scholarly journals Effect of the Thermomechanical Treatment on the Corrosion of UNSM Processed Inconel 718: An Electrochemical Study

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1488
Author(s):  
Ulises Martin ◽  
Jacob Ress ◽  
David M. Bastidas
Keyword(s):  
Charge Transfer ◽  
Grain Refinement ◽  
Passive Film ◽  
Inconel 718 ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Boundary Density ◽  
Δ Phase ◽  
Corrosion Susceptibility ◽  
Refinement Effect

In this work, the influence of thermal (TT), mechanical, and thermomechanical (TMT) treatments using the ultrasonic nanocrystal surface modification (UNSM) on the corrosion protection properties of Inconel 718 was studied, correlating the changes in the electrochemical properties with the promoted microstructure. The UNSM treatment had a grain refinement effect on the top surface, reducing the grain size from 11.5 to 7.4 µm for the first 10 µm in depth. The high grain boundary density, due to the grain refinement, enabled a faster growth of the passive film. The impedance showed a decrease in the charge transfer resistance by three orders of magnitude, from 106 to 103 Ω cm2 for as-received to 1000 °C, as the TT temperature crossed the solvus of the γ′/γ″ and approached the solvus of the δ-phase. The UNSM treatment lowered the pitting corrosion susceptibility, increasing the charge transfer resistance and decreasing the effective capacitance of the double layer, leading to the thickest passive film with 6.8 nm.

scholarly journals Effect of nanostructured carbon coatings on the electrochemical performance of Li1.4Ni0.5Mn0.5O2+ x -based cathode materials

2016 ◽  
Vol 7 ◽  
pp. 1960-1970 ◽  
Author(s):  
Konstantin A Kurilenko ◽  
Oleg A Shlyakhtin ◽  
Oleg A Brylev ◽  
Dmitry I Petukhov ◽  
Alexey V Garshev
Keyword(s):  
Diffusion Coefficient ◽  
Charge Transfer ◽  
Specific Capacity ◽  
Charge Transfer Resistance ◽  
Poly Vinyl Alcohol ◽  
Nanostructured Carbon ◽  
Transfer Resistance ◽  
Carbon Coatings ◽  
Lithium Diffusion Coefficient ◽  
Electrochemical Cycling

Nanocomposites of Li1.4Ni0.5Mn0.5O2+ x and amorphous carbon were obtained by the pyrolysis of linear and cross-linked poly(vinyl alcohol) (PVA) in presence of Li1.4Ni0.5Mn0.5O2+ x . In the case of linear PVA, the formation of nanostructured carbon coatings on Li1.4Ni0.5Mn0.5O2+ x particles is observed, while for cross-linked PVA islands of mesoporous carbon are located on the boundaries of Li1.4Ni0.5Mn0.5O2+ x particles. The presence of the carbon framework leads to a decrease of the polarization upon cycling and of the charge transfer resistance and to an increase in the apparent Li+ diffusion coefficient from 10−16 cm2·s−1 (pure Li1.4Ni0.5Mn0.5O2+ x ) to 10−13 cm2·s−1. The nanosized carbon coatings also reduce the deep electrochemical degradation of Li1.4Ni0.5Mn0.5O2+ x during electrochemical cycling. The nanocomposite obtained by the pyrolysis of linear PVA demonstrates higher values of the apparent lithium diffusion coefficient, a higher specific capacity and lower values of charge transfer resistance, which can be related to the more uniform carbon coatings and to the significant content of sp2-hybridized carbon detected by XPS and by Raman spectroscopy.

Estimation of continuity of electroactive inorganic films based on apparent anti-Ohmic trend in their charge transfer resistance

2016 ◽  
Vol 219 ◽  
pp. 588-591 ◽  
Author(s):  
Maria A. Komkova ◽  
Elena V. Karpova ◽  
Grigory A. Sukhorukov ◽  
Alexey A. Sadovnikov ◽  
Arkady A. Karyakin
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Inorganic Films

Reduction of Charge-Transfer Resistance via Artificial SEI Formation Using Electropolymerization of Borylated Thiophene Monomer on Graphite Anodes

2018 ◽  
Vol 165 (3) ◽  
pp. A493-A500 ◽  
Author(s):  
Prerna Joshi ◽  
Katsuhito Iwai ◽  
Sai Gourang Patnaik ◽  
Raman Vedarajan ◽  
Noriyoshi Matsumi
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Graphite Anodes

Cobalt oxide enhanced lanthanum strontium cobalt ferrite electrode for solid oxide fuel cells

2021 ◽  
pp. 1-13
Author(s):  
Alberto Olivo ◽  
Berceste Beyribey ◽  
Hwan Kim ◽  
Joshua Persky
Keyword(s):  
Charge Transfer ◽  
Solid Oxide Fuel Cells ◽  
Charge Transfer Resistance ◽  
Solid Oxide ◽  
Co3o4 Nanoparticles ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Oxide Fuel ◽  
Transfer Resistance ◽  
And Diffusion

A Co3O4 enhanced La0.8Sr0.2Co0.5Fe0.5O3 - δ (LSCF) electrode is developed for use in air electrodes with proton conducting solid oxide fuel cell (SOFC). The incipient wetness impregnation method enables Co3O4 nanoparticles on the LSCF surface without altering the bulk porosity of the LSCF electrode. The polarization resistance of LSCF electrodes is significantly reduced by Co3O4 doping, and both charge transfer and diffusion/conversion resistances were positively affected. The highest reduction in charge transfer resistance is obtained at 700 °C, which is increased from 21%to 32%through reduction of po 2. Conversely, the highest reduction in diffusion/conversion resistance is achieved at 550 °C. By increasing po 2, the reduction is increased from 57%to 66%and its activation energy is reduced up to 33 %compared to pure LSCF. The lowest total area specific resistances obtained under air are 1.45 Ω·cm2, 2.95 Ω·cm2, 6.75 Ω·cm2 and 16.45 Ω·cm2 at 700 °C, 650 °C, 600 °C and 550 °C, respectively.

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