Calculated Corrosion Rates Research Articles

Effect of Corrosion Inhibitors Admixtures on Corrosion Rate of Steel Reinforcement in Concrete (Dept.C)

Reinforcement corrosion is the main cause of damage and early failure of reinforced concrete structures. The protection system of embedded steel reinforcement from chloride induced corrosion involves several methods and techniques. One of these methods and techniques is using corrosion inhibitors admixtures (CIA) which added to concrete mix during mixing stage of concrete. These research aims to evaluate these admixtures (Sika Ferrogard®-901) in prevent corrosion of steel in concrete and their effect on concrete properties for fresh and hardened concrete. In this paper (CIA) used with different concrete contents and proportions. In this study, 150-mm concrete cubes specimens with high tensile steel bar grade (36/52) of 10 mm in diameter and 150 mm in length were embedded in each specimen during its casting such that 100 mm was fixed inside the concrete while the reminder 50 mm was kept outside. Three thicknesses of concrete cover were used; 25, 50 and 75 mm. After 28 days of water curing, specimens were transferred to dry for 24 hour, then the specimens were partially submerged in plastic tank filled with 6% NaCl solution Acceleration of corrosion rate test is achieved by continuous electrical current produced from power supply 30 volts for 240 hour, where volts difference was measured in volts between resistance 100 ohm and the reading was record every 12 hour. The corrosion current (Icon in Ampere) was calculated during the accelerated corrosion regime by using ohm's law by knowing measured volts difference and resistance. Faraday's law describes the relationship between section loss and corrosion current. Hence, calculate corrosion rate of steel reinforcement in concrete. The results show that for all mixes the increasing of concrete cover thickness reduces the corrosion rate of steel. Using 5% (CIA) by weight of cement where the optimum dosage of Corrosion inhibitors admixture from experimental tests is 5% by weight of cement reduce corrosion rate by 80 % with no side effect on concrete properties except bond strength decreased by 10%.(CIA) gave best results with concrete mixes which contains 15% silica fume and water to cement ratio 0.35 · (CIA) decreasing concrete cover required to prevent corrosion from 75 mm to 50 mm. (CIA) accelerate setting time of concrete, so it needs a retarded when used with concrete mixes.

Electrochemical Analysis and In Vitro Assay of Mg-0.5Ca-xY Biodegradable Alloys.

In recent years, biodegradable Mg-based materials have been increasingly studied to be used in the medical industry and beyond. A way to improve biodegradability rate in sync with the healing process of the natural human bone is to alloy Mg with other biocompatible elements. The aim of this research was to improve biodegradability rate and biocompatibility of Mg-0.5Ca alloy through addition of Y in 0.5/1.0/1.5/2.0/3.0wt.%. To characterize the chemical composition and microstructure of experimental Mg alloys, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), light microscopy (LM), and X-ray diffraction (XRD) were used. The linear polarization resistance (LPR) method was used to calculate corrosion rate as a measure of biodegradability rate. The cytocompatibility was evaluated by MTT assay (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) and fluorescence microscopy. Depending on chemical composition, the dendritic α-Mg solid solution, as well as lamellar Mg2Ca and Mg24Y5 intermetallic compounds were found. The lower biodegradability rates were found for Mg-0.5Ca-2.0Y and Mg-0.5Ca-3.0Y which have correlated with values of cell viability. The addition of 2–3 wt.%Y in the Mg-0.5Ca alloy improved both the biodegradability rate and cytocompatibility behavior.

High-Temperature Corrosion of Copper Induced by TeO2

It was found that copper is susceptible to the accelerated high-temperature corrosion induced by TeO2 at 650°C in air, which occurs at a constant rate. The calculated corrosion rate constant is 4.5 × 10−4 kg·m−2·s−1 and does not depend on the specific mass of tellurium oxide. Based on the results of the analysis of the microstructure (scanning electron microscopy/energy dispersive x-ray spectroscopy) and the phase composition (x-ray diffraction) of two formed corrosion layers, the phase distribution in the corrosion product has been ascertained. It was shown that during the corrosion process at 650°С, the inner corrosion layer containing Cu2O and Cu2Te and the outer corrosion layer mainly containing CuTe2O5 and Cu2O were formed. The inner layer provides a high copper ion conductivity due to Cu2Te, while the outer layer possesses a high oxygen ion conductivity due to the oxide melt. The mechanism of the overall corrosion process has been proposed.

Experimental study of corrosion rate on st60 steel as a result of immersion in HCl, NaOH, and NaCl solutions

The purpose of this study is to calculate corrosion rate (CR) of ST60 steel. A wet corrosion test was conducted by dipping ST60 steel in the solution of HCl, NaOH, NaCl. Use weight loss Method to calculate CR. It was found that the highest corrosion rate occured when the specimen of ST60 steel dipped on HCl0.1M solution. Corrosion that occurs for all corrosion tests is immersion in HCl, NaOH, and NaCl solutions produces uniform corrosion

Protection of fuel filter with alkaline and acid zinc coatings

Galvanic coatings are applied so that the surface of the base material obtains appropriate properties, corrosion resistance, durability, aesthetic appearance, and long-term application in the appropriate industry. In this paper, the aim was to protect steel fuel filters with alkaline and acid zinc coatings of different thicknesses. The coating of zinc, which is applied from the alkaline electrolyte, provides good corrosion protection with excellent coating flexibility. The thickness of the coating by the X-ray fluorescence method was tested, followed by coating tests, corrosion resistance, and electrochemical tests. The results of adhesion showed a high quality coating, as no corrosion occurred during the test. The corrosion resistance tested by the salt chamber method speaks of the appearance of white and red corrosion. On alkaline electrolyte coatings, white corrosion occurred after 168 hours of exposure to the salt test, while on white zinc samples there was a white corrosion after 240 hours of exposure. Tafel polarization diagrams have been determined: corrosion potentials, current intensities, anode and cathode Tafel coefficients and calculated corrosion rates. The active and passive corrosion zone is determined by the cyclic voltammetry.

A study of corrosion enhanced erosion in Nickel Aluminium Bronze with Niobium and Yttrium

An investigation was carried in Nickel Aluminium Bronze (NAB) alloyed with Niobium (Nb) and Yttrium (Y) to study the effect of the microstructure for onshore applications. Nickel Aluminium Bronze is broadly used in aqueous atmospheres due to their good mechanical and corrosion resistance properties. The presence of destructive species in aqueous water initiates the corrosion of the engineering modules is inevitable. In-order to optimize the corrosion resistance Nb and Y were added as (1%, 2% & 3%) respectively in the master NAB. The specimens were exposed to the immersion test in NaCl solution. To create the behavior of corrosion and succeeding erosion, altered immersions hours were selected as 8, 16, 24, 32, 40, 48 and 54 h. The mass loss measurements were obtained after the completion of the individual specified time to calculate corrosion rates (CR). Solid particle erosion (SPE) investigations were also carried out on the developed alloys. The size of the particle which is used in the investigation is 50 µm. Corrosion rate was calculated and it is correlated with the immersion time. Scanning electron microscopy (SEM) investigations were observed for the corroded and eroded specimens.

Advanced Electrochemical Sensors for Monitoring Relative Humidity and Internal Corrosion Rates of Natural Gas Transmission Pipelines Containing H2s

Monitoring the internal corrosion of natural gas transmission lines is required for safe management of natural gas infrastructures. Internal corrosion programs can be strengthened by real-time monitoring of key risk factors such as relative humidity and corrosion rates of the pipeline material. We have developed a membrane-based electrochemical sensor, which functions in gaseous environments, to provide this real-time monitoring capability. The design is based on the sensitivity of the membrane’s conductivity to gaseous water content. We match relative humidity curves to 4-electrode, electrochemical impedance spectroscopy results, and use 3-electrode, linear polarization resistance tests to calculate corrosion rates. Due to the membrane’s atypical current pathways, precise estimation of the sensor’s cell constant was required to interpret the impedance results into relative humidity. We utilize finite-element analysis to obtain our cell constant (14.84 cm-1), and the resulting membrane conductivity values were in good agreement with published data. The sensor was tested in H2S environments to gauge how these results may change with acidic gases that may be present in the natural gas stream.

Effect of Hydrogen Embrittlement on the Mechanical and Electrochemical Properties of Carbon Steel API 5L X65 in a CO2-Saturated 3.5 Wt.% NaCl Solution

The effect of hydrogen charging of carbon steel API 5L X65 (UNS K03014) used in natural gas pipelines was investigated. Metal specimens were cathodically charged at potentials below Ecorr at 40°C in CO2-saturated 3.5 wt.% NaCl solution, pH 4 for 24 hours prior to carrying out potentiodynamic polarization and tensile tests. Electrochemical experiments were used to calculate corrosion rates and elucidate active, active-passive, and passive regions. Furthermore, fracture and fatigue of the alloy was determined at 1 × 10−6 s−1 strain rate. Surface characterization of the fractured and corroded samples was conducted using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Results from hydrogen embrittlement-induced specimens were compared to a parallel study of uncharged specimens to understand the effect of hydrogen cathodic charging on carbon steel API 5L X65.

Discussion on the relationship between iron content and corrosion rate in production fluid of oil wells

To provide an economical and practical technique for the application of on-line corrosion monitoring technology in oil production system, in this paper, the iron content was measured by a water quality multi-parameter tester and corrosion rate was determined by the weight loss method. Then, the quantitative relationship between the iron ion and corrosion rate could be found. On this foundation, in order to correctly describe the corrosion in the wellbore of oil wells, according to SY/T0026-1999 water corrosion test method standards, a mathematical relational expression between iron ion content and corrosion rate in oil wells production fluid was established. In order to verify the reliability of relational expression, the iron content in the produced fluid of 17 wells corrosion conditions before and after adding medicine were measured on the spot. Then, the relational expression entered the field application. The results show that there was the positive correlation between the iron ion and corrosion rate. The error of the calculated corrosion rate of 17 wells in the field was less than 26% compared with the measured corrosion rate. The mathematical relational expression had good effect in J45-62 well. It could reflect the corrosion trend of well bore. Thus, through the internet+ technology, the on-line monitoring system for remote corrosion could be established, and corrosion trend of wellbore pipelines could be predicted with the help of nerve net algorithm.

Hybrid anode concrete corrosion protection – independent study

This study was the first of its kind to investigate the long-term performance of hybrid anode systems in reinforced concrete as part of a holistic approach to corrosion risk assessment. An independent appraisal of the site performance of hybrid anode corrosion protection systems (UK invention disclosed in Patent GB2426008B) was conducted on six bridge structures in 2014. The aim of the study was to investigate the effectiveness of current design approaches in meeting the residual service life when the anodes are operating in the galvanic phase. This was achieved by analysing data on the general condition of the structures, studying the ongoing performance of the installed hybrid anodes and assessing the overall corrosion risk. It was found that the six structures were generally in good condition, with low associated corrosion risk in areas protected by the hybrid anode systems. This is a positive finding for the wider implementation of hybrid anode systems as an alternative corrosion management technique. The reinforcement in the protected areas remained predominately in a passive condition, with calculated corrosion rates below the ISO 12696:2012 recommended threshold of 2 mA/m2. Recommendations regarding design are provided in order to improve the redundancy, functionality and robustness of hybrid anode systems.

Sensitive analysis of calculation of corrosion rate according to standard approach

There is a lot of factors, which may affect the reliability of the construction, as durability, serviceability and safety of construction or its parts elements. Corrosion damage either reinforcement is one of the most important factor in reinforced concrete structures or structures made from structural steel. This corrosion damage can be determined by actual standard EN ISO 9223. This standard describe the equations, called dose-response functions, for calculation of the corrosion rate rcorr for standard materials like carbon steel, zinc and so on. These equations are determined from the corrosion rate of samples under outdoor atmospheric corrosion in cooperating with measuring of climatic data. Input parameters on calculation of the dose-response functions are sulphur dioxide, temperature, relative humidity and chloride ions. This article is focused on the calculation of the carbon steel corrosion rate according the dose-response function and its sensitive analysis for various concentration of the input parameters. This variability of the input parameters may represents the different conditions, in which the constructions may appears. In practice, this information may provide, which of the input parameter influence the most the calculated corrosion rate and if it is needed to more concentrate its measuring station network. The location of the outdoor stations with the specimens or choice of accelerated corrosion test may be also provided.

Electrochemical impedance spectroscopy of iron corrosion in H2S solutions

Corrosion of iron exposed to H2S saturated solution at pH 4 was studied by electrochemical impedance spectroscopy, weight loss coupons and surface analysis. Hydrogen permeation was also used as indirect means of evaluating the intensity of the proton reduction reaction leading to hydrogen entry into the metal.Since corrosion in this type of test solution results in the rapid build-up of a conductive and highly porous iron sulfide scale, a specific contribution of the film has to be considered. An impedance model was thus proposed. The faradaic anodic impedance consists of a two-step reaction with charge transfer and adsorption – desorption. An additional contribution, associated with the conductive and highly porous iron sulfide film was added in parallel. This contribution, mostly visible in the low frequency domain, presents a 45° tail associated with a porous electrode behavior. This model was well adapted to describe impedance diagrams measured at various exposure times, up to 620 h. Charge transfer resistance determined from impedance analysis allowed calculating the evolution with time of the corrosion current density. A very good correlation was found between this corrosion current density and the hydrogen permeation current density. As expected in our experimental conditions, a permeation efficiency close to 100% is demonstrated. Corrosion rate of 490 μm/year was measured by weight-loss specimens, confirming the validity of the impedance analysis, which resulted in a calculated corrosion rate of 530 μm/year.

System for corrosion monitoring in pipeline applying fuzzy logic mathematics

A list of factors influencing corrosion rate on the external side of underground pipeline is determined. Principles of constructing a corrosion monitoring system are described; the system performance algorithm and program are elaborated. A comparative analysis of methods for calculating corrosion rate is undertaken. Fuzzy logic mathematics is applied to reduce calculations while considering a wider range of corrosion factors.

Corrosion Prediction for Corrosion Rate of Carbon Steel in Oil and Gas Environment: A Review

Corrosion predictions are essential for corrosion and material engineers. It is used to prepare pre-Front End Engineering Design (pre-FEED). FEED guides to select appropriate materials, planning test schedule, work over management, and estimate future repair for cost analyses. Corrosion predictions also calculate life of pipeline and equipment systems during operational stages. As oil and gas environments are corrosive for carbon steel, it is important to account the corrosion rate of carbon steels in those environmental conditions. There are many existing corrosion predictions software, which are available in oil and gas industries. However, corrosion predictions only can be used for particular ranges of environmental conditions because they use different input parameters. To select the most applicable of corrosion predictions software, engineers have to understand theoretical background and fundamental concept of the software. This paper reviews the applications of existing corrosion prediction software in calculating corrosion rate of carbon steel in oil and gas environmental systems. The concept philosophy of software is discussed. Parameters used and range of conditions are also studied. From the results of studies, there are limitations and beneficial impacts in using corrosion software. Engineers should understand the fundamental theories of the corrosion mechanism. Knowing limitations of the models, the appropriate model can be correctly selected and interpretation of corrosion rate will close to the real data conditions.

Effect of zinc precursors on the hydrogen evolution reaction and electrochemical corrosion studies of ZnWO4 nanoparticles synthesized by hot injection method

ZnWO4 nanoparticles were synthesized by a hot injection method using different zinc precursors (zinc nitrate, zinc acetate, zinc sulphate and zinc chloride) with sodium tungstate. Similarly, the ZnWO4 particles were prepared by co-precipitation and solid-state method for comparative analysis. The phase formation temperature of ZnWO4 was identified through thermal analysis. X-Ray diffraction (XRD) analysis enumerates that the formation of a single-phase monoclinic wolframite structure with the space group P2/c. The characteristic functional groups of Zn-O, Zn-O-W, and W-O were identified through Fourier Transform Infrared Spectroscopy (FTIR). The microscopic images revealed that the formation of spherical shape particles in size range between 60 and 100 nm. The room temperature electrical conductivity was measured using LCR meter, and it shows that the conductivity is in the range of 2.2 × 10−5 to 6.2 × 10−6 S.cm−1. The calculated corrosion rate of ZnWO4 using Tafel Polarization curve in 1 M H2SO4 at 1 mV s−1 was 0.2554 mmpy. The electrocatalytic activity towards the hydrogen evolution reaction (HER) was studied using linear sweep voltammogram in 1 M H2SO4 solution at a scan rate of 1 mV s−1. Further, the zinc acetate precursor assisted particles have shown a low onset potential (0.42 V) and higher current density (−228.52 mA cm−2) in the potential range of 0 to −1.0 V compared with other samples.

PEMANFAATAN SAKARIN SEBAGAI ALTERNATIF PENGENDALI KOROSI BALING-BALING KAPAL

Corrosion is a metallic interaction with the environment that causes damage to the metal. Corrosion can also occur in fishing vessels, which are generally made of low carbon steel. This happens because the propeller works in a corrosive environment. Then the need for an alternative corrosion control so that the component is durable. The purpose of this study was to find out how much corrosion rate the ship propellers produced after the addition of saccharin on the nickel electroplating process. This study was conducted by specimen electroplating nickel with the addition of saccharin variation of (0.6 gram; 0.8 gram; and 1 gram). Then the results in corrosion test using sea water media. The corrosion rate is calculated using the weight loss method. After the calculated corrosion rate, then the effectiveness of saccharin is calculated. The results showed that nickel electroplating specimens with addition of 0.6 gram saccharin variation resulted in a corrosion rate of 75 mpy, 0.8 gram saccharin yielded a corrosion rate of 83.14 mpy, saccharin 1 gram of corrosion rate of 90.56 mpy, while raw material corrosion rate of 117.73 mpy.

Long-Term Performance of Hybrid Anodes for Cathodic Protection of Reinforced Concrete

The long-term performance of hybrid anode corrosion protection systems (UK invention disclosed in Patent GB2426008B) was investigated on six bridge structures as part of a holistic approach to corrosion risk management, using the performance criteria in ISO BS EN 12696:2016. The aim of the study was to review the effectiveness of current design approaches to meet the residual service life when the anodes are operating in the galvanic phase. This was achieved by analysing data on the general condition of the structures, the ongoing performance of the installed hybrid anodes, and assessing the subsequent corrosion risk. It was found that the six structures were generally in good condition, 1 to 8 years after refurbishment works, with low associated corrosion risk in areas protected by the hybrid anode systems. This is a positive finding for the wider implementation of hybrid anode systems as an alternative corrosion management technique. The reinforcement in the protected areas remained predominately in a passive condition, with calculated corrosion rates below the ISO 12696:2016 recommended threshold of 2mA/m2.

Rollinia occidentalis extract as green corrosion inhibitor for carbon steel in HCl solution

An extract of Rollinia occidentalis as well as pure solutions of two acetogenins isolated from this extract, namely Rolliniastatin-1 and Motrilin, were tested as corrosion inhibitors for carbon steel in acidic solutions. Weight loss measurements were performed in the 298–328K temperature range and the obtained data were used to calculate corrosion rate and inhibition efficiency. It was found that the extract and the acetogenins solutions act as good corrosion inhibitors for the tested C-steel in 1M HCl media. Moreover, results from potentiodynamic polarization measurements indicate that R. occidentalis and the two tested acetogenins act as mixed-type inhibitors. Data collected from EIS studies were modeled with an equivalent circuit containing a single time constant what can be understood in terms of a corrosion inhibition process resulting from the geometric blocking effect of the carbon steel surface by an adsorbed inhibitor species. Inhibitor adsorption follows a Langmuir adsorption isotherm. The inhibition efficiency decreases with increasing temperature and extract concentration. Spectroscopic analysis points to the formation of a complex between metal cations and compounds present in the R. occidentalis extract. This additional aspect is considered in the proposed inhibition mechanism of C-steel.

Relationship Between pH and Electrochemical Corrosion Behavior of Thermal-Sprayed Ni-Al-Coated Q235 Steel in Simulated Soil Solutions

Electrochemical corrosion behavior of a thermal-sprayed Ni-Al-coated Q235 steel was investigated in the simulated soil solutions at different pH values using measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy as well as surface analyses including x-ray diffraction analysis, scanning electron microscope equipped with an energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The results showed that the corrosion resistance of the Ni-Al-coated Q235 steel was dependent on the pH of the test solution. From pH = 3.53 to pH = 4.79, the corrosion resistance of the coated steel increased rapidly. In the pH range from 4.79 to 12.26, the corrosion resistance exhibited no significant change. At pH 13.25, the corrosion resistance of the sample was found to decrease. The calculated corrosion rate of Ni-Al-coated Q235 steel was lower than that of the uncoated Q235 steel and galvanized steel in all the test solutions. Over a wide range of pH values, the Ni-Al-coated Q235 steel exhibited extremely good corrosion resistance. The experimental data together with the potential-pH diagrams provided a basis for a detailed discussion of the related corrosion mechanisms of the coated steel.

Time evolution of Electrochemical Impedance spectra of cathodically protected steel in artificial seawater

Usability of Electrochemical Impedance Spectroscopy data for better cathodic protection control was investigated. Carbon steel – S235JR2 grade specimen were exposed in artificial seawater environment. Samples were polarized and their potentials corresponded to four different cathodic protection degrees. Time evolution of Electrochemical Impedance spectra was investigated. Goodness of fit function (X2) was analysed in terms of proper time-constant quantity determination. It was possible to observe and detect occurrence of new phenomena by X2 evaluation. Weight-loss corrosion coupons were used to calculate corrosion rates. At initial stage of exposition impedance measurements complemented proper protection potential data. Quantity of physical and electrochemical processes was evaluated and linked to the state of specimen providing valuable supplementary data. EIS proved to be useful for hydrogen evolution detection which is a great risk which has to be recognised and prevented.