scholarly journals Corrosion of WC-VC-Co Hardmetal in Neutral Chloride Containing Media

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
C. N. Machio ◽  
D. S. Konadu ◽  
J. H. Potgieter ◽  
S. Potgieter-Vermaak ◽  
J. Van der Merwe
Keyword(s):  
Corrosion Resistance ◽  
Sodium Chloride ◽  
Chemical Composition ◽  
Corrosion Behavior ◽  
Mine Water ◽  
Analytical Methods ◽  
Anodic Polarization ◽  
Polarization Behavior

The effect of varying VC content on the corrosion behavior of WC-10 wt% Co hardmetals in sodium chloride (NaCl) and synthetic mine water (SMW) solutions has been investigated using anodic polarization scans and surface analytical methods. It is shown that the polarization behavior is active-pseudopassive in NaCl and active in SMW regardless of the VC content, while the corrosion resistance is poorer and independent of VC content in NaCl but better at high VC contents in SMW. The corrosion behavior of samples is explained using the effect of VC on the chemical composition of the binder.

Hot Corrosion of Nimonic 105 in Sodium Sulfate-Sodium Chloride Melts

CORROSION ◽  
1981 ◽  
Vol 37 (7) ◽  
pp. 392-407 ◽  
Author(s):  
C. A. C. Sequeira ◽  
M. G. Hocking
Keyword(s):  
Sodium Chloride ◽  
Corrosion Behavior ◽  
Analytical Methods ◽  
Sodium Sulfate ◽  
Hot Corrosion ◽  
Corrosion Potential ◽  
Free Corrosion Potential ◽  
Chloride Melts ◽  
Ni Alloy ◽  
Potential Decay

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.

Corrosion Resistance Evaluation of a Stainless-Steel Brazed Joint in HCl Solution

2021 ◽  
Vol 1016 ◽  
pp. 997-1002
Author(s):  
Hikaru Nagata ◽  
Masa Ono ◽  
Yasuyuki Miyazawa ◽  
Yuji Hayashi ◽  
Yoshio Bizen
Keyword(s):  
Aqueous Solution ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Base Metal ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Filler Metal ◽  
Brazed Joint ◽  
In Situ Observations

To clarify the effect of the acid solution type on corrosion resistance, the corrosion behavior of stainless steel brazed joints in HCl aqueous solution was evaluated through electrochemical measurements. Anodic polarization curves of a ferritic stainless-steel base metal, Ni-based brazing filler metals, and a brazed joint were recorded. In addition, in situ observations were conducted to observe the corrosion behavior of each structure of the brazed joint. Corrosion potentials of the brazing filler metal were lower than that of the base metal. In situ observations of the brazed joint revealed the order of corrosion in aqueous hydrochloric acid. According to the electrochemical measurements, under an actual corrosive environment, the brazing filler metal can function as an anode and selectively corrode. In addition, the anodic polarization curve of the brazed joint showed values between those of the polarization curves of the brazing filler metal and the base metal, indicating that the corrosion resistance could be electrochemically evaluated in HCl aqueous solution.

scholarly journals The influence of sodium chlorides fog on corrosion resistance of heat exchangers used in automotive

2017 ◽  
Vol 37 (1) ◽  
pp. 45-49
Author(s):  
Katarzyna Peta ◽  
Karol Grochalski ◽  
Adam Piasecki ◽  
Jan Żurek
Keyword(s):  
Corrosion Resistance ◽  
Heat Exchanger ◽  
Sodium Chloride ◽  
Chemical Composition ◽  
Light Microscopy ◽  
Heat Exchangers ◽  
Winter Season ◽  
Road Maintenance ◽  
Critical Areas ◽  
Corrosion Pits

AbstractIn the work, the most important factors which influence on the exploitative durability of heat exchangers are classified. Particular attention was paid to the compounds of sodium chloride used in the winter season for road maintenance. In order to determine their impact on automotive heat exchanger corrosion resistance, a test of heaters in a salt chamber which imitates the conditions of their work was realized. It also allows to verify the durability of these products. To evaluate the corrosion changes, observation with the use of light microscopy and scanning microscopy SEM were made supplemented with microanalysis of chemical composition by EDS spectroscopy method. Critical areas in the heat exchangers which are mostly exposed to damage including the formation of local corrosion pits were located and analyzed.

scholarly journals Corrosion Behavior of CoCrFeNiTax Alloys in 1 M Sodium Chloride Aqueous Solution

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5157
Author(s):  
Chun-Huei Tsau ◽  
Rong-Wei Hsiao ◽  
Tien-Yu Chien
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Sodium Chloride ◽  
Corrosion Behavior ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Electrochemical Impedance ◽  
Eutectic Structure ◽  
Different Temperatures

This paper investigates the effects of Ta content on the microstructures, hardness and corrosion behavior of as-cast CoCrFeNiTax alloys. The results indicate that the addition of Ta can change the microstructures of these alloys to dual-phased structures (FCC + HCP), as well as increasing their hardness. This study uses constant galvanostatic/potentiometric methods to measure the polarization curves of CoCrFeNiTa0.1, CoCrFeNiTa0.3 and CoCrFeNiTa0.5 alloys in deaerated 1 M sodium chloride solution at different temperatures. Electrochemical impedance spectroscopy is also used to analyze these alloys in sodium chloride solution. The results indicate that the CoCrFeNiTa0.5 alloy has a eutectic structure and the highest hardness. Furthermore, although the CoCrFeNiTa0.5 alloy has the best corrosion resistance, the CoCrFeNiTa0.3 alloy has the best pitting resistance among these alloys.

Anodic Polarization of Anodized Aluminum

CORROSION ◽  
1969 ◽  
Vol 25 (4) ◽  
pp. 187-192 ◽  
Author(s):  
D. A. JONES
Keyword(s):  
Corrosion Resistance ◽  
Coating Thickness ◽  
Anodic Polarization ◽  
Atmospheric Corrosion ◽  
Anodized Aluminum ◽  
Polarization Behavior ◽  
Polarization Test

Abstract Potentiostatic anodic polarization of anodized coatings on aluminum was sensitive to both coating thickness and degree of seal. The polarization behavior of anodized coatings parallels their performance in atmospheric service. Thus, anodic polarization could be used as a test for the atmospheric corrosion resistance of anodized coatings. The advantages of an anodic polarization test are discussed.

Investigations of corrosion behaviour of SnSb12Cu6Pb alloy in 0.1M H2SO4 and 0.5M NaCl solution

2020 ◽  
Vol 1 (101) ◽  
pp. 5-14
Author(s):  
J. Hrabia-Wiśnios ◽  
B. Leszczyńska-Madej ◽  
R. Kowalik
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Sodium Chloride ◽  
Aqueous Solutions ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Working Environment ◽  
Nacl Solution ◽  
Selective Corrosion

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.

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