Interfacial interaction of solid nickel with liquid Pb-free Sn–Bi–In–Zn–Sb soldering alloys

• Published in: Journal of alloys and compounds Vol. 460; no. 1; pp. 337 - 352
• Main Authors: Dybkov, V.I., Khoruzha, V.G., Sidorko, V.R., Meleshevich, K.A., Samelyuk, A.V., Berry, D.C., Barmak, K.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 28-07-2008; Elsevier
• Subjects: Applied sciences; Brazing. Soldering; Dissolution kinetics; Exact sciences and technology; Joining, thermal cutting: metallurgical aspects; Metals. Metallurgy; Ni 3Sn 4 layer growth rate; Nickel; Nickel-to-solder joint strength; Pb-free soldering alloys; Ni 3Sn 4 layer growth rate; Nickel; Pb-free soldering alloys; Nickel-to-solder joint strength; Dissolution kinetics; Growth rate; Solubility; Temperature effect; Transition metal; Tensile strength; Tin base alloys; Arrhenius equation; Lead free solder; Kinetics; Interface reaction; Diffusion coefficient; Rate constant; Mathematical model; Soldering; Elongation (mechanics); Ni3Sn4 layer growth rate
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2007.06.056

The dissolution process of nickel in liquid Pb-free 87.5% Sn–7.5% Bi–3% In–1% Zn–1% Sb and 80% Sn–15% Bi–3% In–1% Zn–1% Sb soldering alloys has been investigated by the rotating disc technique at 250–450
°C. The temperature dependence of the nickel solubility in soldering alloys obeys a relation of the Arrhenius type
c
s
=
4.94
×
10
2
exp(−39500/
RT)% for the former alloy and
c
s
=
4.19
×
10
2
exp(−40200/
RT)% for the latter, where
R is in J
mol
−1
K
−1 (8.314
J
mol
−1
K
−1) and
T is in K. Whereas the solubility values differ considerably, the dissolution rate constants are rather close for these alloys and fall in the range (1–9)
×
10
−5
m
s
−1 at disc rotational speeds of 6.45–82.4
rad
s
−1. Appropriate diffusion coefficients vary from 0.16
×
10
−9 to 2.02
×
10
−9
m
2
s
−1. With both alloys, the Ni
3Sn
4 intermetallic layer is formed at the interface of nickel and the saturated or undersaturated melt at dipping times of 300–2400
s. The other Ni–Sn intermetallic compounds are found to be missing. A simple mathematical equation is proposed to evaluate the Ni
3Sn
4 layer thickness in the case of undersaturated melts. The tensile strength of the nickel-to-alloy joints is 94–102
MPa, with the relative elongation being 2.0–2.5%.