Premium
The corrosion mechanism initiation of a 75Sn–25Pb coating on a low‐carbon steel sample in HCl environments
Author(s) -
Lequien Florence,
Moine Gervaise,
Lequien Arnaud,
Neff Delphine
Publication year - 2021
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.202112336
Subject(s) - tin , corrosion , chemistry , carbon steel , chloride , electrolyte , inorganic chemistry , coating , precipitation , carbon fibers , metallurgy , materials science , electrode , physics , organic chemistry , meteorology , composite number , composite material
The corrosion of a 75Sn–25Pb coating on low‐carbon steel exposed to a vapor/condensate phase over a 1 mol/L HCl solution has been studied. The corrosion mechanism initiation was based on several steps. The presence of CO 2 and lead involves the precipitation of cerussite PbCO 3 crystals. Overtime, the cerussite evolved and transformed into PbCl 2 . This transformation was not direct and involved the creation of reaction intermediates whose chemical composition was variable. In parallel, tin formed oxides that were not stable in the HCl solution. These oxides dissolved and led to the formation of an electrolyte concentrated in Sn 2+ . When tin ions' saturation was reached, tin precipitated to form abhurite, Sn 21 Cl 16 (OH) 14 O 6 , or hydrated tin chloride, SnCl 2 .2H 2 O. This study highlighted the particularity of the corrosion mechanism. It also showed that the presence of tin promoted the oxidation of lead and consequently the formation of cerussite.