optical/digital imaging of the deformation versus time history during creep. By tracing and recording the deformation of the LA patterns on the solder over intervals of time, local creep data are obtained in many locations in the joint. This analysis enables global and localized creep shear strains and strain rate to be determined.

  5. Influence of solder joint length to the mechanical aspect during the thermal stress analysis

    Science.gov (United States)

    Tan, J. S.; Khor, C. Y.; Rahim, Wan Mohd Faizal Wan Abd; Ishak, Muhammad Ikman; Rosli, M. U.; Jamalludin, Mohd Riduan; Zakaria, M. S.; Nawi, M. A. M.; Aziz, M. S. Abdul; Ani, F. Che

    2017-09-01

    Solder joint is an important interconnector in surface mount technology (SMT) assembly process. The real time stress, strain and displacement of the solder joint is difficult to observe and assess the experiment. To tackle these problems, simulation analysis was employed to study the von Mises stress, strain and displacement in the thermal stress analysis by using Finite element based software. In this study, a model of leadless electronic package was considered. The thermal stress analysis was performed to investigate the effect of the solder length to those mechanical aspects. The simulation results revealed that solder length gives significant effect to the maximum von Mises stress to the solder joint. Besides, changes in solder length also influence the displacement of the solder joint in the thermal environment. The increment of the solder length significantly reduces the von Mises stress and strain on the solder joint. Thus, the understanding of the physical parameter for solder joint is important for engineer prior to designing the solder joint of the electronic component.

  6. Soldering and brazing safety guide: A handbook on space practice for those involved in soldering and brazing

    Science.gov (United States)

    This manual provides those involved in welding and brazing with effective safety procedures for use in performance of their jobs. Hazards exist in four types of general soldering and brazing processes: (1) cleaning; (2) application of flux; (3) application of heat and filler metal; and (4) residue cleaning. Most hazards during those operations can be avoided by using care, proper ventilation, protective clothing and equipment. Specific process hazards for various methods of brazing and soldering are treated. Methods to check ventilation are presented as well as a check of personal hygiene and good maintenance practices are stressed. Several emergency first aid treatments are described.

  7. Influence of expander components on the processes at the negative plates of lead-acid cells on high-rate partial-state-of-charge cycling. Part I: Effect of lignosulfonates and BaSO{sub 4} on the processes of charge and discharge of negative plates

    Energy Technology Data Exchange (ETDEWEB)

    Pavlov, D.; Nikolov, P.; Rogachev, T. [Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Street, bl. 10, Sofia 1113 (Bulgaria)

    2010-07-15

    This study investigates the influence of the organic expander component (Vanisperse A) and of BaSO{sub 4} on the performance of negative lead-acid battery plates on high-rate partial-state-of-charge (HRPSoC) cycling. Batteries operating in the HRPSoC mode should be classified as a separate type of lead-acid batteries. Hence, the additives to the negative plates should differ from the conventional expander composition. It has been established that lignosulfonates are adsorbed onto the lead surface and thus impede the charge processes, which results in impaired reversibility of the charge-discharge processes and hence shorter cycle life on HRPSoC operation, limited by sulfation of the negative plates. BaSO{sub 4} exerts the opposite effect: it improves the reversibility of the processes in the HRPSoC mode and hence prolongs the cycle life of the cells. The most pronounced effect of BaSO{sub 4} has been registered when it is added in concentration of 1.0 wt.% versus the leady oxide (LO) used for paste preparation. It has also been established that BaSO{sub 4} lowers the overpotential of PbSO{sub 4} nucleation. The results of the present investigation indicate that BaSO{sub 4} affects also the crystallization process of Pb during cell charging. Thus, BaSO{sub 4} eventually improves the performance characteristics of lead-acid cells on HRPSoC cycling. (author)

  8. Influence of expander components on the processes at the negative plates of lead-acid cells on high-rate partial-state-of-charge cycling. Part II. Effect of carbon additives on the processes of charge and discharge of negative plates

    Energy Technology Data Exchange (ETDEWEB)

    Pavlov, D.; Nikolov, P.; Rogachev, T. [Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Street, bl. 10, Sofia 1113 (Bulgaria)

    2010-07-15

    Lead-acid batteries operated in the high-rate partial-state-of-charge (HRPSoC) duty rapidly lose capacity on cycling, because of sulfation of the negative plates. As the battery operates from a partially discharged state, the small PbSO{sub 4} crystals dissolve and precipitate onto the bigger crystals. The latter have low solubility and hence PbSO{sub 4} accumulates progressively in the negative plates causing capacity loss. In order to suppress this process, the rate of the charge process should be increased. In a previous publication of ours we have established that reduction of Pb{sup 2+} ions to Pb may proceed on the surface of both Pb and carbon black particles. Hence, the reversibility of the charge-discharge processes improves, which leads to improved cycle life performance of the batteries in the HRPSoC mode. However, not all carbon forms accelerate the charge processes. The present paper discusses the electrochemical properties of two groups of carbon blacks: Printex and active carbons. The influence of Vaniseprse A and BaSO{sub 4} (the other two components of the expander added to the negative plates) on the reversibility of the charge-discharge processes on the negative plates is also considered. It has been established that lignosulfonates are adsorbed onto the lead surface and retard charging of the battery. BaSO{sub 4} has the opposite effect, which improves the reversibility of the processes on cycling and hence prolongs battery life in the HRPSoC duty. It has been established that the cycle life of lead-acid cells depends on the type of carbon black or active carbon added to the negative plates. When the carbon particles are of nano-sizes (<180 nm), the HRPSoC cycle life is between 10,000 and 20,000 cycles. Lignosulfonates suppress this beneficial effect of carbon black and activated carbon additives to about 10,000 cycles. Cells with active carbons have the longest cycle life when they contain also BaSO{sub 4} but no lignosulfonate. A summary of

  9. Horizon shells and BMS-like soldering transformations

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Matthias [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); O’Loughlin, Martin [University of Nova Gorica,Vipavska 13, 5000 Nova Gorica (Slovenia)

    2016-03-07

    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  10. Thermomechanical fatigue of Sn-37 wt.% Pb model solder joints

    International Nuclear Information System (INIS)

    Liu, X.W.; Plumbridge, W.J.

    2003-01-01

    The fatigue of Sn-37 wt.% Pb model solder joints has been investigated under thermomechanical and thermal cycling. Based upon an analysis of displacements during thermomechancial cycling, a model solder joint has been designed to simulate actual joints in electronic packages. The strain-stress relationship, characterised by hysteresis loops, was determined during cycling from 30 to 125 deg. C, and the stress-range monitored throughout. The number of cycles to failure, as defined by the fall in stress range, was correlated to strain range and strain energy. The strain hardening exponent, k, varied with the definition of failure and, when a stress-range drop of 50% was used, it was 0.46. Cracks were produced during pure thermal cycling without external strains applied. These arose due to the local strains caused by thermal expansion mismatches between the solder and Cu 6 Sn 5 intermetallic layer, between the phases of solder, and due to the anisotropy of the materials. The fatigue life under thermomechanical cycling was significantly inferior to that obtained in isothermal mechanical cycling. A factor contributing to this inferiority is the internal damage produced during temperature cycling

  11. The Effect of Wetting Gravity Regime on Shear Strength of SAC and Sn-Pb Solder Lap Joints

    Science.gov (United States)

    Sona, Mrunali; Prabhu, K. Narayan

    2017-09-01

    The failure of solder joints due to imposed stresses in an electronic assembly is governed by shear bond strength. In the present study, the effect of wetting gravity regime on single-lap shear strength of Sn-0.3Ag-0.7Cu and Sn-2.5Ag-0.5Cu solder alloys reflowed between bare copper substrates as well as Ni-coated Cu substrates was investigated. Samples were reflowed for 10 s, T gz (time corresponding to the end of gravity regime) and 100 s individually and tested for single-lap shear strength. The single-lap shear test was also carried out on eutectic Sn-Pb/Cu- and Sn-Pb/Ni-coated Cu specimens to compare the shear strength values obtained with those of lead-free alloys. The eutectic Sn-Pb showed significantly higher ultimate shear strength on bare Cu substrates when compared to Sn-Ag-Cu alloys. However, SAC alloys reflowed on nickel-coated copper substrate exhibited higher shear strength when compared to eutectic Sn-Pb/Ni-coated Cu specimens. All the substrate/solder/substrate lap joint specimens that were reflowed for the time corresponding to the end of gravity regime exhibited maximum ultimate shear strength.

  12. New Coating Technique of Ceramic Implants with Different Glass Solder Matrices for Improved Osseointegration-Mechanical Investigations.

    Science.gov (United States)

    Mick, Enrico; Markhoff, Jana; Mitrovic, Aurica; Jonitz, Anika; Bader, Rainer

    2013-09-11

    Ceramics are a very popular material in dental implant technology due to their tribological properties, their biocompatibility and their esthetic appearance. However, their natural surface structure lacks the ability of proper osseointegration, which constitutes a crucial process for the stability and, thus, the functionality of a bone implant. We investigated the application of a glass solder matrix in three configurations-consisting mainly of SiO₂, Al₂O₃, K₂O and Na₂O to TZP-A ceramic specimens. The corresponding adhesive strength and surface roughness of the coatings on ceramic specimens have been analyzed. Thereby, high adhesive strength (70.3 ± 7.9 MPa) was found for the three different coatings. The obtained roughness (R z ) amounted to 18.24 ± 2.48 µm in average, with significant differences between the glass solder configurations. Furthermore, one configuration was also tested after additional etching which did not lead to significant increase of surface roughness (19.37 ± 1.04 µm) or adhesive strength (57.2 ± 5.8 MPa). In conclusion, coating with glass solder matrix seems to be a promising surface modification technique that may enable direct insertion of ceramic implants in dental and orthopaedic surgery.

  13. New Coating Technique of Ceramic Implants with Different Glass Solder Matrices for Improved Osseointegration-Mechanical Investigations

    Directory of Open Access Journals (Sweden)

    Rainer Bader

    2013-09-01

    Full Text Available Ceramics are a very popular material in dental implant technology due to their tribological properties, their biocompatibility and their esthetic appearance. However, their natural surface structure lacks the ability of proper osseointegration, which constitutes a crucial process for the stability and, thus, the functionality of a bone implant. We investigated the application of a glass solder matrix in three configurations—consisting mainly of SiO2, Al2O3, K2O and Na2O to TZP-A ceramic specimens. The corresponding adhesive strength and surface roughness of the coatings on ceramic specimens have been analyzed. Thereby, high adhesive strength (70.3 ± 7.9 MPa was found for the three different coatings. The obtained roughness (Rz amounted to 18.24 ± 2.48 µm in average, with significant differences between the glass solder configurations. Furthermore, one configuration was also tested after additional etching which did not lead to significant increase of surface roughness (19.37 ± 1.04 µm or adhesive strength (57.2 ± 5.8 MPa. In conclusion, coating with glass solder matrix seems to be a promising surface modification technique that may enable direct insertion of ceramic implants in dental and orthopaedic surgery.

  14. Effects of soldering methods on tensile strength of a gold-palladium metal ceramic alloy.

    Science.gov (United States)

    Ghadhanfari, Husain A; Khajah, Hasan M; Monaco, Edward A; Kim, Hyeongil

    2014-10-01

    The tensile strength obtained by conventional postceramic application soldering and laser postceramic welding may require more energy than microwave postceramic soldering, which could provide similar tensile strength values. The purpose of the study was to compare the tensile strength obtained by microwave postceramic soldering, conventional postceramic soldering, and laser postceramic welding. A gold-palladium metal ceramic alloy and gold-based solder were used in this study. Twenty-seven wax specimens were cast in gold-palladium noble metal and divided into 4 groups: laser welding with a specific postfiller noble metal, microwave soldering with a postceramic solder, conventional soldering with the same postceramic solder used in the microwave soldering group, and a nonsectioned control group. All the specimens were heat treated to simulate a normal porcelain sintering sequence. An Instron Universal Testing Machine was used to measure the tensile strength for the 4 groups. The means were analyzed statistically with 1-way ANOVA. The surface and fracture sites of the specimens were subjectively evaluated for fracture type and porosities by using a scanning electron microscope. The mean (standard deviation) ultimate tensile strength values were as follows: nonsectioned control 818 ±30 MPa, microwave 516 ±34 MPa, conventional 454 ±37 MPa, and laser weld 191 ±39 MPa. A 1-way ANOVA showed a significant difference in ultimate tensile strength among the groups (F3,23=334.5; Ptensile strength for gold and palladium noble metals than either conventional soldering or laser welding. Conventional soldering resulted in a higher tensile strength than laser welding. Under the experimental conditions described, either microwave or conventional postceramic soldering would appear to satisfy clinical requirements related to tensile strength. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  15. Soldering-induced Cu diffusion and intermetallic compound formation between Ni/Cu under bump metallization and SnPb flip-chip solder bumps

    Science.gov (United States)

    Huang, Chien-Sheng; Jang, Guh-Yaw; Duh, Jenq-Gong

    2004-04-01

    Nickel-based under bump metallization (UBM) has been widely used as a diffusion barrier to prevent the rapid reaction between the Cu conductor and Sn-based solders. In this study, joints with and without solder after heat treatments were employed to evaluate the diffusion behavior of Cu in the 63Sn-37Pb/Ni/Cu/Ti/Si3N4/Si multilayer structure. The atomic flux of Cu diffused through Ni was evaluated from the concentration profiles of Cu in solder joints. During reflow, the atomic flux of Cu was on the order of 1015-1016 atoms/cm2s. However, in the assembly without solder, no Cu was detected on the surface of Ni even after ten cycles of reflow. The diffusion behavior of Cu during heat treatments was studied, and the soldering-process-induced Cu diffusion through Ni metallization was characterized. In addition, the effect of Cu content in the solder near the solder/intermetallic compound (IMC) interface on interfacial reactions between the solder and the Ni/Cu UBM was also discussed. It is evident that the (Cu,Ni)6Sn5 IMC might form as the concentration of Cu in the Sn-Cu-Ni alloy exceeds 0.6 wt.%.

  16. NASA-DoD Lead-Free Electronics Project

    Science.gov (United States)

    Kessel, Kurt

    2010-01-01

    This slide presentation reviews the current state of the lead-free electronics project. It characterizes the test articles, which were built with lead-free solder and lead-free component finishes. The tests performed and reported on are: thermal cycling, combine environments testing, mechanical shock testing, vibration testing and drop testing.

  17. Endurance of lead-free assembly under board level drop test and thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Xia Yanghua [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: xia_yanghua@hotmail.com; Xie Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2008-06-12

    The reliability of lead-free electronic assemblies under board level drop test and thermal cycling was investigated. TSOP (thin small outline package) devices with FeNi leads were reflow soldered on FR4 PCB (printed circuit board) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes (organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)) on the reliability performance were studied. The results show that the assemblies with ENIG finishes reveal better reliability performance than its OSP counterparts under drop test, however, the OSP samples outperform those with ENIG finishes under thermal cycling. The failure mechanism is different under these two test conditions: the solder joints fracture into the intermetallic compounds (IMCs) layer under drop test, and cracks initiate in the bulk solder under thermal cycling. The surface finishes have an effect on the failure mode. The propagation of crack in the ENIG case is along the device/solder interface, while in the case of OSP, the crack extends parallel to the solder/PCB interface.

  18. Improving the mechanical performance of Sn57.6Bi0.4Ag solder joints on Au/Ni/Cu pads during aging and electromigration through the addition of tungsten (W) nanoparticle reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi, E-mail: yili64-c@my.cityu.edu.hk [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Luo, Kaiming; Lim, Adeline B.Y.; Chen, Zhong [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Wu, Fengshun [School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan (China); Chan, Y.C. [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2016-07-04

    Sn57.6Bi0.4Ag solder has been reinforced successfully through the addition of tungsten (W) nanoparticles at a concentration of 0.5 wt%. With the addition of W nanoparticles, the solder matrix lamellar interphase spacing was reduced by 31.0%. Due to the dispersion of W nanoparticles and the consequently refined microstructure, the mechanical properties of the solder alloy were enhanced, as indicated by a 6.2% improvement in the microhardness. During the reflow of solder on Au/Ni/Cu pads, the entire Au layer dissolved into the molten solder rapidly and a large number of (Au,Ni)(Sn,Bi){sub 4} particles were formed. The fracture path of the as-reflowed joint was within the solder region, showing ductile characteristic, and the shear strength was reinforced by 8.2%, due to the enhanced mechanical properties of the solder. During the subsequent aging process, the Au migrated back towards the interface and a thick layer of interfacial (Au,Ni)(Sn,Bi){sub 4} IMC was formed, leading to the shift of the fracture path to the interfacial IMC region, the transformation to brittle fracture and the deterioration of the strength of the joint, due to Au embrittlement. By adding W nanoparticles, the migration of Au was mitigated and the thickness of the (Au,Ni)(Sn,Bi){sub 4} layer was reduced significantly, which reduced the Au embrittlement-induced deterioration of the strength of the joint. During electromigration, the segregation of the Bi-rich and Sn-rich phases and the accumulation of the (Au,Ni)(Sn,Bi){sub 4} layer at cathode interface were mitigated by the addition of W nanoparticles, which improved the electromigration resistance.

  19. Interfacial reaction of Sn-based solder joint in the package system

    Science.gov (United States)

    Gu, Huandi

    In this thesis, I report a study on the effect of the solder size on intermetallic layer formation by comparing the morphology change and growth rate of two different size solder joint aged at a same temperature for different aging time. The layer thickness and microstructure were analyzed using scanning electron microscopy (SEM). Photoshop was used to measure the thickness of intermetallic compound. Two different size of solder joints with composition of Sn-Ag-Cu (305) were used.

  20. Laser tissue welding mediated with a protein solder

    Science.gov (United States)

    Small, Ward, IV; Heredia, Nicholas J.; Celliers, Peter M.; Da Silva, Luiz B.; Eder, David C.; Glinsky, Michael E.; London, Richard A.; Maitland, Duncan J.; Matthews, Dennis L.; Soltz, Barbara A.

    1996-05-01

    A study of laser tissue welding mediated with an indocyanine green dye-enhanced protein solder was performed. Freshly obtained sections of porcine artery were used for the experiments. Sample arterial wall thickness ranged from two to three millimeters. Incisions approximately four millimeters in length were treated using an 805 nanometer continuous- wave diode laser coupled to a one millimeter diameter fiber. Controlled parameters included the power delivered by the laser, the duration of the welding process, and the concentration of dye in the solder. A two-color infrared detection system was constructed to monitor the surface temperatures achieved at the weld site. Burst pressure measurements were made to quantify the strengths of the welds immediately following completion of the welding procedure.

  1. Effect of nano Co reinforcements on the structure of the Sn-3.0Ag-0.5Cu solder in liquid and after reflow solid states

    Energy Technology Data Exchange (ETDEWEB)

    Yakymovych, Andriy, E-mail: yakymovych@univie.ac.at [Department of Inorganic Chemistry – Functional Materials, University of Vienna, Währinger Str. 42, 1090 Vienna (Austria); Department of Metal Physics, Ivan Franko National University of Lviv, Kyrylo i Mephodiy Str. 8, 79005 Lviv (Ukraine); Mudry, Stepan; Shtablavyi, Ihor [Department of Metal Physics, Ivan Franko National University of Lviv, Kyrylo i Mephodiy Str. 8, 79005 Lviv (Ukraine); Ipser, Herbert [Department of Inorganic Chemistry – Functional Materials, University of Vienna, Währinger Str. 42, 1090 Vienna (Austria)

    2016-09-15

    Sn-Ag-Cu (SAC) alloys are commonly recognized as lead-free solders employed in the electronics industry. However, some disadvantages in mechanical properties and their higher melting temperatures compared to Pb-Sn solders prompt new research relating to reinforcement of existing SAC solders. One of the ways to reinforce these solder materials is the formation of composites with nanoparticles as filler materials. Accordingly, this study presents structural features of nanocomposite (Sn-3.0Ag-0.5Cu){sub 100−x}(nanoCo){sub x} solders with up to 0.8 wt% nano Co. The effect of nano-sized Co particles was investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD) in both liquid and solid states, and scanning electron microscopy (SEM). The experimental data of DTA are compared with available literature data for bulk Sn-3.0Ag-0.5Cu alloy to check the capability of minor nano-inclusions to decrease the melting temperature of the SAC solder. The combination of structural data in liquid and solid states provides important information about the structural transformations of liquid Sn-3.0Ag-0.5Cu alloys caused by minor Co additions and the phase formation during crystallization. Furthermore, scanning electron microscopy has shown the mutual substitution of Co and Cu atoms in the Cu{sub 6}Sn{sub 5} and CoSn{sub 3} phases, respectively. - Highlights: • Differential thermal analysis of nanocomposite (Sn-3.0Ag-0.5Cu){sub 100−x}(nanoCo){sub x} alloys. • Structural transformations of liquid Sn-3.0Ag-0.5Cu solder by minor Co additions. • Structure data of the solid quaternary (Sn-3.0Ag-0.5Cu){sub 100−x}(Co){sub x} alloys. • Substitution of Co and Cu atoms in the Cu{sub 6}Sn{sub 5} and CoSn{sub 3} phases.

  2. Quality Analysis of Welded and Soldered Joints of Cu-Nb Microcomposite Wires

    Directory of Open Access Journals (Sweden)

    Nikolaj VIŠNIAKOV

    2011-03-01

    Full Text Available Quality analysis of welded and soldered joints of Cu-Nb microcomposite wires has been performed. Quality and mechanical characteristics of joints as ultimate tensile stress limit and elongation at break were measured with an universal testing machine and controlled visually using an optical microscope. Two wires joints were soldered with silver and copper solders and put into steel and copper sleeve respectively. Another two wires joints were soldered with silver solder and welded without any reinforcement. Joints soldered with the silver solder and steel sleeve have demonstrated the best mechanical characteristics: ultimate tensile stress limit of 650 MPa and elongation at break of 0.85 %. Joints soldered with the copper sleeve have no advantages comparing with the soldered butt joint. Ultimate tensile stress limit and elongation at break were in 300 MPa - 350 MPa and in 0.35 % - 0.45 % ranges respectively. Two welded joints had ultimate tensile stress limit of 470 MPa and elongation at break of 0.71 %. In all joints the microstructure of Nb filaments was destroyed and mechanical properties have been specified by mechanical strength of copper and sleeve materials only.http://dx.doi.org/10.5755/j01.ms.17.1.242

  3. Influence of Difference Solders Volume on Intermetallic Growth of Sn-4.0Ag-0.5Cu/ENEPIG

    Directory of Open Access Journals (Sweden)

    Saliza Azlina O.

    2016-01-01

    Full Text Available In recent years, portable electronic packaging products such as smart phones, tablets, notebooks and other gadgets have been developed with reduced size of component packaging, light weight, high speed and with enhanced performance. Thus, flip chip technology with smaller solder sphere sizes that would produce fine solder joint interconnections have become essential in order to fulfill these miniaturization requirements. This study investigates the interfacial reactions and intermetallics formation during reflow soldering and isothermal aging between Sn-4.0Ag-0.5Cu (SAC405 and electroless nickel/immersion palladium/immersion gold (EN(PEPIG. Solder diameters of 300 μm and 700 μm were used to compare the effect of solder volume on the solder joint microstructure. The solid state isothermal aging was performed at 125°C starting from 250 hours until 2000 hours. The results revealed that only (Cu,Ni6Sn5 IMC was found at the interface during reflow soldering while both (Cu,Ni6Sn5 and (Ni,Cu3Sn4 IMC have been observed after aging process. Smaller solder sizes produced thinner IMC than larger solder joints investigated after reflow soldering, whereas the larger solders produced thinner IMC than the smaller solders after isothermal aging. Aging duration of solder joints has been found to be increase the IMC’s thickness and changed the IMC morphologies to spherical-shaped, compacted and larger grain size.

  4. Comparative Evaluation of Marginal Accuracy of a Cast Fixed Partial Denture Compared to Soldered Fixed Partial Denture Made of Two Different Base Metal Alloys and Casting Techniques: An In vitro Study.

    Science.gov (United States)

    Jei, J Brintha; Mohan, Jayashree

    2014-03-01

    The periodontal health of abutment teeth and the durability of fixed partial denture depends on the marginal adaptation of the prosthesis. Any discrepancy in the marginal area leads to dissolution of luting agent and plaque accumulation. This study was done with the aim of evaluating the accuracy of marginal fit of four unit crown and bridge made up of Ni-Cr and Cr-Co alloys under induction and centrifugal casting. They were compared to cast fixed partial denture (FPD) and soldered FPD. For the purpose of this study a metal model was fabricated. A total of 40 samples (4-unit crown and bridge) were prepared in which 20 Cr-Co samples and 20 Ni-Cr samples were fabricated. Within these 20 samples of each group 10 samples were prepared by induction casting technique and other 10 samples with centrifugal casting technique. The cast FPD samples obtained were seated on the model and the samples were then measured with travelling microscope having precision of 0.001 cm. Sectioning of samples was done between the two pontics and measurements were made, then the soldering was made with torch soldering unit. The marginal discrepancy of soldered samples was measured and all findings were statistically analysed. The results revealed minimal marginal discrepancy with Cr-Co samples when compared to Ni-Cr samples done under induction casting technique. When compared to cast FPD samples, the soldered group showed reduced marginal discrepancy.

  5. Effect of nano Ni additions on the structure and properties of Sn-9Zn and Sn-Zn-3Bi solders in Au/Ni/Cu ball grid array packages

    Energy Technology Data Exchange (ETDEWEB)

    Gain, Asit Kumar [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chan, Y.C. [Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: eeycchan@cityu.edu.hk; Yung, Winco K.C. [Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2009-05-25

    The effect of nano Ni additions in Sn-9Zn and Sn-8Zn-3Bi solders on their interfacial microstructures and shear loads with Au/Ni/Cu pad metallization in ball grid array (BGA) applications were investigated. After the addition of nano Ni powder in Sn-based lead-free solders, there were no significant changes in the interfacial microstructure. But, in the solder region a very fine Zn-rich phase was observed. Also on the fracture surfaces a fine Zn-Ni compound was found. After the addition of nano Ni powder in Sn-based solders, the shear loads were increased due to a refinement of the microstructure and in addition, ductile fracture surfaces were clearly observed. The shear loads of the plain Sn-9Zn and Sn-8Zn-3Bi solders after one reflow cycle were about 1798 g and 2059 g, respectively. After the addition of nano Ni powder, their loads were about 2172 g and 2212 g, respectively, after one reflow cycle and their shear loads after eight reflow cycles were about 2099 g and 2081 g, respectively.

  6. Effect of nano Ni additions on the structure and properties of Sn-9Zn and Sn-Zn-3Bi solders in Au/Ni/Cu ball grid array packages

    International Nuclear Information System (INIS)

    Gain, Asit Kumar; Chan, Y.C.; Yung, Winco K.C.

    2009-01-01

    The effect of nano Ni additions in Sn-9Zn and Sn-8Zn-3Bi solders on their interfacial microstructures and shear loads with Au/Ni/Cu pad metallization in ball grid array (BGA) applications were investigated. After the addition of nano Ni powder in Sn-based lead-free solders, there were no significant changes in the interfacial microstructure. But, in the solder region a very fine Zn-rich phase was observed. Also on the fracture surfaces a fine Zn-Ni compound was found. After the addition of nano Ni powder in Sn-based solders, the shear loads were increased due to a refinement of the microstructure and in addition, ductile fracture surfaces were clearly observed. The shear loads of the plain Sn-9Zn and Sn-8Zn-3Bi solders after one reflow cycle were about 1798 g and 2059 g, respectively. After the addition of nano Ni powder, their loads were about 2172 g and 2212 g, respectively, after one reflow cycle and their shear loads after eight reflow cycles were about 2099 g and 2081 g, respectively.

  7. Laser beam soldering of micro-optical components

    Science.gov (United States)

    Eberhardt, R.

    2003-05-01

    MOTIVATION Ongoing miniaturisation and higher requirements within optical assemblies and the processing of temperature sensitive components demands for innovative selective joining techniques. So far adhesive bonding has primarily been used to assemble and adjust hybrid micro optical systems. However, the properties of the organic polymers used for the adhesives limit the application of these systems. In fields of telecommunication and lithography, an enhancement of existing joining techniques is necessary to improve properties like humidity resistance, laserstability, UV-stability, thermal cycle reliability and life time reliability. Against this background laser beam soldering of optical components is a reasonable joining technology alternative. Properties like: - time and area restricted energy input - energy input can be controlled by the process temperature - direct and indirect heating of the components is possible - no mechanical contact between joining tool and components give good conditions to meet the requirements on a joining technology for sensitive optical components. Additionally to the laser soldering head, for the assembly of optical components it is necessary to include positioning units to adjust the position of the components with high accuracy before joining. Furthermore, suitable measurement methods to characterize the soldered assemblies (for instance in terms of position tolerances) need to be developed.

  8. Scalable Manufacturing of Solderable and Stretchable Physiologic Sensing Systems.

    Science.gov (United States)

    Kim, Yun-Soung; Lu, Jesse; Shih, Benjamin; Gharibans, Armen; Zou, Zhanan; Matsuno, Kristen; Aguilera, Roman; Han, Yoonjae; Meek, Ann; Xiao, Jianliang; Tolley, Michael T; Coleman, Todd P

    2017-10-01

    Methods for microfabrication of solderable and stretchable sensing systems (S4s) and a scaled production of adhesive-integrated active S4s for health monitoring are presented. S4s' excellent solderability is achieved by the sputter-deposited nickel-vanadium and gold pad metal layers and copper interconnection. The donor substrate, which is modified with "PI islands" to become selectively adhesive for the S4s, allows the heterogeneous devices to be integrated with large-area adhesives for packaging. The feasibility for S4-based health monitoring is demonstrated by developing an S4 integrated with a strain gauge and an onboard optical indication circuit. Owing to S4s' compatibility with the standard printed circuit board assembly processes, a variety of commercially available surface mount chip components, such as the wafer level chip scale packages, chip resistors, and light-emitting diodes, can be reflow-soldered onto S4s without modifications, demonstrating the versatile and modular nature of S4s. Tegaderm-integrated S4 respiration sensors are tested for robustness for cyclic deformation, maximum stretchability, durability, and biocompatibility for multiday wear time. The results of the tests and demonstration of the respiration sensing indicate that the adhesive-integrated S4s can provide end users a way for unobtrusive health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Thermal Analysis of the Sn-Ag-Cu-In Solder Alloy

    DEFF Research Database (Denmark)

    Sopousek, J.; Palcut, Marián; Hodúlová, Erika

    2010-01-01

    The tin-based alloy Sn-1.5Ag-0.7Cu-9.5In (composition in wt.%) is a potential candidate for lead-free soldering at temperatures close to 200°C due to the significant amount of indium. Samples of Sn-1.5Ag-0.7Cu-9.5In were prepared by controlled melting of the pure elements, followed by quenching...... to room temperature. The samples were analyzed by scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDS) and electron backscatter diffraction. The solidified melt consisted of four different phases. Solidification behavior was monitored by heat-flux differential scanning calorimetry...

  10. Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, H., E-mail: xiaohui2013@yahoo.com.cn; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

    2013-11-25

    Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R{sub 0}/R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints.

  11. Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

    International Nuclear Information System (INIS)

    Xiao, H.; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

    2013-01-01

    Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R 0 /R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints

  12. Migration of Sn and Pb from Solder Ribbon onto Ag Fingers in Field-Aged Silicon Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Wonwook Oh

    2015-01-01

    Full Text Available We investigated the migration of Sn and Pb onto the Ag fingers of crystalline Si solar cells in photovoltaic modules aged in field for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells. This phenomenon is not observed in a standard acceleration test condition for PV modules. In contrast to the acceleration test conditions, field aging subjects the PV modules to solar irradiation and moisture condensation at the interface between the solar cells and the encapsulant. The solder ribbon releases Sn and Pb via repeated galvanic corrosion and the Sn and Pb precipitate on Ag fingers due to the light-induced plating under solar irradiation.

  13. 30 CFR 77.1111 - Welding, cutting, soldering; use of fire extinguisher.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, soldering; use of fire... OF UNDERGROUND COAL MINES Fire Protection § 77.1111 Welding, cutting, soldering; use of fire extinguisher. One portable fire extinguisher shall be provided at each location where welding, cutting, or...

  14. Tissue soldering with biodegradable polymer films: in-vitro investigation of hydration effects on weld strength

    Science.gov (United States)

    Sorg, Brian S.; Welch, Ashley J.

    2001-05-01

    Previous work demonstrated increased breaking strengths of tissue repaired with liquid albumin solder reinforced with a biodegradable polymer film compared to unreinforced control specimens. It was hypothesized that the breaking strength increase was due to reinforcement of the liquid solder cohesive strength. Immersion in a moist environment can decrease the adhesion of solder to tissue and negate any strength benefits gained from reinforcement. The purpose of this study was to determine if hydrated specimens repaired with reinforced solder would still be stronger than unreinforced controls. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with 806-nm diode laser light. A poly(DL-lactic- co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). The repaired tissues were immersed in phosphate buffered saline for time periods of 1 and 2 days. The breaking strengths of all of the hydrated specimens decreased compared to the acute breaking strengths. However, the reinforced specimens still had larger breaking strengths than the unreinforced controls. These results indicate that reinforcement of a liquid albumin solder may have the potential to improve the breaking strength in a clinical setting.

  15. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

  16. Failure Mechanisms of SAC/Fe-Ni Solder Joints During Thermal Cycling

    Science.gov (United States)

    Gao, Li-Yin; Liu, Zhi-Quan; Li, Cai-Fu

    2017-08-01

    Thermal cycling tests have been conducted on Sn-Ag-Cu/Fe- xNi ( x = 73 wt.% or 45 wt.%) and Sn-Ag-Cu/Cu solder joints according to the Joint Electron Device Engineering Council industrial standard to study their interfacial reliability under thermal stress. The interfacial intermetallic compounds formed for solder joints on Cu, Fe-73Ni, and Fe-45Ni were 4.5 μm, 1.7 μm, and 1.4 μm thick, respectively, after 3000 cycles, demonstrating excellent diffusion barrier effect of Fe-Ni under bump metallization (UBM). Also, two deformation modes, viz. solder extrusion and fatigue crack formation, were observed by scanning electron microscopy and three-dimensional x-ray microscopy. Solder extrusion dominated for solder joints on Cu, while fatigue cracks dominated for solder joints on Fe-45Ni and both modes were detected for those on Fe-73Ni. Solder joints on Fe-Ni presented inferior reliability during thermal cycling compared with those on Cu, with characteristic lifetime of 3441 h, 3190 h, and 1247 h for Cu, Fe-73Ni, and Fe-45Ni UBM, respectively. This degradation of the interfacial reliability for solder joints on Fe-Ni is attributed to the mismatch in coefficient of thermal expansion (CTE) at interconnection level. The CTE mismatch at microstructure level was also analyzed by electron backscatter diffraction for clearer identification of recrystallization-related deformation mechanisms.

  17. Investigation of moisture uptake into printed circuit board laminate and solder mask materials

    DEFF Research Database (Denmark)

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Borgaonkar, Shruti

    2017-01-01

    with different solder mask materials and exposed to saturated water vapour and liquid water. The solder masks are characterised for their microstructure and constituent phases using scanning electron microscopy and X-ray diffraction. The observations are correlated with themoisture absorption characteristic...

  18. Transected sciatic nerve repair by diode laser protein soldering.

    Science.gov (United States)

    Fekrazad, Reza; Mortezai, Omid; Pedram, MirSepehr; Kalhori, Katayoun Am; Joharchi, Khojasteh; Mansoori, Korosh; Ebrahimi, Roja; Mashhadiabbas, Fatemeh

    2017-08-01

    Despite advances in microsurgical techniques, repair of peripheral nerve injuries (PNI) is still a major challenge in regenerative medicine. The standard treatment for PNI includes suturing and anasthomosis of the transected nerve. The objective of this study was to compare neurorraphy (nerve repair) using standard suturingto diode laser protein soldering on the functional recovery of transected sciatic nerves. Thirty adult male Fischer-344 Wistar rats were randomly assigned to 3 groups: 1. The control group, no repair, 2. the standard of care suture group, and 3. The laser/protein solder group. For all three groups, the sciatic nerve was transected and the repair was done immediately. For the suture repair group, 10.0 prolene suture was used and for the laser/protein solder group a diode laser (500mW output power) in combination with bovine serum albumen and indocyanine green dye was used. Behavioral assessment by sciatic functional index was done on all rats biweekly. At 12weeks post-surgery, EMG recordings were done on all the rats and the rats were euthanized for histological evaluation of the sciatic nerves. The one-way ANOVA test was used for statistical analysis. The average time required to perform the surgery was significantly shorter for the laser-assisted nerve repair group compared to the suture group. The EMG evaluation revealed no difference between the two groups. Based on the sciatic function index the laser group was significantly better than the suture group after 12weeks (pneurorraphy using standard suturing methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Effects of occupational lead exposure.

    Science.gov (United States)

    Wang, Y L; Lu, P K; Chen, Z Q; Liang, Y X; Lu, Q M; Pan, Z Q; Shao, M

    1985-01-01

    Fifty-three workers in a battery factory, 52 solderers in a television factory, and 50 embroidery workers (a reference group) were studied. The average air lead levels of the three workplaces were 0.578 mg/m3, 0.002 mg/m3, and 0.001 mg/m3, respectively. Adverse effects in terms of clinical manifestations and biochemical criteria were evident among the battery factory workers. A significant dose-response relationship existed between the toxic effects and the air lead levels. The solderers showed no apparent abnormalities in comparison with the embroidery workers. The early clinical manifestations were dysfunction of the central nervous system, indigestion, arthralgia, and myalgia in the extremities. A positive association was observed between the prevalence of fatigue, mild abdominal pain, and arthralgia and the blood lead (PbB), urinary lead (PbU), and zinc protoporphyrin (ZPP) levels. The symptomatic threshold values of PbB, PbU, and ZPP were 30 micrograms/dl (1.5 mumol/l), 0.045 mg/l (0.2 mumol/l), and 40 micrograms/dl (0.7 mumol/l), respectively. The PbB, PbU, free erythrocyte protoporphyrin, and ZPP levels and the blood aminolevulinic dehydratase ratio could be used as indicators of lead exposure, although ZPP is preferred for a preventive monitoring program. The motor and sensory conduction velocities of the median nerve were slower in the exposed groups than in the reference group. No effects on behavioral function were observed among the solderers.

  20. Reliability of Wind Turbine Components-Solder Elements Fatigue Failure

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    on the temperature mean and temperature range. Constant terms and model errors are estimated. The proposed methods are useful to predict damage values for solder joint in power electrical components. Based on the proposed methods it is described how to find the damage level for a given temperature loading profile....... The proposed methods are discussed for application in reliability assessment of Wind Turbine’s electrical components considering physical, model and measurement uncertainties. For further research it is proposed to evaluate damage criteria for electrical components due to the operational temperature...

  1. Pressure brazing of ceramics to metals with copper solder

    International Nuclear Information System (INIS)

    Pavlova, M.A.; Metelkin, I.I.

    1986-01-01

    The effect on the quality of joints brazed with copper of different non metallized aluminooxide dielectrics with metals and alloys of a series of technological parameters (temperature, pressure, holding, and medium) in the course of pressure brazing is investigated. It is shown that in case of brazing with kovar and nickel the character of dependences is identical, however in all cases the joints with nickel are more durable. For the ceramics - molybdenum system characterized by weak interaction with copper solder kinetic dependences have no maximum and only under holding of more than 20 min the constant strength of 150-190 MPa is attained

  2. Processing and characterization of device solder interconnection and module attachment for power electronics modules

    Science.gov (United States)

    Haque, Shatil

    This research is focused on the processing of an innovative three-dimensional packaging architecture for power electronics building blocks with soldered device interconnections and subsequent characterization of the module's critical interfaces. A low-cost approach termed metal posts interconnected parallel plate structure (MPIPPS) was developed for packaging high-performance modules of power electronics building blocks (PEBB). The new concept implemented direct bonding of copper posts, not wire bonding of fine aluminum wires, to interconnect power devices as well as joining the different circuit planes together. We have demonstrated the feasibility of this packaging approach by constructing PEBB modules (consisting of Insulated Gate Bipolar Transistors (IGBTs), diodes, and a few gate driver elements and passive components). In the 1st phase of module fabrication with IGBTs with Si3N 4 passivation, we had successfully fabricated packaged devices and modules using the MPIPPS technique. These modules were tested electrically and thermally, and they operated at pulse-switch and high power stages up to 6kW. However, in the 2nd phase of module fabrication with polyimide passivated devices, we experienced significant yield problems due to metallization difficulties of these devices. The under-bump metallurgy scheme for the development of a solderable interface involved sputtering of Ti-Ni-Cu and Cr-Cu, and an electroless deposition of Zn-Ni-Au metallization. The metallization process produced excellent yield in the case of Si3N4 passivated devices. However, under the same metallization schemes, devices with a polyimide passivation exhibited inconsistent electrical contact resistance. We found that organic contaminants such as hydrocarbons remain in the form of thin monolayers on the surface, even in the case of as-received devices from the manufacturer. Moreover, in the case of polyimide passivated devices, plasma cleaning introduced a few carbon constituents on the

  3. Albumin solder covalently bound to a polymer membrane: New approach to improve binding strength in laser tissue soldering in-vitro.

    Science.gov (United States)

    Hiebl, B; Ascher, L; Luetzow, K; Kratz, K; Gruber, C; Mrowietz, C; Nehring, M E; Lendlein, A; Franke, R-P; Jung, F

    2018-01-01

    Laser tissue soldering (LTS) based on indocyanine green (ICG)-mediated heat-denaturation of proteins might be a promising alternative technique for micro-suturing, but up to now the problem of too weak shear strength of the solder welds in comparison to sutures is not solved. Earlier reports gave promising results showing that solder supported by carrier materials can enhance the cohesive strength of the liquid solder. In these studies, the solder was applied to the carriers by dip coating. Higher reliability of the connection between the solder and the carrier material is expected when the solder is bound covalently to the carrier material. In the present study a poly(ether imide) (PEI) membrane served as carrier material and ICG-supplemented albumin as solder substrate. The latter was covalently coupled to the carrier membrane under physiological conditions to prevent structural protein changes. As laser source a diode continuous-wave laser emitting at 808 nm with intensities between 250 mW and 1500 mW was utilized. The albumin functionalized carrier membrane was placed onto the tunica media of explanted pig thoracic aortae forming an overlapping area of approximately 0.5×0.5 cm2. All tests were performed in a dry state to prevent laser light absorption by water. Infrared spectroscopy, spectro-photometrical determination of the secondary and primary amine groups after acid orange II staining, contact angle measurements, and atomic force microscopy proved the successful functionalization of the PEI membrane with albumin. A laser power of 450 mW LTS could generate a membrane-blood vessel connection which was characterized by a shear strength of 0.08±0.002 MPa, corresponding to 15% of the tensile strength of the native blood vessel. Theoretically, an overlapping zone of 4.1 mm around the entire circumference of the blood vessel could have provided shear strength of the PEI membrane-blood vessel compound identical to the tensile strength of the native

  4. A flip chip process based on electroplated solder bumps

    Science.gov (United States)

    Salonen, J.; Salmi, J.

    1994-01-01

    Compared to wire bonding and TAB, flip chip technology using solder joints offers the highest pin count and packaging density and superior electrical performance. The chips are mounted upside down on the substrate, which can be made of silicon, ceramic, glass or - in some cases - even PCB. The extra processing steps required for chips are the deposition of a suitable thin film metal layer(s) on the standard Al pad and the formation of bumps. Also, the development of new fine line substrate technologies is required to utilize the full potential of the technology. In our bumping process, bump deposition is done by electroplating, which was chosen for its simplicity and economy. Sputter deposited molybdenum and copper are used as thin film layers between the aluminum pads and the solder bumps. A reason for this choice is that the metals can be selectively etched after bumping using the bumps as a mask, thus circumventing the need for a separate mask for etching the thin film metals. The bumps are electroplated from a binary Pb-Sn bath using a thick liquid photoresist. An extensively modified commercial flip chip bonder is used for alignment and bonding. Heat assisted tack bonding is used to attach the chips to the substrate, and final reflow joining is done without flux in a vacuum furnace.

  5. Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions

    Science.gov (United States)

    Simhon, David; Gabay, Ilan; Shpolyansky, Gregory; Vasilyev, Tamar; Nur, Israel; Meidler, Roberto; Hatoum, Ossama Abu; Katzir, Abraham; Hashmonai, Moshe; Kopelman, Doron

    2015-12-01

    Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing.

  6. Laser-tissue soldering with biodegradable polymer films in vitro: film surface morphology and hydration effects.

    Science.gov (United States)

    Sorg, B S; Welch, A J

    2001-01-01

    Previous research introduced the concept of using biodegradable polymer film reinforcement of a liquid albumin solder for improvement of the tensile strength of repaired incisions in vitro. In this study, the effect of creating small pores in the PLGA films on the weld breaking strength is studied. Additionally, the effect of hydration on the strength of the reinforced welds is investigated. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806-nm CW diode laser. A poly(DL-lactic-co-glycolic acid) (PLGA) film was used to reinforce the solder (the controls had solder but no reinforcement). Breaking strengths were measured acutely and after hydration in saline for 1 and 2 days. The data were analyzed by ANOVA (P < 0.05) and multiple comparisons of means were performed using the Newman-Keuls test. The creation of pores in the PLGA films qualitatively improved the film flexibility without having an apparent adverse effect on the breaking strength, while the actual technique of applying the film and solder had more of an effect. The acute maximum average breaking strengths of some of the film reinforced specimens (114.7 g-134.4 g) were significantly higher (P < 0.05) than the acute maximum average breaking strength of the unreinforced control specimens (68.3 g). Film reinforced specimens were shown to have a statistically significantly higher breaking strength than unreinforced controls after 1- and 2-day hydration. Reinforcement of liquid albumin solders in laser-assisted incision repair appears to have advantages over conventional methods that do not reinforce the cohesive strength of the solder in terms of acute breaking strength and after immersion in moist environments for short periods of time. Using a film with the solder applied to one surface only may be advantageous over other techniques.

  7. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Directory of Open Access Journals (Sweden)

    Xiuyun Zhou

    2015-10-01

    Full Text Available In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT. Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  8. Contamination profile on typical printed circuit board assemblies vs soldering process

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Purpose – The purpose of this paper was to analyse typical printed circuit board assemblies (PCBAs) processed by reflow, wave or selective wave soldering for typical levels of process-related residues, resulting from a specific or combination of soldering processes. Typical solder flux residue...... structure was identified by Fourier transform infrared spectroscopy, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined by measuring the leak current using a twin platinum electrode set-up. Localized extraction of residue was carried...

  9. Contamination profile of Printed Circuit Board Assemblies in relation to soldering types and conformal coating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Typical printed circuit board assemblies (PCBAs) processed by reflow, wave, or selective wave soldering were analysed for typical levels of process related residues, resulting from a specific or combination of soldering process. Typical solder flux residue distribution pattern, composition......, and concentration are profiled and reported. Presence of localized flux residues were visualized using a commercial Residue RAT gel test and chemical structure was identified by FT-IR, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined...

  10. Modeling of high temperature- and diffusion-controlled die soldering in aluminum high pressure die casting

    DEFF Research Database (Denmark)

    Domkin, Konstantin; Hattel, Jesper Henri; Thorborg, Jesper

    2009-01-01

    of the die lifetime based on a quantitative analysis of die soldering in the framework of the numerical simulations of the die-casting process. Full 3D simulations of the process, including the filling. solidification, and the die cooling, are carried out using the casting simulation software MAGMAsoft....... The resulting transient temperature fields on the die surface and in the casting are then post-processed to estimate the die soldering. The present work deals only with the metallurgical/chemical kind of soldering which occurs at high temperatures and involves formation and growth of intermetallic layers...

  11. Eddy current quality control of soldered current-carrying busbar splices of superconducting magnets

    CERN Document Server

    Kogan, L; Savary, F; Principe, R; Datskov, V; Rozenfel'd, E; Khudjakov, B

    2015-01-01

    The eddy current technique associated with a U-shaped transducer is studied for the quality control of soldered joints between superconducting busbars ('splices'). Two other quality control techniques, based on X-rays and direct measurement of the electrical resistance, are also studied for comparison. A comparative analysis of the advantages and disadvantages of these three methods in relation to the quality control of soldered superconducting busbar cables enclosed in copper shells is used for benchmarking. The results of inspections with the U-shaped eddy current transducer carried out on several sample joints presenting different types of soldering defects show the potential of this type of nondestructive (ND) quality control technique.

  12. CHALLENGES IN MAINTAINING DRINKING WATER QUALITY AT THE TAP: CONTAMINATION WITH TOXIC LEAD

    Science.gov (United States)

    Aging drinking water infrastructure in the US was given a grade of D (poor) by the American Society of Civil Engineers, and was voted as the most urgent of all societal infrastructure challenges. Legacy lead pipe, leaded solder and/or leaded brass are a particularly notorious old...

  13. Plate tectonics

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.

    's continental drift theory was later disproved, it was one of the first times that the idea of crustal movement had been introduced to the scientific community; and it has laid the groundwork for the development of modern plate tectonics. In the early... of the structure of the atom was to physical sciences and the theory of evolution was to the life sciences. Tectonics is the study of the forces within the Earth that give rise to continents, ocean basins, mountain ranges, earthquake belts and other large-scale...

  14. Create Your Plate

    Medline Plus

    Full Text Available ... Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective ... foods within each food category. Try these seven steps to get started: Using your dinner plate, put ...

  15. Lead-free piezoceramics.

    Science.gov (United States)

    Saito, Yasuyoshi; Takao, Hisaaki; Tani, Toshihiko; Nonoyama, Tatsuhiko; Takatori, Kazumasa; Homma, Takahiko; Nagaya, Toshiatsu; Nakamura, Masaya

    2004-11-04

    Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300 picocoulombs per newton (pC N(-1)), and texturing the material leads to a peak d33 of 416 pC N(-1). The textured material also exhibits temperature-independent field-induced strain characteristics.

  16. Effect of Solder-Joint Geometry on the Low-Cycle Fatigue Behavior of Sn- xAg-0.7Cu

    Science.gov (United States)

    Lee, Hwa-Teng; Huang, Kuo-Chen

    2016-12-01

    Low-cycle fatigue tests of Sn-Ag-Cu (SAC) Pb-free solder joints under fixed displacement were performed to evaluate the influence of Ag content (0-3 wt.%) and solder-joint geometry (barrel and hourglass types) on solder-joint fatigue behavior and reliability. The solder joints were composed of fine particles of Ag3Sn and Cu6Sn5, which aggregated as an eutectic constituent at grain boundaries of the primary β-Sn phase and formed a dense network structure. A decrease in the Ag content resulted in coarsening of the β-Sn and eutectic phases, which, in turn, decreased the strength of the joint and caused earlier failure. Solder joints in the hourglass form exhibited better fatigue performance with longer life than barrel-type joints. The sharp contact angle formed between the solder and the Cu substrate by the barrel-type joints concentrated stress, which compromised fatigue reliability. The addition of Ag to the solder, however, enhanced fatigue performance because of strengthening caused by Ag3Sn formation. The cracks of the barrel-type SAC solder joints originated mostly at the contact corner and propagated along the interfacial layer between the interfacial intermetallic compound (IMC) and solder matrix. Hourglass-type solder joints, however, demonstrated both crack initiation and propagation in the solder matrix (solder mode). The addition of 1.5-2.0 wt.% Ag to SAC solder appears to enhance the fatigue performance of solder joints while maintaining sufficient strength.

  17. A review on solder reflow and flux application for flip chip

    Science.gov (United States)

    Suppiah, Sarveshvaran; Ong, Nestor Rubio; Sauli, Zaliman; Sarukunaselan, Karunavani; Alcain, Jesselyn Barro; Visvanathan, Susthitha Menon; Retnasamy, Vithyacharan

    2017-09-01

    This paper encompassed of the evolution and key findings, critical technical challenges, solutions and bonding equipment of solder reflow in flip chip bonding. Upon scrutinizing researches done by others, it can be deduced that peak temperature, time above liquidus, soak temperature, soak time, cooling rate and reflow environment played a vital role in achieving the desired bonding profile. In addition, flux is also needed with the purpose of removing oxides/contaminations on bump surface as well as to promote wetting of solder balls. Electromigration and warpage are the two main challenges faced by solder reflow process which can be overcome by the advancement in under bump metallization (UBM) and substrate technology. The review is ended with a brief description of the current equipment used in solder reflow process.

  18. Laser welding of vas deferens in rodents: initial experience with fluid solders.

    Science.gov (United States)

    Trickett, R I; Wang, D; Maitz, P; Lanzetta, M; Owen, E R

    1998-01-01

    This study evaluates the use of sutureless laser welding for vasovasostomy. In 14 rodents, the left vas deferens underwent vasovasostomy using an albumin-based solder applied to the adventitia of the vas deferens. The solder contained the dye, indocyanine green, to allow selective absorption and denaturation by a fiber-coupled 800-nm diode laser. The right vas deferens served as a control, receiving conventional layered microsurgical repair. We used a removable 4/0 nylon stent and microclamps to appose the vas deferens during repair, with no need for stay sutures. The mean time to perform laser solder repair (23.5 min) and conventional repair (23.3 min) were not significantly different (P=0.91). However, examination after 8 weeks showed that granuloma formation (G) and patency (P) rates for the conventional suture technique (G, 14%; P, 93%) were significantly better than observed for the laser solder technique (G, 57%; P, 50%).

  19. Effects of rework on adhesion of Pb-In soldered gold thick films

    International Nuclear Information System (INIS)

    Gehman, R.W.; Becka, G.A.; Losure, J.A.

    1982-02-01

    The feasibility of repeatedly reworking Pb-In soldered joints on gold thick films was evaluated. Nailhead adhesion tests on soldered thick films typically resulted in failure within the bulk solder (50 In-50 Pb). Average strengths increased with each rework, and the failure mode changed. An increase in metalization lift-off occurred with successive reworks. An investigation was initiated to determine why these changes occurred. Based on this work, the thick film adhesion to the substrate appeared to be lowered by indium reduction of cadmium oxide and by formation of a weak, brittle intermetallic compound, Au 9 In 4 . It was concluded that two solder reworks could be conducted without significant amounts of metallization lift-off during nailhead testing

  20. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...... in a carbon matrix. Nanoscale soldering of multi-walled carbon nanotubes (MWNT) onto microelectrodes was achieved by deposition of a conducting gold line across a contact point between nanotube and electrode. The solderings were found to be mechanically stronger than the carbon nanotubes. We have positioned...... MWNTs to bridge the gap between two electrodes, and formed soldering bonds between the tube and each of the electrodes. All nanotube bridges showed ohmic resistances in the range 10-30 kΩ. We observed no increase in resistance after exposing the MWNT bridge to air for days....

  1. Microstructural Evolution and Mechanical Behavior of High Temperature Solders: Effects of High Temperature Aging

    Science.gov (United States)

    Hasnine, M.; Tolla, B.; Vahora, N.

    2018-04-01

    This paper explores the effects of aging on the mechanical behavior, microstructure evolution and IMC formation on different surface finishes of two high temperature solders, Sn-5 wt.% Ag and Sn-5 wt.% Sb. High temperature aging showed significant degradation of Sn-5 wt.% Ag solder hardness (34%) while aging has little effect on Sn-5 wt.% Sb solder. Sn-5 wt.% Ag experienced rapid grain growth as well as the coarsening of particles during aging. Sn-5 wt.% Sb showed a stable microstructure due to solid solution strengthening and the stable nature of SnSb precipitates. The increase of intermetallic compound (IMC) thickness during aging follows a parabolic relationship with time. Regression analysis (time exponent, n) indicated that IMC growth kinetics is controlled by a diffusion mechanism. The results have important implications in the selection of high temperature solders used in high temperature applications.

  2. The creep behavior of In-Ag eutectic solder joints

    International Nuclear Information System (INIS)

    Reynolds, H.L.; Kang, S.H.; Morris, J.W. Jr.; Univ. of California, Berkeley, CA

    1999-01-01

    The addition of 3 wt.% Ag to In results in a eutectic composition with improved mechanical properties while only slightly lowering the melting temperature. Steady-state creep properties of In-Ag eutectic solder joints have been measured using constant load tests at 0, 30, 60, and 90 C. Constitutive equations are derived to describe the creep behavior. The data are well represented by an equation of the form proposed by Dorn: a power-law equation applies to each independent creep mechanism. Two parallel mechanisms were observed for the In-Ag eutectic joints. The high-stress mechanism is a bulk mechanism with a thermal dependence dominated by the thermal dependence of creep in the In-rich matrix. The low-stress mechanism is a grain boundary mechanism. Results of this work are discussed with regard to creep behavior of typical eutectic systems

  3. Nanoconstruction by welding individual metallic nanowires together using nanoscale solder

    International Nuclear Information System (INIS)

    Peng, Y; Inkson, B J; Cullis, A G

    2010-01-01

    This work presents a new bottom-up nanowelding technique enabling building blocks to be assembled and welded together into complex 3D nanostructures using nanovolumes of metal solder. The building blocks of gold nanowires, (Co 72 Pt 28 /Pt) n multilayer nanowires, and nanosolder Sn 99 Au 1 alloy nanowires were successfully fabricated by a template technique. Individual metallic nanowires were picked up and assembled together. Conductive nanocircuits were then welded together using similar or dissimilar nanosolder material. At the weld sites, nanoscale volumes of a chosen metal are deposited using nanosolder of a sacrificial nanowire, which ensures that the nanoobjects to be bonded retain their structural integrity. The whole nanowelding process is clean, controllable and reliable, and ensures both mechanically strong and electrically conductive contacts.

  4. Soldered Contact and Current Risetime Effects on Negative Polarity Wire Array Z-pinches

    International Nuclear Information System (INIS)

    Chalenski, D. A.; Kusse, B. R.; Greenly, J. B.; Blesener, I. C.; McBride, R. D.; Hammer, D. A.; Knapp, P. F.

    2009-01-01

    The Cornell University COBRA pulser is a nominal 1 MA machine, capable of driving up to 32 wire cylindrical Z-pinch arrays. COBRA can operate with variable current risetimes ranging from 100 ns to 200 ns (short and long pulse, respectively). Wires are typically strung with a ''press'' contact to the electrode hardware, where the wire is loosely pulled against the hardware and held there to establish electrical contact. The machine is normally negative, but a bolt-on convolute can be used to modify the current path and effectively produce positive polarity operation at the load.Previous research with single wires on a 1-5 kA pulser has shown that soldering the wire, thereby improving the wire/electrode contact, and operating in positive polarity can improve the energy deposition into the wire and enhance wire core expansion. Negative polarity showed no difference. Previous experiments on the negative polarity, 20 MA, 100 ns Z accelerator have shown that improving the contact improved the x-ray yield.Cornell data were collected on 16-wire Aluminum Z-pinch arrays in negative polarity. Experiments were conducted with both short and long current pulses with soldered and no-soldered wire/electrode contacts. The initiation, ablation, implosion and stagnation phases were compared for these four conditions. Time dependent x-ray signals were measured using diodes and diamond detectors. An inductive voltage monitor was used to infer minimum current radius achieved, as defined by a uniform shell of current moving radially inward, producing a time dependent inductance. Total energy data were collected with a metal-strip bolometer. Self-emission data were collected by an XUV 4-frame camera and an optical streak camera.In negative polarity and with short pulses, soldering appeared to produce a smaller radius pinch and decrease variations in the x-ray pulse shape. The bolometer, laser backlighter, 4-frame and streak cameras showed negligible differences in the initiation ablation

  5. Investigation into mechanical properties of joints of heterogeneous materials brazed with high-temperature solders

    International Nuclear Information System (INIS)

    Lomenko, V.I.; Merkushev, V.P.; Borodina, L.M.; Sycheva, T.S.; Tokhtina, O.A.; Frolov, N.N.

    1988-01-01

    Mechanical properties of copper joints with copper, 12Kh18M10T steel and KhD50 composite obtained by vacuum brazing by copper-titanium solder as compared with properties of joints brazed by PSr 72 and PMFOTsr 6-4-0.03 solders in hydrogen are studied. Dependences of joints strength on temperature of contact - reactive vacuum brazing are obtained. Possible applications of joints of dissimilar materials in electrovacuum devices subjected to the effect of dynamic loadings are established

  6. Dye-enhanced protein solders and patches in laser-assisted tissue welding.

    Science.gov (United States)

    Small, W; Heredia, N J; Maitland, D J; Da Silva, L B; Matthews, D L

    1997-01-01

    This study examines the use of dye-enhanced protein bonding agents in 805 nm diode laser-assisted tissue welding. A comparison of an albumin liquid solder and collagen solid-matrix patches used to repair arteriotomies in an in vitro porcine model is presented. Extrinsic bonding media in the form of solders and patches have been used to enhance the practice of laser tissue welding. Preferential absorption of the laser wavelength has been achieved by the incorporation of chromophores. Both the solder and the patch included indocyanine green dye (ICG) to absorb the 805 nm continuous-wave diode laser light used to perform the welds. Solder-mediated welds were divided into two groups (high power/short exposure and low power/long exposure), and the patches were divided into three thickness groups ranging from 0.1 to 1.3 mm. The power used to activate the patches was constant, but the exposure time was increased with patch thickness. Burst pressure results indicated that solder-mediated and patched welds yielded similar average burst strengths in most cases, but the patches provided a higher success rate (i.e., more often exceeded 150 mmHg) and were more consistent (i.e., smaller standard deviation) than the solder. The strongest welds were obtained using 1.0-1.3 mm thick patches, while the high power/short exposure solder group was the weakest. Though the solder and patches yielded similar acute weld strengths, the solid-matrix patches facilitated the welding process and provided consistently strong welds. The material properties of the extrinsic agents influenced their performance.

  7. Evaluation of low-residue soldering for military and commercial applications: A report from the Low-Residue Soldering Task Force

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States); Burress, R.V. [SEHO (United States)] [and others

    1995-06-01

    The LRSTF combined the efforts of industry, military, and government to evaluate low-residue soldering processes for military and commercial applications. These processes were selected for evaluation because they provide a means for the military to support the presidential mandate while producing reliable hardware at a lower cost. This report presents the complete details and results of a testing program conducted by the LRSTF to evaluate low-residue soldering for printed wiring assemblies. A previous informal document provided details of the test plan used in this evaluation. Many of the details of that test plan are contained in this report. The test data are too massive to include in this report, however, these data are available on disk as Excel spreadsheets upon request. The main purpose of low-residue soldering is to eliminate waste streams during the manufacturing process.

  8. Scintillating plate calorimeter optical design

    International Nuclear Information System (INIS)

    McNeil, R.; Fazely, A.; Gunasingha, R.; Imlay, R.; Lim, J.

    1990-01-01

    A major technical challenge facing the builder of a general purpose detector for the SSC is to achieve an optimum design for the calorimeter. Because of its fast response and good energy resolution, scintillating plate sampling calorimeters should be considered as a possible technology option. The work of the Scintillating Plate Calorimeter Collaboration is focused on compensating plate calorimeters. Based on experimental and simulation studies, it is expected that a sampling calorimeter with alternating layers of high-Z absorber (Pb, W, DU, etc.) and plastic scintillator can be made compensating (e/h = 1.00) by suitable choice of the ratio of absorber/scintillator thickness. Two conceptual designs have been pursued by this subsystem collaboration. One is based on lead as the absorber, with read/out of the scintillator plates via wavelength shifter fibers. The other design is based on depleted uranium as the absorber with wavelength shifter (WLS) plate readout. Progress on designs for the optical readout of a compensating scintillator plate calorimeter are presented. These designs include readout of the scintillator plates via wavelength shifter plates or fiber readout. Results from radiation damage studies of the optical components are presented

  9. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    Directory of Open Access Journals (Sweden)

    Enrico Mick

    2015-07-01

    Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

  10. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints.

    Science.gov (United States)

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-12-01

    Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (ptensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint.

  11. An evaluation of the lap-shear test for Sn-rich solder/Cu couples: Experiments and simulation

    Science.gov (United States)

    Chawla, N.; Shen, Y.-L.; Deng, X.; Ege, E. S.

    2004-12-01

    The lap-shear technique is commonly used to evaluate the shear, creep, and thermal fatigue behavior of solder joints. We have conducted a parametric experimental and modeling study, on the effect of testing and geometrical parameters on solder/copper joint response in lap-shear. It was shown that the farfield applied strain is quite different from the actual solder strain (measured optically). Subtraction of the deformation of the Cu substrate provides a reasonable approximation of the solder strain in the elastic regime, but not in the plastic regime. Solder joint thickness has a profound effect on joint response. The solder response moves progressively closer to “true” shear response with increasing joint thickness. Numerical modeling using finite-element analyses were performed to rationalize the experimental findings. The same lap-shear configuration was used in the simulation. The input response for solder was based on the experimental tensile test result on bulk specimens. The calculated shear response, using both the commonly adopted far-field measure and the actual shear strain in solder, was found to be consistent with the trends observed in the lap-shear experiments. The geometric features were further explored to provide physical insight into the problem. Deformation of the substrate was found to greatly influence the shear behavior of the solder.

  12. Setup Time Reduction On Solder Paste Printing Machine – A Case Study

    Directory of Open Access Journals (Sweden)

    Rajesh Dhake

    2013-06-01

    Full Text Available Lean manufacturing envisages the reduction of the seven deadly wastes referred to as MUDA. Setup time forms a major component of the equipment downtime. It leads to lower machine utilization and restricts the output and product variety. This necessitates the requirement for quick setups. Single Minute Exchange of Die philosophy (a lean manufacturing tool here after referred as “SMED” is one of the important tool which aims at quick setups driving smaller lot sizes, lower production costs, improve productivity in terms of increased output, increased utilization of machine and labor hours, make additional capacity available (often at bottleneck resources, reduce scrap and rework, and increase flexibility[3]. This paper focuses on the application of Single Minute Exchange of Die[1] and Quick Changeover Philosophy[2] for reducing setup time on Solder Past Printing Machine (bottleneck machine in a electronic speedo-cluster manufacturing company. The four step SMED philosophy was adopted to effect reduction in setup time. The initial step was gathering information about the present setup times and its proportion to the total productive time. A detailed video based time study of setup activities was done to classify them into external and internal setup activities in terms of their need (i.e. preparation, replacement or adjustment, time taken and the way these could be reduced, simplified or eliminated. The improvements effected were of three categories viz., mechanical, procedural and organizational. The paper concludes by comparing the present and proposed (implemented methods of setup procedures.

  13. Leaching Studies for Copper and Solder Alloy Recovery from Shredded Particles of Waste Printed Circuit Boards

    Science.gov (United States)

    Kavousi, Maryam; Sattari, Anahita; Alamdari, Eskandar Keshavarz; Fatmehsari, Davoud Haghshenas

    2018-06-01

    Printed circuit boards (PCBs) comprise various metals such as Cu, Sn, and Pb, as well as platinum group metals. The recovery of metals from PCBs is important not only due to the waste treatment but also for recycling of valuable metals. In the present work, the leaching process of Cu, Sn, and Pb from PCBs was studied using fluoroboric acid and hydrogen peroxide as the leaching agent and oxidant, respectively. Pertinent factors including concentration of acid, temperature, liquid-solid ratio, and concentration of oxidizing agent were evaluated. The results showed 99 pct of copper and 90 pct solder alloy were dissolved at a temperature of 298 K (25 °C) for 180 minutes using 0.6 M HBF4 for the particle size range of 0.15 to 0.4 mm. Moreover, solid/liquid ratio had insignificant effect on the recovery of metals. Kinetics analysis revealed that the chemical control regime governs the process with activation energy 41.25 and 38.9 kJ/mol for copper and lead leaching reactions, respectively.

  14. Leaching Studies for Copper and Solder Alloy Recovery from Shredded Particles of Waste Printed Circuit Boards

    Science.gov (United States)

    Kavousi, Maryam; Sattari, Anahita; Alamdari, Eskandar Keshavarz; Fatmehsari, Davoud Haghshenas

    2018-03-01

    Printed circuit boards (PCBs) comprise various metals such as Cu, Sn, and Pb, as well as platinum group metals. The recovery of metals from PCBs is important not only due to the waste treatment but also for recycling of valuable metals. In the present work, the leaching process of Cu, Sn, and Pb from PCBs was studied using fluoroboric acid and hydrogen peroxide as the leaching agent and oxidant, respectively. Pertinent factors including concentration of acid, temperature, liquid-solid ratio, and concentration of oxidizing agent were evaluated. The results showed 99 pct of copper and 90 pct solder alloy were dissolved at a temperature of 298 K (25 °C) for 180 minutes using 0.6 M HBF4 for the particle size range of 0.15 to 0.4 mm. Moreover, solid/liquid ratio had insignificant effect on the recovery of metals. Kinetics analysis revealed that the chemical control regime governs the process with activation energy 41.25 and 38.9 kJ/mol for copper and lead leaching reactions, respectively.

  15. How Many Peripheral Solder Joints in a Surface Mounted Design Experience Inelastic Strains?

    Science.gov (United States)

    Suhir, E.; Yi, S.; Ghaffarian, R.

    2017-03-01

    It has been established that it is the peripheral solder joints that are the most vulnerable in the ball-grid-array (BGA) and column-grid-array (CGA) designs and most often fail. As far as the long-term reliability of a soldered microelectronics assembly as a whole is concerned, it makes a difference, if just one or more peripheral joints experience inelastic strains. It is clear that the low cycle fatigue lifetime of the solder system is inversely proportional to the number of joints that simultaneously experience inelastic strains. A simple and physically meaningful analytical expression (formula) is obtained for the prediction, at the design stage, of the number of such joints, if any, for the given effective thermal expansion (contraction) mismatch of the package and PCB; materials and geometrical characteristics of the package/PCB assembly; package size; and, of course, the level of the yield stress in the solder material. The suggested formula can be used to determine if the inelastic strains in the solder material could be avoided by the proper selection of the above characteristics and, if not, how many peripheral joints are expected to simultaneously experience inelastic strains. The general concept is illustrated by a numerical example carried out for a typical BGA package. The suggested analytical model (formula) is applicable to any soldered microelectronics assembly. The roles of other important factors, such as, e.g., solder material anisotropy, grain size, and their random orientation within a joint, are viewed in this analysis as less important factors than the level of the interfacial stress. The roles of these factors will be accounted for in future work and considered, in addition to the location of the joint, in a more complicated, more sophisticated, and more comprehensive reliability/fatigue model.

  16. Effect of gap distance on tensile strength of preceramic base metal solder joints.

    Science.gov (United States)

    Fattahi, Farnaz; Motamedi, Milad

    2011-01-01

    In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

  17. The critical oxide thickness for Pb-free reflow soldering on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chung, C. Key [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Assembly Test Global Materials, Intel Microelectronics Asia Ltd, B1, No. 205, Tun-Hwa North Road, 10595 Taipei, Taiwan (China); Chen, Y.J.; Li, C.C. [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Kao, C.R., E-mail: crkao@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China)

    2012-06-01

    Oxidation is an undesirable effect of reflow soldering. Non-wetting occurs when the oxide layer grows above the critical thickness. Characterizing the critical oxide thickness for soldering is challenging due to oxide's nano-scale thickness and irregular topographic surface. In this paper, the critical copper oxide thickness was characterized by Time-of-Flight Secondary Ion Mass Spectrometry, Scanning Electron Microscopy, Energy-Dispersive X-ray spectroscopy, and Transmission Electron Microscopy. Copper substrates were coated with an Organic-Solderable-Preservative (OSP) layer and baked at 150 Degree-Sign C and 85% Relative Humidity for different amounts of time. The onset of the non-wetting phenomenon occurred when the oxide thickness reached 18 {+-} 5 nm. As the oxide grew beyond this critical thickness, the percentage of non-wetting solder joint increased exponentially. The growth of the oxide thickness followed a parabolic rate law. The rate constant of oxidation was 0.6 Multiplication-Sign 10{sup -15} cm{sup 2} min{sup -1}. Oxidation resulted from interdiffusion of copper and oxygen atoms through the OSP and oxide layers. The oxidation mechanism will be presented and discussed. - Highlights: Black-Right-Pointing-Pointer Critical oxide thickness for Pb free solder on Cu substrate is 18 {+-} 5 nm. Black-Right-Pointing-Pointer Above the critical oxide, non-wet solder joint increases exponentially. Black-Right-Pointing-Pointer A maximum 13-nm oxide thickness is suggested for good solder joint. Black-Right-Pointing-Pointer Initial growth of oxide thickness is logarithmic and then parabolic after 12 nm. Black-Right-Pointing-Pointer Thick oxide (360-560 nm) is formed as pores shorten the oxidation path.

  18. Al and Si Alloying Effect on Solder Joint Reliability in Sn-0.5Cu for Automotive Electronics

    Science.gov (United States)

    Hong, Won Sik; Oh, Chulmin; Kim, Mi-Song; Lee, Young Woo; Kim, Hui Joong; Hong, Sung Jae; Moon, Jeong Tak

    2016-12-01

    To suppress the bonding strength degradation of solder joints in automotive electronics, we proposed a mid-temperature quaternary Pb-free Sn-0.5Cu solder alloy with minor Pd, Al, Si and Ge alloying elements. We manufactured powders and solder pastes of Sn-0.5Cu-(0.01,0.03)Al-0.005Si-(0.006-0.007)Ge alloys ( T m = 230°C), and vehicle electronic control units used for a flame-retardant-4 printed circuit board with an organic solderability preservative finish were assembled by a reflow soldering process. To investigate the degradation properties of solder joints used in engine compartments, thermal cycling tests were conducted from -40°C to 125°C (10 min dwell) for 1500 cycles. We also measured the shear strength of the solder joints in various components and observed the microstructural evolution of the solder joints. Based on these results, intermetallic compound (IMC) growth at the solder joints was suppressed by minor Pd, Al and Si additions to the Sn-0.5Cu alloy. After 1500 thermal cycles, IMC layers thicknesses for 100 parts per million (ppm) and 300 ppm Al alloy additions were 6.7 μm and 10 μm, compared to the as-reflowed bonding thicknesses of 6 μm and 7 μm, respectively. Furthermore, shear strength degradation rates for 100 ppm and 300 ppm Al(Si) alloy additions were at least 19.5%-26.2%. The cause of the improvement in thermal cycling reliability was analyzed using the (Al,Cu)-Sn, Si-Sn and Al-Sn phases dispersed around the Cu6Sn5 intermetallic at the solder matrix and bonding interfaces. From these results, we propose the possibility of a mid-temperature Sn-0.5Cu(Pd)-Al(Si)-Ge Pb-free solder for automotive engine compartment electronics.

  19. Indonesian Landforms and Plate Tectonics

    Directory of Open Access Journals (Sweden)

    Herman Th. Verstappen

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v5i3.103The horizontal configuration and vertical dimension of the landforms occurring in the tectonically unstable parts of Indonesia were resulted in the first place from plate tectonics. Most of them date from the Quaternary and endogenous forces are ongoing. Three major plates – the northward moving Indo-Australian Plate, the south-eastward moving SE-Asian Plate and the westward moving Pacific Plate - meet at a plate triple-junction situated in the south of New Guinea’s Bird’s Head. The narrow North-Moluccan plate is interposed between the Asia and Pacific. It tapers out northward in the Philippine Mobile Belt and is gradually disappearing. The greatest relief amplitudes occur near the plate boundaries: deep ocean trenches are associated with subduction zones and mountain ranges with collision belts. The landforms of the more stable areas of the plates date back to a more remote past and, where emerged, have a more subdued relief that is in the first place related to the resistance of the rocks to humid tropical weathering Rising mountain ranges and emerging island arcs are subjected to rapid humid-tropical river erosions and mass movements. The erosion products accumulate in adjacent sedimentary basins where their increasing weight causes subsidence by gravity and isostatic compensations. Living and raised coral reefs, volcanoes, and fault scarps are important geomorphic indicators of active plate tectonics. Compartmental faults may strongly affect island arcs stretching perpendicular to the plate movement. This is the case on Java. Transcurrent faults and related pull-apart basins are a leading factor where plates meet at an angle, such as on Sumatra. The most complicated situation exists near the triple-junction and in the Moluccas. Modern research methods, such as GPS measurements of plate movements and absolute dating of volcanic outbursts and raised coral reefs are important tools. The mega-landforms resulting

  20. Thermodynamic properties of the liquid Bi-Cu-Sn lead-free solder alloys

    Directory of Open Access Journals (Sweden)

    Kopyto M.

    2009-01-01

    Full Text Available The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Bi-Cu-Sn alloys using solid electrolyte galvanic cells as shown below: Kanthal+Re, Bi-Cu-Sn, SnO2 | Yttria Stabilized Zirconia | air, Pt, Po2=0.2:1 atm Measurements were carried out for three cross-sections with constant Bi/Cu ratio equal to: 1/3, 1 and 3 and for various tin content varying every 10%, resulting in a total of 26 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.

  1. Thermal analysis of selected tin-based lead-free solder alloys

    DEFF Research Database (Denmark)

    Palcut, Marián; Sopoušek, J.; Trnková, L.

    2009-01-01

    ) and thermodynamic calculations using the CALPHAD approach. The amount of the alloying elements in the materials was chosen to be close to the respective eutectic composition and the nominal compositions were the following: Sn-3.7Ag-0.7Cu, Sn-1.0Ag-0.5Cu-1Bi (in wt.%). Thermal effects during melting and solidifying...... were experimentally studied by the DSC technique. The microstructure of the samples was determined by the light microscopy and the composition of solidified phases was obtained by the energy-dispersive X-ray spectroscopy, respectively. The solidification behaviour under equilibrium conditions...

  2. The refining of secondary lead for use in advanced lead-acid batteries

    International Nuclear Information System (INIS)

    Ellis, Timothy W.; Mirza, Abbas H.

    2010-01-01

    Secondary lead, i.e. material produced by the recycling of lead-acid batteries has become the primary source of lead in much of the world. This has been important to the secondary lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses. Presently, battery manufacturing accounts for greater than 80% of lead consumption while recycled lead accounts for approximately the same market share of lead supply. These two facts strongly demonstrate the battery manufacturing and recycled lead are intimately coupled in everyday life. In this paper we will explore how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industries requirements. Particular focus will be on addressing the results presented by Prengaman on the effects of contaminant or tramp elements on gassing in lead-acid batteries. (author)

  3. Chemical wiring and soldering toward all-molecule electronic circuitry.

    Science.gov (United States)

    Okawa, Yuji; Mandal, Swapan K; Hu, Chunping; Tateyama, Yoshitaka; Goedecker, Stefan; Tsukamoto, Shigeru; Hasegawa, Tsuyoshi; Gimzewski, James K; Aono, Masakazu

    2011-06-01

    Key to single-molecule electronics is connecting functional molecules to each other using conductive nanowires. This involves two issues: how to create conductive nanowires at designated positions, and how to ensure chemical bonding between the nanowires and functional molecules. Here, we present a novel method that solves both issues. Relevant functional molecules are placed on a self-assembled monolayer of diacetylene compound. A probe tip of a scanning tunneling microscope is then positioned on the molecular row of the diacetylene compound to which the functional molecule is adsorbed, and a conductive polydiacetylene nanowire is fabricated by initiating chain polymerization by stimulation with the tip. Since the front edge of chain polymerization necessarily has a reactive chemical species, the created polymer nanowire forms chemical bonding with an encountered molecular element. We name this spontaneous reaction "chemical soldering". First-principles theoretical calculations are used to investigate the structures and electronic properties of the connection. We demonstrate that two conductive polymer nanowires are connected to a single phthalocyanine molecule. A resonant tunneling diode formed by this method is discussed. © 2011 American Chemical Society

  4. Electromigration-induced back stress in critical solder length for three-dimensional integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y. T.; Hsu, H. H.; Wu, Albert T., E-mail: atwu@ncu.edu.tw [Department of Chemical and Materials Engineering, National Central University, Jhongli City 320, Taiwan (China)

    2014-01-21

    Because of the miniaturization of electronic devices, the reliability of electromigration has become a major concern when shrinking the solder dimensions in flip-chip joints. Fast reaction between solders and electrodes causes intermetallic compounds (IMCs) to form, which grow rapidly and occupy entire joints when solder volumes decrease. In this study, U-grooves were fabricated on Si chips as test vehicles. An electrode-solder-electrode sandwich structure was fabricated by using lithography and electroplating. Gaps exhibiting well-defined dimensions were filled with Sn3.5Ag solders. The gaps between the copper electrodes in the test sample were limited to less than 15 μm to simulate microbumps. The samples were stressed at various current densities at 100 °C, 125 °C, and 150 °C. The morphological changes of the IMCs were observed, and the dimensions of the IMCs were measured to determine the kinetic growth of IMCs. Therefore, this study focused on the influence of back stress caused by microstructural evolution in microbumps.

  5. Effect of Preconditioning and Soldering on Failures of Chip Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander A.

    2014-01-01

    Soldering of molded case tantalum capacitors can result in damage to Ta205 dielectric and first turn-on failures due to thermo-mechanical stresses caused by CTE mismatch between materials used in the capacitors. It is also known that presence of moisture might cause damage to plastic cases due to the pop-corning effect. However, there are only scarce literature data on the effect of moisture content on the probability of post-soldering electrical failures. In this work, that is based on a case history, different groups of similar types of CWR tantalum capacitors from two lots were prepared for soldering by bake, moisture saturation, and longterm storage at room conditions. Results of the testing showed that both factors: initial quality of the lot, and preconditioning affect the probability of failures. Baking before soldering was shown to be effective to prevent failures even in lots susceptible to pop-corning damage. Mechanism of failures is discussed and recommendations for pre-soldering bake are suggested based on analysis of moisture characteristics of materials used in the capacitors' design.

  6. In vitro conjunctival incision repair by temperature-controlled laser soldering.

    Science.gov (United States)

    Norman, Galia; Rabi, Yaron; Assia, Ehud; Katzir, Abraham

    2009-01-01

    The common method of closing conjunctival incisions is by suturing, which is associated with several disadvantages. It requires skill to apply and does not always provide a watertight closure, which is required in some operations (e.g., glaucoma filtration). The purpose of the present study was to evaluate laser soldering as an alternative method for closing conjunctival incisions. Conjunctival incisions of 20 ex vivo porcine eyes were laser soldered using a temperature-controlled fiberoptic laser system and an albumin mixed with indocyanine green as a solder. The control group consisted of five repaired incisions by a 10-0 nylon running suture. The leak pressure of the repaired incisions was measured. The mean leak pressure in the laser-soldered group was 132 mm Hg compared to 4 mm Hg in the sutured group. There was no statistically significant difference in both the incision's length and distance from the limbus between the groups, before and after the procedure, indicating that there was no severe thermal damage. These preliminary results clearly demonstrate that laser soldering may be a useful method for achieving an immediate watertight conjunctival wound closure. This procedure is faster and easier to apply than suturing.

  7. Effect of temperature and flux concentration on soldering of base metal.

    Science.gov (United States)

    Lee, S Y; Lin, C T; Wang, M H; Tseng, H; Huang, H M; Dong, D R; Pan, L C; Shih, Y H

    2000-12-01

    The present study used the acoustic emission (AE) technique to evaluate interactions among soldering temperature, flux treatment, and the resultant ultimate tensile strength (UTS). Scanning electron microscopy (SEM) was used to examine fracture surfaces of the solder joints. Specimens were cast from removable partial denture alloy and then placed in a jig with a gap distance of 1.0 mm. A high-frequency soldering machine with an optical pyrometer was used for soldering at 1150 degrees C and 1200 degrees C, respectively. The flux concentrations were 67% and 75%. The soldered specimens were subjected to tensile test at a crosshead speed of 0.05 mm/min. During testing, acoustic emissions in the frequency range of 100--1200 kHz were collected, filtered, recorded, and processed by a sensing device. The results were analysed by ANOVA and Tukey LSD test. UTS at different temperatures showed no significant difference according to either mechanical or acoustic results. But in the 1200 degrees C group, the UTSs and AE counts showed significant differences (Pacoustic signals within the elastic deformation zone, while the 67% flux subgroup produced similar signals within the plastic deformation zone, either beyond the 0.2% yield point or before fracture.

  8. Nano-soldering of magnetically aligned three-dimensional nanowire networks

    International Nuclear Information System (INIS)

    Gao Fan; Gu Zhiyong

    2010-01-01

    It is extremely challenging to fabricate 3D integrated nanostructures and hybrid nanoelectronic devices. In this paper, we report a simple and efficient method to simultaneously assemble and solder nanowires into ordered 3D and electrically conductive nanowire networks. Nano-solders such as tin were fabricated onto both ends of multi-segmented nanowires by a template-assisted electrodeposition method. These nanowires were then self-assembled and soldered into large-scale 3D network structures by magnetic field assisted assembly in a liquid medium with a high boiling point. The formation of junctions/interconnects between the nanowires and the scale of the assembly were dependent on the solder reflow temperature and the strength of the magnetic field. The size of the assembled nanowire networks ranged from tens of microns to millimeters. The electrical characteristics of the 3D nanowire networks were measured by regular current-voltage (I-V) measurements using a probe station with micropositioners. Nano-solders, when combined with assembling techniques, can be used to efficiently connect and join nanowires with low contact resistance, which are very well suited for sensor integration as well as nanoelectronic device fabrication.

  9. AC losses for the various voltage-leads in a semi-triple layer BSCCO conductor

    International Nuclear Information System (INIS)

    Li, Z.; Ryu, K.; Hwang, S.D.; Cha, G.; Song, H.J.

    2011-01-01

    Two voltage-leads (inner-lead, outer-lead) were soldered to the wires in each layer. Voltage-lead (total-lead) was soldered to the inner layer and arranged on the surface of the outer layer. The loss from the total-lead significantly differs from the sum of the wire losses. In order to investigate the AC loss of the multilayer conductor in a high temperature superconductor cable, a voltage-lead was generally attached to the outermost layer of the conductor. But the conductor's AC loss has not been completely cleared due to the various contact positions and arrangements of the voltage-lead. In this paper, we prepared a semi-triple layer conductor consisting of an inner layer and an outer layer with double layer structure. To measure the AC loss of the conductor, two voltage-leads (inner-lead, outer-lead) were soldered to the wires in each layer and arranged along their surfaces, as well as another voltage-lead (total-lead) was soldered to the inner layer and arranged on the surface of the outer layer. The results show that the AC losses for each layer measured from the inner-lead and the outer-lead, respectively, are identical to the sum of the wire losses. The AC losses in the semi-triple layer conductor measured from the total-lead and the outer-lead are identical for the uniform layer current density, and similar to the sum of the wire losses in both layers. However, the losses measured for the non-uniform layer current density from three voltage-leads are unequal to each other, and the loss from the total-lead significantly differs from the sum of the wire losses.

  10. Reliability of Pb free solder alloys. Physical and mechanical properties; Pb free handa no shinraisei. Butsuri kikaiteki shinraisei

    Energy Technology Data Exchange (ETDEWEB)

    Sanji, M; Yoshino, M; Ishikawa, J; Takenaka, O [Denso Corp., Aichi (Japan)

    1997-10-01

    Properties of 19 different Pb free solders have been evaluated in comparison with Sn-37Pb eutectic solder. Pb free solders without Bi were on the same level as Sn-37Pb in tensile strength and elongation, and those with Bi had higher strength and lower elongation than Sn-37Pb. As the Bi content increased, strength was higher, and elongation was lower. In torsion fatigue tests, fatigue life of Pb free solders without Bi was longer than Sn-37Pb. The relationships of Coffin-Manson rule and Basquin rule with fatigue life was applicable to Pb free solder. Fatigue life of those is inferred from their tensile strength. 7 refs., 13 figs., 1 tab.

  11. In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction

    International Nuclear Information System (INIS)

    Chen, Kai; Tamura, Nobumichi; Tu, King-Ning

    2008-01-01

    The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines

  12. In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kai; Tamura, Nobumichi; Tu, King-Ning

    2008-10-31

    The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines.

  13. Design of Experiments to Determine Causes of Flex Cable Solder Wicking, Discoloration and Hole Location Defects

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Larry

    2009-04-22

    Design of Experiments (DoE) were developed and performed in an effort to discover and resolve the causes of three different manufacturing issues; large panel voids after Hot Air Solder Leveling (HASL), cable hole locations out of tolerance after lamination and delamination/solder wicking around flat flex cable circuit lands after HASL. Results from a first DoE indicated large panel voids could be eliminated by removing the pre-HASL cleaning. It also revealed eliminating the pre-HASL bake would not be detrimental when using a hard press pad lamination stackup. A second DoE indicated a reduction in hard press pad stackup lamination pressure reduced panel stretch in the y axis approximately 70%. A third DoE illustrated increasing the pre-HASL bake temperature could reduce delamination/solder wicking when using a soft press pad lamination stackup.

  14. Dissolution ad uptake of cadmium from dental gold solder alloy implants

    International Nuclear Information System (INIS)

    Bergman, B.; Bergman, M.; Soeremark, R.

    1977-01-01

    Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium ( 115 Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3 d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of 115 Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver. (author)

  15. SINGLE IMAGE CAMERA CALIBRATION IN CLOSE RANGE PHOTOGRAMMETRY FOR SOLDER JOINT ANALYSIS

    Directory of Open Access Journals (Sweden)

    D. Heinemann

    2016-06-01

    Full Text Available Printed Circuit Boards (PCB play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. Photogrammetry is an image based method for three dimensional reconstruction from two dimensional image data of an object. A precise camera calibration is indispensable for an accurate reconstruction. In our certain application it is not possible to use calibration methods with two dimensional calibration targets. Therefore a special calibration target was developed and manufactured, which allows for single image camera calibration.

  16. Comparison of implant-abutment interface misfits after casting and soldering procedures.

    Science.gov (United States)

    Neves, Flávio Domingues das; Elias, Gisele Araújo; da Silva-Neto, João Paulo; de Medeiros Dantas, Lucas Costa; da Mota, Adérito Soares; Neto, Alfredo Júlio Fernandes

    2014-04-01

    The aim of this study was to compare vertical and horizontal adjustments of castable abutments after conducting casting and soldering procedures. Twelve external hexagonal implants (3.75 × 10 mm) and their UCLA abutments were divided according their manufacturer and abutment type: PUN (plastic UCLA, Neodent), PUC (plastic UCLA, Conexão), PU3i (plastic UCLA, Biomet 3i), and PUTN (plastic UCLA with Tilite milled base, Neodent). Three infrastructures of a fixed partial implant-supported bridge with 3 elements were produced for each group. The measurements of vertical (VM) and horizontal (HM) misfits were obtained via scanning electron microscopy after completion of casting and soldering. The corresponding values were determined to be biomechanically acceptable to the system, and the results were rated as a percentage. Statistical analysis establishes differences between groups by chi-square after procedures, and McNeman's test was applied to analyze the influence of soldering over casting (α ≤ .05). For the values of VM and HM, respectively, when the casting process was complete, it was observed that 83.25% and 100% (PUTN), 33.3% and 27.75% (PUN), 33.3% and 88.8% (PUC), 33.3% and 94.35% (PU3i) represented acceptable values. After completing the requisite soldering, acceptable values were 50% and 94.35% (PUTN), 16.6% and 77.7% (PUN), 38.55% and 77.7% (PUC), and 27.75% and 94.35% (PU3i). Within the limitations of this study, it can be concluded that the premachined abutments presented more acceptable VM values. The HM values were within acceptable limits before and after the soldering procedure for most groups. Further, the soldering procedure resulted in an increase of VM in all groups.

  17. In-vitro Investigations of Skin Closure using Diode Laser and Protein Solder Containing Gold Nanoshells

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Nourbakhsh

    2010-12-01

    Full Text Available Introduction: Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nanoshells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nanoshells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after placing 50 μl of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns, and scan velocity (Vs were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nanoshell concentrations. In addition, at constant laser irradiance (I, the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to st = 1610 g/cm2 at I ~ 60 Wcm-2, T ~ 65ºC, Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nanoshells can be used as an indocyanine green dye (ICG alterative for laser tissue soldering.  Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

  18. Plating on some difficult-to-plate metals and alloys

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.

    1980-02-01

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests

  19. Physics of Failure as a Basis for Solder Elements Reliability Assessment in Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    description of the reliability. A physics of failure approach is applied. A SnAg solder component used in power electronics is used as an example. Crack propagation in the SnAg solder is modeled and a model to assess the accumulated plastic strain is proposed based on a physics of failure approach. Based...... on the proposed model it is described how to find the accumulated linear damage and reliability levels for a given temperature loading profile. Using structural reliability methods the reliability levels of the electrical components are assessed by introducing scale factors for stresses....

  20. Aging treatment characteristics of solder bump joint for high reliability optical module

    International Nuclear Information System (INIS)

    Kim, Kyung-Seob; Yu, Chung-Hee; Yang, Jun-Mo

    2004-01-01

    The joint strength and fracture surfaces of Sn-37 mass% Pb and Au stud bumps for photo diode packages after isothermal aging testing were studied experimentally. Al/Au stud bumps and Cu/Sn-37 mass% Pb solders were adopted, and aged for up to 900 h to analyze the effect of intermetallic compound (IMC). The joint strength decreased with aging time. The diffraction patterns of Cu 6 Sn 5 , scallop-shaped IMCs, and planar-shaped Cu 3 Sn were characterized using transmission electron microscopy (TEM). The formation of Kirkendall voids and the growth of IMCs at the solder were found to be a possible mechanism for joint strength reduction

  1. Microstructure and Tensile Properties of Sn-1Ag-0.5Cu Solder Alloy Bearing Al for Electronics Applications

    Science.gov (United States)

    Shnawah, Dhafer Abdul-Ameer; Said, Suhana Binti Mohd; Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum; Hoe, Teh Guan; Che, Fa Xing; Abood, Adnan Naama

    2012-08-01

    This work investigates the effects of 0.1 wt.% and 0.5 wt.% Al additions on bulk alloy microstructure and tensile properties as well as on the thermal behavior of Sn-1Ag-0.5Cu (SAC105) lead-free solder alloy. The addition of 0.1 wt.% Al reduces the amount of Ag3Sn intermetallic compound (IMC) particles and leads to the formation of larger ternary Sn-Ag-Al IMC particles. However, the addition of 0.5 wt.% Al suppresses the formation of Ag3Sn IMC particles and leads to a large amount of fine Al-Ag IMC particles. Moreover, both 0.1 wt.% and 0.5 wt.% Al additions suppress the formation of Cu6Sn5 IMC particles and lead to the formation of larger Al-Cu IMC particles. The 0.1 wt.% Al-added solder shows a microstructure with coarse β-Sn dendrites. However, the addition of 0.5 wt.% Al has a great effect on suppressing the undercooling and refinement of the β-Sn dendrites. In addition to coarse β-Sn dendrites, the formation of large Sn-Ag-Al and Al-Cu IMC particles significantly reduces the elastic modulus and yield strength for the SAC105 alloy containing 0.1 wt.% Al. On the other hand, the fine β-Sn dendrite and the second-phase dispersion strengthening mechanism through the formation of fine Al-Ag IMC particles significantly increases the elastic modulus and yield strength of the SAC105 alloy containing 0.5 wt.% Al. Moreover, both 0.1 wt.% and 0.5 wt.% Al additions worsen the elongation. However, the reduction in elongation is much stronger, and brittle fracture occurs instead of ductile fracture, with 0.5 wt.% Al addition. The two additions of Al increase both solidus and liquidus temperatures. With 0.5 wt.% Al addition the pasty range is significantly reduced and the differential scanning calorimetry (DSC) endotherm curve gradually shifts from a dual to a single endothermic peak.

  2. Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

    2009-05-27

    The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

  3. Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

    Science.gov (United States)

    Hammad, A. E.; El-Taher, A. M.

    2014-11-01

    The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.

  4. Incorporation of Interfacial Intermetallic Morphology in Fracture Mechanism Map for Sn-Ag-Cu Solder Joints

    Science.gov (United States)

    Huang, Z.; Kumar, P.; Dutta, I.; Sidhu, R.; Renavikar, M.; Mahajan, R.

    2014-01-01

    A fracture mechanism map (FMM) is a powerful tool which correlates the fracture behavior of a material to its microstructural characteristics in an explicit and convenient way. In the FMM for solder joints, an effective thickness of the interfacial intermetallic compound (IMC) layer ( t eff) and the solder yield strength ( σ ys,eff) are used as abscissa and ordinate axes, respectively, as these two predominantly affect the fracture behavior of solder joints. Earlier, a definition of t eff, based on the uniform thickness of IMC ( t u) and the average height of the IMC scallops ( t s), was proposed and shown to aptly explain the fracture behavior of solder joints on Cu. This paper presents a more general definition of t eff that is more widely applicable to a range of metallizations, including Cu and electroless nickel immersion gold (ENIG). Using this new definition of t eff, mode I FMM for SAC387/Cu joints has been updated and its validity was confirmed. A preliminary FMM for SAC387/Cu joints with ENIG metallization is also presented.

  5. Circuit reliability boosted by soldering pins of disconnect plugs to sockets

    Science.gov (United States)

    Pierce, W. B.

    1964-01-01

    Where disconnect pins must be used for wiring and testing a circuit, improved system reliability is obtained by making a permanent joint between pins and sockets of the disconnect plug. After the circuit has been tested, contact points may be fused through soldering, brazing, or welding.

  6. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  7. Fatigue damage modeling in solder interconnects using a cohesive zone approach

    NARCIS (Netherlands)

    Abdul-Baqi, A.J.J.; Schreurs, P.J.G.; Geers, M.G.D.

    2005-01-01

    The objective of this work is to model the fatigue damage process in a solder bump subjected to cyclic loading conditions. Fatigue damage is simulated using the cohesive zone methodology. Damage is assumed to occur at interfaces modeled through cohesive zones in the material, while the bulk material

  8. Design and Experiment of a Solder Paste Jetting System Driven by a Piezoelectric Stack

    Directory of Open Access Journals (Sweden)

    Shoudong Gu

    2016-06-01

    Full Text Available To compensate for the insufficiency and instability of solder paste dispensing and printing that are used in the SMT (Surface Mount Technology production process, a noncontact solder paste jetting system driven by a piezoelectric stack based on the principle of the nozzle-needle-system is introduced in this paper, in which a miniscule gap exists between the nozzle and needle during the jetting process. Here, the critical jet ejection velocity is discussed through theoretical analysis. The relations between ejection velocity and needle structure, needle velocity, and nozzle diameter were obtained by FLUENT software. Then, the prototype of the solder paste jetting system was fabricated, and the performance was verified by experiments. The effects of the gap between nozzle and needle, the driving voltage, and the nozzle diameter on the jetting performance and droplet diameter were obtained. Solder paste droplets 0.85 mm in diameter were produced when the gap between the nozzle and needle was adjusted to 10 μm, the driving voltage to 80 V, the nozzle diameter to 0.1 mm, and the variation of the droplet diameter was within ±3%.

  9. Characterizing performances of solder paste printing process at flexible manufacturing lines

    International Nuclear Information System (INIS)

    Siew, Jit Ping; Low, Heng Chin; Teoh, Ping Chow

    2015-01-01

    Solder paste printing (SPP) has been a challenge on printed circuit board (PCB) manufacturing, evident by the proliferation of solder paste inspection equipment, or substituted by rigorous non-value added activity of manual inspections. The objective of this study is to characterize the SPP performance of various products manufactured in flexible production lines with different equipment configurations, and determine areas for process improvement. The study began by collecting information on SPP performance relative to component placement (CP) process, and to the proportion of mixed products. Using a clustering algorithm to group similar elements together, SPP performance across all product-production line pairs are statistically modeled to discover the trend and the influential factors. The main findings are: (a) Ratio of overall dpku for CP and SPP processes are 2:1; (b) logistic regression models of SPP performance indicated that only effects of product-production line and solder paste printer configuration are significant; (c) PCB circuitry design with BGA components and single solder paste printer line configurations generated the highest monthly defects, with the highest variation in the latter

  10. Characterizing performances of solder paste printing process at flexible manufacturing lines

    Energy Technology Data Exchange (ETDEWEB)

    Siew, Jit Ping; Low, Heng Chin [University of Science Malaysia, 11800 Minden, Penang (Malaysia); Teoh, Ping Chow [Wawasan Open University, 54 Jalan Sultan Ahmad Shah, 10050 Penang (Malaysia)

    2015-02-03

    Solder paste printing (SPP) has been a challenge on printed circuit board (PCB) manufacturing, evident by the proliferation of solder paste inspection equipment, or substituted by rigorous non-value added activity of manual inspections. The objective of this study is to characterize the SPP performance of various products manufactured in flexible production lines with different equipment configurations, and determine areas for process improvement. The study began by collecting information on SPP performance relative to component placement (CP) process, and to the proportion of mixed products. Using a clustering algorithm to group similar elements together, SPP performance across all product-production line pairs are statistically modeled to discover the trend and the influential factors. The main findings are: (a) Ratio of overall dpku for CP and SPP processes are 2:1; (b) logistic regression models of SPP performance indicated that only effects of product-production line and solder paste printer configuration are significant; (c) PCB circuitry design with BGA components and single solder paste printer line configurations generated the highest monthly defects, with the highest variation in the latter.

  11. Hypospadias repair using laser tissue soldering (LTS): preliminary results of a prospective randomized study

    Science.gov (United States)

    Kirsch, Andrew J.; Cooper, Christopher S.; Canning, Douglas A.; Snyder, Howard M., III; Zderic, Stephen A.

    1998-07-01

    Purpose: The purpose of this study was to evaluate laser tissue soldering using an 808 nm diode laser and wavelength- matched human albumin solder for urethral surgery in children. Methods: Currently, 30 boys, ages 3 months to 8 years were randomized to standard suturing (n equals 22) or 'sutureless' laser hypospadias repair (n equals 18). Laser soldering was performed with a human albumin solder doped with indocyanine green dye (2.5 mg/ml) using a laser power output of 0.5 W, pulse duration of 0.5 sec, and interval of 0.1 sec. Power density was approximately 16 W/cm2. In the laser group, sutures were used for tissue alignment only. At the time of surgery, neourethral and penile lengths, operative time for urethral repair, and number of sutures/throws were measured. Postoperatively, patients were examined for complications of wound healing, stricture, or fistula formation. Results: Mean age, severity of urethral defect, type of repair, and neourethra length were equivalent between the two groups. Operative time was significantly faster for laser soldering in both simple (1.6 plus or minus 0.21 min, p less than 0.001) and complex (5.4 plus or minus 0.28 min, p less than 0.0001) hypospadias repairs compared to controls (10.6 plus or minus 1.4 min and 27.8 plus or minus 2.9 min, respectively). The mean number of sutures used in the laser group for simple and complex repairs (3.3 plus or minus 0.3 and 8.1 plus or minus 0.64, respectively) were significantly (p less than 0.0001) less than for controls (8.2 plus or minus 0.84 and 20 plus or minus 2.3, respectively). Followup was between 3 months and 14 months. The overall complication rate in the laser group (11%) was lower than the controls (23%). However, statistical significance (p less than 0.05) was achieved only for the subgroup of patients undergoing simple repairs (LTS, 100% success versus suturing, 69% success). Conclusions: These preliminary results indicate that laser tissue soldering for hypospadias repair

  12. A Module Experimental Process System Development Unit (MEPSDU). [flat plate solar arrays

    Science.gov (United States)

    1981-01-01

    The development of a cost effective process sequence that has the potential for the production of flat plate photovoltaic modules which meet the price goal in 1986 of 70 cents or less per Watt peak is described. The major accomplishments include (1) an improved AR coating technique; (2) the use of sand blast back clean-up to reduce clean up costs and to allow much of the Al paste to serve as a back conductor; and (3) the development of wave soldering for use with solar cells. Cells were processed to evaluate different process steps, a cell and minimodule test plan was prepared and data were collected for preliminary Samics cost analysis.

  13. Decomposition of no-clean solder flux systems and their effects on the corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Verdingovas, Vadimas; Jellesen, Morten Stendahl

    2016-01-01

    No-clean flux systems are used today for the soldering of electronic printed circuit board assemblies assuming that all the aggressive substances of the flux will vanish during the soldering process i.e. evaporate, decompose or being enclosed safely in the residues. However this is not true in most...... that the fluxes do not decompose fully within the temperature regime of the soldering process, leaving behind significant level of weak organic acid residues. The residue depending on the type and amount can be can be very aggressive towards the corrosion on the printed circuit board assemblies. The glutaric acid...

  14. Laser solder welding of articular cartilage: tensile strength and chondrocyte viability.

    Science.gov (United States)

    Züger, B J; Ott, B; Mainil-Varlet, P; Schaffner, T; Clémence, J F; Weber, H P; Frenz, M

    2001-01-01

    The surgical treatment of full-thickness cartilage defects in the knee joint remains a therapeutic challenge. Recently, new techniques for articular cartilage transplantation, such as mosaicplasty, have become available for cartilage repair. The long-term success of these techniques, however, depends not only on the chondrocyte viability but also on a lateral integration of the implant. The goal of this study was to evaluate the feasibility of cartilage welding by using albumin solder that was dye-enhanced to allow coagulation with 808-nm laser diode irradiation. Conventional histology of light microscopy was compared with a viability staining to precisely determine the extent of thermal damage after laser welding. Indocyanine green (ICG) enhanced albumin solder (25% albumin, 0.5% HA, 0.1% ICG) was used for articular cartilage welding. For coagulation, the solder was irradiated through the cartilage implant by 808-nm laser light and the tensile strength of the weld was measured. Viability staining revealed a thermal damage of typically 500 m in depth at an irradiance of approximately 10 W/cm(2) for 8 seconds, whereas conventional histologies showed only half of the extent found by the viability test. Heat-bath investigations revealed a threshold temperature of minimum 54 degrees C for thermal damage of chondrocytes. Efficient cartilage bonding was obtained by using bovine albumin solder as adhesive. Maximum tensile strength of more than 10 N/cm(2) was achieved. Viability tests revealed that the thermal damage is much greater (up to twice) than expected after light microscopic characterization. This study shows the feasibility to strongly laser weld cartilage on cartilage by use of a dye-enhanced albumin solder. Possibilities to reduce the range of damage are suggested. Copyright 2001 Wiley-Liss, Inc.

  15. Thermal Fatigue Evaluation of Pb-Free Solder Joints: Results, Lessons Learned, and Future Trends

    Science.gov (United States)

    Coyle, Richard J.; Sweatman, Keith; Arfaei, Babak

    2015-09-01

    Thermal fatigue is a major source of failure of solder joints in surface mount electronic components and it is critically important in high reliability applications such as telecommunication, military, and aeronautics. The electronic packaging industry has seen an increase in the number of Pb-free solder alloy choices beyond the common near-eutectic Sn-Ag-Cu alloys first established as replacements for eutectic SnPb. This paper discusses the results from Pb-free solder joint reliability programs sponsored by two industry consortia. The characteristic life in accelerated thermal cycling is reported for 12 different Pb-free solder alloys and a SnPb control in 9 different accelerated thermal cycling test profiles in terms of the effects of component type, accelerated thermal cycling profile and dwell time. Microstructural analysis on assembled and failed samples was performed to investigate the effect of initial microstructure and its evolution during accelerated thermal cycling test. A significant finding from the study is that the beneficial effect of Ag on accelerated thermal cycling reliability (measured by characteristic lifetime) diminishes as the severity of the accelerated thermal cycling, defined by greater ΔT, higher peak temperature, and longer dwell time increases. The results also indicate that all the Pb-free solders are more reliable in accelerated thermal cycling than the SnPb alloy they have replaced. Suggestions are made for future work, particularly with respect to the continued evolution of alloy development for emerging application requirements and the value of using advanced analytical methods to provide a better understanding of the effect of microstructure and its evolution on accelerated thermal cycling performance.

  16. Create Your Plate

    Medline Plus

    Full Text Available ... foods you want, but changes the portion sizes so you are getting larger portions of non-starchy ... plate. Then on one side, cut it again so you will have three sections on your plate. ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... of the differences in types of vegetables. When creating your plate at home, remember that half of ... effective for both managing diabetes and losing weight. Creating your plate lets you still choose the foods ...

  18. Create Your Plate

    Medline Plus

    Full Text Available ... Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get Started Safely Get And ... Plate Create Your Plate is a simple and effective way to manage your blood glucose levels and ...

  19. Create Your Plate

    Medline Plus

    Full Text Available ... Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with ... Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy ...

  20. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  1. Quantifying the dependence of Ni(P) thickness in ultrathin-ENEPIG metallization on the growth of Cu–Sn intermetallic compounds in soldering reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-Ying; Duh, Jenq-Gong, E-mail: jgd@mx.nthu.edu.tw

    2014-11-14

    A new multilayer metallization, ENEPIG (Electroless Ni(P)/Electroless Pd/Immersion Au) with ultrathin Ni(P) deposit (ultrathin-ENEPIG), was designed to be used in high frequency electronic packaging in this study because of its ultra-low electrical impedance. Sequential interfacial microstructures of commercial Sn–3.0Ag–0.5Cu solders reflowed on ultarthin-ENEPIG with Ni(P) deposit thickness ranged from 4.79 μm to 0.05 μm were first investigated. Accelerated thermal aging test was then conducted to evaluate the long-term thermal stabilization of solder joints. The results showed that P-rich intermetallic compound (IMC) layer formed when the Ni(P) thickness was greater than a critical vale (about 0.18 μm). Besides, it is interesting to mention that the growth of (Cu,Ni){sub 6}Sn{sub 5} and (Cu,Ni){sub 3}Sn IMCs was suppressed with the formation of P-rich layer, i.e., Ni{sub 3}P and Ni{sub 2}Sn{sub 1+x}P{sub 1−x} phase, even though the electroless-plated Ni(P) layer was exhausted at initial stage of reflow process. The atomic Cu flux in solder joints without P-rich layer was calculated to be several times larger than that with P-rich layer formation after calculation, which implies that the P-rich layer and ultrathin Ni(P) deposit in ENEPIG served as diffusion barrier against rapid Cu diffusion. - Highlights: • Microstructures in ultrathin-ENEPIG with various Ni(P) thickness are investigated. • P-rich IMC layer formed when the Ni(P) thickness is greater than 0.18 μm. • Secondary (Cu,Ni){sub 6}Sn{sub 5} formed when the Ni(P) thickness is between 0.18 and 0.31 μm. • Cu diffusion flux without P-rich layer is larger than those with P-rich layer. • P-rich layer in ultrathin-ENEPIG exhibits good diffusion barrier characteristic.

  2. Aerodynamic sound from a sawtooth plate with different thickness ...

    African Journals Online (AJOL)

    Acoustic performance of an airfoil can be improved with the serrated leading or trailing edge. A sawtooth plate is one of the serration shapes. In this study, the effect of sawtooth plate thickness on the aerodynamically generated noise in wake-sawtooth plate interaction at a Reynolds number of 150 is numerically investigated ...

  3. Subgrain Rotation Behavior in Sn3.0Ag0.5Cu-Sn37Pb Solder Joints During Thermal Shock

    Science.gov (United States)

    Han, Jing; Tan, Shihai; Guo, Fu

    2018-01-01

    Ball grid array (BGA) samples were soldered on a printed circuit board with Sn37Pb solder paste to investigate the recrystallization induced by subgrain rotation during thermal shock. The composition of the solder balls was Sn3.0Ag0.5Cu-Sn37Pb, which comprised mixed solder joints. The BGA component was cross-sectioned before thermal shock. The microstructure and grain orientations were obtained by a scanning electron microscope equipped with an electron back-scattered diffraction system. Two mixed solder joints at corners of the BGA component were selected as the subjects. The results showed that recrystallization occurred at the corner of the solder joints after 200 thermal shock cycles. The recrystallized subgrains had various new grain orientations. The newly generated grain orientations were closely related to the initial grain orientations, which indicated that different subgrain rotation behaviors could occur in one mixed solder joint with the same initial grain orientation. When the misorientation angles were very small, the rotation axes were about Sn [100], [010] and [001], as shown by analyzing the misorientation angles and subgrain rotation axes, while the subgrain rotation behavior with large misorientation angles in the solder joints was much more complicated. As Pb was contained in the solder joints and the stress was concentrated on the corner of the mixed solder joints, concaves and cracks were formed. When the adjacent recrystallized subgrains were separated, and the process of the continuous recrystallization was limited.

  4. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  5. Effect of rare earth Ce on the fatigue life of SnAgCu solder joints in WLCSP device using FEM and experiments

    International Nuclear Information System (INIS)

    Zhang, Liang; Han, Ji-guang; Guo, Yong-huan; He, Cheng-wen

    2014-01-01

    With the addition of 0.03 wt% rare earth Ce, in our previous works, the properties of SnAgCu solder were enhanced obviously. Based on the Garofalo–Arrhenius creep constitutive model, finite element method was used to simulate the stress–strain response during thermal cycle loading, and combined with the fatigue life prediction models, the fatigue life of SnAgCu/SnAgCuCe solder joints was calculated respectively, which can demonstrate the effect of the rare earth Ce on the fatigue life of SnAgCu solder joints. The results indicated that the maximum stress–strain can be found on the top surface of the corner solder joint, and the warpage of the PCB substrate occurred during thermal cycle loading. The trends obtained from modeling results have a good agreement with the experimental data reported in the literature for WLCSP devices. In addition, the stress–strain of SnAgCuCe solder joints is lower than that of SnAgCu solder joints. The thermal fatigue lives of solder joints calculated based on the creep model and creep strain energy density model show that the fatigue life of SnAgCuCe solder joints is higher than the SnAgCu solder joints. The fatigue life of SnAgCuCe solder joints can be enhanced significantly with the addition of Ce, is 30.2% higher than that of SnAgCu solder joints, which can be attributed to the CeSn 3 particles formed resisting the motion of dislocation; moreover, the refinement of microstructure and the IMC sizes also contribute to the enhancement of fatigue life, which elucidates that SnAgCuCe solder can be utilized in electronic industry with high reliability replacing the SnAgCu solder

  6. Effects of Amplitude Variations on Deformation and Damage Evolution in SnAgCu Solder in Isothermal Cycling

    Science.gov (United States)

    Wentlent, Luke; Alghoul, Thaer M.; Greene, Christopher M.; Borgesen, Peter

    2018-02-01

    Although apparently simpler than in thermal cycling, the behavior of SnAgCu (SAC) solder joints in cyclic bending or vibration is not currently well understood. The rate of damage has been shown to scale with the inelastic work per cycle, and excursions to higher amplitudes lead to an apparent softening, some of which remains so that damage accumulation is faster in subsequent cycling at lower amplitudes. This frequently leads to a dramatic breakdown of current damage accumulation rules. An empirical damage accumulation rule has been proposed to account for this, but any applicability to the extrapolation of accelerated test results to life under realistic long-term service conditions remains to be validated. This will require a better understanding of the underlying mechanisms. The present work provides experimental evidence to support recent suggestions that the observed behavior is a result of cycling-induced dislocation structures providing for increased diffusion creep. It is argued that this means that the measured work is an indicator of the instantaneous dislocation density, rather than necessarily reflecting the actual work involved in the creation of the damage.

  7. Paper microzone plates.

    Science.gov (United States)

    Carrilho, Emanuel; Phillips, Scott T; Vella, Sarah J; Martinez, Andres W; Whitesides, George M

    2009-08-01

    This paper describes 96- and 384-microzone plates fabricated in paper as alternatives to conventional multiwell plates fabricated in molded polymers. Paper-based plates are functionally related to plastic well plates, but they offer new capabilities. For example, paper-microzone plates are thin (approximately 180 microm), require small volumes of sample (5 microL per zone), and can be manufactured from inexpensive materials ($0.05 per plate). The paper-based plates are fabricated by patterning sheets of paper, using photolithography, into hydrophilic zones surrounded by hydrophobic polymeric barriers. This photolithography used an inexpensive formulation photoresist that allows rapid (approximately 15 min) prototyping of paper-based plates. These plates are compatible with conventional microplate readers for quantitative absorbance and fluorescence measurements. The limit of detection per zone loaded for fluorescence was 125 fmol for fluorescein isothiocyanate-labeled bovine serum albumin, and this level corresponds to 0.02 the quantity of analyte per well used to achieve comparable signal-to-noise in a 96-well plastic plate (using a solution of 25 nM labeled protein). The limits of detection for absorbance on paper was approximately 50 pmol per zone for both Coomassie Brilliant Blue and Amaranth dyes; these values were 0.4 that required for the plastic plate. Demonstration of quantitative colorimetric correlations using a scanner or camera to image the zones and to measure the intensity of color, makes it possible to conduct assays without a microplate reader.

  8. Radiation shielding lead shield

    International Nuclear Information System (INIS)

    Dei, Shoichi.

    1991-01-01

    The present invention concerns lead shields for radiation shielding. Shield boxes are disposed so as to surround a pipeline through which radioactive liquids, mists or like other objects are passed. Flanges are formed to each of the end edges of the shield boxes and the shield boxes are connected to each other by the flanges. Upon installation, empty shield boxes not charged with lead particles and iron plate shields are secured at first at the periphery of the pipeline. Then, lead particles are charged into the shield boxes. This attains a state as if lead plate corresponding to the depth of the box is disposed. Accordingly, operations for installation, dismantling and restoration can be conducted in an empty state with reduced weight to facilitate the operations. (I.S.)

  9. Effect of Surface Finish of Substrate on Mechanical Reliability of in-48SN Solder Joints in Moems Package

    OpenAIRE

    Koo, Ja-Myeong; Jung, Seung-Boo

    2007-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920); International audience; Interfacial reactions and shear properties of the In-48Sn (in wt.%) ball grid array (BGA) solder joints after bonding were investigated with four different surface finishes of the substrate over an underlying Cu pad: electroplated Ni/Au (hereafter E-NG), electroless Ni/immersion Au (hereafter ENIG), immersion Ag (hereafter I-Ag) and organic solderability preservative (hereafte...

  10. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    International Nuclear Information System (INIS)

    Koo, Jahyun; Lee, Changsoo; Hong, Sung Jea; Kim, Keun-Soo; Lee, Hyuck Mo

    2015-01-01

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu_3_3Al_1_7, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu_6Sn_5 networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu_6Sn_5 IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu_3_3Al_1_7 IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  11. A FPGA implementation of solder paste deposit on printed circuit boards errors detector based in a bright and contrast algorithm

    OpenAIRE

    De Luca-Pennacchia, A.; Sánchez-Martínez, M. Á.

    2007-01-01

    Solder paste deposit on printed circuit boards (PCB) is a critical stage. It is known that about 60% of functionality defects in this type of boards are due to poor solder paste printing. These defects can be diminished by means of automatic optical inspection of this printing. Actually, this process is implemented by image processing software with its inherent high computational time cost. In this paper we propose to implement a high parallel degree image comparison algorithm suitable to be ...

  12. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Jahyun; Lee, Changsoo [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Hong, Sung Jea [MK Electron Co., Ltd., Yongin Cheoin-gu 316-2 (Korea, Republic of); Kim, Keun-Soo, E-mail: keunsookim@hoseo.edu [Department of Display Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Hyuck Mo, E-mail: hmlee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-11-25

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu{sub 33}Al{sub 17}, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu{sub 6}Sn{sub 5} networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu{sub 6}Sn{sub 5} IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu{sub 33}Al{sub 17} IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  13. Pyramidal approach to license plate segmentation

    Science.gov (United States)

    Postolache, Alexandru; Trecat, Jacques C.

    1996-07-01

    Car identification is a goal in traffic control, transport planning, travel time measurement, managing parking lot traffic and so on. Most car identification algorithms contain a standalone plate segmentation process followed by a plate contents reading. A pyramidal algorithm for license plate segmentation, looking for textured regions, has been developed on a PC based system running Unix. It can be used directly in applications not requiring real time. When input images are relatively small, real-time performance is in fact accomplished by the algorithm. When using large images, porting the algorithm to special digital signal processors can easily lead to preserving real-time performance. Experimental results, for stationary and moving cars in outdoor scenes, showed high accuracy and high scores in detecting the plate. The algorithm also deals with cases where many character strings are present in the image, and not only the one corresponding to the plate. This is done by the means of a constrained texture regions classification.

  14. Intergranular stress corrosion in soldered joints of stainless steel 304

    International Nuclear Information System (INIS)

    Zamora R, L.

    1994-01-01

    The intergranular stress cracking of welded joints of austenitic stainless steel, AISI 304, is a serious problem in BWR type reactors. It is associated with the simultaneous presence of three factors; stress, a critical media and sensibilization (DOS). EPR technique was used in order to verify the sensibilization degree in the base metal, and the zone affected by heat and welding material. The characterization of material was done. The objective of this work is the study of microstructure and the evaluation of EPR technique used for the determination of DOS in a welded plate of austenitic stainless steel AISI 304. (Author)

  15. Effects of Ag addition on solid–state interfacial reactions between Sn–Ag–Cu solder and Cu substrate

    International Nuclear Information System (INIS)

    Yang, Ming; Ko, Yong-Ho; Bang, Junghwan; Kim, Taek-Soo; Lee, Chang-Woo; Li, Mingyu

    2017-01-01

    Low–Ag–content Sn–Ag–Cu (SAC) solders have attracted much recent attention in electronic packaging for their low cost. To reasonably reduce the Ag content in Pb–free solders, a deep understanding of the basic influence of Ag on the SAC solder/Cu substrate interfacial reaction is essential. Previous studies have discussed the influence of Ag on the interfacial intermetallic compound (IMC) thickness. However, because IMC growth is the joint result of multiple factors, such characterizations do not reveal the actual role of Ag. In this study, changes in interfacial IMCs after Ag introduction were systemically and quantitatively characterized in terms of coarsening behaviors, orientation evolution, and growth kinetics. The results show that Ag in the solder alloy affects the coarsening behavior, accelerates the orientation concentration, and inhibits the growth of interfacial IMCs during solid–state aging. The inhibition mechanism was quantitatively discussed considering the individual diffusion behaviors of Cu and Sn atoms, revealing that Ag inhibits interfacial IMC growth primarily by slowing the diffusion of Cu atoms through the interface. - Highlights: •Role of Ag in IMC formation during Sn–Ag–Cu soldering was investigated. •Ag affects coarsening, crystallographic orientation, and IMC growth. •Diffusion pathways of Sn and Cu are affected differently by Ag. •Ag slows Cu diffusion to inhibit IMC growth at solder/substrate interface.

  16. Effects of Ag addition on solid–state interfacial reactions between Sn–Ag–Cu solder and Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Ko, Yong-Ho [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Bang, Junghwan [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Kim, Taek-Soo [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Lee, Chang-Woo, E-mail: cwlee@kitech.re.kr [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Li, Mingyu, E-mail: myli@hit.edu.cn [Shenzhen Key Laboratory of Advanced Materials, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055 (China)

    2017-02-15

    Low–Ag–content Sn–Ag–Cu (SAC) solders have attracted much recent attention in electronic packaging for their low cost. To reasonably reduce the Ag content in Pb–free solders, a deep understanding of the basic influence of Ag on the SAC solder/Cu substrate interfacial reaction is essential. Previous studies have discussed the influence of Ag on the interfacial intermetallic compound (IMC) thickness. However, because IMC growth is the joint result of multiple factors, such characterizations do not reveal the actual role of Ag. In this study, changes in interfacial IMCs after Ag introduction were systemically and quantitatively characterized in terms of coarsening behaviors, orientation evolution, and growth kinetics. The results show that Ag in the solder alloy affects the coarsening behavior, accelerates the orientation concentration, and inhibits the growth of interfacial IMCs during solid–state aging. The inhibition mechanism was quantitatively discussed considering the individual diffusion behaviors of Cu and Sn atoms, revealing that Ag inhibits interfacial IMC growth primarily by slowing the diffusion of Cu atoms through the interface. - Highlights: •Role of Ag in IMC formation during Sn–Ag–Cu soldering was investigated. •Ag affects coarsening, crystallographic orientation, and IMC growth. •Diffusion pathways of Sn and Cu are affected differently by Ag. •Ag slows Cu diffusion to inhibit IMC growth at solder/substrate interface.

  17. Catalysts characteristics of Ni/YSZ core-shell according to plating conditions using electroless plating

    Science.gov (United States)

    Park, Hyun-Wook; Jang, Jae-Won; Lee, Young-Jin; Kim, Jin-Ho; Jeon, Dae-Woo; Lee, Jong-Heun; Hwang, Hae-jin; Lee, Mi-Jai

    2017-11-01

    This study aims to develop an anode catalyst for a solid oxide fuel cell (SOFC) using electroless nickel plating. We have proposed a new method for electroless plating of Ni metal on yttria-stabilized zirconia (YSZ) particles. We examine the uniformity of the Ni layer on the plated core-shell powder, in addition to the content of Ni and the reproducibility of the plating. We have also evaluated the carbon deposition rate and characteristics of the SOFC anode catalyst. To synthesize Ni-plated YSZ particles, the plated powder is heat-treated at 1200 °C. The resultant particles, which have an average size of 50 μm, were subsequently used in the experiment. The size of the Ni particles and the Ni content both increase with increasing plating temperature and plating time. The X-ray diffraction pattern reveals the growth of Ni particles. After heat-treatment, Ni is oxidized to NiO, leading to the co-existence of Ni and NiO; Ni3P is also observed due to the presence of phosphorous in the plating solution. Following heat treatment for 1 h at 1200 °C, Ni is mostly oxidized to NiO. The carbon deposition rate of the reference YSZ powder is 135%, while that of the Ni-plated YSZ is 1%-6%.

  18. Heavy gauge plates for nuclear application

    International Nuclear Information System (INIS)

    Cheviet, A.; Roux, J.-H.

    1977-01-01

    The production of energy from nuclear sources leads to the building of very large vessels working under pressure at elevated temperatures, requiring very thick steel plate (from 50 mm to 300 mm). The plates necessary for the production of these vessels have to be as large as possible in order to reduce the length of welds on the vessels. Those two requirements lead to the manufacture of heavy products from 10 to 80 tons unit weight. These products are special, because their fabrication requires very big facilities and also extremely high quality of the steel. The main points are: high cleanliness; properties as homogeneous as possible. The tests carried out on industrially produced plates (especially on a plate of 200 mm thick show the level of quality that can be reached [fr

  19. Biochemical effects of lead exposure and toxicity on battery manufacturing workers of Western Maharashtra (India): with respect to liver and kidney function tests

    OpenAIRE

    Mandakini Kshirsagar; Jyotsna Patil; Arun Patil; Ganesh Ghanwat; Ajit Sontakke; R.K. Ayachit

    2015-01-01

    Background: The battery recycling and manufacturing involves the use of metallic lead for making grids, bearing and solder. The process results in release of lead particles and lead oxide causing environmental pollution and severe lead poisoning. Aims and Objectives: To know the present scenario of the blood lead level and its biochemical effects on occupational lead-exposed population, mainly battery manufacturing workers in Western Maharashtra (India) with respect to liver and kidney functi...

  20. Solder bond requirement for large, built-up, high-performance conductors

    International Nuclear Information System (INIS)

    Willig, R.L.

    1981-01-01

    Some large built-up conductors fabricated for large superconducting magnets are designed to operate above the maximum recovery current. Because the stability of these conductors is sensitive to the quality of the solder bond joining the composite superconductor to the high-conductivity substrate, a minimum bond requirement is necessary. The present analysis finds that the superconductor is unstable and becomes abruptly resistive when there are temperature excursions into the current sharing region of a poorly bonded conductor. This abrupt transition, produces eddy current heating in the vicinity of the superconducting filaments and causes a sharp reduction in the minimum propagating zone (MPZ) energy. This sensitivity of the MPZ energy to the solder bond contact area is used to specify a minimum bond requirement. For the superconducting MHD magnet built for the Component Development Integration Facility (CDIF), the minimum bonded surface area is .68 cm/sup 2//cm which is 44% of the composite perimeter. 5 refs

  1. Appendix to the report from the low-residue soldering task force: Phase 2 results

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.; Anderson, D.J.; Huffman, D.D. [and others

    1995-12-01

    The LRSTF report for Phase I of its evaluation of low-residue soldering was issued in June 1995. This Appendix summarizes the results of follow-on testing performed in Phase II and compares electrical test results for both phases. Deliberate decisions were made by the LRSTF in Phase I to challenge the design guideline limits in MILSTD-275, Printed Wiring for Electronic Equipment The LRSTF considered this approach to produce a ``worst case`` design and provide useful information about the robustness of LR soldering processes. As such, good design practices were sometimes deliberately violated in designing the LRSTF board. This approach created some anomalies for both LR boards and RMA/cleaned controls. Phase II testing verified that problems that affected both RMA/cleaned and LR boards in Phase I were design related.

  2. Diode Lasers used in Plastic Welding and Selective Laser Soldering - Applications and Products

    Science.gov (United States)

    Reinl, S.

    Aside from conventional welding methods, laser welding of plastics has established itself as a proven bonding method. The component-conserving and clean process offers numerous advantages and enables welding of sensitive assemblies in automotive, electronic, medical, human care, food packaging and consumer electronics markets. Diode lasers are established since years within plastic welding applications. Also, soft soldering using laser radiation is becoming more and more significant in the field of direct diode laser applications. Fast power controllability combined with a contactless temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. These advantages come in to full effect when soldering of increasingly small parts in temperature sensitive environments is necessary.

  3. Effects of In and Ni Addition on Microstructure of Sn-58Bi Solder Joint

    Science.gov (United States)

    Mokhtari, Omid; Nishikawa, Hiroshi

    2014-11-01

    In this study, the effect of adding 0.5 wt.% and 1 wt.% In and Ni to Sn-58Bi solder on intermetallic compound (IMC) layers at the interface and the microstructure of the solder alloys were investigated during reflow and thermal aging by scanning electron microscopy and electron probe micro-analysis. The results showed that the addition of minor elements was not effective in suppressing the IMC growth during the reflow; however, the addition of 0.5 wt.% In and Ni was effective in suppressing the IMC layer growth during thermal aging. The thickening kinetics of the total IMC layer was analyzed by plotting the mean thickness versus the aging time on log-log coordinates, and the results showed the transition point from grain boundary diffusion control to a volume diffusion control mechanism. The results also showed that the minor addition of In can significantly suppress the coarsening of the Bi phase.

  4. Oxidation and reduction kinetics of eutectic SnPb, InSn, and AuSn: a knowledge base for fluxless solder bonding applications

    DEFF Research Database (Denmark)

    Kuhmann, Jochen Friedrich; Preuss, A.; Adolphi, B.

    1998-01-01

    : (1) SnPb; (2) InSn; (3) AuSn. The studies of the oxidation kinetics show that the growth of the native oxide, which covers the solder surfaces from the start of all soldering operations is self-limiting. The rate of oxidation on the molten, metallic solder surfaces is significantly reduced...... and reduction kinetics, are applied to flip-chip (FC) bonding experiments in vacuum with and without the injection of H2. Wetting in vacuum is excellent but the self-alignment during flip-chip soldering is restricted. The desired, perfectly self-aligned FC-bonds have been only achieved, using evaporated...

  5. LEADING WITH LEADING INDICATORS

    International Nuclear Information System (INIS)

    PREVETTE, S.S.

    2005-01-01

    This paper documents Fluor Hanford's use of Leading Indicators, management leadership, and statistical methodology in order to improve safe performance of work. By applying these methods, Fluor Hanford achieved a significant reduction in injury rates in 2003 and 2004, and the improvement continues today. The integration of data, leadership, and teamwork pays off with improved safety performance and credibility with the customer. The use of Statistical Process Control, Pareto Charts, and Systems Thinking and their effect on management decisions and employee involvement are discussed. Included are practical examples of choosing leading indicators. A statistically based color coded dashboard presentation system methodology is provided. These tools, management theories and methods, coupled with involved leadership and employee efforts, directly led to significant improvements in worker safety and health, and environmental protection and restoration at one of the nation's largest nuclear cleanup sites

  6. Current redistribution in cables made of insulated, soldered, or oxidized strands

    International Nuclear Information System (INIS)

    Turck, B.

    1979-07-01

    Current redistributions are compared in cables made of insulated strands, soldered, or oxidized strands and insulated strands with periodic joints. After discussing the different current redistributions in the cases of a rapidly changing current and a dc current, several particular situations are investigated: what happens if a strand is broken, or if a local normal zone appears that does not affect all the strands equally, the detection of this normal zone, and the influence of short circuits between strands

  7. Home Plumbing Simulator for the Study of Copper and Lead Corrosion and Release, Disinfectant Demand, and Biofilm Activity - abstract

    Science.gov (United States)

    The corrosion of household or premise plumbing materials (such as copper, brass, and solder) and the metal release that results from that corrosion can cause numerous problems, ranging from “blue” water to copper pinhole leaks. If left untreated, these problems can lead to health...

  8. Create Your Plate

    Medline Plus

    Full Text Available ... Type 2 Diabetes Know Your Rights Employment Discrimination Health Care Professionals Law ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart- ...

  9. Create Your Plate

    Medline Plus

    Full Text Available ... Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday ... Carbohydrates Types of Carbohydrates Carbohydrate Counting Make Your Carbs ...

  10. Anterior cervical fusion: the role of anterior plating.

    Science.gov (United States)

    Daffner, Scott D; Wang, Jeffrey C

    2009-01-01

    Treatment of cervical pathology requires a clear understanding of the biomechanical benefits and limitations of cervical plates, their indications, and their associated complications. The use of anterior cervical plates has evolved significantly since their early application in cervical trauma. They have become widely used for anterior cervical decompression and fusion for cervical spondylosis. Plate design has undergone significant refinement and innovation, from the initial unlocked plates requiring bicortical purchase to the latest rotationally and translationally semiconstrained dynamic plates. Excellent clinical results have been reported for single-level anterior cervical decompression and fusion with or without plate fixation; however, the addition of an anterior cervical plate clearly leads to earlier fusion and better clinical results in longer fusions. Longer fusions should ideally consist of corpectomies and strut grafting because the decreased number of fusion surfaces tends to lead to higher fusion rates. Although anterior plate fixation leads to higher fusion rates in fusions of three or more levels, the associated pseudarthrosis rate is still high. The use of dynamic plates, through increased load sharing across the graft and decreased stress shielding, may improve fusion rates, particularly in long fusions. Nevertheless, adjuvant posterior fixation is recommended for fusions of more than three vertebral levels. Anterior plate fixation may be of particular benefit in the management of traumatic injuries, in revision settings, and in the treatment of smokers. Complications unique to plate fixation include hardware breakage and migration as well as ossification of the adjacent disk levels.

  11. Evaluation on Dorsey Method in Surface Tension Measurement of Solder Liquids Containing Surfactants

    Science.gov (United States)

    Zhao, Xingke; Xie, Feiming; Fan, Jinsheng; Liu, Dayong; Huang, Jihua; Chen, Shuhai

    2018-06-01

    With the purpose of developing a feasible approach for measuring the surface tension of solders containing surfactants, the surface tension of Sn-3Ag-0.5Cu-xP solder alloys, with various drop sizes as well as different phosphorus (P) content, was evaluated using the Dorsey method based on the sessile drop test. The results show that the accuracy of the surface tension calculations depends on both of sessile drop size and the liquid metal composition. With a proper drop size, in the range of 4.5 mm to 5.3 mm in equivalent spherical diameters, the deviation of the surface tension calculation can be limited to 1.43 mN·m-1 and 6.30 mN·m-1 for SnAgCu and SnAgCu-P, respectively. The surface tension of SnAgCu-xP solder alloys decreases quickly to a minimum value when the P content reaches 0.5 wt% and subsequently increases slowly with the P content further increasing. The formation of a P-enriched surface layer and Sn4P3 intermetallic phases is regarded to be responsible for the decreasing and subsequent increasing of surface tension, respectively.

  12. Liver repair and hemorrhage control by using laser soldering of liquid albumin in a porcine model.

    Science.gov (United States)

    Wadia, Y; Xie, H; Kajitani, M

    2000-01-01

    We evaluated laser soldering by using liquid albumin for welding liver injuries. Major liver trauma has a high mortality because of immediate exsanguination and a delayed morbidity from septicemia, peritonitis, biliary fistulae, and delayed secondary hemorrhage. Eight laceration (6 x 2 cm) and eight nonanatomic resection injuries (raw surface, 6 x 2 cm) were repaired. An 805-nm laser was used to weld 50% liquid albumin-indocyanine green solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized and hepatic inflow occlusion was used for vascular control. All 16 soldering repairs were evaluated at 3 hours. All 16 laser mediated liver repairs had minimal blood loss as compared with the suture controls. No dehiscence, hemorrhage, or bile leakage was seen in any of the laser repairs after 3 hours. Laser fusion repair of the liver is a reliable technique to gain hemostasis on the raw surface as well as weld lacerations. Copyright 2000 Wiley-Liss, Inc.

  13. Investigation of Sn-Pb solder bumps of prototype photo detectors for the LHCb experiment

    CERN Document Server

    Delsante, M L; Arnau-Izquierdo, G

    2004-01-01

    The Large Hadron Collider (LHC) is now under construction at the European Organization for Nuclear Research (CERN). LHCb is one of the dedicated LHC experiments, allowing high energy proton-proton collisions to be exploited. This paper presents the results of the metallurgic studies carried out on Sn-Pb solder bumps of prototype vacuum photo detectors under development for LHCb, and in particular for the ring imaging Cherenkov-hybrid photo diode (RICH-HPD) project. These detectors encapsulate, in a vacuum tube, an assembly made of two silicon chips bonded together by a matrix of solder bumps. Each bump lies on a suitable system of under-bump metallic layers ensuring mechanical and electrical transition between the chip pad and the solder alloy. During manufacturing of the detector, bump-bonded (BB) assemblies are exposed to severe heat cycles up to 400 degree C inducing, in the present fabrication process, a clear degradation of electrical connectivity. Several investigations such as microstructural observati...

  14. Multi-layer SiC ceramics/Mo joints brazed using high-temperature solders

    International Nuclear Information System (INIS)

    Olesinska, W.; Kesik, J.

    2003-01-01

    The paper presents the results of studies on joining SiC ceramics with molybdenum, with the ceramic surface being activated by titanium, chromium or copper. Titanium or chromium were deposited by the sputtering technique, and copper - by the electro-chemical method. The microstructures of the SiC/Mo joints brazed with the CuMn13Ni3 solder and copper in a nitrogen atmosphere were examined and the results discussed. The joints, in which the ceramic surface was activated in addition with chromium, do not contain mechanical defects caused by the joining process, and the ceramic surface is covered with a continuous layer of the solder. A phase analysis of the interface surface identified an MeSiC phase. The mechanical strength of the joints in which the ceramic surface was modified by the Ti, Cr and Cu layers was markedly greater than that of the joints brazed directly to the uncoated ceramics with the use of active solders. (author)

  15. Laser Soldering and Thermal Cycling Tests of Monolithic Silicon Pixel Chips

    CERN Document Server

    Strand, Frode Sneve

    2015-01-01

    An ALPIDE-1 monolithic silicon pixel sensor prototype has been laser soldered to a flex printed circuit using a novel interconnection technique using lasers. This technique is to be optimised to ensure stable, good quality connections between the sensor chips and the FPCs. To test the long-term stability of the connections, as well as study the effects on hit thresholds and noise in the sensor, it was thermally cycled in a climate chamber 1200 times. The soldered connections showed good qualities like even melting and good adhesion on pad/flex surfaces, and the chip remained in working condition for 1080 cycles. After this, a few connections failed, having cracks in the soldering tin, rendering the chip unusable. Threshold and noise characteristics seemed stable, except for the noise levels of sector 2 in the chip, for 1000 cycles in a temperature interval of "10^{\\circ}" and "50^{\\circ}" C. Still, further testing with wider temperature ranges and more cycles is needed to test the limitations of the chi...

  16. Reinforcement of high-risk anastomoses using laser-activated protein solders: a clinical study

    Science.gov (United States)

    Libutti, Steven K.; Bessler, Marc; Chabot, J.; Bass, Lawrence S.; Oz, Mehmet C.; Auteri, Joseph S.; Kirsch, Andrew J.; Nowygrod, Roman; Treat, Michael R.

    1993-07-01

    Anastomotic leakage or breakdown can result in catastrophic complications and significantly increased post-operative morbidity and mortality. Certain anastomoses are subject to a higher incidence of disruption and are therefore termed high risk. In an attempt to decrease the risk of anastomotic leaks, we reinforced sutured anastomoses with a laser activated protein solder in patients undergoing esophagojejunostomies (n equals 2), lung transplantation (n equals 2), and pancreaticojejunostomies (Whipple procedure, n equals 5). The protein solder was composed of 1.0 ml of a 25% human albumin solution, 1.0 ml of sodium hyaluronate, and 0.1 ml of Cardiogreen dye. This composition was applied to the sutured anastomosis and activated with an 860 nm pulsed diode laser. Drains were placed when appropriate and patients were followed for up to 10 months post-operatively and assessed for clinical signs of anastomotic leaks. Results to data demonstrated that there were no immediate complications as a result of the procedure. Operative time was not significantly lengthened. There were no cases of clinically significant leakage from any of the reinforced anastomoses. Laser activated protein solders may help to reduce the incidence of leakage in high risk anastomoses. Large numbers of patients and longer follow-up is needed however, to draw significant conclusions.

  17. Liver repair and hemorrhage control using laser soldering of liquid albumin in a porcine model

    Science.gov (United States)

    Wadia, Yasmin; Xie, Hua; Kajitani, Michio; Gregory, Kenton W.; Prahl, Scott A.

    2000-05-01

    The purpose of this study was to evaluate laser soldering using liquid albumin for welding liver lacerations and sealing raw surfaces created by segmental resection of a lobe. Major liver trauma has a high mortality due to immediate exsanguination and a delayed morbidity and mortality from septicemia, peritonitis, biliary fistulae and delayed secondary hemorrhage. Eight laceration injuries (6 cm long X 2 cm deep) and eight non-anatomical resection injuries (raw surface 6 cm X 2 cm) were repaired. An 805 nm laser was used to weld 53% liquid albumin-ICG solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized to simulate coagulation failure and hepatic inflow occlusion was used for vascular control. For both laceration and resection injuries, eight soldering repairs each were evaluated at three hours. A single suture repair of each type was evaluated at three hours. All 16 laser mediated liver repairs were accompanied by minimal blood loss as compared to the suture controls. No dehiscence, hemorrhage or bile leakage was seen in any of the laser repairs after three hours. In conclusion laser fusion repair of the liver is a quick and reliable technique to gain hemostasis on the cut surface as well as weld lacerations.

  18. Dissolution and uptake of cadmium from dental gold solder alloy implants

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, B; Bergman, M; Soeremark, R [Umeaa Univ. (Sweden); Karolinska Institutet, Stockholm (Sweden))

    1977-01-01

    Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium (/sup 115/Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3 d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of /sup 115/Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver.

  19. Mathematical methods for elastic plates

    CERN Document Server

    Constanda, Christian

    2014-01-01

    Mathematical models of deformation of elastic plates are used by applied mathematicians and engineers in connection with a wide range of practical applications, from microchip production to the construction of skyscrapers and aircraft. This book employs two important analytic techniques to solve the fundamental boundary value problems for the theory of plates with transverse shear deformation, which offers a more complete picture of the physical process of bending than Kirchhoff’s classical one.   The first method transfers the ellipticity of the governing system to the boundary, leading to singular integral equations on the contour of the domain. These equations, established on the basis of the properties of suitable layer potentials, are then solved in spaces of smooth (Hölder continuous and Hölder continuously differentiable) functions.   The second technique rewrites the differential system in terms of complex variables and fully integrates it, expressing the solution as a combination of complex ana...

  20. Is There Really A North American Plate?

    Science.gov (United States)

    Krill, A.

    2011-12-01

    Lithospheric plates are typically identified from earthquake epicenters and evidence such as GPS movements. But no evidence indicates a plate boundary between the North American and South American Plates. Some plate maps show them separated by a transform boundary, but it is only a fracture zone. Other maps show an "undefined plate boundary" or put no boundary between these two plates (check Google images). Early plate maps showed a single large American Plate, quite narrow east of the Caribbean Plate (Le Pichon 1968, Morgan 1968). The North and South American Plates became established by the leading textbook Earth (Press & Siever 1974). On their map, from a Scientific American article by John Dewey (1972), these new plates were separated by an "uncertain plate boundary." The reasons for postulating a North American Plate were probably more psychological than geological. Each of the other continents of the world had its own plate, and North American geologists naturally wanted theirs. Similarly, European geographers used to view Europe as its own continent. A single large plate should again be hypothesized. But the term American Plate would now be ambiguous ("Which plate, North or South?") Perhaps future textbook authors could call it the "Two-American Plate." Textbook authors ultimately decide such global-tectonic matters. I became aware of textbook authors' opinions and influence from my research into the history of Alfred Wegener's continental drift (see Fixists vs. Mobilists by Krill 2011). Leading textbook author Charles Schuchert realized that continental drift would abolish his cherished paleogeographic models of large east-west continents (Eria, Gondwana) and small oceans (Poseiden, Nereis). He and his junior coauthors conspired to keep drift evidence out of their textbooks, from the 1934-editions until the 1969-editions (Physical Geology by Longwell et al. 1969, Historical Geology by Dunbar & Waage 1969). Their textbooks ruled in America. Textbooks

  1. Create Your Plate

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Create Your Plate Create Your Plate is a ...

  2. Create Your Plate

    Medline Plus

    Full Text Available ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart- ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods ...

  4. Create Your Plate

    Medline Plus

    Full Text Available ... ready, you can try new foods within each food category. Try these seven steps to get started: Using your dinner plate, put a line down the middle of the plate. Then on one side, cut it ... and starchy foods. See this list of grains and starchy foods . ...

  5. Effects of Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} intermetallic layers on cross-interaction between Pd and Ni in solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Yong-Ho [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Chung, Bo-Mook [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Department of Research and Development, KPM TECH, Ansan 425-090 (Korea, Republic of); Choi, Young-Sik [Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Choi, Jaeho [Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Huh, Joo-Youl, E-mail: jyhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2013-12-05

    Highlights: •Ni{sub 3}Sn{sub 4} acts as a source of Ni atoms, leading to a strong cross-interaction with Pd. •(Cu,Ni){sub 6}Sn{sub 5} is an effective Ni diffusion barrier, inhibiting Pd resettlement. •Dissolution kinetics of (Pd,Ni)Sn{sub 4} was interpreted based on the Sn–Ni–Pd isotherm. •Cu addition to solder alleviates the (Pd,Ni)Sn{sub 4}-related risk of reliability deterioration. -- Abstract: We examined the effects of layers of intermetallic compound (IMC) Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} formed at the solder/Ni interface, on the cross-interactions between Pd and Ni during solid-state aging and reflow soldering. Two types of diffusion couples, Pd/Sn/Ni and Pd/Sn–Cu/Ni, were aged at 150 °C to study the solid-state interactions. In contrast to the Pd/Sn/Ni couples in which a Ni{sub 3}Sn{sub 4} layer formed at the Ni interface, the Pd/Sn–Cu/Ni couple where a (Cu,Ni){sub 6}Sn{sub 5} layer formed at the Ni interface exhibited no significant interaction between Pd and Ni. The (Cu,Ni){sub 6}Sn{sub 5} layer acted as an effective barrier against Ni diffusion and thus inhibited the resettlement of (Pd,Ni)Sn{sub 4} onto the Ni interface. For the interaction during reflow, Sn–3.5Ag and Sn–3.0Ag–0.5Cu solder balls were isothermally reflowed on an electroless Ni(P)/electroless Pd/immersion Au (ENEPIG) surface finish at 250 °C, and the dissolution kinetics of the (Pd,Ni)Sn{sub 4} particles converted from the 0.2-μm-thick Pd-finish layer were examined. The spalled (Pd,Ni)Sn{sub 4} particles very quickly dissolved into the molten solder when the IMC layer formed on the Ni substrate was (Cu,Ni){sub 6}Sn{sub 5} rather than Ni{sub 3}Sn{sub 4}. The dependence of the dissolution kinetics of the spalled (Pd,Ni)Sn{sub 4} particles on the IMC layers was rationalized on the basis of a Sn–Ni–Pd isotherm at 250 °C. The present study suggests that the formation of a dense (Cu,Ni){sub 6}Sn{sub 5} layer at the solder/Ni interface can effectively

  6. Towards stacked zone plates

    International Nuclear Information System (INIS)

    Werner, S; Rehbein, S; Guttman, P; Heim, S; Schneider, G

    2009-01-01

    Fresnel zone plates are the key optical elements for soft and hard x-ray microscopy. For short exposure times and minimum radiation load of the specimen the diffraction efficiency of the zone plate objectives has to be maximized. As the efficiency strongly depends on the height of the diffracting zone structures the achievable aspect ratio of the nanostructures determines these limits. To reach aspect ratios ≥ 20:1 for high efficient optics we propose to superimpose zone plates on top of each other. With this multiplication approach the final aspect ratio is only limited by the number of stacked zone plate layers. For the stack process several nanostructuring process steps have to be developed and/or improved. Our results show for the first time two layers of zone plates stacked on top of each other.

  7. Thermal conductivity measurement of HTS tapes and stacks for current lead applications

    International Nuclear Information System (INIS)

    Schwarz, Michael; Weiss, Klaus-Peter; Heller, Reinhard; Fietz, Walter H.

    2009-01-01

    The use of high-temperature-superconductors (HTS) within current leads offers a high potential to save cooling-power. The principle of HTS current leads is well established, e.g. for particle accelerators (LHC-CERN) but also on the commercial sector, which offer HTS current leads ready for use in small scale magnets and magnets systems. Future fusion machines currently under construction like ITER, W7-X or JT-60SA also will use HTS current leads. At the moment the standard material for HTS current leads is a Bi 2 Sr 2 Ca 2 Cu 3 O x (BSCCO)-AgAu composite tape. The common way to receive high current capacity current leads is to form stacks by sintering or soldering these tapes together. The solder changes the thermal conductivity of the stacks compared to the single tape in the temperature range from 4 K to 60 K. To estimate the heat flux from the warm environment to the cold application the measurement of the thermal conductivity of the soldered stack is mandatory. Therefore the thermal conductivity of stacks with different number of tapes is investigated. To measure the thermal conduction in the current flow direction, the axial heat flow method is used. Combining these results with FEM simulations gives the possibility to estimate the thermal conductivity normal to the flat tape plane. The resulting anisotropic thermal conductivity can be used to model the behaviour of the HTS tape under thermal disturbances more accurately.

  8. A Possible Differentially Shortened Strike-slip Plate Boundary: the Okhotsk Plate Example.

    Science.gov (United States)

    Hindle, D.; Egorov, V.; Mackey, K. G.; Fujita, K.

    2004-12-01

    The Okhotsk plate has been postulated based on a combination of GPS geodetic inversions (REVEL1), seimsicity, geologic and lineament data. Lying between the North American and Eurasian plates, its northwestern corner would appear to be undergoing compression in a scissors motion between the two bounding plates. Extrusion tectonics along multiple, large strike-slip faults within the Okhotsk plate itself have been suggested to allow the escape of material away from the apex of Eurasia-North America. The plate boundary between Okhotsk and North America has been suggested to be diffuse, based on widely scattered minor seismicity. However, the large, left lateral, Ulakhan fault has also been suggested as a candidate plate boundary. We present field geological and geomorphological evidence of the partitioning of deformation between the Ulakhan fault, and several parallel and oblique, linked faults. The Ulakhan fault strand appears to have a maximum displacement of 24 km based on river valley offsets and closing large pull apart basins. Some of the displacement from the Ulakhan fault appears relayed into the plate margin along oblique trending, thrust/oblique slip faults. Estimated shortening over these faults is equivalent to the amount of shortening relayed into the plate margin from the plate boundary. There may be several thrust/oblique slip faults along the Ulakhan fault, which leads to the interesting situation of a segmented, strike-slip plate boundary being actively shortened in a margin parallel direction. This may be the result of postulated extrusion of the Okhotsk plate due to North America/Eurasia convergence. Such a situation would have important consequences for the interpretation of GPS data in a plate tectonic context.

  9. Interfacial Reaction and IMC Growth of an Ultrasonically Soldered Cu/SAC305/Cu Structure during Isothermal Aging

    Directory of Open Access Journals (Sweden)

    Yulong Li

    2018-01-01

    Full Text Available In order to accelerate the growth of interfacial intermetallic compound (IMC layers in a soldering structure, Cu/SAC305/Cu was first ultrasonically spot soldered and then subjected to isothermal aging. Relatively short vibration times, i.e., 400 ms and 800 ms, were used for the ultrasonic soldering. The isothermal aging was conducted at 150 °C for 0, 120, 240, and 360 h. The evolution of microstructure, the IMC layer growth mechanism during aging, and the shear strength of the joints after aging were systemically investigated. Results showed the following. (i Formation of intermetallic compounds was accelerated by ultrasonic cavitation and streaming effects, the thickness of the interfacial Cu6Sn5 layer increased with aging time, and a thin Cu3Sn layer was identified after aging for 360 h. (ii The growth of the interfacial IMC layer of the ultrasonically soldered Cu/SAC305/Cu joints followed a linear function of the square root of the aging time, revealing a diffusion-controlled mechanism. (iii The tensile shear strength of the joint decreased to a small extent with increasing aging time, owing to the combined effects of IMC grain coarsening and the increase of the interfacial IMC. (iv Finally, although the fracture surfaces and failure locations of the joint soldered with 400 ms and 800 ms vibration times show similar characteristics, they are influenced by the aging time.

  10. Comparative Study of ENIG and ENEPIG as Surface Finishes for a Sn-Ag-Cu Solder Joint

    Science.gov (United States)

    Yoon, Jeong-Won; Noh, Bo-In; Jung, Seung-Boo

    2011-09-01

    Interfacial reactions and joint reliability of Sn-3.0Ag-0.5Cu solder with two different surface finishes, electroless nickel-immersion gold (ENIG) and electroless nickel-electroless palladium-immersion gold (ENEPIG), were evaluated during a reflow process. We first compared the interfacial reactions of the two solder joints and also successfully revealed a connection between the interfacial reaction behavior and mechanical reliability. The Sn-Ag-Cu/ENIG joint exhibited a higher intermetallic compound (IMC) growth rate and a higher consumption rate of the Ni(P) layer than the Sn-Ag-Cu/ENEPIG joint. The presence of the Pd layer in the ENEPIG suppressed the growth of the interfacial IMC layer and the consumption of the Ni(P) layer, resulting in the superior interfacial stability of the solder joint. The shear test results show that the ENIG joint fractured along the interface, exhibiting indications of brittle failure possibly due to the brittle IMC layer. In contrast, the failure of the ENEPIG joint only went through the bulk solder, supporting the idea that the interface is mechanically reliable. The results from this study confirm that the Sn-Ag-Cu/ENEPIG solder joint is mechanically robust and, thus, the combination is a viable option for a Pb-free package system.

  11. CO2 temperature-controlled laser soldering of pig trachea incisions in vitro using flexible albumin bands

    Science.gov (United States)

    Sharvit, Dan; Vasilyev, Tamar; Vasserman, Irena; Simhon, David; Kariv, Naam; DeRowe, Ari; Katzir, Abraham

    2005-04-01

    Resection of a segment of the trachea is a procedure applied for the removal of cervical tumors invading the trachea, or for the treatment of severe tracheal stenosis. The current method of anastomosis is based on multiple sutures. The main drawbacks of this method are: 1) A long procedure time, 2) An air leakage, and 3) An inflammatory response to the sutures. In this study we evaluated the feasibility and effectiveness of the use of temperature controlled CO2 laser soldering of incisions in pig tracheas in vitro. A transverse incision was made in a separated pig trachea. A flexible albumin band was prepared and was laser soldered with albumin solder to the outer surface of the trachea, covering the incision. The soldered trachea ends were sealed and the burst pressure was measured. In a series of in vitro experiments, the mean burst pressure was found to be 230 mm Hg. These preliminary results demonstrated that laser soldering using a flexible albumin band may be a useful method for sealing an incision in the trachea.

  12. Electrical Resistance of Nb$_{3}$Sn/Cu Splices Produced by Electromagnetic Pulse Technology and Soft Soldering

    CERN Document Server

    Schoerling, D; Scheuerlein, C; Atieh, S; Schaefer, R

    2011-01-01

    The electrical interconnection of Nb$_{3}$Sn/Cu strands is a key issue for the construction of Nb$_{3}$Sn based damping ring wigglers and insertion devices for third generation light sources. We compare the electrical resistance of Nb$_{3}$Sn/Cu splices manufactured by solid state welding using Electromagnetic Pulse Technology (EMPT) with that of splices produced by soft soldering with two different solders. The resistance of splices produced by soft soldering depends strongly on the resistivity of the solder alloy at the operating temperature. By solid state welding splice resistances below 10 nOhm can be achieved with 1 cm strand overlap length only, which is about 4 times lower than the resistance of Sn96Ag4 soldered splices with the same overlap length. The comparison of experimental results with Finite Element simulations shows that the electrical resistance of EMPT welded splices is determined by the resistance of the stabilizing copper between the superconducting filaments and confirms that welding of ...

  13. Development of Sn-Ag-Cu-X Solders for Electronic Assembly by Micro-Alloying with Al

    Science.gov (United States)

    Boesenberg, Adam J.; Anderson, Iver E.; Harringa, Joel L.

    2012-07-01

    Of Pb-free solder choices, an array of solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic ( T eut = 217°C) composition have emerged with potential for broad use, including ball grid array (BGA) joints that cool slowly. This work investigated minor substitutional additions of Al (0.05Al), but the suppression effect faded for >0.20Al. Undercooling suppression did not correlate specifically with blade suppression since it became significant at 0.10Al and increased continuously with greater Al to 0.25Al. Surprisingly, an intermediate range of Al content (0.10 wt.% to 0.20 wt.% Al) promoted formation of significant populations of 2- μm to 5- μm faceted Cu-Al particles, identified as Cu33Al17, that clustered at the top of the solder joint matrix and exhibited extraordinary hardness. Clustering of Cu33Al17 was attributed to its buoyancy, from a lower density than Sn liquid, and its early position in the nucleation sequence within the solder matrix, permitting unrestricted migration to the top interface. Joint microstructures and implications for the full nucleation sequence for these SAC + Al solder joints are discussed, along with possible benefits from the clustered particles for improved thermal cycling resistance.

  14. Vortex Dynamics around Pitching Plates

    Science.gov (United States)

    2014-04-29

    electrical signals are A/D converted in an ATI NetBox interface and recorded using a Java application, and are filtered in three steps. The first is a low...the plate while staying attached to the corners of the leading edge. During this process, a second vortex loop, created by the quick angular ...is a spike in CL centered around t = 0 due to non-circulatory6 effects from the angular acceleration of the wing. The amplitude of the peak is

  15. Stability of molybdenum nanoparticles in Sn-3.8Ag-0.7Cu solder during multiple reflow and their influence on interfacial intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Arafat, M.M., E-mail: arafat_mahmood@yahoo.com; Johan, Mohd Rafie, E-mail: mrafiej@um.edu.my

    2012-02-15

    This work investigates the effects of molybdenum nanoparticles on the growth of interfacial intermetallic compound between Sn-3.8Ag-0.7Cu solder and copper substrate during multiple reflow. Molybdenum nanoparticles were mixed with Sn-3.8Ag-0.7Cu solder paste by manual mixing. Solder samples were reflowed on a copper substrate in a 250 Degree-Sign C reflow oven up to six times. The molybdenum content of the bulk solder was determined by inductive coupled plasma-optical emission spectrometry. It is found that upon the addition of molybdenum nanoparticles to Sn-3.8Ag-0.7Cu solder, the interfacial intermetallic compound thickness and scallop diameter decreases under all reflow conditions. Molybdenum nanoparticles do not appear to dissolve or react with the solder. They tend to adsorb preferentially at the interface between solder and the intermetallic compound scallops. It is suggested that molybdenum nanoparticles impart their influence on the interfacial intermetallic compound as discrete particles. The intact, discrete nanoparticles, by absorbing preferentially at the interface, hinder the diffusion flux of the substrate and thereby suppress the intermetallic compound growth. - Highlights: Black-Right-Pointing-Pointer Mo nanoparticles do not dissolve or react with the SAC solder during reflow. Black-Right-Pointing-Pointer Addition of Mo nanoparticles results smaller IMC thickness and scallop diameter. Black-Right-Pointing-Pointer Mo nanoparticles influence the interfacial IMC through discrete particle effect.

  16. Development of Bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

    Science.gov (United States)

    Takaku, Yoshikazu; Ohnuma, Ikuo; Kainuma, Ryosuke; Yamada, Yasushi; Yagi, Yuji; Nishibe, Yuji; Ishida, Kiyohito

    2006-11-01

    Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573 583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X=Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint.

  17. Anisotropic elastic plates

    CERN Document Server

    Hwu, Chyanbin

    2010-01-01

    As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a

  18. High loading uranium plate

    International Nuclear Information System (INIS)

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process

  19. Microstructural effects on constitutive and fatigue fracture behavior of TinSilverCopper solder

    Science.gov (United States)

    Tucker, Jonathon P.

    As microelectronic package construction becomes more diverse and complex, the need for accurate, geometry-independent material constitutive and failure models increases. Evaluations of packages based on accelerated environmental tests (such as accelerated thermal cycling or power cycling) only provide package-dependent reliability information. In addition, extrapolations of such test data to life predictions under field conditions are often empirical. Besides geometry, accelerated environmental test data must account for microstructural factors such as alloy composition or isothermal aging condition, resulting in expensive experimental variation. In this work, displacement-controlled, creep, and fatigue lap shear tests are conducted on specially designed SnAgCu test specimens with microstructures representative to those found in commercial microelectronic packages. The data are used to develop constitutive and fatigue fracture material models capable of describing deformation and fracture behavior for the relevant temperature and strain rate ranges. Furthermore, insight is provided into the microstructural variation of solder joints and the subsequent effect on material behavior. These models are appropriate for application to packages of any geometrical construction. The first focus of the thesis is on Pb-mixed SnAgCu solder alloys. During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of SnPb and SnAgCu often result from either mixed assemblies or rework. Three alloys of 1, 5 and 20 weight percent Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn37Pb components mixed with Sn3.0Ag0.5Cu. Displacement-controlled (constant strain rate) and creep tests were performed at temperatures of 25°C, 75°C, and 125°C using a double lap shear test setup that ensures a nearly homogeneous state of plastic strain at the joint interface. Rate-dependent constitutive models for Pb

  20. Subduction Drive of Plate Tectonics

    Science.gov (United States)

    Hamilton, W. B.

    2003-12-01

    Don Anderson emphasizes that plate tectonics is self-organizing and is driven by subduction, which rights the density inversion generated as oceanic lithosphere forms by cooling of asthenosphere from the top. The following synthesis owes much to many discussions with him. Hinge rollback is the key to kinematics, and, like the rest of actual plate behavior, is incompatible with bottom-up convection drive. Subduction hinges (which are under, not in front of, thin leading parts of arcs and overriding plates) roll back into subducting plates. The Pacific shrinks because bounding hinges roll back into it. Colliding arcs, increasing arc curvatures, back-arc spreading, and advance of small arcs into large plates also require rollback. Forearcs of overriding plates commonly bear basins which preclude shortening of thin plate fronts throughout periods recorded by basin strata (100 Ma for Cretaceous and Paleogene California). This requires subequal rates of advance and rollback, and control of both by subduction. Convergence rate is equal to rates of rollback and advance in many systems but is greater in others. Plate-related circulation probably is closed above 650 km. Despite the popularity of concepts of plumes from, and subduction into, lower mantle, there is no convincing evidence for, and much evidence against, penetration of the 650 in either direction. That barrier not only has a crossing-inhibiting negative Clapeyron slope but also is a compositional boundary between fractionated (not "primitive"), sluggish lower mantle and fertile, mobile upper mantle. Slabs sink more steeply than they dip. Slabs older than about 60 Ma when their subduction began sink to, and lie down on and depress, the 650-km discontinuity, and are overpassed, whereas younger slabs become neutrally buoyant in mid-upper mantle, into which they are mixed as they too are overpassed. Broadside-sinking old slabs push all upper mantle, from base of oceanic lithosphere down to the 650, back under

  1. Optimization of geometrical characteristics of perforated plates

    International Nuclear Information System (INIS)

    Radisavljevic, Igor; Balos, Sebastian; Nikacevic, Milutin; Sidjanin, Leposava

    2013-01-01

    Highlights: ► Perforated plate are tested against 12.7 mm API projectile. ► Perforations similar to the projectile diameter offer more efficient core fracture. ► Larger perforations gave a more efficient core fragmentation. ► SEM microscopy analysis has shown a ductile fracture mode at impact point. - Abstract: In this paper, an attempt was made to design effective non-homogenous armor in form of perforated plate mounted at close distance from basic armor plate. Perforated plate with three perforation diameters: 9, 10 and 11 mm, two ligaments length: 3.5 and 4.5 mm ligaments, set at 0° and 28° angles, were combined to 13 mm basic plate and tested against 12.7 mm API ammunition. It has been shown that larger perforations gave a more efficient core fragmentation, while angled specimens were the only ones that offer full protection against five API shots when the perforated plate was placed at 100 mm from the basic plate. Perforations that are similar in size to the penetrating core diameter offer a more efficient core fracture, leading to a faster fragment separation. This may enable a smaller distance between the add-on perforated and basic plate to be used. Scanning electron microscopy analysis has shown a ductile fracture mode at impact point, with hardness values on plate basic level. On the other hand, a brittle fracture mode with a rise in local hardness measured near impact point is a result of intensive high speed plastic deformation produced by bending stresses. A drop in local hardness measured near impact point, may be the result of intensive cracking that occur due to repeated projectile impact

  2. Fabrication of conductive copper patterns using reactive inkjet printing followed by two-step electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jin-Ju; Lin, Guo-Qiang; Wang, Yan [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China); Sowade, Enrico; Baumann, Reinhard R. [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz, 09126 (Germany); Feng, Zhe-Sheng, E-mail: fzs@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 (China)

    2017-02-28

    Highlights: • Copper patterns were fabricated by reactive inkjet printing and two-step electroless plating. • Cu particles produced via reactive inkjet printing act as catalyst for copper electroless plating. • High conductivity can be obtained without many printing passes and high temperature sintering. • This approach can largely avoid nozzle-clogging problems. • This approach presents a potential way in the flexible printed electronics with simple process. - Abstract: A simple and low-cost process for fabricating conductive copper patterns on flexible polyimide substrates was demonstrated. Copper catalyst patterns were first produced on polyimide substrates using reactive inkjet printing of Cu (II)-bearing ink and reducing ink, and then the conductive copper patterns were generated after a two-step electroless plating procedure. The copper layers were characterized by optical microscope, SEM, XRD and EDS. Homogeneously distributed copper nanoclusters were found in the catalyst patterns. A thin copper layer with uniform particle size was formed after first-step electroless plating, and a thick copper layer of about 14.3 μm with closely packed structure and fine crystallinity was produced after second-step electroless plating. This resulting copper layer had good solderability, reliable adhesion strength and a low resistivity of 5.68 μΩ cm without any sintering process.

  3. Fabrication of conductive copper patterns using reactive inkjet printing followed by two-step electroless plating

    International Nuclear Information System (INIS)

    Chen, Jin-Ju; Lin, Guo-Qiang; Wang, Yan; Sowade, Enrico; Baumann, Reinhard R.; Feng, Zhe-Sheng

    2017-01-01

    Highlights: • Copper patterns were fabricated by reactive inkjet printing and two-step electroless plating. • Cu particles produced via reactive inkjet printing act as catalyst for copper electroless plating. • High conductivity can be obtained without many printing passes and high temperature sintering. • This approach can largely avoid nozzle-clogging problems. • This approach presents a potential way in the flexible printed electronics with simple process. - Abstract: A simple and low-cost process for fabricating conductive copper patterns on flexible polyimide substrates was demonstrated. Copper catalyst patterns were first produced on polyimide substrates using reactive inkjet printing of Cu (II)-bearing ink and reducing ink, and then the conductive copper patterns were generated after a two-step electroless plating procedure. The copper layers were characterized by optical microscope, SEM, XRD and EDS. Homogeneously distributed copper nanoclusters were found in the catalyst patterns. A thin copper layer with uniform particle size was formed after first-step electroless plating, and a thick copper layer of about 14.3 μm with closely packed structure and fine crystallinity was produced after second-step electroless plating. This resulting copper layer had good solderability, reliable adhesion strength and a low resistivity of 5.68 μΩ cm without any sintering process.

  4. Heat insulating plates

    Energy Technology Data Exchange (ETDEWEB)

    Allan, J.A.F.

    1976-10-28

    Micro-porous insulation plates are dealt with, for example, how they are used in the insulation of heat storage devices. Since one side of such plates is exposed to a temperature of over 700/sup 0/C, a shrinkage of the glass texture of the covering can occur, which can exceed the shrinkage of the inner micro-porous material, so that cracks and splits in the high temperature side of the covering can come about. The task of the invention is to design the plate in such a way as to prevent this from happening. For this purpose the plate is provided, according to invention specifications, with flutes, waves, ribs, waffle or grid patterns and the covering is set into the recesses originating from this.

  5. Create Your Plate

    Medline Plus

    Full Text Available ... Plate is a simple and effective way to manage your blood glucose levels and lose weight. With ... been easier. It can be a challenge to manage portion control wherever you are. Now, our best- ...

  6. Create Your Plate

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    Full Text Available ... Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate en -- A Future Without Diabetes - a- ...

  7. Create Your Plate

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    Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart- ...

  8. Create Your Plate

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    Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

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    Full Text Available ... Children and Type 2 Diabetes Know Your Rights Employment Discrimination Health Care Professionals Law Enforcement Driver's License ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

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    Full Text Available ... diabetes. Other Ways to Give Become a Member Vehicle Donation Planned Giving Options Memorial Giving Brochures & Envelopes ... to manage your blood glucose levels and lose weight. With this method, you fill your plate with ...

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    Full Text Available ... these seven steps to get started: Using your dinner plate, put a line down the middle of ... Fitness Food Recipes Planning Meals What Can I Eat Weight Loss Fitness In My Community Calendar of ...

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    Full Text Available ... 800-342-2383) Give by Mail Close ... your plate with more non-starchy veggies and smaller portions of starchy foods and protein—no special tools or counting required! You can ...

  20. Humvee Armor Plate Drilling

    National Research Council Canada - National Science Library

    2004-01-01

    When drilling holes in hard steel plate used in up-armor kits for Humvee light trucks, the Anniston Army Depot, Anniston, Alabama, requested the assistance of the National Center for Defense Manufacturing and Machining (NCDMM...

  1. Create Your Plate

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    Full Text Available ... Easy Advocacy Checklists for Association Events Messaging Tools Recruiting Advocates Local Market Planning Training Webinars News & Events ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  2. Create Your Plate

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    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... Complications Health Insurance For Parents & Kids Know Your Rights We Can Help Enroll in the Living WIth ...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... today and help fund grants supporting next generation scientists. Donate Today We Can Help - we-can-help. ...

  4. BAO Plate Archive Project

    Science.gov (United States)

    Mickaelian, A. M.; Gigoyan, K. S.; Gyulzadyan, M. V.; Paronyan, G. M.; Abrahamyan, H. V.; Andreasyan, H. R.; Azatyan, N. M.; Kostandyan, G. R.; Samsonyan, A. L.; Mikayelyan, G. A.; Farmanyan, S. V.; Harutyunyan, V. L.

    2017-12-01

    We present the Byurakan Astrophysical Observatory (BAO) Plate Archive Project that is aimed at digitization, extraction and analysis of archival data and building an electronic database and interactive sky map. BAO Plate Archive consists of 37,500 photographic plates and films, obtained with 2.6m telescope, 1m and 0.5m Schmidt telescopes and other smaller ones during 1947-1991. The famous Markarian Survey (or the First Byurakan Survey, FBS) 2000 plates were digitized in 2002-2005 and the Digitized FBS (DFBS, www.aras.am/Dfbs/dfbs.html) was created. New science projects have been conducted based on this low-dispersion spectroscopic material. Several other smaller digitization projects have been carried out as well, such as part of Second Byurakan Survey (SBS) plates, photographic chain plates in Coma, where the blazar ON 231 is located and 2.6m film spectra of FBS Blue Stellar Objects. However, most of the plates and films are not digitized. In 2015, we have started a project on the whole BAO Plate Archive digitization, creation of electronic database and its scientific usage. Armenian Virtual Observatory (ArVO, www.aras.am/Arvo/arvo.htm) database will accommodate all new data. The project runs in collaboration with the Armenian Institute of Informatics and Automation Problems (IIAP) and will continues during 4 years in 2015-2018. The final result will be an Electronic Database and online Interactive Sky map to be used for further research projects. ArVO will provide all standards and tools for efficient usage of the scientific output and its integration in international databases.

  5. Neutron imaging plates

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1995-01-01

    Imaging plates have been used in the field of medical diagnosis since long ago, but their usefulness was verified as the two-dimensional detector for analyzing the X-ray crystalline structure of high bio molecules like protein, and they have contributed to the remarkable progress in this field. The great contribution is due to the excellent features, such as the detection efficiency of about 100%, the positional resolution smaller than 0.2 mm, the dynamic range of five digits, and the area of several hundreds mm square. The neutron imaging plates have not yet obtained the sufficient results. It was planned to construct the neutron diffractometer for biological matters, and to put imaging plate neutron detectors (IP-ND) to practical use as the detector. The research on the development of IP-NDs was carried out, and the IPp-NDs having the performance comparable with that for X-ray were able to be produced. Imaging plates are the integral type two-dimensional radiation detector using photostimulated luminescence matters, and their principle is explained. As to neutron imaging plates, the converter, neutron detection efficiency and the flight of secondary particles in photo-stimulated luminescence matters are described. As for the present state of development of neutron imaging plates, the IP-NDs made for trial, the dynamic range, the positional resolution, the detection efficiency and the kinds of converters, and the application of IP-NDs are reported. (K.I.)

  6. Numerical prediction of mechanical properties of Pb-Sn solder alloys containing antimony, bismuth and or silver ternary trace elements

    Science.gov (United States)

    Gadag, Shiva P.; Patra, Susant

    2000-12-01

    Solder joint interconnects are mechanical means of structural support for bridging the various electronic components and providing electrical contacts and a thermal path for heat dissipation. The functionality of the electronic device often relies on the structural integrity of the solder. The dimensional stability of solder joints is numerically predicted based on their mechanical properties. Algorithms to model the kinetics of dissolution and subsequent growth of intermetallic from the complete knowledge of a single history of time-temperature-reflow profile, by considering equivalent isothermal time intervals, have been developed. The information for dissolution is derived during the heating cycle of reflow and for the growth process from cooling curve of reflow profile. A simple and quick analysis tool to derive tensile stress-strain maps as a function of the reflow temperature of solder and strain rate has been developed by numerical program. The tensile properties are used in modeling thermal strain, thermal fatigue and to predict the overall fatigue life of solder joints. The numerical analysis of the tensile properties as affected by their composition and rate of testing, has been compiled in this paper. A numerical model using constitutive equation has been developed to evaluate the interfacial fatigue crack growth rate. The model can assess the effect of cooling rate, which depends on the level of strain energy release rate. Increasing cooling rate from normalizing to water-quenching, enhanced the fatigue resistance to interfacial crack growth by up to 50% at low strain energy release rate. The increased cooling rates enhanced the fatigue crack growth resistance by surface roughening at the interface of solder joint. This paper highlights salient features of process modeling. Interfacial intermetallic microstructure is affected by cooling rate and thereby affects the mechanical properties.

  7. In-vitro investigations of skin closure using diode laser and protein solder containing gold nano shells

    International Nuclear Information System (INIS)

    Nourbakhsh, M. S.; Etrati Khosroshahi, M.

    2011-01-01

    Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nano shells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nano shells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nano shells were prepared. A full thickness incision of 2*20 mm 2 was made on the surface and after placing 50 μ1 of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nano shell concentrations. In addition, at constant laser irradiance (I), the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to σt = 1610 g/cm 2 at I ∼ 60 W cm-2, T ∼ 65 d egree C , Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nano shells can be used as an indocyanine green dye alterative for laser tissue soldering. Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

  8. Contact of ZnSb thermoelectric material to metallic electrodes using S-Bond 400 solder alloy

    DEFF Research Database (Denmark)

    Malik, Safdar Abbas; Le, Thanh Hung; Van Nong, Ngo

    2018-01-01

    and metallic electrodes. In this paper, we investigate the joining of ZnSb to Ni and Ag electrodes using a commercial solder alloy S-Bond 400 and hot-pressing technique. Ti and Cr layers are also introduced as a diffusion barrier and microstructure at the interfaces is observed by scanning electron microscopy....... We found that S-bond 400 solder reacts with Ag and Ni electrodes to form different alloys at the interfaces. Cr layer was found to be broken after joining, resulting in a thicker reaction/diffusion layer at the interface, while Ti layer was preserved....

  9. Damage Model for Reliability Assessment of Solder Joints in Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    environmental factors. Reliability assessment for such type of products conventionally is performed by classical reliability techniques based on test data. Usually conventional reliability approaches are time and resource consuming activities. Thus in this paper we choose a physics of failure approach to define...... damage model by Miner’s rule. Our attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Based on the proposed method it is described how to find the damage level for a given temperature loading profile. The proposed method is discussed...

  10. Decomposition studies of no-clean solder flux systems in connection with corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Verdingovas, Vadimas

    2013-01-01

    with specific soldering process and parameters, while most important factors are the flux chemistry and its decomposition characteristics. Active parts of the flux residue can cause increased water absorption due to their hygroscopic nature and in solution they will increase leakage current and corrosion...... the contaminated PCBA parts to varying humidity and measuring the resulting leakage current. Results revealed a significant influence of flux chemistry including the amount of WOAs, while aggressiveness of the residue seems to vary with content and type of WOAs, and their nature of decomposition....

  11. Improved Switching Characteristics of Fast Power MOSFETs Applying Solder Bump Technology

    Directory of Open Access Journals (Sweden)

    Sibylle Dieckerhoff

    2008-01-01

    Full Text Available The impact of a reduced package stray inductance on the switching performance of fast power MOSFETs is discussed applying advanced 3D packaging technologies. Starting from an overview over new packaging approaches, a solder bump technology using a flexible PI substrate is exemplarily chosen for the evaluation. Measurement techniques to determine the stray inductance are discussed and compared with a numerical solution based on the PEEC method. Experimental results show the improvement of the voltage utilization while there is only a slight impact on total switching losses.

  12. In situ TEM observation of microcrack nucleation and propagation in pure tin solder

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li, Mingyu; Wang Weiqiang

    2006-01-01

    Microcrack nucleation and propagation behavior in pure tin solder was investigated by using transmission electron microscopy (TEM) through in situ tensile test. Observation results showed that fracture process was completed in this visco-plastic material by connecting discontinuous cracks or voids. Depending on remarkable vacancy diffusion ability, microvoids were nucleated and developed in the dislocation free zone (DFZ) or super thinned area ahead of crack tip under local high stress concentration. The cracks were linked with each other by mutual dislocation emission which expedites the propagation of crack tips effectively

  13. Soldering Technology (6th) Proceedings of Annual Seminar, 17-18 February 1982.

    Science.gov (United States)

    1982-02-01

    aspect oF health and safety during this presentation. We are hoping that the work conducted by Van 2 Der Molen in the USA will clarify this issue. FLUX... Der Molen , PROC. OF 5th ANNUAL SEMINAR SOLDERING TECHNOLOGY, Naval Weapons Centre, China Lake, California, February 1981. 3. Burge, Perks, O’Brien...developed a new and innovative solution, which we believe to be a significant advance in the state of the art. In this new design (Fig.l) a FM DER

  14. History of internal fixation with plates (part 2): new developments after World War II; compressing plates and locked plates.

    Science.gov (United States)

    Hernigou, Philippe; Pariat, Jacques

    2017-07-01

    The first techniques of operative fracture with plates were developed in the 19th century. In fact, at the beginning these methods consisted of an open reduction of the fracture usually followed by a very unstable fixation. As a consequence, the fracture had to be opened with a real risk of (sometimes lethal) infection, and due to unstable fixation, protection with a cast was often necessary. During the period between World Wars I and II, plates for fracture fixation developed with great variety. It became increasingly recognised that, because a fracture of a long bone normally heals with minimal resorption at the bone ends, this may result in slight shortening and collapse, so a very rigid plate might prevent such collapse. However, as a consequence, delayed healing was observed unless the patient was lucky enough to have the plate break. One way of dealing with this was to use a slotted plate in which the screws could move axially, but the really important advance was recognition of the role of compression. After the first description of compression by Danis with a "coapteur", Bagby and Müller with the AO improved the technique of compression. The classic dynamic compression plates from the 1970s were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates resulted in delayed union and the osteoporosis, cancellous bone, comminution, and/or pathological bone resulted in some failures due to insufficient stability. Finally, new devices represented by locking plates increased the stability, contributing to the principles of a more biological osteosynthesis while giving enough stability to allow immediate full weight bearing in some patients.

  15. Lead Poisoning

    Science.gov (United States)

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  16. Design review report, 241-S-102 cover plate review; TOPICAL

    International Nuclear Information System (INIS)

    ADAMS, M.R.

    1998-01-01

    The design for the cover plate and lead plate for shielding on 241-S-102 was reviewed on 10/21/98. All Review Comment Record comments were resolved to the satisfaction of the reviewers. Additional comments were taken during the meeting and were also resolved. A design calculation for the Radiological Design Review Screening was presented as criteria for the use of 1 inch lead plate. The review concluded that the use of 2 inch steel plate and 1 inch lead plate provided the required safety function required by HNF-SD-WM-810-001, 5.3.2.20, Basis for Interim Operation. The design was approved with the incorporated comments as recorded on RCR's and meeting minutes

  17. Quantitative assessment of growth plate activity

    International Nuclear Information System (INIS)

    Harcke, H.T.; Macy, N.J.; Mandell, G.A.; MacEwen, G.D.

    1984-01-01

    In the immature skeleton the physis or growth plate is the area of bone least able to withstand external forces and is therefore prone to trauma. Such trauma often leads to premature closure of the plate and results in limb shortening and/or angular deformity (varus or valgus). Active localization of bone seeking tracers in the physis makes bone scintigraphy an excellent method for assessing growth plate physiology. To be most effective, however, physeal activity should be quantified so that serial evaluations are accurate and comparable. The authors have developed a quantitative method for assessing physeal activity and have applied it ot the hip and knee. Using computer acquired pinhole images of the abnormal and contralateral normal joints, ten regions of interest are placed at key locations around each joint and comparative ratios are generated to form a growth plate profile. The ratios compare segmental physeal activity to total growth plate activity on both ipsilateral and contralateral sides and to adjacent bone. In 25 patients, ages 2 to 15 years, with angular deformities of the legs secondary to trauma, Blount's disease, and Perthes disease, this technique is able to differentiate abnormal segmental physeal activity. This is important since plate closure does not usually occur uniformly across the physis. The technique may permit the use of scintigraphy in the prediction of early closure through the quantitative analysis of serial studies

  18. Interfacial reaction of Ni{sub 3}Sn{sub 4} intermetallic compound in Ni/SnAg solder/Ni system under thermomigration

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yi-Shan; Yang, Chia-Jung; Ouyang, Fan-Yi, E-mail: fyouyang@ess.nthu.edu.tw

    2016-07-25

    The growth of Ni{sub 3}Sn{sub 4} intermetallic compound (IMC) between liquid–solid interface in micro-scale Ni/SnAg/Ni system was investigated under a temperature gradient of 160 °C/cm at 260 °C on a hot plate. In contrast to a symmetrical growth of Ni{sub 3}Sn{sub 4} on both interfaces under isothermally annealed at 260 °C, the interfacial Ni{sub 3}Sn{sub 4} IMC exhibited asymmetric growth under a temperature gradient; the growth of Ni{sub 3}Sn{sub 4} at cold interface was faster than that at hot side because of temperature gradient induced mass migration of Ni atoms from the hot end toward the cold end. It was found that two-stage growth behavior of Ni{sub 3}Sn{sub 4} IMC under a temperature gradient. A growth model was established and growth kinetic analysis suggested that the chemical potential gradient controlled the growth of Ni{sub 3}Sn{sub 4} at stage I (0–120 min) whereas the dynamic equilibrium between chemical potential gradient and temperature gradient forces was attained at the hot end at stage II (120–210 min). When dynamic equilibrium was achieved at 260 °C, the critical length-temperature gradient product at the hot end was experimentally estimated to be 489.18 μm × °C/cm and the moving velocity of Ni{sub 3}Sn{sub 4} interface due to Ni consumption was calculated to be 0.134 μm/h. The molar heat of transport (Q*) of Ni atoms in molten SnAg solder was calculated to be +0.76 kJ/mol. - Highlights: • Interfacial reaction in Ni/SnAg solder/Ni system under thermal gradient. • Growth rate of Ni{sub 3}Sn{sub 4} at cold end is faster than that at hot end. • Critical length-temperature gradient product at hot end is 489.2 μm°C/cm at 260 °C. • Velocity of Ni{sub 3}Sn{sub 4} moving interface is 0.134 μm/h during dynamic equilibrium. • Molar heat of transport (Q*) of Ni in molten SnAg was +0.76 kJ/mol.

  19. Effect of thiram on chicken growth plate cartilage

    Science.gov (United States)

    Thiram is a general use dithiocarbamate pesticide. It causes tibial dyschondroplasia, a growth plate cartilage defect in poultry characterized by growth plate broadening due to the accumulation of nonviable chondrocytes which lead to lameness. Since proteins play significant roles in all aspects cel...

  20. Cadmium plating replacements

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  1. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  2. Miniaturization of Micro-Solder Bumps and Effect of IMC on Stress Distribution

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2016-07-01

    As the joints become smaller in more advanced packages and devices, intermetallic (IMCs) volume ratio increases, which significantly impacts the overall mechanical behavior of joints. The existence of only a few grains of Sn (Tin) and IMC materials results in anisotropic elastic and plastic behavior which is not detectable using conventional finite element (FE) simulation with average properties for polycrystalline material. In this study, crystal plasticity finite element (CPFE) simulation is used to model the whole joint including copper, Sn solder and Cu6Sn5 IMC material. Experimental lap-shear test results for solder joints from the literature were used to validate the models. A comparative analysis between traditional FE, CPFE and experiments was conducted. The CPFE model was able to correlate the experiments more closely compared to traditional FE analysis because of its ability to capture micro-mechanical anisotropic behavior. Further analysis was conducted to evaluate the effect of IMC thickness on stress distribution in micro-bumps using a systematic numerical experiment with IMC thickness ranging from 0% to 80%. The analysis was conducted on micro-bumps with single crystal Sn and bicrystal Sn. The overall stress distribution and shear deformation changes as the IMC thickness increases. The model with higher IMC thickness shows a stiffer shear response, and provides a higher shear yield strength.

  3. Soldered Power Arm: An Easy and Effective Method for Intrusion and Retraction of Anterior Teeth

    Directory of Open Access Journals (Sweden)

    Ketan K Vakil

    2014-01-01

    Full Text Available The orthodontic correction of deep overbite can be achieved with several mechanisms that will result in true intrusion of anterior teeth, extrusion of posterior teeth, or a combination of both. For the orthodontic correction of bimaxillary dentoalveolar protrusion with deep bite, there are several treatment modalities like segmented arch approach, retraction and intrusion utility arches, temporary anchorage devices. Though not a novel therapeutic concept, the use of miniscrew implants to obtain absolute anchorage has recently become very popular in clinical orthodontic approaches. To allow the use of sliding mechanics for bodily retraction with intrusion of anterior teeth, we devised a soldered power arm (SPA on standard molar tube. It is simple, stable, precise and effective in cases where anterior teeth need to be simultaneously retracted and intruded. A power arm can be readily fabricated from 20 gauge stainless steel wire and soldered on the molar buccal tube so as to avoid any distortion or loosening of power arm from molar tube during the course of the treatment. The SPA works efficiently with the molar being stabilized in all three planes of space. The resultant force vector is directed more apically toward the center of resistance of the anchor unit, which resulted in the treatment outcome of retraction and intrusion of the anterior teeth and correction of the deep bite.

  4. Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

    2016-08-15

    The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

  5. Interactions of Cu-substrates with titanium-alloyed Sn-Zn solders

    Directory of Open Access Journals (Sweden)

    Soares D.

    2006-01-01

    Full Text Available The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the second series,. The contact times were up to 3600 s. The contact zones have been characterized by optical and scanning electron microscope. Two layers have been found along the interfaces solid/liquid. The first and the second layers are identical, respectively, with γ and ε phases of the Cu-Zn system. No changes of the chemical compositions were detected for the tested temperatures and reaction times. Continuous parabolic growth of the total diffusion zone thickness with the time of diffusion is observed. The growth is due mainly to one the formed layers (γ while the thickness of the ε-phase layer, stays almost constant for all tested diffusion times and temperatures.

  6. Economical surface treatment of die casting dies to prevent soldering in high pressure casting

    International Nuclear Information System (INIS)

    Fraser, D.T.; Jahedi, M.Z.

    2001-01-01

    This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure

  7. The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM

    Science.gov (United States)

    Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

    2008-06-01

    This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

  8. Mechanism of Solder Joint Cracks in Anisotropic Conductive Films Bonding and Solutions: Delaying Hot-Bar Lift-Up Time and Adding Silica Fillers

    Directory of Open Access Journals (Sweden)

    Shuye Zhang

    2018-01-01

    Full Text Available Micron sizes solder metallurgical joints have been applied in a thin film application of anisotropic conductive film and benefited three general advantages, such as lower joint resistance, higher power handling capability, and reliability, when compared with pressure based contact of metal conductor balls. Recently, flex-on-board interconnection has become more and more popular for mobile electronic applications. However, crack formation of the solder joint crack was occurred at low temperature curable acrylic polymer resins after bonding processes. In this study, the mechanism of SnBi58 solder joint crack at low temperature curable acrylic adhesive was investigated. In addition, SnBi58 solder joint cracks can be significantly removed by increasing the storage modulus of adhesives instead of coefficient of thermal expansion. The first approach of reducing the amount of polymer rebound can be achieved by using an ultrasonic bonding method to maintain a bonding pressure on the SnBi58 solder joints cooling to room temperature. The second approach is to increase storage modulus of adhesives by adding silica filler into acrylic polymer resins to prevent the solder joint from cracking. Finally, excellent acrylic based SnBi58 solder joints reliability were obtained after 1000 cycles thermal cycling test.

  9. Mechanical obstacles to the movement of continent-bearing plates

    Science.gov (United States)

    Lowman, P. D., Jr.

    1985-01-01

    Selected geophysical problems associated with the concept of continental drift as an incidental corollary of plate movement are discussed. The problems include the absence of a suitable plate-driving mechanism for plates with continental leading edges, the absence of the low-velocity zone under shields, and continental roots of 400 to 700 km depths. It is shown that if continental drift occurs, it must use mechanisms not now understood, or that it may not occur at all, plate movement being confined to ocean basins.

  10. Plating on Zircaloy-2

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.; Jones, A.

    1979-03-01

    Zircaloy-2 is a difficult alloy to coat with an adherent electroplate because it easily forms a tenacious oxide film in air and aqueous solutions. Procedures reported in the literature and those developed at SLL for surmounting this problem were investigated. The best results were obtained when specimens were first etched in either an ammonium bifluoride/sulfuric acid or an ammonium bifluoride solution, plated, and then heated at 700 0 C for 1 hour in a constrained condition. Machining threads in the Zircaloy-2 for the purpose of providing sites for mechanical interlocking of the plating also proved satisfactory

  11. NICKEL PLATING PROCESS

    Science.gov (United States)

    Hoover, T.B.; Zava, T.E.

    1959-05-12

    A simplified process is presented for plating nickel by the vapor decomposition of nickel carbonyl. In a preferred form of the invention a solid surface is nickel plated by subjecting the surface to contact with a mixture containing by volume approximately 20% nickel carbonyl vapor, 2% hydrogen sulfide and .l% water vapor or 1% oxygen and the remainder carbon dioxide at room temperature until the desired thickness of nickel is obtained. The advantage of this composition over others is that the normally explosive nickel carbonyl is greatly stabilized.

  12. Instrumentation of fuel elements and fuel plates

    International Nuclear Information System (INIS)

    Durand, J.P.; Fanjas, Y.

    1994-01-01

    When controlling the behaviour of a reactor or developing a new fuel concept, it is of utmost interest to have the possibility to confirm the thermohydraulic calculations by actual measurements in the fuel elements or in the fuel plates. For years, CERCA has developed the technology and supplied its customers with fuel elements equipped with pressure or temperature measuring devices according to the requirements. Recent customer projects have lead to the development of a new method to introduce thermocouples directly into the fuel plate meat instead of the cladding. The purpose of this paper is to review the various instrumentation possibilities available at CERCA. (author)

  13. Modelling of CMUTs with Anisotropic Plates

    DEFF Research Database (Denmark)

    la Cour, Mette Funding; Christiansen, Thomas Lehrmann; Jensen, Jørgen Arendt

    2012-01-01

    Traditionally, CMUTs are modelled using the isotropic plate equation and this leads to deviations between analytical calculations and FEM simulations. In this paper, the deflection profile and material parameters are calculated using the anisotropic plate equation. It is shown that the anisotropic...... calculations match perfectly with FEM while an isotropic approach causes up to 10% deviations in deflection profile. Furthermore, we show how commonly used analytic modelling methods such as static calculations of the pull-in voltage and dynamic modelling through an equivalent circuit representation can...

  14. Hydrodynamics of a flexible plate between pitching rigid plates

    Science.gov (United States)

    Kim, Junyoung; Kim, Daegyoum

    2017-11-01

    The dynamics of a flexible plate have been studied as a model problem in swimming and flying of animals and fluid-structure interaction of plants and flags. Motivated by fish schooling and an array of sea grasses, we investigate the dynamics of a flexible plate closely placed between two pitching rigid plates. In most studies on passive deformation of the flexible plate, the plate is immersed in a uniform flow or a wavy flow. However, in this study, the flexible plate experiences periodic deformation by the oscillatory flow generated by the prescribed pitching motion of the rigid plates. In our model, the pitching axes of the rigid plates and the clamping position of the flexible plate are aligned on the same line. The flexible plate shows various responses depending on length and pitching frequency of rigid plates, thickness of a flexible plate, and free-stream velocity. To find the effect of each variable on the response of the flexible plate, amplitude of a trailing edge and modal contribution of a flapping motion are compared, and flow structure around the flexible plate is examined.

  15. Interfacial Microstructure and Shear Strength of Brazed Cu-Cr-Zr Alloy Cylinder and Cylindrical Hole by Au Based Solder

    Directory of Open Access Journals (Sweden)

    Zaihua Li

    2017-07-01

    Full Text Available Au-Ge-Ni solder was chosen for brazing of the Cu-Cr-Zr alloy cylinder and a part with a cylindrical hole (sleeve below 550 °C. The Au based solder was first sintered on the surface of the cylinder and then brazed to the inner surface of the sleeve. The effects of the heating process, the temperature and the holding time at the temperature on the microstructure of the sintered layer on the surface of the cylinder, the brazed interfacial microstructure, and the brazed shear strength between the cylinder and the sleeve were investigated by scanning electron microscope, energy dispersive X-ray spectroscopy analysis, and tensile shear tests. By approach of side solder melt feeding and brazing under proper parameters, the voids and micro cracks due to a lack of enough solder melt feeding are greatly lessened and the brazed shear strength of 100 MPa is ensured even with large clearances around 0.01 mm.

  16. Three-dimensional (3D) visualization of reflow porosity and modeling of deformation in Pb-free solder joints

    International Nuclear Information System (INIS)

    Dudek, M.A.; Hunter, L.; Kranz, S.; Williams, J.J.; Lau, S.H.; Chawla, N.

    2010-01-01

    The volume, size, and dispersion of porosity in solder joints are known to affect mechanical performance and reliability. Most of the techniques used to characterize the three-dimensional (3D) nature of these defects are destructive. With the enhancements in high resolution computed tomography (CT), the detection limits of intrinsic microstructures have been significantly improved. Furthermore, the 3D microstructure of the material can be used in finite element models to understand their effect on microscopic deformation. In this paper we describe a technique utilizing high resolution (< 1 μm) X-ray tomography for the three-dimensional (3D) visualization of pores in Sn-3.9Ag-0.7Cu/Cu joints. The characteristics of reflow porosity, including volume fraction and distribution, were investigated for two reflow profiles. The size and distribution of porosity size were visualized in 3D for four different solder joints. In addition, the 3D virtual microstructure was incorporated into a finite element model to quantify the effect of voids on the lap shear behavior of a solder joint. The presence, size, and location of voids significantly increased the severity of strain localization at the solder/copper interface.

  17. Improvements of Nickel Deposit Characteristics by Pulse Plating

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Leisner, Peter; Møller, Per

    1993-01-01

    Investigation of the properties of electroplated nickel, using both pulse plating and conventional di-rect current (DC), has lead to several interesting improvements of deposit characteristics. Investigated properties include; internal stress, tensile strength, yield stress, elongation, hardness...

  18. Analysis of Terminal Metallic Armor Plate Free-Surface Bulging

    National Research Council Canada - National Science Library

    Rapacki, Jr, E. J

    2008-01-01

    An analysis of the bulge formed on the free-surface of the terminal metallic plate of an armor array is shown to lead to reasonable estimates of the armor array's remaining penetration/perforation resistance...

  19. Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hattel, Jesper Henri; Hald, John

    2010-01-01

    of the Au–Sn binary system were explored in this work. Furthermore, the effects of thermal aging on the microstructure and microhardness of these promising Au–Sn based ternary alloys were investigated. For this purpose, the candidate alloys were aged at a lower temperature, 150°C for up to 1week...

  20. Phase diagram prediction and particle characterisation of Sn-Ag nano alloy for low melting point lead-free solders

    Czech Academy of Sciences Publication Activity Database

    Sopoušek, J.; Vřešťál, J.; Zemanová, Adéla; Buršík, Jiří

    2012-01-01

    Roč. 48, č. 3 (2012), s. 419-425 ISSN 1450-5339 R&D Projects: GA ČR(CZ) GA106/09/0700 Institutional support: RVO:68081723 Keywords : tin * silver * nanoparticle Subject RIV: BJ - Thermodynamics Impact factor: 1.435, year: 2012

  1. Create Your Plate

    Medline Plus

    Full Text Available ... meal-planning, . In this section Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate en -- A Future Without Diabetes - a-future-without-diabetes-2.html A Future ...

  2. Create Your Plate

    Medline Plus

    Full Text Available ... tool is not to scale because of the differences in types of vegetables. When creating your plate ... function (data) { $('#survey-errors').remove(); $('.survey-form .form-group .survey-alert-wrap').remove(); if (data.submitSurveyResponse.success == ' ...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate en -- A Future Without Diabetes - a-future-without-diabetes-2.html A Future Without Diabetes Donate towards research today and your gift will be matched. Donate ...

  4. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals > Create Your Plate Share: Print Page Text Size: A A A Listen En Español Create ... Type 2 Education Series Hear audio clips and full recordings of past Q&A events at your ...

  5. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  6. Create Your Plate

    Medline Plus

    Full Text Available ... tax-deductible gift today can fund critical diabetes research and support vital diabetes education services that improve the ... effective way to manage your blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  7. Microchannel plate photodetectors

    International Nuclear Information System (INIS)

    Majka, R.

    1977-01-01

    A review is given the status of development work on photodetectors using microchannel plates (MCP) as the electron gain element. Projections are made and opinions are presented on what might be available in the next few years. Several uses for these devices at ISABELLE are mentioned

  8. Parallel plate detectors

    International Nuclear Information System (INIS)

    Gardes, D.; Volkov, P.

    1981-01-01

    A 5x3cm 2 (timing only) and a 15x5cm 2 (timing and position) parallel plate avalanche counters (PPAC) are considered. The theory of operation and timing resolution is given. The measurement set-up and the curves of experimental results illustrate the possibilities of the two counters [fr

  9. Flat plate collector. Solarflachkollektor

    Energy Technology Data Exchange (ETDEWEB)

    Raab, N

    1979-03-29

    The invention refers to a flat solar collector with an absorber plate, which is arranged on a support and is covered by a transparent window, between which and the plate there is an air space. The previously known structures of this type had the disadvantage that the thermal expansion of the enclosed air caused considerable difficulties. The purpose of the invention is therefore to create a collector, which can be used on the modular system, retains its properties and is safe in spite of the great temperature variations. According to the invention this problem is solved by providing a compensating space in the collector, which is separated by a diaphragm from the airspace between the plate and the covering window. The airspace therefore remains sealed against the atmosphere, so that no dirt, corrosion of the inside and no condensation can reduce the efficiency of the collector. A rise in pressure due to an increase in temperature is immediately reduced by expansion of the diaphragm, which enters the compensation space. In order to increase the pressure in the airspace above the plate for increases in temperature, the compensation space is connected to the atmosphere. The diaphragm can be mirrored on the side towards the absorber, which makes the diaphragm into an insulating element, as it reflects radiated heat from the absorber.

  10. Lead poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Beijers, J A

    1952-01-01

    Three cases of acute lead poisoning of cattle herds via ingestion are reported, and reference is made to several other incidents of lead in both humans and animals. The quantity of lead which was found in the livers of the dead cows varied from 6.5 to 19 mg/kg, while 1160 mg/kg of lead in the liver was found for a young cow which was poisoned experimentally with 5 gms of lead acetate per day; hence, there appears to be great variability in the amounts deposited that can lead to intoxication and death. No evidence was found for a lead seam around the teeth, prophyrinuria, or basophil granules in the erythrocytes during acute or chronic lead poisoning of cattle or horses examined. Reference is made to attempts of finding the boundary line between increased lead absorption and lead intoxication in humans, and an examination of 60 laborers in an offset-printing office containing a great deal of inhalable lead (0.16 to 1.9 mg/cu m air) is reviewed. Physical deviation, basophylic granulation of erythrocytes, increased lead content of the urine, and porphyrinuria only indicate an increased absorption of lead; the use of the term intoxication is justified if, in addition, there are complaints of lack of appetite, constipation, fatigue, abdominal pain, and emaciation.

  11. Fiscal 1998 achievement report on regional consortium research and development project. Venture business raising type regional consortium - Small business creation base type (Preparation of monodispersed spherical particles for solder materials for application to high density semiconductor packaging - 2nd year); 1998 nendo komitsudo handotai jisso no tame no tanbunsan kyukei handa ryushi no sakusei ni kansuru kenkyu seika hokokusho (dai 2 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Fine solder grains have been developed, spherical in shape, uniform in diameter, high in dimensional precision, and high in surface cleanliness, which are necessary for the establishment of next-generation technologies of flip chip bonding and ball grid array which are indispensable for high-density high-reliability packaging of electronic devices such as LSI (large scale integration). Results attained in fiscal 1998 are described. A pulse pressure aided orifice injection method was used. Monodispersed grains are prepared for the Pb-63Sn solder and Sn-3.5Ag lead-free solder. In the case of a 200{mu}m-large orifice, the grain diameter was controlled to fall in the range of 190-210{mu}m and the accuracy was not lower than {+-}6{mu}m. The main goal of this project has been accomplished now that these figures were attained without a sorting process and satisfy the most rigorous conditions currently proposed by the industrial circle involved. The flow of hot liquid out of the orifice and the splitting process of grains were clarified by thermal hydraulic analysis. It was found that grains split and fly not because of instability due to Rayleigh surface waves but because of their liberation from surface tension when equipped with critical kinetic energy. (NEDO)

  12. Lead Toxicity

    Science.gov (United States)

    ... o Do not use glazed ceramics, home remedies, cosmetics, or leaded-crystal glassware unless you know that they are lead safe. o If you live near an industry, mine, or waste site that may have contaminated ...

  13. Relational Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  14. Lead Test

    Science.gov (United States)

    ... to do renovation and repair projects using lead-safe work practices to avoid creating more lead dust or ... in a dangerous area? Yes. If you are working in a potentially harmful environment with exposure to lead dust or fumes: Wash ...

  15. Structure of colloidal sphere-plate mixtures

    International Nuclear Information System (INIS)

    Doshi, N; Cinacchi, G; Van Duijneveldt, J S; Cosgrove, T; Prescott, S W; Grillo, I; Phipps, J; Gittins, D I

    2011-01-01

    In addition to containing spherical pigment particles, coatings usually contain plate-like clay particles. It is thought that these improve the opacity of the paint film by providing an efficient spacing of the pigment particles. This observation is counterintuitive, as suspensions of particles of different shapes and sizes tend to phase separate on increase of concentration. In order to clarify this matter a model colloidal system is studied here, with a sphere-plate diameter ratio similar to that found in paints. For dilute suspensions, small angle neutron scattering revealed that the addition of plates leads to enhanced density fluctuations of the spheres, in agreement with new theoretical predictions. On increasing the total colloid concentration the plates and spheres phase separate due to the disparity in their shape. This is in agreement with previous theoretical and experimental work on colloidal sphere-plate mixtures, where one particle acts as a depleting agent. The fact that no large scale phase separation is observed in coatings is ascribed to dynamic arrest in intimately mixed, or possibly micro-phase separated structures, at elevated concentration.

  16. Structure of colloidal sphere-plate mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, N; Cinacchi, G; Van Duijneveldt, J S; Cosgrove, T; Prescott, S W [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Grillo, I [Institut Laue-Langevin, 6 rue Jules Horowitz BP 156, 38042 Grenoble Cedex 9 (France); Phipps, J [Imerys Minerals Ltd, Par Moor Centre, Par Moor Road, Par, Cornwall PL24 2SQ (United Kingdom); Gittins, D I, E-mail: Giorgio.Cinacchi@bristol.ac.uk, E-mail: J.S.van-Duijneveldt@bristol.ac.uk [Imerys Performance and Filtration Minerals Ltd, 130 Castilian Drive, Goleta, CA 93117 (United States)

    2011-05-18

    In addition to containing spherical pigment particles, coatings usually contain plate-like clay particles. It is thought that these improve the opacity of the paint film by providing an efficient spacing of the pigment particles. This observation is counterintuitive, as suspensions of particles of different shapes and sizes tend to phase separate on increase of concentration. In order to clarify this matter a model colloidal system is studied here, with a sphere-plate diameter ratio similar to that found in paints. For dilute suspensions, small angle neutron scattering revealed that the addition of plates leads to enhanced density fluctuations of the spheres, in agreement with new theoretical predictions. On increasing the total colloid concentration the plates and spheres phase separate due to the disparity in their shape. This is in agreement with previous theoretical and experimental work on colloidal sphere-plate mixtures, where one particle acts as a depleting agent. The fact that no large scale phase separation is observed in coatings is ascribed to dynamic arrest in intimately mixed, or possibly micro-phase separated structures, at elevated concentration.

  17. 75 FR 81309 - Stainless Steel Plate from Belgium, Italy, Korea, South Africa, and Taiwan

    Science.gov (United States)

    2010-12-27

    ... (Second Review)] Stainless Steel Plate from Belgium, Italy, Korea, South Africa, and Taiwan AGENCY: United... on stainless steel plate from Belgium, Italy, Korea, South Africa, and Taiwan. SUMMARY: The... on stainless steel plate from Belgium, Italy, Korea, South Africa, and Taiwan would be likely to lead...

  18. Plate Full of Color

    Centers for Disease Control (CDC) Podcasts

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Plate Full of Color teaches the value of eating a variety of colorful and healthy foods.

  19. Study on Mitigation Method of Solder Corrosion for Crystalline Silicon Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Ju-Hee Kim

    2014-01-01

    Full Text Available The corrosion of 62Sn36Pb2Ag solder connections poses serious difficulties for outdoor-exposed photovoltaic (PV modules, as connection degradation contributes to the increase in series resistance (RS of PV modules. In this study, we investigated a corrosion mitigation method based on the corrosion mechanism. The effect of added sacrificial metal on the reliability of PV modules was evaluated using the oxidation-reduction (redox reaction under damp heat (DH conditions. Experimental results after exposure to DH show that the main reason for the decrease in power was a drop in the module’s fill factor. This drop was attributed to the increase of RS. The drop in output power of the PV module without added sacrificial metal is greater than that of the sample with sacrificial metal. Electroluminescence and current-voltage mapping analysis also show that the PV module with sacrificial metal experienced less degradation than the sample without sacrificial metal.

  20. Determination of Te in soldering tin using continuous flowing electrochemical hydride generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Jiang Xianjuan; Gan Wuer; Han Suping; He Youzhao

    2008-01-01

    An electrochemical hydride generation system was developed for the detection of Te by coupling an electrochemical hydride generator with atomic fluorescence spectrometry. Since TeH 2 is unstable and easily decomposes in solution, a reticular W filament cathode was used in the present system. The TeH 2 generated on the cathode surface was effectively driven out by sweeping gas from the cathode chamber. In addition, a low temperature electrochemical cell (10 deg. C) was applied to reduce the decomposition of TeH 2 in solution. The limit of detection (LOD) was 2.2 ng ml -1 and the relative standard deviation (RSD) was 3.9% for nine consecutive measurements of standard solution. This method was successfully employed for determination of Te in soldering tin material