Corrosion Studies of Sintered Cobalt-Based Alloys in Sodium Chloride

2021 ◽  
Vol 107 ◽  
pp. 144-148
Author(s):  
Feyisayo Victoria Adams ◽  
Reneilwe Agrieneth Moloto ◽  
Samuel Olukayode Akinwamide ◽  
Peter Apata Olubambi
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Nacl Solution ◽  
Medical Field ◽  
Sem Images ◽  
Electrochemical Tests ◽  
Cr Content ◽  
Corrosion Studies ◽  
Before And After ◽  
Ti Addition

Cobalt-based alloys have recently gained so much attention in the medical field due to their improved mechanical properties such as wear resistance and high thermal stability. However, limitations in the area of corrosion has posed a great challenge, leading to further studies being carried out on the corrosion resistance of these alloys. In this study, an investigation on the corrosion resistance of Co-Cr-Mo based alloys in 0.9 % NaCl solution was carried at 37 oC and pH of 7.4 using potentiodynamic polarization and chronopotentiometry electrochemical techniques. The surface analysis of the alloys before and after corrosion test was done using scanning electron microscope (SEM). The results obtained from the electrochemical tests showed sample without titanium (Ti) addition to be more resistance to corrosion in the salt solution compared to those containing Ti. It was observed that a decrease in Cr content in the alloys resulted in an increase in corrosion rate from 0.7868 to 1.3805 mpy. The SEM images confirmed the presence of Cr, Co and Mo in the alloys.

scholarly journals Microstructure and Corrosion Properties of La2Zr2O7/NiCoAlY Thermal Barrier Coatings Deposited on Inconel 718 Superalloy by Laser Cladding

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Kaijin Huang ◽  
Wei Li ◽  
Kai Pan ◽  
Xin Lin ◽  
Aihua Wang
Keyword(s):  
Corrosion Resistance ◽  
Thermal Barrier Coating ◽  
Laser Cladding ◽  
Inconel 718 ◽  
Electrochemical Techniques ◽  
Thermal Barrier ◽  
Nacl Solution ◽  
Corrosion Performance ◽  
Barrier Coating ◽  
Inconel 718 Superalloy

In order to improve the seawater corrosion resistance of Inconel 718 superalloy, a La2Zr2O7/NiCoCrAlY thermal barrier coating corrosion resistant to 3.5 wt.% NaCl aqueous solution was prepared by laser cladding on Inconel 718 superalloy. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and electrochemical techniques were used to study the microstructure and the corrosion performance of the coating in 3.5 wt.% NaCl solution. The results show that the thermal barrier coating is mainly composed of primary La2Zr2O7 phase and γ + laves/δ phase eutectic structure. The corrosion potential and corrosion current of the coating in 3.5 wt.% NaCl solution are higher and lower than that of the Inconel 718 substrate, respectively, indicating that the corrosion performance of the coating is better than that of the Inconel 718 substrate. The presence of La2Zr2O7 phase in the thermal barrier coating is the main reason for its corrosion resistance to 3.5 wt.% NaCl solution.

scholarly journals The role of chromium content in the long-term atmospheric corrosion process

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Baozhuang Sun ◽  
Xiaomei Zuo ◽  
Xuequn Cheng ◽  
Xiaogang Li
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Atmospheric Corrosion ◽  
X Ray Diffraction ◽  
Kelvin Probe ◽  
Electrochemical Tests ◽  
Force Microscopy ◽  
Cr Content ◽  
Alloy Steels ◽  
Bare Steel

AbstractThe corrosion of alloy steels with different amounts of Cr was studied using electrochemical tests, wet–dry cycle corrosion, X-ray diffraction, and Kelvin probe force microscopy. The results show that the content of Cr is positively correlated with the corrosion resistance of bare steel, but the corrosion resistance of atmospheric corrosion does not show the same pattern. The atmospheric corrosion resistance of Cr-containing steel exhibits three different stages with the change of Cr element content. When the Cr content is in the range of 1–4%, the corrosion rate is high and does not change within the Cr content. As the Cr content was further increased from 4 to 7%, the corrosion rate exhibited a linear decrease and then drops rapidly when the Cr content reaches 8%. These three different corrosion rate stages are related to the influence of Cr content on Fe3O4 content in the rust layer.

Fabrication of Hydrophobic Surfaces and its Electrochemical Research on Copronickel B30

2011 ◽  
Vol 347-353 ◽  
pp. 560-563 ◽  
Author(s):  
Qun Jie Xu ◽  
Xi Hong Cai ◽  
Hong Yun ◽  
Xian Qin Deng
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Stearic Acid ◽  
Inhibition Efficiency ◽  
Electrochemical Techniques ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Nacl Solution ◽  
Film Properties ◽  
Water Contact

A novel hydrophobic film was prepared by Stearic acid (SA) chemically adsorbed onto the cupronickel B30 surface. The film properties were characterized by means of water contact angle measurement and electrochemical techniques. The results indicate that the structure of the adsorbed film is hydrophobic, and the contact angle is 113.82° for water. AC impedance and polarization curve measurements show that the corrosion resistance of cupronickel B30 modified by stearic acid is improved remarkably, and the inhibition efficiency reached 66.85%. After hydrophobic modified by stearic acid, the inhibition efficiency could reach 88.85% in 3% NaCl solution with the concentration of 0.1 g/L Na2WO4.

scholarly journals Corrosion Resistance of Co-Cr-Mo Alloy Used in Dentistry

2015 ◽  
Vol 60 (1) ◽  
pp. 523-528 ◽  
Author(s):  
A. Łukaszczyk ◽  
J. Augustyn-PieniąŻek
Keyword(s):  
Corrosion Resistance ◽  
Artificial Saliva ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Electrochemical Studies ◽  
Brand Name ◽  
Dental Alloys ◽  
Casting Method ◽  
Electrochemical Tests ◽  
Dental Technician

Abstract The presented paper studies the effect of the casting technology on the corrosion resistance of Co-Cr-Mo alloy. The investigations were conducted on a commercial alloy with the brand name ARGELOY N.P SPECIAL (Co-Cr-Mo) produced by Argen as well as the same alloy melted and cast by the lost wax casting method performed by a dental technician. The corrosion behavior of the dental alloys in an artificial saliva was studied with the use of the following electrochemical techniques: open circuit potential and voltammetry. After the electrochemical tests, studies of the surface of the examined alloys were performed by means of a scanning electron microscope with an X-ray microanalyzer. The results of the electrochemical studies show that the dependence of the corrosion resistance on the microstructure associated with the recasting process is marginal. The results of the electrochemical studies of the considered alloy clearly point to their good corrosion resistance in the discussed environment.

scholarly journals Effect of Sr and Ti Addition on the Corrosion Behaviour of Al-7Si-0.3Mg Alloy

2017 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
M. Uludağ ◽  
M. Kocabaş ◽  
D. Dışpınar ◽  
R. Çetin ◽  
N. Cansever
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Potentiodynamic Polarization ◽  
Corrosion Test ◽  
Corrosion Behaviour ◽  
Tensile Tests ◽  
Nacl Solution ◽  
Cyclic Potentiodynamic Polarization ◽  
Ti Addition

AbstractIn the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3mm/year). However, additive elements do not show the effect which degassing process shows.

Effect of Chromium Addition on Damping Capacity, Mechanical Property, and Corrosion Resistance of Fe-18%Mn Alloy

2006 ◽  
Vol 319 ◽  
pp. 73-78 ◽  
Author(s):  
Jung Chul Kim ◽  
Seung Han Baik ◽  
Joong Hwan Jun ◽  
Young Kook Lee
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Immersion Test ◽  
Damping Capacity ◽  
Nacl Solution ◽  
Chromium Addition ◽  
Cr Content ◽  
Cr Addition ◽  
Start Temperature

Effect of Cr addition on damping capacity, mechanical property, and corrosion resistance of Fe-18%Mn martensitic alloy has been studied. Martensite start temperature (Ms) of the alloy decreases linearly from 150 to 25 with increasing Cr content up to 15%. The damping capacity decreases gradually from 27 to 23% in SDC with increasing Cr content from zero to 10%, and decreases rapidly with further Cr content. The tensile strength of the alloy maintains a level of 60 / regardless of Cr content with an elongation of 20 to 25%. Immersion test in 5% NaCl solution leads to the result that the corrosion resistance of the alloy becomes excellent above 10% Cr. From the above results, it is concluded that the optimum Cr content to improve the mechanical property and corrosion resistance of the alloy with a lesser decrease in damping capacity is about 10%.

Comparative Study of Microstructural and Corrosion Characteristics of Excimer Laser-Melted AA2124-T4 and AA6061-T4 Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 235-240 ◽  
Author(s):  
Dai Shu Qian ◽  
Zhu Liu
Keyword(s):  
Corrosion Resistance ◽  
Excimer Laser ◽  
Corrosion Behaviour ◽  
Electrochemical Techniques ◽  
Compositional Analysis ◽  
Laser Pulses ◽  
Immersion Test ◽  
Nacl Solution ◽  
Intermetallic Particles ◽  
Melted Layer

A KrF excimer laser was introduced for laser surface melting (LSM) of the aluminium alloys AA2124-T4 and AA6061-T4. The microstructural and compositional analysis was conducted using SEM, low-angle XRD, and TEM; the corrosion behaviour of as-received (AR) and laser-treated (LT) samples was evaluated by electrochemical techniques and immersion test in a 3.5% NaCl solution. A melted layer consisting of a re-solidified layer with refined microstructure and dissolution of intermetallic particles (IMPs), and a thin film of aluminium oxides at the top, was formed after LSM for both alloys. The corrosion resistance of both alloys was improved after LSM. The results of immersion test showed different corrosion behaviour for LT AA2124 and LT AA6061. The delamination of the melted layer was observed for AA2124 but was not observed for AA6061 after exposure to 3.5% NaCl solution for 24 h. This was attributed to the formation of copper-rich segregation bands in the melted layer of AA2124 due to higher content of copper in AA2124 than AA6061. A significant number of micro-pores were present in the melted layer for AA2124 treated with high number of laser pulses, leading to the decrease of the corrosion resistance.

The Application of Electrochemical Techniques to the Study of Corrosion of Automotive Trim Materials

CORROSION ◽  
1969 ◽  
Vol 25 (2) ◽  
pp. 47-58 ◽  
Author(s):  
M. S. WALKER ◽  
L. C. ROWE
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
Electrochemical Techniques ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Field Exposure ◽  
Electrochemical Tests ◽  
Potentiodynamic Anodic Polarization ◽  
Pit Initiation ◽  
Mechanisms Of Reactions

Abstract De-icing salts are known to have a contributing effect on the corrosion of automotive trim materials. Various accelerated tests have been developed to evaluate the corrosion resistance of trim materials, but each test has its own limitations. Electrochemical techniques are a valuable supplement to these other methods, not only because they are fast and reproducible but also because they help in determining mechanisms of reactions. A potentiodynamic anodic polarization method was used to show the relative corrosion resistance of four different stainless steels and a chromium plated stainless steel used in trim applications, and the order of corrosion resistance compared favorably with that obtained by conventional chemical tests and by field exposure. Furthermore, the test was used to show distinct differences in the pitting susceptibility of stainless steels exposed to different concentrations of chloride ion. The thermographic test is commonly used to evaluate the corrosion resistance of stainless steels. The effect of specific ingredients in the solution on corrosion was determined by both chemical and electrochemical tests. Chemical tests showed that chloride and thiosulfate ions had the greatest effect on pit initiation, probably because the thiosulfate altered the redox potential of the solution. Potentiodynamic polarization measurements indicated that the chloride ion concentration was rate controlling after corrosion had begun, and the thiosulfate ion caused a shift in potential which placed the material in a corroding region.

Structure and Anti-Corrosion of Tri-Layer Ni-P Amorphous Alloy Coating Prepared in the Same Bath

2007 ◽  
Vol 546-549 ◽  
pp. 1805-1808
Author(s):  
Li Qun Zhu ◽  
Yan Bin Du ◽  
Zhen Xue ◽  
Ying Xu Li
Keyword(s):  
Corrosion Resistance ◽  
Alloy Coating ◽  
Amorphous Coating ◽  
Nacl Solution ◽  
Excellent Performance ◽  
Electrochemical Protection ◽  
Heat Treated ◽  
Before And After ◽  
Layer Coating

A tri-layer amorphous Ni-P alloy coating was prepared in the same bath by changing the temperatures and currents, followed by heat treament. We studied the behavior of corrosion-resistance of the tri-layer coating before and after heat-treatment at 360°C for different time in the 5% NaCl solution. The result showed that: the tri-layer amorphous Ni-P coating has the excellent performance of anti-corrosion compare with single electroless or electrodeposited Ni-P amorphous coating. The performance of anti-corrosion of the coating was improved by controlling the coating’s structure and the role of electrochemical protection. After being heat-treated at 360°C for 1 hour ,the coating’s structure changed from amorphous to crystalloid and the corrosion resistance of the heat-treated coatings was higher than as-plated tri-layer Ni-P coating.

Effect of Surface Treatment by DCPD Coating on Corrosion Resistance of Magnesium Alloy Elektron 21

2014 ◽  
Vol 811 ◽  
pp. 67-73
Author(s):  
Miroslav Omasta ◽  
Branislav Hadzima ◽  
Filip Pastorek
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Water Solution ◽  
Ground Surface ◽  
Nacl Solution ◽  
Electrodeposition Process ◽  
Electrochemical Tests ◽  
Effect Of Surface

Electrodeposition process of calcium phosphate (CaP) was performed on Elektron 21 magnesium alloy and the influence on corrosion resistance of the alloy covered by CaP was investigated by electrochemical tests. The electrodeposition treatment was performed by potential controlled method in water solution of Ca (NO3)2.4H2O, NH4H2PO4 and H2O2. Corrosion measurements were performed in 0.1M NaCl solution at laboratory temperature (22 ± 1 °C) using electrochemical impedance spectroscopy. Electrodeposited surfaces had higher polarization resistance than only ground surface after all exposition time in 0.1M NaCl.

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