scholarly journals Comparative EIS Study of AlxCoCrFeNi Alloys in Ringer’s Solution for Medical Instruments

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 928
Author(s):  
Pedro P. Socorro-Perdomo ◽  
Néstor R. Florido-Suárez ◽  
Ionelia Voiculescu ◽  
Julia C. Mirza-Rosca
Keyword(s):  
Corrosion Resistance ◽  
Passive Film ◽  
Time Constant ◽  
Equivalent Circuits ◽  
High Entropy Alloys ◽  
Impedance Spectra ◽  
High Entropy ◽  
Al Content ◽  
Medical Instruments ◽  
Very High

Depending on the properties required for the medical instruments, compared with the classical materials, the high-entropy alloys (HEAs) are a versatile option. Electrochemical Impedance Spectroscopy (EIS) measurements have been performed on AlxCoCrFeNi-type high-entropy alloys with various concentrations of Al content (x = 0.6, 0.8, and 1.0) in order to characterize their passive film and corrosion resistance at 37 °C under infectious simulated physiological conditions (Ringer´s solution acidulated with HCl) at pH = 3. The impedance spectra were obtained at different potential values between −0.7 and +0.7 V vs. SCE. Analysis of the impedance spectra was carried out by fitting different equivalent circuits to the experimental data. Two equivalent circuits, with one time constant and two time constants respectively, can be satisfactorily used for fitting the spectra: one time constant represents the characteristics of the compact passive film, and the second one is for the porous passive film. With the decreasing of Al content, the obtained EIS results are correlated with the evolution of the microhardness and microstructure, which is characterized by Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-Ray Spectroscopy (EDAX). It can be observed for all alloys that the resistance of the passive film is very high and decreases with the potential: the very high resistance of the passive film implies a high corrosion resistance, which can be assigned to the formation of the protective oxide layer and demonstrates that the analyzed alloys fulfill the prerequisites for their use as new materials for the manufacturing of medical instruments.

Influence of the Dispersion Hardening with Nanooxides on the Corrosion Resistance of High-Entropy Alloys of the Cr–Fe–Mn–Ni System in Lead Melts

2020 ◽  
Vol 55 (4) ◽  
pp. 529-535
Author(s):  
V. М. Fedirko ◽  
V. М. Voevodin ◽  
О. М. Velykodnyi ◽  
М. А. Тykhonovskyi ◽  
І. S. Kukhar ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Entropy Alloys ◽  
Dispersion Hardening ◽  
High Entropy ◽  
Lead Melts

Corrosion of Al CoCrFeNi high-entropy alloys: Al-content and potential scan-rate dependent pitting behavior

2017 ◽  
Vol 119 ◽  
pp. 33-45 ◽  
Author(s):  
Yunzhu Shi ◽  
Bin Yang ◽  
Xie Xie ◽  
Jamieson Brechtl ◽  
Karin A. Dahmen ◽  
...  
Keyword(s):  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content ◽  
Rate Dependent ◽  
Scan Rate

Cooling Rate and Size Effect on the Microstructure and Mechanical Properties of AlCoCrFeNi High Entropy Alloy

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
F. J. Wang ◽  
Y. Zhang ◽  
G. L. Chen ◽  
H. A. Davies
Keyword(s):  
Solid Solution ◽  
Atomic Ratio ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Body Centered Cubic ◽  
Mechanical Behaviors ◽  
High Entropy ◽  
Intermediate Phases ◽  
Different Diameters ◽  
Very High

High entropy alloys are usually defined as the kind of alloys with at least five principle components, each component has the equi-atomic ratio or near equi-atomic ratio, and the high entropy alloys can have very high entropy of mixing, forming simple solid solution rather than many complex intermediate phases. In this paper, the size effects on the microstructure and mechanical behaviors of a high entropy alloy of AlCoCrFeNi was studied by preparing as-cast rod samples with different diameters. The alloy independent of cast diameter samples has the same phase of body centered cubic solid solution. With decreasing casting diameter, both the strength and the plasticity are increased slightly.

scholarly journals CrMnFeCoNi high entropy alloys with carbon and nitrogen: mechanical properties, wear and corrosion resistance

2021 ◽  
Vol 3 (11) ◽  
Author(s):  
L. Chmielak ◽  
L. Mujica Roncery ◽  
P. Niederhofer ◽  
S. Weber ◽  
W. Theisen
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Austenitic Steels ◽  
High Entropy Alloys ◽  
Interstitial Free ◽  
High Entropy ◽  
Carbon And Nitrogen ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance ◽  
The Impact

AbstractThe use of interstitial elements has been a key factor for the development of different kinds of steels. However, this aspect has been little explored in the field of high entropy alloys (HEAs). In this investigation, the effect of carbon and nitrogen in a near-equiatomic CrMnFeCoNi HEA is studied, analyzing their impact on the microstructure, and mechanical properties from 77K to 673K, as well as wear, and corrosion resistance. Carbon and nitrogen are part of the FCC solid solution and contribute to the formation of precipitates. An increase in the yield and ultimate tensile strength accompanied with a decrease in the ductility are the main effects of C and N. The impact toughness of the interstitial-free material is higher than that of C and C+N alloyed systems. Compared to CrNi and CrMn austenitic steels, the wear resistance of the alloys at room temperature is rather low. The surface corrosion resistance of HEAs is comparable to austenitic steels; nevertheless HEAs are more susceptible to pitting in chloride containing solutions.

scholarly journals Influence of Molybdenum on the Microstructure, Mechanical Properties and Corrosion Resistance of Ti20Ta20Nb20(ZrHf)20−xMox (Where: x = 0, 5, 10, 15, 20) High Entropy Alloys

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 393
Author(s):  
Karsten Glowka ◽  
Maciej Zubko ◽  
Paweł Świec ◽  
Krystian Prusik ◽  
Magdalena Szklarska ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Lattice Parameters ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Two Phase ◽  
High Entropy ◽  
Matrix Microstructure ◽  
Molybdenum Addition ◽  
Mo Content ◽  
Mechanical Properties And Corrosion

The presented work was focused on investigating the influence of the (hafnium and zirconium)/molybdenum ratio on the microstructure and properties of Ti20Ta20Nb20(ZrHf)20−xMox (where: x = 0, 5, 10, 15, 20 at.%) high entropy alloys in an as-cast state. The designed chemical composition was chosen due to possible future biomedical applications. Materials were obtained from elemental powders by vacuum arc melting technique. Phase analysis revealed the presence of dual body-centered cubic phases. X-ray diffraction showed the decrease of lattice parameters of both phases with increasing molybdenum concentration up to 10% of molybdenum and further increase of lattice parameters. The presence of two-phase matrix microstructure and hafnium and zirconium precipitates was proved by scanning and transmission electron microscopy observation. Mechanical property measurements revealed decreased micro- and nanohardness and reduced Young’s modulus up to 10% of Mo content, and further increased up to 20% of molybdenum addition. Additionally, corrosion resistance measurements in Ringers’ solution confirmed the high biomedical ability of studied alloys due to the presence of stable oxide layers.

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