Corrosion Resistance of 2060 Aluminum–Lithium Alloy LBW Welds Filled with Al-5.6Cu Wire

Alloy sheets of type 2060 aluminum–lithium were welded by laser beam welding (LBW) filled with ER2319 Al-5.6Cu wire. Microstructural observations showed the uneven distribution of columnar grains, equiaxed grains and equiaxed dendrite grains in the weld. The θ′(Al2Cu) phase and other phases precipitated in the weld. The θ′(Al2Cu) phase centrally distributed at the grain boundaries. During the immersion corrosion, the pitting corrosion first occurred and then gradually expanded and transformed to intergranular corrosion and exfoliation corrosion. The electrochemical corrosion test showed a higher corrosion tendency of the base metal and heat-affected zone for the lower corrosion potential, but the corrosion current density of the weld was relatively larger. The segregation of Cu, Mg and other elements at the grain boundary aggravated the occurrence of intergranular corrosion.

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Corrosion Resistance of Rare Earth Modified Chromizing Coating on P110 Oil Casing Tube Steel by Pack Cementation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1075 ◽

2009 ◽

Vol 79-82 ◽

pp. 1075-1078

Author(s):

Nai Ming Lin ◽

Fa Qin Xie ◽

Tao Zhong ◽

Xiang Qing Wu ◽

Wei Tian

Keyword(s):

Corrosion Resistance ◽

Rare Earth ◽

Steel Substrate ◽

Electrochemical Corrosion ◽

Corrosion Current ◽

Pack Cementation ◽

Tube Steel ◽

X Ray ◽

Immersion Corrosion ◽

P110 Steel

The rare earth (RE) modified chromizing coating was obtained on P110 oil casing tube steel (P110 steel) substrate by means of pack cementation technique to enhance the resistance against corrosion of P110 steel. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) were employed to research microstructure, composition distribution and phase constitution of the chromizing coating. The effect of minor addition of RE on the microstructure of chromizing was discussed. Corrosion resistance of chromizing coating was investigated and compared with that of bare P110 steel via electrochemical corrosion and immersion corrosion in simulated oilfield brine solution, respectively. The results showed that a uniform, continuous and compact coating was formed on P110 steel. The coating with RE addition was more compact than that of the coating added no RE, and a small amount of RE addition could promote the chromizing procedure notably. From SEM and EDX investigation, it had been confirmed that the coating was composed of two different layers, an out layer and an inner layer; the coating mainly contains Fe and Cr; the concentration of Cr decreased as the distance from the surface increased, yet Fe presented the inverse trend. XRD analysis indicated the coating was built up by (Cr, Fe)23C6 referring to the out layer, (Cr, Fe)7C3, Cr7C3 and α-(Cr, Fe) corresponding to the inner layer. Electrochemical corrosion consequence was obtained as follows: the self-corroding electric potential of chromizing coating was higher, and the corrosion current density was lower than that of bare P110 steel, which revealed that chromizing coating had better anti-corrosion performance; immersion corrosion results demonstrated the mass loss of chromized P110 steel was lower, and this meant that chromizing coating had a better corrosion resistance than that of bare P110 steel on the experimental condition. A compact (Cr, Fe)xCy coating can be fabricated by pack cementation technique. As a result of minor RE addition, microstructure and corrosion resistance of the chromizing coating are improved obviously.

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Formation of SUS304/Aluminum Alloys Using Wire and Arc Additive Manufacturing

Metals ◽

10.3390/met8080595 ◽

2018 ◽

Vol 8 (8) ◽

pp. 595 ◽

Cited By ~ 2

Author(s):

Zhizhuang Hao ◽

Sansan Ao ◽

Yangchuan Cai ◽

Wei Zhang ◽

Zhen Luo

Keyword(s):

Additive Manufacturing ◽

Aluminum Alloys ◽

Pulse Current ◽

Electrochemical Corrosion ◽

Travel Speed ◽

Constant Current ◽

Tensile Fracture ◽

Columnar Grains ◽

Metallographic Observation ◽

Equiaxed Grains

In this study, wire and arc additive manufacturing (WAAM) was used to form SUS304/aluminum alloys. The buildup wall was well shaped using a pulse current consisting of a base current of 150 A and peak current of 200 A and a 0.2 m/min travel speed. Metallographic observation revealed that the original grains were columnar grains and transformed into equiaxed grains in the top area. The increased content of alloying elements in the fused layer improved the hardness of the buildup wall. The buildup wall formed using pulsed current exhibited improved anti-electrochemical corrosion performance when compared with that formed using constant current. The tensile strength of the alloy decreased but its elongation increased compared with those of Fe-Al alloys. The tensile fracture along the fusing direction was plastic fracture. However, the tensile fracture perpendicular to the fusing direction consisted of a combination of plastic and brittle fracture.

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Effects of Temperature on Corrosion Behavior of X70 Steel in Halons

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.996 ◽

2011 ◽

Vol 311-313 ◽

pp. 996-1000 ◽

Cited By ~ 1

Author(s):

Jing Xu ◽

Jian Wei Yang ◽

Jian Ping Cao ◽

Chen Chen

Keyword(s):

Corrosion Behavior ◽

Polarization Curve ◽

Corrosion Test ◽

Electrochemical Impedance ◽

Pipeline Steel ◽

Electrochemical Corrosion ◽

Corrosion Current ◽

X70 Pipeline Steel ◽

Cathode Reaction ◽

Immersion Corrosion

The corrosion behavior of X70 pipeline steel in 0.5% NaC1 solution in different temperature of 25°C、35°C and 55°C was studied by dynamic potential polarization curve and electrochemical impedance spectroscopy（EIS）method. The corrosion topography of X70 pipeline steel in normal temperature and 30°C was also compared in immersion corrosion test after 25 days. The results show that when the temperature rises, the corrosion current density Icorr increases, the linear polarization resistance reduces, cathode polarization curve right shift, caused corrosion rate increases which primarily by the increasing the transmission of reactant in the cathode reaction. Pitting corrosion developed after 25 days immersion corrosion in 30°C solution which proved the promoter action of temperature to pit corrosion, and which is agreed with the electrochemical corrosion test results.

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

Metals ◽

10.3390/met11081317 ◽

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.

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Microstructure of Al-5Cu-1Li-0.6Mg-0.5Ag-0.5Mn Alloys

Metals ◽

10.3390/met11010037 ◽

2020 ◽

Vol 11 (1) ◽

pp. 37

Author(s):

Wenzheng Chen ◽

Wenlong Zhang ◽

Dongyan Ding ◽

Daihong Xiao

Keyword(s):

Mechanical Properties ◽

Corrosion Current Density ◽

Corrosion Potential ◽

Aging Treatment ◽

Corrosion Current ◽

Homogenization Temperature ◽

Tafel Polarization ◽

Al2cu Phase ◽

Different Temperatures ◽

Microstructural Optimization

Microstructural optimization of Al-Li alloys plays a key role in the adjustment of mechanical properties as well as corrosion behavior. In this work, Al-5Cu-1Li-0.6Mg-0.5Ag-0.5Mn alloy was homogenized at different temperatures and holding times, followed by aging treatment. The microstructure and composition of the homogenized alloys and aged alloys were investigated. There were Al7Cu4Li phase, Al3Li phase, and Al2CuLi phases in the homogenized alloys. The Al7Cu4Li phase was dissolved with an increase in homogenization temperature and holding time. Al2Cu phase and Al2CuLi phase coarsened during the homogenization process. The alloy homogenized at 515 °C for 20 h was subjected to a two-stage aging treatment. Peak-age alloy, which had gone through age treatment at 120 °C for 4 h and 180 °C for 6 h, was mainly composed of α-Al, Al20Cu2Mn3, Al2CuLi, Al2Cu, and Al3Li phases. Tafel polarization of the peak-age alloys revealed the corrosion potential and corrosion current density to be −779 mV and 2.979 μA/cm2, respectively. The over-age alloy had a more positive corrosion potential of −658 mV but presented a higher corrosion current of 6.929 μA/cm2.

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Electrochemical and Salt Spray Corrosion Behavior of Copper Alloy Contact Wires in Chloride Solution

Materials Science Forum ◽

10.4028/www.scientific.net/msf.789.622 ◽

2014 ◽

Vol 789 ◽

pp. 622-626

Author(s):

Peng Chao Zhang ◽

Jian Zhang ◽

Jin Chuan Jie ◽

Yuan Gao ◽

Yong Dong ◽

...

Keyword(s):

Corrosion Behavior ◽

Corrosion Test ◽

Chloride Solution ◽

Copper Alloys ◽

Salt Spray ◽

Electrochemical Corrosion ◽

Corrosion Current ◽

Corrosion Mechanism ◽

Salt Spray Corrosion ◽

Surface Morphologies

The effect of different alloying elements on corrosion behavior of copper alloys was investigated using electrochemical corrosion and salt spray corrosion test in NaCl solution. Cu-Ag has the most stable corrosion current in the potentiostatic scanning test, exhibiting a better corrosion resistant performance. It can be analyzed from corrosion surface morphologies that Cu-Ag presents exfoliation corrosion mechanism while Cu-Sn shows crevice corrosion mechanism. Cu-Mg has a complex corrosion process caused by multiple corrosion mechanism. In the salt spray corrosion test, the corrosion degree of Cu-Ag is lighter than those of Cu-Sn and Cu-Mg after 24h test. Therefore, the Cu-Ag alloy exhibits the best corrosion resistance in chloride solution.

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Formation of Grain Structures of Thermal Sprayed Nickel Coatings and the Coating Properties

Materials Science Forum ◽

10.4028/www.scientific.net/msf.502.517 ◽

2005 ◽

Vol 502 ◽

pp. 517-0

Author(s):

Kenji Murakami

Keyword(s):

Steel Substrate ◽

Nickel Coatings ◽

Grain Structures ◽

Heat Treated ◽

Columnar Grains ◽

Different Temperatures ◽

Plasma Sprayed ◽

Equiaxed Grains ◽

Sprayed Coatings ◽

Lamellar Interfaces

Pure nickel powder was low pressure plasma sprayed onto a steel substrate held at different temperatures during spraying. The as-sprayed coatings consist of columnar grains whose axes are nearly perpendicular to the lamellae composing the coatings. As the coating temperature becomes higher, the length of the columnar grains increases and is longer than the thickness of the lamellae, indicating the growth of the grains across the lamellar interfaces during spraying. On the other hand, the coatings that were heat treated after spraying consist of coarse equiaxed grains. The coatings that experienced high temperatures during spraying or the heat treated coatings have large porosity and contain large globular pores. The hardness, apparent density and the tensile strength of the coating itself were the highest for the coating prepared at a low temperature and became low on heat treatment. The thermal conductivity in the direction perpendicular to the coating was the largest for the coating that consisted of long columnar grains.

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

Engineering review ◽

10.30765/er.1577 ◽

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.

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