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Sample records for technology smt soldering

  1. 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...

  2. 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.

  3. 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

  4. 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

  5. The Submillimeter Telescope (SMT) project

    International Nuclear Information System (INIS)

    Martin, R.N.; Baars, J.W.M.

    1990-01-01

    To exploit the potential of submillimeter astronomy, the Submillimeter Telescope (SMT) will be located at an altitude of 3178 meters on Emerald Peak 75 miles northeast of Tucson in Southern Arizona. The instrument is an altazimuth mounted f/13.8 Cassegrain homology telescope with two Nasmyth and bent Cassegrain foci. It will have diffraction limited performance at a wavelength of 300 microns and an operating overall figure accuracy of 15 microns rms. An important feature of the SMT is the construction of the primary and secondary reflectors out of aluminum-core CFRP face sheet sandwich panels, and the reflector backup structure and secondary support out of CFRP structural elements. This modern technology provides both a means for reaching the required precision of the SMT for both night and day operation (basically because of the low coefficient of thermal expansion and high strength-to-weight ratio of CFRP) and a potential route for the realization of lightweight telescopes of even greater accuracy in the future. The SMT will be the highest accuracy radio telescope ever built (at least a factor of 2 more accurate than existing telescopes). In addition, the SMT will be the first 10 m-class submillimeter telescope with a surface designed for efficient measurements at the important 350 microns wavelength atmospheric window. 9 refs

  6. NDE Conference on Civil Engineering : a joint conference of the 7th Structural Materials Technology Conference (SMT) and the 6th International Symposium on Nondestructive Testing in Civil Engineering (NDT-CE)

    Science.gov (United States)

    2007-01-01

    The 2006 NDE conference on Civil Engineering was held in St. Louis, MO on August 14 18, 2006. The conference combined the 7th Structural Materials Technology Conference (SMT) along with the 6th International Symposium on Nondestructive Testing in...

  7. 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...

  8. Quality investigation of surface mount technology using phase-shifting digital holography

    Science.gov (United States)

    Boonsri, Chantira; Buranasiri, Prathan

    2016-09-01

    Applying of a phase-shifting digital holography combined with compressive sensing to inspect the soldering quality of surface mount technology (SMT) which is a method for producing electronic circuits. In SMT, the components are mounted and connected with each other directly onto the surface of printed circuit boards (PCBs). By reconstructing the multidimensional images from a few samples of SMT, the results are solved by an optimization problem. In this paper, two problems have been concerned. The first one is to examine the devices and the soldering quality of connections between them, which are in micro-scaled. The second is to observe the effect of heat treatment of soldering material and devices on the surface mount board.

  9. Soldering sheets using soft solders

    Directory of Open Access Journals (Sweden)

    Milan Brožek

    2013-01-01

    Full Text Available The paper contains strength tests results of joints soldered using lead and leadless soft solders. For tests lead solders types Pb60Sn40 and Sn60Pb40 and leadless soft solders types Sn95.5Ag3.8Cu0.7 and Sn96Ag4 were used. As basic materials steel sheet, zinc-coated steel sheet, copper sheet and brass sheet 100 x 20 x 1 mm was the test samples size. Always two sheets were cleaned and jointed together. For heating the propane-butane + air flame was used. Then the tested assemblies were loaded using the universal tensile-strength testing machine till to failure. At the tests the force needed for assemblies failure and failure type (in soldered joint, in basic material were recorded. From measured data the solder strength was calculated. From the experiment results it follows that from the point of view of the soldered joints strength as well of the solder strength relatively small differences were found. At the same time it is evident that the joint strength and solder strength depend on soldered material type and on soldered joint lapping length. On the basis of carried out experiments it can be stated that the substitution of lead solders by leadless solders is possible without risk of soldered joints strength decrease.

  10. Soldering with ductile active solders

    Czech Academy of Sciences Publication Activity Database

    Dupák, Jan; Ustohal, V.

    2001-01-01

    Roč. 16, č. 6 (2001), s. 855 - 861 ISSN 1042-6914 Institutional research plan: CEZ:AV0Z2065902 Keywords : active solders * ductile solders * cryogenics devices Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.288, year: 2001

  11. 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%.

  12. vZ - An Optimizing SMT Solver

    DEFF Research Database (Denmark)

    Bjørner, Nikolaj; Dung, Phan Anh; Fleckenstein, Lars

    2015-01-01

    Z provides a portfolio of approaches for solving linear optimization problems over SMT formulas, MaxSMT, and their combinations. Objective functions are combined as either Pareto fronts, lexicographically, or each objective is optimized independently. We describe usage scenarios of vZ, outline the tool......vZ is a part of the SMT solver Z3. It allows users to pose and solve optimization problems modulo theories. Many SMT applications use models to provide satisfying assignments, and a growing number of these build on top of Z3 to get optimal assignments with respect to objective functions. v...

  13. Rewriting Modulo SMT and Open System Analysis

    Science.gov (United States)

    Rocha, Camilo; Meseguer, Jose; Munoz, Cesar

    2014-01-01

    This paper proposes rewriting modulo SMT, a new technique that combines the power of SMT solving, rewriting modulo theories, and model checking. Rewriting modulo SMT is ideally suited to model and analyze infinite-state open systems, i.e., systems that interact with a non-deterministic environment. Such systems exhibit both internal non-determinism, which is proper to the system, and external non-determinism, which is due to the environment. In a reflective formalism, such as rewriting logic, rewriting modulo SMT can be reduced to standard rewriting. Hence, rewriting modulo SMT naturally extends rewriting-based reachability analysis techniques, which are available for closed systems, to open systems. The proposed technique is illustrated with the formal analysis of: (i) a real-time system that is beyond the scope of timed-automata methods and (ii) automatic detection of reachability violations in a synchronous language developed to support autonomous spacecraft operations.

  14. Soldering on

    Czech Academy of Sciences Publication Activity Database

    Watson, A.; Kroupa, Aleš; Ipser, H.; Dinsdale, A.; Vřešťál, J.

    2007-01-01

    Roč. 15, č. 7 (2007), s. 32-33 ISSN 0967-8638 Institutional research plan: CEZ:AV0Z20410507 Keywords : lead -ree solders * high temperatures Subject RIV: BJ - Thermodynamics Impact factor: 0.153, year: 2007

  15. 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

  16. Shimadzu superconductive MRI system, SMT-100

    International Nuclear Information System (INIS)

    Yamauchi, Mikio; Shimizu, Koji; Itoh, Masamichi; Fujio, Yasuo; Hashimoto, Yasushi

    1989-01-01

    The magnetic resonance imaging (MRI) system SMT-100 operating at 1.0 T (Tesla) developed lately is reported on this paper. SMT-100 is graded as higher class and more effective system in MR-imaging systems. Purpose of development are (1) supply of high quality imaging, (2) high patient throughput, and (3) low operating cost. Following developments are carried out in this system: (1) development of 1.0 T superconducting magnet without liquid nitrogen vessel, attached self-magnetic shield, (2) development of digital controller system for being able to correspond to future pulse sequences, (3) development of flexible coil and establishment of displacement scanning method by fitting the coil on examination position, (4) separate console system (viewing console and scanning console) for high patient throughput. The outline of SMT-100 and clinical data by the system are reported here. (author)

  17. 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…

  18. Shimadzu magnetic resonance imaging system, SMT-50

    International Nuclear Information System (INIS)

    Oikawa, Shiro; Nishida, Takayuki; Fujio, Yasuo

    1986-01-01

    The magnetic resonance imaging (MRI) system, as a new modality of medical imaging, has already been put to practical applications on many clinical sites, through which a lot of clinical data has been accumulated. It can offer a powerful new probe of internal anatomy of the human body and its functions. Now that the MRI has established its effectiveness in diagnosis, a really practical MRI system which features high efficiency and economical design with high patient throughput is strongly called for. Introduced in this article is a superconductive magnet MRI system, SMT-50, operating at 5000 Gauss. It has realized an excellent diagnostic capability with such functions as multi-slice multi-echo imaging, high sensitive, surface coil technique and so on. High resolution image display (1024 x 1024 pixcel) unit and separate console system (viewing console and scanning console) will assist high patient throughput. The outline of the SMT-50 and its clinical data are reported here. (author)

  19. Solder flow over fine line PWB surface finishes

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Hernandez, C.L.

    1998-08-01

    The rapid advancement of interconnect technology has stimulated the development of alternative printed wiring board (PWB) surface finishes to enhance the solderability of standard copper and solder-coated surfaces. These new finishes are based on either metallic or organic chemistries. As part of an ongoing solderability study, Sandia National Laboratories has investigated the solder flow behavior of two azole-based organic solderability preservations, immersion Au, immersion Ag, electroless Pd, and electroless Pd/Ni on fine line copper features. The coated substrates were solder tested in the as-fabricated and environmentally-stressed conditions. Samples were processed through an inerted reflow machine. The azole-based coatings generally provided the most effective protection after aging. Thin Pd over Cu yielded the best wetting results of the metallic coatings, with complete dissolution of the Pd overcoat and wetting of the underlying Cu by the flowing solder. Limited wetting was measured on the thicker Pd and Pd over Ni finishes, which were not completely dissolved by the molten solder. The immersion Au and Ag finishes yielded the lowest wetted lengths, respectively. These general differences in solderability were directly attributed to the type of surface finish which the solder came in contact with. The effects of circuit geometry, surface finish, stressing, and solder processing conditions are discussed.

  20. 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.

  1. Solder joint reliability in solid-state lighting applications

    NARCIS (Netherlands)

    Kloosterman, J.; Kregting, R.; Erinc, M.; Driel, W.D. van

    2013-01-01

    Lighting is an advancing phenomenon both on the technology and on the market level due to the rapid development of the solid-state lighting technology. The interest in solder joint reliability has increased by the introduction of the so-called high brightness leadless type of packages. Solder joint

  2. High power vertical stacked and horizontal arrayed diode laser bar development based on insulation micro-channel cooling (IMCC) and hard solder bonding technology

    Science.gov (United States)

    Wang, Boxue; Jia, Yangtao; Zhang, Haoyu; Jia, Shiyin; Liu, Jindou; Wang, Weifeng; Liu, Xingsheng

    2018-02-01

    An insulation micro-channel cooling (IMCC) has been developed for packaging high power bar-based vertical stack and horizontal array diode lasers, which eliminates many issues caused in its congener packaged by commercial copper formed micro-channel cooler(MCC), such as coefficient of thermal expansion (CTE) mismatch between cooler and diode laser bar, high coolant quality requirement (DI water) and channel corrosion and electro-corrosion induced by DI water if the DI-water quality is not well maintained The IMCC cooler separates water flow route and electrical route, which allows tap-water as coolant without electro-corrosion and therefore prolongs cooler lifetime dramatically and escalated the reliability of these diode lasers. The thickness of ceramic and copper in an IMCC cooler is well designed to minimize the CTE mismatch between laser bar and cooler, consequently, a very low "SMILE" of the laser bar can be achieved for small fast axis divergence after collimation. In additional, gold-tin hard solder bonding technology was also developed to minimize the risk of solder electromigration at high current density and thermal fatigue under hard-pulse operation mode. Testing results of IMCC packaged diode lasers are presented in this report.

  3. Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

    Science.gov (United States)

    Hayashi, Nobuhiko; Terauchi, Masaharu; Aya, Youichirou; Kanayama, Shutetsu; Nishitani, Hikaru; Nakagawa, Tohru; Takase, Michihiko

    2017-09-01

    We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.

  4. Assessment of potential solder candidates for high temperature applications

    DEFF Research Database (Denmark)

    of the package with different solders of different melting temperatures. High Pb containing alloys where the lead levels can be above 85% by weight, is one of the solders currently being used in this technology. Responding to market pressure i.e. need for green electronic products there is now an increasing......Multi-Chip module (MCM) technology is a specialized electronic packaging technology recently gaining momentum due to the miniaturization drive in the microelectronics industry. The step soldering approach is being employed in the MCM technology. This method is used to solder various levels...... 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...

  5. Photonic flash soldering of thin chips and SMD components on foils for flexible electronics

    NARCIS (Netherlands)

    Ende, D.A. van den; Hendriks, R.; Cauchois, R.; Kusters, R.H.L.; Cauwe, M.; Groen, W.A.; Brand, J. van den

    2014-01-01

    Ultrathin bare die chips and small-size surface mount device components were successfully soldered using a novel roll-to-roll compatible soldering technology. A high-power xenon light flash was used to successfully solder the components to copper tracks on polyimide (PI) and polyethylene

  6. [Solder melting torches].

    Science.gov (United States)

    Cubero Postigo, G

    1988-11-01

    In this study about melting and torchs employed in solder in fixed prosthodontics, it's analysed the accurate melting, adequate quantity, as well as protection of adjacent tissues with an accurate anti-melting. The torch chosen is the oxyacetylene burner, because its greater calorific power.

  7. 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.

  8. 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 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...

  9. High-temperature lead-free solder alternatives

    DEFF Research Database (Denmark)

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

    2011-01-01

    For lead-free solders in the high-temperature regime, unfortunately, a limited number of alloying systems are available. These are Bi based alloys, gold involving alloys and Zn–Al based alloys. Based on these systems, possible candidate alloys were designed to have a melting range between 270°C...... and 350°C. Each has its own superior characteristics as well as some drawbacks however none of them can fulfill all the requirements to replace the current high-lead content solders. Even the alternative technologies that are currently being developed cannot address several critical issues of high......-temperature soldering. Therefore, further research and development of high-temperature lead-free soldering is obviously needed....

  10. Certified Satisfiability Modulo Theories (SMT) Solving for System Verification

    Science.gov (United States)

    2017-01-01

    and that generated it. In general, this recursive proof-tree generation process always terminates because each learned...Clauses are encoded essentially as nil- terminated lists of literals. They are built with the constructors , for the empty clause, and... Math . Artif. Intell., vol. 65, no. 4, pp. 329–372, 2012. [31] F. Besson, P. Fontaine, and L. Théry, “A Flexible Proof Format for SMT: a Proposal,” in

  11. FY 2017-Progress Report on the Design and Construction of the Sodium Loop SMT-3

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Lab. (ANL), Argonne, IL (United States); Momozaki, Y. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-09-01

    This report provides an update on the design of a forced-convection sodium loop to be used for the evaluation of sodium compatibility of advanced Alloy 709 with emphasis on long term exposures of tensile, creep, fatigue, creep fatigue, and fracture toughness ASTM-size specimens in support of ASME Code qualification and NRC licensing. The report is a deliverable (Level 4) in FY17 (M4AT-17AN1602094), under the Work Package AT-17AN160209, “Sodium Compatibility” performed by Argonne National Laboratory (ANL), as part of the Advanced Materials Program for the Advanced Reactor Technology. This work package enables the development of advanced structural materials by providing corrosion, microstructure, and mechanical property data from the standpoint of sodium compatibility of advanced structural alloys. The first sodium loop (SMT-1) with a single tank was constructed in 2011 at ANL and has been in operation for exposure of subsize sheet specimens of advanced alloys at a single temperature. The second sodium loop with dual tanks (SMT-2) was constructed in 2013 and has been in operation for the exposure of subsize sheet specimens of advanced alloys at two different temperatures. The current loop (SMT-3) has been designed to incorporate sufficient chamber capacity to expose a large number of ASTM-size specimens to evaluate the sodium effects on tensile, creep, fatigue, creep-fatigue, and fracture toughness properties, in support of ASME Code Qualification and USNRC Licensing. The design of individual components for the third sodium loop SMT-3 is almost complete. The design also has been sent to an outside vendor for piping analysis to be in compliance with ASME Code. A purchase order has been placed with an outside vendor for the fabrication of major components such as the specimen exposure tanks. However, we have contracted with another vendor to establish the piping design in compliance with ASME design codes. The piping design was completed in FY2017 and the

  12. 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

  13. Development of lead-free solders for high-temperature applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek

    -temperature applications. Unfortunately, even the substitute technologies that are currently being developed cannot address several critical issues of high-temperature soldering. Therefore, further research and development of high-temperature lead-free soldering is obviously needed. It is hoped that this thesis can serve...

  14. Microbial leaching of waste solder for recovery of metal.

    Science.gov (United States)

    Hocheng, H; Hong, T; Jadhav, U

    2014-05-01

    This study proposes an environment-friendly bioleaching process for recovery of metals from solders. Tin-copper (Sn-Cu), tin-copper-silver (Sn-Cu-Ag), and tin-lead (Sn-Pb) solders were used in the current study. The culture supernatant of Aspergillus niger removed metals faster than the culture supernatant of Acidithiobacillus ferrooxidans. Also, the metal removal by A. niger culture supernatant is faster for Sn-Cu-Ag solder as compared to other solder types. The effect of various process parameters such as shaking speed, temperature, volume of culture supernatant, and increased solder weight on bioleaching of metals was studied. About 99 (±1.75) % metal dissolution was achieved in 60 h, at 200-rpm shaking speed, 30 °C temperature, and by using 100-ml A. niger culture supernatant. An optimum solder weight for bioleaching was found to be 5 g/l. Addition of sodium hydroxide (NaOH) and sodium chloride (NaCl) in the bioleached solution from Sn-Cu-Ag precipitated tin (85 ± 0.35 %) and silver (80 ± 0.08 %), respectively. Passing of hydrogen sulfide (H2S) gas at pH 8.1 selectively precipitated lead (57.18 ± 0.13 %) from the Sn-Pb bioleached solution. The proposed innovative bioleaching process provides an alternative technology for recycling waste solders to conserve resources and protect environment.

  15. Providing Morphological Information for SMT Using Neural Networks

    Directory of Open Access Journals (Sweden)

    Passban Peyman

    2017-06-01

    Full Text Available Treating morphologically complex words (MCWs as atomic units in translation would not yield a desirable result. Such words are complicated constituents with meaningful subunits. A complex word in a morphologically rich language (MRL could be associated with a number of words or even a full sentence in a simpler language, which means the surface form of complex words should be accompanied with auxiliary morphological information in order to provide a precise translation and a better alignment. In this paper we follow this idea and propose two different methods to convey such information for statistical machine translation (SMT models. In the first model we enrich factored SMT engines by introducing a new morphological factor which relies on subword-aware word embeddings. In the second model we focus on the language-modeling component. We explore a subword-level neural language model (NLM to capture sequence-, word- and subword-level dependencies. Our NLM is able to approximate better scores for conditional word probabilities, so the decoder generates more fluent translations. We studied two languages Farsi and German in our experiments and observed significant improvements for both of them.

  16. 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.

  17. Preliminary test results in support of integrated EPP and SMT design methods development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sham, T. -L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-09

    The proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology consists of incorporating a SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid using the creep-fatigue interaction diagram (the D diagram) and to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed code rules and to verify their applicability, a series of thermomechanical tests have been initiated. One test concept, the Simplified Model Test (SMT), takes into account the stress and strain redistribution in real structures by including representative follow-up characteristics in the test specimen. The second test concept is the two-bar thermal ratcheting tests with cyclic loading at high temperatures using specimens representing key features of potential component designs. This report summaries the previous SMT results on Alloy 617, SS316H and SS304H and presents the recent development on SMT approach on Alloy 617. These SMT specimen data are also representative of component loading conditions and have been used as part of the verification of the proposed integrated EPP and SMT design methods development. The previous two-bar thermal ratcheting test results on Alloy 617 and SS316H are also summarized and the new results from two bar thermal ratcheting tests on SS316H at a lower temperature range are reported.

  18. Alloying influences on low melt temperature SnZn and SnBi solder alloys for electronic interconnections

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Guang [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland); Department of Civil Engineering and Materials Science, University of Limerick (Ireland); Wilding, Ian J. [Henkel Ltd, Hemel Hempstead (United Kingdom); Collins, Maurice N., E-mail: Maurice.collins@ul.ie [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland)

    2016-04-25

    Due to its commercial potential and the technological challenges associated with processing, low temperature soldering is a topic gaining widespread interest in both industry and academia in the application space of consumer and “throw away” electronics. This review focuses on the latest metallurgical alloys, tin zinc (Sn–Zn) and tin bismuth (Sn–Bi), for lower temperature processed electronic interconnections. The fundamentals of solder paste production and flux development for these highly surface active metallic powders are introduced. Intermetallic compounds that underpin low temperature solder joint production and reliability are discussed. The influence of alloying on these alloys is described in terms of critical microstructural changes, mechanical properties and reliability. The review concludes with an outlook for next generation electronic interconnect materials. - Highlights: • Review of the latest advances in Sn–Zn and Sn–Bi solder alloys. • Technological developments underpinning low temperature soldering. • Micro alloying influences on next generation interconnect materials.

  19. 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...

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

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Ambat, Rajan

    2009-01-01

    , corrosion investigation was carried out on potential ternary lead-free candidate alloys based on these binary alloys for high temperature applications. These promising ternary candidate alloys were determined by the CALPHAD approach based on the solidification criterion and the nature of the phases...... predicted in the bulk solder. This work reveals that the Au-Sn based candidate alloys close to the eutectic composition (20 wt. % Sn) are more corrosion resistant than the Au-Ge based ones.......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...

  1. Electronic hidden solder joint geometry characterization

    Science.gov (United States)

    Hsieh, Sheng-Jen

    2009-05-01

    To reduce the size of electronic equipment, multi-layer printed circuit board structures have become popular in recent years. As a result, the inspection of hidden solder joints between layers of boards has become increasingly difficult. Xray machines have been used for ball grid array (BGA) and hidden solder joint inspection; however, the equipment is costly and the inspection process is time consuming. In this paper, we investigate an active thermography approach to probing solder joint geometry. A set of boards having the same number of solder joints and amount of solder paste (0.061 g) was fabricated. Each solder joint had a different geometry. A semi-automated system was built to heat and then transfer each board to a chamber where an infrared camera was used to scan the board as it was cooling down. Two-thirds of the data set was used for model development and one-third was used for model evaluation. Both artificial neural network (ANN) and binary logistic regression models were constructed. Results suggest that solder joints with more surface area cool much faster than those with less surface area. In addition, both modeling approaches are consistent in predicting solder geometry; ANN had 85% accuracy and the regression model had 80%. This approach can potentially be used to test for cold solder joints prior to BGA assembly, since cold solder joints may have air gaps between the joint and the board and air is a poor heat conductor. Therefore, a cold solder joint may have a slower cooling rate than a normal one.

  2. Optimization on laser soldering parameters onto lead-free solder joint

    Science.gov (United States)

    Nabila, T. J.; Idris, S. R. A.; Ishak, M.

    2017-09-01

    This paper presents the results of optimization on laser soldering parameters onto lead free solder joint. The objective of this study is to determine the laser power needed and scanning time required to produce a high quality of solder joint. Laser soldering was selected due to its rapid and controllable selective process as well as suitable for temperature sensitive assemblies, which is very desirable nowadays as compared to time consuming process such as casting. A fibre laser with 200W was used in this study to form a joining between lead free solder wire and copper board. However, a continuous laser power was ranged between 48 to 60W to create joining. Before that, flux was also applied prior to laser soldering for uniform heat distribution throughout the solder volume. Lead free solder wire with the size of 1.0mm diameter was formed into several shapes including straight line-shape with 20mm in length, and spiral-shape with 6mm diameter, in order to capture and disperse the heat evenly. Results showed that laser power ranged from 48W to 60W with 3.5 to 4.5s duration was found to be suitable for lead free solder wire with spiral-shape condition. Besides, the wetting angle was also in optimal when the laser power was increased The optimized fibre laser parameters obtained in this study will be used for future reference in performing a laser soldering between solder alloy copper board.

  3. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... produced and characterized for possible replacement of Tin-Lead solders. The solder alloys produced are: 91Sn–9Zn, 60Sn–40Zn, 42Sn–58Bi, and 90Sn–10Bi. Tin-lead ... processing equipment and the use of lead pipes for drinking water is now discouraged due to the possibility of lead poisoning from ...

  4. 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.

  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. Using active thermography and modified SVM for intelligent diagnosis of solder bumps

    Science.gov (United States)

    Wei, Wei; Wei, Li; Nie, Lei; Su, Lei; Lu, Xiangning

    2015-09-01

    Solder bump technology has been used extensively in microelectronic packaging. But defect inspection becomes increasingly difficult due to the decrease of solder bumps in dimension and pitch. To overcome the shortages of traditional methods, we have developed an intelligent system using the active thermography for defects inspection of the solder bumps. A modified support vector machine (M-SVM) was investigated to solve the problem of small sample size in solder bumps classification. The chip SFA1 and SFA2 were chosen as the test vehicles. Captured thermal images were preprocessed using the improved wiener filter and moving average technique to remove the peak noise. The principal component analysis (PCA) algorithm was then adopted to reconstruct the thermal image, in which the hot spots were segmented. The statistical features corresponding to every solder bump were extracted and input into the M-SVM for solder bumps classification. The defective bumps w distinguished from the good bumps, which proves that the intelligent system using the modified SVM is effective for defects inspection in microelectronic packages.

  7. 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.

  8. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    Simulation and experimental results show that the PTH solder profiles of the two soldering processes are almost identical. The effect of PCB thickness on PTH voiding is also discussed. Keywords. Pin through hole (PTH); adjustable fountain wave soldering; wave soldering; printed circuit board (PCB); vertical fill; simulation.

  9. Turbo-SMT: Parallel Coupled Sparse Matrix-Tensor Factorizations and Applications

    Science.gov (United States)

    Papalexakis, Evangelos E.; Faloutsos, Christos; Mitchell, Tom M.; Talukdar, Partha Pratim; Sidiropoulos, Nicholas D.; Murphy, Brian

    2016-01-01

    How can we correlate the neural activity in the human brain as it responds to typed words, with properties of these terms (like ’edible’, ’fits in hand’)? In short, we want to find latent variables, that jointly explain both the brain activity, as well as the behavioral responses. This is one of many settings of the Coupled Matrix-Tensor Factorization (CMTF) problem. Can we enhance any CMTF solver, so that it can operate on potentially very large datasets that may not fit in main memory? We introduce Turbo-SMT, a meta-method capable of doing exactly that: it boosts the performance of any CMTF algorithm, produces sparse and interpretable solutions, and parallelizes any CMTF algorithm, producing sparse and interpretable solutions (up to 65 fold). Additionally, we improve upon ALS, the work-horse algorithm for CMTF, with respect to efficiency and robustness to missing values. We apply Turbo-SMT to BrainQ, a dataset consisting of a (nouns, brain voxels, human subjects) tensor and a (nouns, properties) matrix, with coupling along the nouns dimension. Turbo-SMT is able to find meaningful latent variables, as well as to predict brain activity with competitive accuracy. Finally, we demonstrate the generality of Turbo-SMT, by applying it on a Facebook dataset (users, ’friends’, wall-postings); there, Turbo-SMT spots spammer-like anomalies. PMID:27672406

  10. Turbo-SMT: Parallel Coupled Sparse Matrix-Tensor Factorizations and Applications.

    Science.gov (United States)

    Papalexakis, Evangelos E; Faloutsos, Christos; Mitchell, Tom M; Talukdar, Partha Pratim; Sidiropoulos, Nicholas D; Murphy, Brian

    2016-08-01

    How can we correlate the neural activity in the human brain as it responds to typed words, with properties of these terms (like 'edible', 'fits in hand')? In short, we want to find latent variables, that jointly explain both the brain activity, as well as the behavioral responses. This is one of many settings of the Coupled Matrix-Tensor Factorization (CMTF) problem. Can we enhance any CMTF solver, so that it can operate on potentially very large datasets that may not fit in main memory? We introduce Turbo-SMT, a meta-method capable of doing exactly that: it boosts the performance of any CMTF algorithm, produces sparse and interpretable solutions, and parallelizes any CMTF algorithm, producing sparse and interpretable solutions (up to 65 fold ). Additionally, we improve upon ALS, the work-horse algorithm for CMTF, with respect to efficiency and robustness to missing values. We apply Turbo-SMT to BrainQ, a dataset consisting of a (nouns, brain voxels, human subjects) tensor and a (nouns, properties) matrix, with coupling along the nouns dimension. Turbo-SMT is able to find meaningful latent variables, as well as to predict brain activity with competitive accuracy. Finally, we demonstrate the generality of Turbo-SMT, by applying it on a Facebook dataset (users, 'friends', wall-postings); there, Turbo-SMT spots spammer-like anomalies.

  11. Effect of Solder Flux Residues on Corrosion of Electronics

    DEFF Research Database (Denmark)

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

    2009-01-01

    that no cleaning after the solder process is required. In some cases, however, this statement is not correct. Experiments with ‘No Clean’ wave solder flux have been performed, and the results show, that the solder temperature plays an important role; temperatures below 170°C cause more flux residues than solder......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...... of dust, which can act as a humidity absorber. The experiments have been made on SnPb wave solder flux, later experiments will show if the problems are less for Lead-free reflow and wave soldering, because the solder temperature is about 20°C higher. Furthermore an example of failure after humidity...

  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. Induction soldering of photovoltaic system components

    Science.gov (United States)

    Kumaria, Shashwat; de Leon, Briccio

    2015-11-17

    A method comprises positioning a pair of photovoltaic wafers in a side-by-side arrangement. An interconnect is placed on the pair of wafers such that the interconnect overlaps both wafers of the pair, solder material being provided between the interconnect and the respective wafers. A solder head is then located adjacent the interconnect, and the coil is energized to effect inductive heating of the solder material. The solder head comprises an induction coil shaped to define an eye, and a magnetic field concentrator located at least partially in the eye of the coil. The magnetic field concentrator defines a passage extending axially through the eye of the coil, and may be of a material with a high magnetic permeability.

  14. Feasibility studies for laser solder neurorrhaphy

    Science.gov (United States)

    Bass, Lawrence S.; Moazami, Nader; Avellino, Anthony; Trosaborg, W.; Treat, Michael R.

    1994-09-01

    We present a novel technique of nerve repair attempting to reduce scarring and improve alignment. A laser solder composed of albumin, hyaluronate, and indocyanine green dye (peak absorbance 805 nm) was used. After applying solder to the anastomotic site, nerve ends can be precisely aligned and sealed in place using an 810 nm diode laser. Transected sciatic nerves in the rat were used as the experimental model. Laser repairs had approximately half the immediate strength of suture repairs (130 vs 280 g/cm2) but comparable strength by 7 days (270 vs 250 g/cm2). There was no dehiscence in either group. Thermal damage was confined to the solder and epineurium. At 90 days there was no difference in nerve conduction values or axon counts in suture or laser repairs. Histology was suggestive of a later stage of regeneration in the laser group. Laser soldering produces increased strength compared with traditional laser welding with less thermal injury.

  15. FY16 Progress Report on Test Results In Support Of Integrated EPP and SMT Design Methods Development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [RI Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-08-08

    The proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology consists of incorporating an SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid using the creep-fatigue interaction diagram (the D diagram) and to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed code rules and to verify their applicability, a series of thermomechanical tests have been initiated. This report presents the recent test results for Type 2 SMT specimens on Alloy 617, Pressurization SMT on Alloy 617, Type 1 SMT on Gr. 91, and two-bar thermal ratcheting test results on Alloy 617 with a new thermal loading profile.

  16. Modelling and Analysis for Cyber-Physical Systems: An SMT-based approach

    DEFF Research Database (Denmark)

    Dung, Phan Anh

    Calculus has shown its potential as a domain specific language in a Smart Meter case study. Moreover, counting semantics has proven useful in connection with tool-based support for Duration Calculus. To extend SMT techniques towards better support for analysis of CPS, we proposed algorithms for handling...

  17. Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

    Science.gov (United States)

    Acharya, Celin; Blindauer, Claudia A

    2016-02-15

    Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

  18. Analyzing toys models of Arabidopsis and Drosphila using Z3 SMT-LIB

    Science.gov (United States)

    Rodríguez Vega, Martín.

    2014-05-01

    Toy models for the Arabidopsis Thaliana flower and the Drosophila are analyzed using Microsoft SMT-Solver Z3 with the SMT-LIB language. The models are formulated as Boolean networks which describe the metabolic cycles for Arabidopsis and Drosophila. The dynamic activation of the different bio macromolecules is described by the variables and laws of Boolean transition. Specifically, bitvectors and assertions, which describe the change of state of bitvectors from a sampling time to the next, are used. The dynamic feasibility problem of the biological network is translated to a Boolean satisfiability problem. The corresponding dynamic attractors are represented as a model of satisfiability. The Z3 software allows all required computations in a friendly and efficient manner. It is expected that the SMT-solvers, such as Z3, will become a routine tool in system biology and that they will provide bio-nanosystem design techniques. As a line for future research, the study of the models for Arabidopsis and Drosophila using different SMT-solvers such as CVC4, Mathsat and Yices, is proposed.

  19. The smt-0 mutation which abolishes mating-type switching in fission yeast is a deletion

    DEFF Research Database (Denmark)

    Styrkársdóttir, U; Egel, R; Nielsen, O

    1993-01-01

    Mating-type switching in the fission yeast, S. pombe, is initiated by a DNA double-strand break (DSB) between the mat1 cassette and the H1 homology box. The mat1-cis-acting mutant, smt-0, abolishes mating-type switching and is shown here to be a 263-bp deletion. This deletion starts in the middle...

  20. Report on FY17 testing in support of integrated EPP-SMT design methods development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli . [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sham, T. -L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The goal of the proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology is to incorporate a SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. The purpose of this methodology is to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed methodology and to verify the applicability of the code rules, thermomechanical tests continued in FY17. This report presents the recent test results for Type 1 SMT specimens on Alloy 617 with long hold times, pressurization SMT on Alloy 617, and two-bar thermal ratcheting test results on SS316H at the temperature range of 405 °C to 705 °C. Preliminary EPP strain range analysis on the two-bar tests are critically evaluated and compared with the experimental results.

  1. 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.

  2. Zn2+-Inducible Expression Platform for Synechococcus sp. Strain PCC 7002 Based on the smtA Promoter/Operator and smtB Repressor.

    Science.gov (United States)

    Pérez, Adam A; Gajewski, John P; Ferlez, Bryan H; Ludwig, Marcus; Baker, Carol S; Golbeck, John H; Bryant, Donald A

    2017-02-01

    Synechococcus sp. strain PCC 7002 has been gaining significance as both a model system for photosynthesis research and for industrial applications. Until recently, the genetic toolbox for this model cyanobacterium was rather limited and relied primarily on tools that only allowed constitutive gene expression. This work describes a two-plasmid, Zn 2+ -inducible expression platform that is coupled with a zurA mutation, providing enhanced Zn 2+ uptake. The control elements are based on the metal homeostasis system of a class II metallothionein gene (smtA 7942 ) and its cognate SmtB 7942 repressor from Synechococcus elongatus strain PCC 7942. Under optimal induction conditions, yellow fluorescent protein (YFP) levels were about half of those obtained with the strong, constitutive phycocyanin (cpcBA 6803 ) promoter of Synechocystis sp. strain PCC 6803. This metal-inducible expression system in Synechococcus sp. strain PCC 7002 allowed the titratable gene expression of YFP that was up to 19-fold greater than the background level. This system was utilized successfully to control the expression of the Drosophila melanogaster β-carotene 15,15'-dioxygenase, NinaB, which is toxic when constitutively expressed from a strong promoter in Synechococcus sp. strain PCC 7002. Together, these properties establish this metal-inducible system as an additional useful tool that is capable of controlling gene expression for applications ranging from basic research to synthetic biology in Synechococcus sp. strain PCC 7002. This is the first metal-responsive expression system in cyanobacteria, to our knowledge, that does not exhibit low sensitivity for induction, which is one of the major hurdles for utilizing this class of genetic tools. In addition, high levels of expression can be generated that approximate those of established constitutive systems, with the added advantage of titratable control. Together, these properties establish this Zn 2+ -inducible system, which is based on the

  3. Microstructural evolution of eutectic Au-Sn solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Geon [Univ. of California, Berkeley, CA (United States)

    2002-05-01

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  4. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    PTH components, such as the pin, resistor, and light emit- ting diode, are inserted into the PCB hole and carried by the conveyor to the soldering zone. The soldering process begins when a mechanical bond is formed between PTH and the PCBs pass- ing through the molten solder. This study investigated the effect of PCB ...

  5. 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.

  6. 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.

  7. [Clinical study of SMT-Ⅱ video laryngoscope with difficult airway intubation in emergency department].

    Science.gov (United States)

    Yu, J H; Wang, Y

    2017-07-01

    Objective: To observe the clinical feasibility and security of SMT-Ⅱ video laryngoscope in difficult airway intubation in emergency department. Methods: This study took 90 adults with difficult airway who were admitted to the rescue room of Jingxi court of Beijing Chao-Yang Hospital, Capital Medical University from January 2015 to December 2016.The patients were randomly divided into 2 groups(SMT-Ⅱ video laryngoscope group: n =45, Macintosh direct laryngoscope group: n =45), which were treated with endotracheal intubation and ventilator assisted ventilation.The evaluation of difficult mask ventilation(DMV) independent risk factor score, Wlison score, Cormack-Lehane grade, mouth opening, thyromental distance, visualization of the glottis, time for laryngoscopy, time for tracheal intubation, first-pass success rate of intubation, complications, mean arterial pressure(MAP) and heart rate(HR) before induction, after laryngoscopy, after induction, after intubation 5 minutes, 10 minutes were recorded.ANOVA, t -test, Chi-square test was used to analyze differences data, respectively. Results: There was no significant difference between the two groups in terms of gender, age, height, weight and other general data, mouth opening, DMV independent risk factor score, Wlison score, and thyromental distance(χ(2)=0.045, t =-0.367, t =0.684, t =0.511, t =0.330, t =-0.724, t =1.219, t =1.034, all P >0.05). A Cormack-Lehane grade Ⅰ or Ⅱ view were 44 cases in SMT-Ⅱ video laryngoscope group and 14 cases in Macintosh direct laryngoscope group. It significantly improved with the use of SMT- Ⅱ video laryngoscope, compared with Macintosh direct laryngoscope(χ(2)=52.096, P <0.01). The time to best view was shorter in SMT-Ⅱ video laryngoscope group compared to that in Macintosh direct laryngoscope group with (15.0±1.0) seconds vs . (24.2±3.4) seconds( t =-26.319, P <0.05). The tube passage time was shorter with SMT-Ⅱ video laryngoscope (31.6±4.3) seconds vs . (12.7±0

  8. Intelligent laser soldering inspection and process control

    Science.gov (United States)

    Vanzetti, Riccardo

    1987-01-01

    Component assembly on printed circuitry keeps making giant strides toward denser packaging and smaller dimensions. From a single layer to multilayer, from through holes to surface mounted components and tape applied bonds, unrelenting progress results in new, difficult problems in assembling, soldering, inspecting and controlling the manufacturing process of the new electronics. Among the major problems are the variables introduced by human operators. The small dimensions and the tight assembly tolerances are now successfully met by machines which are faster and more precise than the human hand. The same is true for soldering. But visual inspection of the solder joints is now so severely limited by the ever shrinking area accessible to the human eye that the inspector's diagnosis cannot be trusted any longer. Solutions to correcting these problems are discussed.

  9. Influence of nickel–phosphorus surface roughness on wettability and pores formation in solder joints for high power electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Vivet, L., E-mail: laurent.vivet@valeo.com [Valeo, Group Electronic Expertise and Development Services, 2 rue André Boulle, 94046 Créteil (France); Joudrier, A.-L. [Institut Lavoisier de Versailles, UMR CNRS 8180, 45 Avenue des Etats-Unis, 78035 Versailles (France); Tan, K.-L.; Morelle, J.-M. [Valeo, Group Electronic Expertise and Development Services, 2 rue André Boulle, 94046 Créteil (France); Etcheberry, A. [Institut Lavoisier de Versailles, UMR CNRS 8180, 45 Avenue des Etats-Unis, 78035 Versailles (France); Chalumeau, L. [Egide, Site industriel du Sactar, 85500 Bollène (France)

    2013-12-15

    Electroless nickel-high-phosphorus Ni–P plating is used as substrate coating in the electronic component technology. The ability to minimize pores formation in solder joints and the wettability of the Ni–P layer remain points of investigation. The qualities and the control of the physical and chemical properties of the deposits are essential for the reliability of the products. In this contribution it has been measured how a controlled change of one property of the Ni–P surface, its average roughness, changes the wettability of this surface before soldering completion, at ambient temperature and under ambient air, and how it contribute to change the amount and size of pores inside solder joints, after soldering completion. Before all, observations of the Ni–P surfaces using scanning electron microscopy have been achieved. Then the wettability has been measured through the determination of both the disperse and the polar fractions of the substrate surface tension, based on the measurements of the wetting angle for droplets of four different liquids, under ambient air and at room temperature (classical sessile drop technique). Finally the X-ray micro-radiography measurements of both the area fraction of pores and the size of the largest pore inside the solder joint of dice laser soldered on the studied substrate, using high melting temperature solder (300 °C, PbSnAg) have been achieved. This study clearly demonstrates that both the ability to minimize pores formation in solder joints and the wettability under ambient conditions of the Ni–P substrate decrease and become more variable when its average roughness increases. These effects can be explained considering the Cassie–Baxter model for rough surface wetting behaviour, completed by the model of heterogeneous nucleation and growth for gas bubbles inside a liquid.

  10. 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.

  11. Lead (Pb)-Free Solder Applications

    Energy Technology Data Exchange (ETDEWEB)

    VIANCO,PAUL T.

    2000-08-15

    Legislative and marketing forces both abroad and in the US are causing the electronics industry to consider the use of Pb-free solders in place of traditional Sn-Pb alloys. Previous case studies have demonstrated the satisfactory manufacturability and reliability of several Pb-free compositions for printed circuit board applications. Those data, together with the results of fundamental studies on Pb-free solder materials, have indicated the general feasibility of their use in the broader range of present-day, electrical and electronic components.

  12. Modeling and characteristic of the SMT Board Plug connector in high speed optical communication system

    Science.gov (United States)

    Wu, Haoran; Dong, Zhenzhen; Wang, Tanglin; Zhao, Heng; Feng, Junbo; Cui, Naidi; Teng, Jie; Guo, Jin

    2015-04-01

    Modeling and characteristic of the SMT Board Plug connector, which is used to connect micro optical transceiver to the main board, are proposed and analyzed in this paper. When the high speed signal transfers from the PCB of transceiver to main board through SMT Board Plug connector, the structure and material discontinuity of the connector causes insertion losses and impedance mismatches. This makes the performance of high speed digital system exacerbated. So it is essential to analyze the signal transfer characteristics of the connector and find out what factors affected the signal quality at the design stage of the digital system. To solve this problem, Ansoft's High Frequency Structure Simulator (HFSS), based on the finite element method, was employed to build accurate 3D models, analyze the effects of various structure parameters, and obtain the full-wave characteristics of the SMT Board Plug connectors in this paper. Then an equivalent circuit model was developed. The circuit parameters were extracted precisely in the frequency range of interests by using the curve fitting method in ADS software, and the result was in good agreement with HFSS simulations up to 8GHz with different structure parameters. At last, the measurement results of S-parameter and eye diagram were given and the S-parameters showed good coincidence between the measurement and HFSS simulation up to 4GHz.

  13. A Systematic Comparison of Data Selection Criteria for SMT Domain Adaptation

    Directory of Open Access Journals (Sweden)

    Longyue Wang

    2014-01-01

    Full Text Available Data selection has shown significant improvements in effective use of training data by extracting sentences from large general-domain corpora to adapt statistical machine translation (SMT systems to in-domain data. This paper performs an in-depth analysis of three different sentence selection techniques. The first one is cosine tf-idf, which comes from the realm of information retrieval (IR. The second is perplexity-based approach, which can be found in the field of language modeling. These two data selection techniques applied to SMT have been already presented in the literature. However, edit distance for this task is proposed in this paper for the first time. After investigating the individual model, a combination of all three techniques is proposed at both corpus level and model level. Comparative experiments are conducted on Hong Kong law Chinese-English corpus and the results indicate the following: (i the constraint degree of similarity measuring is not monotonically related to domain-specific translation quality; (ii the individual selection models fail to perform effectively and robustly; but (iii bilingual resources and combination methods are helpful to balance out-of-vocabulary (OOV and irrelevant data; (iv finally, our method achieves the goal to consistently boost the overall translation performance that can ensure optimal quality of a real-life SMT system.

  14. La stimulation magnétique transcrânienne (SMT) dans la recherche fondamentale et clinique en neuroscience

    Science.gov (United States)

    Valero-Cabré, Antoni; Pascual-Leone, Alvaro; Coubard, Olivier A.

    2011-01-01

    Introduction Les méthodes de stimulation cérébrale non invasives telles que la Stimulation Magnétique Transcrânienne (SMT) sont largement utilisées pour établir des inférences causales sur les relations entre cerveau et comportement. Des applications cliniques basées sur la SMT ont également été développées pour traiter des affections neurologiques ou psychiatriques comme la dépression, la dystonie, la douleur, les acouphènes ou les séquelles d’accident vasculaire cérébral. État des connaissances La SMT fonctionne en induisant de manière non invasive et de manière focale des courants électriques dans des régions corticales, modulant ainsi leur niveau d’activité de façon variable suivant la fréquence, le nombre d’impulsions, les intervalles et la durée de stimulation utilisés. S’agissant du cortex moteur, on sait par exemple que les patterns d’impulsions de SMT à basse fréquence ou ceux délivrées de manière continue tendent à déprimer l’activité locale, tandis que la SMT à haute fréquence et discontinus tend à la potentialiser. Outre ses effets locaux, la SMT peut aussi avoir des effets à distance sur les régions cérébrales, véhiculés par les connections anatomiques et qui dépendent de l’efficacité et du signe de ces connexions. Perspectives Dans le domaine de la recherche fondamentale et des applications thérapeutiques, l’utilisation efficace de la SMT requiert, cependant, la compréhension approfondie de ses principes opérationnels, de ses risques, de ses potentialités et de ses limites. Dans cet article, nous présentons les principes par lesquels opèrent les méthodes de stimulation cérébrale non invasive, et en particulier la SMT. Conclusion À l’issue de sa lecture, le lecteur sera en mesure de discuter de façon critique les études scientifiques et cliniques utilisant la SMT, ainsi que de concevoir des applications SMT suivant une hypothèse a priori dans le domaine de la recherche en

  15. 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...... for interconnecting the chip to a carrier in certain applications due to the unique properties of lead. Despite of all the beneficial attributes of lead, its potential environmental impact when the products are discarded to land fills has resulted in various legislatives to eliminate lead from the electronic products...... based on its notorious legacy as a major health hazard across the spectrum of human generations and cultures. Flip chip assembly is also now increasingly being used for the high-performance (H-P) systems. These H-P systems perform mission-critical operations and are expected to experience virtually...

  16. RECONSTRUCTING PALEO-SMT POSITIONS ON THE CASCADIA MARGIN USING MAGNETIC SUSCEPTIBILITY

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Joel [Univ. of New Hampshire, Durham, NH (United States); Phillips, Stephen [Univ. of New Hampshire, Durham, NH (United States)

    2014-09-30

    Magnetic susceptibility (κ) is a mixed signal in marine sediments, representing primary depositional and secondary diagenetic processes. Production of hydrogen sulfide via anaerobic oxidation of methane (AOM) at the sulfate-methane transition (SMT) and organoclastic sulfate reduction above the SMT can result in the dissolution of iron oxides, altering κ in sediments in methane gas and gas hydrate bearing regions. We investigated records of κ on the Cascadia margin (ODP Sites 1249 and 1252; IODP Site 1325) using a Zr/Rb heavy mineral proxy from XRF core scanning to identify intervals of primary detrital magnetic susceptibility and intervals and predict intervals affected by magnetite dissolutions. We also measured total sulfur content, grain size distributions, total organic carbon (TOC) content, and magnetic mineral assemblage. The upper 100 m of Site 1252 contains a short interval of κ driven by primary magnetite, with multiple intervals (> 90 m total) of decreased κ correlated with elevated sulfur content, consistent with dissolution of magnetite and re-precipitation of pyrite. In the upper 90 m of Site 1249, κ is almost entirely altered by diagenetic processes, with much of the low κ explained by a high degree of pyritization, and some intervals affected by the precipitation of magnetic iron sulfides. At Site 1325, κ between 0-20 and 51-73 mbsf represents primary mineralogy, and in the interval 24-51 mbsf, κ may be reduced due to pyritization. This integrated approach allows for a prediction of primary κ and the amount of κ loss at each site when compared to actual κ measurements. In the case of magnetite dissolution and full pyritization, these drawdowns in κ are supported by sulfur measurements, and the exposure times of magnetite to hydrogen sulfide can be modeled. The presence of methane and methane hydrates at these sites, as well as large variations in TOC content, suggest that the past migration rates of the SMT and variation in sulfate

  17. 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...

  18. Research of Joining Brittle Nonmetallic Materials with an Active Solder

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2014-01-01

    Full Text Available This paper deals with soldering high-purity brittle, nonmetallic materials such as SiO2, Si, and C (graphite. However, these materials exert poor wettability when using tin solder. Therefore, to reduce the wetting angle, an Sn solder alloyed with active Ti element was used. At a soldering temperature of 860°C and 15 min soldering time, the wetting angle on SiO2 ceramics was 30°, on silicon 42°, and on graphite 52°. All these wetting angles are below 90° and are acceptable for soldering. It has been shown that the bond in all joined materials (SiO2, Si, and C was of a diffusion character. New intermetallic products were formed on the boundary with nonmetal, thus allowing bond formation. The shear strength of SiO2 ceramics attained an average value of 17 MPa.

  19. Coarsening of the Sn-Pb Solder Microstructure in Constitutive Model-Based Predictions of Solder Joint Thermal Mechanical Fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Burchett, S.N.; Neilsen, M.K.; Rejent, J.A.; Frear, D.R.

    1999-04-12

    Thermal mechanical fatigue (TMF) is an important damage mechanism for solder joints exposed to cyclic temperature environments. Predicting the service reliability of solder joints exposed to such conditions requires two knowledge bases: first, the extent of fatigue damage incurred by the solder microstructure leading up to fatigue crack initiation, must be quantified in both time and space domains. Secondly, fatigue crack initiation and growth must be predicted since this metric determines, explicitly, the loss of solder joint functionality as it pertains to its mechanical fastening as well as electrical continuity roles. This paper will describe recent progress in a research effort to establish a microstructurally-based, constitutive model that predicts TMF deformation to 63Sn-37Pb solder in electronic solder joints up to the crack initiation step. The model is implemented using a finite element setting; therefore, the effects of both global and local thermal expansion mismatch conditions in the joint that would arise from temperature cycling.

  20. Effect of Metal Bond-Pad Configurations on the Solder Microstructure Development of Flip-Chip Solder Joints

    Science.gov (United States)

    Hu, Y. J.; Hsu, Y. C.; Huang, T. S.; Lu, C. T.; Wu, Albert T.; Liu, C. Y.

    2014-01-01

    Various microstructural zones were observed in the solidified solder of flip-chip solder joints with three metal bond-pad configurations (Cu/Sn/Cu, Ni/Sn/Cu, and Cu/Sn/Ni). The developed microstructures of the solidified flip-chip solder joints were strongly related to the associated metal bond pad. A hypoeutectic microstructure always developed near the Ni bond pad, and a eutectic or hypereutectic microstructure formed near the Cu pad. The effect of the metal bond pads on the solder microstructure alters the Cu solubility in the molten solder. The Cu content (solubility) in the molten Sn(Cu) solder eventually leads to the development of particular microstructures. In addition to the effect of the associated metal bond pads, the developed microstructure of the flip-chip solder joint depends on the configuration of the metal bond pads. A hypereutectic microstructure formed near the bottom Cu pad, and a eutectic microstructure formed near the top Cu pad. Directional cooling in the flip-chip solder joint during the solidification process causes the effects of the metal bond-pad configuration. Directional cooling causes the Cu content to vary in the liquid Sn(Cu) phase, resulting in the formation of distinct microstructural zones in the developed microstructure of the flip-chip solder joint.

  1. 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.

  2. 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.

  3. Report on FY15 Alloy 617 SMT Creep-Fatigue Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baird, Seth T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pu, Chao [Univ. of Tennessee, Knoxville, TN (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-22

    viability of the Alloy 617 Code Case, the use of the current elastic analysis based rules in Subsection NH for the evaluation of strain limits (a precursor for the creep-fatigue rules) and the creep-fatigue rules themselves have been deemed inappropriate for Alloy 617 at temperatures above 650C (Corum and Brass, 1991). The rationale for this exclusion is that at higher temperatures it is not feasible to decouple plasticity and creep, which is the basis for the current simplified rules. This temperature, 650C, is well below the temperature range of interest for this material for the High Temperature Gas Cooled Reactor (HTGR) as well as the VHTR. The only current alternative is, thus, a full inelastic analysis which requires sophisticated material models which have not yet been formulated and verified. To address the prohibition on the use of current methods at very high temperatures, proposed Code rules have been developed which are based on the use of elastic-perfectly plastic (E-PP) analysis methods and which are expected to be applicable to very high temperatures. To provide data to implement the proposed rules and to verify their application, a series of tests have been initiated. One test concept, the Simplified Model Test (SMT), takes into account the stress and strain redistribution in real structures by including representative follow-up characteristics in the test specimen. The correlation parameter between test and design is the elastically calculated strain, and the dependent test variable is the observed cycles to failure. Although the initial priority for the SMT approach is to generate data to support validation of the E-PP Code Case for evaluation of creep-fatigue damage, the broader goal of the SMT approach is to develop a methodology for evaluation of creep fatigue damage which is simpler to implement than the current complex rules and applicable to the full temperature range from ambient conditions to the very high temperature creep regime of 900-950C. Also

  4. 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

  5. Characterization of Solder Joint Reliability Using Cyclic Mechanical Fatigue Testing

    Science.gov (United States)

    Kim, Choong-Un; Bang, Woong-Ho; Xu, Huili; Lee, Tae-Kyu

    2013-10-01

    This article summarizes the mechanics of two mechanical fatigue methods, cyclic bending fatigue and shear fatigue, in inducing failure in solder joints in package assemblies, and it presents the characteristics of fatigue failures resulting from these methods using example cases of Sn-Pb eutectic and Sn-rich Pb-free solder alloys. Numerical simulation suggests that both testing configurations induce fatigue failure by the crack-opening mode. In the case of bending fatigue, the strain induced by the bending displacement is found to be sensitive to chip geometry, and it induces fatigue cracks mainly at the solder matrix adjacent to the printed circuit board interface. In case of shear fatigue, the failure location is firmly fixed at the solder neck, created by solder mask, where an abrupt change in the solder geometry occurs. Both methods conclude that the Coffin-Manson model is the most appropriate model for the isothermal mechanical fatigue of solder alloys. An analysis of fatigue characteristics using the frame of the Coffin-Manson model produces several insightful results, such as the reason why Pb-free alloys show higher fatigue resistance than Sn-Pb alloys even if they are generally more brittle. Our analysis suggests that it is related to higher work hardening. All these results indicate that mechanical fatigue can be an extremely useful method for fast screening of defective package structures and also in gaining a better understanding of fatigue failure mechanism and prediction of reliability in solder joints.

  6. Dry soldering with hot filament produced atomic hydrogen

    Science.gov (United States)

    Panitz, J.K.G.; Jellison, J.L.; Staley, D.J.

    1995-04-25

    A system is disclosed for chemically transforming metal surface oxides to metal that is especially, but not exclusively, suitable for preparing metal surfaces for dry soldering and solder reflow processes. The system employs one or more hot, refractory metal filaments, grids or surfaces to thermally dissociate molecular species in a low pressure of working gas such as a hydrogen-containing gas to produce reactive species in a reactive plasma that can chemically reduce metal oxides and form volatile compounds that are removed in the working gas flow. Dry soldering and solder reflow processes are especially applicable to the manufacture of printed circuit boards, semiconductor chip lead attachment and packaging multichip modules. The system can be retrofitted onto existing metal treatment ovens, furnaces, welding systems and wave soldering system designs. 1 fig.

  7. Using computer algebra and SMT-solvers to analyze a mathematical model of cholera propagation

    Science.gov (United States)

    Trujillo Arredondo, Mariana

    2014-06-01

    We analyze a mathematical model for the transmission of cholera. The model is already defined and involves variables such as the pathogen agent, which in this case is the bacterium Vibrio cholera, and the human population. The human population is divided into three classes: susceptible, infectious and removed. Using Computer Algebra, specifically Maple we obtain two equilibrium states: the disease free state and the endemic state. Using Maple it is possible to prove that the disease free state is locally asymptotically stable if and only if R0 1. Using the package Red-Log of the Computer algebra system Reduce and the SMT-Solver Z3Py it is possible to obtain numerical conditions for the model. The formula for the basic reproductive number makes a synthesis with all epidemic parameters in the model. Also it is possible to make numerical simulations which are very illustrative about the epidemic patters that are expected to be observed in real situations. We claim that these kinds of software are very useful in the analysis of epidemic models given that the symbolic computation provides algebraic formulas for the basic reproductive number and such algebraic formulas are very useful to derive control measures. For other side, computer algebra software is a powerful tool to make the stability analysis for epidemic models given that the all steps in the stability analysis can be made automatically: finding the equilibrium points, computing the jacobian, computing the characteristic polynomial for the jacobian, and applying the Routh-Hurwitz theorem to the characteristic polynomial. Finally, using SMT-Solvers is possible to make automatically checks of satisfiability, validity and quantifiers elimination being these computations very useful to analyse complicated epidemic models.

  8. FY16 Status Report on Development of Integrated EPP and SMT Design Methods

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, R. I. [R.I. Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    The goal of the Elastic-Perfectly Plastic (EPP) combined integrated creep-fatigue damage evaluation approach is to incorporate a Simplified Model Test (SMT) data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. The EPP methodology is based on the idea that creep damage and strain accumulation can be bounded by a properly chosen “pseudo” yield strength used in an elastic-perfectly plastic analysis, thus avoiding the need for stress classification. The original SMT approach is based on the use of elastic analysis. The experimental data, cycles to failure, is correlated using the elastically calculated strain range in the test specimen and the corresponding component strain is also calculated elastically. The advantage of this approach is that it is no longer necessary to use the damage interaction, or D-diagram, because the damage due to the combined effects of creep and fatigue are accounted in the test data by means of a specimen that is designed to replicate or bound the stress and strain redistribution that occurs in actual components when loaded in the creep regime. The reference approach to combining the two methodologies and the corresponding uncertainties and validation plans are presented. Results from recent key feature tests are discussed to illustrate the applicability of the EPP methodology and the behavior of materials at elevated temperature when undergoing stress and strain redistribution due to plasticity and creep.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Solder extrusion pressure bonding process and bonded products produced thereby

    Science.gov (United States)

    Beavis, Leonard C.; Karnowsky, Maurice M.; Yost, Frederick G.

    1992-01-01

    Production of soldered joints which are highly reliable and capable of surviving 10,000 thermal cycles between about -40.degree. C. and 110.degree. C. Process involves interposing a thin layer of a metal solder composition between the metal surfaces of members to be bonded and applying heat and up to about 1000 psi compression pressure to the superposed members, in the presence of a reducing atmosphere, to extrude the major amount of the solder composition, contaminants including fluxing gases and air, from between the members being bonded, to form a very thin, strong intermetallic bonding layer having a thermal expansion tolerant with that of the bonded members.

  14. The Power Sandwich : A Three-Dimensional Power Electronics Assembly Technology

    NARCIS (Netherlands)

    Josifovic, I.

    2014-01-01

    Current PCB power converter construction technologies are based on the utilization of nonstandardized building blocks. Utilization of passive components with various shapes, poor thermal properties and mixed technology mounting (THT and SMT) represents fundamental limit for reaching high power

  15. 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.

  16. Defects detecting method of lamp cap of single soldering lug

    Science.gov (United States)

    Cai, Jihe; Lv, Jidong

    2017-07-01

    In order to resolve the problems of low efficiency and large separating difference in fault detection of lamp holders with single soldering lug, an image-detection-based defect detection method is presented in this paper. The selected image is first preprocessed, where the possible area of soldering lug is cut in this preprocessing to narrow the scope for subsequent partition with the consideration that the smooth surface of metal at lamp holder and black insulation glass may reflect the light. Then, the soldering lug is extracted by a series of processing including clustering partition. Based on this, the defects are detected by regional marking, area comparison, circularity and coordinate deviation. The experiment results show that the designed method is simple and practical to detect main quality defects of lamp holder with single soldering lug correctly and efficiently.

  17. Metallurgical characterization of experimental Ag-based soldering alloys

    Directory of Open Access Journals (Sweden)

    Argyro Ntasi

    2014-10-01

    Conclusion: The experimental alloys tested demonstrated similar microstructures and melting ranges. Ga and Sn might be used as alternative to Cu and Zn to modify the selected properties of Ag based soldering alloys.

  18. Method of defence of solder surface from oxidization

    Directory of Open Access Journals (Sweden)

    Kurmashev Sh. D.

    2010-02-01

    Full Text Available Compositions are developed for defence of fusion solder from oxidization on the basis of mixture of glycerin, urea and powders of refractory oxides, carbides (Al2O3, TiO2, SIC, graphite. The offered compositions can be used for defence of fusion of solder from oxidization in the process of soludering and tinning of explorers, and also electric conclusions of elements of radio electronic apparatus by the method of immersion in stationary baths.

  19. 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.

  20. 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.

  1. The somatostatin receptor-targeted radiotherapeutic [90Y-DOTA-dPhe1,Tyr3]octreotide (90Y-SMT 487) eradicates experimental rat pancreatic CA 20948 tumours

    International Nuclear Information System (INIS)

    Stolz, B.; Weckbecker, G.; Smith-Jones, P.M.; Albert, R.; Raulf, F.; Bruns, C.

    1998-01-01

    Somatostatin receptor-expressing tumours are potential targets for therapy with radiolabelled somatostatin analogues. We have synthesized a number of such analogues in the past and identified [DOTA-dPhe 1 , Tyr 3 ]octreotide (SMT 487) as the most promising candidate molecule because of its advantageous properties in cellular and in vivo tumour models. In the current paper we describe the radiotherapeutic effect of yttrium-90 labelled SMT 487 in Lewis rats bearing the somatostatin receptor-positive rat pancreatic tumour CA 20948. SMT 487 binds with nanomolar affinity to both the human and the rat somatostatin receptor subtype 2 (sst 2 ) (human sst 2 IC 50 =0.9 nM, rat sst 2 IC 50 =0.5 nM). In vivo, 90 Y-SMT 487 distributed rapidly to the sst 2 expressing CA 20948 rat pancreatic tumour, with a tumour-to-blood ratio of 49.15 at 24 h post injection. A single intravenous administration of 10 mCi/kg 90 Y-SMT 487 resulted in a complete remission of the tumours in five out of seven CA 20948 tumour-bearing Lewis rats. No regrowth of the tumours occurred 8 months post injection. Control animals that were treated with 30 μg/kg of unlabelled SMT 487 had to be sacrificed 10 days post injection due to excessive growth or necrotic areas on the tumour surface. Upon re-inoculation of tumour cells into those rats that had shown complete remission, the tumours disappeared after 3-4 weeks of moderate growth without any further treatment. The present study shows for the first time the curative potential of 90 Y-SMT 487-based radiotherapy for somatostatin receptor-expressing tumours. Clinical phase I studies with yttrium-labelled SMT 487 have started in September 1997. (orig.)

  2. 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.

  3. [The dental soldering by means of high frequency induction heating (author's transl)].

    Science.gov (United States)

    Ichimaru, T; Kameda, T

    1977-04-01

    The authors examined the methods of high frequency induction soldering, especially Loop-method, other than the gas flame soldering which was known generally. The details which was done are: (1) about the form of induction coil, and the relative places of the coil and restrative appliance, and some supplementary appliances of them. (2) about strength of soldered joints of Co-Cr wire using silver solder and Pd-solder, and observation on the corrosion of soldered-joints by the scanning electron-microscope. (3) about the comparison of the characteristics of Co-Cr wire by means of high-frequency induction heating and gas-flame one. (4) about the examples of soldering of porcelain crown-bridge and clasp wire attached on the dental cast, and possibility of soldering techniques of them on the dental cast. The authors found that the high frequency induction method was preeminent from the other method on the point of (a) the characteristic of heated wire, (b) the strength of soldered joints, (c) the easiness of operating of them, and (d) the possibility of soldering using the high-melting point of Pd-solder, and the soldering of them on the dental cast. Therefore we can enough respect the application on the dental area of this apparatus and this techniques of the high-frequency induction soldering.

  4. Assessment of Exposure to Sensitizing Rosin-derived Compounds from Electronics Soldering

    National Research Council Canada - National Science Library

    Bowerbank, Christopher

    1998-01-01

    Exposure potential for rosin-derived compounds, including volatile and semivolatile organic compounds produced during electronics soldering operations using rosin-based fluxes and rosin core solders, was investigated...

  5. 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.

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

    OpenAIRE

    Mhiaoui, Souad

    2008-01-01

    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...

  7. Investigation Of Intermetallic Compounds In Sn-Cu-Ni Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Nagy E.

    2015-06-01

    Full Text Available Interfacial intermetallic compounds (IMC play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint.

  8. 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...

  9. 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...

  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. 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. Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

    Directory of Open Access Journals (Sweden)

    M. S. Abdul Aziz

    2014-01-01

    Full Text Available An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183°C < T < 643.15 K (370°C. Both solvers were coupled by the real time coupling software and mesh-based parallel code coupling interface during analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry.

  13. 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.

  14. Temperature-controlled two-wavelength laser soldering of tissues.

    Science.gov (United States)

    Gabay, Ilan; Abergel, Avraham; Vasilyev, Tamar; Rabi, Yaron; Fliss, Dan M; Katzir, Abraham

    2011-11-01

    Laser tissue soldering is a method for bonding of incisions in tissues. A biological solder is spread over the cut, laser radiation heats the solder and the underlying cut edges and the incision is bonded. This method offers many advantages over conventional techniques (e.g., sutures). Past researches have shown that laser soldering, using a single laser, does not provide sufficient strength for bonding of cuts in thick (>1 mm) tissues. This study introduces a novel method for laser soldering of thick tissues, under temperature control, using two lasers, emitting two different wavelengths. An experimental system was built, using two lasers: (i) a CO(2) laser, whose radiation heated the upper surface of the tissue and (ii) a GaAs laser that heated an albumin layer under the tissue. An infrared fiber-optic radiometer monitored the temperature of the tissue. All three devices were connected to a computer that controlled the process. A computer simulation was written to optimize the system parameters. The system was tested on tissue phantoms, to validate the simulation and ensure that both the upper and lower sides of the cut were heated, and that the temperature could be controlled on both sides. The system was then used ex vivo to bond longitudinal cuts of lengths ∼12 mm in the esophagi of large farm pigs. The theoretical simulations showed a good stabilization of the temperatures at the upper and lower tissue surfaces at the target values. Experiments on tissue phantom showed a good agreement with these simulations. Incisions in esophagi, removed from large farm pigs, were then successfully bonded. The mean burst pressure was ∼3.6 m of water. This study demonstrated the capability of soldering cuts in thick tissues, paving the way for new types of surgical applications. Copyright © 2010 Wiley Periodicals, Inc.

  15. 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.

  16. 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...... 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...... 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...

  17. Expression of the copper metallothionein CUPI from Saccharomyces cerevisiae in the cyanobacterium Synechococcus R2-PIM8(smtA).

    Science.gov (United States)

    McCormick, P M; Cannon, G C; Heinhorst, S

    1999-03-01

    The coding sequence for Saccharomyces cerevisiae copper metallothionein (CUPI), the protein responsible for enhanced sequestration of Cu2+ in yeast, was placed under the control of an inducible synthetic Escherichia coli promoter in the cyanobacterial vector pTrcIK. Strain R2-PIM8(smtA) of Synechococcus sp. PCC 7942 was transformed with the resulting construct pMcK2, and the yeast CUPI gene was integrated into its genome via homologous recombination. The pMcK2 plasmid directed the synthesis of a protein product of the expected size in an in vitro E. coli transcription/translation system. In the transgenic cyanobacteria, the integrated CUPI gene was transcribed and produced a protein product with the expected metallothionein characteristics, as determined by 109Cd2+ binding assays. At this level of expression, the yeast metallothionein, although functional, did not increase the tolerance range of the transgenic Synechococcus to Cu2+ or Cd2+ beyond that of the untransformed R2-PIM8(smtA).

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

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    The physics of failure for electrical components due to temperature loading is described. The main focus is on crack propagation in solder joints and damage accumulation models based on the Miner’s rule. Two models are proposed that describe the initial accumulated plastic strain depending...

  19. 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

  20. Horizon shells and BMS-like soldering transformations

    Science.gov (United States)

    Blau, Matthias; O'Loughlin, Martin

    2016-03-01

    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.

  1. 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.

  2. 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.

  3. Safety, Tolerability, and Pharmacokinetics of SMT C1100, a 2-Arylbenzoxazole Utrophin Modulator, following Single- and Multiple-Dose Administration to Pediatric Patients with Duchenne Muscular Dystrophy.

    Directory of Open Access Journals (Sweden)

    Valeria Ricotti

    Full Text Available SMT C1100 is a utrophin modulator being evaluated as a treatment for Duchenne muscular dystrophy (DMD. This study, the first in pediatric DMD patients, reports the safety, tolerability and PK parameters of single and multiple doses of SMT C1100, as well as analyze potential biomarkers of muscle damage.This multicenter, Phase 1 study enrolled 12 patients, divided equally into three groups (A-C. Group A were given 50 mg/kg on Days 1 and 11, and 50 mg/kg bid on Days 2 to 10. Group B and C received 100 mg/kg on Days 1 and 11; Group B and Group C were given 100 mg/kg bid and 100 mg/kg tid, respectively, on Days 2 to 10. A safety review was performed on all patients following the single dose and there was at least 2 weeks between each dose escalation, for safety and PK review. Adverse events (AEs were monitored throughout the study.Most patients experienced mild AEs and there were no serious AEs. Two patients required analgesia for pain (headache, ear pain and toothache. One patient experienced moderate psychiatric AEs (abnormal behaviour and mood swings. Plasma concentrations of SMT C1100 at Days 1 and 11 indicated a high degree of patient variability regardless of dose. Unexpectedly the SMT C1100 levels were significantly lower than similar doses administered to healthy volunteers in an earlier clinical study. In general, individual baseline changes of creatine phosphokinase, alanine aminotransferase, aspartate aminotransferase levels fell with SMT C1100 dosing.SMT C1100 was well tolerated in pediatric DMD patients.ClinicalTrials.gov NCT02383511.

  4. Safety, Tolerability, and Pharmacokinetics of SMT C1100, a 2-Arylbenzoxazole Utrophin Modulator, following Single- and Multiple-Dose Administration to Pediatric Patients with Duchenne Muscular Dystrophy.

    Science.gov (United States)

    Ricotti, Valeria; Spinty, Stefan; Roper, Helen; Hughes, Imelda; Tejura, Bina; Robinson, Neil; Layton, Gary; Davies, Kay; Muntoni, Francesco; Tinsley, Jonathon

    2016-01-01

    SMT C1100 is a utrophin modulator being evaluated as a treatment for Duchenne muscular dystrophy (DMD). This study, the first in pediatric DMD patients, reports the safety, tolerability and PK parameters of single and multiple doses of SMT C1100, as well as analyze potential biomarkers of muscle damage. This multicenter, Phase 1 study enrolled 12 patients, divided equally into three groups (A-C). Group A were given 50 mg/kg on Days 1 and 11, and 50 mg/kg bid on Days 2 to 10. Group B and C received 100 mg/kg on Days 1 and 11; Group B and Group C were given 100 mg/kg bid and 100 mg/kg tid, respectively, on Days 2 to 10. A safety review was performed on all patients following the single dose and there was at least 2 weeks between each dose escalation, for safety and PK review. Adverse events (AEs) were monitored throughout the study. Most patients experienced mild AEs and there were no serious AEs. Two patients required analgesia for pain (headache, ear pain and toothache). One patient experienced moderate psychiatric AEs (abnormal behaviour and mood swings). Plasma concentrations of SMT C1100 at Days 1 and 11 indicated a high degree of patient variability regardless of dose. Unexpectedly the SMT C1100 levels were significantly lower than similar doses administered to healthy volunteers in an earlier clinical study. In general, individual baseline changes of creatine phosphokinase, alanine aminotransferase, aspartate aminotransferase levels fell with SMT C1100 dosing. SMT C1100 was well tolerated in pediatric DMD patients. ClinicalTrials.gov NCT02383511.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Statistical and Physical Analyses of Electromigration-induced Failure in Lead-free Flip Chip Solder Joints

    Science.gov (United States)

    Choi, Daechul

    While electromigration in Al and Cu interconnects has been a persistent reliability issue in microelectronic industry, the trend of miniaturization in wireless and portable devices has caused electromigration in Pb-free flip chip solder joints to become another most challenging problem in electronic manufacturing industry. Up to now, the link between statistical and physical analyses of electromigration failure is weak, for example, we do not have a deep understanding of the reliability failure on the basis of kinetics of void nucleation and growth. In this study, we intend to make a direct link between Weibull distribution of Pb-free flip chip solder joint failure and Johnson-Mehl-Avrami's equations of phase transformations in terms of void nucleation and growth based on the assumption that void nucleation and propagation can be treated as a phase transformation induced by electromigration in the interconnect which is the main cause of failure in Pb-free solder joints. The statistical failure data from Pb-free flip chip solder joints were systematically collected by DAQ (data acquisition) program which measures in-situ resistance change due to a set of constant current densities stressed at a set of temperatures, and the data were statistically analyzed by Weibull distribution by using Minitab program. The test samples are from industry and the data are reproducible. It is worth mentioning that Weibull distribution function and Avrami's equation have the same mathematical form, and we shall develop the mathematical and physical links between them. Physical analysis of failure was supported by SEM (scanning electron microscope) examination and FIB (focused ion beam) of the cross-section of failed samples, 3-dimensional finite element simulation, and 3-D images obtained by using synchrotron radiation x-ray tomography at Advanced Light Source of Lawrence Berkeley National Laboratory. The final goal of this research is to establish a tool for critical analysis of

  10. Social Media Technology Management in College of Technology in Oman

    Science.gov (United States)

    Sharma, Himanshu; Pillai, Sunil Prakash

    2017-01-01

    Purpose: The purpose of this paper is to examine the impact of the constructs--utilitarian, hedonic and social value on the perceptions of the full-time instructors related to their social media technology (SMT) management for learning and teaching practices at workplace. Design/methodology/approach: A survey is used to gather the data from 180…

  11. 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.

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

    International Nuclear Information System (INIS)

    Chen, Haiyan; Peng, Jianke; Fu, Li; Wang, Xincheng; Xie, Yan

    2016-01-01

    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.

  13. Study on the Tensile Creep Behavior of Carbon Nanotubes-Reinforced Sn-58Bi Solder Joints

    Science.gov (United States)

    Yang, Li; Liu, Haixiang; Zhang, Yaocheng

    2018-01-01

    The microstructure and tensile creep behavior of plain Sn-58Bi solder and carbon nanotubes (CNTs)-reinforced composite solder joints were investigated. The stress exponent n under different stresses and the creep activation energy Q c under different temperatures of solder joints were obtained by an empirical equation. The results reveal that the microstructure of the composite solder joint is refined and the tensile creep resistance is improved by CNTs. The improvement of creep behavior is due to the microstructural change of the composite solder joints, since the CNTs could provide more obstacles for dislocation pile-up, which enhances the values of the stress exponent and the creep activation energy. The steady-state tensile creep rates of plain solder and composite solder joints are increased with increasing temperature and applied stress. The tensile creep constitutive equations of plain solder and composite solder joints are written as \\dot{ɛ }_{s1} = 14.94( {σ /G} )^{3.7} \\exp ( { - 81444/RT} ) and \\dot{ɛ }_{s2} = 2.5( {σ /G} )^{4.38} \\exp ( { - 101582/RT} ) , respectively. The tensile creep mechanism of the solder joints is the effects of lattice diffusion determined by dislocation climbing.

  14. 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.

  15. 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.

  16. Effect of ultrasonic vibration time on the Cu/Sn-Ag-Cu/Cu joint soldered by low-power-high-frequency ultrasonic-assisted reflow soldering.

    Science.gov (United States)

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

    2017-01-01

    Techniques to improve solder joint reliability have been the recent research focus in the electronic packaging industry. In this study, Cu/SAC305/Cu solder joints were fabricated using a low-power high-frequency ultrasonic-assisted reflow soldering approach where non-ultrasonic-treated samples were served as control sample. The effect of ultrasonic vibration (USV) time (within 6s) on the solder joint properties was characterized systematically. Results showed that the solder matrix microstructure was refined at 1.5s of USV, but coarsen when the USV time reached 3s and above. The solder matrix hardness increased when the solder matrix was refined, but decreased when the solder matrix coarsened. The interfacial intermetallic compound (IMC) layer thickness was found to decrease with increasing USV time, except for the USV-treated sample with 1.5s. This is attributed to the insufficient USV time during the reflow stage and consequently accelerated the Cu dissolution at the joint interface during the post-ultrasonic reflow stage. All the USV-treated samples possessed higher shear strength than the control sample due to the USV-induced-degassing effect. The shear strength of the USV-treated sample with 6s was the lowest among the USV-treated samples due to the formation of plate-like Ag 3 Sn that may act as the crack initiation site. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. ULTRASONIC SOLDERING OF Cu AND Al2O3 CERAMICS BY USE OF Bi-La AND Bi-Ag-La SOLDERS

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2016-04-01

    Full Text Available This work deals with the effect of solder alloying with a small amount of lanthanum on joint formation with metallic and ceramic substrate. The Bi-Ag – based solder with 2 wt.% lanthanum addition and Bi solder with 2 wt.% lanthanum addition were studied. Soldering was performed by afluxless process on the air, by activation with a power ultrasound. It was found out that, during the process of ultrasonic soldering, lanthanum is distributed on the boundary, both with the copper and the ceramic substrate, which enhances the joint formation. The bond with Al2O3 ceramics is of an adhesive character, without the formation of a new contact interlayer.

  18. 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...... by measuring the leak current using a twin platinum electrode setup. Localized extraction of residue was carried out using a commercial C3 extraction system. Results clearly show that the amount and distribution of flux residues are a function of the soldering process, and the level can be reduced...... by an appropriate cleaning. Selective soldering process generates significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under...

  19. 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...... out using a commercial critical contamination control extraction system. Findings – Results clearly show that the amount and distribution of flux residues are a function of the soldering process, and the level can be reduced by an appropriate cleaning. Selective soldering process generates...... significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under exposure to high humidity levels. Originality/value – Although...

  20. Study of Direct Bonding Ceramics with Metal Using Sn2La Solder

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2015-01-01

    Full Text Available The aim of this research was to study the direct bonding of ceramic materials, mainly Al2O3 and selected metals, with primary attention given to Cu substrate. Soldering was performed with Sn-based solder alloyed with 2% La. We found that the bond formation between Sn2La solder and Al2O3 occurs at the activation of lanthanum phases in solder by ultrasound. Lanthanum in the solder becomes oxidised in air during the soldering process. However, due to ultrasonic activation, the lanthanum particles are distributed to the boundary with ceramic material. A uniformly thin layer containing La, 1.5 µm in thickness, is formed on the boundary with Al2O3 material, ensuring both wetting and joint formation. The shear strength with Al2O3 ceramics is 7.5 MPa. Increased strength to 13.5 MPa was observed with SiC ceramics.

  1. 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.

  2. 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.

  3. 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.

  4. 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...... such as diffusivity, permeability, and solubility. In addition, the effect of a reflow soldering simulation on microstructural changes and onincrease of water uptake of the materials has been analysed...

  5. Nano Coated Lead Free Solders for Sustainable Electronic Waste Management

    Directory of Open Access Journals (Sweden)

    K. Arun Vasantha Geethan

    Full Text Available ABSTRACT Lead has been used in a wide range of applications, but in the past decades it became clear that its high toxicity could cause various problems. Studies indicate that exposure to high concentrations of lead can cause harmful damages to humans. To eliminate the usage of lead in electronic products as an initiative towards electronic waste management (e waste, lead free solders were produced with suitable methods by replacing lead. But lead free solders are not preferred as a substitute of lead because they are poor in their mechanical properties such as tensile strength, shear strength and hardness which are ultimately required for a material to resist failure.Nano-Structured materials and coatings offer the potential for Vital improvements in engineering properties based on improvements in physical and mechanical properties resulting from reducing micro structural features by factors of 100 to 1000 times compared to current engineering materials.

  6. Studies on inhibition of galvanic corrosion of lead based solders

    International Nuclear Information System (INIS)

    Perumareddi, R.; Sastri, V.S.; Elboujdaini, M.

    1999-01-01

    Exposure of Pb/Sn solder embedded in copper plates releases Pb into tap water and well water in excess of permissible level of 10 μg/L. Release of Pb has been inhibited by adding 40 ppm of silicate or 20 ppm of silicate and 20 ppm of phosphate to tap water and well water. XPS, electron microprobe and EDAX analysis of the solder surfaces show the surfaces deposits to be copper silicate and copper silicate and calcium carbonate on Pb/Sn surfaces exposed to tap and well water respectively containing silicate. The release of Pb can be explained satisfactorily on the basis of a scheme of reactions due to galvanic corrosion. (author)

  7. Application of CO2 laser for electronic components soldering

    Science.gov (United States)

    Mascorro-Pantoja, J.; Soto-Bernal, J. J.; Nieto-Pérez, M.; Gonzalez-Mota, R.; Rosales-Candelas, I.

    2011-10-01

    Laser provides a high controllable and localized spot for soldering joint formation and this is a valuable tool in Sn/Pb Soldering process on electronic industry, in recent years, laser beam welding has become an emerging welding technique, the use of laser in welding area is a high efficiency method. A 60 Watts CO2 continuous laser was used on this study, during welding experimental results indicated the laser could significantly improve speed and weld quality. In this work, the welding interactions of CO2 laser with Sn/Pb wire have been investigated in details through varying the energy ratios of laser. And at the same time, the effect of distance from laser spot to material.

  8. Laser soldering of piezoelectric actuator with minimal thermal impact

    OpenAIRE

    Seigneur, Frank; Fournier, Yannick; Maeder, Thomas; Jacot, Jacques

    2007-01-01

    Mechanical and electrical connecting of piezoelectric actuator is often done using conductive glue. Its advantage is not to heat the piezoelectric actuator during connection. But there are many disadvantages to gluing; the main one is curing time. Welding is another alternative, but when done in an oven, the temperature needed for this operation might destroy the heat sensitive actuator. The method described in this paper is laser soldering of piezoelectric actuator. The piezo actuator is mec...

  9. Comparative Tensile Strengths of Non-Precious Dental Alloy Solders.

    Science.gov (United States)

    1981-12-01

    thesis committee. My gratitude is extended to Dr. Charles Swoope and the Education and Research Foundation of Prosthodontics , Seattle, Washington, for...Most casting and soldering techniques used today in dentistry are those which were developed specifically for dental gold alloys. The newer , non...investment; this procedure yielded a more accurate finished casting. III. MATERIALS AND METHODS Dental materials research is carried out primarily to

  10. Trend Inspection Station for Printed Circuit Board Solder Joints.

    Science.gov (United States)

    1979-04-07

    the aid of CIRCON Corp. of Santa Barbara, CA, a leading supplier of micro-video systems. The total system would feature display options as well as a...PCB thus making the TIS a full inspection station for all solder joints. Battelle has used the CIRCON Corporation, a leader in CCTV inspection, as a... CIRCON . Further, their color TV camera is the smallest currently on the market and would be the easiest physically to incorporate into the TIS. Therefore

  11. 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.

  12. The Wiedemann–Franz–Lorenz relation for lead-free solder and intermetallic materials

    International Nuclear Information System (INIS)

    Yao, Yao; Fry, Jared; Fine, Morris E.; Keer, Leon M.

    2013-01-01

    Lead-free solders are replacing lead-rich solders in the electronics industry. Due to the limitation of available experimental data for thermal conductivity of lead-free solder and intermetallic compound (IMC) materials, the Wiedemann–Franz–Lorenz (WFL) relation is presented in this paper as a possible solution to predict thermal conductivity with known electrical conductivity. The method is based upon the fact that heat and electrical transport both involve free electrons. The thermal and electrical conductivities of Cu, Ni, Sn and different Sn-rich lead-free solder and IMC materials are studied by employing the WFL relation. Generally, analysis of the experimental data shows that the WFL relation is obeyed in both solder alloy and IMC materials, especially matching close to the relation for Sn, with a positive deviation from the theoretical Lorenz number. Thus, with the available electrical conductivity data, the thermal conductivity of solder and IMC materials can be obtained based on the proper WFL relation, and vice versa. A coupled thermal–electrical three-dimensional finite element analysis is performed to study the behavior of lead-free solder/IMC interconnects. Solder and IMC material properties predicted using the WFL relation are adopted in the computational model. By applying the WFL relation, the number of experiments required to determine the material properties for different lead-free solder/IMC interconnects can be significantly reduced, which can lead to pronounced savings of time and cost

  13. 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.

  14. Study on the Reliability of Carbon Nanotube-Reinforced Sn-58Bi Lead-Free Solder Joints

    Science.gov (United States)

    Yang, Li; Liu, Haixiang; Zhang, Yaocheng; Yu, Huakuan

    2017-12-01

    The wettability, microstructure and mechanical properties of multi-walled carbon nanotube (CNT)-reinforced Sn-58Bi composite solder joints were investigated. The results indicate that the wettability of the Sn-58Bi solder is improved and the growth of interfacial intermetallic (IMC) compounds for solder joints is restrained by CNTs. The thickness of the IMC layers is decreased with increasing CNTs concentration. The microstructure of the Sn-58Bi composite solders is refined, the maximum tensile strength and shear strength are obtained by adding the optimum CNTs content about 0.01 wt.%. However, excessive content of CNTs addition can deteriorate the properties. The creep rupture life of Sn-58Bi solder joint and Sn-58Bi-0.01CNTs solder joint is decreased with increasing load, temperature and current density. The average creep rupture life of Sn-58Bi-0.01CNTs composite solder joint is 60% higher than that of the plain solder joint.

  15. Finite element analysis and neural network model for electronic hidden solder joint geometry prediction

    Science.gov (United States)

    Giron Palomares, Jose Benjamin Dolores; Hsieh, Sheng-Jen

    2010-05-01

    This paper investigates an active thermography approach to probing hidden solder joint geometry. Ten boards were fabricated with the same number of solder joints and amount of solder paste (0.061 g), but using three solder joint geometries (60°, 90°, and 120°). The 90° angle solder pin represented a normal joint, and the 60° and 120° angle pins represented abnormal solder joints. Each board was covered with another board that had three openings just big enough to allow the pin terminals to protrude. A semi-automated system was built to heat and then transfer each board set to a chamber where an infrared camera was used to scan the board as it was cooling down. Each board set underwent the heating, cooling, and scanning process for five trials. Two-thirds of the data set was used for model development and one-third for model evaluation. An artificial neural network (ANN) was constructed to predict abnormal joints given thermal data. Results suggest that solder joints with more surface area cool much faster than those with less surface area. A Finite Element Analysis (FEA) of the heating up and cooling down process consistently predicted solder geometry using the ANN with 86% accuracy. This approach can be used not only to inspect bad solder joints (i.e., low reliability) but also to mass screen for cold solder joints during BGA assembly, since the air gaps in cold solder joints may cause them to cool more slowly than normal joints.

  16. Conducta alimentaria y perfil glucémico en dos líneas de ratas con diabetes genética: eSS y eSMT.

    OpenAIRE

    Silvana Marisa Montenegro; María Cristina Tarrés; Juan Carlos Picena; Stella Maris Martínez

    2005-01-01

    Introducción. La alimentación puede agravar la diabetes de humanos y modelos animales. Entre ellos, la rata eSMT presenta un curso más exacerbado y mayor biomasa que la línea parental eSS. Objetivo. Estudiar la conducta alimentaria de ratas macho eSMT y eSS ante oferta ilimitada y bajo restricción alternada, analizando su incidencia sobre el peso y la glucemia. Materiales y métodos. Se registró el consumo ad libitum en etapas de crecimiento y mantenimiento. Un grupo de eSMT recibió durante 5 ...

  17. 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...

  18. Residual stress distribution of the soldered structure with Kovar alloy and Al2O3 ceramics

    Directory of Open Access Journals (Sweden)

    Qile Gao

    2017-03-01

    Full Text Available Residual stress distribution in soldered structure of Kovar alloy and Al2O3 ceramics was determined using XRD analyses. In order to measure the residual stress, position of the characteristic diffraction peak and stress constant were obtained using several versatile/advanced techniques after calibration. Residual stress of soldered structure was measured based on the diffraction patterns obtained for the distribution of residual stress in the soldered joint. Only diffraction peak at 149° for Kovar alloy and two diffraction peaks ranging from 140–170° for Al2O3 ceramics were found to be appropriate for the residual stress determination. It was also confirmed that for Al2O3 ceramics the XRD peak at 152° reflects the changes of stress more precisely than the one at 146°. The stress constant K of Kovar alloy and Al2O3 ceramics was found to be −197 MPa/° and −654 MPa/°, respectively. After soldering, the maximum residual stress of the soldered joint of both materials developed at 1 mm from the soldering seam, and the values within 3 mm from the soldering seam are generally significant. Thus, it is important to pay attention to the area of 3 mm from the soldering seam in practical application.

  19. 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...

  20. Method and apparatus for jetting, manufacturing and attaching uniform solder balls

    Science.gov (United States)

    Yost, F.G.; Frear, D.R.; Schmale, D.T.

    1999-01-05

    An apparatus and process are disclosed for jetting molten solder in the form of balls directly onto all the metallized interconnects lands for a ball grid array package in one step with no solder paste required. Molten solder is jetted out of a grid of holes using a piston attached to a piezoelectric crystal. When voltage is applied to the crystal it expands forcing the piston to extrude a desired volume of solder through holes in the aperture plate. When the voltage is decreased the piston reverses motion creating an instability in the molten solder at the aperture plate surface and thereby forming spherical solder balls that fall onto a metallized substrate. The molten solder balls land on the substrate and form a metallurgical bond with the metallized lands. The size of the solder balls is determined by a combination of the size of the holes in the aperture plate, the duration of the piston pulse, and the displacement of the piston. The layout of the balls is dictated by the location of the hooks in the grid. Changes in ball size and layout can be easily accomplished by changing the grid plate. This invention also allows simple preparation of uniform balls for subsequent supply to BGA users. 7 figs.

  1. Dural reconstruction by fascia using a temperature-controlled CO2 laser soldering system

    Science.gov (United States)

    Forer, Boaz; Vasilyev, Tamar; Brosh, Tamar; Kariv, Naam; Gil, Ziv; Fliss, Dan M.; Katzir, Abraham

    2005-04-01

    Conventional methods for dura repair are normally based on sutures or stitches. These methods have several disadvantages: (1) The dura is often brittle, and the standard procedures are difficult and time consuming. (2) The seal is leaky. (3) The introduction of a foreign body (e.g. sutures) may cause an inflammatory response. In order to overcome these difficulties we used a temperature controlled fiber optic based CO2 laser soldering system. In a set of in vitro experiments we generated a hole of diameter 10 mm in the dura of a pig corpse, covered the hole with a segment of fascia, and soldered the fascia to the edges of the hole, using 47% bovine albumin as a solder. The soldering was carried out spot by spot, and each spot was heated to 65° C for 3-6 seconds. The soldered dura was removed and the burst pressure of the soldered patch was measured. The average value for microscopic muscular side soldering was 194 mm Hg. This is much higher than the maximal physiological pressure of the CSF fluid in the brain, which is 15 mm Hg. In a set of in vivo experiments, fascia patches were soldered on holes in five farm pigs. The long term results of these experiments were very promising. In conclusion, we have developed an advanced technique for dural reconstruction, which will find important clinical applications.

  2. Wettability study of lead free solder paste and its effect towards multiple reflow

    Directory of Open Access Journals (Sweden)

    Idris Siti Rabiatull Aisha

    2016-01-01

    Full Text Available Nowadays, wafer bumping using solder paste has come into focus as it provides a low cost method. However, since the industries are moving towards lead-free electronic packaging, a new type of no-clean flux was produced specifically for lead-free solder paste. Therefore, this study is used to evaluate the wettability of two different types of no-clean flux onto copper substrate. Besides, its effect towards multiple reflow was also studied. Reflow soldering was conducted for both types of solder paste that contained different type of no-clean flux for up to double reflow. Two different reflow profile was used. The results showed that the Flux A exhibit better soldering performance after first and second reflow soldering. In addition, type of intermetallic compound (IMC found after first reflow remain the same even after second reflow which was Cu-Sn based. This is shows that Flux A manage to control the diffusion process which will finally leads to a better solder joint performance. Nevertheless, mechanical testing should be carried out in order to evaluate the solder joint strength.

  3. Science Education in Nigeria: An Examination of People's Perceptions about Female Participation in Science, Mathematics and Technology

    Science.gov (United States)

    Ogunjuyigbe, Peter O.; Ojofeitimi, Ebenezer O.; Akinlo, Ambrose

    2006-10-01

    The paper brings to focus people's perception about female involvement in science, mathematics and technology (SMT). Data for the study were obtained from a survey conducted in March, 2005 in two Local Government Areas of Osun state, Southwest Nigeria. The paper reveals that: (i) about 57% of household heads, 45.6% of mothers and 57.6% of the children are of the opinion that both boys and girls are given equal right to SMT education (ii) social forces play an important role in determining people's attitude to SMT (iii) though, parents and stakeholders perceptions about girls' participation in some professions is changing, however, socio-cultural and economic factors still determine which sex to encourage to read SMT.

  4. 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.

  5. 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.

  6. 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.

  7. 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.)

  8. Nanospot soldering polystyrene nanoparticles with an optical fiber probe laser irradiating a metallic AFM probe based on the near-field enhancement effect.

    Science.gov (United States)

    Cui, Jianlei; Yang, Lijun; Wang, Yang; Mei, Xuesong; Wang, Wenjun; Hou, Chaojian

    2015-02-04

    With the development of nanoscience and nanotechnology for the bottom-up nanofabrication of nanostructures formed from polystyrene nanoparticles, joining technology is an essential step in the manufacturing and assembly of nanodevices and nanostructures in order to provide mechanical integration and connection. To study the nanospot welding of polystyrene nanoparticles, we propose a new nanospot-soldering method using the near-field enhancement effect of a metallic atomic force microscope (AFM) probe tip that is irradiated by an optical fiber probe laser. On the basis of our theoretical analysis of the near-field enhancement effect, we set up an experimental system for nanospot soldering; this approach is carried out by using an optical fiber probe laser to irradiate the AFM probe tip to sinter the nanoparticles, providing a promising technical approach for the application of nanosoldering in nanoscience and nanotechnology.

  9. Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Bismarck L., E-mail: bismarck_luiz@yahoo.com.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, 13083-860 Campinas, SP (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil)

    2016-04-15

    Low temperature soldering technology encompasses Sn–Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 °C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi–Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn–Bi–(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn–Bi–(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the microstructural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn–Bi–Cu and Sn–Bi–Ag alloys examined. - Highlights: • Dendritic growth prevailed for the ternary Sn–Bi–Cu and Sn–Bi–Ag solder alloys. • Bi precipitates within Sn-rich dendrites were shown to be unevenly distributed. • Morphology and preferential region for the Ag{sub 3}Sn growth depend on Ag

  10. FEM simulation of the size and constraining effect in lead free solder joints

    Directory of Open Access Journals (Sweden)

    Lederer M.

    2012-06-01

    Full Text Available Due to the ongoing miniaturization in microelectronics, the influence of dimensional constraining effects on the strength of solder joints becomes increasingly important. Detailed investigations show a strong dependence of tensile strength and ductility on solder geometry. This paper focuses on FEM simulations of the thickness effect of Sn-3.5Ag solder gaps under tensile load. Solder joints and copper base material are simulated with an elasto-plastic material model in the framework of von Mises plasticity. Within the solder material a pronounced triaxiality of stress is observed. In consequence, the von Mises stress inside the solder material is considerably smaller than the longitudinal stress along the tensile axis. This leads to increased tensile strength of thin solder joints. However, the increase of strength also depends on the yield stress of the copper base material. The FEM simulations were compared with experimental results of tensile tests and satisfactory coincidence was found. The remaining deviation between experiment and simulation is explained by pressure dependency of the flow stress. In conclusion, a new pressure dependent plasticity model is suggested.

  11. Characterization of the shear test method with low melting point In-48Sn solder joints

    International Nuclear Information System (INIS)

    Kim, Jong-Woong; Jung, Seung-Boo

    2005-01-01

    The ball shear tests were investigated in terms of effects of test parameters, i.e. shear height and shear speed, with an experimental and non-linear finite element analysis for evaluating the solder joint integrity of area array packages. A representative low melting point solder, In-48Sn, was examined in this work. The substrate was a common solder mask defined (SMD) type with solder bond pad openings of 460 μm in diameter. The microstructural investigations were carried out using scanning electron microscopy (SEM), and the intermetallic compounds (IMCs) were identified with energy dispersive spectrometer (EDS) and electron probe micro analyzer (EPMA). Shear tests were conducted with the two varying test parameters. It could be observed that increasing shear height, at fixed shear speed, has the effect of decreasing shear force, while the shear force increased with increasing shear speed at fixed shear height. Too high shear height could cause some bad effects on the test results such as unexpected high standard deviation values or shear tip sliding from the solder ball surface. The low shear height conditions were favorable for screening the type of brittle interfacial fractures or the degraded layers in the interfaces. The sensitivity of shear speed in In-48Sn solder is largely higher than those of Sn-based solders

  12. Corrosion reliability of electronics: the influence of solder temperature on the decomposition of flux activators

    DEFF Research Database (Denmark)

    Piotrowska, Kamila; Conseil, Helene; Jellesen, Morten Stendahl

    2014-01-01

    This manuscript gives a brief overview on the studies of thermal decomposition of solder flux systems commonly used in the electronic industry. Changes in chemical composition and structural changes of the flux components have been investigated as a function of temperature. Six weak organic acids......, serving as flux activators, have been studied. Additionally, eleven industrially used solder flux systems have been investigated towards their thermal decomposition pattern. The results show the formation of additional species at high soldering temperatures, some having more aggressive nature than...

  13. COST531 project: Study of the advanced materials for lead free soldering

    Directory of Open Access Journals (Sweden)

    Kroupa A.

    2007-01-01

    Full Text Available The COST 531 [1] project runt in the years 2002-2007, and dealt with the materials suitable for lead-free soldering. The main aim was to increase the basic knowledge on possible alloy systems that were used or planned to be used as lead-free solder materials and offer scientific information about these materials in order to replace the currently used lead-containing solders. The databases of materials and thermodynamic properties are one of the expected results and the basic features and properties of the thermodynamic database, allowing to model phase diagrams in multicomponent systems, are described in following paper.

  14. Effects of Solder Volume and Reflow Conditions on Self-Alignment Accuracy for Fan-Out Package Applications

    Science.gov (United States)

    Park, Hwan-Pil; Seo, Gwancheol; Kim, Sungchul; Kim, Young-Ho

    2018-01-01

    The effects of solder volume and reaction time between molten solder and a metal pad at the peak temperature of reflow on the self-alignment effect have been investigated in flip chip bonding. A glass die with two different pad designs and a flame retardant-4 (FR-4) organic substrate were used. Sn-3.0Ag-0.5Cu and Sn-3.5Ag solders were formed on Cu-organic solderability preservation (Cu-OSP) and electroless nickel electroless palladium immersion gold (ENEPIG) pads on FR-4 substrates using the stencil printing method. To assess the effect of solder volume, the thickness and opening size of the stencil mask were controlled. Reflow experiments were performed at 250°C with wetting times of 40 s, 55 s, 65 s, and 75 s. After flip chip reflow soldering, the bonding areas were cross-sectioned to inspect the shape of the interconnected solder using scanning electron microscopy. The results revealed that using an insufficient solder volume on the pad was responsible for die shifts larger than 1 μm, while a sufficient solder volume on the pad and a stable solder joint shape could ensure misalignment less than 1 μm. The Sn-3.0Ag-0.5Cu solder showed a lower die shift value than the Sn-3.5Ag solder because the Sn-3.0Ag-0.5Cu solder has stronger surface tension than the Sn-3.5Ag solder. Using a longer wetting time between the solder and the pad at the peak temperature also improved the die shift value because the increased reaction time changed the interconnected solder shape between the die and substrate from concave to convex, moving the die to a more accurate position. Furthermore, the restoring forces on die self-alignment influenced the die shift value. A stronger solder surface tension and a larger volume of solder on the pad produced stronger restoring forces for die self-alignment, thereby improving the die shift value.

  15. Influence of Zn additions on the interfacial reaction and microstructure of Sn37Pb/Cu solder joints

    Science.gov (United States)

    Qiu, Yu; Hu, Xiaowu; Li, Yulong; Jiang, Xiongxin

    2017-10-01

    The effects of Zn (5 and 10 wt%) additions into Sn37Pb solder and isothermal solid state aging on the interfacial reactions between Sn37Pb- xZn solders and Cu substrates were investigated in this study. It was found that the addition of Zn changed the types and morphologies of interfacial IMC layers during reflowing and thereafter under aging condition. During reflowing, the planar-type Cu5Zn8 compound was the interfacial IMC for Sn37Pb- xZn (5 and 10 wt%) solder, while the scallop-type Cu6Sn5 was the interfacial IMC for Sn37Pb solder. After aging, the final interfacial structure for Sn37Pb-5Zn solder was solder/Cu5Zn8/Cu6(Sn,Zn)5/Cu, while solder/Cu6Sn5/Cu3Sn/Cu for Sn37Pb solder and solder/Cu5Zn8/Cu for Sn37Pb-10Zn solder, respectively. The Kirkendall voids disappeared with Zn addition into Sn37Pb solder. For the Sn37Pb-5Zn/Cu solder joint, the thickness of Cu6(Sn,Zn)5 layer increased, while the thickness of Cu5Zn8 layer decreased with aging time extended to 360 h due to the decomposition of the Cu5Zn8 IMC layer by diffusing Cu and Zn atoms into nether IMC layer, combining Sn atoms diffused from solder matrix to form Cu6(Sn,Zn)5 IMCs. Furthermore, the growth of Cu6Sn5 and Cu3Sn layers for Sn37Pb/Cu solder joint and the total IMC layer at the interface of Sn37Pb- xZn ( x = 0, 5, and 10 wt%) solder with Cu substrate followed the diffusion control mechanism. Compared to the Sn37Pb-5Zn/Cu solder joint, higher Zn concentration depressed the growth of Cu5Zn8 layer for Sn37Pb-10Zn solder. In the end, refining effect on IMC grains was found by the addition of Zn into Sn37Pb solder and the 10 wt% Zn-doping significantly refined the interfacial IMC grains.

  16. 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

  17. 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.

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

    DEFF Research Database (Denmark)

    Li, Feng; Verdingovas, Vadimas; Medgyes, Balint

    2017-01-01

    The present work investigated the corrosion reliability of Sn-Ag-Cu based five lead-free solder alloys. The corrosion and electrochemical migration (ECM) susceptibility study of the solder alloys has been carried out by water droplet (WD) tests on pure alloy ingot samples, and by accelerated....... The galvanic corrosion was found between cathodically active Bi phase and anodic (Sn, Sb) solid solution in InnoLot alloy, while the Ag3Sn phase was cathodically active in the other four alloys. The paper theoretically illustrated the reason for the differences in corrosion reliability in the five alloys based...... 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...

  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. Report on an Assessment of the Application of EPP Results from the Strain Limit Evaluation Procedure to the Prediction of Cyclic Life Based on the SMT Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, R. I. [R. I. Jetter Consulting, Pebble Beach, CA (United States); Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The goal of the proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology is to incorporate an SMT data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. This methodology should minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed methodology and to verify the applicability of the code rules, analytical studies and evaluation of thermomechanical test results continued in FY17. This report presents the results of those studies. An EPP strain limits methodology assessment was based on recent two-bar thermal ratcheting test results on 316H stainless steel in the temperature range of 405 to 7050C. Strain range predictions from the EPP evaluation of the two-bar tests were also evaluated and compared with the experimental results. The role of sustained primary loading on cyclic life was assessed using the results of pressurized SMT data from tests on Alloy 617 at 9500C. A viscoplastic material model was used in an analytic simulation of two-bar tests to compare with EPP strain limits assessments using isochronous stress strain curves that are consistent with the viscoplastic material model. A finite element model of a prior 304H stainless steel Oak Ridge National Laboratory (ORNL) nozzle-to-sphere test was developed and used for an EPP strain limits and creep-fatigue code case damage evaluations. A theoretical treatment of a recurring issue with convergence criteria for plastic shakedown illustrated the role of computer machine precision in EPP calculations.

  1. Joint Lead-Free Solder Test Program for High Reliability Military and Space Applications

    Science.gov (United States)

    Brown, Christina

    2004-01-01

    Current and future space and defense systems face potential risks from the continued use of tin-lead solder, including: compliance with current environmental regulations, concerns about potential environmental legislation banning lead-containing products, reduced mission readiness, and component obsolescence with lead surface finishes. For example, the United States Environmental Protection Agency (USEPA) has lowered the Toxic Chemical Release reporting threshold for lead to 100 pounds. Overseas, the Waste Electrical and Electronic Equipment (WEEE) and the Restriction on Hazardous Substances (RoHS) Dicctives in Europe and similar mandates in Japan have instilled concern that a legislative body will prohibit the use of lead in aerospace/military electronics soldering. Any potential banning of lead compounds could reduce the supplier base and adversely affect the readiness of missions led by the National Aeronautics and Space Administration (NASA) and the U.S. Department of Defense (DoD). Before considering lead-free electronics for system upgrades or future designs, however, it is important for the DoD and NASA to know whether lead-free solders can meet their systems' requirements. No single lead-free solder is likely to qualify for all defense and space applications. Therefore, it is important to validate alternative solders for discrete applications. As a result of the need for comprehensive test data on the reliability of lead-free solders, a partnership was formed between the DoD, NASA, and several original equipment manufactures (OEMs) to conduct solder-joint reliability (laboratory) testing of three lead-free solder alloys on newly manufactured and reworked circuit cards to generate performance data for high-reliability (IPC Class 3) applications.

  2. 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.

  3. 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.

  4. MNiBLoS: A SMT-based Solver for Continuous t-norm Based Logics and Some of their Modal Expansions

    Czech Academy of Sciences Publication Activity Database

    Vidal, Amanda

    2016-01-01

    Roč. 372, 1 December (2016), s. 709-730 ISSN 0020-0255 R&D Project s: GA ČR(CZ) GF15-34650L Grant - others:Austrian Science Fund(AT) I1897-N25; EdeTRI:TIN2012-39348-C02-01(ES) MINECO project ; CSIC Intramural Project (ES) 201450E045 Institutional support: RVO:67985807 Keywords : fuzzy logics * modal logics * automated reasoning * continuous t-norms * SMT * infinitely valued logics Subject RIV: BA - General Mathematics Impact factor: 4.832, year: 2016

  5. 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.

  6. 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.

  7. 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.

  8. Inductive Soldering of the Junctions of the Main Superconducting Busbars of the LHC

    CERN Document Server

    Jacquemod, A; Schauf, F; Skoczen, Blazej; Tock, J P

    2004-01-01

    The Large Hadron Collider (LHC) is the next world-facility for the high energy physics community, presently under construction at CERN, Geneva. The LHC will bring into collisions intense beams of protons and ions. The main components of the LHC are the twin-aperture high-field superconducting cryomagnets that will be installed in the existing 26.7-km long tunnel. They are powered in series by superconducting Nb-Ti cables. Along the machine, about 60 000 joints between superconducting cables must be realised in-situ during the installation. Ten thousands of them, rated at 13 000 A, are involved in the powering scheme of the main dipoles and quadrupoles. To meet the requirements of the cryogenic budget, an electrical resistance at operating temperature (1.9 K) lower than 0.6 nW has to be achieved. The induction soldering technology was selected for this purpose. After a brief introduction to the LHC project, the constraints and requirements are listed. Then, the applied solution is detailed. The splices of the ...

  9. Low-stress soldering technique used to assemble an optical system for aerospace missions

    Science.gov (United States)

    Ribes-Pleguezuelo, P.; Koechlin, C.; Burkhardt, T.; Hornaff, M.; Kamm, A.; Gramens, S.; Beckert, E.; Fiault, G.; Eberhardt, R.; Tünnermann, A.

    2017-09-01

    A high-precision opto-mechanical breadboard for a lens mount has been assembled by means of a laserbased soldering process called Solderjet Bumping; which thanks to its localized and minimized input of thermal energy, is well suited for the joining of optical components made of fragile and brittle materials such as glasses. An optical element made of a silica lens and a titanium barrel has been studied to replicate the lens mounts of the afocal beam expander used in the LIDAR instrument (ATLID) of the ESA EarthCare Mission, whose aim is to monitor molecular and particle-based back-scattering in order to analyze atmosphere composition. Finally, a beam expander optical element breadboard with a silica lens and a titanium barrel was assembled using the Solderjet Bumping technology with Sn96.5Ag3Cu0.5 SAC305 alloy resulting in a low residual stress (<1 MPa) on the joining areas, a low light-depolarization (<0.2 %) and low distortion (wave-front error measurement < 5 nm rms) on the assemblies. The devices also successfully passed humidity, thermal-vacuum, vibration, and shock tests with conditions similar to the ones expected for the ESA EarthCare mission and without altering their optical performances.

  10. Comparative study on Virtual Reality Training (VRT over Sensory Motor Training (SMT in Unilateral Chronic Osteoarthritis – A Randomized Control Trial

    Directory of Open Access Journals (Sweden)

    Fathy Abdelazim Awwad Elshazly

    2016-08-01

    Full Text Available Osteoarthritis is a common rheumatologic disease. Several non operative interventions have been described for the treatment. But the available evidences of comparing the effectiveness of Virtual reality training over sensory motor training are very few. So, the purpose of this study is to compare the effectiveness of Virtual reality training over sensory motor training in the treatment of Osteoarthritis. 60 subjects who fulfilled the inclusion and exclusion criteria were divided into three Groups (1, 2 & 3 with randomized sampling method. Group 1 treated with Virtual reality training (VRT, Group 2 treated with sensory motor training (SMT and Group 3 (control treated with conventional exercise training (CET. The duration of the treatment was three times per week for 8 weeks in all the three groups. Subjects were assessed at baseline, at 4th and 8th week. Pain Intensity by Visual Analog scale (VAS, Joint Proprioception by Perception Sense, Functional Disability by WOMAC Score, and Quality of Life by HRQOL score were measured. A statistically significant (p ≤ 0.05 difference between all the 3 groups were noted at the period of 8 week for pain intensity, joint proprioception, functional disability and quality of life. Group-1 treated with (VRT shows more significant improvement in all parameters compared with Group-2 (SMT and Group-3 (CET. In conclusion, the addition of virtual reality training to conventional training exercises could improve pain and proprioception which subsequently improve the functional level and quality of life of OA patients

  11. Effect of Gap Distance on Tensile Strength of Preceramic Base Metal Solder Joints

    Directory of Open Access Journals (Sweden)

    Farnaz Fattahi

    2011-09-01

    Full Text Available Background and aims. 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. Materials and methods. 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. Results. 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 significant at a significance level of 0.05. Conclusion. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

  12. Microstructure, mechanical performance and corrosion properties of base metal solder joints

    Directory of Open Access Journals (Sweden)

    Sujesh Machha

    2011-01-01

    Full Text Available Context: Alloys have been considered to be of paramount importance in the field of prosthodontics. Long span prosthesis may often require joining of one or more individual castings to obtain better fit, occlusal harmony and esthetics in comparison to one-piece casting. Aim: This study was undertaken to evaluate the mechanical properties of base metal alloys joined by two different techniques, namely, gas oxygen torch soldering and laser fusion, compared to a one-piece casting. Mechanical properties evaluated were tensile strength, percentage of elongation and hardness of the solder joint. In addition, corrosion properties and scanning electron microscopic appearance of the joints were also evaluated. Materials and Methods: The samples were prepared according to American Society for Testing Materials specifications (ASTM, E8. Specimens were made with self-cure acrylic and then invested in phosphate-bonded investment material. Casting was done in induction casting machine. Thirty specimens were thus prepared for each group and compared with 30 specimens of the one-piece casting group. Statistical Analysis Used: SPSS software (version 10.0, Chicago, IL, USA was used for statistical analysis. ANOVA and Benferroni post hoc tests were done for multiple comparisons between the groups and within the groups for mean difference and standard error. Results: Results showed that tensile strength of the one-piece casting was higher than laser fused and gas oxygen torch soldered joints. Laser fused joints exhibited higher hardness values compared to that of gas oxygen torch soldered joints. Scanning electron microscopic examination revealed greater porosity in the gas oxygen torch soldered joints. This contributed to the reduction in the strength of the joint. Gas oxygen torch soldered joints showed less corrosion resistance when compared to laser fused joints and one-piece casting. Conclusion: Laser fusion, which is a recent introduction to the field of

  13. 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.

  14. Electrical Resistance of the Solder Connections for the Consolidation of the LHC Main Interconnection Splices

    CERN Document Server

    Lutum, R; Scheuerlein, C

    2013-01-01

    For the consolidation of the LHC 13 kA main interconnection splices, shunts will be soldered onto each of the 10170 splices. The solder alloy selected for this purpose is Sn60Pb40. In this context the electrical resistance of shunt to busbar lap splices has been measured in the temperature range from RT to 20 K. A cryocooler set-up has been adapted such that a test current of 150 A could be injected for accurate resistance measurements in the low nΩ range. To study the influence of the solder bulk resistivity on the overall splice resistance, connections produced with Sn96Ag4 and Sn77.2In20Ag2.8 have been studied as well. The influence of the Sn60Pb40 solder resistance is negligible when measuring the splice resistance in a longitudinal configuration over a length of 6 cm. In a transverse measurement configuration the splice resistance is significantly influenced by the solder. The connections prepared with Sn77.2In20Ag2.8 show significantly higher resistance values, as expected from the relatively high sol...

  15. Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

    Science.gov (United States)

    Erdogan, Ayse Tuygun; Nalbantgil, Didem; Ulkur, Feyza; Sahin, Fikrettin

    2015-07-01

    To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.

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

    Science.gov (United States)

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

    2009-11-01

    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.

  17. 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.

  18. The influence of heat treatment on properties of lead-free solders

    Directory of Open Access Journals (Sweden)

    Lýdia Trnková Rízeková

    2015-02-01

    Full Text Available The article is focused on the analysis of degradation of properties of two eutectic lead-free solders SnCu0.7 and SnAg3.5Cu0.7. The microstructures of the intermetallic compound (IMC layers at the copper substrate - solder interface were examined before and after heat treatment at 150°C for 50, 200, 500 and 1000 hours. The thickness of IMC layers of the Cu6Sn5 phase was growing with the increasing time of annealing and shown the typical scallops. For the heat treatment times of 200 hours and longer, the Cu3Sn IMC layers located near the Cu substrate were also observed. The experiments showed there is a link between the thickness of IMC layers and decrease of the shear strength of solder joints. In general, the joints made of the ternary solder showed higher shear strength before and after heat treatment in comparison to joints from solder SnCu0.7.

  19. Electrospun Poly(ɛ-Caprolactone) Scaffold for Suture-Free Solder-Mediated Laser-Assisted Vessel Repair

    NARCIS (Netherlands)

    Pabittei, Dara R.; Heger, Michal; Balm, Ron; Meijer, Han E. H.; de Mol, Bas; Beek, Johan F.

    2011-01-01

    Abstract Background and Objective: The addition of poly(lactic-co-glycolic) acid (PLGA) scaffolds to liquid solder-mediated laser-assisted vascular repair (sLAVR) has been shown to increase soldering strength significantly. Unfortunately, the fast degradation of PLGA is associated with adverse

  20. Investigating the heat transfer on the top side of inclined printed circuit boards during vapour phase soldering

    International Nuclear Information System (INIS)

    Illés, Balázs; Géczy, Attila

    2016-01-01

    Highlights: • Investigating the effect of inclination on heat transfer uniformity and intensity during VPS. • Even moderate inclination has high impact on the condensate layer and on the heat transfer. • Inclination under 1° has negative effect on temperature distribution of the soldered board. • Inclination from 1° to 10° improves heat transfer uniformity of vapour phase soldering. • Inclination can help to reduce soldering failures during vapour phase soldering. - Abstract: In this paper, heat transfer and condensate layer formation was investigated by numerical simulations on the top side of inclined printed circuit boards during vapour phase soldering. The phase change on the inclined surface and the transfer mechanisms in the condensate layer were embedded in a three-dimensional model. Steady-state and saturated vapour conditions were applied as boundary conditions in order to study the pure effect of the inclination. Due to the electronic component and circuit board structures during soldering only moderate inclination angles were studied between 0° and 10°. It was found that a moderate inclination of the printed circuit board has considerable effects on the formation of condensate layer and consequently on heat transfer. Compared to the default horizontal orientation of the board, the thickness differences of the condensate layer can be decreased with an optimised inclination of the printed circuit board. This effect homogenizes heat transfer during the process, enabling improved solder joint quality, with reduced overall soldering failure count.

  1. 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.

  2. Predicting the Drop Performance of Solder Joints by Evaluating the Elastic Strain Energy from High-Speed Ball Pull Tests

    Science.gov (United States)

    You, Taehoon; Kim, Yunsung; Kim, Jina; Lee, Jaehong; Jung, Byungwook; Moon, Jungtak; Choe, Heeman

    2009-03-01

    Despite being expensive and time consuming, board-level drop testing has been widely used to assess the drop or impact resistance of the solder joints in handheld microelectronic devices, such as cellphones and personal digital assistants (PDAs). In this study, a new test method, which is much simpler and quicker, is proposed. The method involves evaluating the elastic strain energy and relating it to the impact resistance of the solder joint by considering the Young’s modulus of the bulk solder and the fracture stress of the solder joint during a ball pull test at high strain rates. The results show that solder joints can be ranked in order of descending elastic strain energy as follows: Sn-37Pb, Sn-1Ag-0.5Cu, Sn-3Ag-0.5Cu, and Sn-4Ag-0.5Cu. This order is consistent with the actual drop performances of the samples.

  3. 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.

  4. Ultrasonic assisted fluxless flame soldering and brazing of aluminum alloys; Flussmittelfreies Flammloeten von Aluminiumlegierungen durch Ultraschallunterstuetzung

    Energy Technology Data Exchange (ETDEWEB)

    Bach, F.W. [FORTIS, ISOT GmbH, Witten (Germany); Moehwald, K.; Hollaender, U.; Stoll, P. [FORTIS, Hannover Univ., Hannover (Germany)

    2004-07-01

    Fluxless flame soldering and brazing of different pipe joints made of aluminium alloys can be realized by charging the joining zone with high power ultrasonic during the current process. The fundamental requirement for a successful ultrasonic assisted fluxless flame soldering or brazing is to couple the ultrasonic directly to the molten solder via a sonotrode. In order to guarantee defined acoustic conditions, constant temperature gradients in the sonotrode are required. This can be achieved by adapting a water cooling at the sonotrode. The acoustic energy which is applied to the joining zone causes the development of cavitations and ''micro-streams'' in the molten brazing filler metal. These effects ensure the occurrence of wetting and diffusion processes in the joining zone. (orig.)

  5. 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. 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...... 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....

  6. 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...... the equilibrium calculations by Scheil solidification simulations and optimization. A feasibility study has been carried out for the replacement of high-lead-containing solders with the focus on surface tension, natural radius of curvature, oxidation resistance, intermetallic compound formation, and environmental...

  7. 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.

  8. 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)

  9. Detection of small-size solder ball defects through heat conduction analysis

    Science.gov (United States)

    Zhou, Xiuyun; Chen, Yaqiu; Lu, Xiaochuan

    2018-02-01

    Aiming to solve the defect detection problem of a small-size solder ball in the high density chip, heat conduction analysis based on eddy current pulsed thermography is put forward to differentiate various defects. With establishing the 3D finite element model about induction heating, defects such as cracks and void can be distinguished by temperature difference resulting from heat conduction. Furthermore, the experiment of 0.4 mm-diameter solder balls with different defects is carried out to prove that crack and void solder can be distinguished. Three kinds of crack length on a gull-wing pin are selected, including 0.24 mm, 1.2 mm, and 2.16 mm, to verify that the small defect can be discriminated. Both the simulation study and experiment result show that the heat conduction analysis method is reliable and convenient.

  10. 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).

  11. 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.

  12. Effect of Ag on Sn–Cu and Sn–Zn lead free solders

    Directory of Open Access Journals (Sweden)

    Alam S.N.

    2015-06-01

    Full Text Available Lead and lead-containing compounds are considered as toxic substances due to their detrimental effect on the environment. Sn-based soldering systems, like Sn-Cu and Sn-Zn are considered as the most promising candidates to replace the eutectic Sn-Pb solder compared to other solders because of their low melting temperature and favorable properties. Eutectic Sn-0.7 wt.% Cu and near eutectic composition Sn-8 wt.% Zn solders have been considered here for study. For the Sn-Cu system, besides the eutectic Sn-0.7 wt.% Cu composition, Sn-1Cu and Sn-2Cu were studied. Three compositions containing Ag: Sn-2Ag-0.7Cu, Sn-2.5Ag-0.7Cu and Sn-4.5Ag-0.7Cu were also developed. Ag was added to the eutectic Sn-0.7 wt.% Cu composition in order to reduce the melting temperature of the eutectic alloy and to enhance the mechanical properties. For the Sn-Zn system, besides the Sn-8 wt.% Zn near eutectic composition, Sn-8Zn-0.05Ag, Sn-8Zn-0.1Ag and Sn-8Zn-0.2Ag solder alloys were developed. The structure and morphology of the solder alloys were analyzed using a scanning electron microscope (SEM, filed emission scanning electron microscope (FESEM, electron diffraction X-ray spectroscopy (EDX and X-ray diffraction (XRD. Thermal analysis of the alloys was also done using a differential scanning calorimeter (DSC. Trace additions of Ag have been found to significantly reduce the melting temperature of the Sn-0.7 wt.% Cu and Sn-8 wt.% Zn alloys.

  13. 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.

  14. 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

    One of the predominant factors for accelerated corrosion in electronics is the intrinsic contamination on Printed Circuit Board Assemblies (PCBAs) originating from the soldering process used for component mounting. However, the amount, distribution, and morphology of flux residue vary considerably...... 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...

  15. 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

  16. 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.

  17. 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....

  18. 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

    Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation...... the die-casting industry. As an example, the model is applied to several cases of high pressure die casting (HPDC) where A380 alloy parts are cast in the H13 steel die. The predicted locations of the higher strength of soldering appear in the "hot spot" areas of the die surface in agreement...

  19. An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

    2008-09-01

    The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in

  20. The failure models of Sn-based solder joints under coupling effects of electromigration and thermal cycling

    Science.gov (United States)

    Ma, Limin; Zuo, Yong; Liu, Sihan; Guo, Fu; Wang, Xitao

    2013-01-01

    Currently, the main concerns of Pb-free solder joints are focusing on electromigration (EM) and thermomechanical fatigue (TMF) problems. Many models have been established to understand the failure mechanisms of the joint under such single test conditions. Based on the fact that almost all microelectronic devices serve in combination conditions of fluctuated temperature and electric current stressing, the coupling effects of EM and TMF on evolution of microstructure and resistance of solder joint had been investigated. The failure models of binary SnBi alloy and ternary SnAgCu (SAC) solder under the coupling stressing were divided into four and three different stages, respectively. The failure mechanisms were dominant by the relationship of phase segregation, polarity effect, phase coarsening, and the coefficient of thermal expansion mismatch. Cracks tend to form and propagate along the interface between intermetallic compound layers and solder matrix in SAC solder. However, grain boundary was considered as the nucleation sites for microcracks in SnBi solder. High current density alleviates the deterioration of solder at the beginning stage of coupling stressing through Joule heating effect. An abrupt jump of resistance could be observed before the failure of the joint. The failure molds were determined by interactions of EM behaviors and TMF damages.

  1. COST531 project - study of the advanced materials for lead free soldering

    Czech Academy of Sciences Publication Activity Database

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

    2007-01-01

    Roč. 43, č. 2 (2007), s. 113-123 ISSN 1450-5339 R&D Projects: GA MŠk OC 531.002 Institutional research plan: CEZ:AV0Z20410507 Keywords : lead-free solders * thermodynamic database * Calphad method Subject RIV: BJ - Thermodynamics

  2. Longitudinal measurements of the cadmium burden of 'jig solderers' using IVNAA.

    Science.gov (United States)

    Perrin, B; Green, S; Morgan, W D

    1998-01-01

    The liver and kidney cadmium burdens of a population of 10 'jig solderers' were measured in 1983 and 1995 using similar IVNAA measuring systems. Cadmium exposure ceased in 1985. No significant variation in kidney content was observed. The mean body burden had fallen by 18%, due to a decrease of mean liver content of 35%.

  3. 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.

  4. Cross-border impacts of the restriction of hazardous substances: a perspective based on Japanese solders.

    Science.gov (United States)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2013-08-20

    Despite the relevance of the global economy, Regulatory Impact Assessments of the restriction of hazardous substances (RoHS) in the European Union (EU) are based only on domestic impacts. This paper explores the cross-border environmental impacts of the RoHS by focusing on the shifts to lead-free solders in Japan, which exports many electronics to the EU. The regulatory impacts are quantified by integrating a material flow analysis for metals constituting a solder with a scenario analysis with and without the RoHS. The results indicate that the EU regulation, the RoHS, has triggered shifts in Japan to lead-free solders, not only for electronics subject to this regulation, but for other products as well. We also find that the RoHS leads to a slow reduction in environmental emissions of the target, lead, but results in a rapid increase in the use of tin and silver in lead-free solders. This indicates the importance of assessing potential alternative substances, the use of which may increase as a result of adhering to the RoHS. The latter constitutes a negative impact because of recent concerns regarding resource criticality.

  5. The Development of the COST 531 Lead-Free Solders Thermodynamic Database

    Czech Academy of Sciences Publication Activity Database

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

    2007-01-01

    Roč. 59, č. 7 (2007), s. 20-25 ISSN 1047-4838 R&D Projects: GA MŠk OC 531.002; GA AV ČR KJB200410601 Institutional research plan: CEZ:AV0Z20410507 Keywords : lead-free solders * thermodynamic database Subject RIV: BJ - Thermodynamics Impact factor: 1.081, year: 2007

  6. 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

  7. 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

  8. Effects of Electromigration on the Creep and Thermal Fatigue Behavior of Sn58Bi Solder Joints

    Science.gov (United States)

    Zuo, Yong; Ma, Limin; Guo, Fu; Qiao, Lei; Shu, Yutian; Lee, Andree; Subramanian, K. N.

    2014-12-01

    Electromigration (EM), creep, and thermal fatigue (TF) are the most important aspects of the reliability of electronic solder joints, the failure mechanisms of which used to be investigated separately. However, current, mechanical loading, and temperature fluctuation usually co-exist under real service conditions, especially as the magnitude of current density is increasing with joint miniaturization. The importance of EM can no longer be simply ignored when analyzing the creep and TF behavior of a solder joint. The published literature reports that current density substantially changes creep rate, but the intrinsic mechanism is still unclear. Hence, the purpose of this study was to investigate the effects of EM on the creep and TF behavior of Sn58Bi solder joints by analyzing the evolution of electrical resistance and microstructure. The results indicated that EM shortens the lifetime of creep or TF of Sn58Bi solder joints. During creep, EM delays or suppresses the cracking and deforming process, so fracture occurs at the cathode interface. During TF, EM suppresses the cracking process and changes the interfacial structure.

  9. 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...

  10. 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.

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

    Indian Academy of Sciences (India)

    and could be related to the performance of the material in the real production environment. In the electronic manufacturing industry, the most popular method to deposit paste material. (solder paste and isotropic conductive adhesives) is known as stencil printing, as can be seen in figure 1. During the stencil printing process, ...

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

    Indian Academy of Sciences (India)

    Slippage due to wall depletion effect is well-known in rheological investigation. The aim of this study was to investigate the influence of the paste microstructure on slip formation for the paste materials (lead-free solder paste and isotropic conductive adhesives). The effect of different flow geometries, gap heights and surface ...

  13. Recrystallization Behavior in SAC305 and SAC305 + 3.0POSS Solder Joints Under Thermal Shock

    Science.gov (United States)

    Han, Jing; Gu, Penghao; Ma, Limin; Guo, Fu; Liu, Jianping

    2018-04-01

    Sn-3.0Ag-0.5Cu (SAC305) and SAC305 + 3.0 polyhedral oligomeric silsesquioxanes (POSS) ball grid array (BGA) assemblies have been prepared, observed, and subjected to thermal shock. The microstructure and grain orientation evolution of the solder joints located at the same position of the package were characterized by scanning electron microscopy and electron backscattering diffraction, respectively. The results showed that the microstructure of the solder joints was refined by addition of POSS particles. In addition, compared with the single-grained or tricrystal joints normally observed in SAC305 BGA solder joints, the frequency of single-grained as-reflowed SAC305 + 3.0POSS BGA joints was greatly reduced, and the solder joints were typically composed of multicrystals with orientations separated by high-angle grain boundaries. These multicrystal joints appear to be obtained by dominant tricrystals or double tricrystals with deviation of the preferred [110] and [1\\bar{1}0] growth directions of Sn dendrites in Sn-Ag-based solder alloys during solidification from the melt. After 928 thermal shock cycles, the SAC305 solder joint had large-area recrystallization and cracks in contrast to the SAC305 + 3.0POSS solder joint located at the same position of the package, indicating that addition of POSS to SAC305 solder joints may contribute to postponement of recrystallization and subsequent crack initiation and propagation along recrystallized grain boundaries by pinning grain boundaries and movement of dislocations. This finding also confirms the double tricrystal solidification twinning nucleation behavior in Pb-free solder joints.

  14. 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

  15. Microstructures and fatigue life of SnAgCu solder joints bearing Nano-Al particles in QFP devices

    Science.gov (United States)

    Zhang, Liang; Fan, Xi-ying; Guo, Yong-huan; He, Cheng-wen

    2014-05-01

    Microstructures and fatigue life of SnAgCu and SnAgCu bearing nano-Al particles in QFP (Quad flat package) devices were investigated, respectively. Results show that the addition of nano-Al particles into SnAgCu solder can refine the microstructures of matrix microstructure. Moreover, the nano-Al particles present in the solder matrix, act as obstacles which can create a back stress, resisting the motion of dislocations. In QFP device, it is found that the addition of nano-Al particles can increase the fatigue life by 32% compared with the SnAgCu solder joints during thermal cycling loading.

  16. CO2 laser nerve welding: optimal laser parameters and the use of solders in vitro.

    Science.gov (United States)

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

    1994-01-01

    To improve the welding strength, an in vitro study was performed to investigate the bonding strength of CO2 laser nerve welding (LNW), with and without the use of human albumin solution, dried albumin solution, egg white, fibrinogen solution, fibrin glue, and red blood cells as a solder. Fifteen different combinations of laser power (50, 100, and 150 mW) and pulse duration (0.1 to 3 s) were used with a spot size of 320 microns. The results have been compared to suture, fibrin glue, and laser-assisted nerve repair (LANR). The strongest welds (associated with whitening and caramelization of tissue) were produced at 100 mW with pulses of 1.0 s and at 50 mW with pulses of 3 s. The use of a dried albumin solution as a solder at 100 mW with pulses of 1 s increased the bonding strength 9-fold as compared to LNW (bonding strength 21.0 +/- 8.6 g and 2.4 +/- 0.9 g, respectively). However, positioning the nerves between cottons soaked in saline for 20 minutes resulted in a decrease of the bonding strength (9.8 +/- 4.5 g). The use of a 20% albumin solution and egg white, both at 50 mW with pulses of 3 s, resulted in a bonding strength of, respectively, 5.7 +/- 2.1 g and 7.7 +/- 2.4 g. Other solders did not increase the bonding strength in comparison to LNW. The substantial increase in bonding strength for some solders suggests that it is worthwhile to investigate the dehiscence rate and nerve regeneration of solder enhanced LNW in an in vivo study.

  17. Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

    Science.gov (United States)

    Tsui, Yeekin; Surrey, Elizabeth; Hampshire, Damian

    2016-07-01

    Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave the superconducting layer, cross the superconducting tape and pass into the solder that lies between the tape and the conductor that eventually provides one of the demountable surfaces. This paper considers the electrical and thermal properties of this essential component part of demountable high temperature superconducting (HTS) joints by considering the fabrication and properties of jointed HTSs consisting of a thin layer of solder (In52Sn48 or Pb38Sn62) sandwiched between two rare-earth-Ba2Cu3O7 (REBCO) second generation HTS coated conductors (CCs). The HTS joints are analysed using numerical modelling, critical current and resistivity measurements on the joints from 300 to 4.2 K in applied magnetic fields up to 12 T, as well as scanning electron microscopy studies. Our results show that the copper/silver layers significantly reduce the heating in the joints to less than a few hundred mK. When the REBCO alone is superconducting, the joint resistivity (R J) predominantly has two sources, the solder layer and an interfacial resistivity at the REBCO/silver interface (∼25 nΩ cm2) in the as-supplied CCs which together have a very weak magnetoresistance in fields up to 12 T. We achieved excellent reproducibility in the R J of the In52Sn48 soldered joints of better than 10% at temperatures below T c of the REBCO layer which can be compared to variations of more than two orders of magnitude in the literature. We also show that demountable joints in fusion energy magnets are viable and need only add a few percent to the total cryogenic cost for a fusion tokamak.

  18. 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.

  19. Low Temperature Flex-on-Flex Assembly Using Polyvinylidene Fluoride Nanofiber Incorporated Sn58Bi Solder Anisotropic Conductive Films and Vertical Ultrasonic Bonding

    Directory of Open Access Journals (Sweden)

    Tae-Wan Kim

    2013-01-01

    Full Text Available In this study, solder ball incorporated polyvinylidenefluoride (PVDF nanofiber was added into the ACF system to overcome short circuit issues of fine pitch flex-on-flex (FOF assembly. Also, in order to improve the thermal mismatch of the flexible substrate which can lead to electrode misalignment during the bonding process, low melting temperature Sn58Bi solder balls were used with vertical ultrasonic (U/S bonding method. When performing FOF assembly using PVDF nanofiber/Sn58Bi solder ACF and vertical ultrasonic bonding, PVDF nanofiber/Sn58Bi solder ACFs showed 34% higher solder capture rate on an electrode compared to conventional Ni ACFs and conventional Sn58Bi solder ACFs. Additionally, PVDF nanofiber/Sn58Bisolder ACFs showed 100% insulation between neighboring electrodes where conventional Ni ACFs and conventional Sn58Bi solder ACFs showed 75% and 87.5% insulation. Other electrical properties such as contact resistance and current handling capability as well as reliability test of PVDF nanofiber/Sn58Bi solder ACFs showed improved results compared to those of conventional Ni ACFs, which proves the formation of stable solder joint of PVDF nanofiber/Sn58Bi solder ACFs.

  20. THE EFFECT OF REFLOW ON WETTABILITY OF Sn 96.5 Ag 3 Cu 0.5 SOLDER

    Directory of Open Access Journals (Sweden)

    Zoltán Weltsch

    2012-12-01

    Full Text Available Surface conditions on Printed Circuit Board (PCB final finishes have an important impact on the wetting behavior with lead-free solder. The improvement of the 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 were 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 affecting the wetting properties is the amount of oxygen in the soldering atmosphere. Using the inert atmosphere is crucial in case of Pb-free solders, particularly after reflows.

  1. 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.

  2. 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...... cases, as the flux residue left on a printed circuit board assembly is a key factor compromising the corrosion reliability under humid conditions. This investigation focuses on the chemical degradation of three kinds of solder flux systems based on adipic, succinic, and glutaric acid as a function...... of temperature, thus simulating the soldering process. Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and Ion Chromatography were employed for decomposition and residue analysis. Aggressiveness of the residue was investigated using a pH indicator gel test and by acid value...

  3. Novel Ruggedized Packaging Technology for VCSELs

    Science.gov (United States)

    2017-03-01

    creates board-level solder interconnect at the wafer level, e liminating t he cost and parasitics as sociated with p ackages. O TDR technology enables...10.3125 is -12.6 dBm OMA. SERDES TOSA Wavelength/fiber dependant components LDD fiber plant ROSATIA-LA ROSA OTDR RX Pulse Gen MUX OTDR ASIC

  4. An ArsR/SmtB family member is involved in the regulation by arsenic of the arsenite oxidase operon in Thiomonas arsenitoxydans.

    Science.gov (United States)

    Moinier, Danielle; Slyemi, Djamila; Byrne, Deborah; Lignon, Sabrina; Lebrun, Régine; Talla, Emmanuel; Bonnefoy, Violaine

    2014-10-01

    The genetic organization of the aioBA operon, encoding the arsenite oxidase of the moderately acidophilic and facultative chemoautotrophic bacterium Thiomonas arsenitoxydans, is different from that of the aioBA operon in the other arsenite oxidizers, in that it encodes AioF, a metalloprotein belonging to the ArsR/SmtB family. AioF is stabilized by arsenite, arsenate, or antimonite but not molybdate. Arsenic is tightly attached to AioF, likely by cysteine residues. When loaded with arsenite or arsenate, AioF is able to bind specifically to the regulatory region of the aio operon at two distinct positions. In Thiomonas arsenitoxydans, the promoters of aioX and aioB are convergent, suggesting that transcriptional interference occurs. These results indicate that the regulation of the aioBA operon is more complex in Thiomonas arsenitoxydans than in the other aioBA containing arsenite oxidizers and that the arsenic binding protein AioF is involved in this regulation. On the basis of these data, a model to explain the tight control of aioBA expression by arsenic in Thiomonas arsenitoxydans is proposed. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  5. Electromigration Critical Product to Measure Effect of Underfill Material in Suppressing Bi Segregation in Sn-58Bi Solder

    Science.gov (United States)

    Zhao, Xu; Takaya, Satoshi; Muraoka, Mikio

    2017-08-01

    Recently, we detected length-dependent electromigration (EM) behavior in Sn-58Bi (SB) solder and revealed the existence of Bi back-flow, which retards EM-induced Bi segregation and is dependent on solder length. The cause of the back-flow is attributed to an oxide layer formed on the SB solder. At present, underfill (UF) material is commonly used in flip-chip packaging as filler between chip and substrate to surround solder bumps. In this study, we quantitatively investigated the effect of UF material as a passivation layer on EM in SB solder strips. EM tests on SB solder strips with length of 50 μm, 100 μm, and 150 μm were conducted simultaneously. Some samples were coated with commercial thermosetting epoxy UF material, which acted as a passivation layer on the Cu-SB-Cu interconnections. The value of the critical product for SB solder was estimated to be 38 A/cm to 43 A/cm at 353 K to 373 K without UF coating and 59 A/cm at 373 K with UF coating. The UF material acting as a passivation layer suppressed EM-induced Bi segregation and increased the threshold current density by 37% to 55%. However, at very high current density, this effect became very slight. In addition, Bi atoms can diffuse to the anode side through the Sn phase, hence addition of microelements to the Sn phase to form obstacles, such as intermetallic compounds, may retard Bi segregation in SB solder.

  6. 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.

  7. Influence of supply of heat to cobalt-chromium frameworks during soldering and subsequent hardening heat treatment of wrought clasps.

    Science.gov (United States)

    Eriksson, T; Sjögren, G; Bergman, M

    1983-01-01

    Retentive clasp arms of wrought gold alloy wire were soldered to frameworks made of three dental cobalt-chromium alloys. The clasps were then subjected to a conventional hardening heat treatment. Microstructure and hardness of the cobalt-chromium alloys were determined before and after these operations. The results reveal that the supply of heat during soldering and hardening heat treatment of the clasp does not influence the microstructure and hardness of the cobalt-chromium alloys.

  8. Thermal Fluid-Structure Interaction in the Effects of Pin-Through-Hole Diameter during Wave Soldering

    Directory of Open Access Journals (Sweden)

    M. S. Abdul Aziz

    2014-03-01

    Full Text Available An effective simulation approach is introduced in this paper to study the thermal fluid-structure interaction (thermal FSI on the effect of pin-through-hole (PTH diameter on the wave soldering zone. A 3D single PTH connector and a printed circuit board model were constructed to investigate the capillary flow behavior when passing through molten solder (63SnPb37. In the analysis, the fluid solver FLUENT was used to solve and track the molten solder advancement using the volume of fluid technique. The structural solver ABAQUS was used to examine the von Mises stress and displacement of the PTH connector in the wave soldering process. Both solvers were coupled by MpCCI software. The effects of six different diameter ratios (0.1 < d/D < 0.97 were studied through a simulation modeling. The use of ratio d/D = 0.2 yielded a balanced filling profile and low thermal stress. Results revealed that filling level, temperature, and displacement exhibited polynomial behavior to d/D. Stress of pin varied quadratically with the d/D. The predicted molten solder profile was validated by experimental results. The simulation results are expected to provide better visualization and understanding of the wave soldering process by considering the aspects of thermal FSI.

  9. Microstructural evolution and IMCs growth behavior of Sn-58Bi-0.25Mo solder joint during aging treatment

    Science.gov (United States)

    Yang, Li; Zhu, Lu; Zhang, Yaocheng; Zhou, Shiyuan; Xiong, Yifeng; Wu, Pengcheng

    2018-02-01

    The microstructural evolution and IMCs growth behavior of Sn-58Bi and Sn-58Bi-0.25Mo solder joints were investigated. The results showed that the microstructure is coarsened, the IMCs layer thickness is increased and the tensile strength of Sn-58Bi and Sn-58Bi-0.25Mo solder joints is decreased with increasing aging time and temperature. Aging temperature is the key factor that causes the excessive IMCs growth of the solder joint compared with aging time, and the activation energy of IMCs layer growth of Sn-58Bi and Sn-58Bi-0.25Mo solder joints is 48.94 kJ mol‑1 and 53.79 kJ mol‑1, respectively. During the aging treatment, the microstructure of Sn-58Bi solder joint is refined by adding Mo nanoparticles, and the appropriate IMCs layer thickness and improved mechanical properties are obtained by Sn-58Bi-0.25Mo solder joint.

  10. 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.

  11. 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.

  12. Relative effect of solder flux chemistry on the humidity related failures in electronics

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    was studied by quartz crystal microbalance, while corrosive effects were studied by leakage current and impedance measurements on standard test boards. The measurements were performed as a function of relative humidity (RH) in the range from 60 to ~99 per cent at 25°C. The corrosiveness of solder flux systems...... of printed circuit boards under humid conditions. Originality/value - The classification of solder flux systems according to IPC J-STD-004 standard does not specify the WOAs in the flux; however, ranking of the flux systems based on the hygroscopic property of activators would be useful information when...... selecting no-clean flux systems for electronics with applications in humid conditions....

  13. An Organic Metal/Silver Nanoparticle Finish on Copper for Efficient Passivation and Solderability Preservation

    Directory of Open Access Journals (Sweden)

    Wessling Bernhard

    2007-01-01

    Full Text Available AbstractFor the first time, a complex formed by polyaniline (in its organic metal form and silver has been deposited on copper in nanoparticulate form. When depositing on Cu pads of printed circuit boards it efficiently protects against oxidation and preserves its solderability. The deposited layer has a thickness of only nominally 50 nm, containing the Organic Metal (conductive polymer, polyaniline, and silver. With >90% (by volume, polyaniline (PAni is the major component of the deposited layer, Ag is present equivalent to a 4 nm thickness. The Pani–Ag complex is deposited on Cu in form of about 100 nm small particles. Morphology, electrochemical characteristics, anti-oxidation and solderability results are reported.

  14. 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.

  15. Surface tension and density of binary lead and lead-free Sn-based solders

    Science.gov (United States)

    Kaban, I.; Mhiaoui, S.; Hoyer, W.; Gasser, J.-G.

    2005-12-01

    The surface tension and density of the liquid Sn60Pb40, Sn90Pb10, Sn96.5Ag3.5 and Sn97Cu3 solder alloys (wt%) have been determined experimentally over a wide temperature interval. It is established that the surface tension of liquid Sn90Pb10 is about 7% higher than that of a traditional Sn60Pb40 solder and that the surface tension of Sn96.5Ag3.5 and Sn97Cu3 alloys is about 12% higher than that of Sn60Pb40. The analytical expressions for the temperature dependences of the surface tension and density are given.

  16. Formation mechanism of pillar-shaped intermetallic compounds dispersed lead-free solder joint

    Science.gov (United States)

    Nakata, Y.; Hashimoto, T.; Kurasawa, M.; Hayashi, Y.; Shohji, I.

    2017-10-01

    Large area joining between a substrate and a heat sink is desirable for high performance power modules. An intermetallic compounds (IMCs) pillar dispersed solder joint has been developed as a highly durable joint to achieve large area joining. The aim of this study is to clarify the generation and growth mechanism of the IMC pillar during soldering process. The structural characteristic of the IMC pillar was also examined by cross-sectional observation. The area ratio of the IMC pillars in the cross section of the joint increased with increasing the joining temperature. The shape of the IMC pillar became finer when the cooling rate was fast. In addition, the IMC pillar grew along the cooling direction.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Influence of active element Ti on interfacial reaction and soldering strength between Sn3.5Ag4Ti(Ce,Ga) alloy filler and Si substrate

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, L.X. [School of Electronic and Information Engineering, South China University of Technology, Wushan R.D., Tianhe District, Guangzhou 510641 (China); Li, G.Y., E-mail: phgyli@scut.edu.cn [School of Electronic and Information Engineering, South China University of Technology, Wushan R.D., Tianhe District, Guangzhou 510641 (China); Wang, X.Q. [China Electronic Product Reliability and Environmental Testing Research Institute, Dongguanzhuang R.D., Tianhe District, Guangzhou 510610 (China); Li, Z.L.; Wu, Z.Z. [School of Electronic and Information Engineering, South China University of Technology, Wushan R.D., Tianhe District, Guangzhou 510641 (China)

    2016-03-21

    The influence of titanium on the interfacial reaction and soldering strength between Sn3.5Ag4Ti(Ce,Ga) and silicon substrates has been studied. The microstructure, the distribution of the elements, and the new phases formed at the interface were investigated. It is observed that the Sn3.5Ag4Ti(Ce,Ga) solder can wet the silicon well under the agitation of external force. The titanium element could be found to obviously segregate at the silicon/solder interface by element mapping, and some discontinuous reaction products could be found at the silicon/solder interface by transmission electron microscopy (TEM). Theoretical analysis results suggest that there might be two soldering mechanisms coexisting in the soldering process, the chemical adsorption of Ti on the silicon surface and the interfacial reaction between Si substrate and Sn3.5Ag4Ti(Ce,Ga) solder. Both of them play important roles in realizing reliable bonding of silicon to silicon. The interfacial model between Si and Sn3.5Ag4Ti(Ce,Ga) active solder was established to explain the bonding mechanism. The shear strengths of the soldered silicon/silicon joints were measured and the effects of Ti on the bonding strength are discussed.

  2. 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...

  3. The influence of solder mask and hygroscopic flux residues on water layer formation on PCBA surface and corrosion reliability of electronics

    DEFF Research Database (Denmark)

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

    2017-01-01

    The presence of solder flux residue on the Printed Circuit Board Assembly (PCBA) surface compromises the corrosion reliability of electronics under humid conditions and can lead to degradation of the device’s lifetime. In this work, the effect of solder mask morphology and hygroscopic residues were...... studied towards assessment of their influence on the water film formation on the PCBA surface. The in-situ observations of water layer build-up was studied on the solder mask substrates as a function of surface finish and residue type (adipic and glutaric acids). The effect of solder flux residues...

  4. Conducta alimentaria y perfil glucémico en dos líneas de ratas con diabetes genética: eSS y eSMT.

    Directory of Open Access Journals (Sweden)

    Silvana Marisa Montenegro

    2005-12-01

    Full Text Available Introducción. La alimentación puede agravar la diabetes de humanos y modelos animales. Entre ellos, la rata eSMT presenta un curso más exacerbado y mayor biomasa que la línea parental eSS. Objetivo. Estudiar la conducta alimentaria de ratas macho eSMT y eSS ante oferta ilimitada y bajo restricción alternada, analizando su incidencia sobre el peso y la glucemia. Materiales y métodos. Se registró el consumo ad libitum en etapas de crecimiento y mantenimiento. Un grupo de eSMT recibió durante 5 semanas a partir del destete, una dieta restringida intermitente seguida de oferta ilimitada, y otro fue restringido hasta el año de edad, midiéndose el peso y el perfil glucémico en distintas edades. Resultados. Durante el crecimiento, eSMT aumentó de peso más que eSS con ingestas similares, y en la etapa de mantenimiento sustentó mayor biomasa con menor consumo. La restricción intermitente posterior al destete indujo un patrón de crecimiento más lento y menor peso adulto. A los 5 meses presentaron valores de G0 normales (85±12 mg/dl y los controles mostraron cifras alteradas (119±14 mg/dl. En los animales restringidos la posterior oferta ilimitada produjo glucemias de ayuno compatibles con diabetes (163±25 mg/dl y un incremento ponderado 75% superior a los alimentados ad libitum. Conclusión. La alternancia prolongada hambre-saciedad indujo en eSMT desaceleración de su metabolopatía mientras que la realimentación se asoció con incrementos superiores de peso y glucemia, atribuibles a un aumento de la eficiencia de conversión inducida por el ayuno. Estos resultados enfatizan la importancia de mejorar el conocimiento sobre las relaciones entre crecimiento, alimentación y diabetes.

  5. 86Y-DOTA0-d-Phe1-Tyr3-octreotide (SMT487) - a phase 1 clinical study: pharmacokinetics, biodistribution and renal protective effect of different regimens of amino acid co-infusion

    International Nuclear Information System (INIS)

    Jamar, Francois; Barone, Raffaella; Mathieu, Isabelle; Walrand, Stephan; Labar, Daniel; Carlier, Pascal; De Camps, Joelle; Pauwels, Stanislas; Schran, Horst; Chen, TianLing; Smith, M.Charles; Bouterfa, Hakim; Valkema, Roelf; Krenning, Eric P.; Kvols, Larry K.

    2003-01-01

    The pharmacokinetics and dosimetry of 86 Y-DOTA 0 -d-Phe 1 -Tyr 3 -octreotide ( 86 Y-SMT487) were evaluated in a phase I positron emission tomography (PET) study of 24 patients with somatostatin receptor-positive neuroendocrine tumours. The effect of amino acid (AA) co-infusion on renal and tumour uptake was assessed in a cross-over randomised setting. Five regimens were tested: no infusion, 4-h infusion of 120 g mixed AA (26.4 g l-lysine + l-arginine), 4 h l-lysine (50 g), 10 h 240 g mixed AA (52.8 g l-lysine + l-arginine) and 4 h Lys-Arg (25 g each). Comparisons were performed on an intra-patient basis. Infusions of AA started 0.5 h prior to injection of 86 Y-SMT487 and PET scans were obtained at 4, 24 and 48 h p.i. Absorbed doses to tissues were computed using the MIRD3 method. 86 Y-SMT487 displayed rapid plasma clearance and exclusive renal excretion; uptake was noted in kidneys, tumours, spleen and, to a lesser extent, liver. The 4-h mixed AA co-infusion significantly (P 86 Y-SMT487 renal uptake by a mean of 21%. This protective effect was significant on the dosimetry data (3.3±1.3 vs 4.4±1.0 mGy/MBq; P 90 Y-SMT487 (maximum allowed dose: MAD) that would result in a 23-Gy cut-off dose to kidneys was calculated for each study: MAD was higher with mixed AA co-infusion by a mean of 46% (10-114%, P<0.05 vs no infusion). In comparison with 4 h mixed AA, the MAD was higher by a mean of 23% (9-37%; P<0.05) with prolonged infusion and by a mean of 16% (2-28%; P<0.05) with Lys-Arg. We conclude that infusion of large amounts of AA reduces renal exposure during peptide-based radiotherapy and allows higher absorbed doses to tumours. The prolongation of the infusion from 4 to 10 h further enhances the protective effect on the kidneys. (orig.)

  6. Uniaxial tensile and shear deformation tests of gold–tin eutectic solder film

    Directory of Open Access Journals (Sweden)

    Takahiro Namazu, Hideki Takemoto, Hiroshi Fujita and Shozo Inoue

    2007-01-01

    Full Text Available This paper describes a novel experimental technique for measuring mechanical properties of gold-tin (Au–Sn eutectic solder film used for soldering package in microelectromechanical systems (MEMS. Dual-source DC magnetron sputtering was employed to deposit Au-20 weight % (wt% Sn film. The tensile test with in situ X-ray diffraction (XRD measurement evaluates the Young's modulus and Poisson's ratio at intermediate temperatures. The Young's modulus and Poisson's ratio at room temperature were found to be 51.3 GPa and 0.288, lower than bulk values. The Young's modulus decreased with increasing temperature, whereas the Poisson's ratio did not depend on temperature. The XRD tensile test also showed creep deformation behavior of Au–Sn film. We have developed a shear deformation test technique, which is performed by using Au–Sn film sandwiched by two single crystal silicon (Si cantilever structures, to characterize the shear properties of the film. The shear moduli obtained from the shear deformation tests ranged from 11.5 to 13.3 GPa, about 38% lower than those from the XRD tensile tests. The measured shear strength from 12 to 17 MPa exhibited a temperature dependency. Information about the tensile and shear characteristics would likely to be of great use in designing Au–Sn soldering packages for MEMS.

  7. Research of Interaction Between Zn Based Solders and Cu, Al Substrates

    Directory of Open Access Journals (Sweden)

    Prach Michal

    2014-06-01

    Full Text Available The paper deals with the study of interaction between Cu, Al substrates (purity 5N and ZnAl4, ZnAg6Al6 zinc solders for higher application temperatures. Soldering was performed with power ultrasound in the air without flux application at temperature 420 °C. Acting time of ultrasonic vibration was 3 s and ultrasound frequency was 40 kHz. Soldered joints were assessed by optical light microscopy and EDX microanalysis. Intermetallic layers (IM CuZn4 and Cu5Zn8 were formed at the Cu/ZnAl4 boundary. The βZn-αAl mechanical mixture was formed at the Al/ZnAl4 boundary. AgZn3 and Cu5Zn8 IM layers were formed at the Cu/ZnAg6Al6 boundary, and mechanical mixture of βZn-αAl and AgZn3 intermetallic mixture were formed at the boundary Al/ZnAg6Al6.

  8. The Influence of PV Module Materials and Design on Solder Joint Thermal Fatigue Durability

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah

    2016-11-01

    Finite element model (FEM) simulations have been performed to elucidate the effect of flat plate photovoltaic (PV) module materials and design on PbSn eutectic solder joint thermal fatigue durability. The statistical method of Latin Hypercube sampling was employed to investigate the sensitivity of simulated damage to each input variable. Variables of laminate material properties and their thicknesses were investigated. Using analysis of variance, we determined that the rate of solder fatigue was most sensitive to solder layer thickness, with copper ribbon and silicon thickness being the next two most sensitive variables. By simulating both accelerated thermal cycles (ATCs) and PV cell temperature histories through two characteristic days of service, we determined that the acceleration factor between the ATC and outdoor service was independent of the variables sampled in this study. This result implies that an ATC test will represent a similar time of outdoor exposure for a wide range of module designs. This is an encouraging result for the standard ATC that must be universally applied across all modules.

  9. A dislocation density based micromechanical constitutive model for Sn-Ag-Cu solder alloys

    Science.gov (United States)

    Liu, Lu; Yao, Yao; Zeng, Tao; Keer, Leon M.

    2017-10-01

    Based on the dislocation density hardening law, a micromechanical model considering the effects of precipitates is developed for Sn-Ag-Cu solder alloys. According to the microstructure of the Sn-3.0Ag-0.5Cu thin films, intermetallic compounds (IMCs) are assumed as sphere particles embedded in the polycrystalline β-Sn matrix. The mechanical behavior of polycrystalline β-Sn matrix is determined by the elastic-plastic self-consistent method. The existence of IMCs not only impedes the motion of dislocations but also increases the overall stiffness. Thus, a dislocation density based hardening law considering non-shearable precipitates is adopted locally for single β-Sn crystal, and the Mori-Tanaka scheme is applied to describe the overall viscoplastic behavior of solder alloys. The proposed model is incorporated into finite element analysis and the corresponding numerical implementation method is presented. The model can describe the mechanical behavior of Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu alloys under high strain rates at a wide range of temperatures. Furthermore, the overall Young’s modulus changes due to different contents of IMCs is predicted and compared with experimental data. Results show that the proposed model can describe both elastic and inelastic behavior of solder alloys with reasonable accuracy.

  10. 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...

  11. Recrystallization and Precipitate Coarsening in Pb-Free Solder Joints During Thermomechanical Fatigue

    Science.gov (United States)

    Yin, Liang; Wentlent, Luke; Yang, Linlin; Arfaei, Babak; Oasaimeh, Awni; Borgesen, Peter

    2012-02-01

    The recrystallization of β-Sn profoundly affects deformation and failure of Sn-Ag-Cu solder joints in thermomechanical fatigue (TMF) testing. The numerous grain boundaries of recrystallized β-Sn enable grain boundary sliding, which is absent in as-solidified solder joints. Fatigue cracks initiate at, and propagate along, recrystallized grain boundaries, eventually leading to intergranular fracture. The recrystallization behavior of Sn-Ag-Cu solder joints was examined in three different TMF conditions for five different ball grid array component designs. Based on the experimental observations, a TMF damage accumulation model is proposed: (1) strain-enhanced coarsening of secondary precipitates of Ag3Sn and Cu6Sn5 starts at joint corners, eventually allowing recrystallization of the Sn grain there as well; (2) coarsening and recrystallization continue to develop into the interior of the joints, while fatigue crack growth lags behind; (3) fatigue cracks finally progress through the recrystallized region. Independent of the TMF condition, the recrystallization appeared to be essentially complete after somewhat less than 50% of the characteristic life, while it took another 50% to 75% of the lifetime for a fatigue crack to propagate through the recrystallized region.

  12. 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...

  13. Synthesis of composite gold/tin-oxide nanoparticles by nano-soldering

    International Nuclear Information System (INIS)

    Bajaj, Geetika; Soni, R. K.

    2010-01-01

    Composite Au-SnO 2 nanoparticles (NPs) are synthesized by nano-soldering of pure Au and SnO 2 NPs. The multi-step process involves synthesis of pure Au and SnO 2 NPs separately by nanosecond pulse laser ablation of pure gold and pure tin targets in deionized water and post-ablation laser heating of mixed solution of Au colloidal and SnO 2 colloidal to form nanocomposite. Transmission Electron Microscopy (TEM) and High-Resolution Transmission Electron Microscopy (HRTEM) were used to study the effect of laser irradiation time on morphology of the composite Au-SnO 2 NPs. The spherical particles of 4 nm mean size were obtained for 5 min of post-laser heating. Increased mean size and elongated particles were observed on further laser heating. UV-vis spectra of Au-SnO 2 nanocomposites show red shift in the plasmon resonance absorption peak and line shape broadening with respect to pure Au NPs. The negative binding energy shift of Au 4f 7/2 peak observed in X-ray Photoelectron Spectra (XPS) indicates charge transfer in the nano-soldered Au-SnO 2 between gold and tin oxide and formation of soldered nanocomposite.

  14. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    ... Institute of Microengineering and Nanoelectronics, University Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia; Jabil Circuit Sdn. Bhd., Bayan Lepas Industrial Park, 11900 Bayan Lepas, Penang, Malaysia; Shenzhen Kunqi Xinhua Technology Co., Ltd, Gangtou, Bantian, Longgang, Shenzhen, Guangdong, China ...

  15. Effects of Ce and La Additions on the Microstructure and Mechanical Properties of Sn-9Zn Solder Joints

    Science.gov (United States)

    Lin, Hsiu-Jen; Chuang, Tung-Han

    2010-02-01

    The effects of rare-earth elements on the microstructure and mechanical properties of Sn-9Zn alloys and solder joints in ball grid array packages with Ni/Au(ENIG) surface finishes have been investigated. Metallographic observations showed that (Ce0.8Zn0.2)Sn3 and (La0.9Zn0.1)Sn3 intermetallic compounds appeared in the solder matrix of Sn-9Zn-0.5Ce and Sn-9Zn-0.5La alloys, respectively. Both fiber- and hillock-shaped tin whiskers were inhibited in the Sn-9Zn-0.5Ce solder, while tin fibers were still observed on the surface of oxidized (La0.9Zn0.1)Sn3 intermetallics in Sn-9Zn-0.5La after air exposure at room temperature. Mechanical testing indicated that the tensile strength of Sn-9Zn alloys doped with Ce and La increased significantly, and the elongation decreased, in comparison with the undoped Sn-9Zn. The bonding strengths of the as-reflowed Sn-9Zn-0.5Ce and Sn-9Zn-0.5La solder joints were also improved. However, aging treatment at 100°C and 150°C caused degradation of ball shear strength in all specimens. During the reflowing and aging processes, AuZn8 intermetallic phases appeared at the interfaces of all solder joints. In addition, Zn-rich phases were observed to migrate from the solder matrix to the solder/pad interfaces of the aged specimens.

  16. 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

    International Nuclear Information System (INIS)

    Lin, C.-T.; Hsi, C.-S.; Wang, M.-C.; Chang, T.-C.; Liang, M.-K.

    2008-01-01

    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 5 Zn 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 6 Sn 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 6 Sn 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

  17. 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.

  18. 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.

  19. Interfacial behavior and mechanical properties of aluminum foam joint fabricated by surface self-abrasion fluxless soldering

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Long, E-mail: wanlong178@163.com; Huang, Yongxian; Huang, Tifang; Lv, Zongliang; Feng, Jicai

    2016-06-25

    Fluxless soldering with surface self-abrasion has been developed for joining aluminum foams with metallic bonding. The effect of the self-abrasion on the wettability of molten solder alloy and mechanical properties is determined by microstructural observation, tension and compression tests. No apparent macroscopic deformation and collapse of foam structure are observed adjacent to the joint interface. The average tensile strength of the joints is about 14% higher than that of aluminum foam, and the compressive strength can reach 200% of that of aluminum foam. The deformation mechanisms and energy absorbing characteristics of aluminum foam and the joint are investigated. The aluminum foam joint fails primarily by bending, crushing, and compaction of cell walls and cracking of the solder seam. The interdiffusion process is explained based on thermodynamic equations. - Highlights: • Fluxless soldering with surface self-abrasion is developed for joining aluminum foam. • Excellent metallic bonding has been informed between foam cores. • The aluminum foam joint has excellent mechanical properties. • The joining mechanism of solder alloy and aluminum foam is explained.

  20. Combined Thermodynamic-Kinetic Analysis of the Interfacial Reactions between Ni Metallization and Various Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Tomi Laurila

    2009-11-01

    Full Text Available In this paper we will demonstrate how a thermodynamic-kinetic method can be utilized to rationalize a wide range of interfacial phenomena between Sn-based lead-free solders and Ni metallizations. First, the effect of P on the interfacial reactions, and thus on the reliability, between Sn-based solders and electroless Ni/immersion Au (ENIG metallizations, will be discussed. Next, the effect of small amounts of Cu in Sn-based solders on the intermetallic compound (IMC, which forms first on top of Ni metallization, will be covered. With the help of thermodynamic arguments a so called critical Cu concentration for the formation of (Cu,Ni6Sn5 can be determined as a function of temperature. Then the important phenomenon of redeposition of (Au,NiSn4 layer on top of Ni3Sn4 IMC will be discussed in detail. The reasons leading to this behaviour will be rationalized with the help of thermodynamic information and an explanation of why this phenomenon does not occur when an appropriate amount of Cu is present in the soldering system will be given. Finally, interfacial reaction issues related to low temperature Sn-Zn and Sn-Bi based solders and Ni metallization will be discussed.

  1. 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.

  2. Identification and chemical characterization of particulate matter from wave soldering processes at a printed circuit board manufacturing company

    International Nuclear Information System (INIS)

    Szoboszlai, Z.; Kertész, Zs.; Szikszai, Z.; Angyal, A.; Furu, E.; Török, Zs.; Daróczi, L.; Kiss, Á.Z.

    2012-01-01

    Highlights: ► We characterized aerosol particles in an environment where wave soldering is used. ► The constituents of the melt were recognized in the aerosols. ► Sources and creation process of PM were identified, e.g. soldering, fluxing, etching. ► Pb and other metals showed a maximum in the fine mode in the size distributions. ► Deposition probabilities of different particles along the respiratory tract were calculated. - Abstract: In this case study, the elemental composition and mass size distribution of indoor aerosol particles were determined in a working environment where soldering of printed circuit boards (PCB) took place. Single particle analysis using ion and electron microscopy was carried out to obtain more detailed and reliable data about the origin of these particles. As a result, outdoor and indoor aerosol sources such as wave soldering, fluxing processes, workers’ activity, mineral dust, biomass burning, fertilizing and other anthropogenic sources could be separated. With the help of scanning electron microscopy, characteristic particle types were identified. On the basis of the mass size distribution data, a stochastic lung deposition model was used to calculate the total and regional deposition efficiencies of the different types of particles within the human respiratory system. The information presented in this study aims to give insights into the detailed characteristics and the health impact of aerosol particles in a working environment where different kinds of soldering activity take place.

  3. Vibration characteristics of aluminum surface subjected to ultrasonic waves and their effect on wetting behavior of solder droplets.

    Science.gov (United States)

    Ma, Lin; Xu, Zhiwu; Zheng, Kun; Yan, Jiuchun; Yang, Shiqin

    2014-03-01

    The vibration characteristics of an aluminum surface subjected to ultrasonic waves were investigated with a combination of numerical simulation and experimental testing. The wetting behavior of solder droplets on the vibrating aluminum surface was also examined. The results show that the vibration pattern of the aluminum surface is inhomogeneous. The amplitude of the aluminum surface exceeds the excitation amplitude in some zones, while the amplitude decreases nearly to zero in other zones. The distribution of the zero-amplitude zones is much less dependent on the strength of the vibration than on the location of the vibration source. The surface of the liquid solder vibrates at an ultrasonic frequency that is higher than the vibration source, and the amplitude of the liquid solder is almost twice that of the aluminum surface. The vibration of the surface of the base metal (liquid solder) correlates with the oxide film removal effect. Significant removal of the oxide film can be achieved within 2s when the amplitude of the aluminum surface is higher than 5.4 μm or when the amplitude of the liquid solder surface is higher than 10.2 μm. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. On the Mutual Effect of Viscoplasticity and Interfacial Damage Progression in Interfacial Fracture of Lead-Free Solder Joints

    Science.gov (United States)

    Maleki, Milad; Cugnoni, Joel; Botsis, John

    2011-10-01

    The main goal of this paper is to shed light on the effect of strain rate and viscoplastic deformation of bulk solder on the interfacial failure of lead-free solder joints. For this purpose, interfacial damage evolution and mode I fracture behavior of the joint were evaluated experimentally by performing stable fracture tests at different strain rates employing an optimized tapered double cantilever beam (TDCB) design. The viscoplastic behavior of the solder was characterized in shear, and the constitutive parameters related to the Anand model were determined. A rate-independent cohesive zone damage model was identified to best simulate the interfacial damage progression in the TDCB tests by developing a three-dimensional (3D) finite-element (FE) model and considering the viscoplastic response of the bulk solder. The influence of strain rate on the load capability and failure mode of the joint was clarified by analyzing the experimental and simulation results. It was shown how, at the lower strain rates, the normal stress generated at the interface is limited by the significant creep relaxation developed in the bulk solder and thus is not sufficiently high to initiate interfacial damage, whereas at higher rates, a large amount of the external energy is dissipated into interfacial damage development.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Research on a fast cooling process of the spacer grids for nuclear fuel assembly after soldering-aging

    International Nuclear Information System (INIS)

    Wang Baolin; Gu Jianhua

    1997-11-01

    A fast cooling process of the spacer grids for nuclear fuel assembly after soldering-aging due to a long cycle of vacuum cooling is presented. In the process, the grids can be fast cooled down by filling with 0.06, 0.08, 0.10 and 0.12 MPa of argon into the furnace respectively at temperatures of 550 degree C, 600 degree C and 650 degree C. As a result, the cooling time is reduced to 2.5∼3 h from 15∼16 h and the soldering-aging cycle is shortened to 20 h from 33 h. The grids completely meet with the requirements for soldering on surface color, welds quality, overall dimension, rupture stress and joint thickness

  10. Analysis of the Thermal Stress for Combined Electrode of Soldered Crystalline Silicon Solar Cells under Temperature Field

    Directory of Open Access Journals (Sweden)

    He Wang

    2016-01-01

    Full Text Available Based on the theory of material mechanics and thermal stress analysis, the stress distribution of combined electrode for crystalline silicon solar module was studied for the first time. The shear stress and normal stress distribution of soldered structure for crystalline silicon solar cells under the thermal field were discussed. And the results show that the stress distribution is not simply linear relationship as some results found. But there is a stress concentration at the edge, which was considered as the true reason that caused microcracks at the edge of soldered solar cells. The conclusions we got in this paper provide a theoretical basis for deceasing the breakage rates of soldered crystalline silicon solar cells and improving the reliability of crystalline silicon solar modules.

  11. Thermal processes and solidification kinetcs of evolution of the microstructure of tin-silver-copper solder alloys

    Science.gov (United States)

    Kinyanjui, Robert Kamau

    The adoption of Sn-Ag-Cu (SAC) Pb-free solders will affect electronic manufacturing processes and joint reliability for electronics packages. Since SAC solder has a higher melting temperature than eutectic Pb-Sn solder, higher processing temperatures will be required. The higher processing temperatures can potentially affect the microstructure of these Pb-free solder joints. We investigated the effect of thermal history on the evolution of the microstructure of Sn-xAg-yCu (0 ≤ x ≤ 4.0; 0 ≤ y ≤ 1.4, concentrations are in weight percent) solder alloys. This family of alloys falls within a class of Sn-rich Sn-Ag-Cu (SAC) alloys recommended by various international consortia for implementation in electronic manufacturing industry to replace the conventional PbSn solders. This investigation was divided into three parts: part one was an investigation of an optimum SAC alloy composition devoid of large (in length scales) intermetallic compounds (IMCs) after thermal treatment. The presence of large IMCs, with different mechanical characteristics from the bulk Sn, may compromise the mechanical integrity of the Pb-free solder interconnect. In part two of this study, we examined the growth morphology of Ag3Sn, Cu6Sn 5, and betaSn in the SAC alloys. In part three, an examination of the effect of sample size on undercooling was carried out. A Sn-Ag-Cu alloy of the composition: 96.5Sn-2.6Ag-0.9Cu (in weight percent) was found to exhibit no growth of large Ag3Sn, Cu6Sn 5 intermetallic compounds at cooling rates from 0.1 to 1°C/s. However, growth of large betaSn dendrites was observed. The crystallized Sn-Ag-Cu balls were found to contain only a few Sn grains. Also the solidification temperature of the 96.5Sn-2.6Ag-yCu (0 ≤ y ≤ 1.4) solder system was found to increase with Cu content. Further, this investigation established a strong correlation between Sn-Ag-Cu sample size and degree of undercooling for these Pb-free solder alloys. The degree of undercooling of Sn in

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Kroupa A.

    2012-01-01

    Full Text Available The current state of thermodynamic modelling in the field of high-temperature lead-free soldering is presented. A consistent thermodynamic database, containing 18 elements (Ag, Al, Au, Bi, Co, Cu, Ga, Ge, Mg, Ni, P, Pb, Pd, Sb, Sn, Ti and Zn has been created. The thermodynamic data for the most of the important binary and selected ternary systems were checked and included into the database. The database was tested using major commercial software packages. Such reliable and sophisticated software coupled to reliable thermodynamic databases are necessary prerequisites for application of thermodynamics in advanced alloys design.

  15. Database of Pb - free soldering materials, surface tension and density, experiment vs. Modeling

    Directory of Open Access Journals (Sweden)

    Z Moser

    2006-01-01

    Full Text Available Experimental studies of surface tension and density by the maximum bubble pressure method and dilatometric technique were undertaken and the accumulated data for liquid pure components, binary, ternary and multicomponent alloys were used to create the SURDAT data base for Pb-free soldering materials. The data base enabled, also to compare the experimental results with those obtained by the Butler’s model and with the existing literature data. This comparison has been extended by including the experimental data of Sn-Ag-Cu-Sb alloys.

  16. 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

    and reactivity of these alloying elements, characteristics of their intermetallic compounds (IMCs) and the distribution of phases. The primary strengthening mechanism in the case of Au-Ge-In and Au-Ge-Sn combinations was determined to be the classic solute atom strengthening. The Au-Ge-Sb combination...... 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...

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

    Science.gov (United States)

    2015-05-05

    lead or the PCB pad. The latter had a very limited effect on the overall life and indeed variations in life with accelerated thermal cycling parameters...amplitude vs. aging time at 125oC for 30 mil SAC305 and SAC105 solder joints. Figure 3.4: Average rate of damage (inverse life ) vs. work per cycle for...characteristic number of cycles to failure for this assembly) Figure 3.15: The number of cycles , expressed as fraction of total life , after which cross

  18. 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 t...... (DSC). The phase equilibrium has been further investigated by thermodynamic calculations. The observed phase compositions as well as DSC signals are reasonably explained using the calculation of phase diagrams (CALPHAD) approach....

  19. 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......-SEM) in the presence of a source of gold-organic precursor gas. Bridges deposited between suspended microelectrodes show resistivities down to 10-4 Ωcm and Transmission Electron Microscopy (TEM) of the deposits reveals a dense core of gold particles surrounded by a crust of small gold nanoparticles embedded...

  20. 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....

  1. Effect of Thermal Aging on Impact Absorbed Energies of Solder Joints Under High-Strain-Rate Conditions

    Science.gov (United States)

    Zhang, Ning; Shi, Yaowu; Lei, Yongping; Xia, Zhidong; Guo, Fu; Li, Xiaoyan

    2009-10-01

    This study was concerned with the effect of thermal aging on the impact properties of solder joints. Three kinds of solders, conventional Sn-37Pb solder, Sn-3.8Ag-0.7Cu solder, and Sn-3.8Ag-0.7Cu doped with rare-earth (RE) elements, were selected to manufacture joint specimens for the Charpy impact test. U-notch specimens were adopted and isothermally aged at 150°C for 100 h and 1000 h, and then impacted by using a pendulum-type impact tester at room temperature. The Sn-37Pb solder joints exhibited higher performance in terms of impact absorbed energy in the as-soldered and 100 h thermally aged conditions. Interestingly, the Sn-3.8Ag-0.7Cu solder joints exhibited improved performance for the impact value after 1000 h of thermal aging. For the Sn-37Pb and Sn-3.8Ag-0.7Cu solder joints, the impact absorbed energies initially increased when the storage duration was limited to 100 h, and then gradually decreased with its further increase. For the Sn-3.8Ag-0.7Cu-RE specimens, impact performance decreased directly with increasing thermal aging. Furthermore, scanning electron microscopy (SEM) observation showed that the fracture paths were focused on the interface zone for the three kinds of joints in the aged conditions. For the Sn-37Pb joints, the fracture surfaces mainly presented a ductile fracture mode. For the Sn-3.8Ag-0.7Cu joints, with microstructure coarsening, crack propagation partly shifted towards the Sn/Cu6Sn5 interface. Compared with the 100 h aged joints, the area fraction of intergranular fracture of Sn grains on the Sn-3.8Ag-0.7Cu fracture surfaces was increased when the aging time was 1000 h. On the contrary, the fracture morphologies of Sn-3.8Ag-0.7Cu-RE were mainly brittle as thermal aging increased. Thus, an interrelationship between impact energy value and fracture morphology was observed.

  2. Investigation on Thermocompression Bonding Using Lead Free Sinterable Paste and High Lead Solder Paste for Power QFN Application

    Directory of Open Access Journals (Sweden)

    Chandrakasan Gunaseelan

    2016-01-01

    Full Text Available Persistently growing Power QFN packages are used in various fields especially micro-electronics, aerospace, oil and gas as well. However, the particular industries is pushing forward to reduce the use of hazardous materials in the process of manufacturing and assemblies. Thermo-compression die-attach layer is perceived to be the most critical element in power QFN packages as the increase in operating temperature requires new materials with suitable thermo-chemical properties also with suitable melting points of next generation lead free die attachment material. In this situation, Hi-lead solder (RM218: Pb92.5Sn5Ag2.5 which known as high temperature material is widely being used in most semiconductor assembly for die attach, yet it deduce few reliability challenges like solder voids, the clip tilt performance and also solder splash which has been considered as major quality issue in assembly of Power QFN packages (FET die, IC die and clip attach. As a solution, sintering epoxy paste (SPC073-3: Sn96.5/Ag3/Cu0.5 is being considered as a replacement. In this case, sintering epoxy paste demonstrating excellent electrical and thermal performance for Power QFN packages which is known to be demanded in market. Thus, this study investigates the differential pastes sintering paste and also solder paste, in order to identify best die attachment material to be used in thermo-compression bonding method. Therefore, the shear strength was resulting good indication where the sintering paste was recorded 2.4 Kg/mm meanwhile the solder paste was recorded 0Kg/mm at peak temperature of 260°C. Besides of that, the pot life seems promising as the sintering paste seems to have constant viscosity of 100Pa*s throughout the 48 hours tested while, high lead solder paste records viscosity from 100Pa*s marginally increase as the time increase which effects the inconsistency of pot life. Last but not least, the voids mechanisms proves sintering epoxy paste has the same

  3. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  4. Wafer level hermetic packaging based on Cu-Sn isothermal solidification technology

    International Nuclear Information System (INIS)

    Cao Yuhan; Luo Le

    2009-01-01

    A novel wafer level bonding method based on Cu-Sn isothermal solidification technology is established. A multi-layer sealing ring and the bonding processing are designed, and the amount of solder and the bonding parameters are optimized based on both theoretical and experimental results. Verification shows that oxidation of the solder layer, voids and the scalloped-edge appearance of the Cu 6 Sn 5 phase are successfully avoided. An average shear strength of 19.5 MPa and an excellent leak rate of around 1.9 x 10 -9 atm cc/s are possible, meeting the demands of MIL-STD-883E. (semiconductor technology)

  5. Cell interconnection without glueing or soldering for crystalline Si photovoltaic modules

    Directory of Open Access Journals (Sweden)

    Summhammer Johann

    2016-01-01

    Full Text Available In order to maximize the power output of polycrystalline silicon PV-modules, in previous work we have already tested rectangular cells of 39 × 156 mm which are overlapped along the long sides. The low current density at the cell overlap allows interconnections which need neither soldering nor glueing, but use metallic strips inserted between the cells in the overlap region. The contact is established by the pressure applied to the module during lamination and is retained by the slightly bent cells in the solidified encapsulant. Here we report on the long term stability of different contact materials and contact cross sections applied in eight modules of the 240 W class monitored for up to 24 months of outdoor operation and in a variety of small 5-cell modules exposed to rapid ageing tests with up to 1000 thermal cycles. Cells with three different electrode designs were tested and the contact materials were Cu, Ag, SnPbAg and Sn. Focussing especially on series resistance, fill factor and peak power, it is found that Ag-coated contact strips perform equally well and have practically the same stability as soldered cell interconnections. Due to 70–90% savings in copper and simpler manufacturing the cost of PV-modules may thus be reduced further.

  6. 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.

  7. A control algorithm for waveguide path induction soldering with product positioning1

    Science.gov (United States)

    Tynchenko, V. S.; Murygin, A. V.; Petrenko, V. E.; Seregin, Yu N.; Emilova, O. A.

    2017-10-01

    In the article, the problem of developing a control algorithm is described for the induction soldering process of aluminium alloy waveguide paths. The authors suggest a solution using logic controllers in two loops: controlling the speed at which product elements heat up and controlling the waveguide assembly movement relative to the plane of the inductor. The proposed solutions are based on the analysis of the thermal processes occurring in the waveguide pipe and the flange/coupler. Based on the results of numerical experiments, forms of control actions in the system and their parameters were selected. The proposed approach to generating such a control was tested in a series of waveguide path soldering field experiments and the obtained graphs showing the heating of product elements allow the efficiency of the developed logic controllers to be confirmed. The application of the proposed approach provides the high quality regulation of the induction heating process and also the possibility to obtain reliable permanent connections between elements of waveguide paths. Through the flexible adjustment of the proposed logic controller parameters, the high versatility of their use can be demonstrated.

  8. Characteristics of Creep Damage for 60Sn-40Pb Solder Material

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Y.; Chow, C.L.; Fang, H.E.; Neilsen, M.K.

    1999-08-26

    This paper presents a viscoplasticity model taking into account the effects of change in grain or phase size and damage on the characterization of creep damage in 60Sn-40Pb solder. Based on the theory of damage mechanics, a two-scalar damage model is developed for isotropic materials by introducing the free energy equivalence principle. The damage evolution equations are derived in terms of the damage energy release rates. In addition, a failure criterion is developed based on the postulation that a material element is said to have ruptured when the total damage accumulated in the element reaches a critical value. The damage coupled viscoplasticity model is discretized and coded in a general-purpose finite element program known as ABAQUS through its user-defined material subroutine UMAT. To illustrate the application of the model, several example cases are introduced to analyze, both numerically and experimentally, the tensile creep behaviors of the material at three stress levels. The model is then applied to predict the deformation of a notched specimen under monotonic tension at room temperature (22 C). The results demonstrate that the proposed model can successfully predict the viscoplastic behavior of the solder material.

  9. 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.

  10. 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.

  11. Thermophysical Properties of Sn-Ag-Cu Based Pb-Free Solders

    Science.gov (United States)

    Kim, Sok Won; Lee, Jaeran; Jeon, Bo-Min; Jung, Eun; Lee, Sang Hyun; Kang, Kweon Ho; Lim, Kwon Taek

    2009-06-01

    Lead-tin (Pb-Sn) alloys are the dominant solders used for electronic packaging because of their low cost and superior properties required for interconnecting electronic components. However, increasing environmental and health concerns over the toxicity of lead, combined with global legislation to limit the use of Pb in manufactured products, have led to extensive research and development studies of lead-free solders. The Sn-Ag-Cu ternary eutectic alloy is considered to be one of the promising alternatives. Except for thermal properties, much research on several properties of Sn-Ag-Cu alloy has been performed. In this study, five Sn-xAg-0.5Cu alloys with variations of Ag content x of 1.0 mass%, 2.5 mass%, 3.0 mass%, 3.5 mass%, and 4.0 mass% were prepared, and their thermal diffusivity and specific heat were measured from room temperature to 150 °C, and the thermal conductivity was calculated using the measured thermal diffusivity, specific heat, and density values. Also, the linear thermal expansion was measured from room temperature to 170 °C. The results show that Sn-3.5Ag-0.5Cu is the best candidate because it has a maximum thermal conductivity and a low thermal expansion, which are the ideal conditions to be a proper packaging alloy for effective cooling and thermostability.

  12. Contact angle of 63Sn-37Pb and Pb-free solder on Cu plating

    International Nuclear Information System (INIS)

    Lin, C.-T.; Lin, K.-L.

    2003-01-01

    This study investigated the wetting behavior of 63Sn-37Pb and Pb-free solder on different surface roughness Cu plating. The Cu plating roughness was controlled by current density and deposition time. The contact angles were measured to investigate the wetting behavior. The contact angles of DI (de-ionized) water obey Wenzel's equation and decrease with the increase of surface roughness. Daubing the flux on solder balls as well as on the Cu plating lowers the magnitude of contact angle by 2-23 deg. and the deviation of measured values by 4-6 deg. . The contact angles decrease with the increase of Cu substrate surface roughness in the temperature range of 250-280 deg. C. The cleaning effect of flux was analyzed by Auger electron spectroscopy. The oxide on the Cu substrate surface was well removed by flux. The carbon residue left behind on the substrate surface after reflow raises both the magnitude and the scattering of contact angle

  13. 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.

  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. FINITE ELEMENT ANALYSIS ON THE EFFECT OF SOLDER JOINT GEOMETRY FOR THE RELIABILITY OF BALL GRID ARRAY ASSEMBLY WITH FLEXIBLE AND RIGID PCBS

    Directory of Open Access Journals (Sweden)

    CHUN-SEAN LAU

    2014-02-01

    Full Text Available In the present study, three-dimensional (3D finite element simulation on 132 PIN fleXBGATM package was performed to predict the effect of solder joint geometry on the reliability of Ball Grid Array (BGA solder joints on flexible and rigid PCBs subjected to thermo-cyclic loading. The commercial FEA tool ABAQUS Version 6.9 was used for the simulations of various shapes of solder joints such as barrel, column and hourglass. Apart from a global modeling, the submodeling analysis technique (local modeling was also used on the critically affected solder joints, in order to enhance the computation efficiency. The accumulated creep strain and strain energy density were observed for each case, and optimum geometries were obtained. The model was validated with the published experimental data with the minimum percentage error of 3%. It was observed that the hourglass solder joint geometry was very crucial on the reliability of BGA solder joints, and for a given PCB, the optimal choice of hourglass solder joint geometry depended on its rigidity.

  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. The Effect Of Void Formation On The Reliability Of ED-XRF Measurements In Lead-Free Reflow Soldering

    Directory of Open Access Journals (Sweden)

    Koncz-Horváth D.

    2015-06-01

    Full Text Available In lead-free reflow soldering, the presence of voids should be taken into account. For this reason, the effect of the applied heating profiles was examined via the characterization of voids in galvanic and immersion Sn coatings. According to EU Directive 2002/95/EC, the screening of Pb element of reflow soldering (i.e. of electrical and electronic equipment is necessary; and the practical implementation of this measurement is largely affected by the characteristics of the solder (i.e. the presence of voids and the inhomogeneity of the solder. Comparing the results of the above two coating methods, it was found that by chemical coating more voids were formed and the detected lead content was higher than for galvanic Sn. The standard deviation of Ag and Cu concentrations was mainly influenced by the appearance of large compounds in the second case, while with chemical coating, no large compounds were formed due to the elevated number of voids.

  18. Histological Study of Toxic Effects of Solder Fumes on Thickness of Germinal Epithelium in Seminiferous Tubule in Rat

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Arab

    2014-10-01

    Full Text Available Background: Toxic fumes generating during soldering contains various contaminants. The aim of the study was to determine toxic effects of solder fumes in thickness of semniferous tubule in Rat. Materials and Methods 48 male adult rats were randomly divided into experimental (n=30 and control (n=18 groups. Based on exposure time, each group was further divided into three subgroups such as 2, 4 and 6 weeks. The concentrations of toxic fumes were measured by standard method. Rats of experimental group were exposed to solder fumes for 1 hour/day. According to time table rats of experimental and control subgroups were killed. After fixation of testis, paraffin sections were stained by Hematoxylin & Eosin. The thicknesses of germinal epithelium were measured and data were analyzed by SPSS software version 17 with Mann Whitney test. Results: The results showed that the concentration of fumes was 0.193 mg/m3 for formaldehyde, 0.35 mg/m3 for Stanum (Sn and 3 mg/m3 for Pb. Although there was no significant difference for weight of rats’ testis between control and experimental subgroups, there was only a significant difference for the thickness of germinal epithelium between 6 week experimental and control subgroups ( p<0.02. Conclusion: The results of study showed that solder fumes can change the structure and thickness of seminiferous epithelium in experimental groups in a time dependent manner.

  19. Soldering of Bi-2223/Ag high temperature superconducting tapes with Sn-Pb-Bi-Ag alloy paste

    Energy Technology Data Exchange (ETDEWEB)

    Guo Wei, E-mail: gwei@tsinghua.edu.c [Department of Mechanical Engineering, Key Laboratory for Advanced Manufacturing by Materials Processing Technology, Tsinghua University, Ministry of Education of PR China, Beijing 100084 (China); School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zou Guisheng; Wu Aiping; Bai Hailin; Ren Jialie [Department of Mechanical Engineering, Key Laboratory for Advanced Manufacturing by Materials Processing Technology, Tsinghua University, Ministry of Education of PR China, Beijing 100084 (China)

    2010-01-15

    Soldered joints of Bi-2223/Ag-sheathed high temperature superconducting multifilamentary tapes were fabricated using 63 wt.%Sn-34 wt.%Pb-1 wt.%Bi-2 wt.%Ag paste. The soldered joints were observed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Moreover, the electrical properties of joints were evaluated by current-voltage curves, and the tensile strengths of the joints were also tested. The results show that the soldered joint consists of Ag sheath - Ag{sub 3}Sn compound layer - PbSn{sub 2} and Ag{sub 3}Sn solder layer - Ag{sub 3}Sn compound layer - Ag sheath. The joints are obeyed with Ohms Law and the magnitude of the joint resistance, which deceases with the increase of the overlap length, can reach the order of 10{sup -8} OMEGA. The tensile strength of the joints with a brittle fracture mode is a little lower than that of the original tapes.

  20. Liquid-phase diffusion bonding: Temperature effects and solute redistribution in high temperature lead-free composite solders

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver [Ames Lab. and Iowa State Univ., Ames, IA (United States); Iowa State Univ., Ames, IA (United States); Choquette, Stephanie [Ames Lab. and Iowa State Univ., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)

    2015-05-17

    Liquid-phase diffusion bonding (LPDB) is being studied as the primary phenomena occurring in the development of a high temperature lead-free composite solder paste composed of gas-atomized Cu-10Ni, wt.% (Cu-11Ni, at.%) powder blended with Sn-0.7Cu-0.05Ni-0.01Ge (Sn-1.3Cu-0.1Ni-0.02Ge, at.%) Nihon-Superior SN100C solder powder. Powder compacts were used as a model system. LPDB promotes enhanced interdiffusion of the low-melting alloy matrix with the solid Cu-10Ni reinforcement powder above the matrix liquidus temperature. The initial study involved the effective intermetallic compound (IMC) compositions and microstructures that occur at varying reflow temperatures and times between 250-300°C and 30-60s, respectively. Certain reflow temperatures encourage adequate interdiffusion to form a continuous highly-conductive network throughout the composite solder joints. The diffusion of nickel, in particular, has a disperse pattern that foreshadows the possibility of a highly-conductive low-melting solder that can be successfully utilized at high temperatures.

  1. The shearing behavior and microstructure of Sn-4Ag-0.5Cu solder joints on a Ni-P-carbon nanotubes composite coating

    International Nuclear Information System (INIS)

    Gu, X.; Chan, Y.C.; Yang, D.; Wu, B.Y.

    2009-01-01

    This study employed an electroless Ni-P-carbon nanotubes (Ni-P-CNTs) composite coating as a pad finish for electronic packaging. It was aimed at investigating the effect of CNTs on the mechanical behavior and microstructure of ball grid array (BGA) solder joints after multiple reflows. Electroless Ni-P and electroless Ni-P-CNTs composite coatings with the same P-content were prepared for comparison. It was found that the CNTs in the coating increased the brittleness of solder joints and weakened their shear strength. After shearing tests, more brittle fractures occurred in the intermetallic compound (IMC) layer in the Sn-4Ag-0.5Cu/Ni-P-CNTs (SAC/Ni-P-CNTs) solder joints. According to the scanning electron microscope (SEM) observation, a Ni 3 Sn 4 IMC layer and a P-rich layer were formed in the solder joints on both coatings after multiple reflows. The IMC layers in the SAC/Ni-P solder joints were found to be compact with chunky-shaped grains, whilst the IMC layers in the SAC/Ni-P-CNTs solder joints were porous with needle-shaped grains. Due to the high stability of the CNTs in the metal matrix, the CNTs dispersed in the Ni-P coating acted as a retardant in the reaction of the Ni with the solder. Therefore, the growth rates of both the Ni 3 Sn 4 IMC layer and the P richer layer in the SAC/Ni-P-CNTs solder joints were slower than those in the SAC/Ni-P solder joints

  2. Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Shnawah, Dhafer Abdul-Ameer, E-mail: dhafer_eng@yahoo.com [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Said, Suhana Binti Mohd [Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Che Faxing [Institute of Microelectronics, A-STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore)

    2012-08-15

    This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn-1Ag-0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn{sub 2} intermetallic compound (IMC) particles, which produce a weak interface with the {beta}-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag{sub 3}Sn and Cu{sub 6}Sn{sub 5} IMC particles. Moreover, Fe-bearing solders have been shown to form large primary {beta}-Sn grains. The weak interface between the large FeSn{sub 2} IMC particles and the {beta}-Sn matrix together with the presence of the large primary {beta}-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary {beta}-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100 Degree-Sign C and 180 Degree-Sign C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag{sub 3}Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag{sub 3}Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn-Ag-Cu solder alloys.

  3. The effects of nucleation and solidification mechanisms on the microstructure and thermomechanical response of tin silver copper solder joints

    Science.gov (United States)

    Arfaei, Babak

    This work examines the nucleation mechanism of Sn in SnAgCu alloys and its effect on the microstructure of those solder joints. The nucleation rate of Sn in a SAC alloy was obtained by simultaneous calorimetric examination of the isothermal solidification of 88 flip chip Sn-Ag-Cu solder joints. Qualitative agreement with classic nucleation theory was observed, although it was concluded that the spherical cap model cannot be applied to explain the structure of nucleus. It was shown that the solidification temperature significantly affects the microstructure; samples that undercooled less than approximately 40oC revealed one or three large Sn grains, while interlaced twinning was observed in the samples that solidified at lower temperatures. In order to better understand the effect of microstructure on the thermomechanical properties of solder joints, a study of the dependence of room temperature shear fatigue lifetime on Sn grain number and orientation was conducted. This study examined the correlations of variations in fatigue life of solder balls with the microstructure of Sn-Ag-Cu solder. The mean fatigue lifetime was found to be significantly longer for samples with multiple Sn grains than for samples with single Sn grains. For single grain samples, correlations between Sn grain orientation (with respect to the loading direction) and lifetime were observed, providing insight on early failures in SnAgCu solder joints. Correlations between the lifetimes of single Sn grained, SAC205 solder joints with differences in Ag3Sn and Cu6Sn5 precipitate microstructures were investigated. It was found that Ag3Sn precipitates were highly segregated from Cu6Sn 5 precipitates on a length scale of approximately twenty microns. Furthermore, large (factor of two) variations of the Sn dendrite arm size were observed within given samples. Such variations in values of dendrite arm size within a single sample were much larger than observed variations of this parameter between

  4. Constitutive Behavior of Mixed Sn-Pb/Sn-3.0Ag-0.5Cu Solder Alloys

    Science.gov (United States)

    Tucker, J. P.; Chan, D. K.; Subbarayan, G.; Handwerker, C. A.

    2012-03-01

    During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of Sn-Pb and Sn-Ag-Cu often result from either mixed assemblies or rework. Comprehensive characterization of the mechanical behavior of these mixed solder alloys resulting in a deformationally complete constitutive description is necessary to predict failure of mixed alloy solder joints. Three alloys with 1 wt.%, 5 wt.%, and 20 wt.% Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn-37Pb components mixed with Sn-3.0Ag-0.5Cu. Creep and displacement-controlled tests were performed on specially designed assemblies 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. The observed changes in creep and tensile behavior with Pb additions were related to phase equilibria and microstructure differences observed through differential scanning calorimetric and scanning electron microscopic cross-sectional analysis. As Pb content increased, the steady-state creep strain rates increased, and primary creep decreased. Even 1 wt.% Pb addition was sufficient to induce substantially large creep strains relative to the Sn-3.0Ag-0.5Cu alloy. We describe rate-dependent constitutive models for Pb-contaminated Sn-Ag-Cu solder alloys, ranging from the traditional time-hardening creep model to the viscoplastic Anand model. We illustrate the utility of these constitutive models by examining the inelastic response of a chip-scale package (CSP) under thermomechanical loading through finite-element analysis. The models predict that, as Pb content increases, total inelastic dissipation decreases.

  5. 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.

  6. Utilization of a Porous Cu Interlayer for the Enhancement of Pb-Free Sn-3.0Ag-0.5Cu Solder Joint

    Directory of Open Access Journals (Sweden)

    Nashrah Hani Jamadon

    2016-09-01

    Full Text Available The joining of lead-free Sn-3.0Ag-0.5Cu (SAC305 solder alloy to metal substrate with the addition of a porous Cu interlayer was investigated. Two types of porous Cu interlayers, namely 15 ppi—pore per inch (P15 and 25 ppi (P25 were sandwiched in between SAC305/Cu substrate. The soldering process was carried out at soldering time of 60, 180, and 300 s at three temperature levels of 267, 287, and 307 °C. The joint strength was evaluated by tensile testing. The highest strength for solder joints with addition of P25 and P15 porous Cu was 51 MPa (at 180 s and 307 °C and 54 MPa (at 300 s and 307 °C , respectively. The fractography of the solder joint was analyzed by optical microscope (OM and scanning electron microscopy (SEM. The results showed that the propagation of fracture during tensile tests for solder with a porous Cu interlayer occurred in three regions: (i SAC305/Cu interface; (ii inside SAC305 solder alloy; and (iii inside porous Cu. Energy dispersive X-ray spectroscopy (EDX was used to identify intermetallic phases. Cu6Sn5 phase with scallop-liked morphology was observed at the interface of the SAC305/Cu substrate. In contrast, the scallop-liked intermetallic phase together with more uniform but a less defined scallop-liked phase was observed at the interface of porous Cu and solder alloy.

  7. 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.

  8. 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

  9. Proceedings of the Annual Soldering/Manufacturing Seminar (10th) Held in China Lake, California on 19-20 February 1986

    Science.gov (United States)

    1986-02-19

    8217 coefficient of thermal expansion ( CTE ), not just the different CTEs "- of the device and the substrate, but also of the solder itself (Ref. 9). The high...solder CTE cart be the driving force for metallurgical instability of surface mounted assemblies. Future tests are planned to correlate accelerated...manufacturing and quality related problems. 168 NWC TP 6707 To better understand the uses of statistical control charts, consider the game of football

  10. 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

  11. Mechanistic Prediction of the Effect of Microstructural Coarsening on Creep Response of SnAgCu Solder Joints

    Science.gov (United States)

    Mukherjee, S.; Chauhan, P.; Osterman, M.; Dasgupta, A.; Pecht, M.

    2016-07-01

    Mechanistic microstructural models have been developed to capture the effect of isothermal aging on time dependent viscoplastic response of Sn3.0Ag0.5Cu (SAC305) solders. SnAgCu (SAC) solders undergo continuous microstructural coarsening during both storage and service because of their high homologous temperature. The microstructures of these low melting point alloys continuously evolve during service. This results in evolution of creep properties of the joint over time, thereby influencing the long term reliability of microelectronic packages. It is well documented that isothermal aging degrades the creep resistance of SAC solder. SAC305 alloy is aged for (24-1000) h at (25-100)°C (~0.6-0.8 × T melt). Cross-sectioning and image processing techniques were used to periodically quantify the effect of isothermal aging on phase coarsening and evolution. The parameters monitored during isothermal aging include size, area fraction, and inter-particle spacing of nanoscale Ag3Sn intermetallic compounds (IMCs) and the volume fraction of micronscale Cu6Sn5 IMCs, as well as the area fraction of pure tin dendrites. Effects of microstructural evolution on secondary creep constitutive response of SAC305 solder joints were then modeled using a mechanistic multiscale creep model. The mechanistic phenomena modeled include: (1) dispersion strengthening by coarsened nanoscale Ag3Sn IMCs in the eutectic phase; and (2) load sharing between pro-eutectic Sn dendrites and the surrounding coarsened eutectic Sn-Ag phase and microscale Cu6Sn5 IMCs. The coarse-grained polycrystalline Sn microstructure in SAC305 solder was not captured in the above model because isothermal aging does not cause any significant change in the initial grain size and orientation of SAC305 solder joints. The above mechanistic model can successfully capture the drop in creep resistance due to the influence of isothermal aging on SAC305 single crystals. Contribution of grain boundary sliding to the creep strain of

  12. 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

  13. Massive spalling of Cu-Zn and Cu-Al intermetallic compounds at the interface between solders and Cu substrate during liquid state reaction

    Science.gov (United States)

    Kotadia, H. R.; Panneerselvam, A.; Mokhtari, O.; Green, M. A.; Mannan, S. H.

    2012-04-01

    The interfacial intermetallic compound (IMC) formation between Cu substrate and Sn-3.8Ag-0.7Cu-X (wt.%) solder alloys has been studied, where X consists of 0-5% Zn or 0-2% Al. The study has focused on the effect of solder volume as well as the Zn or Al concentration. With low solder volume, when the Zn and Al concentrations in the solder are also low, the initial Cu-Zn and Al-Cu IMC layers, which form at the solder/substrate interface, are not stable and spall off, displaced by a Cu6Sn5 IMC layer. As the total Zn or Al content in the system increases by increasing solder volume, stable CuZn or Al2Cu IMCs form on the substrate and are not displaced. Increasing concentration of Zn has a similar effect of stabilizing the Cu-Zn IMC layer and also of forming a stable Cu5Zn8 layer, but increasing Al concentration alone does not prevent spalling of Al2Cu. These results are explained using a combination of thermodynamic- and kinetics-based arguments.

  14. FEM simulation of the size- and constraining effect in lead- free solder joints with the theory of strain gradient elasticity

    Science.gov (United States)

    Lederer, M.; Magnien, J.; Khatibi, G.; Weiss, B.

    2015-04-01

    Reliability studies of electronic parts prevalently involve FEM simulations of solder joints under service conditions. However, simulations performed with classical continuum mechanics lead to strain singularities at the surface of material transitions. In consequence, the desired independence of the results from mesh size can usually not be achieved. Therefore, we propose a novel version of strain gradient elasticity which consequently removes strain singularities. Our approach shows similarities to a strain gradient theory which was developed already in the 1960s. But in our version of the theory it is required that the stress tensor of equilibrium states is always symmetric. This approach is implemented in the commercial FEM code ABAQUS through user subroutine UEL. Thus, it is demonstrated that in the new approach mesh convergence is achieved. Furthermore, simulations for solder joints of different sizes predict a mechanical size effect in the sense “smaller is stronger”.

  15. Aging effects on the microstructure, surface characteristics and wettability of Cu pretinned with Sn-Pb solders

    Energy Technology Data Exchange (ETDEWEB)

    Linch, Heidi Sue [Univ. of California, Berkeley, CA (United States)

    1993-11-01

    This study investigates effects of aging in air and argon at 170 C on Cu coupons which were pretinned with 75Sn-25Pb, 8Sn-92Pb, and 5Sn-95Pb solders. Coatings were applied using electroplating or hot dipping techniques. The coating thickness was controlled between 3 to 3μm and the specimens were aged for 0 hours, 2 hours, 24 hours and 2 weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using X-ray diffraction, energy dispersive X-ray and Auger spectroscopy, as well as optical and scanning electron microscopy. The wetting behavior of the test specimens is interpreted with respect to observed microstructural changes and as a function of aging time, solder composition, and processing conditions.

  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. 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...... phases of the Au-Sn system. The measured values are comparable to those found in the literature. An outlook to further research is also given....

  18. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  19. 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

  20. A thermodynamics based damage mechanics framework for fatigue analysis of microelectronics solder joints with size effects

    Science.gov (United States)

    Gomez, Juan

    Experimental observations of an increase in resistance with decreasing specimen size and under the presence of non-uniform plastic deformation fields have pushed the development for small scale plasticity theories since the early 90's. The observed phenomenon has been explained in terms of an accumulation of a density of geometrically necessary dislocations, which is required in order to accommodate nonuniform plastic deformation fields. This extra density of dislocations, contributes to the additional hardening observed in small scale specimens under imposed non-uniform plastic deformations. The density of geometrically necessary dislocations has been related to the gradients of plastic strain which are imposed either by the loading conditions or the geometry of the specimen. The proposed set of theories has promoted the idea that there is an additional material parameter, namely a plastic length scale. Within these theories when the material is under the presence of a non-uniform plastic deformation field and once typical structural dimensions approaches the material length scale there is an increase in resistance. Such a class of mathematical framework is currently known as strain gradient plasticity (SGP) theory. On the other hand, the current trend towards miniaturization in the microelectronics industry has raised questions about the true behavior of small structural systems. In this dissertation we address such a problem but from the perspective of eutectic solder alloys. Eutectic solder alloys as frequently used in the microelectronics industry exhibit considerable rate dependent response even at room temperature. Moreover for this type of material, the problem of interest is the response under cyclic loadings induced by thermomechanical fatigue leading to the classical case of creep-fatigue interaction. Several experimental and theoretical studies have been developed in order to generate robust constitutive descriptions for this class of applications. For

  1. Effects of thermal annealing in the post-reflow process on microstructure, tin crystallography, and impact reliability of Sn–Ag–Cu solder joints

    International Nuclear Information System (INIS)

    Chen, Wen-Lin; Yu, Chi-Yang; Ho, Cheng-Ying; Duh, Jenq-Gong

    2014-01-01

    This study aims to investigate the microstructure, β-Sn crystallography, micro-hardness and impact reliability of both Sn–3.0Ag–0.5Cu/Cu (SAC/Cu) and Sn–3.0Ag–0.5Cu/Ni (SAC/Ni) solder joints under various reflow processes. During the solidification step of the reflow process, solder joints were annealed at 210 °C for 50 s and 100 s, respectively. Network-type precipitations formed within the SAC/Cu joint, while dot-type precipitations distributed within the SAC/Ni joint. With the increase of annealing time, these precipitations grew larger; the interfacial intermetallic compounds (IMCs) became slightly thicker, and the hardness of solder alloys gradually decreased. Electron backscatter diffraction (EBSD) analysis indicates that the β-Sn grain structure depended on the distribution of precipitations. A high speed shear tester was used to evaluate the impact toughness of solder joints. Noteworthily, the short-time annealing can improve the impact reliability of solder joints. After annealing for 50 s, the average impact toughness of both SAC/Cu and SAC/Ni solder joints was enhanced, and the percentage of ductile fracture increased significantly. However, the growth of (Cu,Ni) 6 Sn 5 at the SAC/Ni interface degraded the impact toughness as the SAC/Ni joint was annealed for 100 s. The variation of impact toughness in SAC/Cu and SAC/Ni is correlated to the variation of microstructure and hardness in solder joints

  2. Technology

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2016-01-01

    Full Text Available The traditional answer card reading method using OMR (Optical Mark Reader, most commonly, OMR special card special use, less versatile, high cost, aiming at the existing problems proposed a method based on pattern recognition of the answer card identification method. Using the method based on Line Segment Detector to detect the tilt of the image, the existence of tilt image rotation correction, and eventually achieve positioning and detection of answers to the answer sheet .Pattern recognition technology for automatic reading, high accuracy, detect faster

  3. Environmental factors and uptake of cadmium among brazers using cadmium-containing hard solders.

    Science.gov (United States)

    Lundberg, I; Sjögren, B; Hallne, U; Hedström, L; Holgersson, M

    1984-06-01

    The influence of different work factors on the uptake of cadmium has been studied in 102 brazers working at least 10% of their work day with cadmium-containing hard solders. The blood concentrations of cadmium varied between less than 1 and 113 micrograms/L (less than 9 and 1010 nmol/L). Blood cadmium concentrations were below 10 micrograms/L (89 nmol/L) in 71 brazers and 31 brazers had levels equal to or above that value. The importance of some environmental factors on the blood-level of cadmium was studied with discrimination analysis. The length of the splice was found to be almost the sole determining factor for the cadmium concentration in blood. All brazers working with splices shorter than 2 cm had blood concentrations below 10 micrograms/L, while 87% of the brazers working with splices longer than 10 cm had blood concentrations equal to or above 10 micrograms/L. Other factors like age, sex, exposure time, smoking habit and brazing method were devoid of any measurable importance.

  4. Selective separation of copper over solder alloy from waste printed circuit boards leach solution.

    Science.gov (United States)

    Kavousi, Maryam; Sattari, Anahita; Alamdari, Eskandar Keshavarz; Firozi, Sadegh

    2017-02-01

    The printed circuit boards (PCBs) from electronic waste are important resource, since the PCBs contain precious metals such as gold, copper, tin, silver, platinum and so forth. In addition to the economic point of view, the presence of lead turns this scrap into dangerous to environment. This study was conducted as part of the development of a novel process for selective recovery of copper over tin and lead from printed circuit boards by HBF 4 leaching. In previous study, Copper with solder alloy was associated, simultaneously were leached in HBF 4 solution using hydrogen peroxide as an oxidant at room temperature. The objective of this study is the separation of copper from tin and lead from Fluoroborate media using CP-150 as an extractant. The influence of organic solvent's concentration, pH, temperature and A/O phase ratio was investigated. The possible extraction mechanism and the composition of the extracted species have been determined. The separation factors for these metals using this agent are reported, while efficient methods for separation of Cu (II) from other metal ions are proposed. The treatment of leach liquor for solvent extraction of copper with CP-150 revealed that 20% CP-150 in kerosene, a 30min period of contact time, and a pH of 3 were sufficient for the extraction of Cu(II) and 99.99% copper was recovered from the leached solution. Copyright © 2016. Published by Elsevier Ltd.

  5. 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.

  6. Indentation Size Effect on Ag Nanoparticle-Modified Graphene/Sn-Ag-Cu Solders

    Science.gov (United States)

    Xu, L. Y.; Zhang, S. T.; Jing, H. Y.; Wang, L. X.; Wei, J.; Kong, X. C.; Han, Y. D.

    2018-01-01

    This paper presents the results for the indentation size effect (ISE) on the creep stress exponent and hardness of 0.03 wt.% Ag-modified graphene nanosheet Sn-Ag-Cu solder alloys, using constant loading/holding and multi-cycle (CMC) loading methods, respectively. At each maximum load, with increasing indentation depth, the creep exponent first decreased and then increased. At the same strain rate, the stress exponent also showed the same tendency, increasing as the indentation depth (peak load) increased and then decreased. The hardness was measured continuously with increasing indentation depth by the CMC loading method. The hardness did not exhibit a decrease as the indentation depth increased, which differs from the classical description of the ISE. After an initial decrease, the hardness then increased and finally decreased as the indentation depth increased. This study reviews the existing theories and formulations describing ISE with hardening effects. The experimental results fit well with the empirical formulation. The phenomenon of ISE accompanied by hardening effects has been explained physically via the interaction between geometrically necessary dislocations and grain boundaries.

  7. 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.

  8. 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.

  9. Occupational exposure to dioxins by thermal oxygen cutting, welding, and soldering of metals.

    Science.gov (United States)

    Menzel, H M; Bolm-Audorff, U; Turcer, E; Bienfait, H G; Albracht, G; Walter, D; Emmel, C; Knecht, U; Päpke, O

    1998-04-01

    This paper focuses on one aspect of occupational dioxin exposure that is novel and unexpected. Exposures in excess of the German threshold limit value of 50 pg international toxicity equivalent (I-TEQ)/m3 are very frequent, unpredictable, and sometimes very high--up to 6612 pg I-TEQ/m3--during thermal oxygen cutting at scrap metal and demolition sites. The same procedure involving virgin steel in steel trade and mass production of steel objects gave no such evidence, even though no final conclusions can be drawn because of the low number of samples analyzed. Low dioxin exposures during inert gas electric arc welding confirm previous literature findings, whereas soldering and thermal oxygen cutting in the presence of polyvinyl chloride give rise to concern. The consequences of occupational dioxin exposure were studied by analysis of the dioxin-blood concentration, the body burden, of men performing thermal oxygen cutting at scrap metal reclamation and demolition sites, in steel trade and producing plants as well as for industrial welders and white-collar workers. The results concerning body burdens are in excellent agreement with the dioxin exposure as characterized by dioxin air concentration in the workplace. The significant positive correlation between duration and frequency of performing thermal oxygen cutting at metal reclamation and demolition sites expressed in job-years and dioxin body burden speaks for the occupational origin of the observed overload after long times. The results reported here lead to consequences for occupational health, which are discussed and require immediate attention.

  10. Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering

    Science.gov (United States)

    Çınar, Simge; Tevis, Ian D.; Chen, Jiahao; Thuo, Martin

    2016-02-01

    Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate (‘/’ = physisorbed, ‘-’ = chemisorbed), from molten Field’s metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.

  11. Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering.

    Science.gov (United States)

    Çınar, Simge; Tevis, Ian D; Chen, Jiahao; Thuo, Martin

    2016-02-23

    Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate ('/' = physisorbed, '-' = chemisorbed), from molten Field's metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.

  12. Gelatin based on Power-gel.TM. as solders for Cr.sup.4+laser tissue welding and sealing of lung air leak and fistulas in organs

    Science.gov (United States)

    Alfano, Robert R.; Tang, Jing; Evans, Jonathan M.; Ho, Peng Pei

    2006-04-25

    Laser tissue welding can be achieved using tunable Cr.sup.4+ lasers, semiconductor lasers and fiber lasers, where the weld strength follows the absorption spectrum of water. The use of gelatin and esterified gelatin as solders in conjunction with laser inducted tissue welding impart much stronger tensile and torque strengths than albumin solders. Selected NIR wavelength from the above lasers can improve welding and avoid thermal injury to tissue when used alone or with gelatin and esterified gelatin solders. These discoveries can be used to enhance laser tissue welding of tissues such as skin, mucous, bone, blood vessel, nerve, brain, liver, pancreas, spleen, kidney, lung, bronchus, respiratory track, urinary tract, gastrointestinal tract, or gynecologic tract and as a sealant for pulmonary air leaks and fistulas such as intestinal, rectal and urinary fistulas.

  13. 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.

  14. Thermal cyclic test for Sn-4Ag-0.5Cu solders on high P Ni/Au and Ni/Pd/Au surface finishes

    Directory of Open Access Journals (Sweden)

    M.A. Azmah Hanim

    2015-12-01

    Full Text Available In electronic packaging, the reliability of the interconnection changes with the surface finish and the type of solders being used. Thermal cycling is one method of reliability assessment. In thermal cycling experiments, the strain state is simplified by soldering together regular shaped pieces of materials with different coefficients of thermal expansion and exposing the joint to repeated fluctuations of temperature within a certain range. Thus, this study focuses on the intermetallic evolution of Sn-4Ag-0.5Cu on Ni/Au and Ni/Pd/Au surface finishes with thermal cycling up to 1000 cycles with the range of temperature varying from 10 to 80 °C. Sandwich samples were prepared by placing solder balls of Sn-4Ag-0.5Cu between two substrates of two different surface finishes: Ni/Au and Ni/Pd/Au. Optical microscope and FESEM (Field emission scanning electron microscope were used to analyze the samples. From the study, it was observed that the intermetallic changes from (Cu, Ni6Sn5 to (Ni, Cu3Sn4 after 1000 thermal cycles for Ni/Au. These changes promote the formation of cracks at the solder joint because of the different mechanical properties between Ni-Sn based intermetallic and Cu-Sn intermetallics. However, for the Ni/Pd/Au surface finishes, no cracks formed after thermal cycling up to 1000 cycles. This shows that the reliability of the solder joint is higher for Ni/Pd/Au surface finishes in this experiment. Based on these results, it can be concluded that the reliability of the Ni/Pd/Au surface finishes with Sn-4Ag-0.5Cu solders is higher within the given condition of this research.

  15. Size and constraint effects on mechanical and fracture behavior of micro-scale Ni/Sn3.0Ag0.5Cu/Ni solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Qin, H.B. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Zhang, X.P., E-mail: mexzhang@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Zhou, M.B.; Zeng, J.B. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Mai, Y.-W. [Centre for Advanced Materials Technology (CAMT), School of Aerospace, Mechanical and Mechatronic Engineering J07, The University of Sydney, NSW 2006 (Australia)

    2014-11-03

    Solder joints are generally regarded as the weakest part in packaging systems and electronic assemblies in modern electronic products and devices. In this study, both experimental and finite element methods were used to characterize the mechanical behavior of micro-scale Ni/Sn3.0Ag0.5Cu/Ni sandwich-structured joints with different thickness-to-diameter ratios (R varying from 1/3 to 1/12) under quasi-static tension loading using a dynamic mechanical analyzer (DMA). Experimental results show that crack initiation and propagation in the solder matrix occur in a typical ductile manner. Compared with Cu/Sn3.0Ag0.5Cu/Cu sandwich-structured solder joints, Ni/Sn3.0Ag0.5Cu/Ni solder joints have much higher tensile strengths due to the dispersion strengthening effect through the fine Ag{sub 3}Sn particles. With decreasing R, both stiffness and tensile strength of solder joints increase obviously with decreasing coefficient of stress state and damage equivalent stress. Moreover, results of quantitative fractographic analysis by SEM and EDS display three fracture modes with decreasing R. Joints with R≥1/4 all fail by ductile fracture, those with R=1/6 fail by either ductile fracture or mixed ductile and brittle fractures, and for joints with R=1/12, brittle fracture is dominant. Furthermore, results obtained have also shown that the crack growth driving forces, K{sub I} and K{sub II}, as well as the strain energy release rate, G{sub I}, in the Ni{sub 3}Sn{sub 4} layer and at the Ni{sub 3}Sn{sub 4}/Ni interface, increase significantly with decreasing R. Hence, under tensile loading the fracture mode of solder joints changes from ductile to brittle as R is decreased.

  16. Study of 3D solder-paste profilometer by dual digital fringe projection

    Science.gov (United States)

    Juan, Yi-Hua; Yih, Jeng-Nan; Cheng, Nai-Jen

    2013-09-01

    In a 3D profilometer by the fringe projection, the shadow will be produced inevitably, thus the fringes cannot be detected in the region of the shadow. In addition, a smooth surface or a metal surface produces the specular reflection, and then, no projection fringe can be recorded in the region of oversaturation on CCD. This paper reveals a proposed system for improved these defects and shows some preliminary improved 3D profiles by the proposed dual fringe projection. To obtain the profile of sample hided in the shadow and the oversaturation, this study used the dual-projection system by two projectors. This system adopted two different directions of fringe projection and illuminates them alternately, therefore, the shadow and the oversaturation produced in their corresponding locations. Two raw 3D profiles obtained from taking the dual-projection by the four-step phase-shift. A set of algorithms used to identify the pixels of the shadow and the oversaturation, and create an error-map. According to the error-map to compensate, two 3D profiles merged into an error-reduced 3D profile. We used the solder paste as a testing sample. After comparatively analyzing the 3D images obtained by our measurement system and by a contact stylus profilometer, the result shows that our measurement system can effectively reduce the error caused by shadows and oversaturation. Fringe projection system by using a projector is a non-contact, full field and quickly measuring system. The proposed dual-projection by dual-projectors can effectively reduce the shadow and the oversaturation errors and enhance the scope of application of the 3D contour detection, especially in the detection of precision structure parts with specular reflection.

  17. Influence of Activated Carbon Particles on Intermetallic Compound Growth Mechanism in Sn-Cu-Ni Composite Solder

    Directory of Open Access Journals (Sweden)

    Ramli M.I.I.

    2016-01-01

    Full Text Available The influence of Activated Carbon (AC particles on mechanical properties of Sn-Cu-Ni-xAC solder joint was investigated. Five different Activated Carbon (AC percentage addition (0 wt. %, 0.25 wt. %, 0.5 wt. %, 0.75 wt. %, and 1.0 wt. % were prepared via powder metallurgy (PM technique. Interfacial IMC thickness measurement and shear strength results showed that with thinner IMC layer (by increasing amount of wt.% of AC, the higher the shear strength of the joint. It is believed that the AC particles suppresses the interfacial IMC growth and thus improves the shear strength.

  18. Solder Flux Residues and Humidity-Related Failures in Electronics: Relative Effects of Weak Organic Acids Used in No-Clean Flux Systems

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    This paper presents the results of humidity testing of weak organic acids (WOAs), namely adipic, succinic, glutaric, dl-malic, and palmitic acids, which are commonly used as activators in no-clean solder fluxes. The study was performed under humidity conditions varying from 60% relative humidity...... increase of leakage currents and probability of electrochemical migration was observed at humidity levels above the RH corresponding to the deliquescence point of WOAs present as contaminants on the printed circuit boards. The results suggest that use of solder fluxes with WOAs having higher deliquescence...

  19. 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.

  20. 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

  1. Impact of Fe powder sintering and soldering in production of porous heating surface on flow boiling heat transfer in minichannels

    Science.gov (United States)

    Depczyński, Wojciech; Piasecki, Artur; Piasecka, Magdalena; Strąk, Kinga

    2017-10-01

    This paper focuses on identification of the impact of porous heated surface on flow boiling heat transfer in a rectangular minichannel. The heated element for Fluorinert FC-72 was a thin plate made of Haynes-230. Infrared thermography was used to determine changes in the temperature on its outer smooth side. The porous surface in contact with the fluid in the minichannel was produced in two processes: sintering or soldering of Fe powder to the plate. The results were presented as relationships between the heat transfer coefficient and the distance from the minichannel inlet and as boiling curves. Results obtained for using a smooth heated plate at the saturated boiling region were also presented to compare. In the subcooled boiling region, at a higher heat flux, the heat transfer coefficient was slightly higher for the surface prepared via soldering. In the saturated boiling region, the local heat transfer coefficients obtained for the smooth plate surface were slightly higher than those achieved from the sintered plate surface. The porous structures formed have low thermal conductivity. This may induce noticeable thermal resistance at the diffusion bridges of the sintered structures, in particular within the saturated boiling region.

  2. Large area photonic flash soldering of thin chips on flex foils for flexible electronic systems: In situ temperature measurements and thermal modelling

    NARCIS (Netherlands)

    Ende, D.A. van den; Hendriks, R.; Cauchois, R.; Groen, W.A.

    2014-01-01

    In this work photonic energy from a high power xenon flash lamp is used for soldering thin chips on polyimide and polyester foil substrates using standard Sn-Ag-Cu lead free alloys. The absorption of the xenon light pulse leads to rapid heating of components and tracks up to temperatures above the

  3. 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.

  4. 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.

    Science.gov (United States)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-11-01

    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. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A comparative evaluation of the tensile strength of silver soldered joints of stainless steel and cobalt chromium orthodontic wires with band material--an in vitro study.

    Science.gov (United States)

    Dua, R; Nandlal, B

    2004-03-01

    The present study was conducted to compare and evaluate the tensile strength of silver soldered joints of stainless steel and cobalt-chromium orthodontic wires with band material. An attempt was made to observe the effect of joint site preparation by incorporation of tack welding and increasing metal to metal surface contact area by flattening an end of the wire prior to soldering along with the regularly used round wires without tack welding. A total of 180 wire specimens were soldered to 180 band specimens. Fifteen samples according to joint site preparation were included for each of the wire groups i.e. Gloria (S.S.), Remanium (S.S.) and Remaloy (Co-Cr) wires of 0.036" in diameter. The findings of the study were suggestive that all three wires may be used for preparing silver soldered joints irrespective of the quality of the wire. However, when subjecting the wire to joint site preparation, Gloria (S.S.) wire showed less tensile strength as compared to Remanium and Remaloy.

  6. The Effects of Antimony Addition on the Microstructural, Mechanical, and Thermal Properties of Sn-3.0Ag-0.5Cu Solder Alloy

    Science.gov (United States)

    Sungkhaphaitoon, Phairote; Plookphol, Thawatchai

    2018-02-01

    In this study, we investigated the effects produced by the addition of antimony (Sb) to Sn-3.0Ag-0.5Cu-based solder alloys. Our focus was the alloys' microstructural, mechanical, and thermal properties. We evaluated the effects by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), and a universal testing machine (UTM). The results showed that a part of the Sb was dissolved in the Sn matrix phase, and the remaining one participated in the formation of intermetallic compounds (IMCs) of Ag3(Sn,Sb) and Cu6(Sn,Sb)5. In the alloy containing the highest wt pct Sb, the added component resulted in the formation of SnSb compound and small particle pinning of Ag3(Sn,Sb) along the grain boundary of the IMCs. Our tests of the Sn-3.0Ag-0.5Cu solder alloys' mechanical properties showed that the effects produced by the addition of Sb varied as a function of the wt pct Sb content. The ultimate tensile strength (UTS) increased from 29.21 to a maximum value of 40.44 MPa, but the pct elongation (pct EL) decreased from 48.0 to a minimum 25.43 pct. Principally, the alloys containing Sb had higher UTS and lower pct EL than Sb-free solder alloys due to the strengthening effects of solid solution and second-phase dispersion. Thermal analysis showed that the alloys containing Sb had a slightly higher melting point and that the addition amount ranging from 0.5 to 3.0 wt pct Sb did not significantly change the solidus and liquidus temperatures compared with the Sb-free solder alloys. Thus, the optimal concentration of Sb in the alloys was 3.0 wt pct because the microstructure and the ultimate tensile strength of the SAC305 solder alloys were improved.

  7. Analysis of a short beam with application to solder joints: could larger stand-off heights relieve stress?

    Science.gov (United States)

    Suhir, Ephraim

    2015-08-01

    Physically meaningful and easy-to-use analytical (mathematical) stress model is developed for a short beam with clamped and known-in-advance offset ends. The analysis is limited to elastic deformations. While the classical Timoshenko short-beam theory seeks the beam's deflection caused by the combined bending and shear deformations for the given loading, an inverse problem is considered here: the lateral force is sought for the given ends offset. In short beams this force is larger than in long beams, since, in order to achieve the given displacement (offset), the applied force has to overcome both bending and shear resistance of the beam. It is envisioned that short beams could adequately mimic the state of stress in solder joint interconnections, including ball-grid-array (BGA) systems, with large, compared to conventional joints, stand-off heights. When the package/printed-circuit-board (PCB) assembly is subjected to the change in temperature, the thermal expansion (contraction) mismatch of the package and the PCB results in an easily predictable relative displacement (offset) of the ends of the solder joint. This offset can be determined from the known external thermal mismatch strain (determined as the product of the difference in the coefficients of thermal expansion and the change in temperature) and the position of the joint with respect to the mid-cross-section of the assembly. The maximum normal and shearing stresses could be viewed as suitable criteria of the beam's (joint's) material long-term reliability. It is shown that these stresses can be brought down by employing beam-like joints, i.e., joints with an increased stand-off height compared to conventional joints. It is imperative, of course, that, if such joints are employed, there is still enough interfacial real estate, so that the BGA bonding strength is not compromised. On the other hand, owing to the lower stress level, reliability assurance might be much less of a challenge than in the case of

  8. 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.

  9. 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

    in the case of the Au-Ge-In candidate alloy. The microhardness measurement is well correlated with the solubility and reactivity of these alloying elements, characteristics of their intermetallic compounds (IMCs) and the distribution of phases. The primary strengthening mechanism in the case of 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....... The distribution of phases played a relatively more crucial role in determining the ductility of the bulk solder alloy. The findings of this work are: the addition of Sb to the Au-Ge eutectic would not only decrease its melting point but would also improve its ductility substantially and the lattice strains...

  10. Creep-constitutive behavior of Sn-3.8Ag-0.7Cu solder using an internal stress approach

    Science.gov (United States)

    Rist, Martin A.; Plumbridge, W. J.; Cooper, S.

    2006-05-01

    The experimental tensile creep deformation of bulk Sn-3.8Ag-0.7Cu solder at temperatures between 263 K and 398 K, covering lifetimes up to 3,500 h, has been rationalized using constitutive equations that incorporate structure-related internal state variables. Primary creep is accounted for using an evolving internal back stress, due to the interaction between the soft matrix phase and a more creep-resistant particle phase. Steady-state creep is incorporated using a conventional power law, modified to include the steady-state value of internal stress. It is demonstrated that the observed behavior is well-fitted using creep constants for pure tin in the modified creep power law. A preliminary analysis of damage-induced tertiary creep is also presented.

  11. Reliability Assessment of Solder Joints in Power Electronic Modules by Crack Damage Model for Wind Turbine Applications

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2011-01-01

    Wind turbine reliability is an important issue for wind energy cost minimization, especially by reduction of operation and maintenance costs for critical components and by increasing wind turbine availability. To develop an optimal operation and maintenance plan for critical components......, it is necessary to understand the physics of their failure and be able to develop reliability prediction models. Such a model is proposed in this paper for an IGBT power electronic module. IGBTs are critical components in wind turbine converter systems. These are multi-layered devices where layers are soldered...... and propagation processes is discussed. A statistical analysis is performed for appropriate model parameter selection. Based on the proposed model, a layout for component life prediction with crack movement is described in details....

  12. Invariant Theory (IT) & Standard Monomial Theory (SMT)

    Indian Academy of Sciences (India)

    2013-07-06

    Jul 6, 2013 ... Imagine several points in the (usual 2-dimensional) plane, say 4 of them, coloured red, blue, green, and yellow, scattered around a given central point. Introducing co-ordinate axes in the usual fashion (with origin at the central point), we can represent the points by ordered pairs (xred, yred), (xblue, yblue), ...

  13. Invariant Theory (IT) & Standard Monomial Theory (SMT)

    Indian Academy of Sciences (India)

    2013-07-06

    Jul 6, 2013 ... Introducing co-ordinate axes in the usual fashion (with origin at the central point), we can represent the points by ordered pairs (xred, yred), (xblue, yblue), (xgreen, ygreen),. (xyellow, yyellow). ..... What are the (polynomial) invariants in this case? The dot products x2 red + y2 red, . . . (of every point with itself) ...

  14. Microstructural Modification of Sn-0.7Cu Solder Alloys by Fe/Bi-Addition for Achieving High Mechanical Performance

    Science.gov (United States)

    Ali, Bakhtiar; Sabri, Mohd Faizul Mohd; Said, Suhana Mohd; Mahdavifard, Mohammad Hossein; Sukiman, Nazatul Liana; Jauhari, Iswadi

    2017-08-01

    In this work, we studied the Fe/Bi-bearing tin-copper (Sn-0.7Cu) solders for their microstructural and mechanical properties. The microstructure was studied using field emission scanning electron microscopy (FESEM) with a backscattered electron (BSE) detector, x-ray diffraction (XRD) analysis, and energy-dispersive x-ray spectroscopy (EDX). The microstructure study showed that Fe forms very few FeSn2 intermetallic compounds (IMCs) and does not significantly alter the microstructure of Sn-0.7Cu, whereas Bi controls the size of inter-dendritic regions containing Cu6Sn5 and Ag3Sn IMCs of the alloy, as well as significantly refines its primary β-Sn dendrites. Moreover, Bi atoms dissolve in β-Sn matrix, which in turn strengthen the solder by the Bi solid solution strengthening mechanism. Such microstructural modification leads to significant improvements in various mechanical properties of the alloy, including shear strength, impact toughness, and hardness values. Shear tests were performed with a 0.25 mm/min shear speed. The results showed that shear strength improves from 16.57 MPa to 38.36 MPa with the addition of Fe/Bi to Sn-0.7Cu, raising by about 130%. The energy absorbed during impact tests was measured for samples with the help of a Charpy impact testing machine with a 5.4 m/s impact speed. The results revealed that the addition of Fe/Bi to Sn-0.7Cu improves its impact absorbed energy by over 35%, increasing it from 7.5 J to 10.3 J. Vickers hardness tests were carried out for the test samples with a 245.2 mN applied load and 10 s dwell time. The results showed that the hardness number improves from 9.89 to 24.13 with Fe/Bi to Sn-0.7Cu, increasing by about 140%.

  15. Improved creep resistance and thermal behavior of Ni-doped Sn–3.0Ag–0.5Cu lead-free solder

    Energy Technology Data Exchange (ETDEWEB)

    El-Daly, A.A., E-mail: dreldaly11@yahoo.com [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); El-Taher, A.M. [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); Dalloul, T.R. [Physics Department, Faculty of Science, Islamic Univ. of Gaza, Gaza, Palestine (Country Unknown)

    2014-02-25

    Highlights: • Small amounts of Ni (x = 0–1.0) have been added into SAC(305) solder. • Ni additions enhanced the formation of new (Cu, Ni){sub 6}Sn{sub 5} IMCs. • Ni can effectively reduce the undercooling and solidus melting temperature. • The SAC(305)–0.5%Ni solder reveals the maximum creep resistance and total fracture time. • Correlations between the microstructure and creep parameters were analyzed. -- Abstract: To develop lead-free solders for advance electrical components, a series of Sn–3.0Ag–0.5Cu (SAC 305) solders containing small amounts of Ni have been investigated. Results showed that the addition of Ni not only decreased the amount of undercooling by about 7.9–8.5 °C, but also reduced the solidus temperature of SAC(305) solder from 219.9 to 216.2 °C. Microstructure analysis revealed that Ni could replace the Cu atoms in the Cu{sub 6}Sn{sub 5} phase and generates a new η-(Cu, Ni){sub 6}Sn{sub 5} IMC phase containing large amount of Ni after 0.5%Ni addition. The high solubility of Ni in Cu{sub 6}Sn{sub 5} increased the substitutional defects and generated inter-atomic stress around Ni atoms, which in turn impeded the dislocation movements in different crystal directions, resulting in an increase in the creep resistance and total fracture time of 0.5%Ni-doped SAC(305) solder. In addition, the formation of fine fiber-like Ag{sub 3}Sn and finer dot-shaped precipitates at the surface of β-Sn matrix could provide more obstacles for dislocation pile up in the adjacent grains and enhanced the creep resistance. However, when the concentration of Ni exceeded 0.5 wt%, the benefits of creep behavior and fracture time were reduced due to the formation of small amount of abrasive Ag{sub 3}Sn and coarsening of (Cu, Ni){sub 6}Sn{sub 5} IMCs in the eutectic colony.

  16. Quantifying Electromigration Processes in Sn-0.7Cu Solder with Lab-Scale X-Ray Computed Micro-Tomography

    Science.gov (United States)

    Mertens, James Charles Edwin

    For decades, microelectronics manufacturing has been concerned with failures related to electromigration phenomena in conductors experiencing high current densities. The influence of interconnect microstructure on device failures related to electromigration in BGA and flip chip solder interconnects has become a significant interest with reduced individual solder interconnect volumes. A survey indicates that x-ray computed micro-tomography (muXCT) is an emerging, novel means for characterizing the microstructures' role in governing electromigration failures. This work details the design and construction of a lab-scale muXCT system to characterize electromigration in the Sn-0.7Cu lead-free solder system by leveraging in situ imaging. In order to enhance the attenuation contrast observed in multi-phase material systems, a modeling approach has been developed to predict settings for the controllable imaging parameters which yield relatively high detection rates over the range of x-ray energies for which maximum attenuation contrast is expected in the polychromatic x-ray imaging system. In order to develop this predictive tool, a model has been constructed for the Bremsstrahlung spectrum of an x-ray tube, and calculations for the detector's efficiency over the relevant range of x-ray energies have been made, and the product of emitted and detected spectra has been used to calculate the effective x-ray imaging spectrum. An approach has also been established for filtering 'zinger' noise in x-ray radiographs, which has proven problematic at high x-ray energies used for solder imaging. The performance of this filter has been compared with a known existing method and the results indicate a significant increase in the accuracy of zinger filtered radiographs. The obtained results indicate the conception of a powerful means for the study of failure causing processes in solder systems used as interconnects in microelectronic packaging devices. These results include the

  17. 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.

  18. Comparison of the mechanical solidity of soldered and differently laser welded test specimens from a Palladium based alloy before and after six months of chemical stress.

    OpenAIRE

    Heintzenberg, Katja Ulrike

    2010-01-01

    The submitted study is about the comparison of the mechanical solidity of soldered and differently laser welded test specimens from a Palladium based alloy before and after six months of chemical stress. By vacuum-pressure-technique 80 DIN meeting test specimens have been produced from the Palladium alloy BegoPal® 300. 3 of the 10 series originated from five times cast reused metal, the remaining from pure new metal. After visual check of the test specimen...

  19. Experimental and computational study of the morphological evolution of intermetallic compound (Cu6Sn5) layers at the Cu/Sn interface under isothermal soldering conditions

    International Nuclear Information System (INIS)

    Park, M.S.; Stephenson, M.K.; Shannon, C.; Cáceres Díaz, L.A.; Hudspeth, K.A.; Gibbons, S.L.; Muñoz-Saldaña, J.; Arróyave, R.

    2012-01-01

    Cu/Sn soldering alloys have emerged as a viable alternative to Pb-based solders, and thus have been extensively explored in the past decade, although the fine-scale behavior of the resulting intermetallic compounds (IMCs), particularly during the early stages of interface formation, is still a source of debate. In this work, the microstructural evolution of Cu 6 Sn 5 , in a Cu/Sn soldering reaction at 523 K, was experimentally investigated by dipping a single Cu sample into molten Sn at a near-constant speed, yielding a continuous set of time evolution samples. The thickness, coarsening and morphology evolution of the Cu 6 Sn 5 layer is investigated through the use of scanning electron microscopy. The experimental results are also compared to phase-field simulations of the microstructural evolution of the Cu 6 Sn 5 layer. The influence of model parameters on the kinetics and morphological evolution of the IMC layer was examined. In general, good qualitative agreement is found between experiments and simulations and for a limited parameter set there appears to be good quantitative agreement between the growth kinetics of the Cu 6 Sn 5 layer, the grain boundary (GB) effect on grain coarsening, and the substrate/IMC interface roughness evolution. Furthermore, the parametric investigations of the model suggests that good agreement between experiments and simulations is achieved when the dominant transport mechanism for the reacting elements (Cu and Sn) is GB diffusion.

  20. Surface Modifications of Dental Ceramic Implants with Different Glass Solder Matrices: In Vitro Analyses with Human Primary Osteoblasts and Epithelial Cells

    Science.gov (United States)

    Mick, Enrico

    2014-01-01

    Ceramic materials show excellent esthetic behavior, along with an absence of hypersensitivity, making them a possible alternative implant material in dental surgery. However, their surface properties enable only limited osseointegration compared to titanium implants. Within this study, a novel surface coating technique for enhanced osseointegration was investigated biologically and mechanically. Specimens of tetragonal zirconia polycrystal (TZP) and aluminum toughened zirconia (ATZ) were modified with glass solder matrices in two configurations which mainly consisted of SiO2, Al2O3, K2O, and Na2O. The influence on human osteoblastic and epithelial cell viability was examined by means of a WST-1 assay as well as live/dead staining. A C1CP-ELISA was carried out to verify procollagen type I production. Uncoated/sandblasted ceramic specimens and sandblasted titanium surfaces were investigated as a reference. Furthermore, mechanical investigations of bilaterally coated pellets were conducted with respect to surface roughness and adhesive strength of the different coatings. These tests could demonstrate a mechanically stable implant coating with glass solder matrices. The coated ceramic specimens show enhanced osteoblastic and partly epithelial viability and matrix production compared to the titanium control. Hence, the new glass solder matrix coating could improve bone cell growth as a prerequisite for enhanced osseointegration of ceramic implants. PMID:25295270

  1. High-Temperature Active Soldering of SiC Particle-Reinforced Al-MMC Using a Novel ZnAlGaMgTi Filler Metal

    Science.gov (United States)

    Chen, Biqiang; Zhang, Guifeng; Zhang, Linjie; Xu, Tingting

    2017-10-01

    In order to broaden the application of SiC particle-reinforced aluminum matrix composite in electronics packaging, newly developed ZnAlGaMgTi filler with a low melting point of 418-441 °C was utilized as filler metal for active soldering of aluminum matrix composites (70 vol.%, SiCp/Al-MMCs) for the first time. The effect of loading pressure on joint properties of ZnAlGaMgTi active filler was investigated. The experimental results indicated that novel filler could successfully solder Al-MMCs, and the presence of Mg in the filler enhanced the penetration of Zn, while the forming of Zn-rich barrier layer influenced the active element MPD (melting point depressant) diffusion into parent composite, and the bulk-like (Mg-Si)-rich phase and Ti-containing phase were readily observed at the interface and bond seam. With the increase in loading pressure, the runout phenomenon appeared more significant, and the filler foil thickness and the Zn penetration depth varied pronouncedly. Sound joints with maximum shear strength of 29.6 MPa were produced at 480 °C at 1 MPa, and the crack occurred adjacent to the boundary of SiC particle and then propagated along the interface. A novel model describing the significant mutual diffusion of Al and Zn atoms between the parent material and solder was proposed.

  2. Interfacial Reaction and Mechanical Characterization of Sn-Ag-Cu/Au/Pd(P)/Cu Solder Joints: Thick Pd(P) Deposition

    Science.gov (United States)

    Ho, C. E.; Hsieh, W. Z.; Yang, C. H.; Yeh, T. C.; Kuo, T. T.

    2015-01-01

    The solderability of an Au/Pd(P)/Cu trilayer structure (thickness 0.15 μm/0.6-1.0 μm/20 μm) was investigated by use of a scanning electron microscope equipped with an electron backscatter diffraction system, electron probe microanalysis, and high-speed ball shear (HSBS) testing. Thick Pd(P) deposition, particularly the structure with a Pd(P) thickness of 1.0 μm, resulted in a substantial amount of (Pd,Cu)Sn4 intermetallic compound in the solder matrix after reflow. This phase gradually resettled at the interface and formed a dense layer of (Pd,Cu)Sn4 over (Cu,Pd)6Sn5 during solid-state reaction. A Cu-Pd-Sn isotherm was examined to explain the formation and resettlement of (Pd,Cu)Sn4. The (Pd,Cu)Sn4/(Cu,Pd)6Sn5 dual layer at the interface was a crack initiation site in HSBS testing, and led to substantial degradation of the mechanical strength of solder joints, indicating that thick Pd(P) deposition should be avoided to prevent the Pd-induced embrittlement.

  3. Complications with computer-aided designed/computer-assisted manufactured titanium and soldered gold bars for mandibular implant-overdentures: short-term observations.

    Science.gov (United States)

    Katsoulis, Joannis; Wälchli, Julia; Kobel, Simone; Gholami, Hadi; Mericske-Stern, Regina

    2015-01-01

    Implant-overdentures supported by rigid bars provide stability in the edentulous atrophic mandible. However, fractures of solder joints and matrices, and loosening of screws and matrices were observed with soldered gold bars (G-bars). Computer-aided designed/computer-assisted manufactured (CAD/CAM) titanium bars (Ti-bars) may reduce technical complications due to enhanced material quality. To compare prosthetic-technical maintenance service of mandibular implant-overdentures supported by CAD/CAM Ti-bar and soldered G-bar. Edentulous patients were consecutively admitted for implant-prosthodontic treatment with a maxillary complete denture and a mandibular implant-overdenture connected to a rigid G-bar or Ti-bar. Maintenance service and problems with the implant-retention device complex and the prosthesis were recorded during minimally 3-4 years. Annual peri-implant crestal bone level changes (ΔBIC) were radiographically assessed. Data of 213 edentulous patients (mean age 68 ± 10 years), who had received a total of 477 tapered implants, were available. Ti-bar and G-bar comprised 101 and 112 patients with 231 and 246 implants, respectively. Ti-bar mostly exhibited distal bar extensions (96%) compared to 34% of G-bar (p service. These short-term observations support the hypothesis that CAD/CAM Ti-bars reduce technical complications. Fracture location indicated that the titanium thickness around the screw-access hole should be increased. © 2013 Wiley Periodicals, Inc.

  4. Surface modifications of dental ceramic implants with different glass solder matrices: in vitro analyses with human primary osteoblasts and epithelial cells.

    Science.gov (United States)

    Markhoff, Jana; Mick, Enrico; Mitrovic, Aurica; Pasold, Juliane; Wegner, Katharina; Bader, Rainer

    2014-01-01

    Ceramic materials show excellent esthetic behavior, along with an absence of hypersensitivity, making them a possible alternative implant material in dental surgery. However, their surface properties enable only limited osseointegration compared to titanium implants. Within this study, a novel surface coating technique for enhanced osseointegration was investigated biologically and mechanically. Specimens of tetragonal zirconia polycrystal (TZP) and aluminum toughened zirconia (ATZ) were modified with glass solder matrices in two configurations which mainly consisted of SiO2, Al2O3, K2O, and Na2O. The influence on human osteoblastic and epithelial cell viability was examined by means of a WST-1 assay as well as live/dead staining. A C1CP-ELISA was carried out to verify procollagen type I production. Uncoated/sandblasted ceramic specimens and sandblasted titanium surfaces were investigated as a reference. Furthermore, mechanical investigations of bilaterally coated pellets were conducted with respect to surface roughness and adhesive strength of the different coatings. These tests could demonstrate a mechanically stable implant coating with glass solder matrices. The coated ceramic specimens show enhanced osteoblastic and partly epithelial viability and matrix production compared to the titanium control. Hence, the new glass solder matrix coating could improve bone cell growth as a prerequisite for enhanced osseointegration of ceramic implants.

  5. Surface Modifications of Dental Ceramic Implants with Different Glass Solder Matrices: In Vitro Analyses with Human Primary Osteoblasts and Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Jana Markhoff

    2014-01-01

    Full Text Available Ceramic materials show excellent esthetic behavior, along with an absence of hypersensitivity, making them a possible alternative implant material in dental surgery. However, their surface properties enable only limited osseointegration compared to titanium implants. Within this study, a novel surface coating technique for enhanced osseointegration was investigated biologically and mechanically. Specimens of tetragonal zirconia polycrystal (TZP and aluminum toughened zirconia (ATZ were modified with glass solder matrices in two configurations which mainly consisted of SiO2, Al2O3, K2O, and Na2O. The influence on human osteoblastic and epithelial cell viability was examined by means of a WST-1 assay as well as live/dead staining. A C1CP-ELISA was carried out to verify procollagen type I production. Uncoated/sandblasted ceramic specimens and sandblasted titanium surfaces were investigated as a reference. Furthermore, mechanical investigations of bilaterally coated pellets were conducted with respect to surface roughness and adhesive strength of the different coatings. These tests could demonstrate a mechanically stable implant coating with glass solder matrices. The coated ceramic specimens show enhanced osteoblastic and partly epithelial viability and matrix production compared to the titanium control. Hence, the new glass solder matrix coating could improve bone cell growth as a prerequisite for enhanced osseointegration of ceramic implants.

  6. Aeroflex Technology as Class-Y Demonstrator

    Science.gov (United States)

    Suh, Jong-ook; Agarwal, Shri; Popelar, Scott

    2014-01-01

    Modern space field programmable gate array (FPGA) devices with increased functional density and operational frequency, such as Xilinx Virtex 4 (V4) and S (V5), are packaged in non-hermetic ceramic flip chip forms. These next generation space parts were not qualified to the MIL-PRF-38535 Qualified Manufacturer Listing (QML) class-V when they were released because class-V was only intended for hermetic parts. In order to bring Xilinx V5 type packages into the QML system, it was suggested that class-Y be set up as a new category. From 2010 through 2014, a JEDEC G12 task group developed screening and qualification requirements for Class-Y products. The Document Standardization Division of the Defense Logistics Agency (DLA) has completed an engineering practice study. In parallel with the class-Y efforts, the NASA Electronic Parts and Packaging (NEPP) program has funded JPL to study potential reliability issues of the class-Y products. The major hurdle of this task was the absence of adequate research samples. Figure 1-1 shows schematic diagrams of typical structures of class-Y type products. Typically, class-Y products are either in ceramic flip chip column grid array (CGA) or land grid array (LGA) form. In class-Y packages, underfill and heat spread adhesive materials are directly exposed to the spacecraft environment due to their non-hermeticity. One of the concerns originally raised was that the underfill material could degrade due to the spacecraft environment and negatively impact the reliability of the package. In order to study such issues, it was necessary to use ceramic daisy chain flip chip package samples so that continuity of flip chip solder bumps could be monitored during the reliability tests. However, none of the commercially available class-Y daisy chain parts had electrical connections through flip chip solder bumps; only solder columns were daisy chained, which made it impossible to test continuity of flip chip solder bumps without using extremely

  7. Molten-Metal Droplet Deposition on a Moving Substrate in Microgravity: Aiding the Development of Novel Technologies for Microelectronic Assembly

    Science.gov (United States)

    Megaridis, C. M.; Bayer, I. S.; Poulikakos, D.; Nayagam, V.

    2002-01-01

    Driven by advancements in microelectronics manufacturing, this research investigates the oblique (non-axisymmetric) impact of liquid-metal droplets on flat substrates. The problem of interest is relevant to the development of the novel technology of on-demand dispension (printing) of microscopic solder deposits for the surface mounting of microelectronic devices. The technology, known as solder jetting, features on-demand deposition of miniature solder droplets (30 to 120 microns in diameter) in very fine, very accurate patterns using techniques analogous to those developed for the ink-jet printing industry. Despite its promise, severe limitations exist currently with regards to the throughput rates of the technology; some of these limitations are largely due to the lack of the capability for reliable prediction of solder bump positioning and shapes, especially under ballistic deposition conditions where the droplet impact phenomena are inherently three-dimensional. The study consists of a theoretical and an experimental component. The theoretical work uses a finite element formulation to simulate numerically the non-axisymmetric (3-D) fluid mechanics and heat transfer phenomena of a liquid solder droplet impacting at an angle alpha on a flat substrate. The work focuses on the pre-solidification regime. The modeling of the most challenging fluid mechanics part of the process has been completed successfully. It is based upon the full laminar Navier-Stokes equations employing a Lagrangian frame of reference. Due to the large droplet deformation, the surface (skin) as well as the volumetric mesh have to be regenerated during the calculations in order to maintain the high accuracy of the numerical scheme. The pressure and velocity fields are then interpolated on the newly created mesh. The numerical predictions are being tested against experiments, for cases where wetting phenomena are not important. For the impact parameters used in the example shown (We = 2.38, Fr

  8. Effect of additives on the co-electrodeposition of Sn-Ag-Cu lead-free solder composition

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Shany, E-mail: shany@cmet.gov.i [Electronic Packaging Group, Centre for Materials for Electronic Technology (C-MET), Panchawati, off Pashan Road, Pune-411 008 (India); Phatak, Girish J. [Electronic Packaging Group, Centre for Materials for Electronic Technology (C-MET), Panchawati, off Pashan Road, Pune-411 008 (India)

    2010-04-15

    We have developed a methane sulfonic acid (MSA) based ternary electrodeposition bath for the deposition of near eutectic Sn-Ag-Cu films aimed at solder bumping applications in electronics. The bath contains thiourea as chelating agent and iso-octyl phenoxy ethanol (OPPE) as surfactant. We added gelatin to this bath and studied its effect on bath stability, microstructure of the deposited films and the film composition. It is found that the bath containing both the additives, viz. OPPE and gelatin, show improved stability up to 8-10 days. Striking improvement in the film microstructure, in terms of the compactness, uniformity and refinement of grains was found when the bath contained these additives. Detailed electrochemical studies with the help of cyclic voltametry and impedance analysis helped in understanding the role played by these additives during deposition. It is confirmed that there is a formation of loosely connected, highly non-uniform passivating film on the cathode surface, which is removed competitively by the depositing metal ions during the deposition. It is also clear that the additives play a role in the formation of such a passivating film.

  9. 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.

  10. 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.

  11. Microstructural Aspects of Fatigue Parameters of Lead-Free Sn-Zn Solders with Various Zn Content

    Directory of Open Access Journals (Sweden)

    Pietrzak K.

    2017-03-01

    Full Text Available The study includes the results of research conducted on selected lead-free binary solder alloys designed for operation at high temperatures. The results of qualitative and quantitative metallographic examinations of SnZn alloys with various Zn content are presented. The quantitative microstructure analysis was carried out using a combinatorial method based on phase quanta theory, per which any microstructure can be treated as an array of elements disposed in the matrix material. Fatigue tests were also performed using the capabilities of a modified version of the LCF method hereinafter referred to in short as MLCF, which is particularly useful in the estimation of mechanical parameters when there are difficulties in obtaining many samples normally required for the LCF test. The fatigue life of alloys was analyzed in the context of their microstructure. It has been shown that the mechanical properties are improved with the Zn content increasing in the alloy. However, the best properties were obtained in the alloy with a chemical composition close to the eutectic system, when the Zn-rich precipitates showed the most preferred morphological characteristics. At higher content of Zn, a strong structural notch was formed in the alloy because of the formation in the microstructure of a large amount of the needle-like Zn-rich precipitates deteriorating the mechanical characteristics. Thus, the results obtained during previous own studies, which in the field of mechanical testing were based on static tensile test only, have been confirmed. It is interesting to note that during fatigue testing, both significant strengthening and weakening of the examined material can be expected. The results of fatigue tests performed on SnZn alloys have proved that in this case the material was softened.

  12. Facilitating NASA's Use of GEIA-STD-0005-1, Performance Standard for Aerospace and High Performance Electronic Systems Containing Lead-Free Solder

    Science.gov (United States)

    Plante, Jeannete

    2010-01-01

    GEIA-STD-0005-1 defines the objectives of, and requirements for, documenting processes that assure customers and regulatory agencies that AHP electronic systems containing lead-free solder, piece parts, and boards will satisfy the applicable requirements for performance, reliability, airworthiness, safety, and certify-ability throughout the specified life of performance. It communicates requirements for a Lead-Free Control Plan (LFCP) to assist suppliers in the development of their own Plans. The Plan documents the Plan Owner's (supplier's) processes, that assure their customer, and all other stakeholders that the Plan owner's products will continue to meet their requirements. The presentation reviews quality assurance requirements traceability and LFCP template instructions.

  13. 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

  14. The Wetting Properties of UBM-coated Si-wafer to the Lead-free Solders in Si-wafer/Bumps/Glass Flip-Chip Bonding System

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S.M.; Park, J.Y. [Seoul National University, Seoul (Korea); Park, C.B.; Jung, J.P. [University of Seoul, Seoul (Korea); Kang, C.S. [Seoul National University, Seoul (Korea)

    2000-04-24

    In an attempt to estimate the wetting properties of wettable metal layers by wetting balance method, an analysis of wetting curves of the coating later was performed. Based on the analysis, wetting properties of UBM-coated Si-plate were estimated by the new wettability indices. The wetting curves of the one and both sides-coated UBM layers have the similar shape and show the similar tendency to the temperature. So the wetting property estimation of one side coating is possible with wetting balance method. For UBM of Si-chip, Cr/Cu/Au UBM is better than Ti/Ni/Au in the point of wetting time. At general reflow temperature, the wettability of high melting point solders (Sn-Sb, Sn-Ag) is better than that of low melting point ones (Sn-Bi, Sn-In). The contact angle of the one side coated plate to the solder can be calculated from the force balance equation by measuring the static state force and the tilt angle. (author). 4 refs., 2 tabs., 9 figs.

  15. An in vitro toxicity evaluation of gold-, PLLA- and PCL-coated silica nanoparticles in neuronal cells for nanoparticle-assisted laser-tissue soldering.

    Science.gov (United States)

    Koch, Franziska; Möller, Anja-M; Frenz, Martin; Pieles, Uwe; Kuehni-Boghenbor, Kathrin; Mevissen, Meike

    2014-08-01

    The uptake of silica (Si) and gold (Au) nanoparticles (NPs) engineered for laser-tissue soldering in the brain was investigated using microglial cells and undifferentiated and differentiated SH-SY5Y cells. It is not known what effects NPs elicit once entering the brain. Cellular uptake, cytotoxicity, apoptosis, and the potential induction of oxidative stress by means of depletion of glutathione levels were determined after NP exposure at concentrations of 10(3) and 10(9)NPs/ml. Au-, silica poly (ε-caprolactone) (Si-PCL-) and silica poly-L-lactide (Si-PLLA)-NPs were taken up by all cells investigated. Aggregates and single NPs were found in membrane-surrounded vacuoles and the cytoplasm, but not in the nucleus. Both NP concentrations investigated did not result in cytotoxicity or apoptosis, but reduced glutathione (GSH) levels predominantly at 6 and 24h, but not after 12 h of NP exposure in the microglial cells. NP exposure-induced GSH depletion was concentration-dependent in both cell lines. Si-PCL-NPs induced the strongest effect of GSH depletion followed by Si-PLLA-NPs and Au-NPs. NP size seems to be an important characteristic for this effect. Overall, Au-NPs are most promising for laser-assisted vascular soldering in the brain. Further studies are necessary to further evaluate possible effects of these NPs in neuronal cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Quantitative analysis of trace lead in tin-base lead-free solder by laser-induced plasma spectroscopy in air at atmospheric pressure.

    Science.gov (United States)

    Chen, Baozhong; Kano, Hidenori; Kuzuya, Mikio

    2008-02-01

    A quantitative analysis of trace lead in tin-base lead-free solder was carried out with laser-induced plasma spectroscopy (LIPS). In order to evaluate the applicability of the technique for rapid in situ analytical purposes, measurements were performed in air at atmospheric pressure, and the emission characteristics of the plasma produced by a Q-switched Nd:YAG laser over a laser energy range of 10 - 90 mJ were investigated using time-resolved spectroscopy. The experimental results showed that the emission intensity of the analysis line (Pb I 405.78 nm) was maximized at a laser energy of around 30 mJ, and a time-resolved measurement of a spectrum with a delay time of 0.4 micros after the laser pulse was effective for reducing the background continuum. Based on the results, lead-free solder certified reference materials were analyzed for trace lead (concentration 174 - 1940 ppm), and a linear calibration curve was obtained with a detection limit of several tens ppm.

  17. Explorative study into the sustainable use and substitution of soldering metals in electronics : Ecological and economical consequences of the ban of lead in electronics and lessons to be learned for the future

    NARCIS (Netherlands)

    Deubzer, O.

    2007-01-01

    The Directive 2002/95/EC (RoHS Directive), among other substances, bans the use of lead in the electrical and electronics industry. This explorative study assesses the worldwide environmental and economical effects of the substitution of lead in solders and finishes. It shows the worldwide

  18. Investigation of electrochemical migration on Sn-0.7Cu-0.3Ag-0.03P-0.005Ni solder alloy in HNO{sub 3} solution

    Energy Technology Data Exchange (ETDEWEB)

    Sarveswaran, C.; Othman, N. K. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor (Malaysia); Ali, M. Yusuf Tura; Ani, F. Che; Samsudin, Z. [Jabil Circuit Sdn Bhd, Bayan Lepas Industrial Park, 11900, Penang (Malaysia)

    2015-09-25

    Current issue in lead-free solder in term of its reliability is still under investigation. This high impact research attempts to investigate the electrochemical migration (ECM) on Sn-0.7Cu-0.3Ag-0.03P-0.005Ni solder alloy by Water Drop Test (WDT) in different concentration of HNO{sub 3} solution. The concentration of HNO{sub 3} solution used in this research was 0.05, 0.10, 0.50 and 1M. Optical Microscope (OM), Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray Analysis (EDX) were carried out in order to analysis the ECM behavior based on the growth of dendrite formation after WDT. In general, the results demonstrated that dendrite growth is faster in higher concentration compared with low concentration of HNO{sub 3}. The concentration of HNO{sub 3} solution used has a strong correlation with Mean-Time-To-Failure (MTTF). As the concentration of HNO{sub 3} increases, the MTTF value decreases. Based on the MTTF results the solder alloy in 1M HNO{sub 3} solution is most susceptible to ECM. SnO{sub 2} forms as a corrosion by-product in the samples proved by EDX analysis. The solder alloy poses a high reliability risk in microelectronic devices during operation in 1M HNO{sub 3} solution.

  19. Effect of Isothermal Aging on the Long-Term Reliability of Fine-Pitch Sn-Ag-Cu and Sn-Ag Solder Interconnects With and Without Board-Side Ni Surface Finish

    Science.gov (United States)

    Lee, Tae-Kyu; Duh, Jeng-Gong

    2014-11-01

    The combined effects on long-term reliability of isothermal aging and chemically balanced or unbalanced surface finish have been investigated for fine-pitch ball grid array packages with Sn-3.0Ag-0.5Cu (SAC305) (wt.%) and Sn-3.5Ag (SnAg) (wt.%) solder ball interconnects. Two different printed circuit board surface finishes were selected to compare the effects of chemically balanced and unbalanced structure interconnects with and without board-side Ni surface finish. NiAu/solder/Cu and NiAu/solder/NiAu interconnects were isothermally aged and thermally cycled to evaluate long-term thermal fatigue reliability. Weibull plots of the combined effects of each aging condition and each surface finish revealed lifetime for NiAu/SAC305/Cu was reduced by approximately 40% by aging at 150°C; less degradation was observed for NiAu/SAC305/NiAu. Further reduction of characteristic life-cycle number was observed for NiAu/SnAg/NiAu joints. Microstructure was studied, focusing on its evolution near the board and package-side interfaces. Different mechanisms of aging were apparent under the different joint configurations. Their effects on the fatigue life of solder joints are discussed.

  20. Silver flip chip interconnect technology and solid state bonding

    Science.gov (United States)

    Sha, Chu-Hsuan

    -section, there is no void or gap observed. The new bonding technique presented should be valuable in packaging high power electronic devices for high temperature operations. It should also be useful to bond two 304SS parts together at low bonding temperature of 190ºC. Solid state bonding technique is then introduced to bond semiconductor chips, such as Si, to common substrates, such as Cu or alumina, using pure Ag and Au at a temperature matching the typical reflow temperature used in packaging industries, 260°C. In bonding, we realize the possibilities of solid state bonding of Au to Au, Au to Ag, and Ag to Cu. The idea comes from that Cu, Ag, and Au are located in the same column on periodic table, meaning that they have similar electronic configuration. They therefore have a better chance to share electrons. Also, the crystal lattice of Cu, Ag, and Au is the same, face-centered cubic. In the project, the detailed bonding mechanism is beyond the scope and here we determine the bonding by the experimental result. Ag is chosen as the joint material because of its superior physical properties. It has the highest electrical and thermal conductivities among all metals. It has low yield strength and is relatively ductile. Au is considered as well because its excellent ductility and fatigue resistance. Thus, the Ag or Au joints can deform to accommodate the shear strain caused by CTE mismatch between Si and Cu. Ag and Au have melting temperatures higher than 950°C, so the pure Ag or Au joints are expected to sustain in high operating temperature. The resulting joints do not contain any intermetallic compound. Thus, all reliability issues associated with intermetallic growth in commonly used solder joints do not exist anymore. We finally move to the applications of solid state Ag bonding in flip chip interconnects design. At present, nearly all large-scale integrated circuit (IC) chips are packaged with flip-chip technology. This means that the chip is flipped over and the active

  1. Phase segregation, interfacial intermetallic growth and electromigration-induced failure in Cu/In–48Sn/Cu solder interconnects under current stressing

    International Nuclear Information System (INIS)

    Li, Yi; Lim, Adeline B.Y.; Luo, Kaiming; Chen, Zhong; Wu, Fengshun; Chan, Y.C.

    2016-01-01

    The evolution of microstructure in Cu/In–48Sn/Cu solder bump interconnects at a current density of 0.7 × 10 4 A/cm 2 and ambient temperature of 55 °C has been investigated. During electromigration, tin (Sn) atoms migrated from cathode to anode, while indium (In) atoms migrated from anode to cathode. As a result, the segregation of the Sn-rich phase and the In-rich phase occurred. A Sn-rich layer and an In-rich layer were formed at the anode and the cathode, respectively. The accumulation rate of the Sn-rich layer was 1.98 × 10 −9 cm/s. The atomic flux of Sn was calculated to be approximately 1.83 × 10 13 atoms/cm 2 s. The product of the diffusivity and the effective charge number of Sn was determined to be approximately 3.13 × 10 −10 cm 2 /s. The In–48Sn/Cu IMC showed a two layer structure of Cu 6 (Sn,In) 5 , adjacent to the Cu, and Cu(In,Sn) 2 , adjacent to the solder. Both the cathode IMC and the anode IMC thickened with increasing electromigration time. The IMC evolution during electromigration was strongly influenced by the migration of Cu atoms from cathode to anode and the accumulation of Sn-rich and In-rich layers. During electromigration, the Cu(In,Sn) 2 at the cathode interface thickened significantly, with a spalling characteristic, due to the accumulation of In-rich layer and the migration of Cu atoms - while the Cu(In,Sn) 2 at the anode interface reduced obviously, due to the accumulation of Sn-rich layer. The mechanism of electromigration-induced failure in Cu/In–48Sn/Cu interconnects was the cathode Cu dissolution-induced solder melt, which led to the rapid consumption of Cu in the cathode pad during liquid-state electromigration and this finally led to the failure. - Highlights: • Sn migrates to the anode, while In migrates to the cathode, during EM in Cu/In–48Sn/Cu. • The atomic flux of Sn has been calculated. • The interfacial IMCs were identified as: Cu 6 (Sn,In) 5 + Cu(In,Sn) 2 . • The interface evolution is strongly

  2. Uptake kinetics of the somatostatin receptor ligand [86Y]DOTA-dPhe1-Tyr3-octreotide ([86Y]SMT487) using positron emission tomography in non-human primates and calculation of radiation doses of the 90Y-labelled analogue

    International Nuclear Information System (INIS)

    Roesch, F.; Brockmann, J.; Koehle, M.

    1999-01-01

    [ 90 Y]DOTA-dPhe 1 -Tyr 3 -octreotide ([ 90 Y]-SMT487) has been suggested as a promising radiotherapeutic agent for somatostatin receptor-expressing tumours. In order to quantify the in vivo parameters of this compound and the radiation doses delivered to healthy organs, the analogue [ 86 Y]DOTA-dPhe 1 -Tyr 3 -octreotide was synthesised and its uptake measured in baboons using positron emission tomography (PET). [ 86 Y]DOTA-dPhe 1 -Tyr 3 -octreotide was administered at two different peptide concentrations, namely 2 and 100 μg peptide per m 2 body surface. The latter concentration corresponded to a radiotherapeutic dose. In a third protocol [ 86 Y]DOTA-dPhe 1 -Tyr 3 -octreotide was injected in conjunction with a simultaneous infusion of an amino acid solution that was high in l-lysine in order to lower the renal uptake of radioyttrium. Quantitative whole-body PET scans were recorded to measure the uptake kinetics for kidneys, liver, lung and bone. The individual absolute uptake kinetics were used to calculate the radiation doses for [ 90 Y]DOTA-dPhe 1 -Tyr 3 -octreotide according to the MIRD recommendations extrapolated to a 70-kg human. The highest radiation dose was received by the kidneys, with 2.1-3.3 mGy per MBq [ 90 Y]DOTA-dPhe 1 -Tyr 3 -octreotide injected. For the 100 μg/m 2 SMT487 protocol with amino acid co-infusion this dose was about 20%-40% lower than for the other two treatment protocols. The liver and the red bone marrow received doses ranging from 0.32 to 0.53 mGy and 0.03 to 0.07 mGy per MBq [ 90 Y]DOTA-dPhe 1 -Tyr 3 -octreotide, respectively. The average effective dose equivalent amounted to 0.23-0.32 mSv/MBq. The comparatively low estimated radiation doses to normal organs support the initiation of clinical phase I trials with [ 90 Y]DOTA-dPhe 1 -Tyr 3 -octreotide in patients with somatostatin receptor-expressing tumours. (orig.)

  3. In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

    2009-12-01

    Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the Beta-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of Beta-Sn derived from the electromigration data is in good agreement with the calculated value.

  4. In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

    2009-05-15

    Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the {beta}-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of {beta}-Sn derived from the electromigration data is in good agreement with the calculated value.

  5. Anisotropic viscoelastic shell modeling technique of copper patterns/photoimageable solder resist composite for warpage simulation of multi-layer printed circuit boards

    International Nuclear Information System (INIS)

    Kim, Do-Hyoung; Joo, Sung-Jun; Kim, Hak-Sung; Kwak, Dong-Ok

    2015-01-01

    In this study, the warpage simulation of a multi-layer printed circuit board (PCB) was performed as a function of various copper (Cu) patterns/photoimageable solder resist (PSR) composite patterns and their anisotropic viscoelastic properties. The thermo-mechanical properties of Cu/PSR patterns were obtained from finite element analysis (virtual test) and homogenized with anisotropic composite shell models that considered the viscoelastic properties. The multi-layer PCB model was simplified based on the unit Cu/PSR patterns and the warpage simulation during the reflow process was performed by using ABAQUS combined with a user-defined subroutine. From these results, it was demonstrated that the proposed anisotropic viscoelastic composite shell simulation technique can be successfully used to predict warpage of multi-layer PCBs during the reflow process. (paper)

  6. The use of a directional solidification technique to investigate the interrelationship of thermal parameters, microstructure and microhardness of Bi–Ag solder alloys

    International Nuclear Information System (INIS)

    Spinelli, José Eduardo; Silva, Bismarck Luiz; Cheung, Noé; Garcia, Amauri

    2014-01-01

    Bi–Ag alloys have been stressed as possible alternatives to replace Pb-based solder alloys. Although acceptable melting temperatures and suitable mechanical properties may characterize such alloys, as referenced in literature, there is a lack of comprehension regarding their microstructures (morphologies and sizes of the phases) considering a composition range from 1.5 to 4.0 wt.%Ag. In order to better comprehend such aspects and their correlations with solidification thermal parameters (growth rate, v and cooling rate, T-dot), directional solidification experiments were carried out under transient heat flow conditions. The effects of Ag content on both cooling rate and growth rate during solidification are examined. Microstructure parameters such as eutectic/dendritic spacing, interphase spacing and diameter of the Ag-rich phase were determined by optical microscopy and scanning electron microscopy. The competition between eutectic cells and dendrites in the range from 1.5 to 4.0 wt.%Ag is explained by the coupled zone concept. Microhardness was determined for different microstructures and alloy Ag contents with a view to permitting correlations with microstructure parameters to be established. Hardness is shown to be directly affected by both solute macrosegregation and morphologies of the phases forming the Bi–Ag alloys, with higher hardness being associated with the cellular morphology of the Bi-2.5 and 4.0 wt.%Ag alloys. - Highlights: • Asymmetric zone of coupled growth for Bi–Ag is demonstrated. • Faceted Bi-rich dendrites have been characterized for Bi–1.5 wt.%Ag alloy. • Eutectic cells were shown for the Bi-2.5 and 4.0 wt.%Ag solder alloys. • Interphase spacing relations with G × v are able to represent the experimental scatters. • Hall-Petch type equations are proposed relating microstructural spacings to hardness

  7. Self service, self-unloading vessels and technology

    Energy Technology Data Exchange (ETDEWEB)

    Venter, J.

    2007-02-15

    Latest developments are reported in design of and contracts for grabs and self-unloading vessels from the following companies: Eitzen Bulk, Beco Bleijenberg, MacGregor Bulk, Naftotrade Group, and Seaway Marine Transport (SMT). 7 photos.

  8. Effect of the bismuth content on the interface reactions between copper substrate and Sn-Zn-Al-Bi lead-free solder

    Directory of Open Access Journals (Sweden)

    Soares, D.

    2005-12-01

    Full Text Available Because of environmental and health concerns, some alternative solder alloys, named lead-free ones, are being developed. Among them, the Sn-Zn-Al system has been studied and reveals promising properties. In this work the presence of bismuth, in the range of 0-8 wt%, was evaluated in what concerns to the chemical interactions between solder/substrate and the equilibrium phases present at the interface. The phases formed at the interface between the copper substrate and a molten lead-free solder were studied with different time of stage and alloy compositions. The effect of bismuth content on transformation temperatures of a Sn-9Zn-1Al base alloy was studied by Differential Scanning Calorimetry (DSC. For each alloy the solidification range was determined, which is an important characteristic regarding the application of these materials in the electronic industry. Identification of equilibrium phases and their chemical composition evaluation was performed by scanning electron microscopy (SEM/EDS. The interface thickness and chemical composition profiles were also evaluated.

    Debido a las preocupaciones ambientales y sanitarias, se están desarrollando aleaciones alternativas para soldadura sin plomo. Entre ellas se ha estudiado el sistema Sn-Zn-Al, que revela propiedades prometedoras. En este trabajo se evalúa la presencia de bismuto, en el rango de 0 a 8 % en peso, en relación con las interacciones químicas entre soldadura y substrato y con las fases de equilibrio presentes en la superficie de contacto. Se han estudiado las fases formadas en la superficie de contacto entre el substrato de cobre y una soldadura fundida sin plomo en función del tiempo de mantenimiento y de la composición de la aleación. Se ha evaluado el efecto del contenido en bismuto sobre las temperaturas de transformación de una aleación de base Sn-9Zn-1Al mediante Calorimetría de Barrido Diferencial (DSC. Se ha determinado el rango de solidificación para cada

  9. 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.

  10. The handling of thin substrates and its potential for new architectures in multi-junction solar cells technology

    Science.gov (United States)

    Colin, Clément; Jaouad, Abdelatif; Darnon, Maxime; De Lafontaine, Mathieu; Volatier, Maïté; Boucherif, Abderraouf; Arès, Richard; Fafard, Simon; Aimez, Vincent

    2017-09-01

    In this paper, we investigate the development of a robust handling process for thin (monolithic multi-junction solar cell (MJSC) technology. The process, designed for its versatility, is based on a temporary front side bonding of the cell with a polymeric adhesive and then a permanent back side soldering, allowing classical cell micro-fabrication steps on both sides of the wafer. We have demonstrated that the process does not degrade the performances of monolithic MJSC with Ge substrates thickness reduced from 170 µm to 25 µm. Then, we investigate a perspective unlocked with this work: the study of 3D-interconnect architecture for multi-junction solar cells.

  11. Corrosion Damage Investigation of Silver-Soldered Stainless Steel Orthodontic Appliances Used in Vivo / Ocena Zniszczeń Korozyjnych Używanych In Vivo Stałych Aparatów Ortodontycznych O Połączeniach Lutowanych Na Bazie Srebra

    Directory of Open Access Journals (Sweden)

    Łępicka M.

    2015-12-01

    Full Text Available Processes of destruction of products used in orthodontic treatment, e.g. fixed orthodontic appliances, microimplants or dental prostheses considerably limit its operational lifetime and comfort and safety of patients. The objective of the research was to evaluate and assess corrosion damage to silver-soldered stainless steel rapid palatal expansion Hyrax devices. Used in vivo for 2 or 6 months, respectively, RPE (rapid palatal expansion devices were analyzed macroscopically and in a scanning electron microscope with an energy X-ray analyzer for signs of corrosion. The evaluated appliances showed discernible differences between the overall condition of the noble solders and the stainless steel elements. The Ag-rich solders were chiefly covered in corrosion pits, whereas stainless steel wires, molar bands and Hyrax screws presented corrosion-free surfaces. What is more, the EDS analysis showed differential element composition of the solders. According to the results, noble materials, such as Ag-rich solders, can corrode in a salivary environment when coupled with stainless steel. The selective leaching processes are observed.

  12. SMT-Based Formal Verification of a TTEthernet Synchronization Function

    Science.gov (United States)

    Steiner, Wilfried; Dutertre, Bruno

    TTEthernet is a communication infrastructure for mixed-criticality systems that integrates dataflow from applications with different criticality levels on a single network. For applications of highest criticality, TTEthernet provides a synchronization strategy that tolerates multiple failures. The resulting fault-tolerant timebase can then be used for time-triggered communication to ensure temporal partitioning on the shared network.

  13. Systematics of Structural, Phase Stability, and Cohesive Properties of η'-Cu6(Sn,In)5 Compounds Occurring in In-Sn/Cu Solder Joints

    Science.gov (United States)

    Ramos, S. B.; González Lemus, N. V.; Deluque Toro, C. E.; Cabeza, G. F.; Fernández Guillermet, A.

    2017-07-01

    Motivated by the high solubility of In in ( mC44) η'-Cu6Sn5 compound as well as the occurrence of an In-doped η'-intermetallic in the microstructure of Cu/In-Sn/Cu solder joints, a theoretical study has been carried out to investigate the various physical effects of incorporating In at Sn Wyckoff sites of the binary η'-phase. Systematic ab initio calculations using the projected augmented wave method and Vienna Ab initio Simulation Package were used to determine the composition dependence of the structural and cohesive properties of η'-Cu6(Sn,In)5 compounds, compared with those expected from the binary end-member compounds Cu6Sn5 and Cu6In5. The molar volume shows significant deviations from Vegard's law. The predicted composition dependence of the cohesive properties is discussed using two complementary approaches, viz. a valence-electron density approach as well as a bond-number approach, both accounting for the roughly linear dependence of the cohesive energy on the In content. A microscopic interpretation for this general trend is given in terms of the key contributions to chemical bonding in this class of compounds, namely Cu d-electron overlap and hybridization of Cu d-states with In and Sn p-electron states. Moreover, a crystallographic site approach is developed to accurately establish the phase-stabilizing effect of incorporating In at specific Wyckoff positions of the ( mC44) η'-Cu6Sn5 structure.

  14. Laser Technology.

    Science.gov (United States)

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  15. 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.

  16. Pull strength evaluation of Sn-Pb solder joints made to Au-Pt-Pd and Au thick film structures on low-temperature co-fired ceramic -final report for the MC4652 crypto-coded switch (W80).

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, Fernando; Vianco, Paul Thomas; Zender, Gary L.

    2006-06-01

    A study was performed that examined the microstructure and mechanical properties of 63Sn-37Pb (wt.%, Sn-Pb) solder joints made to thick film layers on low-temperature co-fired (LTCC) substrates. The thick film layers were combinations of the Dupont{trademark} 4596 (Au-Pt-Pd) conductor and Dupont{trademark} 5742 (Au) conductor, the latter having been deposited between the 4596 layer and LTCC substrate. Single (1x) and triple (3x) thicknesses of the 4596 layer were evaluated. Three footprint sizes were evaluated of the 5742 thick film. The solder joints exhibited excellent solderability of both the copper (Cu) lead and thick film surface. In all test sample configurations, the 5742 thick film prevented side wall cracking of the vias. The pull strengths were in the range of 3.4-4.0 lbs, which were only slightly lower than historical values for alumina (Al{sub 2}O{sub 3}) substrates. General (qualitative) observations: (a) The pull strength was maximized when the total number of thick film layers was between two and three. Fewer that two layers did not develop as strong of a bond at the thick film/LTCC interface; more than three layers and of increased footprint area, developed higher residual stresses at the thick film/LTCC interface and in the underlying LTCC material that weakened the joint. (b) Minimizing the area of the weaker 4596/LTCC interface (e.g., larger 5742 area) improved pull strength. Specific observations: (a) In the presence of vias and the need for the 3x 4596 thick film, the preferred 4596:5742 ratio was 1.0:0.5. (b) For those LTCC components that require the 3x 4596 layer, but do not have vias, it is preferred to refrain from using the 5742 layer. (c) In the absence of vias, the highest strength was realized with a 1x thick 5742 layer, a 1x thick 4596 layer, and a footprint ratio of 1.0:1.0.

  17. Taming Technology

    Science.gov (United States)

    Branscomb, Lewis M.

    1971-01-01

    Reviews aspects of technology in our society: technology as a force for social change; reasons for the frustration and dissatisfaction with technology; how technology decentralizes power; the individual's influence; resolving conflicts in the ionized" society; regulation of technology; corporate responsibility; and the potential pitfalls for the…

  18. Assistive Technology

    Science.gov (United States)

    ... Page Resize Text Printer Friendly Online Chat Assistive Technology Assistive technology (AT) is any service or tool that helps ... be difficult or impossible. For older adults, such technology may be a walker to improve mobility or ...

  19. Sport Technology

    CSIR Research Space (South Africa)

    Kirkbride, T

    2007-11-01

    Full Text Available Technology is transforming the games themselves and at times with dire consequences. Tony Kirkbride, Head: CSIR Technology Centre said there are a variety of sports technologies and there have been advances in material sciences and advances...

  20. Rover Technologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop and mature rover technologies supporting robotic exploration including rover design, controlling rovers over time delay and for exploring . Technology...

  1. Nano technology

    International Nuclear Information System (INIS)

    Lee, In Sik

    2002-03-01

    This book is introduction of nano technology, which describes what nano technology is, alpha and omega of nano technology, the future of Korean nano technology and human being's future and nano technology. The contents of this book are nano period is coming, a engine of creation, what is molecular engineering, a huge nano technology, technique on making small things, nano materials with exorbitant possibility, the key of nano world the most desirable nano technology in bio industry, nano development plan of government, the direction of development for nano technology and children of heart.

  2. Technology developments for thrust chambers of future launch vehicle liquid rocket engines

    Science.gov (United States)

    Immich, H.; Alting, J.; Kretschmer, J.; Preclik, D.

    2003-08-01

    In this paper an overview of recent technology developments for thrust chambers of future launch vehicle liquid rocket engines at Astrium, Space Infrastructure Division (SI), is shown. The main technology. developments shown in this paper are: Technologies Technologies for enhanced heat transfer to the coolant for expander cycle engines Advanced injector head technologies Advanced combustion chamber manufacturing technologies. The main technologies for enhanced heat transfer investigated by subscale chamber hot-firing tests are: Increase of chamber length Hot gas side ribs in the chamber Artificially increased surface roughness. The developments for advanced injector head technologies were focused on the design of a new modular subscale chamber injector head. This injector head allows for an easy exchange of different injection elements: By this, cost effective hot-fire tests with different injection element concepts can be performed. The developments for advanced combustion chamber manufacturing technologies are based on subscale chamber tests with a new design of the Astrium subscale chamber. The subscale chamber has been modified by introduction of a segmented cooled cylindrical section which gives the possibility to test different manufacturing concepts for cooled chamber technologies by exchanging the individual segments. The main technology efforts versus advanced manufacturing technologies shown in this paper are: Soldering techniques Thermal barrier coatings for increased chamber life. A new technology effort is dedicated especially to LOX/Hydrocarbon propellant combinations. Recent hot fire tests on the subscale chamber with Kerosene and Methane as fuel have already been performed. A comprehensive engine system trade-off between the both propellant combinations (Kerosene vs. Methane) is presently under preparation.

  3. Information Technology

    Science.gov (United States)

    2003-01-01

    The first wave delivered a range of services to most areas of the world through a vast, carefully constructed global network. Cellular technology ...Information Technology and Services Alliance. Digital Planet 2002: The Global Information Economy. February 2002. Yegyazarian, Anush. Sales Taxes...Information Technology ABSTRACT: The information technology (IT) industry affects virtually every industry in the n economy. During the late 90

  4. Development of diffusion welded compact heat exchanger technology

    International Nuclear Information System (INIS)

    Mortean, M.V.V.; Cisterna, L.H.R.; Paiva, K.V.; Mantelli, M.B.H.

    2016-01-01

    Highlights: • Four new fabrication technologies for compact heat exchanger cores are presented. • The heat exchangers tested are fabricated by diffusion bonding process. • Results showed that cut-plate heat exchanger is the most promising technology. • Experimental results were compared favorably with numerical and analytical results. - Abstract: Compact heat exchangers are heat transfer equipment employed in applications where weight and volume are significantly relevant constraints, such as vehicles (automotive, maritime, avionics and space). The main characteristic of this equipment is the high heat transfer rate for small volumes. Only recently compact heat exchangers have received greater attention from the researchers, and therefore, manufacturing processes and mathematical modeling still demand development. The main objective of this work is to present and analyze four new fabrication technologies for compact heat exchanger cores, resulting in small cross sectional controlled geometry. Three of them consist of sandwiches of flat plates filled with: parallel circular wires, rectangular wires or rectangular tubes. The fourth consists of stacking flat plates interfiled with water jet machined plates. In all these procedures, stacks of metal layers are formed and diffusion bonding process is proposed for soldering. Copper prototypes were constructed to test the fabrication technologies. Results showed that stacking layers of machined comb-like plates interfiled with flat plates is the most promising fabrication technology, which was used to construct a copper prototype that was tested using water as both hot and cold fluids. The present technology was compared for both the volumetric power and the overall heat transfer coefficients with other heat exchangers, presenting an intermediate performance. Experimental results were compared favorably with numerical and analytical results from the literature.

  5. Electronic technology

    International Nuclear Information System (INIS)

    Kim, Jin Su

    2010-07-01

    This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

  6. Globalization & technology

    DEFF Research Database (Denmark)

    Narula, Rajneesh

    Technology and globalization are interdependent processes. Globalization has a fundamental influence on the creation and diffusion of technology, which, in turn, affects the interdependence of firms and locations. This volume examines the international aspect of this interdependence at two levels...

  7. Living Technology

    DEFF Research Database (Denmark)

    2010-01-01

    This book is aimed at anyone who is interested in learning more about living technology, whether coming from business, the government, policy centers, academia, or anywhere else. Its purpose is to help people to learn what living technology is, what it might develop into, and how it might impact...... our lives. The phrase 'living technology' was coined to refer to technology that is alive as well as technology that is useful because it shares the fundamental properties of living systems. In particular, the invention of this phrase was called for to describe the trend of our technology becoming...... increasingly life-like or literally alive. Still, the phrase has different interpretations depending on how one views what life is. This book presents nineteen perspectives on living technology. Taken together, the interviews convey the collective wisdom on living technology's power and promise, as well as its...

  8. Earthing Technology

    NARCIS (Netherlands)

    Blok, Vincent

    2017-01-01

    In this article, we reflect on the conditions under which new technologies emerge in the Anthropocene and raise the question of how to conceptualize sustainable technologies therein. To this end, we explore an eco-centric approach to technology development, called biomimicry. We discuss opposing

  9. Technology Tiers

    DEFF Research Database (Denmark)

    Karlsson, Christer

    2015-01-01

    A technology tier is a level in a product system: final product, system, subsystem, component, or part. As a concept, it contrasts traditional “vertical” special technologies (for example, mechanics and electronics) and focuses “horizontal” feature technologies such as product characteristics...

  10. Soulful Technologies

    DEFF Research Database (Denmark)

    Fausing, Bent

    2010-01-01

    or anthropomorphism is important for the branding of new technology. Technology is seen as creating a techno-transcendence towards a more qualified humanity which is in contact with fundamental human values like intuition, vision, and sensing; all the qualities that technology, industrialization, and rationalization......, - in short modernity - have taken away from human existence. What old technology has removed now comes back through new technology promoting a better humanity. The present article investigates how digital technology and affects are presented and combined, with examples from everyday imagery, e.g. TV......Samsung introduced in 2008 a mobile phone called "Soul" made with a human touch and including itself a "magic touch". Through the analysis of a Nokia mobile phone TV-commercials I want to examine the function and form of digital technology in everyday images. The mobile phone and its digital camera...

  11. International Symposium on Interfacial Joining and Surface Technology (IJST2013)

    Science.gov (United States)

    Takahashi, Yasuo

    2014-08-01

    Interfacial joining (bonding) is a widely accepted welding process and one of the environmentally benign technologies used in industrial production. As the bonding temperature is lower than the melting point of the parent materials, melting of the latter is kept to a minimum. The process can be based on diffusion bonding, pressure welding, friction welding, ultrasonic bonding, or brazing-soldering, all of which offer many advantages over fusion welding. In addition, surface technologies such as surface modification, spraying, coating, plating, and thin-film formation are necessary for advanced manufacturing, fabrication, and electronics packaging. Together, interfacial joining and surface technology (IJST) will continue to be used in various industrial fields because IJST is a very significant form of environmentally conscious materials processing. The international symposium of IJST 2013 was held at Icho Kaikan, Osaka University, Japan from 27-29 November, 2013. A total of 138 participants came from around the world to attend 56 oral presentations and 36 posters presented at the symposium, and to discuss the latest research and developments on interfacial joining and surface technologies. This symposium was also held to commemorate the 30th anniversary of the Technical Commission on Interfacial Joining of the Japan Welding Society. On behalf of the chair of the symposium, it is my great pleasure to present this volume of IOP Conference Series: Materials Science and Engineering (MSE). Among the presentations, 43 papers are published here, and I believe all of the papers have provided the welding community with much useful information. I would like to thank the authors for their enthusiastic and excellent contributions. Finally, I would like to thank all members of the committees, secretariats, participants, and everyone who contributed to this symposium through their support and invaluable effort for the success of IJST 2013. Yasuo Takahashi Chair of IJST 2013

  12. International Symposium on Interfacial Joining and Surface Technology (IJST2013)

    International Nuclear Information System (INIS)

    Takahashi, Yasuo

    2014-01-01

    Interfacial joining (bonding) is a widely accepted welding process and one of the environmentally benign technologies used in industrial production. As the bonding temperature is lower than the melting point of the parent materials, melting of the latter is kept to a minimum. The process can be based on diffusion bonding, pressure welding, friction welding, ultrasonic bonding, or brazing-soldering, all of which offer many advantages over fusion welding. In addition, surface technologies such as surface modification, spraying, coating, plating, and thin-film formation are necessary for advanced manufacturing, fabrication, and electronics packaging. Together, interfacial joining and surface technology (IJST) will continue to be used in various industrial fields because IJST is a very significant form of environmentally conscious materials processing. The international symposium of IJST 2013 was held at Icho Kaikan, Osaka University, Japan from 27–29 November, 2013. A total of 138 participants came from around the world to attend 56 oral presentations and 36 posters presented at the symposium, and to discuss the latest research and developments on interfacial joining and surface technologies. This symposium was also held to commemorate the 30th anniversary of the Technical Commission on Interfacial Joining of the Japan Welding Society. On behalf of the chair of the symposium, it is my great pleasure to present this volume of IOP Conference Series: Materials Science and Engineering (MSE). Among the presentations, 43 papers are published here, and I believe all of the papers have provided the welding community with much useful information. I would like to thank the authors for their enthusiastic and excellent contributions. Finally, I would like to thank all members of the committees, secretariats, participants, and everyone who contributed to this symposium through their support and invaluable effort for the success of IJST 2013. Yasuo Takahashi Chair of IJST 2013

  13. Technology '90

    International Nuclear Information System (INIS)

    1991-01-01

    The US Department of Energy (DOE) laboratories have a long history of excellence in performing research and development in a number of areas, including the basic sciences, applied-energy technology, and weapons-related technology. Although technology transfer has always been an element of DOE and laboratory activities, it has received increasing emphasis in recent years as US industrial competitiveness has eroded and efforts have increased to better utilize the research and development resources the laboratories provide. This document, Technology '90, is the latest in a series that is intended to communicate some of the many opportunities available for US industry and universities to work with the DOE and its laboratories in the vital activity of improving technology transfer to meet national needs. Technology '90 is divided into three sections: Overview, Technologies, and Laboratories. The Overview section describes the activities and accomplishments of the DOE research and development program offices. The Technologies section provides descriptions of new technologies developed at the DOE laboratories. The Laboratories section presents information on the missions, programs, and facilities of each laboratory, along with a name and telephone number of a technology transfer contact for additional information. Separate papers were prepared for appropriate sections of this report

  14. Sensemaking technologies

    DEFF Research Database (Denmark)

    Madsen, Charlotte Øland

    Research scope: The scope of the project is to study technological implementation processes by using Weick's sensemaking concept (Weick, 1995). The purpose of using a social constructivist approach to investigate technological implementation processes is to find out how new technologies transform...... patterns of social action and interaction in organisations (Barley 1986; 1990, Orlikowski 2000). Current research in the field shows that new technologies affect organisational routines/structures/social relationships/power relations/dependencies and alter organisational roles (Barley 1986; 1990, Burkhardt......, Orlikowski 2000). Viewing the use of technology as a process of enactment opens up for investigating the social processes of interpreting new technology into the organisation (Orlikowski 2000). The scope of the PhD project will therefore be to gain a deeper understanding of how the enactment of new...

  15. Technological risks

    International Nuclear Information System (INIS)

    Klinke, A.; Renn, O.

    1998-01-01

    The empirical part about the technological risks deals with different technologies: nuclear energy, early warning systems of nuclear weapons and NBC-weapons, and electromagnetic fields. The potential of damage, the contemporary management strategies and the relevant characteristics will be described for each technology: risks of nuclear energy; risks of early warning systems of nuclear weapons and NBC-weapons; risks of electromagnetic fields. (authors)

  16. Technological risks

    Energy Technology Data Exchange (ETDEWEB)

    Klinke, A.; Renn, O. [Center of Technology Assessment in Baden-Wuerttemberg, Stuttgart (Germany)

    1998-07-01

    The empirical part about the technological risks deals with different technologies: nuclear energy, early warning systems of nuclear weapons and NBC-weapons, and electromagnetic fields. The potential of damage, the contemporary management strategies and the relevant characteristics will be described for each technology: risks of nuclear energy; risks of early warning systems of nuclear weapons and NBC-weapons; risks of electromagnetic fields. (authors)

  17. Technology alliances

    International Nuclear Information System (INIS)

    Torgerson, D.F.; Boczar, P.G.; Kugler, G.

    1991-10-01

    In the field of nuclear technology, Canada and Korea developed a highly successful relationship that could serve as a model for other high-technology industries. This is particularly significant when one considers the complexity and technical depth required to design, build and operate a nuclear reactor. This paper will outline the overall framework for technology transfer and cooperation between Canada and Korea, and will focus on cooperation in nuclear R and D between the two countries

  18. Chemistry Technology

    Data.gov (United States)

    Federal Laboratory Consortium — Chemistry technology experts at NCATS engage in a variety of innovative translational research activities, including:Design of bioactive small molecules.Development...

  19. Technology Catalogue

    International Nuclear Information System (INIS)

    1994-02-01

    The Department of Energy's Office of Environmental Restoration and Waste Management (EM) is responsible for remediating its contaminated sites and managing its waste inventory in a safe and efficient manner. EM's Office of Technology Development (OTD) supports applied research and demonstration efforts to develop and transfer innovative, cost-effective technologies to its site clean-up and waste management programs within EM's Office of Environmental Restoration and Office of Waste Management. The purpose of the Technology Catalogue is to provide performance data on OTD-developed technologies to scientists and engineers assessing and recommending technical solutions within the Department's clean-up and waste management programs, as well as to industry, other federal and state agencies, and the academic community. OTD's applied research and demonstration activities are conducted in programs referred to as Integrated Demonstrations (IDs) and Integrated Programs (IPs). The IDs test and evaluate.systems, consisting of coupled technologies, at specific sites to address generic problems, such as the sensing, treatment, and disposal of buried waste containers. The IPs support applied research activities in specific applications areas, such as in situ remediation, efficient separations processes, and site characterization. The Technology Catalogue is a means for communicating the status. of the development of these innovative technologies. The FY93 Technology Catalogue features technologies successfully demonstrated in the field through IDs and sufficiently mature to be used in the near-term. Technologies from the following IDs are featured in the FY93 Technology Catalogue: Buried Waste ID (Idaho National Engineering Laboratory, Idaho); Mixed Waste Landfill ID (Sandia National Laboratories, New Mexico); Underground Storage Tank ID (Hanford, Washington); Volatile organic compound (VOC) Arid ID (Richland, Washington); and VOC Non-Arid ID (Savannah River Site, South Carolina)

  20. Viscous behavior of (Sn{sub 61.9}Pb{sub 38.1}){sub 100-x}RE{sub x} (x=0, 0.1, 0.3, 1 wt%) solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yuqin [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China); Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China)], E-mail: xfbian@sdu.edu.cn; Zhao Yan; Li Xuelian; Zhang Yanning; Tian Yongsheng; Lv Xiaoqian [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University (Southern Campus), 73 Jingshi Road, Jinan 250061 (China)

    2008-05-19

    The viscous behavior of (Sn{sub 61.9}Pb{sub 38.1}){sub 100-x}RE{sub x} (x=0, 0.1, 0.3, 1 wt%) solder alloys has been investigated by a torsional oscillation viscometer. The structural transition temperature T{sup '} increases with increasing addition of RE elements. Above T{sup '}, the viscosities of melts increase with increasing addition of RE, and are fitted well with the Arrhenius equation. The time dependence of viscosity at the measured temperature below T{sup '} follows the exponential relaxation function and reflects the process of the structural transition in the melt, which can be considered as the thermodynamic equilibrium process. The thermodynamic equilibrium relaxation time {tau}{sub eq} increases with both the equilibrium viscosity {eta}{sub eq} and the discrepancy in viscosity ({delta}{eta}), between the initial state and the equilibrium state. However, it decreases with the measured temperature T. The size of clusters in the melts increases with increasing of viscosity and is restricted by the thermodynamic equilibrium conditions.

  1. Thermally activated technologies: Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2003-05-01

    The purpose of this Technology Roadmap is to outline a set of actions for government and industry to develop thermally activated technologies for converting America’s wasted heat resources into a reservoir of pollution-free energy for electric power, heating, cooling, refrigeration, and humidity control. Fuel flexibility is important. The actions also cover thermally activated technologies that use fossil fuels, biomass, and ultimately hydrogen, along with waste heat.

  2. Technological Advancements

    Science.gov (United States)

    Kennedy, Mike

    2010-01-01

    The influx of technology has brought significant improvements to school facilities. Many of those advancements can be found in classrooms, but when students head down the hall to use the washrooms, they are likely to find a host of technological innovations that have improved conditions in that part of the building. This article describes modern…

  3. Maritime Technology

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1997-01-01

    Elementary introduction to the subject "Maritime Technology".The contents include drawings, sketches and references in English without any supplementary text.......Elementary introduction to the subject "Maritime Technology".The contents include drawings, sketches and references in English without any supplementary text....

  4. Technology collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Jacob [Halliburton (Brazil)

    2011-07-01

    The aim of this paper is to present Halliburton's Brazilian technology center. Halliburton has technology centers in the United States, Saudi Arabia, India, Singapore and Brazil, all of which aim at delivering accelerated innovation in the oil sector. The technology centers engage in research and development activities with the help of various universities and in collaboration with the customer or supplier. The Halliburton Brazil technology center provides its customers with timely research and development solutions for enhancing recovery and mitigating reservoir uncertainty; they are specialized in finding solutions for pre- and post-salt carbonate drilling and in the enhancement of production from mature fields. This presentation showcased the work carried out by the Halliburton Brazil technology center to help customers develop their deepwater field activities.

  5. Sensemaking technology

    DEFF Research Database (Denmark)

    Madsen, Charlotte Øland

    Research objective: The object of the LOK research project is to gain a better understanding of the technological strategic processes in organisations by using the concept/metaphor of sensemaking. The project will investigate the technological strategies in organisations in order to gain a deeper...... understanding of the cognitive competencies and barriers towards implementing new technology in organisations. The research will therefore concentrate on researching the development process in the organisation's perception of the external environmental elements of customers, suppliers, competitors, internal...... and external technology and legislation and the internal environmental elements of structure, power relations and political arenas. All of these variables have influence on which/how technologies are implemented thus creating different outcomes all depending on the social dynamics that are triggered by changes...

  6. Ergonomics technology

    Science.gov (United States)

    Jones, W. L.

    1977-01-01

    Major areas of research and development in ergonomics technology for space environments are discussed. Attention is given to possible applications of the technology developed by NASA in industrial settings. A group of mass spectrometers for gas analysis capable of fully automatic operation has been developed for atmosphere control on spacecraft; a version for industrial use has been constructed. Advances have been made in personal cooling technology, remote monitoring of medical information, and aerosol particle control. Experience gained by NASA during the design and development of portable life support units has recently been applied to improve breathing equipment used by fire fighters.

  7. Technology Innovation

    Science.gov (United States)

    EPA produces innovative technologies and facilitates their creation in line with the Agency mission to create products such as the stormwater calculator, remote sensing, innovation clusters, and low-cost air sensors.

  8. Videodisc technology

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, F.E. Jr.

    1981-03-01

    An overview of the technology of videodiscs is given. The emphasis is on systems that use reflection or transmission of laser light. Possible use of videodiscs for storage of bibliographic information is considered. 6 figures, 3 tables. (RWR)

  9. Technology | FNLCR

    Science.gov (United States)

    The Frederick National Laboratory develops and applies advanced, next-generation technologies to solve basic and applied problems in the biomedical sciences, and serves as a national resource of shared high-tech facilities.

  10. Globalization & technology

    DEFF Research Database (Denmark)

    Narula, Rajneesh

    of innovation" understanding of learning. Narula and Smith reconcile an important paradox. On the one hand, locations and firms are increasingly interdependent through supranational organisations, regional integration, strategic alliances, and the flow of investments, technologies, ideas and people......Technology and globalization are interdependent processes. Globalization has a fundamental influence on the creation and diffusion of technology, which, in turn, affects the interdependence of firms and locations. This volume examines the international aspect of this interdependence at two levels....... The boundaries of firms and countries are increasingly porous and imprecise, because firms use alliances and outsourcing, and countries are rarely technologically self-sufficient. On the other hand, locations remain distinct and idiosyncratic, with innovation systems remaining largely nationally bound. Knowledge...

  11. Plasma technology

    International Nuclear Information System (INIS)

    Drouet, M.G.

    1984-03-01

    IREQ was contracted by the Canadian Electrical Association to review plasma technology and assess the potential for application of this technology in Canada. A team of experts in the various aspects of this technology was assembled and each team member was asked to contribute to this report on the applications of plasma pertinent to his or her particular field of expertise. The following areas were examined in detail: iron, steel and strategic-metals production; surface treatment by spraying; welding and cutting; chemical processing; drying; and low-temperature treatment. A large market for the penetration of electricity has been identified. To build up confidence in the technology, support should be provided for selected R and D projects, plasma torch demonstrations at full power, and large-scale plasma process testing

  12. Exploration technology

    Energy Technology Data Exchange (ETDEWEB)

    Roennevik, H.C. [Saga Petroleum A/S, Forus (Norway)

    1996-12-31

    The paper evaluates exploration technology. Topics discussed are: Visions; the subsurface challenge; the creative tension; the exploration process; seismic; geology; organic geochemistry; seismic resolution; integration; drilling; value creation. 4 refs., 22 figs.

  13. Lasers technology

    International Nuclear Information System (INIS)

    2014-01-01

    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners

  14. Cognitive technologies

    CERN Document Server

    Mello, Alan; Figueiredo, Fabrício; Figueiredo, Rafael

    2017-01-01

    This book focuses on the next generation optical networks as well as mobile communication technologies. The reader will find chapters on Cognitive Optical Network, 5G Cognitive Wireless, LTE, Data Analysis and Natural Language Processing. It also presents a comprehensive view of the enhancements and requirements foreseen for Machine Type Communication. Moreover, some data analysis techniques and Brazilian Portuguese natural language processing technologies are also described here. .

  15. Technology cycles and technology revolutions

    Energy Technology Data Exchange (ETDEWEB)

    Paganetto, Luigi; Scandizzo, Pasquale Lucio

    2010-09-15

    Technological cycles have been characterized as the basis of long and continuous periods economic growth through sustained changes in total factor productivity. While this hypothesis is in part consistent with several theories of growth, the sheer magnitude and length of the economic revolutions experienced by humankind seems to indicate surmise that more attention should be given to the origin of major technological and economic changes, with reference to one crucial question: role of production and use of energy in economic development.

  16. Persuasive Technology

    DEFF Research Database (Denmark)

    This book constitutes the proceedings of the 5th International Conference on Persuasive Technology, PERSUASIVE 2010, held in Copenhagen Denmark in June 2010. The 25 papers presented were carefully reviewed and selected from 80 submissions. In addition three keynote papers are included in this vol......This book constitutes the proceedings of the 5th International Conference on Persuasive Technology, PERSUASIVE 2010, held in Copenhagen Denmark in June 2010. The 25 papers presented were carefully reviewed and selected from 80 submissions. In addition three keynote papers are included...... in this volume. The topics covered are emotions and user experience, ambient persuasive systems, persuasive design, persuasion profiles, designing for health, psychology of persuasion, embodied and conversational agents, economic incentives, and future directions for persuasive technology....

  17. Seafood Technology

    DEFF Research Database (Denmark)

    Børresen, Torger

    This presentation will fill the total picture of this conference between fisheries and aquaculture, blue biotech and bioconservation, by considering the optimal processing technology of marine resources from the raw material until the seafood reaches the plate of the consumer. The situation today...... must be performed such that total traceability and authenticity of the final products can be presented on demand. The most important aspects to be considered within seafood technology today are safety, healthy products and high eating quality. Safety can be divided into microbiological safety...... and not presenting any safety risk per se. Seafood is healthy due to the omega-3 fatty acids and the nutritional value of vitamins, peptides and proteins. The processing technology must however be performed such that these valuable features are not lost during production. The same applies to the eating quality. Any...

  18. Smart technology

    International Nuclear Information System (INIS)

    Bruckner, D.G.

    1991-01-01

    The success of smart technology in the pursuit of the Gulf War has accentuated the awareness of how the Safeguards and Security disciplines are changing in response to new weaponry. Throughout the Department of Energy Integrated Complex (IC) Safeguards and Security efforts such as: Protection Programs Operations; Materials, Controls and Accountability; Information Security; Computer Security; Operational Security; Personnel Security, Safeguards and/or Security (S and S) surveys, and Inspections and Evaluations are undergoing a reassessment and refocusing. Some of this is in response to such things as the DOE initiated Freeze Report and the Drell Report. An important aspect is also technological, adjusting the way business is done in light of the weapons, tools and processes/procedures becoming available. This paper addresses the S and S issues with the promise of using smart technology to develop new approaches and equipment across the IC

  19. Technology Transfer

    Science.gov (United States)

    Smith, Nanette R.

    1995-01-01

    The objective of this summer's work was to attempt to enhance Technology Application Group (TAG) ability to measure the outcomes of its efforts to transfer NASA technology. By reviewing existing literature, by explaining the economic principles involved in evaluating the economic impact of technology transfer, and by investigating the LaRC processes our William & Mary team has been able to lead this important discussion. In reviewing the existing literature, we identified many of the metrics that are currently being used in the area of technology transfer. Learning about the LaRC technology transfer processes and the metrics currently used to track the transfer process enabled us to compare other R&D facilities to LaRC. We discuss and diagram impacts of technology transfer in the short run and the long run. Significantly, it serves as the basis for analysis and provides guidance in thinking about what the measurement objectives ought to be. By focusing on the SBIR Program, valuable information regarding the strengths and weaknesses of this LaRC program are to be gained. A survey was developed to ask probing questions regarding SBIR contractors' experience with the program. Specifically we are interested in finding out whether the SBIR Program is accomplishing its mission, if the SBIR companies are providing the needed innovations specified by NASA and to what extent those innovations have led to commercial success. We also developed a survey to ask COTR's, who are NASA employees acting as technical advisors to the SBIR contractors, the same type of questions, evaluating the successes and problems with the SBIR Program as they see it. This survey was developed to be implemented interactively on computer. It is our hope that the statistical and econometric studies that can be done on the data collected from all of these sources will provide insight regarding the direction to take in developing systematic evaluations of programs like the SBIR Program so that they can

  20. Technology applications

    Science.gov (United States)

    Anuskiewicz, T.; Johnston, J.; Leavitt, W.; Zimmerman, R. R.

    1972-01-01

    A summary of NASA Technology Utilization programs for the period of 1 December 1971 through 31 May 1972 is presented. An abbreviated description of the overall Technology Utilization Applications Program is provided as a background for the specific applications examples. Subjects discussed are in the broad headings of: (1) cancer, (2) cardiovascular disease, (2) medical instrumentation, (4) urinary system disorders, (5) rehabilitation medicine, (6) air and water pollution, (7) housing and urban construction, (8) fire safety, (9) law enforcement and criminalistics, (10) transportation, and (11) mine safety.

  1. Architectural technology

    DEFF Research Database (Denmark)

    2005-01-01

    The booklet offers an overall introduction to the Institute of Architectural Technology and its projects and activities, and an invitation to the reader to contact the institute or the individual researcher for further information. The research, which takes place at the Institute of Architectural...... Technology at the Roayl Danish Academy of Fine Arts, School of Architecture, reflects a spread between strategic, goal-oriented pilot projects, commissioned by a ministry, a fund or a private company, and on the other hand projects which originate from strong personal interests and enthusiasm of individual...

  2. Technology Transfer: Marketing Tomorrow's Technology

    Science.gov (United States)

    Tcheng, Erene

    1995-01-01

    The globalization of the economy and the end of the Cold War have triggered many changes in the traditional practices of U.S. industry. To effectively apply the resources available to the United States, the federal government has firmly advocated a policy of technology transfer between private industry and government labs, in this case the National Aeronautics and Space Administration (NASA). NASA Administrator Daniel Goldin is a strong proponent of this policy and has organized technology transfer or commercialization programs at each of the NASA field centers. Here at Langley Research Center, the Technology Applications Group (TAG) is responsible for facilitating the transfer of Langley developed research and technology to U.S. industry. Entering the program, I had many objectives for my summer research with TAG. Certainly, I wanted to gain a more thorough understanding of the concept of technology transfer and Langley's implementation of a system to promote it to both the Langley community and the community at large. Also, I hoped to become more familiar with Langley's research capabilities and technology inventory available to the public. More specifically, I wanted to learn about the technology transfer process at Langley. Because my mentor is a member of Materials and Manufacturing marketing sector of the Technology Transfer Team, another overriding objective for my research was to take advantage of his work and experience in materials research to learn about the Advanced Materials Research agency wide and help market these developments to private industry. Through the various projects I have been assigned to work on in TAG, I have successfully satisfied the majority of these objectives. Work on the Problem Statement Process for TAG as well as the development of the Advanced Materials Research Brochure have provided me with the opportunity to learn about the technology transfer process from the outside looking in and the inside looking out. Because TAG covers

  3. Blast Technologies

    Science.gov (United States)

    2011-06-27

    Team Leader Risa Scherer Blast Mitigation Interior and Laboratory Team Leader Blast Technologies POC’s Government Point Of Contacts (POCs): To...to yield injury assessments at higher fidelities and with higher confidence UNCLASSIFIED UNCLASSIFIED Risa Scherer Blast Mitigation Interior and

  4. Health technology

    International Nuclear Information System (INIS)

    Nicolas, Delphine; Dangleant, Caroline; Ganier, Aude; Kaczmarek, Delphine

    2008-01-01

    The CEA is an organization with a primarily technological focus, and one of the key areas in which it carries out research is Health Technology. This field of research was recognized and approved by the French Atomic Energy Committee on July 20, 2004. The expectations of both the public and health care professionals relate to demands for the highest standards of health care, at minimum risk. This implies a need to diagnose illness and disease as accurately and as at early a stage as possible, to target surgery precisely to deal only with damaged organs or tissues, to minimize the risk of side effects, allergies and hospital-acquired infections, to follow-up and, as far as possible, tailor the health delivery system to each individual's needs and his or her lifestyle. The health care sector is subject to rapid changes and embraces a vast range of scientific fields. It now requires technological developments that will serve to gather increasing quantities of useful information, analyze and integrate it to obtain a full understanding of highly complex processes and to be able to treat the human body as un-invasively as possible. All the technologies developed require assessment, especially in the hospital environment. (authors)

  5. Technology transfer

    International Nuclear Information System (INIS)

    Boury, C.

    1986-01-01

    This paper emphasizes in the specific areas of design, engineering and component production. This paper presents what Framatome has to offer in these areas and its export oriented philosophy. Then, a typical example of this technology transfer philosophy is the collaboration with the South Korean firm, Korea Heavy Industries Corporation (KHIC) for the supply of KNU 9 and KNU 10 power stations

  6. Technology Transfer

    Science.gov (United States)

    Bullock, Kimberly R.

    1995-01-01

    The development and application of new technologies in the United States has always been important to the economic well being of the country. The National Aeronautics and Space Administration (NASA) has been an important source of these new technologies for almost four decades. Recently, increasing global competition has emphasized the importance of fully utilizing federally funded technologies. Today NASA must meet its mission goals while at the same time, conduct research and development that contributes to securing US economic growth. NASA technologies must be quickly and effectively transferred into commercial products. In order to accomplish this task, NASA has formulated a new way of doing business with the private sector. Emphasis is placed on forming mutually beneficial partnerships between NASA and US industry. New standards have been set in response to the process that increase effectiveness, efficiency, and timely customer response. This summer I have identified potential markets for two NASA inventions: including the Radially Focused Eddy Current Sensor for Characterization of Flaws in Metallic Tubing and the Radiographic Moire. I have also worked to establish a cooperative program with TAG, private industry, and a university known as the TAG/Industry/Academia Program.

  7. Energy Technology.

    Science.gov (United States)

    Eaton, William W.

    Reviewed are technological problems faced in energy production including locating, recovering, developing, storing, and distributing energy in clean, convenient, economical, and environmentally satisfactory manners. The energy resources of coal, oil, natural gas, hydroelectric power, nuclear energy, solar energy, geothermal energy, winds, tides,…

  8. (Environmental technology)

    Energy Technology Data Exchange (ETDEWEB)

    Boston, H.L.

    1990-10-12

    The traveler participated in a conference on environmental technology in Paris, sponsored by the US Embassy-Paris, US Environmental Protection Agency (EPA), the French Environmental Ministry, and others. The traveler sat on a panel for environmental aspects of energy technology and made a presentation on the potential contributions of Oak Ridge National Laboratory (ORNL) to a planned French-American Environmental Technologies Institute in Chattanooga, Tennessee, and Evry, France. This institute would provide opportunities for international cooperation on environmental issues and technology transfer related to environmental protection, monitoring, and restoration at US Department of Energy (DOE) facilities. The traveler also attended the Fourth International Conference on Environmental Contamination in Barcelona. Conference topics included environmental chemistry, land disposal of wastes, treatment of toxic wastes, micropollutants, trace organics, artificial radionuclides in the environment, and the use biomonitoring and biosystems for environmental assessment. The traveler presented a paper on The Fate of Radionuclides in Sewage Sludge Applied to Land.'' Those findings corresponded well with results from studies addressing the fate of fallout radionuclides from the Chernobyl nuclear accident. There was an exchange of new information on a number of topics of interest to DOE waste management and environmental restoration needs.

  9. Geospatial Technology

    Science.gov (United States)

    Reed, Philip A.; Ritz, John

    2004-01-01

    Geospatial technology refers to a system that is used to acquire, store, analyze, and output data in two or three dimensions. This data is referenced to the earth by some type of coordinate system, such as a map projection. Geospatial systems include thematic mapping, the Global Positioning System (GPS), remote sensing (RS), telemetry, and…

  10. Photovoltaic technologies

    International Nuclear Information System (INIS)

    Bagnall, Darren M.; Boreland, Matt

    2008-01-01

    Photovoltaics is already a billion dollar industry. It is experiencing rapid growth as concerns over fuel supplies and carbon emissions mean that governments and individuals are increasingly prepared to ignore its current high costs. It will become truly mainstream when its costs are comparable to other energy sources. At the moment, it is around four times too expensive for competitive commercial production. Three generations of photovoltaics have been envisaged that will take solar power into the mainstream. Currently, photovoltaic production is 90% first-generation and is based on silicon wafers. These devices are reliable and durable, but half of the cost is the silicon wafer and efficiencies are limited to around 20%. A second generation of solar cells would use cheap semiconductor thin films deposited on low-cost substrates to produce devices of slightly lower efficiency. A number of thin-film device technologies account for around 5-6% of the current market. As second-generation technology reduces the cost of active material, the substrate will eventually be the cost limit and higher efficiency will be needed to maintain the cost-reduction trend. Third-generation devices will use new technologies to produce high-efficiency devices. Advances in nanotechnology, photonics, optical metamaterials, plasmonics and semiconducting polymer sciences offer the prospect of cost-competitive photovoltaics. It is reasonable to expect that cost reductions, a move to second-generation technologies and the implementation of new technologies and third-generation concepts can lead to fully cost-competitive solar energy in 10-15 years. (author)

  11. Technology Programme

    International Nuclear Information System (INIS)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo

    2005-01-01

    The technology activities carried out by the Euratom-ENEA Association in the framework of the European Fusion Development Agreement concern the Next Step (International Thermonuclear Experimental Reactor - ITER), the Long-Term Programme (breeder blanket, materials, International Fusion Materials Irradiation Facility - IFMIF), Power Plant Conceptual Studies and Socio-Economic Studies. The Underlying Technology Programme was set up to complement the fusion activities as well to develop technologies with a wider range of interest. The Technology Programme mainly involves staff from the Frascati laboratories of the Fusion Technical and Scientific Unit and from the Brasimone laboratories of the Advanced Physics Technologies Unit. Other ENEA units also provide valuable contributions to the programme. ENEA is heavily engaged in component development/testing and in design and safety activities for the European Fusion Technology Programme. Although the work documented in the following covers a large range of topics that differ considerably because they concern the development of extremely complex systems, the high level of integration and coordination ensures the capability to cover the fusion system as a whole. In 2004 the most significant testing activities concerned the ITER primary beryllium-coated first wall. In the field of high-heat-flux components, an important achievement was the qualification of the process for depositing a copper liner on carbon fibre composite (CFC) hollow tiles. This new process, pre-brazed casting (PBC), allows the hot radial pressing (HRP) joining procedure to be used also for CFC-based armour monoblock divertor components. The PBC and HRP processes are candidates for the construction of the ITER divertor. In the materials field an important milestone was the commissioning of a new facility for chemical vapour infiltration/deposition, used for optimising silicon carbide composite (SiCf/SiC) components. Eight patents were deposited during 2004

  12. Technology Programme

    Energy Technology Data Exchange (ETDEWEB)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo (ed.)

    2005-07-01

    The technology activities carried out by the Euratom-ENEA Association in the framework of the European Fusion Development Agreement concern the Next Step (International Thermonuclear Experimental Reactor - ITER), the Long-Term Programme (breeder blanket, materials, International Fusion Materials Irradiation Facility - IFMIF), Power Plant Conceptual Studies and Socio-Economic Studies. The Underlying Technology Programme was set up to complement the fusion activities as well to develop technologies with a wider range of interest. The Technology Programme mainly involves staff from the Frascati laboratories of the Fusion Technical and Scientific Unit and from the Brasimone laboratories of the Advanced Physics Technologies Unit. Other ENEA units also provide valuable contributions to the programme. ENEA is heavily engaged in component development/testing and in design and safety activities for the European Fusion Technology Programme. Although the work documented in the following covers a large range of topics that differ considerably because they concern the development of extremely complex systems, the high level of integration and coordination ensures the capability to cover the fusion system as a whole. In 2004 the most significant testing activities concerned the ITER primary beryllium-coated first wall. In the field of high-heat-flux components, an important achievement was the qualification of the process for depositing a copper liner on carbon fibre composite (CFC) hollow tiles. This new process, pre-brazed casting (PBC), allows the hot radial pressing (HRP) joining procedure to be used also for CFC-based armour monoblock divertor components. The PBC and HRP processes are candidates for the construction of the ITER divertor. In the materials field an important milestone was the commissioning of a new facility for chemical vapour infiltration/deposition, used for optimising silicon carbide composite (SiCf/SiC) components. Eight patents were deposited during 2004

  13. Technological Networks

    Science.gov (United States)

    Mitra, Bivas

    The study of networks in the form of mathematical graph theory is one of the fundamental pillars of discrete mathematics. However, recent years have witnessed a substantial new movement in network research. The focus of the research is shifting away from the analysis of small graphs and the properties of individual vertices or edges to consideration of statistical properties of large scale networks. This new approach has been driven largely by the availability of technological networks like the Internet [12], World Wide Web network [2], etc. that allow us to gather and analyze data on a scale far larger than previously possible. At the same time, technological networks have evolved as a socio-technological system, as the concepts of social systems that are based on self-organization theory have become unified in technological networks [13]. In today’s society, we have a simple and universal access to great amounts of information and services. These information services are based upon the infrastructure of the Internet and the World Wide Web. The Internet is the system composed of ‘computers’ connected by cables or some other form of physical connections. Over this physical network, it is possible to exchange e-mails, transfer files, etc. On the other hand, the World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet where nodes represent web pages and links represent hyperlinks between the pages. Peer-to-peer (P2P) networks [26] also have recently become a popular medium through which huge amounts of data can be shared. P2P file sharing systems, where files are searched and downloaded among peers without the help of central servers, have emerged as a major component of Internet traffic. An important advantage in P2P networks is that all clients provide resources, including bandwidth, storage space, and computing power. In this chapter, we discuss these technological networks in detail. The review

  14. Innovative Technology in Automotive Technology

    Science.gov (United States)

    Gardner, John

    2007-01-01

    Automotive Technology combines hands-on training along with a fully integrated, interactive, computerized multistationed facility. Our program is a competency based, true open-entry/open-exit program that utilizes flexible self-paced course outlines. It is designed around an industry partnership that promotes community and economic development,…

  15. Playful Technology

    DEFF Research Database (Denmark)

    Johansen, Stine Liv; Eriksson, Eva

    2013-01-01

    In this paper, the design of future services for children in Danish public libraries is discussed, in the light of new challenges and opportunities in relation to new media and technologies. The Danish government has over the last few years initiated and described a range of initiatives regarding...... the future of public libraries, especially in relation to children as a particular user group. This paper explores play culture, and takes a stance especially in the project ‘Families at play in the library’, but also in experiences from related projects. The focus is on families playing together...... in the library, the changing role of the librarians and the library space. We argue that intertwining traditional library services with new media forms and engaging play is the core challenge for future design in physical public libraries, but also that it is through new media and technology that new...

  16. Technology transfer

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Illustrated by the example of the FRG's nuclear energy exports, it is shown that the nuclear technology transfer leads to new dimensions of intergovernmental relations, which hold within themselves on account of multiple state-to-state, scientific, industrial and - last but not least - personal contacts the chance of far-reaching friendships between countries and people. If the chance is taken, this can also be seen as an important contribution towards maintaining the peace. (orig.) [de

  17. Group technology

    International Nuclear Information System (INIS)

    Rome, C.P.

    1976-01-01

    Group Technology has been conceptually applied to the manufacture of batch-lots of 554 machined electromechanical parts which now require 79 different types of metal-removal tools. The products have been grouped into 7 distinct families which require from 8 to 22 machines in each machine-cell. Throughput time can be significantly reduced and savings can be realized from tooling, direct-labor, and indirect-labor costs

  18. Army Technology

    Science.gov (United States)

    2015-02-01

    MUTT ) is a semi-autonomous robotic follower that lightens the load for Soldiers by decreasing the amount of equipment they need to carry when...dismounted in the toughest of terrains. The MUTT uses advanced, proven commercial technology that has been adapted for the rigors of the battlefield...With ultra-quiet electric motors, the MUTT gives Soldiers unmatched internal transportability options and expeditionary power that includes hands- free

  19. ADSL Technology

    Directory of Open Access Journals (Sweden)

    Slavko Šarić

    2002-11-01

    Full Text Available The paper deals with the ADSL (Asymmetric Digital SubscriberLine technology- the asymmetric digital telecommunicationtechnology. It is characterised by high-speed transmissionof data and simultaneous transmission of information regardingthe throughput capacity of the telephone network. Thisresults in better efficiency of transmission, and higher utilisationof the bandwidth. Due to its advantages, the use of ADSLtechnology is increasing daily, especially by ente1prises in Europeand worldwide.

  20. Nuclear technology

    International Nuclear Information System (INIS)

    1983-03-01

    This report examines nuclear technology in Canada, with emphasis on Quebec, as a means of revitilizing industry. The historical, present day, and future states of Atomic Energy of Canada Limited are examined. Future research programs are discussed in greatest detail. These range from disposal of porcine wastes to new applications for electricity to nuclear medical techniques (to cite only a few examples). The executive summary is written in English. (23 fig., 16 tab.)

  1. Emerging technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee

    1993-03-01

    The mission of the Emerging Technologies thrust area at Lawrence Livermore National Laboratory is to help individuals establish technology areas that have national and commercial impact, and are outside the scope of the existing thrust areas. We continue to encourage innovative ideas that bring quality results to existing programs. We also take as our mission the encouragement of investment in new technology areas that are important to the economic competitiveness of this nation. In fiscal year 1992, we have focused on nine projects, summarized in this report: (1) Tire, Accident, Handling, and Roadway Safety; (2) EXTRANSYT: An Expert System for Advanced Traffic Management; (3) Odin: A High-Power, Underwater, Acoustic Transmitter for Surveillance Applications; (4) Passive Seismic Reservoir Monitoring: Signal Processing Innovations; (5) Paste Extrudable Explosive Aft Charge for Multi-Stage Munitions; (6) A Continuum Model for Reinforced Concrete at High Pressures and Strain Rates: Interim Report; (7) Benchmarking of the Criticality Evaluation Code COG; (8) Fast Algorithm for Large-Scale Consensus DNA Sequence Assembly; and (9) Using Electrical Heating to Enhance the Extraction of Volatile Organic Compounds from Soil.

  2. Technology Management

    DEFF Research Database (Denmark)

    Pilkington, Alan

    2014-01-01

    This paper reports a bibliometric analysis (co-citation network analysis) of 10 journals in the management of technology (MOT) field. As well as introducing various bibliometric ideas, network analysis tools identify and explore the concepts covered by the field and their inter-relationships. Spe......This paper reports a bibliometric analysis (co-citation network analysis) of 10 journals in the management of technology (MOT) field. As well as introducing various bibliometric ideas, network analysis tools identify and explore the concepts covered by the field and their inter......-relationships. Specific results from different levels of analysis show the different dimensions of technology management: • Co-word terms identify themes • Journal co-citation network: linking to other disciplines • Co-citation network show concentrations of themes The analysis shows that MOT has a bridging role...... in integrating ideas from several distinct disciplines. This suggests that management and strategy are central to MOT which essentially relates to the firm rather than policy. Similarly we have a dual focus on capabilities, but can see subtle differences in how we view these ideas, either through an inwards...

  3. Wearable Technology

    Science.gov (United States)

    Watson, Amanda

    2013-01-01

    Wearable technology projects, to be useful, in the future, must be seamlessly integrated with the Flight Deck of the Future (F.F). The lab contains mockups of space vehicle cockpits, habitat living quarters, and workstations equipped with novel user interfaces. The Flight Deck of the Future is one element of the Integrated Power, Avionics, and Software (IPAS) facility, which, to a large extent, manages the F.F network and data systems. To date, integration with the Flight Deck of the Future has been limited by a lack of tools and understanding of the Flight Deck of the Future data handling systems. To remedy this problem it will be necessary to learn how data is managed in the Flight Deck of the Future and to develop tools or interfaces that enable easy integration of WEAR Lab and EV3 products into the Flight Deck of the Future mockups. This capability is critical to future prototype integration, evaluation, and demonstration. This will provide the ability for WEAR Lab products, EV3 human interface prototypes, and technologies from other JSC organizations to be evaluated and tested while in the Flight Deck of the Future. All WEAR Lab products must be integrated with the interface that will connect them to the Flight Deck of the Future. The WEAR Lab products will primarily be programmed in Arduino. Arduino will be used for the development of wearable controls and a tactile communication garment. Arduino will also be used in creating wearable methane detection and warning system.

  4. Understanding Technology?

    Directory of Open Access Journals (Sweden)

    Erik Bendtsen

    2016-11-01

    Full Text Available We are facing radical changes in our ways of living in the nearest future. Not necessarily of our own choice, but because tchnological development is moving so fast, that it will have still greater impact on many aspects of our lives. We have seen the beginnings of that change within the latest 35 years or so, but according to newest research that change will speed up immensely in the nearest years to come. The impact of that change or these changes will affect our working life immensely as a consequence of automation. How these changes are brought about and which are their consequences in a broad sense is being attempted to be understood and guessed by researchers. No one knows for sure, but specific patterns are visible. This paper will not try to guess, what will come, but will rather try to understand the deepest ”nature” of technology in order to understand the driving factors in this development: the genesis of technology in a broad sense in order to contibute to the understanding of the basis for the expected development.

  5. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  6. Architectural Technology and Technological Planning

    Directory of Open Access Journals (Sweden)

    Giorgio Giallocosta

    2011-11-01

    Full Text Available At least three fundamental aspects of the many singular technological approaches to architectural planning are currently evolving significantly and are ripe for potential development. The first relates to enhanced opportunities for defining the ex-ante characteristics and performance of building products and components, but particularly concerns potential leadership assumptions in planning and the ‘reification’ of architecture through ‘collective’ behaviours. The second relates to the tendency to try and overcome the connotation of architectural projects, inclusive of their entire life cycle. The third relates to current evolutionary developments (either potential or simply implicit in performance approach.

  7. Technology round and management of technology

    International Nuclear Information System (INIS)

    Park, Yong Tae

    1994-04-01

    This book deals with beginning of technology round with background of it, change of scientific technique paradigm with economy, management and policy, change of international political environment globalization of technical and economic environment, formation of strategic alliance, intensifying regionalism, new GATT system, UR and technology round, new international technique regulation and technology round of OECD, feature and meaning of technology round, assignment and scientific technique of Korea, past and present of scientific technology in Korea, correspondence for technology round.

  8. Incineration technologies

    CERN Document Server

    Buekens, Alfons

    2013-01-01

    Waste incineration is the art of completely combusting waste, while maintaining or reducing emission levels below current emission standards. Where possible, objectives include the recovering of energy as well as the  combustion residues.  Successful waste incineration makes it possible to achieve a deep reduction in waste volume, obtain a compact and sterile residue, and eliminate a wide array of pollutants. This book places waste incineration within the wider context of waste management, and demonstrates that, in contrast to landfills and composting, waste incineration can eliminate objectionable and hazardous properties such as flammability and toxicity, result in a significant reduction in volume, and destroy gaseous and liquid waste streams leaving little or no residues beyond those linked to flue gas neutralization and treatment. Moreover, waste incineration sterilizes and destroys putrescible matter, and produces usable heat.  Incineration Technologies first appeared as a peer-reviewed contribution ...

  9. Robot technology

    International Nuclear Information System (INIS)

    Vertut, Jean; Coiffet, Philippe.

    1985-01-01

    Teleoperation is concerned with the exploration and exploitation of of spaces which do not allow, because of their inaccessibility or hostility, direct access to man. This volume (Parts 2, 3 and 4) covers the contribution of computer science and automatic control to this technology. Part 2 includes a description of teleoperation systems followed by chapters on the operator substitution function by computer feedback to the operator. Part 3 has chapters on performance evaluation of teleoperation systems and the human operator in the teleoperation system. Part 4 is about applications of teleoperation in the nuclear industry, underwater, in space, in medicine, in industry and in security and civil protection. The nuclear applications include research and pilot facilities, reactor operation and maintenance, reactor decommissioning and dismantling and in emergencies, for example following a reactor accident. (U.K.)

  10. Lander Technologies

    Science.gov (United States)

    Chavers, Greg

    2015-01-01

    Since 2006 NASA has been formulating robotic missions to the lunar surface through programs and projects like the Robotic Lunar Exploration Program, Lunar Precursor Robotic Program, and International Lunar Network. All of these were led by NASA Marshall Space Flight Center (MSFC). Due to funding shortfalls, the lunar missions associated with these efforts, the designs, were not completed. From 2010 to 2013, the Robotic Lunar Lander Development Activity was funded by the Science Mission Directorate (SMD) to develop technologies that would enable and enhance robotic lunar surface missions at lower costs. In 2013, a requirements-driven, low-cost robotic lunar lander concept was developed for the Resource Prospector Mission. Beginning in 2014, The Advanced Exploration Systems funded the lander team and established the MSFC, Johnson Space Center, Applied Physics Laboratory, and the Jet Propulsion Laboratory team with MSFC leading the project. The lander concept to place a 300-kg rover on the lunar surface has been described in the New Technology Report Case Number MFS-33238-1. A low-cost lander concept for placing a robotic payload on the lunar surface is shown in figures 1 and 2. The NASA lander team has developed several lander concepts using common hardware and software to allow the lander to be configured for a specific mission need. In addition, the team began to transition lander expertise to United States (U.S.) industry to encourage the commercialization of space, specifically the lunar surface. The Lunar Cargo Transportation and Landing by Soft Touchdown (CATALYST) initiative was started and the NASA lander team listed above is partnering with three competitively selected U.S. companies (Astrobotic, Masten Space Systems, and Moon Express) to develop, test, and operate their lunar landers.

  11. Powder technology

    International Nuclear Information System (INIS)

    Agueda, Horacio

    1989-01-01

    Powder technology is experiencing nowadays a great development and has broad application in different fields: nuclear energy, medicine, new energy sources, industrial and home artifacts, etc. Ceramic materials are of daily use as tableware and also in the building industry (bricks, tiles, etc.). However, in machine construction its utilization is not so common. The same happens with metals: powder metallurgy is employed less than traditional metal forming techniques. Both cases deal with powder technology and the forming techniques as far as the final consolidation through sintering processes are very similar. There are many different methods and techniques in the forming stage: cold-pressing, slip casting, injection molding, extrusion molding, isostatic pressing, hot-pressing (which involves also the final consolidation step), etc. This variety allows to obtain almost any desired form no matter how complex it could be. Some applications are very specific as in the case of UO 2 pellets (used as nuclear fuels) but with the same technique and other materials, it is possible to manufacture a great number of different products. This work shows the characteristics and behaviour of two magnetic ceramic materials (ferrites) fabricated in the laboratory of the Applied Research Division of the Bariloche Atomic Center for different purposes. Other materials and products made with the same method are also mentioned. Likewise, densities and shrinkage obtained by different methods of forming (cold-pressing, injection molding, slip casting and extrusion molding) using high-purity alumina (99.5% Al 2 O 3 ). Finally, different applications of such methods are given. (Author) [es

  12. vZ - Maximal Satisfaction with Z3

    DEFF Research Database (Denmark)

    Bjørner, Nikolaj; Dung, Phan Anh

    2015-01-01

    Satisfiability Modulo Theories, SMT, solvers are used in many applications. These applications benefit from the power of tuned and scalable theorem proving technologies for supported logics and specialized theory solvers. SMT solvers are primarily used to determine whether formulas are satisfiabl...

  13. Technology programme

    International Nuclear Information System (INIS)

    2007-01-01

    The technology activities carried out by the EURATOM-ENEA Association concern the continuation of the European Fusion Development Agreement (EFDA) as well as the ITER activities coordinated by the ITER International Office and Fusion for Energy. Also included in the activities are design and RD under the Broader Approach Agreement between the EU and Japan. In order to better contribute to the programme a number of consortium agreements among the Associations are being signed. Collaboration with industries in view of their participation in the construction of ITER was further strengthened, mainly in the field of magnet and divertor components. The new European Test Blanket Facility at ENEA Brasimone was completed; the design of the ITER radial neutron camera was optimised and the performance achievable with the in-vessel viewing system was further assessed by experimental trials. Design activities for the JT-60SA magnet and power supply system as well as the design and experimental activities related to the target of the International Fusion Materials Irradiation Facility were continued. Significant work was done to define quality assurance for neutronics analyses. Mockups of the ITER pre-compression ring made in glass fibre epoxy were tested. The activities and results documented in the following illustrate ENEA's efforts to support fusion development

  14. How Technology Teachers Understand Technological Knowledge

    Science.gov (United States)

    Norström, Per

    2014-01-01

    Swedish technology teachers' views of technological knowledge are examined through a written survey and a series of interviews. The study indicates that technology teachers' understandings of what constitutes technological knowledge and how it is justified vary considerably. The philosophical discussions on the topic are unknown to them. This lack…

  15. International technology transfer

    International Nuclear Information System (INIS)

    Kwon, Won Gi

    1991-11-01

    This book introduces technology progress and economic growth, theoretical consideration of technology transfer, policy and mechanism on technology transfer of a developed country and a developing country, reality of international technology transfer technology transfer and industrial structure in Asia and the pacific region, technology transfer in Russia, China and Eastern Europe, cooperation of science and technology for development of Northeast Asia and strategy of technology transfer of Korea.

  16. A module concept for the upgrades of the ATLAS pixel system using the novel SLID-ICV vertical integration technology

    CERN Document Server

    Beimforde, M; Macchiolo, A; Moser, H G; Nisius, R; Richter, R H; Weigell, P; 10.1088/1748-0221/5/12/C12025

    2010-01-01

    The presented R&D activity is focused on the development of a new pixel module concept for the foreseen upgrades of the ATLAS detector towards the Super LHC employing thin n-in-p silicon sensors together with a novel vertical integration technology. A first set of pixel sensors with active thicknesses of 75 μm and 150 μm has been produced using a thinning technique developed at the Max-Planck-Institut für Physik (MPP) and the MPI Semiconductor Laboratory (HLL). Charge Collection Efficiency (CCE) measurements of these sensors irradiated with 26 MeV protons up to a particle fluence of 1016neqcm−2 have been performed, yielding higher values than expected from the present radiation damage models. The novel integration technology, developed by the Fraunhofer Institut EMFT, consists of the Solid-Liquid InterDiffusion (SLID) interconnection, being an alternative to the standard solder bump-bonding, and Inter-Chip Vias (ICVs) for routing signals vertically through electronics. This allows for extracting the ...

  17. Laser tabbed die: A repairable, high-speed die-interconnection technology. 1994 LDRD final report 93-SR-089

    Energy Technology Data Exchange (ETDEWEB)

    Malba, V.; Bernhardt, A.F.

    1995-09-01

    A unique technology for multichip module production is presented. The technology, called Laser Tabbed Die (L-TAB), consists of a method for forming surface-mount-type {open_quotes}gull wing{close_quotes} interconnects on bare dice. The dice are temporarily bonded to a sacrificial substrate which has a polymer thin film coated onto it. The gull wings are formed on the side of the die with a direct-write laser patterning process which allows vertical as well as horizontal image formation. Using the laser patterning system, trenches are formed in a positive electrodeposited photoresist (EDPR) which is plated onto a metal seed layer, allowing copper to be electroplated through the resultant mask. After stripping the resist and the metal seed layer, the polymer film on the substrate is dissolved, releasing the chip with the {open_quotes}gull wings{close_quotes} intact. The chips are then bonded onto a circuit board or permanent substrate with solder or conductive adhesive.

  18. Technological capabilities, technological dynamism and innovation offshoring

    OpenAIRE

    Schubert, Torben; Baier, Elisabeth; Rammer, Christian

    2016-01-01

    In this paper we analyze the conditions under which firms decide to offshore innovation. We consider the role of internal technological capabilities and technological dynamism in the firm environment, distinguishing speed and uncertainty of technological change. Using unique data from the German Innovation Survey we find that while high speed of technological change tends to drive innovation offshoring, high uncertainty about future technology developments results in more innovation offsho...

  19. Flywheel Technology

    Science.gov (United States)

    Ritchie, Lisa M.

    2004-01-01

    Throughout the summer of 2004, I am working on a number of different projects. While located in the Space Power and Propulsion Test Engineering branch, my main area of study is flywheel technology. I have been exposed to flywheels, their components, and their uses in today's society. I have been able to experience numerous flywheels here in the flywheel lab at NASA Glenn. My first main project was to explore the attributes and physical characteristics of a flywheel. Our branch was constructing a flywheel demonstration to be presented at the public open house taking place in June. Our Flywheel Interactive Demo, or FIDO, represents a real life multi-flywheel system here at NASA. I was given the opportunity to learn about how these flywheels store energy and are able to position a satellite. With all of this new knowledge, I was able to create the posters that explained how our demonstration worked. I also composed a step-by-step process made up of four experiments that any visitor could follow and perform on FIDO. By stepping through these experiments, the individual learns how a flywheel works. They not only read the explanation of what is happening, but they are also able to see it happen. Creating these two posters not only taught me, but also helped teach the general public during the open house, how flywheel technology is a very important part of our future. Through my research, I have learned that flywheels are able to store massive amounts of energy. They can be described as an electro-mechanical battery that stores kinetic energy while rotating. The faster it rotates, the more energy it stores. Their lifetime is about triple that of an ordinary battery. Flywheels also have the ability to combine energy storage with attitude control all in a single system. Attitude control is the ability to position a satellite as required. FIDO helps us to understand the rotational force (torque) that is applied upon a turn-table or satellite during wheel acceleration

  20. [Soldering for fixed prostheses. A critical analysis].

    Science.gov (United States)

    Cubero Postigo, G

    1989-04-01

    In this study about in fixed prosthodontics, it's observed that casts must be built in one piece in bridges with rigid frame. Thus, occlusal contacts must fall upon closeness the abutments of bridges.