Journal ArticleDOI
Investigation of multi-component lead-free solders
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TLDR
In this paper, the contact angles of a number of solder-flux combinations on copper were directly measured in spreading tests and the most likely successful approach to obtain satisfactory wetting with lead-free solders appears to be development of a satisfactory flux.Abstract:
Binary phase diagrams of interest for lead-free solder development have been entered into the THERMO-CALC data base. These may be used directly to calculate multi-component phase relations vs temperature provided there are no ternary or higher order interactions. Such occur in the Sn-Ag-Zn system and are being evaluated. Contact angles of a number of solder-flux combinations on copper were directly measured in spreading tests. With a rosin-isopropyl alcohol flux, the contact angles of binary eutectic solders were in degrees: Sn-Bi at 166°C, 40; Sn-Zn at 225°C, 60; Sn-Ag at 250°C, 45. These angles were little affected by a number of 1% ternary additions to the solder. The contact angles were 20 degrees or less when SnCl2 was used as a flux. The SnCl2 reacts with Cu to form Cu3Sn. The most likely successful approach to obtain satisfactory wetting with lead-free solders appears to be development of a satisfactory flux.read more
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Journal ArticleDOI
Lead-free Solders in Microelectronics
Mulugeta Abtew,Guna S Selvaduray +1 more
TL;DR: The most widely used Pb-free solders have the eutectic composition as mentioned in this paper, which has been identified as a major factor affecting alloy selection, since this will have a major impact on the other polymeric materials used in microelectronic assembly and encapsulation.
Journal ArticleDOI
Advances in lead-free electronics soldering
TL;DR: In this paper, phase diagrams of lead-free alloy systems have been intensively examined by using careful thermal and microstructural analysis combined with the thermodynamic calculation such as the CLAPHAD method.
Journal ArticleDOI
A review : On the development of low melting temperature Pb-free solders
TL;DR: This review discusses fundamental research activity and its focus on the solidification and interfacial reactions of Sn-based solder systems, and first explains the reactions between common base materials, coatings, and metallisations, and then proceed to more complex systems with additional alloying elements.
Journal ArticleDOI
Mechanical fatigue characteristics of Sn-3.5Ag-x (X=Bi, Cu, Zn and In) solder alloys
Yoshiharu Kariya,Masahisa Otsuka +1 more
TL;DR: In this article, the effect of copper, zinc, and indium on the isothermal fatigue properties of Sn-3.5%Ag alloy has been investigated, and the relationship between fatigue life and crack propagation rate estimated from load drop curve during fatigue test is also discussed.
References
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Journal ArticleDOI
The Thermo-Calc databank system☆
TL;DR: Using the facilities of Thermo-Calc one can tabulate thermodynamic data, calculate the heat change of chemical reactions and their driving force, evaluate equilibria for chemical systems and phase transformations and calculate various types of multicomponent phase diagrams by an automatic mapping procedure.
Journal ArticleDOI
New Pb‐free solder alloy with superior mechanical properties
TL;DR: In this paper, a relatively small addition of Zn significantly improves the mechanical strength of Sn•3.5% Ag eutectic solders while maintaining the same level of ductility, which is attributed to a substantial refinement of the precipitates in the solidification microstructure.