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
2019 ◽  
Vol 24 (4) ◽  
pp. 51-58
Author(s):  
Le Hong Quan ◽  
Nguyen Van Chi ◽  
Mai Van Minh ◽  
Nong Quoc Quang ◽  
Dong Van Kien

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.


2009 ◽  
Vol 50 (11) ◽  
pp. 2532-2540 ◽  
Author(s):  
Keitaro Horikawa ◽  
Hiroaki Okada ◽  
Hidetoshi Kobayashi ◽  
Wataru Urushihara

1994 ◽  
Vol 353 ◽  
Author(s):  
Fumio Matsuda ◽  
Ryutaro Wada ◽  
Kazuo Fujiwara ◽  
Ai Fujiwara

AbstractAs a sequence of studies to evaluate the quantity of gas evolution from low/intermediate level waste repositories,hydrogen gas evoluted from corrosion of carbon steel in simulated repository environment was evaluated by laboratory experiments. The experimental results on the hydrogen gas evolution both in air purging condition simulated oxidizing environment and nitrogen purging condition simulated reducing environment, are summarized as follows.(1)Hydrogen gas evolution enough to analyze quantitavely by gas chromatography (>5ppm) has been recognized under almost all test conditions except reducing equilibrium cement water.(2)Effects of purging gas (air,nitrogen) on the hydrogen gas evolution and the corrosion rate calculated from weight loss were air purge > nitrogen purge. On the other hand, the contribution ratio of hydrogen evolution reaction in corrosion rate was nitrogen purge > air purge.(3)Effects of test solution on the hydrogen evolution rate were as fo11ows. • Air Purge :Equilibrium Bentonite Water ≈ Equilibrium Cement Water > Synthetic Sea Watert• N2 Purge:Synthetic Sea Water > Equilibrium Bentonite Water >> Equilibrium Cement Water(4)No distinct effect of crevice geometry of test specimen on hydrogen evolution rate was recognized. Only under the reducing equilibrium cement water, however, the increase of hydrogen evolution was confirmed after the immersion of several hundred hours.(5)Hydrogen evolution rates tended to decrease with testing time except in the reducing equilibrium cement water.(6)No distinct difference of hydrogen evolution rate between steels (SPHC, SPCC) was observed.


2009 ◽  
Vol 54 (26) ◽  
pp. 6472-6478 ◽  
Author(s):  
Alessandro Benedetti ◽  
Luca Magagnin ◽  
Francesca Passaretti ◽  
Elisabetta Chelossi ◽  
Marco Faimali ◽  
...  

2019 ◽  
Vol 123 (39) ◽  
pp. 24146-24155 ◽  
Author(s):  
L. C. Yule ◽  
V. Shkirskiy ◽  
J. Aarons ◽  
G. West ◽  
C. L. Bentley ◽  
...  

Author(s):  
Roy Johnsen ◽  
Ba˚rd Nyhus ◽  
Stig Wa¨stberg

There has been an increasing trend in the use of stainless steel alloys instead of carbon steel for subsea flowlines and production systems during the last 15 years in the oil industry. Even if this normally is a more robust solution compared to the use of carbon steel insofar as internal corrosion problems are concerned, the use of stainless steels has led to leakage, production shutdown and expensive repair work. The reported failures were associated with hydrogen entrapment resulting from welding and/or external cathodic protection (CP), combined with a certain stress/strain level. Atomic hydrogen entering the alloy can weaken the mechanical strength of the alloy, cause cracks and destroy the integrity of equipment or a system. Such failures attributed to hydrogen induced stress cracking (HISC) are clearly not acceptable from the perspective of safety, environmental hazard and cost. Leading oil and engineering companies and supplier industry have pointed out HISC as one of the major obstacles against safe operation of stainless steel subsea pipelines and production systems. It is important for the oil industry to have design guidelines and reliable test method(s) for qualification and safe utilization of subsea pipelines and components made from the actual stainless steels. This paper describes a test method that has been developed through a Joint Industry Project (JIP) executed by SINTEF and Det Norske Veritas (DNV) with support from leading oil companies and material suppliers. The method has been qualified for use on 13% Cr super martensitic (SMSS) and 22% Cr / 25% Cr duplex stainless steels (DSS/SDSS). The link to DNV-RP-F112 [1] will also be described.


Sign in / Sign up

Export Citation Format

Share Document