Corrosion behavior of Sn‐3.0Ag‐0.5Cu solder under different fire smoke atmospheres generated by burning polyvinyl chloride and polyethylene

Abstract

The corrosion characteristics of Sn‐3.0Ag‐0.5Cu solder under polyvinyl chloride (PVC) and polyethylene (PE) fire smoke atmospheres were investigated by weight loss method and surface characterization techniques. The corrosion kinetics results of 15‐day tests show that the mass loss of Sn‐3.0Ag‐0.5Cu solder in PE smoke is much lower than that in PVC smoke. The former shows no significant variation during the test. In contrast, the latter increases rapidly first and then presents a slow exponential increase. Microstructure analysis indicates that no obvious corrosion product appeared in PE smoke. Nevertheless, the corrosion products in PVC smoke grow larger first and then become smaller and denser. The possible growth process of corrosion products is that grain growth dominates the formation of the corrosion products at the initial stage and then the nucleation process is predominant. Furthermore, the corrosion mechanisms of Sn‐3.0Ag‐0.5Cu solder in the different fire smoke are also analyzed. Stannous oxide and stannic oxide are regarded as the corrosion products under both PE and PVC smoke atmospheres, while Sn21Cl16(OH)14O6 is only observed under PVC smoke atmosphere.