Publication: Corrosion behavior of sn-9zn solder in 6.0 m koh electrolyte
Loading...
Date
2009-05-01
Authors
Baharudin, Rosmazila
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This research investigated the wetting behavior of Sn-9Zn solder at different reflow temperatures using spreading tests, with measured the spreading area and wetting angle of the solder on Cu substrate. Open circuit potential and potentiodynamic polarization tests are performed, to further understanding of the corrosion potential and polarization behavior of the solder in 6.0 M KOH electrolyte. Galvanic test also performed to study the galvanic corrosion behavior between the solder and copper substrate in 6.0 M KOH electrolyte. The Sn-9Zn solder show good wettability on Cu substrate above temperature 200 °C, where wettability of Sn-9Zn solder increase with increasing temperature. The corrosion potential of Sn-9Zn solder in 6.0 M KOH solution is at around -1000 V. The Sn-9Zn exhibit two passivity platforms when polarized in 6.0 M
KOH electrolyte. The first passivation is due to the formation of ZnO, meanwhile the second passivation is due to the formation of SnO. The Sn-9Zn solder shows the valueof Ecorr at -1.357 V, and the Icorr value at 2.32E-04 A/cm2. The corrosion rate of Sn- 9Zn solder is 5.764 mm year-1. FESEM and EDX analysis were performed after corrosion test to evaluate the corrosion product. The galvanic current densities of Sn- 9Zn solder with respect to Cu in 6.0 M KOH solution decrease with increasing time, and remain constant after 1500 s at value close to 0 A/cm2. The corrosion product formon the surface of Cu and Sn-9Zn solder, where on the Sn-9Zn solder surface SnO and ZnO are formed. Meanwhile CuO are formed on surface the Cu.