Development of lead-free Sn–0.7Cu/Al₂O₃nanocomposite solders with superior strength

Abstract

Sn–0.7Cu is a low cost lead-free solder alloy that is targeted to replace the eutectic Sn–Pb solder. The main limitation of this alloy is its poor strength characteristics. Accordingly, this study aims at improving the mechanical properties of Sn–0.7Cu using Al2O3 particulates in the nanolength scale. The development of nanocomposite solders was accomplished using the powder metallurgy technique incorporating microwave sintering. Results of characterization studies conducted on the extruded samples revealed the presence of equiaxed grains, Cu6Sn5 phase and pores. The mechanical properties (microhardness, 0.2%YS and UTS) increase with the increasing presence of reinforcement with the best tensile strength realized for the composite containing 1.5% alumina that far exceeds the strength of the eutectic Sn–Pb solder.

Synthesis and Properties of Pulse Electrodeposited Lead-Free Tin-Based Sn/ZrSiO4 Nanocomposite Coatings

“…[7,8,[26][27][28][29] There are several studies on composite solders in the past with a variety of reinforcement materials, such as Al 2 O 3 , TiO 2 , ZrO 2 , Si 3 N 4 , SiC, SnO 2 , ZnO, CeO 2 , La 2 O 3 , to reinforce the solder matrix and improve the microstructural properties. [5,[10][11][12][13][30][31][32][33][34][35][36] However, limited studies exist in literature about the effect of ceramic nanoparticles on the evolution of Sn whisker growth after aging and its mitigation. It is also noticed that ZrSiO 4 has been rarely used to reinforce a solder matrix, which can be a potential candidate for designing a nanocomposite solder.…”

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The Sn-based ZrSiO 4 nanocomposite coatings have been synthesized by pulse co-electrodeposition technique from an aqueous electrolyte containing SnCl 2 AE2H 2 O, C 6 H 17 N 3 O 7 , Triton X, and varying amounts of nano-sized ZrSiO 4 particles (0,5,10,15,20,25,30, and 35 g/L). As-deposited films have been analyzed using X-ray diffraction, scanning electron microscope equipped with an energy dispersive X-ray spectrometer, and transmission electron microscope.

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Thermal and mechanical properties of Sn-Cu-Ni-XSiC composite solder

“…They found that the addition of nano ZrO2 also increased the microhardness properties of Sn-Ag alloy . Zhong and Gupta [15] also successfully prepared a nano-Al2O3 reinforced composite solder into Sn0.7Cu lead-free solder, and this composite solder has improved the mechanical properties as well. …”

Pulse Electrodeposition of Lead-Free Tin-Based Composites for Microelectronic Packaging

“…Most of the solder matrix composites are reinforced with ceramic particles like ZrO 2 , Al 2 O 3 , TiO 2 , SiC, Cu 2 O, SnO 2 , La 2 O 3 . [7,18,19,[21][22][23][24][25] The reinforcing particles suppress growth of intermetallic compounds (IMC) and provide uniform stress distribution in the matrix. [8,18,19] This method of nanotechnology would provide high strength and reliable solders for microelectronic packaging devices.…”