scholarly journals Corrosion Behavior of AlFeCrCoNiZrx High-Entropy Alloys in 0.5 M Sulfuric Acid Solution

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1471
Author(s):  
Yuhong Yao ◽  
Yaohua Jin ◽  
Wei Gao ◽  
Xiaoyu Liang ◽  
Jian Chen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
General Corrosion ◽  
High Entropy Alloys ◽  
H2so4 Solution ◽  
High Entropy ◽  
Polarization Measurements ◽  
Selective Corrosion

AlCoCrFeNiZrx (x = 0, 0.1, 0.2, 0.3, and 0.5) high-entropy alloys (HEAs) were prepared by a non-consumable vacuum arc melting technology, and the microstructure and corrosion behavior were investigated by XRD, SEM, immersion tests, and electrochemical measurements. The results indicate that galvanic corrosion of the AlCoCrFeNiZrx alloys occurred in 0.5 M H2SO4 solution, and only 0.1 mol of the added Zr could greatly improve the corrosion resistance of the alloys. The corrosion properties of the AlCoCrFeNiZrx HEAs had similar change tendencies with the increase in the Zr content in the immersion tests, potentiodynamic polarization measurements, and electrochemical impedance analysis, that is, the corrosion resistance of the AlCoCrFeNiZrx alloys in a 0.5 M H2SO4 solution first increased and then decreased with the increase in the Zr content. The Zr0.1 alloys were found to have the best selective corrosion and general corrosion resistance with the smallest corrosion rate, whereas the Zr0.3 alloys presented the worst selective corrosion and general corrosion resistance with the highest corrosion rate from both the immersion tests and the potentiodynamic polarization measurements.

Corrosion Behavior of Pb-Ca-Sn Electrodes for Copper Electrowinning

2011 ◽  
Vol 402 ◽  
pp. 349-353
Author(s):  
Xue Tao Yuan ◽  
Xu Dong Lv ◽  
Zhi Qiang Hua ◽  
Lei Wang ◽  
Tao Li
Keyword(s):  
Corrosion Rate ◽  
Ternary Alloy ◽  
Corrosion Behavior ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Electrode Surface ◽  
Anodic Polarization ◽  
Polarization Measurements ◽  
Copper Electrowinning ◽  
Sn Anode

Anodic polarization behavior of ternary alloy Pb-0.08%Ca-1%Sn is studied by potentiodynamic polarization measurements, corrosion rate, the products on electrode surface after polarization, and microstructure of anode mud after polarization in electrowinning cell. The results show that Pb-Ca-Sn anode is easy to be passivated in electrolyte for copper electrowinning, the maintaining passivity current density is 97.72 µA•cm-2and the corrosion products on the surface of Pb-Ca-Sn electrode present loose scaly, being composed of α-PbO2, β- PbO2and PbSO4after polarization.

scholarly journals De-alloying Behavior of Mg–Al alloy in Sulphuric Acid and Acetic Acid Aqueous Solutions

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2046 ◽  
Author(s):  
Yonggang Li ◽  
Yinghui Wei ◽  
Shengqiang Yang
Keyword(s):  
Acetic Acid ◽  
Aqueous Solutions ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Eutectic Phase ◽  
Al Alloy ◽  
General Corrosion ◽  
H2so4 Solution ◽  
Corrosion Characteristic ◽  
Selective Corrosion

The fabricated Mg–Al alloy consists of α-Mg phase and Mg–Mg17Al12 eutectic phase. The corrosion behavior of cast Mg–Al alloy in sulphuric acid (H2SO4) and acetic acid (HAc) aqueous solutions was investigated. The Mg–Al alloy shows general corrosion in H2SO4 solution, and the α-Mg dendrites revealed a slightly faster corrosion rate than that of the eutectics. In HAc solution, the alloy shows an obvious selective corrosion characteristic, with the α-Mg dendrites being corroded preferentially. Grain orientation plays an important role in corrosion behavior of the alloy in the HAc solutions.

Effect of Al on Corrosion Behavior in 3.5%NaCl Solution of AlxCoCrFeNi High Entropy Alloys

2021 ◽  
Vol 53 ◽  
pp. 20-30
Author(s):  
Victor Geantă ◽  
Ionelia Voiculescu ◽  
Mihai Cosmin Cotrut ◽  
Maria Diana Vrânceanu ◽  
Ion Mihai Vasile ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Metallic Matrix ◽  
Corrosion Current ◽  
Metal Corrosion ◽  
High Entropy Alloys ◽  
Nacl Solution ◽  
High Entropy ◽  
Arc Melting

The high entropy alloys have attracted the interest of material scientists due to theirspecial mechanical properties and a very good corrosion behavior. The corrosion resistance is provided by the formation of a passive, thin and compact oxide film that prevents the chemical dissolution of the metallic matrix. The effect of aluminum in AlxCrFeCoNi high entropy alloys (with x = 1; 1.5 and 2) that were obtained by electric arc melting under argon atmosphere has been studied in the paper. In order to understand the processes involved in metal corrosion, the alloys have been tested by polarization resistance method in 3.5% NaCl solution and main corrosion parameters have been analyzed (i.e. corrosion potential; corrosion current density; corrosion rate and polarization resistance). The surfaces of the corroded samples were examined by scanning electron microscopy to estimate the effect of the chemical composition on corrosion resistance. The corrosion tests have shown that the corrosion resistance of the HEA decreases by increasing the aluminum content from about 15 at.% to 32 at. % Al and reducing the chromium content from 28 at. % to 18 at.% Cr.

scholarly journals Effect of Molybdenum on the Corrosion Behavior of High-Entropy Alloys CoCrFeNi2 and CoCrFeNi2Mo0.25 under Sodium Chloride Aqueous Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Alvaro A. Rodriguez ◽  
Joseph H. Tylczak ◽  
Michael C. Gao ◽  
Paul D. Jablonski ◽  
Martin Detrois ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sodium Chloride ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Electrochemical Impedance ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
High Entropy Alloys ◽  
Stainless Steel 316L ◽  
High Entropy

The corrosion behavior of high-entropy alloys (HEAs) CoCrFeNi2 and CoCrFeNi2Mo0.25 was investigated in 3.5 wt. percent sodium chloride (NaCl) at 25°C by electrochemical methods. Their corrosion parameters were compared to those of HASTELLOY® C-276 (UNS N10276) and stainless steel 316L (UNS 31600) to assess the suitability of HEAs for potential industrial applications in NaCl simulating seawater type environments. The corrosion rates were calculated using corrosion current determined from electrochemical experiments for each of the alloys. In addition, potentiodynamic polarization measurements can indicate active, passive, and transpassive behavior of the metal as well as potential susceptibility to pitting corrosion. Cyclic voltammetry (CV) can confirm the alloy susceptibility to pitting corrosion. Electrochemical impedance spectroscopy (EIS) elucidates the corrosion mechanism under studied conditions. The results of the electrochemical experiments and scanning electron microscopy (SEM) analyses of the corroded surfaces revealed general corrosion on alloy CoCrFeNi2Mo0.25 and HASTELLOY C-276 and pitting corrosion on alloy CoCrFeNi2 and stainless steel 316L.

scholarly journals Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments

2013 ◽  
Vol 83 (5) ◽  
pp. 864-869 ◽  
Author(s):  
Elisa J. Kassab ◽  
José Ponciano Gomes
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Fluoride Concentration ◽  
Nickel Titanium ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Nacl Solution ◽  
Galvanic Coupling ◽  
Beta Titanium

ABSTRACT Objective: To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. Materials and Methods: NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Results: Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. Conclusions: There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

scholarly journals Effect of Structural Modification on Corrosion Behavior of Hypo Eutectic Al-Si Alloy

2018 ◽  
Vol 778 ◽  
pp. 16-21
Author(s):  
Muhammad Mansoor ◽  
Muhammad Kamran Yaseen ◽  
Shaheed Khan
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Earth Metal ◽  
Alloy System ◽  
Eutectic Phase ◽  
Al Alloy ◽  
General Corrosion ◽  
Corrosion Properties ◽  
Unmodified Alloy ◽  
Cast Alloys

Al-Si eutectic cast alloys are widely used in aeronautical and automobile industries where significantly high strength, toughness and wear resistance are required. This class of cast alloys exhibit relatively low corrosion resistance in brine environments. The mechanical properties of the alloy system mainly depend upon the shape of Si rich eutectic phase, which mainly has acicular geometry. In present research, the effect of modified microstructure of 12 wt. % Si-Al alloy on corrosion behavior was studied. The needle like Si rich eutectic phase was modified to disperse spherical structure using rare earth metal halides. The corrosion rate and pitting behavior of modified and unmodified alloy were evaluated in 3.5% NaCl solution by general corrosion for calculated time. It was observed that the corrosion rate and pitting tendency of modified alloy had been appreciably reduced as compare to unmodified alloy. The improvement of corrosion properties were the attributes of changed morphology and distribution of Si rich eutectic phase.

scholarly journals The effect of time variation on the steels corrosion rate in 0.5 M H2SO4 solution

2021 ◽  
Vol 1 (2) ◽  
pp. 49-55
Author(s):  
Afira Ainur Rosidah ◽  
Vuri Ayu Setyowati ◽  
Suheni Suheni ◽  
Rafly Rijayanto
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Time Variation ◽  
H2so4 Solution ◽  
Steel Type ◽  
Wide Range ◽  
Aisi 4140 ◽  
Aisi 1045 ◽  
Ss 304 ◽  
Corrosion Time

Previous researches have carried out studying the corrosion behavior of steels, the most frequently used steels are medium carbon steel, alloy steel, and stainless steel. This is due to their wide range of applications. So, corrosion behavior is necessary to be analyzed for every steel type because of its wide function. This study was aimed to analyze the corrosion rate, macrostructure, and the XRD results of the AISI 1045, AISI 4140, and SS 304 which represent every steel type. Then, the steels were exposed to the 0.5M H2SO4 solution with various corrosion times. The variation of the corrosion time was 48, 96, and 144 hours. The results of this study revealed that AISI 1045 showed the highest corrosion rate with the value of 183.7 mpy at 144 hours of the time variation. All specimens obtained an increase in the corrosion rate with the increase in the corrosion time. Furthermore, for the macrostructure results, AISI 1045 and AISI 4140 gave obvious rust on the surface of the specimens for all time variation. The corrosion spots appear in the time variation of 96 and 144 hours for SS 304 specimens. XRD analysis confirmed the presence of metal oxides as corrosion products.

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