scholarly journals ELECTRO-MECHANICAL BREAKDOWN MECHANISM OF PASSIVE FILM IN AC-RELATED CORROSION OF CARBON STEEL UNDER CATHODIC PROTECTION CONDITION

CORROSION ◽  
10.5006/1849 ◽  
2016 ◽  
Author(s):  
Andrea Brenna ◽  
Marco Ormellese ◽  
Luciano Lazzari
Keyword(s):  
Carbon Steel ◽  
Passive Film ◽  
Cathodic Protection ◽  
Breakdown Mechanism ◽  
Mechanical Breakdown

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.

Correlation between Electrical Properties of the Passive Film on Carbon Steel and Inhibition Efficiency by Phosphate and Nitrite Ions

2017 ◽  
Vol 80 (10) ◽  
pp. 621-633
Author(s):  
Maria Alejandra Frontini ◽  
Marcela Vázquez ◽  
María Beatriz Valcarce
Keyword(s):  
Carbon Steel ◽  
Electrical Properties ◽  
Passive Film ◽  
Inhibition Efficiency

Cathodic protection of carbon steel in natural seawater: Effect of sunlight radiation

2009 ◽  
Vol 54 (26) ◽  
pp. 6472-6478 ◽  
Author(s):  
Alessandro Benedetti ◽  
Luca Magagnin ◽  
Francesca Passaretti ◽  
Elisabetta Chelossi ◽  
Marco Faimali ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Cathodic Protection ◽  
Natural Seawater ◽  
Sunlight Radiation

Significance of Hydrogen Evolution during Cathodic Protection of Carbon Steel in Seawater

CORROSION ◽  
2007 ◽  
Vol 63 (9) ◽  
pp. 857-865 ◽  
Author(s):  
T. Okstad ◽  
Ø. Rannestad ◽  
R. Johnsen ◽  
K. Nisancioglu
Keyword(s):  
Carbon Steel ◽  
Hydrogen Evolution ◽  
Cathodic Protection

scholarly journals Study of the Fe(II-III) hydroxysalts transformation according to the pH and the concentration of the ions present

2018 ◽  
Vol 7 (5) ◽  
pp. 359-369
Author(s):  
Farida Termemil ◽  
Marwa Ahmed-Malek ◽  
Assia Bourouba ◽  
Mohamed-rida Benloucif
Keyword(s):  
Carbon Steel ◽  
Cathodic Protection ◽  
Iron Hydroxide ◽  
Green Rust ◽  
Corrosion Products ◽  
Water Molecules ◽  
Marine Environments ◽  
Sulphate Reducing Bacteria ◽  
Reducing Bacteria ◽  
Ordinary Steel

Sulphated green rust, GR (SO4 2- ), is one of the main corrosion products of carbon steel in marine environments. It is Fe (II)-Fe(III) hydroxylsalt in sheets, consisting of alternating layers of iron-hydroxide type Fe(OH)2 , loaded positively due to the presence of the cations Fe(III) and negative interlayers consisting of anions and water molecules. This compound is strongly associated with the metabolism of sulphate-reducing bacteria, and can also evolve under cathodic protection. Thus, recently, GR (CO3 2- ) has been detected in place of GR (SO4 2- ) on already corroded ordinary steel, newly subjected to cathodic protection. This presence is due to the pH and[SO4 2−] [HCO3 − ⁄ ] conditions imposed by the cathodic protection. In this paper, we chemically synthesize sulfated and carbonate green rust in a chlorinated medium; we then study their respective transformation according to the concentration [SO4 2- ] / [HCO3 - ] ratio and pH. Our results show that from a GR (SO4 2- ), GR (CO3 2- ) is formed from a pH ≥8.2 for [SO4 2- ] / [HCO3 - ] = 12 and without any change in pH for [SO4 2- ] / [HCO3 - ] <12. Whereas from GR (CO3 2- ), GR (SO4 2- ) is formed for [SO4 2- ] / [HCO3 - ] > 1 without any change in pH.

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