scholarly journals The Video Microscopy-Linked Electrochemical Cell: An Innovative Method to Improve Electrochemical Investigations of Biodegradable Metals

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1601
Author(s):  
Tycho Zimmermann ◽  
Norbert Hort ◽  
Yuqiuhan Zhang ◽  
Wolf-Dieter Müller ◽  
Andreas Schwitalla
Keyword(s):  
Electrochemical Cell ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Cell System ◽  
Open Circuit ◽  
Dynamic Conditions ◽  
Electrochemical Tests ◽  
Oxide Deposition ◽  
Set Up ◽  
Voltammetry Methods

An innovative, miniature video-optical-electrochemical cell was developed and tested that allows for the conducting of electrochemical corrosion measurements and simultaneous microscopic observations over a small, well-defined surface area of corroding or degrading samples. The setup consisted of a miniature electrochemical cell that was clamped onto the metal sample and fixed under a video microscope before being filled with electrolyte. The miniature cell was comprised of afferent/efferent electrolyte ducts as well as a connection to the Mini Cell System (MCS) for electrochemical measurements. Consequently, all measured and induced currents and voltages referred to the same small area corroding completely within the field of view of the microscope, thus allowing for real-time observation and linking of surface phenomena such as hydrogen evolution and oxide deposition to electrochemical data. The experimental setup was tested on commercial purity (cp) and extra-high purity (XHP) magnesium (Mg) samples using open circuit potential and cyclic voltammetry methods under static and flowing conditions. The corrosion potential was shifted more anodically for cp Mg in comparison to XHP Mg under dynamic conditions. The corrosion current assessed from the cyclic voltametric curves were higher for the cp Mg in comparison to XHP Mg. However, there were no differences between static and flow conditions in the case of XHP Mg in contrast to cp Mg, where the current density was two times higher at dynamic conditions. The measurements and observations with this new method pave the way for a more detailed understanding of magnesium corrosion mechanisms, thus improving predictive power of electrochemical corrosion measurements on newly developed magnesium or other biodegradable alloys applied for medical devices. Different electrochemical tests can be run under various conditions, while being easy to set up and reproduce as well as being minimally destructive to the sample.

Structure and Resistance to Electrochemical Corrosion of NiTi Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 335-338 ◽  
Author(s):  
Bożena Łosiewicz ◽  
Magdalena Popczyk ◽  
Tomasz Goryczka ◽  
Józef Lelątko ◽  
Agnieszka Smołka ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Niti Alloy ◽  
Electrochemical Corrosion ◽  
High Resolution Electron Microscopy ◽  
Potential Method ◽  
Passive Layer ◽  
Open Circuit ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Reflectivity Method

The NiTi alloy (50.6 at.% Ni) passivated for 30 min at 130°C by autoclaving has been studied towards corrosion resistance in aqueous solutions of 3% NaCl, 0.1 M H2SO4, 1 M H2SO4 and HBSS. Structure and thickness of the passive layer (TiO2, rutile) were examined by X-ray reflectivity method and high resolution electron microscopy. Corrosion behavior of this oxide layer was investigated by open circuit potential method and polarization curves. It was found that the corrosion resistance of the passivated NiTi alloy is strongly dependent on the type of corrosive environment. The higher corrosion resistance of the tested samples was revealed in sulfate solutions as compared to chloride ones. The highest resistance to electrochemical corrosion of the NiTi alloy was observed in 0.1 M H2SO4 solution. Susceptibility to pitting corrosion of the tested samples was observed which increased with the concentration rise of chlorine anions in solution. Electrochemical tests for 316L stainless steel carried out under the same experimental conditions revealed a weaker corrosion resistance in all solutions as compared to the highly corrosion resistant NiTi alloy.

scholarly journals Corrosion investigations of Al-Si casting alloys in 0.6 M NaCl solution

2021 ◽  
Vol 41 (3) ◽  
Author(s):  
Sunčana Smokvina Hanza ◽  
Ladislav Vrsalović ◽  
Lovro Štic ◽  
Lovro Liverić
Keyword(s):  
Potentiodynamic Polarization ◽  
Electrochemical Behavior ◽  
Die Casting ◽  
Electrochemical Corrosion ◽  
Microstructural Characterization ◽  
Casting Process ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Open Circuit ◽  
Polarization Measurements

This paper presents results of the corrosion investigations of specimens made from finished parts for the automotive industry, produced by high-pressure die casting and gravity die casting process of six Al-Si alloys (40000 series). Open circuit potential and potentiodynamic polarization measurements have been performed using a potentiostat with three-electrode set-up in 0.6 M NaCl naturally aerated solution. Microstructural characterization before and after electrochemical investigations has been carried out with optical microscope to establish the connection between microstructure and corrosion parameters of investigated alloys and to analyze and record surface changes of each sample due to electrochemical corrosion. All alloys show good corrosion resistance, which manifests with low values of corrosion rates, calculated from the corrosion current densities obtained from potentiodynamic polarization measurements. Differences in electrochemical behavior appear due to the distinctions in their chemical composition and microstructure. The type of casting process does not affect electrochemical behavior of Al-Si alloys.

Electrochemical Corrosion Behaviour of ZrN Film in Various Corrosive Fluid

2015 ◽  
Vol 3 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Vishnu R. ◽  
Jiten Das ◽  
S. B. Arya ◽  
Manish Roy
Keyword(s):  
Sea Water ◽  
Corrosion Behaviour ◽  
Water Solution ◽  
Electrochemical Corrosion ◽  
High Hardness ◽  
Corrosion Current ◽  
Plain Carbon Steel ◽  
Open Circuit ◽  
Protective Film ◽  
Hank’S Solution

Recently, ZrN has been attracting interest for its excellent corrosion resistance, biocompatibility, high hardness, good lubricity and ductility. Although tribological study of ZrN coating has been carried out extensively, investigation related to corrosion of ZrN film is limited. In view of this and in view of possible applications of ZrN film in several engineering components, the present investigation has been undertaken to evaluate the corrosion response of ZrN film in seawater solution, Hank's solution, 0.5M H2SO4solution and 0.5M HCl solutions. Towards that purpose, potentiostatic, open circuit potential and potentiodynamic study of ZrN film deposited on plain carbon steel has been carried out in all these solutions. Results indicate that stable protective film is formed on the surface of ZrN coating in all these solution except 0.5M H2SO4 solution. The formation of protective film on ZrN coating is fastest in sea water solution and it is slowest in the Cl¯ ions containing media, 0.5 M HCl. The corrosion current is highest for 0.5M H2SO4 acid solution and least for Hank's solution.

Effect of High-Intensity Pulsed Ion Beam Irradiation on the Electrochemical Corrosion Behavior of AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 571-574
Author(s):  
Peng Li
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Current Density ◽  
Ion Beam ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Electrochemical Corrosion Behavior ◽  
Shot Number

HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.

Effect of mechanical stress on electrochemical corrosion of X65 carbon steel in CO2 saturated brine

2020 ◽  
Vol 62 (8) ◽  
pp. 803-808
Author(s):  
Wei Yan
Keyword(s):  
Mechanical Stress ◽  
Applied Stress ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Experimental Tests ◽  
Corrosion Current ◽  
Weak Acid ◽  
Open Circuit ◽  
Electrochemical Process ◽  
Metal Corrosion

Abstract Applied mechanical stress could accelerate the chemical or electrochemical process of metal corrosion in weak acid solution. Series of experimental tests were conducted in this research. The results show that there is no obvious correlation between OCP (open circuit potential) values and applied stresses. However, The LPR (linear polarization resistance)corrosion rate increased intensively under the applied stress of 400 MPa. Correspondingly, the EIS (electrochemical impedance spectroscopy) Nyquist diagrams show that all of the plots contain a semicircle over the whole frequency range and the semicircle size decreased with increasing applied stress. The real-time corrosion current square waves triggered by the mechanical stress were successfully monitored by using the potentiostatic method in CO2 saturated brine under 200 mv (above OCP), flow and lower pH condition. This result is significant for many research fields, such as petrochemistry, aerospace and nuclear industries, which suffer weak acid corrosive environment.

scholarly journals The Effect of Immersion Corrosion Time on Electrochemical Corrosion Behavior and the Corrosion Mechanism of EH47 Ship Steel in Seawater

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1317
Author(s):  
Hongmei Zhang ◽  
Ling Yan ◽  
Yangyang Zhu ◽  
Fangfang Ai ◽  
Hongnan Li ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Open Circuit ◽  
Corrosion Mechanism ◽  
Immersion Corrosion ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Time

In this paper, electrochemical corrosion tests and full immersion corrosion experiments were conducted in seawater at room temperature to investigate the electrochemical corrosion behavior and the corrosion mechanism of high-strength EH47. The polarization curve, EIS (electrochemical impedance spectroscopy), SEM (scanning electron microscope), and EDS analyses were employed to analyze the results of the electrochemical corrosion process. The electrochemical corrosion experiments showed that the open circuit potential of EH47 decreases and then increases with an increase in total immersion time, with the minimum value obtained at 28 days. With an increase in immersion time, the corrosion current density (Icorr) of EH47 steel first decreases and then increases, with the minimum at about 28 days. This 28-day sample also showed the maximum capacitance arc radius, the maximum impedance and the minimum corrosion rate. In the seawater immersion test in the laboratory, the corrosion mechanism of EH47 steel in the initial stage of corrosion is mainly pitting corrosion, accompanied by a small amount of crevice corrosion with increased corrosion time. The corrosion products of EH47 steel after immersion in seawater for 30 days are mainly composed of FeOOH, Fe3O4 and Fe2O3.

Study of Initial Corrosion Behaviors of Pure Copper under Simulated Marine Atmosphere

2012 ◽  
Vol 531 ◽  
pp. 51-54
Author(s):  
Jing Ping Xin ◽  
Zhuo Yuan Chen ◽  
Bao Rong Hou
Keyword(s):  
Electrochemical Impedance ◽  
Pure Copper ◽  
Corrosion Current ◽  
Cell System ◽  
Marine Atmosphere ◽  
Initial Exposure ◽  
Time Constants ◽  
Electrochemical Tests ◽  
Copper Electrodes ◽  
Corrosion Behaviors

The corrosion behaviors of pure copper were studied in initial exposure to a simulated marine atmosphere. A two-electrode cell system with two identical pure copper plates had been employed in electrochemical tests of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The copper electrodes were deposited with 70 µg cm-2 NaCl particles and then exposed in a humidified pure air of 97% RH at 25 °C. The time-evolution of corrosion current density obtained from the cathodic polarization curves had a trend of firstly decreasing, then increasing and finally getting a relative stable stage. The EIS data showed that the transition of two time constants corrosion stage to three time constants corrosion stage. The initial atmospheric corrosion behaviors of pure copper could be divided into three stages, including rapid corrosion stage, diminished corrosion stage and balanced corrosion stage.

scholarly journals Glass-Forming Ability and Corrosion Resistance of Al88Y8−xFe4+x (x = 0, 1, 2 at.%) Alloys

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1581
Author(s):  
Rafał Babilas ◽  
Monika Spilka ◽  
Katarzyna Młynarek ◽  
Wojciech Łoński ◽  
Dariusz Łukowiec ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Analytical Techniques ◽  
Corrosion Current ◽  
Glass Forming Ability ◽  
Electrochemical Tests ◽  
Glass Forming ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Amorphous Structures ◽  
The Impact

The effect of iron and yttrium additions on glass forming ability and corrosion resistance of Al88Y8-xFe4+x (x = 0, 1, 2 at.%) alloys in the form of ingots and melt-spun ribbons was investigated. The crystalline multiphase structure of ingots and amorphous-crystalline structure of ribbons were examined by a number of analytical techniques including X-ray diffraction, Mössbauer spectroscopy, and transmission electron microscopy. It was confirmed that the higher Fe additions contributed to formation of amorphous structures. The impact of chemical composition and structure of alloys on their corrosion resistance was characterized by electrochemical tests in 3.5% NaCl solution at 25 °C. The identification of the mechanism of chemical reactions taking place during polarization test along with the morphology and internal structure of the surface oxide films generated was performed. It was revealed that the best corrosion resistance was achieved for the Al88Y7Fe5 alloy in the form of ribbon, which exhibited the lowest corrosion current density (jcorr = 0.09 μA/cm2) and the highest polarization resistance (Rp = 96.7 kΩ∙cm2).

Exergy Analysis of a Hybrid Micro Gas Turbine Fuel Cell System Based on Existing Components

2012 ◽  
Author(s):  
D. P. Bakalis ◽  
A. G. Stamatis
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Exergy Analysis ◽  
Cell System ◽  
System Component ◽  
Utilization Factor ◽  
Fuel Cell Stack ◽  
Micro Gas Turbine ◽  
Partial Load ◽  
Set Up

A hybrid system based on an existing recuperated microturbine and a pre-commercially available high temperature tubular solid oxide fuel cell is modeled in order to study its performance. Individual models are developed for the microturbine and fuel cell generator and merged into a single one in order to set up the hybrid system. The model utilizes performance maps for the compressor and turbine components for the part load operation. The full and partial load exergetic performance is studied and the amounts of exergy destruction and efficiency of each hybrid system component are presented, in order to evaluate the irreversibilities and thermodynamic inefficiencies. Moreover, the effects of various performance parameters such as fuel cell stack temperature and fuel utilization factor are investigated. Based on the available results, suggestions are given in order to reduce the overall system irreversibility. Finally, the environmental impact of the hybrid system operation is evaluated.

Electrochemical cell system for voltammetry of high purity solvents

2000 ◽  
Vol 71 (2) ◽  
pp. 516-518 ◽  
Author(s):  
Michael A. May ◽  
Vijay K. Gupta ◽  
Karen Hounsokou
Keyword(s):  
High Purity ◽  
Electrochemical Cell ◽  
Cell System
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