Silver Chloride Reference Electrode Research Articles

Влияние катодного внедрения хрома в цинковое покрытие на его защитную способность

The influence of cathodic introduction of chromium into the surface layers of a zinc coating on the change in its corrosion resistance has been determined. Electrodeposition of zinc from electrolytes of various compositions was carried out on electrodes made of St3 steel. TsO grade zinc was used as an anode. Preliminary steel electrode was preparated treating the steel surface of in the potentiostatic mode of pre-phase deposition (DPD) at a potential 50 mV more positive than the equilibrium potential of zinc (Ep) in the working electrolyte for 5 minutes. The zinc coating was applied in potentiostatic mode at a potential of –1.20 V relative to the silver chloride reference electrode. The introduction of chromium into the electrodeposited zinc coating was carried out in the potential range from –0.97 to –1.15 V from electrolytes containing trivalent chromium salt. The results of X-ray fluorescence analysis of the component composition of working electrodes after cathodic introduction of chromium, the morphology of the formed surface obtained using scanning electron microscopy, indicate the presence of chromium in the coating composition and its effect on the structure of the deposit. The corrosion resistance of modified zinc coatings by cathodic introduction of chromium at potentials of –1.05 V and –1.10 V for 5 minutes exceeds this characteristic of chromated zinc.

К вопросу использования контрольных электродов для технического диагностирования протекторов морских судов

The world statistics of fleet accidents indicate that the most dangerous type of damage to engineering structures are fragile destructions that occur suddenly and spread at high speed. The causes of brittle fractures are defects such as corrosion-fatigue cracks, which often occur due to active corrosion processes. Seawater contains a large number of microorganisms that contribute to the acceleration of corrosion and fouling of metal structures in contact with water. The main method of corrosion protection of systems and mechanisms of marine fishing vessels is tread protection. To increase the effectiveness of tread protection, it is necessary to improve the methods of technical diagnostics of treads in order to use new methods at ship repair plants and marine vessels. It is proposed to use control electrodes made of stainless steel for technical diagnostics of marine vessel protectors. Laboratory tests of a stainless steel electrode and a standard silver chloride reference electrode were performed. The experiment took place at the installation for technical diagnostics of marine protectors, which was specially developed at the Department of “Power Plants and Electrical Equipment of Ships” of the Kamchatka State Technical University. Control measurements of the potential of the working protector were performed for five days, while 50 single control measurements of the working potential of the protector were performed daily using each electrode. The accuracy of the measurement results was evaluated using a mathematical and statistical method. The results of diagnosing the potential of the tread, obtained using an electrode made of stainless steel, comply with regulatory requirements. The proposed type of electrode can be used by ship crews for technical diagnostics of marine vessel protectors.

Three-Dimensional Inkjet-Printed Electrochemical Sensor on Shape Memory Polymer for Aqueous Lead Detection

A simple, miniaturized, reproducible, and disposable 3D (inkjet-printed – additive manufacturing technology) gold plated electrochemical sensor (ECS) on shape memory polymer (SMP) has been reported in this article. This inkjet printed (IP) SMP based gold plated ECS is used to determine lead (II) in aqueous solution. The limit of detection of the proposed ECS is 7.6 μg/L (below USEPA approved detection limit – 15 μg/L). A detailed description of the design, fabrication, materials and reagents, optimization, reproducibility, and evaluation of the reported ECS is delineated in this article. The sensor consists of gold (Au) working electrode, Au counter electrode, and silver chloride (AgCl) reference electrode. Immersion gold plating technology is applied on IP silver (Ag) electrodes to fabricate Au working and counter electrodes. Chlorination using sodium hypochlorite solution is utilized to fabricate AgCl reference electrode. Sensor characterization, optimization, and evaluation are performed using cyclic voltammetry (CV) electrochemical analysis. The reported sensor has been utilized in case of 3 mM and 14.4 μg/L lead (II) diluted aqueous solution optimized using 0.1 M hydrochloric acid (HCl) for different aqueous samples i.e., deionized water and tap water. The electrochemical characterization i.e., electrochemical impedance spectroscopy (EIS) measurements for the reported electrode system (64.07±7.19 Ω) has also been introduced using phosphate buffer saline (PBS; pH 7.4). SMP incorporated IP ECS for lead (II) detection has been employed for the first time in this research. This technology has shown promising output in case of electrochemical sensing (lead (II) detection) due to increased effective electrode surface area (19.37 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) despite miniaturizing lateral surface area (4.19 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of the fabricated ECS.

Corrosion Resistance of Al0.5CoCrFeNiCuxAgy (x = 0.25, 0.5; y = 0, 0.1) High-Entropy Alloys in 0.5M H2SO4 Solution.

The electrochemical behavior of the as-cast Al0.5CoCrFeNiCuxAgy (x = 0.25, 0.5; y = 0, 0.1) high-entropy alloys (HEAs) in a 0.5M H2SO4 solution was studied. Polarization measurements were carried out in a standard three-electrode electrochemical cell at room temperature using a platinum counter electrode and a saturated silver chloride reference electrode. For Al0.5CoCrFeNiCu0.5 and Al0.5CoCrFeNiCu0.5Ag0.1, copper segregation along the grain boundaries was observed, which highly dissolved in the sulfuric acid solution and resulted in low corrosion resistance of the samples. Introducing Ag into Al0.5CoCrFeNiCu0.25 HEA led to the precipitation of a copper-silver eutectic structure, in which the copper regions were selectively dissolved in the sulfuric acid solution. Al0.5CoCrFeNiCu0.25 exhibited the best corrosion resistance with the corrosion current density of Icorr = 3.52 ± 0.02 μA/cm2, significantly superior to that of the Al0.5CoCrFeNi sample without copper and silver (Icorr = 6.05 ± 0.05 μA/cm2). Finally, the results indicated that suppressing elemental segregation by annealing or tailoring chemical composition is essential to improve the corrosion resistance of Al0.5CoCrFeNiCuxAgy HEAs.

Electrochemical synthesis of a hydrogen storage material based on lanthanum and nickel intermetallics in the equimolar KCl–NaCl melt

Co-reduction of lanthanum and nickel ions on inert tungsten and active nickel electrodes were studied using the methods of cyclic chronovoltammetry, chronopotentiometry and open circuit chronopotentiometry in equimolar KCl–NaCl at 973 K. When both lanthanum and nickel ions are present in equimolar KCl–NaCl, the voltammetry dependences demonstrate the nickel ions reduction wave in the region of potentials –(0.00–0.1) V and lanthanum ions reduction wave in the region of potentials –(1.85–1.9) V relative to a silver chloride reference electrode. There are two more reduction waves on the opposite sides of voltammograms in the regions of potentials –(1.5–1.6) V and –(1.75–1.8) V. These waves are associated with the reduction of lanthanum ions and their depolarization on metallic nickel preliminarily deposited on the tungsten electrode, which results in the formation of intermetallic LaxNiy phases. The (E–t) dependences of open circuit chronopotentiometry demonstrate a delay plateau, which corresponds to the time required for dissolution of separate phases of intermetallic compounds. LaNi2 and LaNi5 intermetallic phases were electrochemically synthesized at a definite concentration of lanthanum and nickel chlorides in equimolar KCl–NaCl. The synthesized lanthanum and nickel intermetallic compounds were characterized by the X-ray diffraction analysis, scanning electron microscopy and photon correlation spectroscopy.

К вопросу изготовления цинковых электродов сравнения для морских судов и кораблей

The article highlights the urgent problem of corrosion protection monitoring of sea-going vessels and ships. Nowadays, the ship teams provide the control by measuring the potential of the ship hull using reference electrodes. There are given the results of monitoring the corrosion protection of the hull of the sea-going vessel PM-15 project No. 304/III. The control system is based on the results of measuring the potential of the ship hull. The measurements were taken using a standard silver chloride reference electrode (SCE) and two nonstandard electrodes made of galvanized steel. In manufacturing the non-standard reference electrodes there were taken into account the requests of the crews of sea-going vessels of the Kamchatka fleet. Testing the reference electrodes of galvanized steel proves that the results of measuring the potential of the ship hull can be classified as accurate measurements in accordance with GOST R 8.736-2011. The measuring results are quite stable according to GOST R 8.736-2011. It has been stated that the cost of CSE is several times higher than the cost of reference electrodes made of galvanized steel. The process of storing and transporting CSE is more labour-intensive compared to the galvanized steel reference electrodes. The galvanized steel reference electrodes provided for protecting the marine hulls from corrosion are recommended for use. It has been inferred that manufacture and application of non-standard reference electrodes on ships can be provided by ship repair crews. The study results can be used by the crews of sea-going vessels to control the protection &#x0D; of ship hulls against corrosion.

Fluoride Content of Ready-to-Eat Infant Foods and Drinks in Australia.

The use of fluoride is effective in preventing dental caries. However, an excessive intake of fluoride leads to dental fluorosis, making it necessary to regularly monitor the fluoride intake especially for infants. There is hitherto a lack of information on fluoride content in infant foods from an Australian perspective. Therefore, this study aims to estimate the amount of fluoride content from a range of commercially available ready-to-eat (RTE) infant foods and drinks available in Australia. Based on an external calibration method, potentiometry involving a fluoride ion selective electrode and a silver|silver chloride reference electrode was conducted to analyse the fluoride content of a total of 326 solid food samples and 49 liquid food samples in this work. Our results showed an overall median (range) fluoride content of 0.16 (0.001-2.8) µg F/g of solid food samples, and 0.020 (0.002-1.2) µg F/mL of liquid food samples. In addition, ~77.5% of the liquid samples revealed a fluoride content < 0.05% µg F/mL. The highest variation of fluoride concentration (0.014-0.92 µg F/g) was found in formulas for ≥6 month-old infants. We have attributed the wide fluoride content variations in ready-to-eat infant foods and drinks to the processing steps, different ingredients and their origins, including water. In general, we found the fluoride content in most of the collected samples from Australian markets to be high and may therefore carry a risk of dental fluorosis. These results highlight the need for parents to receive appropriate information on the fluoride content of ready-to-eat infant food and drinks.

Voltammetric Detection of Inositol Using a Platinum Based Electrode

An electrochemical detection of inositol content using platinum (Pt)-based noble metal electrode is investigated. In this work, the electrochemical behavior of the platinum electrode has been studied and analyzed using a three-electrode system against a silver–silver chloride (Ag/AgCl) reference electrode and a steel counter electrode. Differential pulse voltammetry technique has been employed for this experimental study. A satisfactory linear range of operation was obtained from 50 to 400[Formula: see text][Formula: see text]M with [Formula: see text]M. Electrochemical responses for several inositol concentrations 50, 80, 100, 200, 300 and 400[Formula: see text][Formula: see text]M have also been analyzed using principal component analysis (PCA) with effective data clustering. A good class separability index (SI) was found to be 142.91. In addition, a prediction estimation of inositol contents using partial least square regression (PLSR) and principal component regression (PCR) algorithms were also evaluated and prediction accuracies of 93.69% and 93.71% were obtained, respectively. Moreover, the application of the Pt electrode over real orange juice sample extracts revealed satisfactory recovery rate of 96.18%. Thus, this technique of electrochemical system may be subjected for inositol detection in our daily-life food (especially juice, beverages) consumption.

Corrosion Resistance of AlxCoCrFeNiM (M = Ti, V, Si, Mn, Cu) High Entropy Alloys in NaCl and H2SO4 Solutions

The electrochemical behavior of as-cast AlxCoCrFeNiM (M = Ti, V, Si, Mn, Cu) high entropy alloys (HEAs) in 1 M NaCl and 0.5 M H2SO4 solutions is studied. Polarization measurements were carried out in a standard three-electrode electrochemical cell with a platinum auxiliary electrode using a P-30J potentiostat device. The potentials were measured relative to a saturated silver chloride reference electrode EVL-1M3 at room temperature (25 °C) with a sweep rate of 5 mV/s. It is shown that despite a wide passivation region, Al0.5CoCrFeNi1.6Ti0.7 HEA undergoes significant corrosion in both sodium chloride and sulfuric acid solutions and exhibits low corrosion potential and current density. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed that Ti-containing eutectic areas are the most susceptible regions to corrosion. Intergranular corrosion was found in Al0.25CoCrFeNiMn and Al0.25CoCrFeNiCu HEAs. Moreover, Al0.25CoCrFeNiCu possesses the smallest passivation interval ΔE among all the investigated HEAs. For samples with Ti, Mn, and Cu, a protective film layer is not formed on the surface of the phases enriched in these elements, or it is brittle and crumbles. For samples with Si and V, a passivating film is formed. Thus, Al0.45CoCrFeNiSi0.45 and Al0.25CoCrFeNiV HEAs exhibited the highest resistance in 1 M NaCl and 0.5 M H2SO4 corrosive environments, respectively.

Multi-pathway mechanism of polydopamine film formation at vertically aligned diamondised boron-doped carbon nanowalls

Boron-doped carbon nanowall (B:CNW) electrodes were used as a platform for studying the electropolymerisation of dopamine. Due to the unique properties of B:CNW, including the fast charge-transfer kinetics and high surface conductivity, a high degree of reversibility of redox reactions was achieved. Three separated redox peaks were observed on voltammograms and attributed to three fundamental reactions in the dopamine polymerisation mechanism: dopamine/dopamine quinone, leukodopaminechrome/dopaminechrome, and dihydroxyindole/indolequinone. The mechanism was also supported by the density functional theory calculations of the single point energy of the polydopamine structural units. Moreover, the electrochemical impedance spectroscopy experiments strongly suggest that the majority of th epolymerisation occurs only in the narrow range of potentials between +0.0 and +0.4 V vs. the silver chloride reference electrode. The concept of a resistor-like CPE element is introduced to facilitate the description of the electrochemical properties of B:CNW electrodes in a neutral electrolyte. Further, it is shown that electropolymerisation differs significantly as a function of pH. In acidic environments (pH 3–6) mostly the dopamine/dopamine quinone reaction can be seen, whereas in a more alkaline pH (8–10), the leukodopaminechrome/dopaminechrome reaction becomes dominant. The dihydroxyindole/indolequinone redox pair is seen only in a short pH interval between 7 and 8. Additionally, the kinetics of polymerisation is significantly boosted when the pH is more than 7. Together, these results provide insight into the complexity of the formation of polydopamine and can assist in better controlling the properties of electropolymerised dopamine films.

Вплив природи електроліту на електрохімічні властивості вуглецевого матеріалу рослинного походження

Non-aqueous electrolytes are advantageous for power sources due to the increase in the operating voltage since their electrochemical stability range is much wider. It should be noted that the capacitor’s capacitance depends on the capacitance provided by the electrode material, expressed in F/g, while its voltage and resistance depend on the electrolyte. Therefore, it is very important to study the electrochemical properties of carbon material in aqueous and organic electrolytes and to determine the effect of the electrolyte on the capacitance of the capacitor formed on its basis. The cathode mixture was made of porous carbon material obtained from biomass and a binding additive. Then, it was pressed onto a nickel grid with an area of 0,5 cm2. A 30% aqueous solution of potassium hydroxide (KOH) and a 0,7-molar solution of tetraethyl ammonium tetrafluoroborate ([C2 H5 ]4 NBF4) in acetonitrile (CH3CN) was used as the electrolyte. The measurements were carried out using two- and three-electrode schemes with a silver chloride reference electrode. Modeling impedance data to equivalent electrical circuits has assisted to establish the influence of the volume charge region in the electrode material on the capacitor’s capacitive characteristics. The specific capacitance values of 125 F/g in KOH and 101 F/g in [C2 H5 ]4 NBF4 are determined by the electrolyte type used and the nature of salts and bases dissolved in it. The practical significance of the obtained results is the application of the developed methods for obtaining carbon material with developed micro- and mesoporous structures and improved physicochemical properties.

К вопросу использования медных электродов для контроля защищенности от коррозии стальных корпусов судов и кораблей

The paper focuses on the reasons for the lack of proper control of the operation of the electrochemical protective systems of sea vessels, such as the absence of convenient technical equipment, primarily the reference electrodes, as well as the imperfection of the silver chloride reference electrode. There is considered the approach to the development of easy-to-use reference electrodes. A standard silver chloride reference electrode was used as the first electrode; experimental electrodes made of a copper wire strand stripped of insulation were used as the second and third electrodes. The experimental vessel is docked in the commercial port of Petropavlovsk-Kamchatsky. The corrosion protection of the ship’s hull was evaluated by measuring the potentials between the metal hull and the reference electrode at a given point. The measurements were performed at a time interval from 06/10/2021 to 06/18/2021, evaluating the control of the hull corrosion protection was made by taking 50 successive measurements, which were entered into the control tables. It has been stated that the results of ship’s hull sacrificial protection control by using experimental copper electrodes from cabling comply with the regulatory requirements. The ship’s crew didn’t have any financial, organizational or technical problems, which could usually arise from the operation of standard silver chloride reference electrodes. It has been inferred that using regulated and non-regulated electrodes in the organization of corrosion control on ships and metal offshore structures is possible.

К вопросу использования алюминиевых электродов для контроля защищенности от коррозии стальных корпусов судов и кораблей

The article highlights the test results of a non-standard reference electrode made of a stripped of insulation strand of aluminum wiring, which were conducted on board an auxiliary marine vessel PM-15. The potential of the ship’s hull was measured at the same control point using three reference electrodes: silver chloride electrode No. 1; aluminum electrode No. 2; aluminum electrode No. 3. The vessel’s hull potential was measured over five days. All three reference electrodes were used daily. With the help of each electrode, fifty parallel measurements of the potential of the ship’s hull were carried out with a time interval between measurements of 5 seconds. To assess the accuracy of the measurement results, they were processed statistically. The factors that must be taken into account in the development of technologies for manufacturing non-standard reference electrodes are listed: using available inexpensive materials; avoiding expensive equipment in manufacturing the reference electrode; eliminating complex methods of storage of reference electrodes on ships. There has been given a diagram of measuring electrical circuits including the steel hull, a bulwark, a multimeter, a clamping device, switches, a silver chloride reference electrode, aluminum wires, etc. The results of the study can be used on sea-going vessels to organize the control of the protective effect of the hulls of ships and vessels in the absence of standard reference electrodes.

К вопросу использования цинковых электродов для контроля протекторной защиты судов и кораблей

The article focuses on the importance of organizing the ship operators training, who control the operation of systems protecting the sea vessels from corrosion. There are presented the results of a scientific research - control of the operation of the tread protection system of the steel hull of an auxiliary marine vessel (floating workshop PM-15), which is in a long-term standby mode. The potential difference between the ship's hull and two reference electrodes was measured at a given control point. The control measurements have been carried out using the reference electrodes: silver chloride reference electrode recommended for use by regulatory documents and zinc reference electrodes (not recommended by regulatory documents for sea vessels). There have been made 50 parallel control measurements. The time interval between parallel measurements was 5 seconds. Control measurements were performed within 5 days from 07.02.2020 to 07.14.2020. The accuracy of the control measurements was assessed in accordance with regulatory requirements. It has been stated that both reference electrodes provide high accuracy of control measurements; the results of control carried out with the help of zinc reference electrodes are highly stable. It has been inferred that zinc reference electrodes can be used on Russian ships to control the tread protection of the ship's hull and can be recommended for using by ship crews for training ship operators of ship corrosion protection systems.

Fluoride exposure and factors affecting dental caries in preschool children living in two areas with different natural levels of fluorides

BackgroundSuccessful oral health interventions must be based on the specific needs of the population that they serve. Evaluation of habits related to dental caries development and estimation of fluoride exposure in a target group of young patients helps to plan effective and safe caries prevention strategies. ObjectivesThe study aimed to evaluate factors affecting dental caries experience and sources of fluoride exposure in preschool children living in two areas: with optimal and low natural content of fluoride in drinking water. Materials and methodsThe study included a group of 73 children of both sexes aged 4–7 years attending two kindergartens in Środa Wielkopolska and Turek (Wielkopolska Voivodeship, Poland), where the content of fluoride in drinking water according to data obtained in the sanitary station ranged from 0.68 to 0.74 mg/L (optimal concentration of fluoride) and from 0.19 to 0.30 mg/L (low concentration of fluoride), respectively. Parents of patients completed a survey about diet, hygiene, and dental care, taking into account the child's fluoride exposure. The calibrated dentist assessed the oral health condition using a mirror, a CPI probe, and a headlamp. Oral hygiene was recorded using the Silness and Löe plaque index, caries experience by calculating the numbers of decayed, missing, and filled primary, and permanent teeth (dmf and DMF, respectively) while caries frequency by calculating the percentage of children with caries experience above 0. In order to assess the fluoride concentrations in urine and drinking water, parents were asked to provide a urine sample collected on fasting and a tap water sample. Fluoride concentrations were assessed using a 09–37 (MARAT) fluoride ion-selective electrode and a RAE 111 silver-chloride reference electrode. Statistical analysis was conducted using the data analysis software system Statistica (version 12, StatSoft, Inc. 2014), assuming a statistical significance level p < 0.05. ResultsNo statistically significant differences were found between caries indices of the examined children in each kindergarten (p > 0.05). Urinary fluoride levels were higher in children who tended to swallow toothpaste or used fluoride rinses and positively correlated with fluoride concentrations in the drinking water. Dental caries experience in the examined children depended on the effectiveness and frequency of oral hygiene procedures and dietary habits. ConclusionsThe strategy aimed at improving the oral health of the examined group of children should include accomplishing oral hygiene, promoting a non-cariogenic diet, and, finally, controlling fluoride exposure from at-home fluoride products. Caries prevention program ought to be adjusted to individual characteristics of each child, taking into consideration oral hygiene practices, dietary habits and total fluoride intake.

Electrodeposited Nickel-Iron Clusters Onto Glassy Carbon for the Detection of Methylene Blue

Methylene blue (MB) is a redox-active molecule, which is used for biochemical studies as a redox indicator,1-3 and as a comparable model for pyocyanin, a bacteria metabolite.4 Electrochemical detection of MB has been demonstrated through adsorption on gold electrodes,5 enhanced with a gold modified alkanethiol layer,5-7 and with carbon nanotube modified gold electrodes.8 In this study, a low-cost approach was used to develop a novel Ni-Fe/glassy carbon (GC) composite electrode to detect methylene blue. Ni-Fe microstructures were deposited from a sulfate-boric acid electrolyte at a pH of 3 by a pulse galvanostatic method. A three-electrode cell was used, containing a glassy carbon disk (GC) working electrode, a platinum counter electrode and a silver chloride reference electrode (Ag/AgCl). Deposition was carried out with and without electrode rotation. Field-emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray fluorescence analyzer (XRF) were used to characterize the surface morphology and the composition of the Ni-Fe clusters. The redox and adsorption behavior of MB were characterized with cyclic voltammetry and chronoamperometry/coulometry in a phosphate buffer solution (PBS) containing variable μM amounts of MB.The electrodeposition results showed interesting morphology and composition that impacted the MB electrochemistry, Fig. 1. The average composition of Ni-Fe clusters with a 2 s deposition time and without rotation was Ni-rich, 84 wt% Ni, 16 wt% Fe, and the morphology of the microscale clusters was composed of nanoscale nuclei in a circular shape with a hole in its center, attributed to gas evolution from the side reaction. The average size of the clusters was roughly 50 µm with different hole diameters (Fig. 1a). The average composition of Ni-Fe clusters with a 6 s deposition time and 400 rpm rotation rate had a contrasting composition, Fe-rich, 38 wt% Ni, 62 wt% Fe, and the morphology demonstrated microscale clusters with cracks. The average size of the microscale clusters was between 10 and 20 µm (Fig. 1b). The cyclic votammograms of the MB electrolyte, under quiescent conditions, were quasi-reversible, showing a single oxidation peak and a reduction peak. The Ni-Fe clusters impacted methylene blue (MB) chronoamperometry and coulometry, enhancing the response particularly for low concentrations of MB. Deviations from linearity in a plot of it1/2 vs. tunder reduction conditions, at a constant applied potential, indicated that the response was not diffusion controlled at times below 100 s, where the Ni-Fe/GC composite electrode had a significantly larger current signal, but with diffusion behavior observed at long times (Fig. 1c), with little to no improvement in the current in this region using the Ni-Fe/GC composite electrode compared to GC. The results show that the Ni-Fe/GC composite electrode can enhanced the electrochemical detection of MB at low MB concentration.AcknowledgementThe authors wish to thank H. Bilan at the Center of Advanced Materials Processing (CAMP) at Clarkson University for SEM help.References Y. Wu and R.Y. Lai, Analytical Chemistry, 86, 8888 (2014).W. Yang, R. Y. Lai, Langmuir, 27, 14669 (2011).L. E. Korshoj, A. J. Zaitouna, and R. Y. Lai, Analytical Chemistry 86, 8888 (2014).M. Kasozi, S. Gromer, H. Adler, K. Zocher, S. Rahlfs, S. Wittlin, K. Fritz-Wolf, R. H. Schirmer, and K. Becker, Redox Report, 16, 154 (2011).Sagara, H. Kawamura, and N. Nakashima, Langmuir, 12, 4253 (1996).Barou, M. Bouvet, O. Heintz, and R. Meunier-Prest, Electrochimica Acta, 75, 387-392 (2012).Zhao, B. Zeng, and D. Pang, Electroanalysis 15, 1060 (2003). García-González, A. Costa-García, and M.T. Fernández-Abedul, Sensors and Actuators B, 202, 129 (2014). Figure 1

Influence of the Corrosiveness of a Medium on the Ratio of the Cathodic Protection Current to the Ultimate Diffusion Current for KH70 Pipe Steel

We study the dependence of the ratio of the cathodic protection current to the ultimate diffusion current for Kh70 steel within the range of protective polarization potentials (-0.75)–(-1.05) V (relative to the silver-chloride reference electrode) standardized by the DSTU 4219 in media with different degrees of corrosiveness. It is shown that, within the рН range 5.6–9.6, as the potential shifts to more negative values, the ratio $$ {j}_{\mathrm{c}.\mathrm{p}.}/{j}_{{\mathrm{O}}_2} $$ increases from 0.5 to 138. It was discovered that, for the identical protective polarization potentials in a section of the gas main, the corrosion rate in a defect of the protective coating of steel may not only decrease but also activate the process of hydrogen reduction. It is reasonable to determine a value of the ratio $$ {j}_{\mathrm{c}.\mathrm{p}.}/{j}_{{\mathrm{O}}_2} $$ above which the process of decomposition of soil electrolytes is accelerated and the hydrogenation of the pipe wall in a defect of the coating becomes possible for every medium and take into account this value both in the design of the cathodic protection and in the process of monitoring in the course of operation to prevent stress-corrosion cracking.

Study of the effect of tensile stresses on hydrogen absorption upon cathodic protection of steel in sea water

When using cathodic protection of steel in sea water, hydrogen can be accumulated on the cathode surface and penetrate deep into the metal. This rather dangerous phenomenon of hydrogen corrosion can lead to hydrogen embrittlement, i.e., to destruction of the metal. We present the results of studying the impact of the temperature and external tensile stresses on the hydrogenation of cathodically protected steel in calm and mobile Baltic sea water. Dependence of the inhibitory hydrogenation on the temperature and applied load under the action of benzenesulfapyridine chloride as an inhibitor was analyzed. An MIP-102 machine (wire samples) and special equipment (half-ring and plate lamellar samples) were used to provide smooth control of the applied load set by the deflection and controlled by dynamometers (lamellar samples were tested under constant deformation). When studying the effect of temperature on steel hydrogenation, the working cell was thermostatically controlled. The wire and plate samples were polarized for 96 h, and half-ring samples for 1 h. The potential was measured with respect to the silver chloride reference electrode. The layered distribution of absorbed hydrogen in the metal was determined using anodic dissolution. It is shown that external tensile stresses increase the hydrogen content in the surface layers of steel. Hydrogen absorbed by a metal changes the potential of the steel surface (the more absorbed hydrogen, the stronger change). It is also shown that hydrogen is absorbed by the metal more actively in moving seawater than in calm water, and an increase in the load contributes to an increase in hydrogen content in the metal both in calm and mobile seawater. However, the load did not affect the hydrogen absorption with the inhibitor present, thus providing reduction of the hydrogen content in the metal under loading.

Sulfide ion Selective Method of Analysis of Sulfurated Hydrogen in Alkaline Smoked Cigarette Solution

Sulfurated hydrogen commonly called hydrogen sulfide (H2 S) is a clear, colorless, extremely toxic gas that has a rotten egg smell at low concentration. The human nose can detect H2 S at concentrations below 100 parts per billion (ppb). It is found least amount in cigarette smoke that has been the subject of analysis for many analytical chemists. This gases is soluble in alkaline medium and gives free sulfide (S-2 ) ions. Sulfide ion concentration in cigarette smoke solution is found in the range of detection limit of lab made Silver- silver sulfide (Ag/Ag2 S) ion selective electrode (ISE).This project has designed to investigate the amount hydrogen sulfide as a free sulfide (S--)ion in cigarette smoke solution. Silver-silver sulfide ion selective electrode (Ag/ Ag2 S ISE) and Silver–silver chloride (Ag/AgCl) reference electrode are prepared in the lab for determination. Detail protocol of standard addition method with modified Grant’s plot is applied for estimation. Different brand of cigarette samples were collected from different area of Pokhara valley and analyzed. The average amount of H2 S per stick of cigarette smoke is found to vary from 0.0453 mg to 0.0573 mg in different brands. Among them sample no SA-5 shows 0.0453mg per stick of cigarette. This result is minimum in compare to other brands. Similarly, sample no SA- 7 have found 0.0573mg per stick which is higher in compare to other brands.&#x0D; Key words: Cigarette smoke, hydrogen sulfide, ion selective electrode, standard addition method, Grant’s plot method,

О выборе электродов для контроля систем протекторной защиты стальных судов и кораблей

The article considers the problems of ship structures exposed to adverse conditions, which contribute to the failure of important mechanisms and reduce the service life of steel parts &#x0D; of machines. One of the most important reasons for the ship structures wear is corrosion. The experience of choosing the electrodes to control the sacrificial protection systems on board ships is presented. There are presented the results of measuring the potential of the hull of the boat ROOM 52-22 at a given control point, using a multimeter MASTECH MY 62 and two control electrodes. The first control electrode is of in-house design; it was made of electric carbon product for electric machines. A standard portable silver chloride reference electrode was used as a second electrode. Both electrodes have been in operation for 3 years. The vessel under consideration was in a long-term parking mode. Control measurements were performed from 23.05 - 07.07.2019, while monitoring the potential of the hull three times a day using several parallel measurements. The time interval between parallel potential measurements made ≈ 5 seconds. The potential of the hull was measured by a specially trained operator. The accuracy of measurements was estimated using the coefficient of variation. Analysis of the studies justified that the accuracy of the control results of the protective anticorrosion systems on ships depends on the choice of the type of control electrode. It has been found that the efficiency of the silver chloride electrode has a strong impact on its operation life. The results of full-scale corrosion studies can be used by ship crews to justify the selection &#x0D; of control electrodes.