Electrochemical Study of Calcareous Deposit Formation in Simulated Soil Solution under Cathodic Protection

Cathodic protection induces the formation of a calcareous layer has been shown to improve metal protection against corrosion by reducing the oxygen diffusion on the metal surface. The present study focuses on the electrochemical scaling induced by the application of cathodic polarisation. A combinat...

Full description

Saved in:
Bibliographic Details
Published in:Key engineering materials 2019-09, Vol.821, p.307-312
Main Authors: Mjwana, Phumlani, Refait, Philippe, Jeannin, Marc, Obadele, Babatunde A., Olubambi, Peter
Format: Article
Language:English
Subjects:
Allotropy
Aragonite
Brucite
Calcite
Calcium carbonate
Cathodic polarization
Cathodic protection
Chemical Sciences
Computer simulation
Corrosion prevention
Electrochemical impedance spectroscopy
Electrode polarization
Electrolytes
Engineering Sciences
Inhomogeneity
Magnesium hydroxide
Metal surfaces
Physics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Cathodic protection induces the formation of a calcareous layer has been shown to improve metal protection against corrosion by reducing the oxygen diffusion on the metal surface. The present study focuses on the electrochemical scaling induced by the application of cathodic polarisation. A combination of non-invasive in-situ electrochemical techniques and electrochemical impedance spectroscopy was used. Metal/electrolyte interface behaviour was studied using voltammetry to determine the controlling anodic and cathodic reactions. One-week long experiments were conducted. Applied potential –1.2 VSCE was shown to enable the formation of CaCO3 allotropes calcite and aragonite, and brucite due to increased interfacial pH which resulted in the formation of hydrogen at the electrode surface. Time constants from bode plots for applied potential –1.2 VSCE also illustrated the inhomogeneity of the calcareous layer. Modelling of polarisation curves illustrated a “passivation” phenomenon which resulted from formation of hydroxyl cations. This was further validated by bode plots with the added information on the diffusion reaction process. High frequency behaviour showed a steady increase in the electrolyte resistance which may be attributed to the formation of the calcareous layer. Evidence of the initial Mg-gel porous layer, which precedes the formation of brucite, was found.
ISSN:1013-9826
1662-9795
1662-9795
DOI:10.4028/www.scientific.net/KEM.821.307