Open AccessEffects of the Different Solid Deposits on the Corrosion Behavior of Pure Fe in Water Vapor at 500°C
Author(s) -
Yinan Tang,
Xinwang Shen,
Zhihong Liu,
Ying Li
Publication year - 2020
Publication title -
scanning
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.359
H-Index - 47
eISSN - 1932-8745
pISSN - 0161-0457
DOI - 10.1155/2020/6280725
Subject(s) - materials science , analytical chemistry (journal) , electrochemistry , chemistry , chromatography , electrode
A comprehensive corrosion investigation of pure Fe in an environment of solid sodium salt deposit (i.e., NaCl or Na 2 SO 4 ) with mixtures of H 2 O and O 2 at 500°C was conducted by mass gain measurement, X-ray diffraction (XRD), scanning electron microscope (SEM), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results showed that corrosion rates were accelerated with solid NaCl or Na 2 SO 4 deposit due to their reaction with the formed protective scale of Fe 2 O 3 and subsequently resulted in its breakdown. The corrosion rate of pure Fe with solid NaCl is higher than that with solid Na 2 SO 4 because of the lower activation energy ( E a ) for chemical reaction of Fe in solid NaCl+H 2 O+O 2 (i.e., 140.5 kJ/mol) than that in solid Na 2 SO 4 +H 2 O+O 2 (i.e., 200.9 kJ/mol). Notably, the electrochemical corrosion rate of pure Fe with solid NaCl deposit, 1.16 × 10 −4 A/cm 2 , was a little lower than that with solid Na 2 SO 4 deposit.