A novel lead-free solder replacement (original) (raw)
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Lead-free solder materials-state of art and perspectives for the future
Lead was until recently a widely used element in many components of the electronics industry. It appears in the solder material, coatings soldered on printed circuit boards, pins and ends of boards. On one hand, the commonness of the electronic equipment which accompanies almost every aspect of our lives (~ 8 million tones of waste per year in EU countries) and on the other hand, great dispersion of lead within it, made Pb recovery and recycling impossible. As a result of wastes, corrosion toxic lead compounds were passing into groundwater and contributing to environmental pollution. Harmful effect of lead on human health is well known -its accumulation in the body causes disorders in the nervous and reproductive systems, the delays in neurological and physical development, anemia and hypertension. In the 90's of the last century Japan and the U.S. began research on the replacements of typical PbSn solders. Among the countries of the European Union breakthrough came about 10 yea...
Springer eBooks, 2016
Driven by RoHS regulation, the world has been migrating toward leadfree soldering since late 1990s. In this chapter, the main stream lead-free soldering practice was presented, and the properties of lead-free solder materials and soldering joints, including intermetallic compounds and microstructure evolution, were exemplified and discussed. Furthermore, the major categories of reliability of solder joints, including temperature cycling, fragility, electromigration, and tin whisker, were described and the mechanism was elucidated. Lastly, the trends and status of novel lead-free solder alloys, including low temperature, low cost and high reliability, and high temperature alloys were briefly introduced and reviewed.
IAEME, 2019
Overview of the current advances in lead-free solder, with highlighting the effects of various alloying elements is discussed in this paper. Also discussed is nanoparticle additions in solder alloy, as new prospects for innovative ways to enhance solder strength and reliability. Developing a high strength solder not containing lead is a challenging task, and we still needs to advance our knowledge of ternary and quaternary lead-free solder systems, from physical metallurgy. This paper discusses various alternative lead-free solders.
Lead (Pb)-Free Solder Applications
2000
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 userange of present-day, electrical components.
1996 Proceedings 46th Electronic Components and Technology Conference
Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of SnAg -Bi and SnAg -Cu-Sb lead-free solders by the controlled addition of 63Sn-37Pb solder at levels of 0.5-8.0 wL%. Thermal analysis and ring-in-plug shear strength studies were conducted on bulk solder properties. Circuit board prototype studies centered on the performance of 20VO SOIC gull wing joints. Both alloys exhibited declines in their melting temperatures with greater Sn-Pb additions. The ringin-plug shear strength of the SnAg -Cu-Sb solder increased slightly with Sn-Pb levels while the SnAg -Bi alloy experienced a strength loss. The mechanical behavior of the SOIC SnAg -Bi solder joints reproduced the strength drop to Sn-Pb contamination; however, the strength levels were insensitive to 10,106 thermal cycles. The SnAg -Cu-Sb solder showed a slight decrease in the gull wing joint strengths that was sensitive to the Pb content of the surface finish.
Reliability of solder joints assembled with lead-free solder
2002
To protect the natural environment, we will introduce the use of lead-free solder instead of the current tin-lead solder in the assembly of printed circuit boards in electronics equipment. During the transition to lead-free soldering, these two types of solders will be used in combination in joints. After the transition, a new element, bismuth, from components will contaminate the lead-free solder joints. We investigated the two types of solder through dynamic mechanical examination and concluded that lead-free solder can be used in combination with the current tin-lead solder and on its own to form sufficiently reliable joints.
2009
After the RoHS and WEEE directives came into force on 1 July 2006, producers of certain categories of electrical and electronic equipment are not able to place on the market products that contain lead, mercury, hexavalent chromium, cadmium, polybrominated biphenyl flame retardants and polybrominated diphenyl ether flame retardants. Therefore, solders, as commonly used electronic materials, had to be redesigned into lead-free solder materials, which were widely investigated in the last decade. The quality requirements for lead-free solders implementation in electronics, according to ISO 14040, are presented in this paper through the life cycle assessment analysis of these advanced ecological materials.