scholarly journals Electrochemical Corrosion Behavior of Pure Mg Processed by Powder Metallurgy

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 986
Author(s):  
Jozef Minda ◽  
Stanislava Fintová ◽  
Branislav Hadzima ◽  
Pavel Doležal ◽  
Michaela Hasoňová ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Corrosion Products ◽  
Uniform Corrosion ◽  
Electrochemical Corrosion Behavior ◽  
Powder Particles ◽  
Mechanical Bonding

Pure Mg samples were prepared by powder metallurgy using the cold and hot compacting methods. Cold compacted pure Mg (500 MPa/RT) was characterized by 5% porosity and the mechanical bonding of powder particles. Hot compacted samples (100 MPa/400 °C and 500 MPa/400 °C) exhibited porosity below 0.5%, and diffusion bonding combined with mechanical bonding played a role in material compaction. The prepared pure Mg samples and wrought pure Mg were subjected to corrosion tests using electrochemical impedance spectroscopy. Similar material corrosion behavior was observed for the samples compacted at 500 MPa/RT and 100 MPa/400 °C; however, hot compacted samples processed at 500 MPa/400 °C exhibited longer corrosion resistance in 0.9% NaCl solution. The difference in corrosion behavior was mainly related to the different binding mechanisms of the powder particles. Cold compacted samples were characterized by a more pronounced corrosion attack and the creation of a porous layer of corrosion products. Hot compacted samples prepared at 500 MPa/400 °C were characterized by uniform corrosion and the absence of a layer of corrosion products on the specimen surface. Powder-based cold compacted samples exhibited lower corrosion resistance compared to the wrought pure Mg, while the corrosion behavior of the hot compacted samples prepared at 500 MPa/400 °C was similar to that of wrought material.

Thermal Parameters Influence Assessed by Electrochemical Impedance Spectroscopy on a Ni50Ti48Nb2 Shape Memory Alloy

2018 ◽  
Vol 69 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Ioana Arina Gherghescu ◽  
Daniela Ionita ◽  
Sorin Ciuca ◽  
Ruxandra Elena Dumitrescu
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Transformation Temperatures ◽  
Electrochemical Corrosion Behavior

This paper presents some electrochemical impedance spectroscopy research results concerning the corrosion resistance of a shape memory Ni50Ti48Nb2 alloy. This one was previously studied by SEM and DSC [1,2] but some new research features had to be made clear in order to be able to explain its electrochemical corrosion behavior. The chemical composition Ni50Ti48Nb2 was chosen in order to obtain a shape memory alloy having a wider hysteresis than equiatomic NiTi, for the purpose of achieving a better thermomechanical stability. Cryogenic applications are aimed. After processing the cast ingot, two samples, S1 and S2, were further annealed at 800�C/12 h and, respectively, at 900�C/12h. Scanning electron micrographs together with the chemical elements mapping results were obtained. They were related to the previous results concerning the informations on the structure of the different phases found in this NiTiNb alloy: austenite, martensite and secondary phases, as well as some primary compounds [1,2]. Considering the size and shape of the complex precipitate particles of NiTiNb in the two differently heat treated samples, these were found responsible for some changes in the transformation temperatures [3] but the electrochemical corrosion behavior of the alloy seems to be influenced to a lesser extent by the heat treatments. Both samples exhibit good values of corrosion resistance, however S2 shows better values than S1. Thus lower transformation temperatures and a slightly better corrosion resistance make the Ni50Ti48Nb2 alloy annealed at 900�C/12h subsequently submitted to thermal cycling to be the right choice for producing couplings in the cryogenic industry.

Electrochemical Corrosion Behavior of Cu15Ni10Mn Alloy in NaCl Solution

2013 ◽  
Vol 341-342 ◽  
pp. 23-27
Author(s):  
Wei Cai ◽  
An Yun Li ◽  
Pian Xu ◽  
Yu Wu ◽  
Liang Chen ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Copper Chloride ◽  
Electrochemical Corrosion ◽  
Corrosion Products ◽  
Dissolution Mechanism ◽  
Nacl Solution ◽  
Electrochemical Corrosion Behavior

Investigating the electrochemical corrosion behavior of Cu15Ni10Mn alloy in NaCl solution with different Cl concentration was studied by measuring open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The results show that as the Cl- concentration increase, the corrosion potentials of the alloy shifted negatively, corrosion currents increase, the corrosion process by electrochemical control change of diffusion control, and therefore the corrosion rates become faster. The presence of Cl- have effect on the dissolution mechanism and corrosion products of the alloy, when the concentration of Cl- is relatively low, a reducing peak current appears in the process of cyclic voltammetry retracing , when the Cl- concentration is higher, cyclic voltammetry flyback process does not appear to restore the current peak. This is mainly associated with the generation of corrosion product, when Cl- concentration is low, the corrosion product is Cu2(OH)3Cl (basic copper chloride) and other two copper ion salts, when the concentration of Cl-is higher, corrosion products are mainly Cu2(OH)3Cl (basic copper chloride).

scholarly journals Effect of Ca Addition on Corrosion Behavior of Wrought AM60 Magnesium Alloy in Alkaline Solutions

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1172
Author(s):  
Polina Metalnikov ◽  
Guy Ben-Hamu ◽  
Kwang Seon Shin ◽  
Amir Eliezer
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Fuel Efficiency ◽  
Electrochemical Corrosion ◽  
Alkaline Solutions ◽  
Kelvin Probe ◽  
Ca Addition ◽  
Electrochemical Corrosion Behavior

Magnesium (Mg) alloys possess the lowest density among structural materials, and their application in the automotive and aircraft industries might enhance fuel efficiency. The mechanical properties can be improved by the addition of alloying elements. However, since Mg and its alloys are very susceptible to corrosion degradation, it is important to study the effect of these elements on the alloys’ corrosion behavior. In this study, 1 wt% of calcium (Ca) was added to wrought AM60 Mg alloy, and the electrochemical corrosion behavior of the alloys in alkaline solutions with and without Cl− ions was compared. The corrosion behavior was investigated by means of immersion tests, gravimetric measurements and potentiodynamic polarization (PDP); the characteristics of the oxide layer were studied by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The addition of Ca resulted in precipitation of the ternary aluminum-rich (Mg-Al)2Ca phase. Scanning Kelvin probe force microscope (SKPFM) identified that this phase has a cathodic behavior relative to the α-Mg matrix; hence it can serve as additional sites for initiation of pitting corrosion. As a result, the corrosion resistance of wrought AM60 alloy with 1 wt% Ca addition deteriorated in a NaCl solution. However, in the absence of Cl− ions, alloying with Ca improves the corrosion resistance of wrought AM60 alloy due to the stabilization of the corrosion products layer. The effect of long-period immersion time on the corrosion behavior and alloy oxidation is discussed.

scholarly journals Preparation, microstructure and property of zinc-substituted hydroxyapatite/magnesium biocomposite

2017 ◽  
Vol 49 (4) ◽  
pp. 399-407 ◽  
Author(s):  
Zhengquan Jia ◽  
Zuoxing Guo ◽  
Qiulin Wei ◽  
Jingjuan Li ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Crystallite Size ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Compression Tests ◽  
Corrosion Tests ◽  
Electrochemical Corrosion Behavior ◽  
Optimal Mechanical Property

Zinc-substituted hydroxyapatite (Zn-HA, Ca10-xZnx(PO4)6(OH)2) is used as the modified material of hydroxyapatite (HA, Ca10 (PO4)6(OH)2). In this work, Zn-HA with Zn contents of 10-30 mol% was used to produce Zn-HA/Mg composites by powder metallurgy. The calculated results showed that the crystallite size and lattice parameters of Zn-HA powders varied with the contents of 0-30 mol% Zn, confirming that the divalent Zn2+ ions can substitute Ca2+ ions in HA. Furthermore, the microstructure, mechanical property and electrochemical corrosion behavior of Zn-HA/Mg composites were investigated by SEM, compression tests, and electrochemical corrosion tests, respectively. The results indicate that the highest density and lowest porosity are obtained and the optimal mechanical property and corrosion resistance are achieved in the Zn-HA/Mg composites with 20 mol% Zn.

Influence of processing technology on electrochemical corrosion behavior of Ti-6Al-4V alloys

CORROSION ◽  
10.5006/3490 ◽  
2021 ◽  
Author(s):  
Caiyun Bai ◽  
Peifeng Li ◽  
Tieqiang Gang ◽  
Jian Li ◽  
Min Wei ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Electrochemical Impedance Spectra ◽  
Transfer Resistance ◽  
Electrochemical Corrosion Behavior ◽  
Corrosion Behaviors ◽  
3D Printed

Ti-6Al-4V alloys are typically used for biomedical implants, aerospace components and offshore equipment, where corrosion resistance is critical. In the present paper, the electrochemical corrosion behaviors of Ti-6Al-4V alloys made by different traditional processing and 3D printing technologies in seawater, 3.5 wt.% NaCl, 3.5 wt.% HCl, 5 wt.% HCl and 10 wt.% HCl solutions were studied through polarization curve and electrochemical impedance spectra (EIS) analyses. The influences of microstructure and printing parameters on the corrosion behaviors of Ti-6Al-4V alloys were analyzed. In addition, the corrosion current density, film resistance and charge transfer resistance of traditionally processed Ti-6Al-4V and 3D printed Ti-6Al-4V in the five solutions were compared. The results show that Ti-6Al-4V possesses a better corrosion resistance in seawater than in 3.5 wt.% NaCl, and that the corrosion rate increases with the HCl concentration. Besides, 3D printed Ti-6Al-4V shows a higher corrosion rate in comparison with traditionally processed Ti-6Al-4V because pores are effortless to enrich Cl-. Finally, the ratio of laser power to its scanning speed and the phase constituent composition of the alloy have slight influences on its electrochemical corrosion behavior. It is suggested that for the 3D printed alloy, the deterioration of mechanical properties induced by corrosion damage during servicing should be assessed and considered.

scholarly journals Influence of Chloride Ions on Electrochemical Corrosion Behavior of Dual-Phase Steel over Conventional Rebar in Pore Solution

2020 ◽  
Vol 10 (13) ◽  
pp. 4568
Author(s):  
Hany S. Abdo ◽  
Asiful H. Seikh ◽  
Jabair A. Mohammed ◽  
Monis Luqman ◽  
Sameh A. Ragab ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Pore Solution ◽  
Electrochemical Corrosion ◽  
Chloride Ions ◽  
Dual Phase ◽  
Good Corrosion Resistance ◽  
Main Challenge ◽  
Electrochemical Corrosion Behavior

Reinforced steel bars (rebar) are extensively used in construction, and the main challenge is in minimizing corrosion due to oxide or passive layer breakdown. In contrast, dual-phase (DP) steel has good corrosion resistance. This study investigated the effect of Cl− ions on the electrochemical corrosion behavior of DP rebar and conventional rebar. Corrosion behavior studies and electrochemical measurements were conducted on DP rebar and conventional rebar in simulated concrete pore solution with different concentrations of Cl− ions. Microstructure analysis, surface morphology analysis, and corroded surface characterization were performed using optical microscopy, field emission scanning electron microscopy, and Raman spectroscopy, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements revealed that DP rebar has good passivity, leading to better corrosion resistance and greater strength compared to ordinary rebar. In addition, DP rebar showed better passivity behavior compared to conventional rebar in alkaline solution. Therefore, the presence of a dual phase (ferrite and martensite) in reinforced concrete structured steel induces good corrosion resistance.

The Influence of Prepared Methods on Electrochemical Corrosion Behavior of Fe3Al Intermetallic

2014 ◽  
Vol 1033-1034 ◽  
pp. 1258-1262 ◽  
Author(s):  
Xia Wen Le ◽  
Dan Ji ◽  
Qing Dong Zhong ◽  
Qiong Yu Zhou ◽  
Tong Mo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Electrochemical Corrosion ◽  
X Ray ◽  
Electrochemical Corrosion Behavior ◽  
Structure And Microstructure ◽  
Scanning Electron

Different compositions to prepare the Fe3Al intermetallic were analyzed through the microstructure and electrochemical corrosion behavior. The structure and microstructure were analyzed by X-ray and scanning electron microstructure (SEM). The corrosion resistance of samples was evaluated by potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS). Results show that the alloy with a composition of pure aluminum with pure iron shows a higher corrosion resistance.

Corrosion Protection of Nano-Silica Powder Coatingon Artificial Seawater

2021 ◽  
Vol 904 ◽  
pp. 519-524
Author(s):  
Gui Yun Zhang ◽  
Yong Wang ◽  
Tian Wei Zhang ◽  
Chen Yu Zhao
Keyword(s):  
Corrosion Protection ◽  
Corrosion Behavior ◽  
Sea Water ◽  
Electrochemical Impedance ◽  
Water Solution ◽  
Electrochemical Corrosion ◽  
Artificial Seawater ◽  
Protection Effect ◽  
Aluminum Sheets ◽  
Electrochemical Corrosion Behavior

Sea water resources are extensive and can be used to extinguish fires, but their corrosiveness is a major problem. Using the method of electrochemical workstation, the electrochemical corrosion behavior of aluminum sheet in artificial sea water solution and silica-coated artificial seawater was studied; by analyzing the surface morphology, polarization curve and electrochemical impedance spectroscopy, the electrochemical corrosion behavior of aluminum sheets under different immersion times and different immersion media is obtained. The conclusion is that the coating of nanosilica powder has a certain corrosion protection effect on artificial seawater.

Electrochemical Corrosion Behavior of Different Graphite Shapes Cast Irons in Acidic Solution

2014 ◽  
Vol 906 ◽  
pp. 275-282
Author(s):  
Zhu Huan Yu ◽  
Jun Feng Qiang ◽  
Hui Lu Li
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Driving Force ◽  
Acidic Solution ◽  
Electrochemical Corrosion ◽  
White Iron ◽  
Cast Irons ◽  
The Matrix ◽  
Electrochemical Corrosion Behavior

The effect of graphite shapes on the electrochemical corrosion behavior of cast iron was studied by means of weight loss tests, electrochemical measurements and electron microscopy. It was found that the electrochemical corrosion behavior of graphite is significantly different from one other, and the corrosive potential difference between carbide ad the matrix is the main driving force of the different phase corrosions. Among them, the center A type and edge D type graphite exhibited the highest corrosion resistance. The corrosion of white iron is worst, because there are so many type carbides in white iron and so there is an obvious tendency to produce micro-cell in white iron.

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