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Investigation of stone‐hard‐soil formation from AC corrosion of cathodically protected pipeline
Author(s) -
Junker Andreas,
Belmonte Louise J.,
Kioupis Nick,
Vendelbo Nielsen Lars,
Møller Per
Publication year - 2018
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.201709947
Subject(s) - calcite , cathodic protection , corrosion , materials science , metallurgy , precipitation , cathode , coating , spectroscopy , mineralogy , chemistry , composite material , electrochemistry , electrode , physics , quantum mechanics , meteorology
A stone‐hard‐soil structure was observed on a metallic pipeline under cathodic protection and subject to alternating current corrosion at a coating defect. Using X‐ray diffraction, energy dispersive X‐ray spectroscopy, ion‐chromatography and inductively coupled plasma optical emission spectroscopy, the stone‐hard‐soil was characterized as being enriched in NaCl. Local alkalization following the cathode reactions caused precipitation of calcite, believed to be partly responsible for the stability of the structure. Very close to the corrosion site at the epicenter, calcite and quartz was depleted, possibly owing to an extremely high pH. Formation of cement‐like minerals and corrosion products is observed.