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 ◽  
...  

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.

2018 ◽  
Vol 69 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Ioana Arina Gherghescu ◽  
Daniela Ionita ◽  
Sorin Ciuca ◽  
Ruxandra Elena Dumitrescu

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.


2011 ◽  
Vol 284-286 ◽  
pp. 1701-1704
Author(s):  
Jing Ling Ma ◽  
Jiu Ba Wen ◽  
Gao Lin Li

The corrosion behavior of Al-5Zn-0.03In and Al-5Zn-0.03Ga alloys in 3.5 % NaCl solution has been examined by electrochemical methods, scanning electron microscopy, X-ray microanalysis, electrochemical impedance spectroscopy. The results demonstrate that the alloys differ in the microstructure, corroded morphology and electrochemical properties. For Al-5Zn-0.03In alloy, the precipitates enriched in Al and Zn initiates pitting. For Al-5Zn-0.03Ga alloy, corrosion occurs more uniformly, the corrosion of the alloy occurred via the formation of a surface Ga-Al amalgam alloy. The EIS of Al-5Zn-0.03In alloy contains a capacitive loop and an inductive loop; the inductive loop can be attributed to the presence of the pitting. The EIS of Al-5Zn-0.03Ga alloy contains only a capacitive loop.


2012 ◽  
Vol 189 ◽  
pp. 36-39
Author(s):  
Hai Jiao Yang ◽  
Sheng Tao Zhang ◽  
Lei Zhang

The corrosion behavior of copper in halide solutions was investigated by cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). On this basis, the mechanism of electrochemical corrosion behavior of Cu in halide solutions has been analyzed. The study explores the corrosive effect of the halide ions on copper materials and provides a theoretical basis for the inhibition of halide ions on the corrosion of copper materials.


2014 ◽  
Vol 624 ◽  
pp. 77-81
Author(s):  
Zhi Lin Wu ◽  
Duo Xiang Wu ◽  
Ren Shu Yuan ◽  
Lei Zhao ◽  
Yan Bao Zhao

The corrosion behavior of hydrostatic extruded tube AZ80 magnesium alloy was investigated by polarization curves and electrochemical impedance spectroscopy (EIS) in simulated atmosphere. The results indicated that, the corrosion resistance of the hydrostatic extruded AZ80 magnesium alloy with uneven deformed grains and increased sub-grains were obviously weakened, with larger corrosion current density in the polarization curves and lower corrosion resistances in the electrochemical impedance spectroscopy plots. This was mainly because of the hydrostatic extrusion which made AZ80 magnesium alloy within large numbers of dislocation tangles. So the residual stress increased the electrochemical activity of magnesium alloy which reduced the corrosion resistance of magnesium alloys.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1172
Author(s):  
Polina Metalnikov ◽  
Guy Ben-Hamu ◽  
Kwang Seon Shin ◽  
Amir Eliezer

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.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 986
Author(s):  
Jozef Minda ◽  
Stanislava Fintová ◽  
Branislav Hadzima ◽  
Pavel Doležal ◽  
Michaela Hasoňová ◽  
...  

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.


CORROSION ◽  
10.5006/3490 ◽  
2021 ◽  
Author(s):  
Caiyun Bai ◽  
Peifeng Li ◽  
Tieqiang Gang ◽  
Jian Li ◽  
Min Wei ◽  
...  

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.


2020 ◽  
Vol 10 (13) ◽  
pp. 4568
Author(s):  
Hany S. Abdo ◽  
Asiful H. Seikh ◽  
Jabair A. Mohammed ◽  
Monis Luqman ◽  
Sameh A. Ragab ◽  
...  

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.


2021 ◽  
Vol 904 ◽  
pp. 519-524
Author(s):  
Gui Yun Zhang ◽  
Yong Wang ◽  
Tian Wei Zhang ◽  
Chen Yu Zhao

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.


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