scholarly journals Inhibition of Copper Corrosion by Rice Straw Extract in 2M Solution of Nitric Acid

2021 ◽  
Vol 12 (1) ◽  
pp. 83-104
Keyword(s):  
Rice Straw ◽  
Charge Transfer Resistance ◽  
Adsorption Parameters ◽  
Green Inhibitor ◽  
Transfer Resistance ◽  
Electrochemical Tests ◽  
Langmuir Adsorption ◽  
Different Temperatures ◽  
Protection Efficacy ◽  
Cu Dissolution

In our research, the rice straw extract was utilized as an eco-friendly green inhibitor to prevent Cu dissolution in 2 M of HNO3. Mass loss, electrochemical tests, and surface checks were utilized to demonstrate the importance of this green extract to prevent the Cu corrosion procedure. From all tests, one can find that with increasing the dose of rice straw extract (up to 300 ppm), the protection efficacy increased to 96.8% at 25°C. Polarization curves showed that rice straw extract is a mixed-kind inhibitor that retards the anodic and cathodic reactions. From the EIS examination, the double-layer capacitance lowered by improving the dose of rice straw extract was noticed. On the other hand, the charge transfer resistance was improved. The corrosion protection (% I) of Cu occurs by the adsorption procedure, and this metal is followed by the Flory-Huggins and Langmuir adsorption isotherms. From both isotherms, the adsorption parameters were deduced. This test was also applied at different temperatures, and the activated parameters were determined and discussed. Results gotten from all used tests are in excellent harmony.

scholarly journals Recycling of Expired Ceftamil Drug as Additive in the Copper and Nickel Electrodeposition from Acid Baths

2021 ◽  
Vol 18 (18) ◽  
pp. 9476
Author(s):  
Delia-Andrada Duca ◽  
Mircea Laurențiu Dan ◽  
Nicolae Vaszilcsin
Keyword(s):  
Organic Molecules ◽  
Electrochemical Impedance ◽  
Electrolyte Solutions ◽  
Optical Microscope ◽  
Charge Transfer Resistance ◽  
Favorable Effect ◽  
Transfer Resistance ◽  
Nickel Electrodeposition ◽  
Nickel Electroplating ◽  
Different Temperatures

Due to the large quantity of expired and unused drugs worldwide, pharmaceutical disposal has become a serious problem that requires increased attention. In the present paper, the study on recycling ceftazidime (CZ) as an additive in copper and nickel electrodeposition from acid baths is highlighted. CZ is the active substance from expired commercial drug Ceftamil®. Its electrochemical behavior was studied by cyclic voltammetry. As well, kinetic parameters for copper and nickel electrodeposition were determined using Tafel plots method at different temperatures and CZ concentrations in these acid baths. The activation energy was calculated from Arrhenius plots. Electrochemical impedance spectroscopy was used to investigate the charge transfer resistance and coverage degree in the electrolyte solutions at several potential values. Gibbs free energy values, calculated from Langmuir adsorption isotherms, revealed the chemical nature of CZ–electrode surface interactions. The favorable effect of the organic molecules added in copper and nickel electroplating baths was emphasized by optical microscope images. The morphology of the obtained deposits without and with 10−4 mol L−1 CZ was compared. The experimental results revealed that expired Ceftamil® is suitable as additive in copper and nickel electroplating processes from acid baths.

scholarly journals Photoelectrochemical Performance of Smooth TiO2Nanotube Arrays: Effect of Anodization Temperature and Cleaning Methods

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Chin Wei Lai ◽  
Srimala Sreekantan
Keyword(s):  
Wall Thickness ◽  
High Efficiency ◽  
Charge Transfer Resistance ◽  
Nanotube Arrays ◽  
Photoelectrochemical Performance ◽  
Transfer Resistance ◽  
Self Organized ◽  
Different Temperatures ◽  
Cleaning Methods ◽  
Low Charge

The formation of self-organized titanium dioxide (TiO2) nanotube arrays without bundling or clustering is essential for their high efficiency in photoelectrochemical (PEC) application. The present paper reports on the use of different temperatures to control the specific architecture of nanotube arrays and effective cleaning techniques to ensure the formation of clean TiO2nanotube surface. The wall thickness of nanotube arrays could be controlled from 12.5 nm to 37.5 nm through different anodization temperature ranging from 10°C to 80°C. Furthermore, ultrasonic cleaning combined with acetone showed the high-ordered TiO2nanotube arrays without morphological disorder, bundling, and microcrack problems. Based on the results obtained, a higher PEC response of 1 mA/cm2and a photoconversion efficiency of 1.3% could be achieved using a wall thickness of 12.5 nm and defect-free TiO2nanotube arrays for low charge transfer resistance.

scholarly journals Synthesis of MoIn2S4@CNTs Composite Counter Electrode for Dye-Sensitized Solar Cells

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Gentian Yue ◽  
Renzhi Cheng ◽  
Xueman Gao ◽  
Leqing Fan ◽  
Yangfan Mao ◽  
...  
Keyword(s):  
Counter Electrode ◽  
Electrochemical Impedance ◽  
Dye Sensitized Solar Cells ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Electrochemical Tests ◽  
One Step ◽  
Low Charge ◽  
Adsorption Desorption ◽  
Sensitized Solar Cells

Abstract A ternary and composite MoIn2S4@CNTs counter electrode (CE) with a hedgehog ball structure was synthesized by using a facile one-step hydrothermal method. The composite MoIn2S4@CNTs film possesses large specific surface area through N2 adsorption-desorption isotherms test, which is advantageous to adsorb more electrolyte and provide larger active contact area for the electrode. In addition, the composite MoIn2S4@CNTs CE exhibits low charge transfer resistance and fine electrocatalytic ability made from a series of electrochemical tests including cyclic voltammetry, electrochemical impedance, and Tafel curves. Under optimal conditions, the DSSC based on the MoIn2S4@CNTs-2 composite CE achieves an impressive power conversion efficiency as high as 8.38%, which remarkably exceeds that of the DSSCs with the MoIn2S4 CE (7.44%) and the Pt electrode (8.01%). The current work provides a simplified preparation process for the DSSCs.

scholarly journals Corrosion Behavior of Alloyed Cast Iron in Ethylene Glycol-Based Engine Coolants at Elevated Temperature

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 357
Author(s):  
Gaurav Argade ◽  
Anusha Chilukuri ◽  
Justin Perry ◽  
Monica Viers ◽  
Jacob Steenhoek ◽  
...  
Keyword(s):  
Cast Iron ◽  
Elevated Temperature ◽  
Electrochemical Impedance ◽  
Engine Performance ◽  
Sharp Decrease ◽  
Charge Transfer Resistance ◽  
Organic Additives ◽  
Transfer Resistance ◽  
Electrochemical Tests ◽  
Engine Coolant

For enhanced engine performance, corrosivity of the engine coolants would play a significant role. In this work, corrosion investigation was performed on cast iron material in pre-mixed engine coolant environment to understand the threshold limits of contaminants. The pre-mixed coolant contained combination of organic additives viz. sebacate (SA), 2-ethylhexonate (2-EH), and tolyltriazole (TTA) with varying concentrations of chloride contaminant. Constant immersion of cast iron samples in engine coolant with different chloride levels at 90 °C was followed by room temperature electrochemical tests. The potentiodynamic polarization tests showed no instability until 100 ppm chloride additions exposed up to 28 days. At lower frequencies in electrochemical impedance spectroscopy (EIS) spectra, inhibition layer characteristics changed from highly capacitive to highly resistive and concurrently a sharp decrease in charge transfer resistance was observed with time for samples exposed to >100 ppm chloride levels. In the longer duration corrosion tests, higher pit depths with increased number density of attacks were observed for cast iron samples exposed to engine coolants containing >100 ppm chloride. For elevated temperature exposures a threshold limit of <200 ppm chloride was established for cast iron samples.

The influence of membrane electrode assembly’s pressing on PEM fuel cell’s performance

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Federico Perdomo ◽  
Matilde Abboud ◽  
Erika Teliz ◽  
Fernando Zinola ◽  
Verónica Díaz
Keyword(s):  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Membrane Electrode Assembly ◽  
Charge Transfer Resistance ◽  
Open Circuit ◽  
Polymeric Membrane ◽  
Membrane Electrode ◽  
Transfer Resistance ◽  
Supported Platinum Catalysts ◽  
Different Temperatures

Abstract The performance of a fuel cell depends on multiple factors, one of the most important being the preparation of the membrane electrode assembly (MEA). In the present work, MEAs constituted by gas diffuser electrodes (GDE) were pressed with carbon supported platinum catalysts. As solid electrolyte, a commercial polymeric membrane from Nafion was used, which was pressed at two GDE with loads of 5 and 1.5 mg/cm2 of catalyst at different temperatures and pressures for a fixed period of time. The assembly was characterized electrochemically using linear sweep voltammetry and electrochemical impedance spectroscopy at three different potentials. Also, the behavior when reversing the supply of hydrogen and oxygen to the GDE was studied. The results of the study showed a great dependence of the charge transfer resistance with the temperature, being secondary the dependence with the pressure in the range of temperature and pressure analyzed. Likewise, changes were observed in the open circuit potential after varying the temperature, pressure and catalyst load, hence affecting its maximum power and efficiency at that point.

scholarly journals Corrosion inhibition of iron in chloride media by the aqueous extract of Curcuma longa rhizome powder

2021 ◽  
Vol 48 (2) ◽  
Author(s):  
Imen AbidlI ◽  
◽  
Nébil Souissi ◽  
X. Ramón Novoa ◽  
◽  
...  
Keyword(s):  
Aqueous Extract ◽  
Electrochemical Impedance ◽  
Curcuma Longa ◽  
Charge Transfer Resistance ◽  
Langmuir Adsorption Isotherm ◽  
Nacl Solution ◽  
Iron Corrosion ◽  
Transfer Resistance ◽  
Time Effects ◽  
Langmuir Adsorption

The effect of the aqueous extract of Curcuma Longa Rhizome Powder and their main constituents involve phenolic compounds, as an iron corrosion inhibitor in 0.1 M NaCl solution was tested. Electrochemical impedance spectroscopy (EIS) was employed as the main experimental technique to assess the electrochemical behavior of iron in different concentrations of Curcuma extract. EIS revealed an increase of the charge transfer resistance with increasing inhibitor concentration. The temperature and immersion time effects on the corrosion behavior of iron without and with the extract of Curcuma were also studied. The inhibition action of the extract was discussed in view of the Langmuir adsorption isotherm.

scholarly journals MORPHOLOGICAL, STRUCTURAL, MICROHARDNESS AND ELECTROCHEMICAL CHARACTERIZATIONS OF ELECTRODEPOSITED Cr AND Ni–W COATINGS

2018 ◽  
Vol 24 (3) ◽  
pp. 234 ◽  
Author(s):  
Elkhanssa Aidaoui ◽  
Hachemi Ben Temam ◽  
Okba Belahssen ◽  
El Hachmi Guettaf Temam
Keyword(s):  
Current Density ◽  
Electrochemical Impedance ◽  
Electrochemical Characterizations ◽  
Copper Substrate ◽  
Charge Transfer Resistance ◽  
Applied Current ◽  
Transfer Resistance ◽  
Electrochemical Tests ◽  
Cu Substrates ◽  
Xrd Patterns

<p class="AMSmaintext">Currently, Ni-Cr coatings are widely used in a number of important applications due to their excellent properties. In this study, Ni-Cr alloys were electrodeposited from citrate bath onto Cu substrates by using different values of applied current densities. The effects of plating deposition current density on morphological and structural characterization of Ni-Cr electrodeposited coatings were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). Microhardness of the coatings is also evaluated using Vickers’s microhardness. Potentio-dynamic polarization and electrochemical impedance spectroscopy (EIS) tests in 3.5wt % NaCl solution were used to evaluate corrosion résistance of Ni-Cr coatings. The results showed that the surface morphology of the all coatings contained micro cracks and pores. XRD patterns indicate the formation of Ni-Cr and Cr<sub>3</sub>Ni<sub>2</sub> phases. Microhardness measurements show that all Ni-Cr samples are hardener than copper substrate. Electrochemical tests show that 3 A/dm² is an optimal value of applied current density in the sense of the least value of E<sub>corr</sub> and the best charge transfer resistance R<sub>p</sub>.</p>

Corrosion Behavior of Zinc Covered with Native Oxides Under Thin Solution Films

CORROSION ◽  
10.5006/3523 ◽  
2020 ◽  
Vol 76 (6) ◽  
pp. 562-569
Author(s):  
Chulaluk Somphotch ◽  
Azusa Ooi ◽  
Eiji Tada ◽  
Atsushi Nishikata
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Native Oxide ◽  
Transfer Resistance ◽  
Native Oxides ◽  
Different Temperatures ◽  
Humidified Air

This study clarified the influence of native oxides on the atmospheric corrosion of Zn. The electrochemical impedance spectroscopy (EIS) values of native-oxide-covered Zn were measured under thin solution films of 10 μm to 500 μm in thickness. The native oxides were formed by exposing pure Zn plates to humidified air at two different temperatures, 25°C and 60°C, for the duration of one week. EIS was applied to the native-oxide-covered Zn for measurement under thin solution films; the results were analyzed using a transmission line equivalent circuit to determine the charge-transfer resistance (Rct). The native oxide formed at 25°C strongly suppressed the corrosion rate (1/Rct) of Zn, which was independent of the solution film thickness (Xf). However, the 1/Rct was not reduced by the native oxides formed at 60°C, as it was dependent on Xf. This paper discusses the different behaviors of the native oxides in the context of corrosion protection.

IMMERSION AND ELECTROCHEMICAL TESTS STUDY ON CORROSION RESISTANCE OF CHROME-FREE CHEMICAL CONVERSION FILM ON AZ91D Mg ALLOY IN 5 wt% NaCl SOLUTION

2005 ◽  
Vol 12 (03) ◽  
pp. 417-424
Author(s):  
X. P. ZHANG ◽  
G. CHEN
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Chemical Conversion ◽  
Alloy Coating ◽  
Charge Transfer Resistance ◽  
Mg Alloy ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Electrochemical Tests

Immersion and electrochemical tests have been applied to study corrosion protection of AZ91D Mg alloy coating with chrome-free chemical conversion (CCC) coat in 5wt% NaCl solution. The immersions tests include weight-loss measurements after full or partial immersion with whole coating and full immersion with damaged coating. The electrochemical tests include electrochemical impedance spectroscopy (EIS) and polarization curves measurement. The results of immersion and electrochemical tests show that chrome-free chemical conversion (CCC) surface treatment can significantly improve the corrosion resistance of AZ91D Mg alloy in 5% NaCl solution, and that the corrosion protection effect of CCC coating is not sensitive to pores or cracks. The equivalent circuit models are fitted from Nyquist plots for the uncoated specimens and the CCC-coated specimens. The charge transfer resistance, R ct , increases from about 1.669 Ω cm2 for the uncoated alloy to about 210 Ω cm2 after the alloy is coated with CCC coating.

scholarly journals Electrochemical behavior for corrosion protection of mild steel (MS) in 1M HCl medium by using lidocaine drug as an inhibitor

2020 ◽  
Vol 61 (4) ◽  
pp. 286-305
Author(s):  
Ali Adel ◽  
El-Aziz Abd ◽  
Tilp Amal
Keyword(s):  
Weight Loss ◽  
Mild Steel ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Adsorption Parameters ◽  
Transfer Resistance ◽  
Surface Examination ◽  
The Impact

The impact of Lidocaine as a save corrosion inhibitor for mild steel (MS) in 1M HCl by using weight loss (WL), Hydrogen evaluation (HE), open circuit potential (EO C P), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and Electrochemical frequency modulation (EFM) techniques has been investigated. Weight loss studied at various temperatures between (25-45oC) but Hydrogen evaluation and electrochemical studies at room temperature. The effect of temperature on the inhibition of corrosion has been studied and the thermodynamic activation and adsorption parameters were calculated. The morphology of MS was examined by scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX) technology and atomic force microscopy (AFM). EIS data indicate that in the presence of drug the double layer capacitance was decreased and the charge transfer resistance increased. The adsorption of the Lidocaine on MS surface was found to obey Langmuir adsorption isotherm and elucidate the mechanism of corrosion inhibition. The Lidocaine drug acts as mixed type inhibitor. All surface examination confirms the formation thin film covered the surface of the metal and prevent the surface of the metal from corrosion.

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