Enhancing Effect of Chloride Ions on the Autocatalytic Process of Ag(I) Reduction by Co(II) Complexes

In this work, the possibilities of increasing the rate of electroless silver plating without a rise in the concentration of reactants or elevation of temperature were studied. The effect of halide additive, namely chloride ions, on the rate of electroless silver deposition was investigated, using conventional chemical kinetics and electrochemical techniques. It was found that the deposition rate of electroless silver increased 2–3 times in the presence of 10–20 mM of chlorides, preserving sufficient stability of the solution.

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Effects of Stress and Plastic Deformation on the Corrosion of Steel

CORROSION ◽

10.5006/0010-9312-26.5.189 ◽

1970 ◽

Vol 26 (5) ◽

pp. 189-199 ◽

Cited By ~ 17

Author(s):

W. D. FRANCE

Keyword(s):

Plastic Deformation ◽

Electrochemical Techniques ◽

Chloride Ions ◽

Localized Corrosion ◽

Dissolution Behavior ◽

Potential Range ◽

Chemical Corrosion ◽

Effects Of Ph ◽

Current Densities ◽

The Stability

Abstract The rate and type of corrosion exhibited by mild steel in the annealed, stressed, and plastically deformed state have been investigated. Precise electrochemical techniques provided potential and polarization data to supplement the results of chemical corrosion tests. Experiments were conducted in 0.6M NH4NO3 solutions in which steel exhibits active-passive dissolution behavior as well as localized corrosion. At active potentials, the anodic polarization curves for annealed and deformed specimens were nearly identical, with only slight increases in current densities for the deformed steel. Results at passive potentials demonstrated that increased plastic deformation can markedly decrease the passive potential range, the stability of passivity, and the ability to passivate. At certain passive potentials, the deformed steel exhibited current densities that were 400 times greater than those for annealed steel. The effects of pH, chloride ions, and crevices on the corrosion of deformed steel were examined in detail. The differences between the dissolution behavior of annealed and deformed steel were most distinctive in the approximate pH range of 3 to 6. This work is relevant to the understanding of the initiation of localized corrosion and to anodic protection.

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Longevity Aspects of Potable Water Disinfected by Ionic Silver: Kinetic Experiments and Modeling

Water ◽

10.3390/w12010258 ◽

2020 ◽

Vol 12 (1) ◽

pp. 258 ◽

Cited By ~ 1

Author(s):

Maria Petala ◽

Vasilios Tsiridis ◽

Efthymios Darakas ◽

Margaritis Kostoglou

Keyword(s):

Deposition Rate ◽

Distribution Systems ◽

Potable Water ◽

Material Selection ◽

Space Station ◽

Water Storage ◽

Bulk Water ◽

Silver Concentration ◽

Ti Alloy ◽

Silver Deposition

In the International Space Station (ISS), Russian and European cosmonauts drink water disinfected by dissolved silver. For this to be effective, the concentration of silver should remain above a certain threshold from the moment of its initial disposition in storage tanks on earth until its final consumption in ISS. Unfortunately, during water tanks transportation to ISS and during storage in ISS, silver concentration has been reported to decrease intensively beyond any reason. This work examines the effect of different materials used in ISS water storage and distribution systems on the reduction of silver concentration. An experimental campaign has been organized where passivated stainless steel (SS), passivated and electropolished SS and titanium alloy coupons (official ISS grades) are exposed to simulated ISS potable water at different silver concentrations, different surface to volume ratios, and at stagnant or flow conditions. The evolution of silver concentration remaining in the bulk water is recorded with respect to the exposure time. A reaction engineering model for the Ag loss to the coupons is developed. The model is fitted to the experimental data in order to derive the reaction rate expression and the corresponding parameters. For passivated SS and electropolished SS the silver deposition rate depends on the initial silver concentration in water but is rather unaffected by the progress of silver deposition on the surface. On the other hand, for Ti alloy, while silver deposition rate still depends on initial silver concentration, it decreases continuously as silver deposition on the surface advances, implying that Ti alloy surface becomes gradually saturated and so prevents further silver deposition. Such a model can be useful for material selection and design of water storage and distribution facilities for ISS.

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DYNAMICS AND TOPOGRAPHY OF QUASI-2D NEEDLE-LIKE SILVER ELECTROCHEMICAL DEPOSITS UNDER A QUASI-STEADY-STATE REGIME

Surface Review and Letters ◽

10.1142/s0218625x09013189 ◽

2009 ◽

Vol 16 (05) ◽

pp. 697-713

Author(s):

M. A. PASQUALE ◽

J. L. VICENTE ◽

A. J. ARVIA

Keyword(s):

Steady State ◽

Mass Transport ◽

Deposition Rate ◽

Silver Ion ◽

Stage Iii ◽

Surface Relaxation ◽

Scanning Electron Micrographs ◽

Quasi Steady State ◽

Silver Deposition ◽

Needle Growth

The electrochemical formation of single silver needles from aqueous silver sulfate was studied under both potentiostatic and galvanostatic conditions utilizing different quasi-2D cells. Under potentiostatic conditions, four (I–IV) stages of growth were distinguished. Stage III involved single needle growth under a quasi-steady-state (q-ss) regime in which, at the millimeter scale, the tip profile remained almost unchanged. Fast growing needles exhibited a truncated quasi-conical tip, and slow growing ones approached prolate hemispheroids. At stage III, the almost constant q-ss silver deposition rate was evaluated from the tip front displacement (dL z /dt) perpendicularly to the tangential plane of the tip. For the cathode to anode potential difference in the range -1.00 ≤ E c-a ≤ -0.22 V , values of (dL z /dt) in the range 0.08–2.0 μm s-1 were obtained. At the needle stem, the q-ss radial silver deposition rate (dL x /dt) was about two orders of magnitude lower than (dL z /dt). The transition from stage III to IV was characterized by tip thickening, i.e. a change in the tip q-conical profile to that of a prolate hemispheroid, and eventual tip splitting. Scanning electron micrographs at the micrometer scale of single silver needle tips from potentiostatic runs showed either a defined crystallography or an irregular topography covered by a large number of tiny crystals. In contrast, stems were always faceted. This difference indicated that surface relaxation processes following silver ion mass transport and discharge played a relevant role in the needle growth mode. At stage III, the growth regime is described utilizing a dual diffusion (D) and migration (M) model consisting of a DM direct contribution that becomes dominant at the needle stem, and a space charge (SC)-assisted DM contribution that operates at the tip apex. This explanation is consistent with the local cathodic current density values, the concentration ratio of silver clusters at the stem and tip apex surface, and the distinct kinetic behavior of needles produced from potentiostatic and galvanostatic runs. The complex link between mass transport phenomena of silver ions from the binary solution side, the silver ion discharge at the interface and the surface relaxation of silver adatoms and clusters at the metal lattice shed new light on the aspects of single silver needle formation.

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Comparison of Electrochemical Behavior of Cu-10Ni-10Zn Alloy and Cu in Aqueous Solutions

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2014-0627 ◽

2015 ◽

Vol 229 (3) ◽

Cited By ~ 1

Author(s):

Waheed A. Badawy ◽

Mohamed M. El-Rabiei ◽

Hashem M. Nady ◽

Mohammed A. Samy

Keyword(s):

Electrochemical Behavior ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Pure Copper ◽

Open Circuit ◽

Chloride Ions ◽

Alloy Surface ◽

Metallic Surface ◽

Copper Dissolution ◽

Basic Solutions

AbstractThe electrochemical behavior of Cu-10Ni-10Zn alloy and Cu was investigated in acidic, neutral and basic solutions. The effect of chloride ions in neutral solutions was also studied. Conventional electrochemical techniques and electrochemical impedance spectroscopy were used. The corrosion rate of these materials in acidic solutions is relatively high compared to that in neutral or basic solutions. The open-circuit potential of the alloy is nearly the same as that of pure copper in the different media, indicating that the processes which occur on the alloy surface are mainly governed by copper dissolution. In chloride solutions the rate of Cu corrosion is remarkably high. In the alloy, the copper dissolution was suppressed by the presence of nickel and zinc, due to the formation of complex oxide layers. The impedance data were fitted to equivalent circuit models that explain the different electrochemical processes occurring at the electrode/electrolyte interface. SEM and EDAX have shown that the alloy surface is enriched with Ni. In neutral solutions the chloride ions are penetrating the metallic surface.

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Effect of Nd3+ Ion Concentration on the Corrosion Resistance of API X70 Steel in Chloride-Rich Environments

Advances in Materials Science and Engineering ◽

10.1155/2018/9328317 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 4

Author(s):

D. M. Martinez de la Escalera ◽

J. J. Ramos-Hernandez ◽

E. Porcayo-Palafox ◽

J. Porcayo-Calderon ◽

J. G. Gonzalez-Rodriguez ◽

...

Keyword(s):

Open Circuit Potential ◽

Inhibition Efficiency ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Protective Layer ◽

Open Circuit ◽

Chloride Ions ◽

Ion Concentration ◽

Linear Polarization Resistance ◽

Potentiodynamic Polarization Curves

In this study, the effect of the addition of Nd3+ ions as a corrosion inhibitor of the API X70 steel in a medium rich in chlorides was evaluated. The performance of the Nd3+ ions was evaluated by means of electrochemical techniques such as potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy, as well as by means of scanning electron microscopy and EDS measurements. The results showed that Nd3+ ions reduce the corrosion rate of steel at concentrations as low as 0.001 M Nd3+. At higher concentrations, the inhibition efficiency was only slightly affected although the concentration of chloride ions was increased by the addition of the inhibitor. The adsorption of the Nd3+ ions promotes the formation of a protective layer of oxides/hydroxides on the metal surface, thereby reducing the exchange rate of electrons. Nd3+ ions act as a mixed inhibitor with a strong predominant cathodic effect.

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In situ and ex situ characterization of a Fe-Cr-Ni alloy in mouthwashes and Hank’s solution

Chemical Papers ◽

10.2478/s11696-008-0031-1 ◽

2008 ◽

Vol 62 (3) ◽

Cited By ~ 1

Author(s):

Dane Cestarolli ◽

Valéria Alves ◽

Luís Silva

Keyword(s):

Corrosion Resistance ◽

Electrochemical Techniques ◽

Passive Layer ◽

Chloride Ions ◽

Localized Corrosion ◽

Ex Situ ◽

Ni Alloy ◽

Hank’S Solution

AbstractThe aim of the present study was to classify the surface oxide layers formed on a Fe-Cr-Ni alloy according to their corrosion resistance in Hank’s solution and mouthwashes by SEM and electrochemical techniques. The SEM micrographs showed the presence of localized corrosion and the polarization curves showed that the passive layer is less stable in the presence of Hank’s solution than of mouthwashes, as a result of the presence of chloride ions.

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Quantitative Non-Linear Effect of High Ambient Temperature on Chloride Threshold Value for Steel Reinforcement Corrosion in Concrete under Extreme Boundary Conditions

Materials ◽

10.3390/ma14247595 ◽

2021 ◽

Vol 14 (24) ◽

pp. 7595

Author(s):

Abdulrahman M. Alhozaimy ◽

Mshtaq Ahmed ◽

Raja Rizwan Hussain ◽

Abdulaziz Al-Negheimish

Keyword(s):

Corrosion Rate ◽

Corrosion Potential ◽

Electrochemical Techniques ◽

Chloride Content ◽

Threshold Value ◽

Chloride Ions ◽

Water Soluble ◽

Linear Effect ◽

Chloride Threshold ◽

Exposure Temperature

This paper investigates the effect of high ambient temperatures on the chloride threshold value for reinforced concrete (RC) structures. Two commonly available carbon steel rebars were investigated under four different exposure temperatures (20 °C (68 °F), 35 °C (95 °F), 50 °C (122 °F), and 65 °C (149 °C)) using environmental chambers at a constant relative humidity of 80%. For each temperature, six different levels of added chloride ions (0.00%, 0.15%, 0.30%, 0.60%, 0.90%, and 1.20% by weight of cement) were used to study the chloride threshold value. Corrosion initiation was detected by monitoring the corrosion potential and corrosion rate using electrochemical techniques. The water-soluble (free) and acid-soluble (total) chlorides were determined using potentiometric titration according to the relevant ASTM standards. The threshold chloride content for each exposure temperature was determined by analyzing the corrosion potential, corrosion rate, and chloride content of each specimen. The results showed that the chloride threshold values were significantly temperature-dependent. At temperatures of 20 °C (68 °F) and 35 °C (95 °F), the chloride threshold value (expressed as free chlorides) was approximately 0.95% by weight of cement. However, as the temperature increased to 50 °C (122 °F), the chloride threshold decreased significantly to approximately 0.70% by weight of cement. The reduction in the chloride threshold value became more dramatic at an exposure temperature of 65 °C (149 °F), decreasing to approximately 0.25% by weight of cement. The trends were similar for the rebars from the two sources, indicating that the rebar source had little influence on the chloride threshold value.

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Electrochemical behavior of lanthanum and yttrium ions in two molten chlorides with different oxoacidic properties: The eutectic LiCl-KCl and the equimolar mixture CaCl2-NaCl

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb0302109c ◽

2003 ◽

Vol 39 (1-2) ◽

pp. 109-135 ◽

Cited By ~ 28

Author(s):

Y. Castrillejo ◽

M.R. Bermejo ◽

A.M. Martínez ◽

Arocas Díaz

Keyword(s):

Electrochemical Behavior ◽

Electrochemical Techniques ◽

Three Dimensional ◽

Earth Metal ◽

Active Species ◽

Chloride Ions ◽

Equimolar Mixture ◽

Transport Parameters ◽

Tungsten Electrode ◽

Simple Diffusion

The electrochemical behavior of LaCl3 and YCl3 was studied in two molten chloride mixtures with different oxoacidic properties, the eutectic LiCl-KCl and the equimolar CaCl2-NaCl melt at different temperatures. The stable oxidation states of both elements have been found to be (III) and (0) in both melts, and it was found that both La(III) and Y(III) cations were less solvated by the chloride ions in the calcium-based melt, which was explained by the stability of CaCl4 2- ions in that melt. Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electro active species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, the electro crystallization of lanthanum and yttrium seems to be the controlling electrochemical step while in CaCl2-NaCl this phenomenon has not been observed. That was explained in terms of the differences in the physicochemical properties of the systems, especially interfacial tensions. In the eutectic LiCl-KCl chronoamperometric studies indicated instantaneous and three dimensional nucleation and crystal growth of lanthanum and yttrium whatever the applied over potential of the rare earth metal is, whereas in the equimolar mixture CaCl2-NaCl, the corresponding electrochemical exchanges were found to be quasi-reversible, and the values of the kinetic parameters, K0 and ?,were obtained for both reactions. Mass transport towards the electrode is a simple diffusion process, and the diffusion coefficients have been calculated. The validity of the Arrhenius law was also verified by plotting the variation of the logarithm of the diffusion coefficient versus 1/T.

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Electrochemical Study of Clean and Pre-Corroded Reinforcements Embedded in Mortar Samples with Variable Amounts of Chloride Ions

Materials ◽

10.3390/ma14226883 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6883

Author(s):

María de las Nieves González ◽

María Isabel Prieto ◽

Alfonso Cobo ◽

Fernando Israel Olmedo

Keyword(s):

Corrosion Potential ◽

Cement Mortar ◽

Electrochemical Techniques ◽

Chloride Ion ◽

Chloride Ions ◽

Corrosion Products ◽

The Other ◽

Steel Bars ◽

One Year ◽

Corrosion Of Steel

The present study investigates the possibility of re-surfacing previously corroded reinforcements and the suitability of the two electrochemical techniques that are widely used to determine the state of corrosion of steel (the corrosion potential Ecorr and the corrosion rate icorr). In order to test this, 32 pre-corroded B500SD reinforcing steel bars have been used for one year, where half of the bars have been cleaned to eliminate corrosion products. The other half have been maintained with the generated corrosion products. Subsequently, the bars have been embedded in cement mortar samples with variable amounts of chloride ion, and Ecorr and icorr have been measured for 250 days. The results showed that it is not possible to rework the reinforcement without removing corrosion products and that it is not possible to predict the passive or active state of steel by measuring Ecorr only.

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Analytical techniques for determination and control of silica content in the water in thermal power plants

Hemijska industrija ◽

10.2298/hemind140914084i ◽

2015 ◽

Vol 69 (6) ◽

pp. 605-616

Author(s):

Natasa Ignjatovic ◽

Maja Ilic ◽

Ljubinka Rajakovic

Keyword(s):

Power Plants ◽

Thermal Power ◽

Electrochemical Techniques ◽

Chloride Ions ◽

Molecular Forms ◽

Piping System ◽

Thermal Power Plants ◽

Ultrapure Water ◽

Advantages And Disadvantages

Ultrapure water with minimum contents of impurities is used for the preparation of steam in thermal power plants. More recently it has been found that the corrosion process is also influenced by sodium ions, chloride ions, and all forms of silicon in water. At higher temperatures and under high pressure the less soluble compounds of silicon are extracted, which form deposits on the walls of the boiler, the piping system and the turbine blades. Silicon is found in water in the form of different types (species) which are characterized by specific physical and chemical properties. Distinctions can be made between highly reactive species of ionic (silicate anions) and molecular forms (silicic acid) and relatively inert types (suspended, colloidal, and polymerized silicon). The determination of various forms of silicon in water is a complex analytical task. This paper covers relevant research in the field of silicon specification analysis. Maintaining the unchanged, original composition of silicon species during various stages of analysis (sample collection, storage, and conservation) has been given special attention. A large number of methods and procedures have been developed for the analysis of species of silicon, including chromatographic, spectroscopic and electrochemical techniques and combinations thereof. The techniques used for determining both the total amount and individual forms of silicon have been singled out. There is also an overview of the coupled techniques used most frequently in practice by using the methodology which involves preliminary separation of species and then individual specification. The paper offers an overview of analytical properties, advantages and disadvantages of the most representative analytical methods developed specifically for the analysis of silicon species in ultrapure water. The most important studies focusing on the silicon species in water have been highlighted and presented in detail. The determination of silicon content in water is of great importance because of various effects of silicon species (corrodibility and toxicity) and the selection of methods for the efficient removal of silicon from water.

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