Microstructural analysis and corrosion behavior of Fe, B, and Fe-B-modified Cu-Zn-Al shape memory alloys

2017 ◽  
Vol 35 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Kenneth Kanayo Alaneme ◽  
Eloho Anita Okotete ◽  
Michael Oluwatosin Bodunrin
Keyword(s):  
Corrosion Behavior ◽  
Microstructural Analysis ◽  
Corrosion Current ◽  
Al Alloys ◽  
Electrochemical Technique ◽  
Al Alloy ◽  
Casting Method ◽  
Sem Images ◽  
Current Densities ◽  
Corrosion Mechanisms

AbstractThe corrosion behavior of Cu-Zn-Al alloys modified with Fe, B, and Fe-B was investigated. This was motivated by the need to verify the effect of microalloy additions on the corrosion behavior of Cu-Zn-Al alloys, which, as recent study suggests, impacts microstructural changes other than grain refinement. Cu-Zn-Al alloys were produced by casting method with and without the addition of microalloy elements. The alloys were subjected to thermomechanical treatment before machining of test samples for corrosion and microstructural analysis. Scanning electron microscopy (SEM) and polarization electrochemical technique were used for the study. From the results, increase in grain size and change in grain edge morphology was apparent for the modified Cu-Zn-Al alloys produced. In 3.5 wt.% NaCl and 0.3 m H2SO4 solutions, the corrosion current densities were dependent on the type and concentration of the microalloy addition. Essentially, the corrosion rates for the modified alloys were higher in 3.5 wt.% NaCl solution; in 0.3 m H2SO4 solution, the modified Cu-Zn-Al alloy grades were observed to be more resistant to corrosion. The corrosion mechanisms of the alloys in both solutions were not feasibly established from the SEM images, but the extent of corrosion product deposition was apparent.

Effects of chemical composition on the corrosion behavior of A7N01S-T5 Al alloys

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540025 ◽  
Author(s):  
Xiaomin Wang ◽  
Xiaoyao Liao ◽  
Chuanping Ma ◽  
Shufang Zhang ◽  
Yan Liu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Corrosion Behavior ◽  
Corrosion Current ◽  
Al Alloys ◽  
Chemical Compositions ◽  
Al Alloy ◽  
Electrochemical Test ◽  
Electrochemical Behaviors ◽  
Cu Content ◽  
Corrosion Pits

Corrosion behavior of 7N01 Al alloy is sensitive to chemical composition. In this paper, stress corrosion cracking (SCC) and electrochemical behaviors of A7N01S-T5 Al alloys with three different chemical compositions were investigated. The corrosion weight loss and corrosion pits depth statistics showed that Alloy #3 (4.53 wt .% Zn , 1.27% Mg , < 0.001% Cu , 0.24% Cr , 0.15% Zr ) possesses the best anti-SCC property, while Alloy #1 (4.54% Zn , 1.09% Mg , 0.102% Cu , 0.25% Cr , 0.15% Zr ) was the weakest one. The different SCC susceptibility was mainly related to the Cu content as Alloy #3 contains higher Cu than Alloys #1 and #2. Electrochemical test result showed that Alloy #3 has higher corrosion potential and lower corrosion current density than Alloys #1 and #2. It is believed that a trace Cu can significantly improve the SC resistance of Al alloy, mainly because that Cu element can reduce the potential difference between grain inside and grain boundaries.

Corrosion Behavior of Zr53.5Cu26.5Ni5Al12Ag3 Bulk Amorphous Alloy in 3.5% NaCl Solution

2011 ◽  
Vol 299-300 ◽  
pp. 427-431
Author(s):  
Yun Li ◽  
Shi Zhi Shang ◽  
Ming Cheng ◽  
Liang Xu ◽  
Shi Hong Zhang
Keyword(s):  
Corrosion Resistance ◽  
Amorphous Alloy ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Bulk Amorphous Alloy ◽  
Nacl Solution ◽  
Current Densities ◽  
Resistance Decrease

The corrosion behavior of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution was investigated by using potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results show that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the better corrosion resistance than its corresponding crystal alloy. During the bath in the 3.5% NaCl solution at 25°C, Zr53.5Cu26.5Ni5Al12Ag3 alloy has the lower corrosion current density than the corresponding crystal alloy. After 100h, the corrosion current densities of Zr53.5Cu26.5Ni5Al12Ag3 and the corresponding crystal alloy are 3.8415×10-8A/cm2 and 5.2827×10-7A/cm2, respectively. The results of EIS test indicate that Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy has the excellent corrosion resistance because passive film with stable structure formed on the surface in 3.5% NaCl solution. With an increase in the immersion time, the passive film becomes thicker. It leads to impedance resistance and corrosion resistance decrease. The surface of Zr53.5Cu26.5Ni5Al12Ag3 bulk amorphous alloy in 3.5% NaCl solution for 100h was analyzed by SEM and EDS. The results show that the corrosive pitting can be found at both the amorphous alloy and the corresponding crystal alloy. However, the amorphous alloy has the better corrosive pitting resistance than the crystal one because the corrosion products formed by selective dissolving of Zr and Al elements. Moreover, the addition of Ag element helps to improve the corrosion resistance of the amorphous alloy greatly.

scholarly journals Pitting Corrosion Behavior and Surface Microstructure of Copper Strips When Rolled with Oil-in-Water Emulsions

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7911
Author(s):  
Xudong Yan ◽  
Jianlin Sun
Keyword(s):  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Surface Defects ◽  
Interactive Effect ◽  
Rolling Direction ◽  
Corrosion Current ◽  
Surface Microstructure ◽  
Oil In Water ◽  
Current Densities ◽  
Corrosion Pits

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. It was found that the corrosion current densities of the rolled Cu strips increased with accumulated reduction, which also lowered the pitting potentials and weakened their corrosion resistances. Therefore, the corrosive tendency of Cu strips under different rolling reductions (ε) followed the order of ε0% < ε20.7% < ε50.6% < ε77.3%. The Cu surface easily reacted with chlorine, sulfur, and carbon components from O/W emulsions to generate pitting corrosion. Under the interactive effect of pitting corrosion and stress corrosion, pits expanded along the rolling direction. The aggregation of anions in surface defects, such as dislocations, metastable pits, and microcracks, further accelerated the pitting corrosion of the surface.

scholarly journals Effect of Negative Current on the Microstructure of Oxide Coatings Prepared by Hybrid Pulse Anodization

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 22
Author(s):  
Shuo Huang ◽  
Bailing Jiang ◽  
Cancan Liu ◽  
Qingying Shao ◽  
Hongtao Li
Keyword(s):  
Room Temperature ◽  
Al Alloy ◽  
Oxide Coatings ◽  
Sem Images ◽  
Small Thickness ◽  
Anodization Time ◽  
Negative Current ◽  
Distribution Uniformity ◽  
Current Densities ◽  
6061 Al Alloy

The oxide coatings were prepared on 6061 Al alloy at different negative current densities in oxalic acid using the hybrid pulse anodization (HPA) method at room temperature. The variation curves of positive and negative voltages with anodization time were recorded. The nanopore diameters and distribution regularities in HPA coatings were analyzed with the Image-Pro Plus software based on field-emission scanning electron microscope (FE-SEM) images. The results showed that the negative current could reduce the growth rate of HPA coatings, and thus led to a small thickness of the coatings within the same anodization time. Besides, appropriate negative current densities resulted in the better distribution uniformity of nanopores, but the excessive negative current densities tended to cause inferior nanopore arrangement. These were attributed to the existence of the negative current, causing H+ and O2− to move in opposite directions, so that a large number of H+ concentrated on the surface of the HPA coatings, resulting in the accelerated dissolution of the coatings.

Influence of Vacuum Heat Treatment and Salt-Bath Nitrocarburization on the Corrosion Behavior of JIS SKD61 and DH31S Hot Work Steels

2010 ◽  
Vol 154-155 ◽  
pp. 1165-1169
Author(s):  
Shu Hung Yeh ◽  
Liu Ho Chiu ◽  
Wan Chung Lo ◽  
Chien Lung Huang
Keyword(s):  
Corrosion Behavior ◽  
Microstructural Analysis ◽  
Corrosion Current ◽  
Compound Layer ◽  
Salt Bath ◽  
Corrosion Properties ◽  
Electrochemical Tests ◽  
Martensitic Microstructure ◽  
Ε Phase ◽  
Ferrite Substrate

The corrosion behavior of the nitrocarburized JIS SKD61 and DH31S hot work steels has been investigated. The as received JIS SKD61 and DH31S steel was quenched and tempered to obtain the tempered martensitic microstructure. The nitrocarburizing treatment was conducted in a 570°C salt bath for 40, 80, and 120 minutes, respectively. Treated specimens were characterized by means of microstructural analysis, microhardness measurements, X-ray diffraction analysis, glow discharge spectrometer analysis and electrochemical tests in a 3.5wt% NaCl aerated solution. The thickness of compound layer of nitrocarburized specimens was about 1-3μm, and the microhardness is in the range between 790 – 820 HV0.05. The compound layer of the nitrided specimen was consisted of ε-phase (Fe2-3N) and the γ’-phase (Fe4N). The highest corrosion potential (Ecorr) in this study reached to -0.3 V for NC-S80 and NC-H80 specimen, it’s about 1.5 times higher than that of ferrite substrate. There is no evident difference on corrosion current density (Icorr) with prolonging nitrocarburizing treatment for both steels. Nevertheless, the corrosion properties were improved by nitrocarburizing process.

scholarly journals Electrochemical synthesis and corrosion behavior of thin polyaniline film on mild steel, copper and aluminum

2011 ◽  
Vol 65 (1) ◽  
pp. 15-21
Author(s):  
Ali Elkais ◽  
Milica Gvozdenovic ◽  
Branimir Jugovic ◽  
Tomislav Trisovic ◽  
Miodrag Maksimovic ◽  
...  
Keyword(s):  
Mild Steel ◽  
Anodic Oxidation ◽  
Corrosion Behavior ◽  
Electrochemical Synthesis ◽  
Sodium Benzoate ◽  
Corrosion Current ◽  
Protection Efficiency ◽  
Polarization Technique ◽  
Polyaniline Films ◽  
Current Densities

The electrochemical synthesis of polyaniline (PANI) on mild steel, aluminum and copper from the sodium benzoate solutions has been investigated. It has been shown that thin, highly adherent, polyaniline films on the investigated metals could be obtained by anodic oxidation with current densities in the range of 0.5 and 1.5 mA cm-2. The corrosion behavior of mild steel, aluminum and copper with polyaniline coating in 0.5 mol dm3 NaCl (pH 3) solutions, has been investigated by polarization technique. The corrosion current densities, porosity and protection efficiency was determined. It has been shown that polyaniline coating provided corrosion protection of all mentioned metals.

Corrosion Behavior of Cu50Zr40Ti10 Metallic Glass in HCl and NaCl

2013 ◽  
Vol 643 ◽  
pp. 33-36
Author(s):  
Wei Ke An ◽  
An Hui Cai ◽  
Guo Jun Zhou ◽  
Yun Luo ◽  
Tie Lin Li ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Corrosion Behavior ◽  
Corrosion Potential ◽  
Chloride Ion ◽  
Corrosion Current ◽  
Ion Concentration ◽  
Nacl Solution ◽  
Current Densities

The corrosion behavior of Cu50Zr40Ti10 (at. %) in HCl and NaCl solutions was investigated. The corrosion current densities icorr in HCl and NaCl solutions increase with increasing Clconcentration when the Cl- concentration is <0.5 molL-1, then continuously increase in the former and decrease in the latter. The icorr is larger in the latter than in the former when the Clconcentration is <0.5 molL-1, while inversely for in 1 molL-1 Cl- solution. The corrosion potential Ecorr decreases with increasing Cl- concentration in HCl. However, the change of the Ecorr vs. the chloride ion concentration in NaCl solution appears down-up-down.

Corrosion of Fe3Al-4Cr Alloys at 1000°C in N2-0.1%H2S Gas

2018 ◽  
Vol 765 ◽  
pp. 173-177 ◽  
Author(s):  
Yu Ke Shi ◽  
Dong Bok Lee
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Xrd Analysis ◽  
Al Alloys ◽  
Corrosion Products ◽  
Al Alloy ◽  
Oxide Scales ◽  
Mixed Gas ◽  
Corrosion Rates

Pure Fe3Al and Fe3Al+4%Cr alloys were corroded at 1000 °C for up to 200 h in N2-0.1%H2S-mixed gas in order to study their corrosion behavior in H2S-containing atmosphere. The formed scales consisted primarily of α-Al2O3, FeAl2O4, and Fe2O3. In these oxide scales, hydrogen and sulfur dissolved according to the reaction; H2S→2H+S. Corrosion products of Cr were not identified in the scales from the XRD analysis, indicating that Cr dissolved in the oxide scales. Fe3Al+4%Cr alloy displayed poorer corrosion resistance than Fe3Al alloy, indicating that chromium accelerated the corrosion rates of Fe3Al alloys.

Elevated electrochemical corrosion behavior of a B4C/Al neutron absorber by shot peening modification

2017 ◽  
Vol 24 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Linlin Zhang ◽  
Wenxian Wang ◽  
Baocheng Wang ◽  
Peng Zhang ◽  
Hongsheng Chen
Keyword(s):  
Corrosion Behavior ◽  
Shot Peening ◽  
High Speed ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Hardness Test ◽  
Corrosion Current ◽  
Al Alloy ◽  
Neutron Absorber ◽  
Modified Layer

AbstractThe shot peening (SP) method was employed to modify the surface properties of 33% B4C/Al composites. The microhardness, morphology, and corrosion behavior of B4C/Al composites were characterized by using the Vickers hardness test, scanning electron microscopy, potential dynamic scanning, and electrochemical impedance spectroscopy. The experimental observations revealed that the B4C particles were embedded into the matrix, which rendered the plastic deformation of Al alloy near the surface of B4C/Al composites on the condition of the high-speed impact of projectiles. As such, the density and hardness of the B4C/Al composite modified layer near the surface were enhanced. After the SP treatment, the results of the electrochemical polarization curve test showed that the corrosion potential increased by 55.2 mV, the corrosion current changed from 3.828×10-6 to 1.102×10-6 A/cm2, and the corrosion rate decreased by 72.2%, respectively. This indicates that the corrosion resistance significantly improved via the SP treatment. The mechanism of the formation of Al alloy modified layer and electrochemical corrosion behaviors is discussed in detail.

scholarly journals Manufacturing of Ti-6%Al and Ti-6%Al-4%V Alloys and Their Corrosion in Sodium Chloride Solutions

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 181 ◽  
Author(s):  
Hany S. Abdo ◽  
El-Sayed M. Sherif ◽  
Hamed A. El-Serehy
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Al Alloy ◽  
Spectroscopic Techniques ◽  
Uniform Corrosion ◽  
X Ray Diffraction ◽  
Current Time ◽  
X Ray ◽  
Sodium Chloride Solutions

The current research aims at the manufacturing of Ti-6%Al alloy and Ti-6%Al-4%V alloy using the mechanical alloying method and studying their corrosion behavior after various periods of immersions in 3.5% NaCl solutions. The fabricated alloys were also evaluated using spectroscopic techniques such as X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses. The corrosion behavior was studied using potentiodynamic polarization, electrochemical impedance spectroscopy, and chronoamperometric current-time electrochemical methods. It is confirmed that the presence of 4% V greatly decreases the uniform corrosion of the Ti-6%Al alloy as a result of the role of V in decreasing the cathodic, anodic, and corrosion current, and the rate of corrosion along with increasing the corrosion resistance. Increasing the time of immersion to 24 h and further to 48 h highly decreased the corrosion of the alloys. The presence of 4% V and extending the time of exposure thus increase the resistance against corrosion via decreasing the corrosion of Ti-6%Al alloy in the chloride test solution.

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