Morphological and Structural Properties of Sn-Bi Lead-Free Solder in 6 M Potassium Hydroxide

Abstract

Sn-based lead-free solder alloys have been explored extensively as an alternative to the conventional Sn–Lead solder alloys. While the miniaturization of electronic devices and the growth of appliance area, the corrosion resistance of solder alloys play a crucial element in the reliability of electronic devices in a prolonged period of service. This paper determines the corrosion effect of Sn-Bi solder lead-free solder, particularly immersed in 6 M potassium hydroxide. Morphological and elemental analyses show the formation of oxides on the surface after immersion using a scanning electron microscope, dispersive energy X-ray and X-ray diffraction. Sn matrix in plateau indicated dark contrast while Bi-rich in the lamellar eutectic structure indicated in light contrast appearance. In addition, phase and elemental analyses revealed the formation of mixed corrosion products of SnO, SnO2 and Bi2O3 on the surface after testing. This finding provides some clarifying the corrosion progress of lead-free solder alloys