ADVANCES IN LEAD-FREE SOLDERS (original) (raw)
Related papers
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...
NEW TYPES OF LEAD-FREE SOLDERS AND THEIR PROPERTIES
The aim of this work is an experimental study of lead-free solders. Ternary and binary alloys with different ratios of individual elements Ag, Al, Bi, Cu, In, Mg, Sb, Sn and Zn were prepared experimentally. The study of low-fusing solder alloys was performed with the aspect of observing their selected physical, chemical, structural and technological properties. The following characteristics were studied: temperatures and enthalpies of phase transformations (DTA, TG, DSC) of individual solders at the rates of re-heating and cooling of specimens of about 4°C/min, macro-and micro-structural analysis (optical metallography), micro-hardness, chemical analysis: ICP-AES, optical emission spectrometry (OES), X-ray micro-analysis of individual phases in the structure of solders (WDX, EDX), measurement of density and electrical resistivity of selected solders in dependence on the temperature, test of wettability with or without use of fluxes, measurement of corrosion properties.
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.
A novel lead-free solder replacement
1994
Environmental and toxicity concerns related to the use of lead have initiated the search for acceptable, alternate joining materials for electronics assembly. This paper describes a novel lead-free solder designed as a ``drop in`` replacement for common tin/lead eutectic ...
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.
High Strength Lead-Free Composite Solder Materials using Nano Al2O3 as Reinforcement
Advanced Engineering Materials, 2005
Thermal shock tests: Thermal shock experiments were performed by quenching specimens from higher temperature in water for different cycles. The composite specimens were placed in an alumina (> 99.8 %) holder and heated in air atmosphere in a MoSi 2 furnace at 1200 C for 3 min to ensure uniformity of temperature. The specimens were then quenched into a water bath at 25 C for 2 min. The time elapsed between the opening of the furnace and the moment the specimens touching the water was approximately 5 s.
Development of nano-composite lead-free electronic solders
Journal of Electronic Materials, 2005
Inert, hybrid inorganic/organic, nano-structured chemicals can be incorporated into low melting metallic materials, such as lead-free electronic solders, to achieve desired levels of service performance. The nano-structured materials technology of polyhedral oligomeric silsesquioxanes (POSS), with appropriate organic groups, can produce suitable means to promote bonding between nano-reinforcements and the metallic matrix. The microstructures of lead-free solder reinforced with surface-active POSS tri-silanols were evaluated using scanning electron microscopy (SEM). Wettability of POSS-containing lead-free solders to copper substrate was also examined. Steady-state deformation of solder joints made of eutectic Sn-Ag solder containing varying weight fractions of POSS of different chemical moieties were evaluated at different temperatures (25°C, 100°C, and 150°C) using a rheometric solids analyzer (RSA-III). Mechanical properties such as shear stress versus simple shear-strain relationships, peak shear stress as a function of rate of simple shear strain, and testing temperature for such nano-composite solders are reported. The service reliability of joints made with these newly formulated nano-composite solders was evaluated using a realistic thermomechanical fatigue (TMF) test profile. Evolution of microstructures and residual mechanical property after different extents of TMF cycles were evaluated and compared with joints made of standard, unreinforced eutectic Sn-Ag solder.
Nanoparticles of the Lead-free Solder Alloy Sn-3.0Ag-0.5Cu with Large Melting Temperature Depression
Journal of Electronic Materials, 2009
Due to the toxicity of lead (Pb), Pb-containing solder alloys are being phased out from the electronics industry. This has lead to the development and implementation of lead-free solders. Being an environmentally compatible material, the lead-free Sn-3.0Ag-0.5Cu (wt.%) solder alloy is considered to be one of the most promising alternatives to replace the traditionally used Sn-Pb solders. This alloy composition possesses, however, some weaknesses, mainly as a result of its higher melting temperature compared with the Sn-Pb solders. A possible way to decrease the melting temperature of a solder alloy is to decrease the alloy particle size down to the nanometer range. The melting temperature of Sn-3.0Ag-0.5Cu lead-free solder alloy, both as bulk and nanoparticles, was investigated. The nanoparticles were manufactured using the self-developed consumable-electrode direct current arc (CDCA) technique. The melting temperature of the nanoparticles, with an average size of 30 nm, was found to be 213.9°C, which is approximately 10°C lower than that of the bulk alloy. The developed CDCA technique is therefore a promising method to manufacture nanometer-sized solder alloy particles with lower melting temperature compared with the bulk alloy.