Corrosion Rate Values Research Articles

Performance of Corrosion Behavior of Commercial Magnesium Alloy Anode Electrode in Seawater-Powered Lamps

In modern times, alternative technologies that are efficient and environmentally friendly continue to be developed, such as lamps fueled by seawater. By reacting between a magnesium alloy anode electrode and an electrolyte solution of salt, a difference in electrical potential is generated, which can power electronic equipment. In order to achieve optimal performance with the magnesium alloy anode electrode, an initial assessment of this component is necessary. This research discusses the corrosion behavior of the magnesium alloy anode electrode caused by variations in salinity in seawater batteries. In this study, five samples of commercial product anode electrodes were prepared. Each sample was immersed in a salt solution with different salt concentrations. The salt solution was prepared by mixing 380 ml of distilled water with salt masses of 14g, 16g, 18g, 20g, and 22g respectively. Potentiodynamic testing was conducted in this research. The results showed that the corrosion behavior produced from the five samples yielded the highest corrosion potential, electrical current, and corrosion rate values of (Ecorr = 1.5419 Volts), (Icorr = 0.0010 Amps/cm2), and 12.5850 mm/a, respectively. These results indicate an increase in corrosion rate with increasing salinity. It is hoped that in future research, additional treatments will be applied to the electrode to achieve better performance.

A Case Study: Investigation of Untreated and Treated 304 Stainless Steel on Corrosion Behaviour

A titanium coating on an iron-based metal surface significantly enhanced its resistance to localised corrosion. The research thoroughly investigated the microstructure and corrosion behaviour of both the untreated and treated 304 stainless steel substrates. The coating’s morphology was meticulously examined using scanning electron microscopy (SEM), while its chemical composition was determined via energy-dispersive X-ray spectroscopy (EDX). Electrochemical impedance spectroscopy (EIS) was employed in an open circuit potential experiment to evaluate the coating’s resistance to localised corrosion in an alkaline solution. SEM was again utilised to assess the coating’s morphologies and cross-sectional view. The result revealed that untreated samples showed small and large pits on the microstructure, while no pit was detected in treated samples. Only fine dimples and voids were observed for the treated sample. The treated sample exhibited superior corrosion resistance to the untreated sample with a corrosion rate of 0.002348 mm/year and 0.007109 mm/year, respectively. This is attributed to the presence of the coating for a treated sample with curing for 10 minutes. The corrosion rate value is still considered excellent and accepted for stainless steel because the corrosion rate penetration is below 1 mils per year (mpy).

Determination of Optimal Corrosion Logging Frequencies for Gas Storage Fields

Summary Many of the existing wells in underground natural gas storage facilities were originally designed to extract hydrocarbons, using construction techniques and practices that differ from modern storage well drilling and completion practices used today. In addition to the age of these wells, their primary flow strings and tubulars may have been exposed to naturally occurring corrosive environments that could have degraded their wall thickness and remaining burst strength. This presents a serious risk of well failure and loss of containment for both the wells and reservoirs of these fields. To address this issue, the Pipelines and Hazardous Materials Safety Administration in its interim final rule recommended that all operators of gas storage facilities determine the reassessment intervals required to maintain the pressure rating and flow isolation properties of the flow string of all gas storage wells. This work presents a novel methodology for establishing the optimal logging frequencies required to maintain the integrity casing wall thickness of the primary flow string, which serves as the leading indicator of casing integrity. In this study, metal loss data from magnetic flux-leakage logs run on existing gas storage wells are collected, vetted, and used to derive a probabilistic distribution of linear corrosion rates. Statistical values of corrosion rate corresponding to severity levels are used to approximate the corrosion rate distribution, allowing for deterministic prediction of remaining burst strength with suitable failure criterion models. The modified ASME B31G model is used to predict casing remaining life as a function of metal loss class and average corrosion rate (ACR). The reliability criterion for establishing fitness-for-service of a corroded casing string is evaluated separately using Monte-Carlo simulation, while reassessment intervals corresponding to a particular casing condition are calculated deterministically. The modeling results with the new approach present predictions of remaining life for four commonly used casing strings as a function of metal loss class and ACR. The results show that the remaining life of a corroded casing can be reasonably estimated as a function of static corrosion rate and metal loss class. The most significant finding is that a brand-new well with an average annual corrosion rate of 1.0% initiating instantaneously upon installation will have an estimated remaining life of 28–32 years. Reassessment intervals are defined based on casing half-life as a function of metal loss class and ACR. A field case study is also presented to demonstrate the successful application of the new methodology in predicting reassessment frequency to mitigate risks from external corrosion mechanisms. The novelty of the proposed approach is in the ability to reasonably predict casing remaining life and safety target levels using derived statistical distributions of linear corrosion rates calculated from magnetic flux leakage logs. This in turn allows operators to confidently establish reassessment intervals for future casing inspection logging to identify corrosion threats in a timely manner that achieves a balance of risk mitigation and cost savings.

Composite coatings from polycarbosilane derived SiC and Al/SiC cermet active fillers as protective barriers against steel corrosion

Stainless steel is used throughout the world as a structural material. However, it undergoes corrosion damage when exposed to extremely corrosive media, such as the marine environment. An alternative to solve this problem lies in the development of coatings that can withstand extreme conditions but also be easily deposited with inherently corrosion-resistant materials such as silicon carbide (SiC). The present study shows a simple method to produce Al/SiC cermet powders by attrition milling. The resulting cermet powders with a metallic matrix and hemispherical morphology, were employed as fillers in polycarbosilane (PCS) solutions that were sprayed on A304 stainless steel substrates. Al/SiC composite coatings were produced after heating the sprayed suspensions at 700 °C for 1 h in Ar atmosphere. The resulting composite coatings exhibited low surface energies (< 35 mN/m), water contact angles of 53°, and adhesion strength of up to 30 MPa. Finally, corrosion tests were performed in a cyclic corrosion test chamber, showing that these coatings effectively reduced the corrosion rate of stainless steel by 87%, reaching corrosion rate values of 0.007 g/cm2 year.

Evaluation of Passive Films on 17-7PH and 410 Stainless Steel Exposed to NaCl Solution.

This work covers the formation of a passive state for two different alloys used in the aeronautical industry. The aim of this study is to investigate the effectiveness of passivation treatments on 17-7PH and 410 SS (stainless steel) samples, specifically when performed with citric and nitric acid solutions at 49 °C using an immersion time of 90 min and subsequent exposure in 3.5 wt.% NaCl solution. Employing the cyclic potentiodynamic polarization (CPP) technique, the corrosion properties of the passivated material were evaluated according to the ASTM G65-11 standard. A microstructural analysis was performed using scanning electron microscopy (SEM). The passivated layer was characterized via X-ray photoelectron spectroscopy. In the results, the CPP curves showed positive hysteresis, indicating pitting localized corrosion, and 17-7PH steel passivated at 49 °C for 90 min in citric acid exhibited lower corrosion rate values equivalent to ×10-3 mm/year.

Production and characterization of low-density silicon nitride reinforced zinc nanocomposite coatings on mild steel for applications in marine and automotive industries

In today's automotive, marine and petrochemical industries, the desire for lightweight materials has increased. Hence, necessitating the production of components with low density. In this work, lightweight Zn–Si3N4 coatings were developed by including Si3N4 in the zinc matrix. The optimal coatings were produced on steel samples at 45 °C and varied Si3N4 particles and voltages following ASTM A53/A53M standard. The deterioration (corrosion) property i.e. corrosion rate (CR) and current density (jocorr) of the uncoated (control) and coated samples were examined in 0.5 M of sulphuric acid using a potentiodynamic polarization technique following ASTM G3/G102 standard. The microstructure of the samples was studied via the SEM micrographs and XRD patterns, while the wear performance resistance (following ASTM G99 standard) and electrical conductivity of the samples were examined with a pin-on-disc tribometer and ammeter-voltmeter. The corrosion experiment indicated that the uncoated mild steel specimen possessed a CR of 12.345 mm year−1 and jocorr of 1060 μA/cm2, while the CR and jcorr of the coated samples ranged from 2.6793 to 4.7975 mm year−1 and 231−413 μA/cm2, respectively. The lower CR and jcorr values of the coated specimens, relative to the coated sample showed that the coatings possessed superior passivation ability in the test medium. The SEM micrographs of the samples showed refined morphology, while the XRD patterns revealed high peak intensity crystals such as Zn4SiN, ZnNSi, Zn4N and Zn2NSi, which could be beneficial to the mechanical properties and corrosion resistance of the steel. Moreover, the wear resistance study indicated that the COF of the uncoated sample ranged from 0.1 to 0.5, while those for coated specimens ranged from 0.05 to 0.35. Similarly, the uncoated steel exhibited a wear volume (WV) of 0.00508 mm3, while the WV of the coated specimens ranged from 0.00266 to 0.0028 mm3, indicating the existence of high strengthening mechanisms between the interface of the protecting device and the steel. Also, the electrical conductivity of the mild steel sample reduced from 12.97 Ω−1cm−1 to 0.64 Ω−1cm−1, indicating that the electrical resistivity of the steel was enhanced by the coatings.

Strategic Development of Ni–Cu–Fe2O3 Composite Coatings to Strengthen Mild Steel Against Corrosion

Mild steel is extensively employed in various industries due to its affordability and versatility. However, its susceptibility to corrosion poses a significant challenge. This study explores the efficacy of protecting mild steel by applying coatings composed of highly noble copper and its alloys. In this direction, Ni–Cu alloy and Ni–Cu–Fe2O3 coating have been developed from a sulfate citrate bath on mild steel through the electrodeposition method. The alloy and composite coating deposition was done at different current densities 1 A dm−2, 2 A dm−2, 3 A dm−2, and 4 A dm−2. The copper content of the coating has increased with an increase in current density in both alloy and composite coatings. The deposit with a high Copper content showed lower crystallite size with a lower corrosion rate value at a current density of 3 A dm−2. The trace addition of Fe2O3 into the Ni–Cu alloy matrix has improved the overall corrosion resistance of the mild steel materials as compared to bare Ni–Cu alloy coating.

In Vitro and In Vivo Degradation of the New Dissolvable Surgical Wire, Produced from Zn Based Low Alloy by Hot and Cold Drawing

The biocorrosion of a new surgical wire (0.6, 0.8, and 1.0 mm in diameter) obtained from a ZnMg0.004 alloy by hot and cold drawing was characterized using in vitro tests in a bovine animal serum solution and in vivo tests – through placement in the muscles of a rabbit and a in cat's broken paw. Corrosion gravimetric tests were carried out in a corrosive environment refreshed every 3 days and also one which remained unchanged throughout the test period. Electrochemical tests were performed in the same solution of serum as in gravimetric tests. Depending on the initial diameter, complete dissolution of the wire was observed after 36-78 days of immersion in periodically changed serum solution. None of the wires completely dissolved over 120 days in the unreplaced serum solution. The corrosion rate values determined in electrochemical and gravimetric tests were similar. After 90 days of in vivo tests, both in the body of the rabbit and the cat, the degradation of the wire was similar to in vitro tests in the unreplaced serum solution. No harmful effects were observed in the animals.

Microstructure and properties of WC-reinforced AlCoCrFeNiSi high entropy alloy coatings prepared via high-velocity arc spraying

In this research, (AlCoCrFeNiSi)100-x(WC)x (x=0, 20 and 40 wt%) high entropy alloy (HEA) coatings were successfully deposited on the surface of Q235 steel substrate using high-velocity arc spraying method. The study investigated the presence of WC particles on the phase composition, microstructure, tensile bonding strength, and corrosion behavior of the HEA coatings. X-ray diffraction analysis revealed that without WC particles, the predominant phase in the coating was a face-centered cubic (FCC). However, when 20 wt% and 40 wt% of WC particles were added, the phase composition shifted to include FCC, body-centered cubic (BCC), W3C, Cr7C3, and other carbides. The WC particles also reduced the crystalline grain size of the coatings from 14.75 nm to 10.34 nm. The microhardness value increased from 252.5 HV0.1 to a peak of 529.9 HV0.1, as the content of WC increased representing a microhardness improvement factor ranging from 1.4 to 3 times that of the substrate. The tensile bonding strength of the coatings was also enhanced with WC content. The coating with 40 wt% WC particles demonstrated the highest tensile bonding strength of 40.23 MPa. The cohesion, adhesion, and glue failures occurred after the tensile test, with adhesion failure being more prominent in the coatings without WC particles and glue failure being more prominent in the WC-reinforced coatings. Compared to the Q235 steel substrate, the coated samples showed enhanced resistance against corrosion due to the formation of the passive oxide layers. The effective resistance against corrosion was attained when the proportion of WC particles was 20 wt%, displaying the least values for corrosion current density and corrosion rate in 3.5 wt% NaCl solution. Examination through SEM and XPS analysis indicated that the coatings’ structures and the formation of protective passive layers enhanced the corrosion resistance.

Karakterisasi Tebal Lapisan Dan Ketahanan Korosi Mild Steel SS400 JIS G3101 Dengan Metode Elektroplating Ni-Cr

Mild steel is steel with a concentration of carbon element below 0.3%. In its use as an oil storage tank material on fuel transport trucks, there is a problem, namely its resistance to corrosion in fuel. Sulfur compounds in fuel have a role in the formation of corrosion. Currently, the Ni-Cr electroplating coating method is very widely used as an effort to control the corrosion rate of carbon steel. The use of Ni-Cr as an anode is relied upon as a substance resistant to corrosion. Therefore, the purpose of this study was to identify how layer thickness affects corrosion levels in SS400 mild steel based on current variations and duration of the electroplating process. In this study using mild steel SS400 JIS G3101 with electroplating method (electroplating) varying the electric current 1A, 2A and 3A, as well as electroplating time of 10 minutes, 20 minutes and 30 minutes. The test parameters of the electroplating results are the actual layer thickness test, theoretical thickness test and corrosion rate test. Data processing was analyzed using two-way variance analysis. The thickness of the layer increases with increasing electric current and the length of time of Ni-Cr electroplating. The highest thickness value of 102.34 μm using a digital microscope while for theoretical testing of 98.33 μm, both were obtained at a current variation of 3A and an electroplating time of 30 minutes. The trend of corrosion rate value will decrease with the increase in electric current and the length of electroplating time with the lowest value of 0.003359 mmpy at a variation of electric current 3A and electroplating time of 30 minutes. For optimal values with the lowest corrosion rate on mild steel SS400 JIS G3101 as an oil storage tank material on fuel transport trucks, it is obtained by using a current of 3A and an electroplating time of 30 minutes Ni-Cr.

The impact of corrosion due to salinity levels in the eastern zone of krueng aceh on the service life of steel frame building structural elements

Abstract The use of profile steel as the main element in construction has gained significant popularity due to its mechanical strength and ease of workability. Corrosion is a problem that occurs within steel as a result of the chemical interaction between the steel and its surrounding environment. The purpose of this research is to assess the impact of corrosion rate on the service life of steel frame structures in the East Zone of Krueng Aceh based on varying levels of salinity. This study employs direct observation and an experimental method that carry out testing on-site for 30 days on test objects/items. The test specimens consist of steel plates measuring 50mm x 25mm x 5mm with BJ45 quality, which were cut and buried in soil excavated to a depth of approximately 1 to 2 meters for one month while submerged. Subsequently, calculations were made using the Weight Loss Method to obtain the corrosion rate value.The results obtained in Zone II, which has the highest salinity level of 6788 ppm, yielded a corrosion rate value of 0.145 mm/year. In this study, the structural element under consideration is the column. Remaining service life analysis is based on the reduction in the cross-sectional area of the column profile after corrosion, thus assessing the decrease in its strength while referring back to the requirements outlined in SNI 1729:2020. The remaining service life of the steel frame structure in Zone II after corrosion is 21 years. For the test specimens placed in Zone IV, which has the lowest salinity level of 941 ppm.

Prediction of external corrosion rate for buried oil and gas pipelines: A novel deep learning method with DNN and attention mechanism

Buried pipelines is easily subjected to external corrosion affected by complex underground environment, such as soil resistivity, pH, dissolved ion concentration, water content and coatings condition. Therefore, external corrosion rate prediction is essential to ensure pipelines intrinsic safety. Generally numerous researches focused on mathematical models and degradation analysis are limited to considering comprehensive corrosion factors. In this work, a novel proposed deep learning method involves a deep neural network (DNN) and attention mechanism which has good robust generalization ability. DNN was used to predict external corrosion rate of buried pipelines with extracting corrosion characteristics data, and attention mechanism is carried on weighting operations of corrosion factors furtherly. The results show that main controlling factors are pipeline age and soil bulk density, sulfate ion concentration and redox potential have less effect by analyzing external corrosion factors dataset, and data reduction and standardization of DNN-attention mechanism model are carried out. The external corrosion rate value predicted by the DNN-attention mechanism model is the closest prediction with the real truth, which the evaluation index root mean square error (RMSE) is 0.0064, and prediction accuracy is 91.91 % compared with convolutional neural network (CNN), CNN-residual, DNN. It proves that it is reasonable to predict pipeline external corrosion rate using DNN-attention mechanism based on publicly pipeline corrosion dataset.

Failure assessment of corroded offshore pipelines using code-based approaches and a combination of numerical analysis and artificial neural network

The main purpose of the present paper is to investigate the failure pressure and the remaining life of the corroded offshore pipelines utilizing code-based methods such as ASME B31G, modified ASME B31G, DNV RP-F101 and FFS Level-1. Besides, the results of these approaches are compared with the responses of Finite Element Method (FEM) using Artificial Neural Network (ANN) model. To this purpose, the probability distribution of the corrosion defect length and depth as well as the corrosion rate values are obtained from an In-Line Inspection (ILI) survey of an offshore pipeline project in the Persian Gulf. In addition, a 3D verified numerical model of a corroded pipeline is constructed to conduct the numerical analyses. Using the numerical analysis data, a Multi-Layer Perceptron (MLP) model is created to estimate the failure pressure of the pipeline with arbitrary defect dimensions. Moreover, the remaining life of the corroded pipeline is quantified in order to prevent the catastrophic consequences of the pipeline failure. The results show that the MLP model is capable of estimating the failure pressure of the corroded offshore pipeline with quite acceptable accuracy compared with the mentioned code-based methods. Furthermore, the calculated failure pressure of the corroded pipeline can be sorted in ascending order as: (1) FFS-Level 1 (2) ASME modified B31G (3 & 4) ASME B31G & DNV RP-F101 (5) FEM + MLP. In fact, the failure pressure and the remaining life calculated by DNV RP-F101 are closer to the FEM + MLP results for the defects with small and medium dimensions. Diversely, the DNV RP-F101 method underestimates the failure pressure of the corroded pipeline when the defect dimensions become larger.

A comparative analysis of corrosion assessment techniques for steel in reinforced concrete exposed to brine water environments

Abstract Corrosion assessment of steel-reinforced concrete specimens submerged in synthetic brine water with various chloride concentrations for 1–16 weeks was performed. Mass loss measurements combined with electrochemical techniques – half-cell potential, linear polarization (LP), and electrochemical impedance spectroscopy (EIS) – were employed. The results obtained from all corrosion assessments – on-site testing (half-cell potential measurements), laboratory scale (LP and EIS measurements), and destructive testing (mass loss or immersion measurements) – exhibited remarkable consistency, complementarity, and mutual supportiveness. Corrosion rate (CR) values from mass loss were close to those obtained from LP and EIS. The corrosion resistance decreased with increasing chloride concentration and immersion time, as indicated by the highest CR, Ca2+, and Fe2+ concentrations, and the lowest half-cell potential and polarization resistance. X-ray photoelectron spectroscopy investigation on the corroded steel surface revealed Fe(III) oxides and hydroxides and Fe(III) (FeCl3), corresponding to the reduction in polarization resistance in the LP and EIS results.

The electrochemical corrosion behavior of Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy with different initial microstructures

The corrosion behavior of Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy with different initial microstructures was investigated by conducting a series of electrochemical tests. Based on the experimental data, the effects of NaCl solution concentration and corrosion time on the electrochemical polarization curves, corrosion rates, electrochemical impedance spectroscopy (EIS), and impedance of the alloy with two initial microstructures were analyzed. The assessment of the corrosion current density (Icorr) and corrosion rate (CR) for the alloy under different corrosion conditions reveals a general pattern of initial decrease followed by increase in their values with extended corrosion time and elevated solution concentration, whereas the capacitive reactance arc exhibits an opposite trend. For alloys with initial equiaxed microstructures, the Icorr value is 0.1892 μA/cm2, and the CR value is 0.000413 mm/year; these values are lower than those of 1.298 μA/cm2 and 0.002842 mm/year for alloys with initial lamellar microstructures. Whereas the capacitive reactance arc and the impedance value are greater for the titanium alloy with initial equiaxed microstructure. Based on the adsorption kinetics principles, the effects of temperature on corrosion rate of alloys with different initial microstructures at a consistent concentration were analyzed. Compared to the alloy with initial lamellar microstructure of 3054 kJ/mol, the alloy with initial equiaxed microstructure had an activation energy of 4155 kJ/mol. As the temperature rises, the rate of corrosion tends to increase. The results suggested that the alloy with initial equiaxed microstructure presented the superior corrosion resistance than the alloy with the initial lamellar microstructure. Additionally, the corrosion morphologies after polarization of the alloy were characterized. And the results show that the surfaces of titanium alloys with initial lamellar microstructure display a comparatively greater incidence of pitting corrosion upon assessment of the corrosion morphology.

Corrosion Behaviour of Stainless Steel 316L in Chloride Environment After Dry Machining by Face Milling at Various Spindle Speed

This study attempts to investigate the impact of spindle speed on the corrosion characteristics of 316L stainless steel during the face milling process in dry condition. The machining parameters, such as spindle speed, have an impact on the surface properties of the material after the processes. It is essential to devote significant attention that these parameters can still affect the surface condition of 316L stainless steel, which may then affect its corrosion properties. This research aimed to examine the corrosion characteristics of 316L stainless steel subsequent to the face milling process using the potentiodynamic polarization technique in a chloride-containing environment. The face milling technique use a 6 mm carbide cutter tool, with spindle speed variations of 1800 rpm, 1600 rpm, and 1400 rpm. The feed rate is maintained in constant rate, which is 0.002 mm/rev. The findings of the corrosion rate test indicate that variations in spindle speed lead to fluctuations in the corrosion rate value. There finding shows an inverse relationship between the value of spindle speed and the corrosion rate, wherein an increase in spindle speed corresponds to a decrease in the corrosion rate.

Efektivitas Hasil Pengelasan SMAW pada Baja ST 37 Dengan Variasi Jenis Elektroda dan Kuat Arus Terhadap Pengujian Tarik dan Korosi Bermedia Larutan H2 S0_4

To support the rapid development of industry at this time, especially in the machinery industry, it has also spurred the development of technology for making basic materials such as steel. ST 37 steel is steel produced for making various machinery components. To improve the mechanical properties of ST 37 steel, a heat treatment process is applied. To see the service life of steel, it is also necessary to pay attention to the rate of corrosion that will occur in the steel that will be used in machine components. The aim of this research is to determine the use of the right type of electrode and current strength to achieve its effective use, with the criteria that the steel has tensile strength when a tensile reaction occurs in the steel and the steel has good corrosion resistance. In this study, the electrode variations used were AWS E6010, E6013, and E7016 electrodes, with variations in current strength of 70 A, 85 A, and 110 A. The highest tensile strength values ​​during the drawing process occurred in specimens with strong AWS E7016 electrode variations. The current was 110 A. Meanwhile, the lowest tensile strength occurred in the specimen with the AWS E6013 electrode variation with a current strength of 70 A. The highest corrosion rate value occurred in the AWS E6010 electrode variation specimen with a current strength of 70 A, while the lowest corrosion rate occurred in the specimen. with AWS E7016 electrode variations with a current strength of 110 A.

Corrosion behavior of high- and low-chromium steel grinding balls in chloride solution

The corrosion behaviour of three types of alloys (two low-alloy carbon steel and one stainless iron with ~15 wt.% Cr), in a solution which simulates seawater (3% NaCl solution, pH 8.1) was tested. Tested samples are used to make steel (iron) balls applied in mils for grinding copper and other ore. The corrosion tests were performed using three electrochemical methods, at room temperature in the presence of atmospheric oxygen. The linear polarization resistance (LPR) method, electrochemical impedance spectroscopy (EIS) method, and linear sweep voltammetry (LSV) method were applied. Based on measurements by LPR and EIS methods (as non-destructive methods), the value of polarization resistance (Rp) was determined and the general corrosion rate (vcorr) of the examined samples was calculated. The obtained values of the general corrosion rate can be used to calculate the service life of steel (iron) balls under exploitation conditions (seawater). The appearance of the surface after linear sweep voltammetry (LSV) measurement showed the presence of localized corrosion (pits were formed) of the tested samples, especially stainless iron, and the LSV method is not suitable for the determination of the general corrosion rate of tested samples in seawater. This form of corrosion occurs at high anodic polarizations, during performing LSV measurements.

Methods for evaluation of corrosion rate on magnesium alloys: a review

The major drawback of some magnesium alloys is their low corrosion resistance. Therefore, the evaluation of corrosion resistance is a critical factor in developing new alloys and surface treatments. The techniques employed for the determination of corrosion rate include mass loss assessment, hydrogen evolution, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). However, there are still difficulties in precisely estimating this parameter in Mg alloys. In this review, the reported applications, advantages, and disadvantages of the techniques mentioned above were analyzed. On the other hand, a large number of corrosion rate values reported for various Mg alloys in 3 different media (NaCl, Hanks´ solution and SBF), using mass loss, hydrogen evolution, and PP, were compared and analyzed. Generally, corrosion rates obtained from mass loss are higher than those obtained from hydrogen evolution. On the other hand, it is not possible to obtain correlations between corrosion rates obtained from PP and those obtained from mass loss and hydrogen evolution. Even more, dissimilar corrosion rate values are reported for the same alloy, implying that the measuring procedures are not well standardized.

Działanie antykorozyjne wybranych odczynników na korozję stali węglowej w wodzie złożowej zawierającej siarkowodór

For the first time, the impact of the composition of gossypol resin and IB-1 reagent, prepared in a 3:1 ratio and conventionally named HS-1, on the corrosion rate in hydrogen sulfide formation water has been investigated under laboratory conditions. Concentrations of 20, 40, 60, 80 mg/l of the new composition were used. During the experiments, a formation water sample taken from well No. 1082 of “Bibiheybatneft” OGPD, SOCAR, served as the electrochemical corrosion medium for the study. To conduct a comparative analysis, gossypol resin, IB-1 inhibitor, and HS-1 composition were used. Concentrations of 50, 100, 150, 200 mg/l of gossypol resin and 10, 15, 20, and 25 mg/l of IB-1 inhibitor were employed in the experiments. Numerous laboratory experiments revealed that the optimal consumption rate for the HS-1 inhibitor is 100 mg/l, for gossypol resin it is 200 mg/l, and for the IB-1 inhibitor it is 25 mg/l. These experiments were conducted under dynamic conditions over six hours. It was determined that the newly developed HS-1 composition offers superior protection in an aggressive medium containing hydrogen sulfide compared to its constituent components, gossypol resin, and IB-1 inhibitor. Specifically, as the concentration of gossypol resin in formation water increases from 50 to 200 mg/l, the corrosion protection effect ranges from 60–82%. When the concentration of IB-1 inhibitor varies between 10–25 mg/l in a hydrogen sulfide medium, the protection effect lies between 65-90%. In the aggressive medium of hydrogen sulfide formation water, increasing the concentration of the new HS-1 composition from 30–80 mg/l results in an enhancement of its electrochemical corrosion protection effect, ranging from 74–98%. Upon analyzing the results of numerous laboratory experiments, it was found that the optimal consumption rate of gossypol resin for corrosion protection in an aggressive medium with hydrogen sulfide is 200 mg/l, the consumption rate of IB-1 inhibitor is 25 mg/l, and for the HS-1 composition is 80 mg/l. The corrosion rates for gossypol resin in the concentrations of 50, 100, 150, 200 mg/l is 1.72, 1.38, 1.12, 0.78 g/m2 · h and retardation coefficient is 2.50, 3.10, 3.84, 5.51, respectively. Corrosion rate of IB-1 inhibitor concentration in the amount of 10, 15, 20, and 25 mg/l is 1.5, 1.12, 0.78, 0.43, and retardation coefficient is 2.86, 3.84, 5.51, 10.0, respectively. The corrosion rates for the new HS-1 composition at concentrations of 20, 40, 60, 80 mg/l is 1.12, 0.73, 0.34, 0.08, and the retardation coefficient is 3.84, 5.89, 12.64, 53.75, respectively. Comparing the corrosion rate values obtained for all three reagents with the corrosion rate for hydrogen sulphide formation water shows that new HS-1 composition has a higher effectiveness compared to its constituent components.