Wetting of Sn-Zn-Ga and Sn-Zn-Na Alloys on Al and Ni Substrate

Abstract

Wetting of Al and Ni substrate by Sn-Zn eutectic-based alloys with 0.5 (wt.%) of Ga and 0.2 (wt.%) of Na was studied using the sessile drop method in the presence of ALU33 Ò flux. Spreading tests were performed for 60 s, 180 s, and 480 s of contact, at temperatures of 503 K, 523 K and 553 K (230°C, 250°C, and 280°C). After cleaning the flux residue from solidified samples, the spreading areas of Sn-Zn0.5Ga and Sn-Zn0.2Na on Al and Ni substrate were determined. Selected, solidified solder-pad couples were cross-sectioned and subjected to scanning electron microscopy with energy dispersive spectroscopy, x-ray diffraction study and synchrotron measurements of the interfacial microstructure and identification of the phases. The growth of the intermetallic Ni 5 Zn 21 phase layer was studied at the solder/Ni substrate interface, and the kinetics of the formation and growth of the intermetallic layer were determined. The formation of interlayers was not observed on the Al pads. On the contrary, dissolution of the Al substrate and migration of Alrich particles into the bulk of the solder were observed.

Structure and properties of Sn-Cu lead-free solders in electronics packaging

“…These initiatives provide a good opportunity for the development of new lead-free solder. Hence Sn-base lead-free solders, including Sn-Ag [8], Sn-Bi [9], Sn-Cu [10], Sn-In [11], Sn-Sb [12] and Sn-Zn [13] have become the potential candidates for Sn-Pb solder replacement.…”

The influence of Li on the thermophysical properties of liquid Ga–Sn–Zn eutectic alloys

“…Similarly for the previously investigated Al addition [20] the density values decrease with higher amount of Al, in the case of Li, the lowest density value was observed for 0.1 (wt%) of Li. The density value of elemental Li is equal to 0.506 (g.cm −3 ) [31] and is one order of magnitude less than values for eutectic Ga-Sn-Zn 5.983 (g.cm −3 ) at a temperature of 573 K, which has a high impact on density results of the studied alloys. A trend of decreasing density with Li content, such as for eutectic ZnAl with Li additions [25] was observed.…”

Interfacial Phenomena between Liquid Ga-Based Alloys and Ni Substrate

“…Moreover, the Gibbs free energy is much higher compared to the Ga-Ni phase, confirmed by the absence of Ni-Zn precipitates from the microstructure. The phase from the Ni-Zn system was observed in the case of soldering Ni substrate with Sn-Zn alloys, 29 and with increasing soldering time. The IMC from the Ni-Zn system has the lowest Gibbs free energy, and the start of the formation of an IMC from the Ni-Sn system is connected to the amount of Zn present.…”

“…Wetting tests 22 were performed for eutectic Ga-Sn-Zn alloys 23 86.3, 90.15 of Ga, 6.64 of Sn and 3.21 of Zn (at.%) corresponding to 86.3, 10.8 and 2.9 (wt.%), on Ni substrate (purity 99.99% and 250 lm thickness) using the sessile drop method. For this experiment, 15 9 20 mm sheets of Ni were used, with a drop 2-3 mm in diameter on top of the alloy.…”

“…28 According to, 27 there is no information about Ga 7 Ni 3 , which would allow Gibbs free energy to be calculated. While wetting the Ni substrate with eutectic Ga-Sn-Zn alloy, it became possible that a phase from the Ni-Zn system 22 would occur. Moreover, the Gibbs free energy is much higher compared to the Ga-Ni phase, confirmed by the absence of Ni-Zn precipitates from the microstructure.…”