scholarly journals Erosion Corrosion Behavior of Aluminum in Flowing Deionized Water at Various Temperatures

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 779
Author(s):  
Liangshou Hao ◽  
Feng Zheng ◽  
Xiaoping Chen ◽  
Jiayang Li ◽  
Shengping Wang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Water Temperature ◽  
Corrosion Current ◽  
Deionized Water ◽  
Aluminum Surface ◽  
Aluminum Electrode ◽  
Transfer Impedance ◽  
Corrosion Reaction ◽  
Erosion Corrosion ◽  
Aluminum Corrosion

To optimize the operating temperature and flow velocity of cooling water in a high voltage direct current (HVDC) thyristor valve cooling system, the erosion corrosion characteristics of aluminum electrodes in deionized water at various temperatures were studied. With increasing water temperature, the corrosion current of the aluminum electrode gradually increases and the charge transfer impedance gradually decreases, thus, the corrosion of aluminum tends to become serious. The aluminum electrode in 50 °C deionized water has the most negative corrosion potential (−0.930 V), the maximum corrosion current (1.115 × 10−6 A cm−2) and the minimum charge transfer impedance (8.828 × 10−6 Ω), thus, the aluminum corrosion at this temperature is the most serious. When the temperature of deionized water increases, the thermodynamic activity of the ions and dissolved oxygen in the deionized water increases, and the mass transfer process accelerates. Therefore, the electrochemical corrosion reaction of the aluminum surface will be accelerated. The corrosion products covering the aluminum electrode surface are mainly Al(OH)3. With increasing water temperature, the number of pits and grooves formed by corrosion on the aluminum surface increased. In this paper, the molar activation energy Ea and the equilibrium constant K of the aluminum corrosion reaction with various temperatures are calculated. This clarifies the effect of temperature on the aluminum corrosion reaction, which provides a basis for protecting aluminum from corrosion. The results of this study will contribute to research that is focused on the improvement of production techniques used for HVDC thyristor valve cooling systems.

scholarly journals Electrochemical, Thermodynamic, Surface, and Spectroscopic Study in Inhibition of Iron Corrosion with Turmeric Root Extract (TRE)

2020 ◽  
Author(s):  
Khuloud Almzarzie ◽  
Ayman Almassri ◽  
Ahmad Falah ◽  
Hassan Kellawi
Keyword(s):  
Charge Transfer ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Root Extract ◽  
Iron Corrosion ◽  
Transfer Resistance ◽  
Corrosion Reaction ◽  
Capacitive Loop

Turmeric root extract was tested as corrosion inhibitor for iron in 0.5 M HCl, using potentiodynamic polarization and electrochemical impedance spectroscopy, scanning electron microscope, and energy dispersive X-ray analysis. The inhibition efficiency increases as the time of immersion rises but decreases with temperature rise. The Nyquist plots showed that the charge transfer resistance increases and the double-layer capacitance decreases as the time of immersion increases. Tafel results show that both corrosion current and corrosion speed are reduced with time of immersion. All impedance spectra of EIS tests exhibit one capacitive loop, which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiency increases with the concentration of the inhibitor reaching its maximum value, 88.90%, at 8 g/100 mL. Thermodynamic parameters, Ea, ∆H*, and ∆S*, were estimated, and the mechanism of corrosion and inhibition was discussed. The adsorption of turmeric root extract followed Langmuir adsorption isotherm.

Porous diatomite-mixed 1,4,5,8-NTCDA nanowires as high-performance electrode materials for lithium-ion batteries

Nanoscale ◽  
2019 ◽  
Vol 11 (34) ◽  
pp. 15881-15891 ◽  
Author(s):  
Yong Xu ◽  
Jun Chen ◽  
Ze'en Xiao ◽  
Caixia Ou ◽  
Weixia Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Lithium Ion Batteries ◽  
High Performance ◽  
Composite Electrode ◽  
Electrode Materials ◽  
Lithium Ion ◽  
Rate Performance ◽  
Transfer Impedance ◽  
Lower Charge

A novel porous diatomite composite electrode composed of NTCDA nanowires exhibits lower charge transfer impedance, higher capacity and better rate performance.

Adsorption mechanism of CO molecule on Al(111) surface: periodic DFT investigation

2018 ◽  
Vol 96 (12) ◽  
pp. 993-999 ◽  
Author(s):  
Chenhong Xu ◽  
Suqin Zhou ◽  
Jing Chen ◽  
Yuxiang Wang ◽  
Lei He
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Adsorption Mechanism ◽  
Bond Activation ◽  
Aluminum Surface ◽  
Hollow Site ◽  
Functional Theory ◽  
Wide Range ◽  
Adsorption Of Co ◽  
Adsorption Energies

The adsorption mechanism of the CO molecule on Al(111) surface has been investigated systematically at the atom-molecule level by the method of periodic density functional theory. The adsorption energies, adsorption structures, charge transfer, and density of states have been calculated in a wide range of coverage. It is found that the hcp-hollow site is the energetically favorable site. A significant positive correlation has been found between the adsorption energy (Eads) and coverage. The adsorbed CO molecules are almost perpendicular on the surface with the C atom facing the surface. There is an obvious charge transfer from Al atoms to the C atom; the Al atoms that have interaction with the C atom offer the most charge. The 4σ, 1π, and 5σ molecular orbitals of CO are found to contribute to bonding with the Al. The charges filling in the 2π molecular orbital contribute to C–O bond activation. In conclusion, the passivation of aluminum surface and the activation of CO molecule occur simultaneously in the adsorption of CO on Al surface.

scholarly journals Wettability and Anti-Corrosion Performances of Carbon Nanotube-Silane Composite Coatings

Fibers ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 57
Author(s):  
Luigi Calabrese ◽  
Amani Khaskoussi ◽  
Edoardo Proverbio
Keyword(s):  
Aluminum Alloy ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Sol Gel ◽  
Corrosion Current ◽  
Nanocomposite Coating ◽  
Multi Wall Carbon Nanotubes ◽  
Aluminum Corrosion ◽  
Order Of Magnitude ◽  
The Stability

In this paper, a sol-gel N-propyl-trimethoxy-silane coating filled with different amount of multi-wall carbon nanotubes (MWCNTs) was investigated in order to improve the aluminum corrosion resistance. The nanocomposite coating was applied, by drop casting, on AA6061 aluminum alloy substrate. The morphological analysis highlighted that a uniform sol-gel coating was obtained with 0.4 wt.% CNT. Lower or higher nanotube contents lead to the formation of heterogeneities or agglomeration in the coating, respectively. Furthermore, all nanocomposite coatings exhibited effective adhesion to the substrate. In particular, the pull-off strength ranged in 0.82–1.17 MPa. Corrosion protection of the aluminum alloy in NaCl 3.5 wt.% electrolyte (seawater) was significantly improved after CNT addition to the base coating. The stability in electrochemical impedance was observed during three days of immersion in the sodium chloride solution. AS3-CNT2 and AS3-CNT4 batches showed advanced electrochemical stability during immersion tests. Furthermore, interesting results were evidenced in potentiodynamic polarization curves where a decrease of the corrosion current of at least two order of magnitude was observed. Moreover, the breakdown potential was shifted toward noble values. Best results were observed on AS3-CNT6 specimen which exhibited a passivation current density of approximately 1.0 × 10−5 mA/cm2 and a breaking potential of 0.620 V/AgAgClsat.

scholarly journals The Design of ACE (Aluminum Corrosion and Electrolysis) Reactor and Its Performance to Produce Hydrogen from Beverage Cans

REAKTOR ◽  
2018 ◽  
Vol 17 (4) ◽  
pp. 210 ◽  
Author(s):  
Ahmad Zikri ◽  
Erlinawati . ◽  
Lety Trisnaliani ◽  
Daya Wulandari
Keyword(s):  
Potassium Hydroxide Solution ◽  
Oxide Coating ◽  
Water Electrolysis ◽  
Hydrogen Gas ◽  
Hydrogen Water ◽  
Corrosion Reaction ◽  
Production Of Hydrogen ◽  
Aluminum Corrosion ◽  
Long Time ◽  
Maximum Production Rate

AbstractThe reaction of aluminum (Al) with an alkaline solution in producing hydrogen gas has been known for a long time. This aluminum corrosion reaction has a major obstacle in the passivation phenomenon, a formation of aluminum oxide coating on the metal surface that prevents aluminum from collapsing. Integration of electric current to the potassium hydroxide solution could result in electrolysis of water which increases the production of hydrogen. This process was carried out continuously in an ACE (aluminum corrosion and electrolysis) reactor of water. This reactor design enabled to produce hydrogen and oxygen in separating chamber. The use of 10 g of cans, 0.02 M gallium, 12 VDC, and 0.8 M KOH obtained the maximum production rate of hydrogen 162.58 ml/s with a purity of 79.83%. Keywords: aluminum corrosion; hydrogen; water electrolysis

scholarly journals Aluminum corrosion inhibition by cefixime drug: experimental and DFT studies

2018 ◽  
Vol 8 (4) ◽  
pp. 303-320 ◽  
Author(s):  
N’guessan Yao Silvere Diki ◽  
Gildas K. Gbassi ◽  
Augustin Ouedraogo ◽  
Mohamed Berte ◽  
Albert Trokourey
Keyword(s):  
Mass Loss ◽  
Corrosion Inhibition ◽  
Density Functional ◽  
Solution Temperature ◽  
Aluminum Surface ◽  
Protective Film ◽  
Tafel Polarization ◽  
Quantum Chemical Methods ◽  
Aluminum Corrosion ◽  
Global And Local

Corrosion inhibition of aluminum in 1 M HCl by cefixime drug has been studied at 298-318 K using mass loss, Tafel polarization (at 298 K) and quantum chemical methods based on density functional theory (DFT) calculations. The results showed that inhibition efficiency increases up to 90.41 % with increase of the inhibitor concentration from 0.02 to 2 mM, but decreases with a rise of the solution temperature. Adsorption of cefixime molecules on the corroding aluminum surface obeys Langmuir adsorption isotherm and occurs spontaneously mostly through a physisorption process. The activation energy (Ea) as well as other thermodynamic parameters of the inhibition process are calculated and discussed. Potentiodynamic polarization data revealed that cefixime acts as mixed-type inhibitor and pointed out an agreement with mass loss results. Surface analysis is performed using scanning electron microscopy (SEM) which confirmed existence of a protective film of inhibitor molecules on the aluminum surface. In addition, global and local reactivity parameters of the studied molecule are analyzed and discussed. The computed results are found in agreement with experimental data.

scholarly journals Effect of Nickel-Coated Precipitated Calcium Carbonate on Corrosion Properties of Sn-9Zn Solder

2021 ◽  
Vol 2080 (1) ◽  
pp. 012019
Author(s):  
Wai Keong Leong ◽  
Ahmad Azmin Mohamad ◽  
Muhammad Firdaus Mohd Nazeri
Keyword(s):  
Calcium Carbonate ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Corrosion Performance ◽  
Precipitated Calcium Carbonate ◽  
Corrosion Properties ◽  
Corrosion Reaction ◽  
Before And After ◽  
Morphological Differences ◽  
Kinetics Of

Abstract The effect of 0.5 wt. % Nickel (Ni)-coated precipitated calcium carbonate (PCC) additions on the corrosion properties of Sn-9Zn solder was investigated in 3.5% sodium chloride (NaCl) solution employing potentiodynamic polarization. The morphological differences before and after corrosion analysis have been investigated to support the findings. The scan rate used was 1 mVs−1 after stable potential developed. Slight improvement of corrosion potential (Ecorr) with a significant reduction in corrosion current (icorr) was seen for the Sn-9Zn/Ni-coated PCC compared to Sn-9Zn, indicating the kinetics of corrosion reaction was reduced. The current consumed under the passivation stage for the Sn-9Zn/Ni-coated PCC was also smaller, highlighting that further corrosion protection was improved. Microstructural observation also verified that the number and size of blackish spot clusters were reduced for the Sn-9Zn/Ni-coated PCC, revealing that Ni-PCC additions improve the overall corrosion performance of Sn-9Zn solder.

scholarly journals Surface degradation of Li1–xNi0.80Co0.15Al0.05O2 cathodes: Correlating charge transfer impedance with surface phase transformations

2016 ◽  
Vol 108 (26) ◽  
pp. 263902 ◽  
Author(s):  
S. Sallis ◽  
N. Pereira ◽  
P. Mukherjee ◽  
N. F. Quackenbush ◽  
N. Faenza ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Phase Transformations ◽  
Surface Phase ◽  
Surface Degradation ◽  
Transfer Impedance
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