scholarly journals Data on the Microstructure and Passivation Behavior for NO7718 and NO7208 Nickel Alloys in Corrosive Media

2018 ◽  
Vol 34 (5) ◽  
pp. 2435-2439
Author(s):  
Roland Tolulope Loto
Keyword(s):  
Nickel Alloys ◽  
Chloride Ion ◽  
Open Circuit ◽  
Ion Concentration ◽  
Polarization Data ◽  
Corrosive Media ◽  
Potential Measurement ◽  
Passive Behavior ◽  
Qualitative Relationship ◽  
Transition Curves

Potentiodynamic polarization data for nickel alloys N07718 and N07208 in 2M H2SO4 solution at 0% - 5% NaCl concentrations are presented in tabular form showing the qualitative relationship between the corrosion resistance, passivation behavior and interfacial redox reactions of the alloys with the increase in chloride ion concentration. Tafel plots from the polarization test are presented to show the anodic-cathodic transition curves with respect to variable applied potential and scan rate. Data on open circuit potential measurement for the 1200s showed the active-passive behavior of both alloys and their thermodynamic stability in the acid solution. Optical micro-analytical images of the alloys before corrosion and at 0%, 0.5% and 5% NaCl after corrosion are presented for morphological and comparative analysis.

Induction Time Studies of Fe18Cr and 430 SS under Open Circuit Conditions in Chloride-Containing Sulfuric Acid

CORROSION ◽  
1984 ◽  
Vol 40 (4) ◽  
pp. 140-146 ◽  
Author(s):  
B. S. Covino ◽  
M. Rosen
Keyword(s):  
Induction Time ◽  
Chloride Ion ◽  
Open Circuit ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Short Film ◽  
Corrosion Resistant ◽  
Passive Behavior ◽  
Induction Times ◽  
Aisi 430

Abstract In order to promote the effective and efficient application of corrosion resistant metals and alloys in mineral processing environments, the Bureau of Mines, U.S. Department of the Interior, has characterized the effect of aggressive ions on the corrosion and passive behavior of two stainless steels, Fe18Cr and AISI 430 SS. Samples prepassivated in oxygen saturated 1 N H2SO4 at 0.6 V NHE and then released to open circuit and aged for times ranging from 10 min to 80,000 min (55 days), were subsequently exposed to chloride ion concentrations ranging from 5 to 44 parts per thousand (ppt). Susceptibility to chloride ion attack was determined as a function of time in solution (film aging time), chloride ion concentration [Cl−], and open circuit potentials (E) at the time chloride was added by measuring the amount of time (induction time, t) required for a sample to begin corroding after adding the chloride ion. The experimentally determined induction times were fitted to an equation of the form: 1/t=K Em[Cl−]n where K, m, and n are empirically determined constants. Results obtained for short (<100 min) aging times were different from those for long (100 to 80,000 min) aging times. For Fe18Cr exposed for short film aging times prior to addition of the chloride, larger [Cl−] resulted in shorter induction times, and higher values of E resulted in longer induction times. For 430 SS exposed for short film aging times, and for 430 SS and Fe18Cr exposed for longer film aging times prior to addition of chloride ions, both larger [Cl−] and higher values of E resulted in shorter induction times.

Corrosion Behavior of Nickel and Inconel in Acidic Chloride Solutions

CORROSION ◽  
1969 ◽  
Vol 25 (4) ◽  
pp. 151-156 ◽  
Author(s):  
D. L. PIRON ◽  
E. P. KOUTSOUKOS ◽  
KEN NOBE
Keyword(s):  
Corrosion Behavior ◽  
Chloride Ion ◽  
Open Circuit ◽  
Differential Capacitance ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Acidic Solutions ◽  
Acidic Chloride ◽  
Passivation Potential ◽  
Passive Current

Abstract The corrosion behavior of nickel and Inconel in acidic solutions has been investigated by polarization methods. The cathodic Tafel slope for the h.e.r. of nickel in de-aerated 1N H2SO4 and the corresponding exchange current density were 135 mv and 3.4 μa/cm2. Two cathodic Tafel slopes and exchange currents for the h.e.r. were obtained for Inconel in the same solution: 50 mv and 0.22 /μa/cm2; 115 mv and 7.2 μa/cm2. With increase in concentration of chloride ions, the corrosion potential of nickel decreased and the open circuit differential capacitance increased. Each parameter approached a constant value at the higher chloride ion concentrations. Anodic polarization of both metals showed that the primary passivation potential, the critical and passive current densities increased with increase in chloride ion concentration. The passivity of Inconel was shown to be superior to that of nickel in acidic solutions in the absence and presence of chloride ions.

scholarly journals Stress Corrosion Behavior of Ungrouted Pretensioned Concrete Beams

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Velu Saraswathy ◽  
Han-Seung Lee ◽  
Subbiah Karthick ◽  
Seung-Jun Kwon
Keyword(s):  
Stress Corrosion ◽  
Corrosion Behavior ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Steel Wire ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Simultaneous Action ◽  
Corrosive Media ◽  
Potential Measurement

Prestressed concrete beams of size 150 × 150 × 1000 mm were designed, and two bonded cold-drawn 7 mm steel wires were stressed at 70% UTS under service conditions before concreting. The beams were cast with M40 grade concrete mix with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of cement and cured for 28 days. After 28 days, the stretching forces were released, the prestressing steel wire was allowed to regain its original length, the tensile stresses were transformed into a compressive stress in the concrete, and the stress corrosion behavior was assessed. Stress corrosion cracking (SCC) is due to the simultaneous action of stress, corrosive media, and material properties. The stress corrosion behavior of ungrouted pretensioned steel was assessed by using various electrochemical techniques such as electrochemical noise, open-circuit potential measurement, AC impedance, and potentiodynamic polarization measurements. The same experiments were conducted for rebars embedded in the concrete beam with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of chloride. After 30 days of exposure, the beams were tested for their flexural strength measurements to find out the load-bearing capacity.

scholarly journals Study on the Electrochemical Performance of Sacrificial Anode Interfered by DC Stray Current

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Qingmiao Ding ◽  
Tao Shen ◽  
Yanyu Cui ◽  
Juan Xue
Keyword(s):  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Chloride Ion ◽  
Open Circuit ◽  
Ion Concentration ◽  
Effect Of Temperature ◽  
Sacrificial Anode ◽  
Stray Current ◽  
Anode Corrosion ◽  
The Impact

The influence of sacrificial anode electrochemical properties interfered by direct stray current (DC) of 0 V, 1 V, 3 V, and 5 V, with different chloride ion concentration and temperature, was studied by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and polarization curves. The specific performance was as follows: as the DC interference voltage increased from 0 V to 5 V, the degree of positive migration of the sacrificial anode open circuit potential increased. The effect of temperature in DC interference voltage environment on sacrificial anode corrosion was not great, but the low temperature of 10°C could slow down the sacrificial anode corrosion and maintain good work efficiency. With the increase of the ambient temperature, the degree of corrosion of the sacrificial anode was deepened. As the chloride ion concentration in DC interference voltage environment increased from 0% to 0.3%, the degree of positive migration of the sacrificial anode open circuit potential increased. The higher the chloride ion concentration was, the greater the impact on the performance of the sacrificial anode was.

scholarly journals First Attempts of the Use of 195Pt NMR of Phenylbenzothiazole Complexes as Spectroscopic Technique for the Cancer Diagnosis

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3970 ◽  
Author(s):  
Bruna T. L. Pereira ◽  
Mateus A. Gonçalves ◽  
Daiana T. Mancini ◽  
Kamil Kuca ◽  
Teodorico C. Ramalho
Keyword(s):  
Cancer Treatment ◽  
Cancer Diagnosis ◽  
Density Functional ◽  
Chemical Shifts ◽  
Chloride Ion ◽  
Platinum Complexes ◽  
Dft Method ◽  
Ion Concentration ◽  
Implicit Solvent ◽  
Early Cancer Diagnosis

Platinum complexes have been studied for cancer treatment for several decades. Furthermore, another important platinum characteristic is related to its chemical shifts, in which some studies have shown that the 195Pt chemical shifts are very sensitive to the environment, coordination sphere, and oxidation state. Based on this relevant feature, Pt complexes can be proposed as potential probes for NMR spectroscopy, as the chemical shifts values will be different in different tissues (healthy and damaged) Therefore, in this paper, the main goal was to investigate the behavior of Pt chemical shifts in the different environments. Calculations were carried out in vacuum, implicit solvent, and inside the active site of P13K enzyme, which is related with breast cancer, using the density functional theory (DFT) method. Moreover, the investigation of platinum complexes with a selective moiety can contribute to early cancer diagnosis. Accordingly, the Pt complexes selected for this study presented a selective moiety, the 2-(4′aminophenyl)benzothiazole derivative. More specifically, two Pt complexes were used herein: One containing chlorine ligands and one containing water in place of chlorine. Some studies have shown that platinum complexes coordinated to chlorine atoms may suffer hydrolyses inside the cell due to the low chloride ion concentration. Thus, the same calculations were performed for both complexes. The results showed that both complexes presented different chemical shift values in the different proposed environments. Therefore, this paper shows that platinum complexes can be a potential probe in biological systems, and they should be studied not only for cancer treatment, but also for diagnosis.

scholarly journals Broadband dielectric spectroscopy for monitoring temperature-dependent chloride ion motion in BiOCl plates

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Dariusz Łukowiec ◽  
Patryk Włodarczyk
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Chloride Ion ◽  
Ion Source ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Broadband Dielectric Spectroscopy ◽  
Free Chloride ◽  
Structure Rebuilding

AbstractThe dielectric properties and electrical conduction mechanism of bismuth oxychloride (BiOCl) plates synthesized using chloramine-T as the chloride ion source were investigated. Thermally-activated structure rebuilding was monitored using broadband dielectric spectroscopy, which showed that the onset temperature of this process was 283 K. This rebuilding was related to the introduction of free chloride ions into [Bi2O2]2+ layers and their growth, which increased the intensity of the (101) diffraction peak. The electrical conductivity and dielectric permittivity were related to the movement of chloride ions between plates (in the low-frequency region), the interplanar motion of Cl− ions at higher frequencies, vibrations of these ions, and charge carrier hopping at frequencies above 10 kHz. The influence of the free chloride ion concentration on the electrical conductivity was also described. Structure rebuilding was associated with a lower concentration of free chloride ions, which significantly decreased the conductivity. According to the analysis, the BiOCl plate conductivity was related to the movement of Cl− ions, not electrons.

scholarly journals Chloride-ion concentration dependence of molecular dimension in the acid-denatured state of equine β-lactoglobulin

2007 ◽  
Vol 40 (s1) ◽  
pp. s213-s216 ◽  
Author(s):  
Yoshiteru Yamada ◽  
Takeo Yajima ◽  
Seiichi Tsukamoto ◽  
Kanako Nakagawa ◽  
Kazuo Fujiwara ◽  
...  
Keyword(s):  
Concentration Dependence ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Denatured State ◽  
Molecular Dimension ◽  
Β Lactoglobulin
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