Open Circuit Potential Measurement of Sn-9Zn-xIn Lead Free Solders in 6 M KOH Electrolyte
1Center of Excellence Geopolymer & Green Technology (CEGeoGTech), Universiti Malaysia Perlis, Arau, Perlis, Malaysia
2Materials Engineering, Universiti Malaysia Perlis, Arau, Perlis, Malaysia
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Abstract : Corrosion properties of ternary Sn-9Zn-xIn (x = 1, 2, 3, 4, 5 and 6 wt. %) solders were studied by means of open circuit potential (OCP) measurement in 6Â M potassium hydroxide. The results are compared with the binary Sn-9Zn solder in order to assess the influence of In on the corrosion properties. The OCP and microstructural measurements reveal that the passivation ability of Sn-9Zn solder is progressively improved at the additions of 1-4 wt. % of In. The presence of massive grooves produced by the preferential dissolution of the enlarged Zn-rich phase restricts the protection offered by the passivation film of 5-6 wt. % of In. This contributes to the lower ultimate tensile strength for the solder joint after immersion in 6 M KOH.
Keywords : Corrosion,Sn-9Zn,Indium ,Potassium hydroxide,Mechanical properties,