Effects of Titanium Combined with Aluminium on the Electrochemical Properties and Efficiency of Mg-Mn Anodes

2011 ◽  
Vol 264-265 ◽  
pp. 783-788
Author(s):  
E. Fadaei ◽  
M. Emamy ◽  
C. Dehghanian ◽  
M. Karshenas
Keyword(s):  
Electrochemical Properties ◽  
Cathodic Protection ◽  
Electrochemical Behavior ◽  
Titanium Content ◽  
Short Term ◽  
Electrochemical Tests ◽  
Sacrificial Anodes ◽  
Protection Systems ◽  
Work Samples ◽  
Magnesium Anode

Magnesium sacrificial anodes are widely used in cathodic protection systems. In the present work, samples of Mg-0.7% Mn- x% Al- y% Ti (x,y = 0-0.6) alloys were electrochemically characterized to evaluate their performance as magnesium sacrificial anodes. The experiments focused on the influence of aluminium and titanium contents on the electrochemical behavior and efficiency of anodes. Aluminium and titanium was used in different concentrations ranging from 0.15 to 0.60 at.%. Short-term electrochemical tests, ASTM G97-89, as well as polarization curves were performed to obtain electrochemical behavior and efficiency and to reveal any tendencies to be passive. It is shown that by increasing titanium content an improvement of electrochemical properties of magnesium anode such as current capacity and electrochemical efficiency can be obtained.

Navy Experimental Work with Cathodic Protection★

CORROSION ◽  
1956 ◽  
Vol 12 (3) ◽  
pp. 18-24 ◽  
Author(s):  
IRVING D. GESSOW
Keyword(s):  
Cathodic Protection ◽  
Corrosion Damage ◽  
High Resistivity ◽  
Sacrificial Anodes ◽  
Initial Cost ◽  
Protection Systems ◽  
Impressed Current ◽  
The Cost ◽  
Work Done ◽  
Polluted Waters

Abstract An account is given of work done by the Navy Bureau of Ships with cathodic protection of active and reserve ships. Because it is difficult to dissociate costs for maintenance and corrosion protection it is impossible to say whether or not the cost of cathodic protection of active ships is merited. Because corrosion damage to hulls seldom is considered except when perforations occur, or in destroyers and sub-marines where plates are thinner and original dimensions more critical, there is some belief that cathodic protection for all ships cannot be justified on a cost basis. With inactive ships, however, the reverse is true. Indefinite extension of drydocking times, the interval contingent on the exhaustion of anti-fouling paints, is anticipated. Initial cost of cathodic protection of active destroyers, submarines, and five types of reserve ships is tabulated. Details of cathodic protection systems for reserve ships are given. Criteria of protection differ somewhat from the accepted standards. In polluted waters inactive ships may require a potential in excess of 1 volt, while in other high resistivity waters 0.85 to 0.95 volts are sufficient. Some data are given on the cathodic protection of active ships. Merits of sacrificial anodes versus impressed current are listed. Extensive further activity in cathodically protecting active ships is contingent on the outcome of trials now under way.

Effect of Nano Zirconia on Microstructure and Electrochemical Behavior of Aluminium-Zinc Sacrificial Anodes

2012 ◽  
Vol 519 ◽  
pp. 41-44 ◽  
Author(s):  
Ying Zhang ◽  
Ai Chen ◽  
Cheng Liu ◽  
Hai Rong Wang ◽  
Ze Song Li
Keyword(s):  
Electrochemical Properties ◽  
Current Density ◽  
Electrochemical Behavior ◽  
Corrosion Current Density ◽  
Dendritic Structure ◽  
Corrosion Current ◽  
Sacrificial Anode ◽  
Sacrificial Anodes ◽  
Density Values

In this study, nano ZrO2 powders were incorporated into Al-5 wt% Zn sacrificial anode and the effect of ZrO2 contents (wt% =0.1, 0.2) on microstructures and electrochemical properties were investigated. The results show that the addition of nano ZrO2 was effective on improving metallurgical and electrochemical properties. With the increase of ZrO2 content, the dendritic structure is fined gradually and the corrosion current density values is also increased. The incorporation of ZrO2 also can result in a moderate efficiency value. When the ZrO2 content in the alloy was 0.2 wt%, the optimal microstructure, electrochemical properties and as high as 70% the efficiency value was obtained.

Study on the Electrochemical Behavior of Al-6Zn-0.02In-1Mg-0.03Ti Sacrificial Anodes for Long-Term Corrosion Protection in the Ocean

CORROSION ◽  
10.5006/3404 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 366-372 ◽  
Author(s):  
Mingkun Yang ◽  
Yan Liu ◽  
Zeyao Shi ◽  
Xiaodan Lv ◽  
Bin Liu ◽  
...  
Keyword(s):  
Mass Loss ◽  
Corrosion Product ◽  
Cathodic Protection ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Output Current ◽  
Alloy Anode ◽  
Sacrificial Anodes

After 10 y of service in the ocean, the long-term performance of Al-6Zn-0.02In-1Mg-0.03Ti aluminum alloy sacrificial anodes for steel piles was characterized by mass loss in addition to optical and electron microscopy analysis. The electrochemical behavior was conducted by open-circuit potential with potentiodynamic and potentiostatic polarizations. The results showed that cathodic protection potential was in the range of −0.960 VCSE to −1.103 VCSE. The corrosion type and consumption rate of the alloy anode were related to the output current. In harsh corrosion environments, the alloy anode showed uniform corrosion and lost more mass due to voltage output, therefore more current is needed to fulfill cathodic protection. Otherwise, localized corrosion and less mass loss were observed. The alloy anodes were covered by marine creatures and corrosion product. The corrosion product contained amorphous Al(OH)3 and MgAl2(CO3)(OH)·xH2O which became more crystalline from outside to inside of the alloy anode. A translucent corrosion product was found on the alloy anode surface which contained amorphous Al(OH)3·xH2O with S, along with AlxCly(OH)z·mH2O. The electrochemical performance of the alloy anode was strongly reduced by the coverage of corrosion product. Consequently, the open-circuit potential of the alloy anode increased and the output current decreased. The effect of corrosion product thicknesses on the anodic activation is not remarkable.

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.

Synthesis and Electrochemical Properties of Spherical LiFePO4/C Composite via Spray Drying

2015 ◽  
Vol 1120-1121 ◽  
pp. 554-558 ◽  
Author(s):  
Juan Mei Wang ◽  
Bing Ren ◽  
Ying Lin Yan ◽  
Qing Zhang ◽  
Yan Wang
Keyword(s):  
Diffusion Coefficient ◽  
Electrochemical Properties ◽  
Spray Drying ◽  
Electrochemical Impedance ◽  
Retention Rate ◽  
Lithium Ion ◽  
Constant Current ◽  
Ion Diffusion ◽  
Electrochemical Tests ◽  
Li Ion

In this work, spherical LiFePO4/C composite had been synthesized by co-precipitation and spray drying method. The structure, morphology and electrochemical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), transmission electron microscope (TEM), constant current charge-discharge tests and electrochemical impedance spectroscopy (EIS) tests. The spherical LiFePO4/C particles consisted of a number of smaller grains. The results showed that the morphology of LiFePO4/C particles seriously affected the Li-ion diffusion coefficient and electrochemical properties of lithium ion batteries. Electrochemical tests revealed the spherical LiFePO4/C composite had excellent Li-ion diffusion coefficient which was calculated to be 1.065×10-11 cm2/s and discharge capacity of 149 (0.1 C), 139 (0.2 C), 133 (0.5 C), 129 (1 C) and 124 mAhg-1(2 C). After 50 cycles, the capacity retention rate was still 93.5%.

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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