scholarly journals A Novel Self-Healing Conversion Film Formed on Rebar in Solution Containing Cerium and Molybdenum Ions

2021 ◽  
Author(s):  
Hongze An ◽  
Donatien NGENDABANYIKWA ◽  
Guozhe Meng ◽  
Wang Yanqiu ◽  
Wang Junyi ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Charge Transfer ◽  
Outer Layer ◽  
Layer Structure ◽  
Charge Transfer Resistance ◽  
Self Healing ◽  
Transfer Resistance ◽  
Pitting Potential ◽  
Alkaline Environment

Abstract A novel conversion film containing cerium and molybdenum was synthesized on the rebar surface, and then the pitting sensitivity of the rebar was improved in a concrete environment containing chloride. This conversion film presented a two-layer structure, which involved CeMoOx as the outer layer and FeOx as the inner layer. The film with two-layer structure exhibited a strong corrosion resistance after being immersed in an alkaline environment (pH=12.5) added with 0.1 M NaCl, and the charge transfer resistance (Rt) could reach 5.88×106 Ω·cm2 after immersion for 1600 h, which was approximately 2.5 times the initial Rt value. Moreover, it was found that the film has a self-heal property when being damaged beyond the pitting potential. The anticorrosion mechanism of the film and its self-healing mechanism were discussed in depth in this study.

EIS Study of Molybdate Conversion Coatings Formed on AZ91D Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 279-285
Author(s):  
Li Ping Wu ◽  
Zhong Dong Yang
Keyword(s):  
Corrosion Resistance ◽  
Charge Transfer ◽  
Magnesium Alloy ◽  
Charge Transfer Resistance ◽  
Conversion Coating ◽  
Conversion Coatings ◽  
Bath Composition ◽  
Optimum Conditions ◽  
Transfer Resistance ◽  
Az91d Magnesium Alloy

An environmentally friendly molybdate conversion coating based surface treatment was developed for AZ91D magnesium alloy. The EIS technique was employed to study the effects of the conversion bath composition and temperature on the corrosion protection performance of molybdate conversion coatings on AZ91D magnesium alloys. The optimum conditions under which obtained conversion coatings showed the best corrosion resistance were determined. The Nyquist results showed that the value of charge transfer resistance increased by 22.5 times for the sample treated in the optimized molybdate conversion bath.

scholarly journals Austenitic-ferritic stainless steel containing niobium

2013 ◽  
Vol 66 (4) ◽  
pp. 467-471
Author(s):  
André Itman Filho ◽  
Wandercleiton da Silva Cardoso ◽  
Leonardo Cabral Gontijo ◽  
Rosana Vilarim da Silva ◽  
Luiz Carlos Casteletti
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Charge Transfer ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Charge Transfer Resistance ◽  
Chemical Compositions ◽  
Transfer Resistance ◽  
Ferritic Stainless Steels

The austenitic-ferritic stainless steels present a better combination of mechanical properties and stress corrosion resistance than the ferritic or austenitic ones. The microstructures of these steels depend on the chemical compositions and heat treatments. In these steels, solidification starts at about 1450ºC with the formation of ferrite, austenite at about 1300ºC and sigma phase in the range of 600 to 950ºC.The latter undertakes the corrosion resistance and the toughness of these steels. According to literature, niobium has a great influence in the transformation phase of austenitic-ferritic stainless steels. This study evaluated the effect of niobium in the microstructure, microhardness and charge transfer resistance of one austenitic-ferritic stainless steel. The samples were annealed at 1050ºC and aged at 850ºC to promote formation of the sigma phase. The corrosion testes were carried out in artificial saliva solution. The addition of 0.5% Nb in the steel led to the formation of the Laves phase.This phase, associated with the sigma phase, increases the hardness of the steel, although with a reduction in the values of the charge transfer resistance.

scholarly journals Influence of digene tablet juice orally taken in on the corrosion resistance of orthodontic wire made of SS 18/8 in presence of artificial saliva

2021 ◽  
Vol 62 (3) ◽  
pp. 220-227
Author(s):  
Chandrasekaran Priya ◽  
Antony Regis ◽  
Susai Rajendran
Keyword(s):  
Corrosion Resistance ◽  
Charge Transfer ◽  
Double Layer ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Double Layer Capacitance ◽  
Orthodontic Wires ◽  
Transfer Resistance ◽  
Orthodontic Wire

Dentists make use of orthodontic wires such as SS 18/8, SS 316, Ni-Cr etc., to regulate the growth of teeth. In the saliva environment these wires undergo corrosion. Aside from this, they undergo corrosion by the food items, juices and Tablets orally in taken. Corrosion resistance of SS 18/8 alloy in artificial saliva (AS) , in the absence and presence of Digene Tablet juice, has been investigated by polarization and AC impendance techniques. It is inferred that corrosion resistance of SS 18/8 alloy in artificial saliva decreases in presence of Digene Tablet. This is exposed by decrease in Linear Polarization Resistance (LPR) value, Charge transfer resistance (Rt) value, in impedance value, and increase in corrosion current and double layer capacitance value(Cdl). In presence of Digene Tablet, the LPR value decreases from 3488228 to 1629535 Ohmcm2. The corrosion current value increases from 1.447 x10-8 to 2.637x10-8A/cm2 . The Charge transfer resistance (Rt) value decreases from 37796 to 10481Ohmcm2 . The double layer capacitance value increases from 1.349x10-10 F/cm2 to 4.866x10-10F/cm2. The impedance value decreases from 4.857 to 4.428. Hence it implies that people with orthodontic wire made of SS 18/8 alloy should avoid taking Digene Tablet juice orally.

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
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