Corrosion behavior assessment of tin-lead and lead free solders exposed to fire smoke generated by burning polyvinyl chloride

• Published in: Materials chemistry and physics Vol. 212; pp. 298 - 307
• Main Authors: Li, Qian, Liu, Xufei, Lu, Shouxiang
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.06.2018; Elsevier BV
• Subjects: Corrosion; Fire smoke; Lead free; Lead free solders; Microstructure; Polyvinyl chloride; Smoke; Solders; Tin-lead solder; Tin-lead solder; Fire smoke; Corrosion; Microstructure; Lead free solders
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.03.057

The corrosion characteristics of tin-lead and three lead free solders (Sn-0.7Cu, Sn-3.0Ag and Sn-3.0Ag-0.5Cu) exposed to fire smoke generated from polyvinyl chloride (PVC) were comparatively investigated through weight loss method and surface characterization techniques. Results show that the corrosion rates of each of four examined solders rise with the increase of smoke concentrations over the concentration range from 20 g/m3 to 140 g/m3. Sn-37Pb solder exhibits the optimal corrosion resistance, while lead free Sn-3.0Ag-0.5Cu solder has much poorer corrosion resistance in comparison with the former, even with the Sn-0.7Cu and Sn-3.0Ag alloys. As indicated by SEM and XRD, the corrosion resistance of these lead free solders may be related to their microstructure. When the alloys involve more intermetallic compounds, the more larger cathode areas are presented, the weaker the corrosion resistance seems to be. Further, XRD and Raman spectrum reveal that SnO and PbCl2 are the main corrosion products of Sn-37Pb solder, while those of lead free solders primarily consist of Sn21Cl16(OH)14O6 and SnO. Accordingly, the corrosion mechanisms are further analyzed. [Display omitted] •The corrosion characteristics of tin alloys exposed to polyvinyl chloride fire smoke atmosphere are investigated.•Sn-37Pb solder shows better corrosion resistance than lead free solders (Sn-0.7Cu, Sn-3.0Ag and Sn-3.0Ag-0.5Cu).•Sn-3.0Ag-0.5Cu solder exhibits the poorest corrosion resistance.•The corrosion resistance of lead free solders is related to their microstructure.•The mechanisms of both the corrosion and the corrosion resistance differences among different solders are analyzed.