Comparative corrosion behaviour of different Sn-based solder alloys

Abstract

Sn-Pb solders, particularly Sn-37 %Pb eutectic alloy, have been widely used as low temperature joining alloys for some time. However, the restriction of Pb use in industry has been strongly promoted to protect the environment and establishing a Pb-free solder has become a critical issue and an important task for material engineers. New solders must fulfil several requirements; in particular they must be corrosion resistant. In the present work, the corrosion behaviour of five Pb-free solders was studied in a 0.1 M NaCl aqueous solution by means of polarization measurements (corrosion potential measurements, potentiodynamic polarization curves and linear polarization resistance tests), and compare to that of a conventional Sn-37 %Pb solder alloy and pure Sn. The results show that the Sn-3.5 %Ag-0.9 %Cu, Sn-3.5 %Ag and Sn-0.7 %Cu solders have the best resistance to localized as well as to general corrosion, similar to that obtained for the Sn-37 %Pb solder and pure Sn. The Sn-57 %Bi solder has poorer corrosion properties but its behaviour is still acceptable, because it passivates and shows a relatively low corrosion rate. In all these cases the corrosion resistance is good due to the content of noble elements (Ag, Cu, Pb and Bi) in the alloys. On the other hand, the Sn-9 %Zn is definitely the one that exhibits the worst behaviour, not only to localize but also to general corrosion, due to the addition of a less noble material to the Sn matrix.

On the Effects of Atmospheric Particles Contamination and Humidity on Tin Corrosion

“…The composition of atmospheric particles in an electrolyte solution will have an effect on both the anodic dissolution of tin, and the stability of tin corrosion products in electrolyte; thereby it will have an effect on probability and rate of dendrite formation. The corrosion behavior of Sn-based solder alloys in NaCl and > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < acid electrolytes was also reported [53], [54]. Overall comparison of corrosion potential and corrosion current density between above literature studies and our current study indicates similar corrosion rates, although different influence on passivation and pitting of tin was observed.…”

Corrosion and Leaching Behaviours of Sn-0.7Cu-0.05Ni Lead-Free Solder in 3.5 wt.% NaCl Solution

“…To study further the potential of Sn-0.7Cu 0.05Ni solder alloy, there is a need to assess its corrosion behaviour as it is an important factor to consider in formulating new solder materials [16]. The presence of moisture and corrosive salts/ions triggers the corrosion activity of these solder metals affecting the form, fit, and function of the electronic device [17,18].…”

Microstructural and Creep Characterization of Sn-0.7Cu and Sn-0.7Cu-xBi Lead-free Solders for Low Cost Electronic Applications

“…Lead-free solder alloys are typically Sn-based alloys due to the high corrosion resistance and good solderability of tin (Sn) [1]. Solder alloys based on the eutectic Sn-Ag and Sn-Cu alloy systems have been found to be amongst the most favorable leadfree alternatives [2][3] [4] [5][6] [7].…”