Corrosion Behavior of Amorphous Co69Fe4.5Cr1.5Si10B15 Alloy

CORROSION ◽  
2010 ◽  
Vol 66 (11) ◽  
pp. 116002-116002-4 ◽  
Author(s):  
H.-G. Kim ◽  
H. J. Jang

Abstract The corrosion behavior of amorphous Co69Fe4.5Cr1.5Si10B15 alloy ribbon was investigated using potentiodynamic polarization tests in 0.001 M sulfuric acid (H2SO4) solution, 0.01 M ∼ 0.09 M sodium chloride (NaCl) solution, and solutions at pH levels from 3 to 13 made by mixing hydrochloric acid (HCl) and sodium hydroxide (NaOH). The corrosion potential decreased and the corrosion rate increased with an increase in solution temperature. The influence of solution temperature was more significant in H2SO4 solution than in NaCl solution. The amorphous Co69Fe4.5Cr1.5Si10B15 alloy ribbon showed passivity in solution with a pH higher than 7, and the corrosion rate was minimized at a pH of 9.

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 377 ◽  
Author(s):  
Yeong-Ho Son ◽  
Soon-Hyeok Jeon ◽  
Geun Song ◽  
Jong Lee ◽  
Do Hur

The effects of magnetite on the corrosion behavior of SA508 were studied in 10% and 20% EDTA-based chemical cleaning solutions at 93 °C and 121 °C using electrochemical and immersion tests. SA508 was the anode of the galvanic pair between SA508 and magnetite. The galvanic coupling shifted the mixed corrosion potential of SA508 in the positive direction and thus increased its corrosion rate. The increase of the EDTA concentration and solution temperature led to an increase in the extent of the galvanic effect.


Author(s):  
J. Hrabia-Wiśnios ◽  
B. Leszczyńska-Madej ◽  
R. Kowalik

Purpose: The results presented the microstructure and corrosive behavior of SnSb12Cu6Pb alloy (B82) in H2SO4 aqueous solution and NaCl aqueous solution. Design/methodology/approach: The electrochemical corrosion has been investigated in two different aqueous solutions: 0.1M sulfuric acid (H2SO4) and 0.5M sodium chloride (NaCl) solution measuring of potential changes relative to immersion time and conducting mass loss test. Microscopic investigations before and after corrosion tests were made using scanning electron microscopy. Findings: The obtained results indicate very good corrosion resistance of the alloy tested in NaCl solution. Corrosion progresses faster in a sulfuric acid aqueous solution compared to sodium chloride aqueous solution. Also, it was found that the dominant mechanism of corrosion degradation in both solutions is selective corrosion which is a particularly undesirable type of corrosion because it involves the loss of one alloying component and the formation of porous structure on the alloy surface. Research limitations/implications: The aqueous solutions used in this study are not a natural working environment of the bearing. However, a comparison of acidic and neutral solutions allows explaining the corrosion behavior of tin babbitts due to contaminants of oil lubricants. Further research should be conducted in more aggressive environments characteristic of industrial conditions. Practical implications: One of the important properties of bearing alloys are corrosion resistance. Corrosion properties are extremely important for the transport and storage of metallic components before they are used. Also, the working environment can have a destructive effect on the properties of the materials used. Industry environment, aging stagnant oil, and some acids may lead to selective corrosion of the tin, copper, lead, or antimony components and leaving a rough and weakened the babbitt surface. Electrochemical corrosion can contribute to the acceleration of bearing wear and consequent to bearing damage. Originality/value: Studies of the corrosion of tin-babbitt bearings are not extensive in the literature due to rare tin corrosion. This study could be an important complement to knowledge about the corrosion behavior of tin-based bearing alloys.


2013 ◽  
Vol 14 (1) ◽  
pp. 103-108
Author(s):  
Jagadeesh Bhattarai ◽  
Susil Baral

The corrosion behavior of the sputter–deposited amorphous and nanocrystalline W–xTa (x = 8–77) alloys was studied in 0.5 M NaCl solution open to air at 25°C using corrosion tests and electrochemical measurements. Tungsten and tantalum metals act synergistically in enhancing the corrosion resistance of the sputter–deposited W–xTa alloys and hence additions of 23 at. % of tantalum or more to the sputter–deposited W–xTa alloys were found to be effective to achieve significantly high corrosion resistance properties of the alloys than those of alloy– constituting elements. In particular, the corrosion rate of the W–60Ta alloy showed the lowest corrosion rate (that is, 2.0×10-3). The open circuit potential of the alloys shifted noble (positive) direction with immersion time. Addition of tantalum metal in W–xTa alloys is effective for ennoblement of the open circuit corrosion potential of the tungsten metal in 0.5 M NaCl solution open to air at 25°C. Nepal Journal of Science and Technology Vol. 14, No. 1 (2013) 103-108 DOI: http://dx.doi.org/10.3126/njst.v14i1.8929


2021 ◽  
Vol 2 (1) ◽  
pp. 61-77
Author(s):  
Hamid Reza Jafari ◽  
Ali Davoodi ◽  
Saman Hosseinpour

In this work, the corrosion behavior and surface reactivity of as-cast and heat-treated nickel aluminum bronze casting alloy (UNS C95800) in 3.5 wt% NaCl solution is investigated under stagnant and flow conditions. Increasing flow rate conditions are simulated using a rotating disk electrode from 0 to 9000 revolutions per minute (rpm). Optical micrographs confirm the decrease in the phase fraction of corrosion-sensitive β phase in the microstructure of C95800 after annealing, which, in turn, enhances the corrosion resistance of the alloy. Electrochemical studies including open circuit potentiometry, potentiodynamic polarization, and electrochemical impedance spectroscopy are performed to assess the effect of flow rate and heat treatment on the corrosion of samples at 25 and 40 °C in 3.5 wt% NaCl solution. For both as-cast and heat-treated samples, increasing the flow rate (i.e., electrode rotating rate) linearly reduces the corrosion resistance, indicating that the metal dissolution rate is significantly affected by hydrodynamic flow. Increasing the solution temperature negatively impacts the corrosion behavior of the as-cast and heat-treated samples at all flow conditions.


Author(s):  
Afira Ainur Rosidah ◽  
Vuri Ayu Setyowati ◽  
Suheni Suheni ◽  
Rafly Rijayanto

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.


CORROSION ◽  
1981 ◽  
Vol 37 (7) ◽  
pp. 392-407 ◽  
Author(s):  
C. A. C. Sequeira ◽  
M. G. Hocking

Abstract The corrosion behavior of Nimonic 105 in molten Na2SO4, NaCl, and mixtures of these two salts, at 900 C, in laboratory air and under O2 + SO2/SO3 atmospheres has been evaluated by potentiodynamic, potential decay, and free corrosion potential measurements. In addition, the corrosion products were examined using several electron-optical techniques, and by other analytical methods. Pure Na2SO4 in air did not seem to be very corrosive towards Nimonic 105. Addition of NaCl to the molten Na2SO4 resulted in increased dissolution of Nimonic 105, which was in general nonuniform, alloy constituents nickel and cobalt dissolving more than others. Evidence of internal attack and enhancement of dissolution of the Ni alloy by SO3 was significant only when the corrosion conditions were prolonged. In pure NaCl, catastrophic corrosion occurs, which has been attributed to the depletion, dissolution, and vaporization of some alloy species.


1970 ◽  
Vol 25 ◽  
pp. 53-61
Author(s):  
Minu Basnet ◽  
Jagadeesh Bhattarai

The corrosion behavior of the sputter-deposited nanocrystalline W-Cr alloys wasstudied in 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open to air usingimmersion tests and electrochemical measurements. Chromium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Cr alloys soas to show higher corrosion resistance than those of alloy-constituting elements in both 0.5M NaCl and 1 M NaOH solutions. In particular, the nanocrystalline W-Cr alloys containing25-91 at% chromium showed about one order of magnitude lower corrosion rates (that is,about 1-2 × 10-3 mm.y-1) than those of tungsten and chromium metals even for prolongedimmersion in 0.5 M NaCl solution at 25°C. On the other hand, the corrosion rate of thesputter-deposited W-Cr alloys containing 25-75 at % chromium was decreased significantlywith increasing chromium content and showed lowest corrosion rates (that is, 1.5-2.0 × 10-3 mm.y-1) after immersed for prolonged immersion in 1 M NaOH solution. The corrosion ratesof these nanocrystalline W-(25-75)Cr alloys are nearly two orders of magnitude lower thanthat of tungsten and more than one order of magnitude lower corrosion rate than that ofsputter-deposited chromium metal in 1 M NaOH solution. The corrosion-resistant of all theexamined sputter-deposited W-Cr alloys in 0.5 M NaCl solution is higher than in alkaline 1M NaOH solution at 25°C. Open circuit potentials of all the examined W-Cr alloys areshifted to more noble direction with increasing the chromium content in the alloys afterimmersion for 72 h in both 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air.Keywords: Sputter deposition, nanocrystalline W-Cr alloys, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI:  10.3126/jncs.v25i0.3300Journal of Nepal Chemical Society Volume 25, 2010 pp 53-61


2009 ◽  
Vol 620-622 ◽  
pp. 153-156 ◽  
Author(s):  
Kyung Chul Park ◽  
Byung Ho Kim ◽  
Jong Jin Jeon ◽  
Yong Ho Park ◽  
Ik Min Park

In the present work, the effect of Sn addition on the corrosion behavior of Mg–5Al–1Zn alloys was investigated. Microstructure, potentiodynamic polarization and immersion tests were carried out in 3.5% NaCl solution of pH 7.2 to estimate the corrosion behavior of AZ51 alloys with and without Sn addition. Mg17Al12 and Mg2Sn phases were mainly precipitated in inter-dendrite structures. With increasing the Sn content, the volume fraction of the Mg2Sn phase was increased and coarsening tendency was observed. The corrosion resistance was increased by Sn addition. Especially, the AZ51-5wt.%Sn alloy characterized the superior corrosion resistance among the four alloys. The Sn is known for a high hydrogen overvoltage and the secondary phases effectively formed the network structure, resulting in a drastically decreasing corrosion rate of AZ51 alloy.


2014 ◽  
Vol 893 ◽  
pp. 440-443
Author(s):  
Li Na Zhang ◽  
Jerzy A. Szpunar ◽  
Jian Xin Dong ◽  
Mai Cang Zhang

The influence of ions chloride concentration and pH value on the corrosion resistance of high-alloyed material UNS N08028 in the sodium chloride solution is investigated. Results show that the corrosion potential is active cathodically with the increase of chloride concentration. The current density and corrosion rate both increase with increasing chloride concentration and decreasing pH value.


2019 ◽  
Vol 26 (3) ◽  
pp. 219-225
Author(s):  
Robert Starosta

Abstract Due to the paramagnetic properties and the ability to passivation, for the production of hulls of some vessels (mainly warships), corrosion-resistant (stainless) steels with austenitic structure are used. This article describes the influence of seawater salinity on selected corrosion properties of high-alloy steel X5CrNi 18-10 (304). The average salinity of the seas is taken as 3.5% content of sodium chloride. Corrosion rate of the tested material was evaluated in an aqueous solution of sodium chloride was evaluated. The NaCl concentration in corrosive solutions was 0.7%, 1.4%, 2.1%, 2.8%, 3.5%, 4.2%. Corrosion tests were performed using the potentiodynamic method. The range of electrochemical potential changes was Ecorr ±150 mV. Corrosion rate was assessed on the basis of corrosion current density measurements. Corrosion potential values against the saturated calomel electrode were also determined. Based on the obtained measurement results and non-parametric significance tests carried out, a significant influence of seawater salinity on the value of corrosion current density and corrosion potential was found. The highest value of corrosion current density (jcorr), and thus the highest corrosion rate, was recorded for 3.5% NaCl solution. In the concentration range from 0.7 to 3.5% NaCl in solution, the corrosion rate of austenitic steel increases. A further increase in salinity of electrolyte results in the inhibition of corrosion rate of steel. There is almost a full negative, linear correlation between the proportion of sodium chloride in the corrosive solution and the value of corrosion potential. Along with the rise in the salinity of seawater, increase the electrochemical activity, and thus the corrosion susceptibility, thus the corrosion susceptibility, of the austenitic steel X5CrNi 18-10 was observed.


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