1,061 research outputs found

    Technology of Welding and Joining

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    In this book, you will find information on new materials and new welding technologies. Problems related to the welding of difficult-to-weld materials are considered and solved. The latest welding technologies and processes are presented. This book provides an opportunity to learn about the latest trends and developments in the welding industry. Enjoy reading

    Corrosion Resistance

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    The book has covered the state-of-the-art technologies, development, and research progress of corrosion studies in a wide range of research and application fields. The authors have contributed their chapters on corrosion characterization and corrosion resistance. The applications of corrosion resistance materials will also bring great values to reader's work at different fields. In addition to traditional corrosion study, the book also contains chapters dealing with energy, fuel cell, daily life materials, corrosion study in green materials, and in semiconductor industry

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

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    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

    Bonding and adjoining technology: A compilation

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    This compilation covers NASA and AEC developed techniques covering bonding, brazing, and joining methods and technology

    Effect Of Pad Roughness On Shear Strength Of Thin Small Leadless Package

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    Thin Small Leadless Packages (TSLP) have been manufactured to cater the current industry demand for a smaller electronic apparatus with a higher electrical performance. Previous studies showed the solder joint strength of leadless package with the printed circuit board (PCB) using Ni-P/Sn-0.5 Ag solder were influenced by soldering and reflow parameters. Nevertheless, scattered studies have been reported on the effect of surface roughness (Ra) of leadless package on its solder joint strength. The current study investigated effect of Ra of TSLP on the solder joint strength between the TSLP and PCB. In the current study, Ra of package’s contact pad were varied using different Cu alloy leadframe materials (i.e. C194 and EFTECH-64) and etching process parameters (i.e. pH, specific Cu density and conveyor speed). This study also investigated the effect of Ni-P plating thickness and solder reflow conditions (i.e. temperature and duration) on the solder joint strength. Shear test was conducted on the soldered samples using Dage Series 4000 Bond Tester as per Infineon’s Control Plan Specifications, with the shear strength data represented the solder strength values. Subsequently, the discussion of solder strength results were supported by the failure mode results of the shear test samples, generated by scanning electron microscopy (SEM, JOEL JSM-6360A) images and energy dispersive Xray (EDX, JOEL JSM-6360A) analysis. An increase of Ni-P thickness on the etched samples reduced their Ra, thus resulted in a higher solder joint strength and smaller strength variation. Porous solder region in the soldered samples contributed to Mode 1 failure (i.e. fracture at solder region), which were exhibited by more than 80% of shear test samples. Only small percentages of shear samples showed Mode 2 (i.e. fracture at IMC and Ni-P layer interface) and Mode 3 (i.e. fracture at Ni-P and Ni bump interface). The percentage of Mode 2 and 3 failures were lower (i.e. composed of less than 5% of shear test samples) in low Ra samples. This could be explained by the improved solder wettability and strengthening of the IMC layer on the low Ra Ni-P plated samples

    Introductory Chapter: Overview of Recent Progress in Soldering Materials

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    Deposition and application of electroless Ni–W–P under bump metallisation for high temperature lead-free solder interconnects

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    A reliable and robust diffusion barrier, commonly known as under bump metallisation (UBM), is indispensable in solder interconnects in order to retard the interfacial reaction rate, hence the growth of intermetallic compounds (IMCs). However, electroless Ni-P coatings are not adequate to inhibit interfacial reactions effectively since the formation of columnar structure and voids in the crystalline Ni3P layer in hybrid automotive devices (operating temperature above 300ºC) can significantly deteriorate the mechanical integrity of solder joints. In this thesis, electroless Ni-W-P coatings, as an effective UBM capable to serving under high temperature (up to 450ºC), are developed, characterised and subsequently applied onto the high temperature lead-free solder interconnects. [Continues.
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