Influence of Cathodic Protection Parameters on Calcareous Deposit Formation

CORROSION ◽  
1988 ◽  
Vol 44 (12) ◽  
pp. 887-891 ◽  
Author(s):  
R. U. Lee ◽  
J. R. Ambrose
Keyword(s):  
Cathodic Protection ◽  
Deposit Formation ◽  
Calcareous Deposit

Carbon Steel Corrosion and Cathodic Protection Data in Deep North Atlantic Ocean

CORROSION ◽  
10.5006/3552 ◽  
2020 ◽  
Vol 76 (11) ◽  
Author(s):  
Erwan Diler ◽  
Nicolas Larché ◽  
Dominique Thierry
Keyword(s):  
Carbon Steel ◽  
Atlantic Ocean ◽  
Cathodic Protection ◽  
Cold Water ◽  
Potential Temperature ◽  
Natural Seawater ◽  
Cathodic Current ◽  
Deposit Formation ◽  
X Ray ◽  
Calcareous Deposit

Many parameters may influence the corrosion and the cathodic protection current demand in natural seawater. These are potential, temperature, dissolved oxygen content, biofilm and fouling activity, hydrostatic pressure, and calcareous deposit formation. In this study, the influence of the exposure depth on the corrosion, cathodic protection current demand, and nature of the calcareous deposit formed on carbon steel was investigated at 1,020 m and 2,020 m depth. For this purpose, a set of coupons, cathodic protection, and environmental sensors were exposed in Azores in the Atlantic Ocean for 11 months. The higher corrosion rate and current density observed at 1,020 m can be explained by the higher temperature and oxygen diffusion. The cathodic current demand decrease with time can be attributed to the calcareous deposit formation. The current densities after 11 months are in agreement with the literature with 143 mA/m2 and 124 mA/m2 at 1,020 m and 2,020 m depth. Calcareous deposits formed, characterized by Raman spectroscopy, x-ray diffraction, and scanning electron microscopy/electron dispersive x-ray spectroscopy, highlight (i) the favored formation of calcite and hydrocalcite at the expense of aragonite in deep and cold water, (ii) the presence of a thin deposit after 11 months, (iii) the decrease of the Ca/Mg ratio with immersion depth, (iv) the presence of CaMgCO3 compounds, and (v) a higher decrease of the current demand with time in deep water, suggesting the formation of a more protective deposit. The capacity for aluminum-gallium and aluminum-indium galvanic anode were in agreement with the literature for long-term exposures.

Kaolinite influence on calcareous deposit formation

2009 ◽  
Vol 55 (1) ◽  
pp. 196-203 ◽  
Author(s):  
C. Rousseau ◽  
F. Baraud ◽  
L. Leleyter ◽  
M. Jeannin ◽  
O. Gil
Keyword(s):  
Deposit Formation ◽  
Calcareous Deposit

Calcareous deposit formed under cathodic protection in the presence of natural marine sediments: A 12 month experiment

2010 ◽  
Vol 52 (6) ◽  
pp. 2206-2218 ◽  
Author(s):  
C. Rousseau ◽  
F. Baraud ◽  
L. Leleyter ◽  
M. Jeannin ◽  
O. Gil
Keyword(s):  
Marine Sediments ◽  
Cathodic Protection ◽  
Calcareous Deposit

The study of the electrochemical properties of zinc-rich coating on the base of water sodium silicate

2019 ◽  
Vol 24 (4) ◽  
pp. 51-58
Author(s):  
Le Hong Quan ◽  
Nguyen Van Chi ◽  
Mai Van Minh ◽  
Nong Quoc Quang ◽  
Dong Van Kien
Keyword(s):  
Carbon Steel ◽  
Electrochemical Properties ◽  
Sodium Silicate ◽  
Cathodic Protection ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Electrical Contact ◽  
Electrochemical Impedance Spectra ◽  
Pure Zinc ◽  
Electric Circuits

The study examines the electrochemical properties of a coating based on water sodium silicate and pure zinc dust (ZSC, working title - TTL-VN) using the Electrochemical Impedance Spectra (EIS) with AutoLAB PGSTAT204N. The system consists of three electrodes: Ag/AgCl (SCE) reference electrode in 3 M solution of KCl, auxiliary electrode Pt (8x8 mm) and working electrodes (carbon steel with surface treatment up to Sa 2.5) for determination of corrosion potential (Ecorr) and calculation of equivalent electric circuits used for explanation of impedance measurement results. It was shown that electrochemical method is effective for study of corrosion characteristics of ZSC on steel. We proposed an interpretation of the deterioration over time of the ability of zinc particles in paint to provide cathodic protection for carbon steel. The results show that the value of Ecorr is between -0,9 and -1,1 V / SCE for ten days of diving. This means that there is an electrical contact between the zinc particles, which provides good cathodic protection for the steel substrate and most of the zinc particles were involved in the osmosis process. The good characteristics of the TTL-VN coating during immersion in a 3,5% NaCl solution can also be explained by the preservation of corrosive zinc products in the coating, which allows the creation of random barrier properties.

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