Polarization Resistance Method Research Articles

Empirical Study of the Effect of Nanocoolant Particles on Corrosion Rate of 316 Stainless Steel

The advancement of nanotechnology has had an impact on the use of heat exchangers. Nanocoolants, which offer higher thermal efficiency than traditional coolants, have paid significant attention. These innovative fluids, which contain nanomaterials, not only have better heat efficiency but also improve energy efficiency compared to regular coolants. However, the presence of solid nanoparticles in the coolant may cause corrosion and erosion of tubes, leading to massive degradation of those parts. To evaluate the effectiveness of nanocoolant particles, this research was conducted by studying the impact of using nanocoolant on erosion-corrosion occurring on metal surfaces. The study focused on the erosion-corrosion of stainless steel (AISI 316) in coolant solutions containing nanoparticles. The experiments utilized a rotating cylinder electrode (RCE) with rotational speeds ranging from 0 to 1800 rpm and a temperature range of 30°C-70°C. The corrosion rate was determined using the linear polarization resistance (LPR) method, while the erosion was measured by calculating the average surface roughness of the samples. The design of the experiment (DOE) was utilized to find the mathematical expressions of the effects of the nanocoolant on erosion and corrosion. The findings revealed that the corrosion rate and surface roughness of the samples increased with an increase in temperature and rotation speed. Furthermore, the erosion-corrosion effects of the nanocoolant were less significant in stagnant conditions than in flow conditions, and significant differences were observed when compared with conventional coolant. Additionally, synergistic erosion and corrosion processes were detected at higher temperatures and higher rotation speeds for both types of coolants.

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.

Mechanism of inhibitory action of fruit cake extracts as a new environmentally inhibitors of carbon steel corrosion

In this study the firstly study reported on the use of plum, cherry, nectarine and apple pomace extract as corrosion inhibitors of steel in water solution. Potentiodynamic polarization study showed that extracts act as a mixed type inhibitors with dominant cathodic effect. Linear polarization resistance method (LRP) assesses the time-related effect of inhibitors during open circuit potential corrosion. The results show that the inhibitory efficiency of our extract increases with increasing time formation protective film to reach 99 % in a concentration of 500 ppm. LC - MS and FTIR spectroscopy techniques can be concluded that several water-soluble interaction products of chemical reaction in NaCl are identified namely flavanol–anthocyanin and flavanol-aldehyde adducts. Subsequently, the iron-mediated complexation and oxidation of the extract components (flvonoids) in the aqueous solution were explored using UV-spectrophotometric and HPLC methods. With the passage of time, iron-mediated oxidative degradation and coupling reactions occurred, resulting in the production of hydroxybenzoic acid derivatives. Consequently, the inhibition decreased after 24 h. The chemisorption type of interaction of the product formed in the inhibited solution forming the adsorption-polymerization layer with the steel surface is established. Based on the quantum-chemically calculated parameters of the electronic structure of flavanol–anthocyanin and flavanol-aldehyde adducts, it was established for the first time that the combination of reactive fragments in them, which are spatially located in different planes with a higher quantity of hydroxyl groups, increases their adsorption activity and, as a result, their inhibitory capacity.

Исследование стойкости лекарственного покрытия на медицинских стентах

One of the effective methods of treatment of cardiovascular diseases is a minimally invasive method of surgical intervention called stenting. The structure of the stent in the form of a cylindrical metal mesh makes it possible to deliver the implant to the place of installation in a compressed state and, on site, to expand it to the size required by the vessel. To reduce the risk of restenosis, drug-coated stents are used in drug therapy. Despite this, to date, it has not been possible to completely prevent the development of restenosis. In this regard, the works on the development of drug coating composition and methods of their application on the metal surfaces of the medical stent are relevant. Studies on the development of a drug coating based on polyvinylpyrrolidone with the addition of acetylsalicylic acid have been carried out. This coating was applied to the surface of the medical stent analog by electrochemical deposition. The obtained drug coating was evaluated. Corrosion tests of the investigated samples with the applied coating were carried out by polarization resistance method. The dependence of corrosion resistance of the material on the concentration of acetylsalicylic acid in the composition of the drug coating was revealed.

Fabrication and evaluation of silver-doped magnesium oxide nanocomposite coatings for orthopaedics applications

Stainless steel 316L (SS 316L) is primarily used as implant material in orthopaedic applications for the treatment of bone fractures and joint replacement surgeries due to its excellent mechanical strength and cost-effectiveness. However, its long-term implication, susceptibility to infection and subsequent lack of integration with surrounding tissues remain significant challenges resulting in implant failure. To address these issues, the development of advanced coatings with improved antibacterial properties, biocompatibility, wear and corrosion resistance is of paramount importance. In this study, the potential of an Ag doped MgO nanocomposite coating on stainless steel 316L substrates has been explored for orthopaedic applications. The Ag-MgO nanocomposite was synthesised using the hydrothermal method. The composition, crystallinity, and morphology of the synthesised nanocomposite was investigated using different techniques such as X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) attachment. SEM and XRD results confirmed, that the synthesised nanocomposite had a platelet shape with a cubical crystal lattice network and an average size of about 10nm. The spin coating technique was employed to produce an Ag-MgO nanocomposite coating onto the SS 316L substrate. The bactericidal efficiency of Ag-MgO nanocomposite-coated SS 316L substrates was examined against Staphylococcus aureus and Escherichia coli bacteria using well diffusion method, while an MTT assay was performed to determine the cytotoxicity of the uncoated and coated SS 316L substrate against mouse embryonic fibroblast cell line (NIH-3T3). The effectiveness of wear and friction resistance of Ag-MgO nanocomposite-coated substrate was also evaluated via a ball-on-disc tribometer. Furthermore, corrosion behaviour evaluation using a linear polarisation resistance method confirms the significant improvement in corrosion resistance of coated substrate than the uncoated substrate. Overall, the results demonstrated that the Ag-MgO nanocomposite coating on SS 316L substrates improves its performance for orthopaedic applications.

Effect of Imperial Smelting Process Slag Addition in Self Compacting Concrete Concrete on the Efficiency of Electrochemical Chloride Extraction.

This paper presents the analysis of how ISP slag addition affects the effectiveness of chloride extraction from self-compacting concrete. Corrosion processes were initiated by chloride ions added to concrete by the method accelerated with an electric field. Corrosion of reinforcement was monitored using the method of linear polarization resistance (LPR). Polarization measurements of steel reinforcement and chloride profiles were analysed to evaluate the effectiveness of electrochemical extraction. Microstructural analysis was conducted on a specimen of concrete after migration and extraction of chlorides. The presence of chloride ions and the application of an electric field during migration were tested with respect to the changed microstructure of concrete evaluated on the basis of image analysis using a scanning electron microscope (SEM). The research contributes to a better understanding of the corrosion processes caused by the presence of chloride ions in concretes in which ISP slag was used as a substitute for sand in various amounts. Thanks to the treatments of concrete with already corroding reinforcement bars, it can be concluded that the moderate replacement of sand with ISP slag limited to 25% allows for the effective inhibition of corrosion processes taking place in these concretes. However, it is not possible to completely withdraw already started corrosion processes in steel. The observations of the microstructure of concrete in which sand was completely replaced with ISP slag indicate that after prolonged use of the chloride extraction process, we can expect a change in the microstructure and the formation of ettringite, which may cause the concrete structure to burst. The obtained information will contribute to the development of modelling methods for chloride ion extraction from a wide range of currently used concretes.

Residual mechanical performance and rust characterization of self-prestressing UHPM subjected to chloride-induced corrosion

Chloride-induced corrosion poses extreme vulnerabilities to the strength degradation and delamination of reinforced concrete structures in the oceanic environment. For this reason, the self-prestressing effect produced from the synergy of the combined addition of expansive agent (EA) and steel fibre (SF) into the concrete is suggested to enhance the corrosion performance (cracking and degradation) of concrete-steel tubular columns (CSTCs). Four mortar mixtures were prepared with the no EA and SF, individual use of EA or SF and combined use. The corrosion rate was measured by the linear polarization resistance (LPR) method, while crack-width and pit-depth were measured with scanning electron microscopy (SEM). Test results revealed that the self-prestressing ultra-high-performance mortar (UHPM) prepared by the combined use of EA and SF reduced the corrosion rate, pit depth, and crack width up to 87.3%, 55.8%, and 68.3%, respectively. Furthermore, it also results in the highest residual compressive strength. The corrosion products characterized by using an energy-dispersive x-ray detector (EDX) and x-ray diffractometry (XRD) for self-prestressing UHPM were oxides with a volume ratio to parent iron of approximately 2, which is the lowest amongst all and justifies its superior performance.

On-line monitoring the corrosion rate of reinforcing steel in concrete under natural conditions using bimetallic batch sensors along the coast of Khanh Hoa (Vietnam)

A bimetallic batch sensor was proposed to assess the corrosion rate of steel reinforcement in concrete in the presence of chlorides under laboratory and marine conditions. The prepared sensor could generate an electric current independently, indicating the corrosion process's intensity. Moreover, this sensor did not require any external polarization, resulting in reducing the device's cost and power consumption. These advantages are very important when using sensors for autonomous monitoring systems away from energy sources. Laboratory tests in an aqueous extract of concrete have shown the possibility of a sensor to detect the transition from a passive state to corrosion with an increase in the concentration of chlorides. Activation was received when 0.010 < CCl ≤ 0.10 mol·dm−3. The boundary between the passive state and corrosion was obtained at a current density of 8.6 ± 0.5 μA·cm−2. The measurement results on the sensor coincided with the data of the anode polarization curves and the polarization resistance method. In addition, the monitoring system based on sensors was tested in the field conditions of Khanh Hoa (Vietnam) for four exposure conditions for nine months. The correspondence of the measured current for sensors with standard monitoring methods was obtained: the half-cell potential and the electrical resistivity. The most intense corrosion occurred for the samples placed in the splash zone or immersed to a depth of 1 m. The coefficient of conversion of the current on the sensor and the corrosion rate by the polarization resistance method for concrete samples was set to 69.9. Therefore, it is possible to use the current value on the sensor to predict the time to structural failure using well-known models based on data on the corrosion rate of reinforcement. The sensors could retain their functionality and integrity after 9 months of field tests. The current findings suggest a continuous monitoring system of the corrosion rate of steel reinforcement in marine conditions for practical applications.

Corrosion of metal parts in the power plant

AbstractThe AISI 304 (X5CrNi19‐10) stainless steel is widely used for the production of various metal parts in power plants. A procedure for testing the influence of the dust from a power plant on resistance to general and pitting corrosion of the AISI 304 stainless steel is developed and performed. The quantitative (XRD method) and qualitative (Fourier–transform infrared spectroscopy [FTIR] method) composition of the dust present in the power plant is determined. Applying the Mott–Schottky method, the properties of the passive layer are analyzed, while a degree of chromium depletion of the grain boundary is determined by the electrochemical potentiokinetic reactivation method with double loop method. Values of polarization resistance (linear polarization resistance and electrochemical impedance spectroscopy methods) and the corrosion current density (polarization measurements) indicate that the stainless steel has a higher resistance to general corrosion in the dust solutions than in the etalon solution. Also, based on the measured value of the pitting potential (Epit) and the difference between the values of the pitting potential and the corrosion potential (Epit – Ecorr), it can be seen that stainless steel has a higher resistance to localized types of corrosion, such as pitting corrosion, in dust solutions than in the etalon solution.

Effect of different types of calcined crude kaolins and high purity metakaolin on corrosion resistance of reinforcement in concretes: Experimental evaluation and analytical modeling

In this experimental study, the corrosion characteristics of steel reinforcement bars embedded in concretes, which were produced by incorporation of metakaolin obtained from high purity metakaolin or calcined raw kaolins, were investigated. The linear polarization resistance (LPR) method was benefited as the corrosion monitoring method. In concrete production, 0.40 water/binder ratio, 350 kg/m3 total binder amount, two different mineral admixture replacement levels of 5% and 15% were used. In addition, control samples were produced to evaluate the effectiveness of mineral additives. Reinforced concrete samples manufactured for accelerated corrosion monitoring were submerged into NaCl solutions of two different concentrations (2% and 5% solutions) to provide rapid anodic reactions in corrosion process. Additionally, the electrical resistance values of the concretes were tested to assess the corrosion behavior. After the experimental results were achieved, the obtained data were evaluated statistically and a new mathematical estimation model was developed using the gene-expression programming (GEP) method taking into account the effective parameters. This model was also compared with the results of the multiple linear regression, which is a statistical method. The analysis of the results based on LPR technique showed that the modified samples yielded higher corrosion resistance than the plain samples in both solution exposure conditions. Among the mineral additives used, it was observed that those with metakaolin addition had the highest resistance. While the coefficient of determination (R2) of the testing set produced for the GEP prediction model was around 0.9, the value obtained by multiple linear regression was found to be 0.433.

Comparison of the Mechanical Properties and Corrosion Resistance of the Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN Coatings

In this work, the mechanical properties and corrosion resistance of Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings deposited by the physical vapor deposition (PVD) method on Ti-6Al-4V alloy were compared. The phase composition of the coatings, their hardness and fracture resistance in scratch tests were determined, and their structural characteristics were also studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The diffraction spectra were made using an automatic X-ray diffractometer. The value of the adhesive component of the friction coefficient fadh of the pair “coated and uncoated Ti-6Al-4V alloy” was investigated in the temperature range of 20–900 °C. The lowest value of fadh was detected for the Zr-ZrN coating at temperatures below 400 °C, while for the Mo-MoN coating it was observed at temperatures above 700 °C. The polarization curves of the coated and uncoated samples were performed in a 3% aqueous NaCl solution. The level of corrosion of the Ti-6Al-4V alloy samples with Cr-CrN, Ti-TiN, Zr-ZrN, and Mo-MoN coatings was evaluated using the Tafel extrapolation method, the iteration method, and the polarization resistance method. The results obtained with these methods indicate that the Zr-ZrN coated sample has the best corrosion resistance in the 3 wt.% NaCl solution, with a corrosion current density of 0.123 μA/cm2.

К ОЦЕНКЕ ИНГИБИТОРНОЙ ЗАЩИТЫ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ И ОБОРУДОВАНИЯ

Possible criteria for the effectiveness of inhibitor protection of agricultural machinery and equipment: integral and differential; quantitative, semi-quantitative, qualitative; a generalized quantitative assessment based on the weightiness of each type of destruction; mass, deep, volumetric; technical and economic; environmental and toxicological, etc. were considered. It was noted that each of the criteria taken separately is not always unambiguous in specific conditions, which can lead to a subjective assessment of the appropriateness of using certain corrosion inhibitors (CI). Electrochemical methods for assessing the effectiveness of inhibitor protection are highlighted as promising, which is associated with the desire of researchers to reduce the time of corrosion testing. As an example, a study of the metal-protective coating-electrolyte system by the method of polarization resistance with an assessment of the contribution of each component is considered. Compositions based on trans-former TKp, industrial I-20A, motor M10G2k, fresh and used (MMO), and combined IR CortecVpCI-368 and Cortec VpCI-369 were studied. Coatings on steel were preliminarily formed during the day. Comparison of the results on the protective effectiveness of compositions in I-20A with those also obtained by the method of polarization curves and gravimetric methods in a 0.5 M NaCl solution and in a thermal moisture chamber G-4 showed qualitatively similar results, which indicates the reliability of the results obtained by the method of polarization resistance. The maximum protective efficiency is observed for compositions based on MMO with an IC concentration of 3 -10 wt. % in MMO.

The Influence of Different Type Materials of Grit Blasting on the Corrosion Resistance of S235JR Carbon Steel

The aim of this paper is to evaluate the corrosion rate expressed in material loss per unit of time and the surface properties of carbon steel type S235JR blasted with different types of materials (quartz, alumina, and red garnet with a particle size between 60 and 80 mesh (0.25–0.60 mm)). The estimation of corrosion rate was determined by electrochemical methods, such as open circuit potential (OCP), polarization resistance (Rp), corrosion rate (Vcorr), and gravimetric method by immersing the samples in 3.5% NaCl solution for a period of 336 h. All surfaces were characterized before and after corrosion tests using ex-situ characterizations, such as optical microscopy and roughness analysis. The results indicate that S235JR non-sandblasted exhibited higher polarization resistance, the lowest corrosion rate, and the lowest roughness values. While for the S235JR sandblasted groups, reduced corrosion resistance and increasing roughness values were noted. From the sandblasted groups, the lowest corrosion resistance and the highest value of roughness are attributed to the S235JR surface sandblasted with quartz. The S235JR surface sandblasted with quartz shows a decrease in corrosion resistance approximately two times lower than the non-sandblasted surface and an increasing of roughness approximately six times greater than the non-sandblasted surface.

Steel corrosion rates in concrete in contact to sea water

There are few data on corrosion rates of reinforcements in real marine conditions. In present work corrosion rates at long term are presented in the case of small specimens and large reinforced concrete blocks in direct contact to natural sea water. The small specimens had embedded bars at different cover depths and the tests lasted from 10 to 23 years and the corrosion rates have been measured periodically by using the polarization resistance method. The large blocks have been semi-buried around 25 years in the tidal area of a beach in the South of Spain. Their corrosion rates have been measured only four times and the curiosity is that the bars are not corroding in spite of the high contamination at the 3 cm cover depth after so long exposure. Finally, is presented the statistical distribution of corrosion rates found in other structures also in marine environment.

Methods for determining the rate of corrosion with the application of a corrosion inhibitor produced on the basis of secondary raw materials

This article describes the synthesis technology of a new corrosion inhibitor based on formalin, thiosemicarbazide, and orthophosphoric acid, as well as the method of determining the corrosion rate of the synthesized corrosion inhibitor by polarization resistance and gravimetric method. The effectiveness of the synthesized corrosion inhibitor against corrosion caused by the acid in the mixture of gases from mines in gas treatment plants has been reflected in the results of research and testing. Also, the effectiveness of the corrosion inhibitor and the braking coefficient were determined.

An Experimental Evaluation of The Three Types of Corrosion, Passivation, Pitting, and Uniform Corrosion, by Electrodeposited Chromium-Nano Diamond Composite Coating on Porous Materials

Incorporation of nano scale particles in coatings of metals are known as nano composite coatings are a new form of materials with enhanced hardness, wear, and corrosion resistances. In this study, pre-alloy metal powder metallurgy specimens were subjected to electrolytic coating of pure chromium and Cr-ND (Chromium-nano diamond). The influences of the co-deposited ND particles on passivation, pitting and uniform corrosion behavior of the chromium coatings were experimentally inspected and compared with pure chromium coating and non-coated specimens. The corrosion behaviors of the samples were analyzed by Polarization Resistance, Cyclic Voltammetry and Electrochemical Impedance Spectroscopy measurement methods under 3.5 %wt. NaCl solution. Furthermore, characterization tests were carried out using an optical microscope, SEM (Scanning Electron Microscope), EDS (Energy Dispersive X-Ray Spectroscopy), XRD (X-Ray Diffraction) and AFM (Atomic Force Microscope). According to the obtained results, it was observed that as compared to pure chromium coatings and non-coated specimens, a convincing improvement in the corrosion behavior of the Cr-ND coatings was obtained because of the incorporation of the ND particles in the chromium matrix.

Non-destructive monitoring of incipient corrosion in reinforced concrete with top-bar defect using a combination of electrochemical and ultrasonic techniques

Top-bar defect in reinforced concrete (RC) leads to the formation of interfacial voids underneath the reinforcements at an elevation of 300 mm or more. Rebars with top-bar defects show earlier corrosion initiation, faster corrosion rate and a different pattern of corrosion, compared to those without. This paper proposes combined electrochemical and ultrasonic methods for monitoring incipient corrosion in RC. An RC wall structure is cast vertically aiming to create top-bar defect. The specimens were subjected to accelerated chloride-induced corrosion. Simultaneously, they have been monitored with half-cell potential method (HCP), linear polarisation resistance method (LPR), ultrasonic guided waves (GW) and ultrasonic imaging (UI). The pros and cons of the four techniques are determined and discussed. The results are correlated and calibrated with the state of corrosion. Key milestones of the corrosion mechanism such as corrosion initiation and crack initiation can be successfully identified and the progression of bar deterioration, steel-concrete interfacial debonding and cracking propagation have been traced.

The equivalent quantization method of corrosion damage of reinforcement cage for concrete beam and its durability in island and reef environment

• The equivalent quantization method of corrosion damage of concrete beam was proposed and verified. • Effects of four factors with twelve levels on durability of concrete beam were studied. • Three types of self-produced protective materials were tested. • The relation between the linear polarization resistance and electrochemical impedance spectroscopy methods was established. The electrochemical measurement technique was used to conduct a non-destructive test the corrosion degree of reinforcement cage for concrete beam in tidal environment of island and reef region in real-time. Apart from this, the corrosion resistance of concrete beam with different concrete strength grades, steel bar, darex and migrating corrosion inhibitors, including three types of self-produced protective materials, was studied. Furthermore, based on electrochemical parameters, the relation of electrochemical measurement techniques was established. The results showed that the proposed equivalent quantization method of corrosion damage could be available for the reinforcement cage in concrete beam. In addition, the durability of concrete beam in tidal environment of island and reef region can be effectively improved by improving the concrete strength grade and the corrosion resistance of steel bar and using darex and migrating corrosion inhibitors. The polarization resistance obtained by the linear polarization resistance method and charge transfer resistance obtained by the electrochemical impedance spectroscopy method were linear. This study provides a key technology for actual reinforcement corrosion in concrete structure and some protective measures.

On the corrosion rate measurement of reinforcing steel in chloride induced macrocell corrosion

This study investigates the corrosion rate measurement of reinforcing steel under chloride-induced macrocell corrosion in reinforced concrete (RC). The corrosion rates of RC columns with different cover thicknesses and chloride concentrations were evaluated using different techniques and cathode over anode ratios. The applicability of the Stern-Geary equation on the macrocell corrosion of RC was studied. The results show that the corrosion rate of highly corroding steel can be underestimated by an order of magnitude by the linear polarisation resistance method due to a failure to compensate for diffusion resistance. The effect of macrocell corrosion on the measurement of polarisation resistance is moderate with a relative error less than 2. The galvanostatic polarisation technique can eliminate the influence of diffusion resistance and therefore reliably measure polarisation resistance. A B value of 52 mV is recommended under macrocell corrosion.

Effect of cation type on corrosion of steel treated by DNA corrosion inhibitor in simulated concrete pore solution

The purpose of this study is to evaluate the influence of cation types on the rust resistance performance of new nucleic acid corrosion inhibitors in simulated concrete pore solution. Four common chlorinated ice salts (sodium chloride (NaCl), potassium choride (KCl), calcium chloride (CaCl2) and magnesium chloride (MgCl2)) were selected to study the corrosion behaviour of chloride ions by linear polarisation resistance method, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results show that the cationic type will affect the thickness of the passivated film on the steel surface and the compactness of the passivated film formed by iron oxide and nucleic acid rust inhibitor. The type of cations affects the critical chloride concentration of nucleic acid inhibitor, following Na+ ≈ K+ &gt; Ca2+ &gt; Mg2+.