Evaluation of the uniform current density assumption in cathodic protection systems with close anode-to-cathode arrangement

2009 ◽  
Vol 61 (4) ◽  
pp. 338-342 ◽  
Author(s):  
S. Martinez
Keyword(s):  
Current Density ◽  
Cathodic Protection ◽  
Protection Systems ◽  
Density Assumption ◽  
Uniform Current

scholarly journals Features of Russian regulatory framework governing cathodic protection of heating networks against external corrosion in the ground

2019 ◽  
Vol 140 ◽  
pp. 05004
Author(s):  
Aleksandr Kalyutik ◽  
Vladimir Kiselev ◽  
Evgenij Ruzich ◽  
Andrey Kibarin
Keyword(s):  
Comparative Analysis ◽  
Current Density ◽  
Cathodic Protection ◽  
Regulatory Framework ◽  
Degree Of Protection ◽  
Protection Systems ◽  
Current Value ◽  
External Corrosion ◽  
Heating Networks

A comparative analysis of domestic and foreign documents governing the design of cathodic protection systems has been carried out. The main parameters for evaluating the effectiveness were selected: “protective current density”, “protective current value” and “indicators characterizing the degree of protection against corrosion in the presence of cathodic protection”. As a result, the need for improving the domestic system for designing cathodic protection installations was established. First of all, attention should be paid to the decrease in protective current, protective current density and criteria for determining the need for cathodic protection.

Evaluation of Designs of Shipboard Cathodic Protection Systems Using Boundary Element Modelling Technique

2011 ◽  
Author(s):  
Yueping Wang
Keyword(s):  
Boundary Element ◽  
Cathodic Protection ◽  
Modelling Technique ◽  
Hull Form ◽  
Corrosion Failure ◽  
Element Modelling ◽  
Protection Systems ◽  
Uniform Current ◽  
Impressed Current ◽  
Cathodic Protection System

Boundary element modelling technique was used to evaluate the performance of the underwater hull impressed current cathodic protection (ICCP) system of a steel-hulled vessel, as part of an investigation of the corrosion failure of the steel hull near the ICCP anodes. The same technique was also used to evaluate the designs of an alternate sacrificial anode cathodic protection system. The modelling results indicated that the existing ICCP system was capable of providing adequate cathodic protection to the underwater hull and appendages if the current demand is less than 2.4 A. Small anode size was found to have a profound effect on the potentials immediately adjacent to the anode, stressing the need for an effective, intact anode shield. Application of paint coating on the bronze propellers could substantially reduce the current demand from the anodes, resulting in less negative potentials adjacent to the anodes. The modelling results also showed that the anode design adopted from a vessel of similar size (<5% difference in all dimensions), which consists of 8 hull mounted aluminum anodes and 4 rudder zinc anodes, would provide adequate cathodic protection for the underwater hull structures of the existing vessel for more than 3 years. The performance of a modified anode placement was also studied in comparison with that of the original anode placement. The results indicated that the anodes in the modified anode placement would not only contribute more uniform current than the anodes in the original anode placement, but also result in the potential profiles that have less variations along the hull form. This modified anode placement would potentially result in a longer service life of the anodes.

Basic properties of anodized porous silicon formed under uniform current density

1994 ◽  
Vol 77 (4) ◽  
pp. 97-105
Author(s):  
Hidekazu Aoyagi ◽  
Akira Motohashi ◽  
Akira Kinoshita ◽  
Tomoyoshi Aono ◽  
Akinobu Satoh
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Basic Properties ◽  
Uniform Current

Corrosion Behaviour of Unprotected Weldments in Marine Environments

CORROSION ◽  
10.5006/3824 ◽  
2021 ◽  
Author(s):  
Nicholas Senior ◽  
Lawrence Parkinson ◽  
Magdalene Matchim ◽  
Jennifer Collier ◽  
Hung-Wei Liu
Keyword(s):  
Weld Metal ◽  
Cathodic Protection ◽  
Corrosion Behaviour ◽  
Coast Guard ◽  
Metal Corrosion ◽  
Corrosion Performance ◽  
Accelerated Corrosion ◽  
Potential Safety ◽  
Protection Systems ◽  
Welding Consumables

In the absence of protective measures such as paint or cathodic protection systems, steel weldments, immersed in seawater, are expected to corrode freely. This is particularly true for the ice breakers serving the Canadian Coast Guard, where, in the course of operations, paint is scoured from the vessel hulls and cathodic protection systems were not installed. However, the weldments do not corrode uniformly. In some cases, the weld itself corrodes rapidly and requires regular replacement. At the other extreme, the heat-affected zones corrode instead—a potential safety and integrity concern. The morphology of ice breaker weldment corrosion has altered over the last few decades and this has been attributed to changes in welding consumables and processes. The current study is an investigation into the corrosion characteristics of weldments with a particular focus on the compositional differences between weld metal and hull plate steels. A method has been developed for numerically describing the corrosion of weldment regions (plate steel, heat-affected zones, weld cap passes and weld re-heated zones) arising from an accelerated corrosion test. This in turn enabled the development of an equation that predicts weldment corrosion performance based entirely on material composition. This permits selection of welding consumables that are anticipated to give good corrosion performance, avoiding the extremes of rapid weld metal corrosion and preferential heat-affected zone attack.

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