Cathodic Protection Modeling of a Covered and Uncovered Steel Immersed in Seawater: Corrosion Characterization

Abstract CDA 710 is a cupro-nickel alloy having high resistance to seawater corrosion and good stress-rupture properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Cu-215. Producer or source: Anaconda American Brass Company.

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

Practice of Anticorrosive Protection ◽

10.31615/j.corros.prot.2019.94.4-6 ◽

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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