scholarly journals Performance Assessment of Magnesium Anodes Manufactured by Sintering Process

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 406
Author(s):  
Judith A. Sanmiguel-May ◽  
Ruth López-Alcantara ◽  
Erick A. Juárez-Arellano ◽  
José T. Pérez-Quiroz ◽  
Antonio Contreras ◽  
...  

This work shows the performance of cathodic protection systems formed by an API (American Petroleum Institute) X52 steel exposed to seawater and coupled with galvanic anodes of Mg, Mg-1Cr, and Mg-1Nb fabricate by sintering technique at a temperature of 500 °C. Potential monitoring indicates that X52 steel of the three systems remained in the protection zone. Mg-Nb/X52 system showed the more stable potentials since the first day; the recorded values remained between –1.0 and –1.1 V vs SCE (saturated calomel electrode) during the seven days of exposure time. Current density records show that Mg/X52 system had the most stable values, while the other two systems (Mg-Cr/X52 Mg-Nb/X52,) had current fluctuations. The Mg-X52 system recorded the most negative potential values, which can be attributed to a greater magnitude and a better distribution of the cathodic protection current. However, the Mg-Nb/X52 system had a better result because the current drained by the system was constant throughout the experiment.

2021 ◽  
Vol 106 ◽  
pp. 44-53
Author(s):  
Kailong Zhou ◽  
Xin Chen ◽  
Min Wu ◽  
Yosuke Nakanishi ◽  
Weihua Cao ◽  
...  

CORROSION ◽  
10.5006/3824 ◽  
2021 ◽  
Author(s):  
Nicholas Senior ◽  
Lawrence Parkinson ◽  
Magdalene Matchim ◽  
Jennifer Collier ◽  
Hung-Wei Liu

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.


Author(s):  
Jacob Brink Jansson ◽  
Ruth Sørensen ◽  
Kirsten Riis

Cathodic protection is a very well-known method of preventing or stopping reinforcement corrosion and thereby extending the service life of reinforced concrete civil structures. However, a number of factors, which among others are design, materials and components, installation methods, quality of workmanship, and operation and maintenance of the cathodic protection system, have influence on the functionality and effectivity of the cathodic protection system. The optimum design that fulfils the Client''s requirements to cost, traffic disruption, service life, etc. shall be determined in accordance with the structure layout and the ability of the Client''s organisation to conduct operation and maintenance. It is critical to ensure that all components are installed properly to achieve the expected service life of the system. Regular and correct operation and maintenance is also crucial to ensure the functionality and effectivity system.


CORROSION ◽  
1963 ◽  
Vol 19 (2) ◽  
pp. 59t-68t ◽  
Author(s):  
W. J. SCHWERDTFEGER ◽  
RAUL J. MANUELE

Abstract Three steel specimens were continuously exposed in the laboratory for almost 5 years in city water to which was added 3 percent by weight of sodium chloride. Two of these specimens were under continuous cathodic protection, one by current from a zinc anode, and the other by current from a rectifier through a carbon anode. The third specimen was left to corrode freely. As a result of the cathodic protection, carbonates and silicates formed protective coatings which eventually reduced the current density required for protection from about 5 to 0.02 ma/sq ft. A coated specimen, after being without protective current for 32 days (including 12 days out of the salt water), required only 0.3 ma/sq ft for initial protection. The instantaneous corrosion rates on the coated specimens (scratched and unscratched) while without protective currents were measured by changes-in-slope (breaks) in polarization curves. The currents at which breaks occurred in the cathodic curves were found to be related to ΔV/ΔI values from the curves, which values in turn bore a relation to the corrosion rates as measured by weight loss.


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