Tafel Extrapolation Method Research Articles

OPTIMIZATION OF EROSION–CORROSION BEHAVIOR OF NICHROME COATED 2205 DUPLEX STAINLESS STEEL USING GREY RELATIONAL ANALYSIS

Erosion–corrosion is a common mechanism in the degradation of systems in the mining, chemical, and petrochemical industries. Surface modification can help to reduce the detrimental effects of erosion–corrosion. This study uses the plasma spray process for coating nichrome on duplex stainless steel (DSS2205) to improve the surface characteristics. Erosion tests were performed to analyze the effect of parameters such as impact velocity (150, 175 and 200[Formula: see text]m/s), impact angle (30∘, 60∘and 90∘), and erodent particle discharge rate (2.5, 3.75 and 5[Formula: see text]g/min). According to the findings, the maximum erosion rate ([Formula: see text][Formula: see text]g/g) was found at a flow velocity of 200[Formula: see text]m/s and 30∘impact angle with a discharge rate of 2.5[Formula: see text]g/min. While the minimal erosion rate was observed at a low velocity of 150[Formula: see text]m/s, 90∘impact angle, and 5[Formula: see text]g/min discharge rate. Electrochemical polarization studies were carried out on the eroded specimens using a corrosive solution containing 3.5% NaCl. Corrosion potentials and current densities were estimated from polarization graphs using the Tafel extrapolation method. The erosion–corrosion properties of the samples were subjected to metallurgical characterization to evaluate the influence of nichrome plasma coatings to assess the potential causes of failure. The grey relational analysis (GRA) was further used for improving the erosion–corrosion process parameters and found the optimum solution as flow velocity of 150[Formula: see text]m/s, 30∘impact angle with a discharge rate of 5[Formula: see text]g/min. The validation test confirmed an increase of 20–30% in grade when using the optimum process parameters.

Corrosion monitoring for prestressed concrete cylinder pipe spigot with combined use of Tafel extrapolation and surface acoustic wave methods

A novel corrosion monitoring method for prestressed concrete cylinder pipe (PCCP) spigots that combines the Tafel extrapolation and surface acoustic wave (SAW) methods is proposed. Tafel extrapolation and the SAW method are used to determine the self-corrosion rates and output voltage–time curves for a single steel plate and PCCP spigot at different corrosion rates. The mortar coating features a vital anti-corrosion effect on PCCP spigots. Sulfate inhibits chloride rusting of PCCP spigots. For PCCP spigots, normalization based on amplitude is suitable for monitoring the entire rusting process; normalization based on energy is more suitable for early stage monitoring.

Electrochemical corrosion response of ZrN coated Nickel-Titanium alloy in 0.9% NaCl solution

Abstract: The biomedical application as metallic body implants of Nickel-Titanium shape memory alloys are of high interest due to its unique property of pseudo elasticity. However, high content of nickel and its potential to release from the surface due to corrosion raises safety concerns about its allergic reactions, toxicity and carcinogenicity. Hence, it is necessary to produce proper passivity to prevent surface layer degradation. In this study, ZrN coating on Nickel-Titanium shape memory alloys was obtained by vacuum cathodic arc physical vapor deposition technique to improve electrochemical corrosion resistance. The electrochemical corrosion response was studied in 0.9% NaCl solution at 370C using Tafel extrapolation method. Surface morphology was studied using SEM/EDAX and XRD. ZrN coating increases corrosion stability and micro hardness. Keywords: Shape memory alloy; pseudoelasticity; vacuum cathodic arc PVD; electrochemical corrosion; micro hardness.

Improvement of corrosion resistance of galvanization/nickel/chrome plating low carbon steels in H2SO4 under dynamic condition

In this work, the corrosion resistance of metallic coating (ISO 1416) deposited on AISI 1080 low carbon steel has been investigated under static and dynamic conditions (flow rate 30 rpm). The coated steels have been immersed into aqua solution of H2SO4 at 80 °C temperature up to 3 h where pH value 1 is maintained. The corroded surfaces are characterized by SEM, XRD, ATR, EDS and Tafel extrapolation methods. Results show that the corrosion under static condition is higher than that of dynamic condition both for coated and uncoated surfaces. The coated steels exhibit lower corrosion in comparison of uncoated steels. The low carbon steel experiences significant corrosion resistance property in combined effects of dynamic environment and coating surface. Corrosion rate is calculated by following weight loss method. The corrosion damage is remarkably high for low carbon steels. The nickel-plating steel exhibits more corrosion resistance in H2SO4 corrosive medium when comparing with chrome plating steel. On the other hand, chrome plating steel happens more corrosion resistance in comparison of galvanized steel. Besides, lower flow rate makes higher rate of corrosion and lower depth of penetration. It is expected that the outcomes of this work will contribute to the improvement of different concerned mechanical and tribological processes where the corrosion concerning issue.

The Effect of Boron Addition on the corrosion behavior of Ni Cr Modental alloy prepared by powder metallurgy.

The powder metallurgy (PM) method was used to create the alloy. The sintering process was carried out in an inert high-temperature tube furnace in the presence of inert gas at a temperature of 1000 ° C for 8 hours (Argon). In this article, the effect of (B) at three wt.% (0.4,0.8,1.2) on the corrosion rate, hardness, and microstructure of alloys was examined. X-ray diffraction (XRD), open circuit potential, electrochemical tests (Tafel extrapolation method), and Macro hardness Brinell were used to study the effect of adding (B) in various amounts to alloys. Saliva was utilized as the corrosion solution for the testing. The inclusion of the alloy element (B) increased hardness and a decrease in particle size, as seen by the microstructures. Furthermore, the corrosion resistance of the master alloy improved next the addition, as shown by Corrosion potential has increased while corrosion current densities have decreased. The corrosion rate for A, A1, A2 and A3 was 14.50, 7.42, 2.03and 2.77 (mpy) respectively.

Test of inhibitors for preventing corrosion of steel reinforcement in concrete

Abstract Concrete is more widely used than any other manmade material. The objective of this paper is to investigate the behavior of reinforced cement when migration corrosion and guar gum inhibitors are used. The concrete samples were exposed in aggressive media H2SO4 1 M and in the presence of 1∙10-3 M Cl-. Electrochemical measurements such as half-cell potential, polarization resistance and Tafel extrapolation methods were performed in order to obtain information on the corrosion behavior of the reinforcing steel in cement mortar. Results demonstrate high resistance polarization and low corrosion rate for concrete sample with inhibitor. The corrosion rate decreases approximately 95% in presence of locust bean gum and 80% in presence of migration inhibitor.

Effect of low-temperature annealing on the superelastic response and electrochemical corrosion behaviour of equi-atomic Ni-Ti alloy

ABSTRACT Nickel–Titanium (Ni–Ti) alloys have exemplary properties such as good thermo-mechanical response and biocompatibility. Hence, they are one of the prime materials of interest in today’s context for the fabrication of advanced biomedical devices. Such properties can be exemplified with certain techniques such as heat-treatment techniques. However, peer-reviewed literature for the same appears to be inadequate to efficiently quantify the effect of such techniques on the overall performance of such materials. Therefore, the present study focuses on analysing the effect of low-temperature heat treatment on the superelastic behaviour and corrosion resistance of titanium-rich Ni–Ti alloys. The superelastic behaviour has been evaluated for different strains. Meanwhile, the Tafel extrapolation method is incorporated to assess the electrochemical corrosion of these materials. It is noticed that the low-temperature heat treatment has marginal effects on the superelastic behaviour of the alloy. The Ni–Ti alloy annealed at 450°C at 6% predetermined strain rate showed the best enhancement in the superelastic behaviour and the corrosion resistance increased upto treatment temperatures of 350°C. Therefore, the most optimum temperature of annealing is found to be 350°C, resulting in about 35.72% improvement in the corrosion resistance of the alloy when compared to their untreated counterparts.

Effect of Surface Finishing on Microstructure and Corrosion Behavior of Friction Stir Welded Joints For Dissimilar Aluminum Alloys (AA2024-T3 with AA6061-T6)

The aim of this work is to study the possibility of joining two plates from aluminum alloys, AA2024-T3 with AA6061-T6, using friction stir welding (FSW) technique. In this study, the plates were prepared by cutting with dimensions (100 x 50 x 5) mm by CNC milling machine with cutting speed of 1200 rpm and variable feeding speed of (25, 30, 35 & 40 mm/min). The FSW was operated by a vertical milling machine at a rotary speed of 930 rpm and linear welding speed of 30 mm/min to obtain welding joints of dissimilar plates. Microstructure, surface roughness and micro-hardness were examined. Corrosion test was also carried out by electrochemical methods for all specimens in 3.5wt % NaCl solution, and the corrosion rate was calculated by Tafel extrapolation method. The obtained results demonstrated that the feeding speed has a significant effect in decreasing the corrosion rate comparing with the base metal due to the plastic deformation that occurs at high feed speed. The decrease in surface roughness provided more connected between the two contact surfaces that contributed in the refinement of the microstructure. The sample welded at feed speed 40 mm/min offered the optimum results.

ELECTROCHEMICAL PERFORMANCE OF Fe-Cr-Ni ELECTRODE AS CATHODE FOR HYDROGEN EVOLUTION IN KOH SOLUTIONS

Electrocatalytic behavior of commercially available Fe-17Cr-14Ni alloy as a cathodic material for the evolution of hydrogen in alkaline solutions has been characterized by means of microstructural and electrochemical techniques. The microstructure of the alloys was examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. The electrochemical behavior of the examined materials was studied through potentiodynamic polarization techniques and electrochemical impedance spectroscopy (EIS). The effect of electrolyte concentration on the hydrogen evolution reaction (HER) rate and the cathode's electrochemical stability were studied. Tafel extrapolation method was used to determine the kinetic parameters characteristic of the hydrogen evolution reaction. The results show that the investigated alloy can be seen as a good candidate for large-scale and long-term hydrogen evolution. The rate of evolution of hydrogen under low overpotential is relatively high.

Study on the free corrosion potential at an interface between an Al electrode and an acidic aqueous NaCl solution through density functional theory combined with the reference interaction site model

We investigated the free corrosion potential at an interface between an Al electrode and an aqueous NaCl solution (NaCl(aq)) under acidic conditions via density functional theory combined with the effective screening medium and reference interaction site model (ESM-RISM). Firstly, the electrode potentials for the anodic and cathodic corrosion reactions were obtained from the grand potential profile as a function of the electron chemical potential at the interface. Thereafter, we determined the free corrosion potential using the Tafel extrapolation method. The results of the free corrosion potential were consistent with previous experimental data. By controlling the pH of the NaCl(aq), we determined the pH dependence of the free corrosion potential, and the results reasonably reproduce the previous experimental results. Our results indicated that the ESM-RISM method duly described the environmental effect of an acidic solution and precisely determined the free corrosion potential. Therefore, the application of this method presents an efficient approach toward calculating the free corrosion potential for various reactions.

Effect of Martensite Morphologies on Corrosion in 5% H2SO4 Solution of Borided X70 Dual Phase Steel

In the present investigation, some electrochemical properties of dual phase X70 steels with different martensite morphologies which have undergone boriding were studied. To obtain a variety of martensite morphologies, Direct Quenching (DQ), Intermediate Quenching (IQ) and Step Quenching (SQ) heat treatments were applied at an intercritical annealing temperature (IAT) of 760℃. The treatment (DQ) allowed the formation of fine martensite evenly distributed in the ferrite matrix. (IQ) treatment showed the formation of martensite along the ferrite / ferrite grain boundaries. In contrast, treatment (SQ) induced the formation of a banded morphology of martensite and ferrite. The realization of borides on X70 (DP) steel was carried out in a powder mixture containing 5% of B4C as source of boron, 5% of NaBF4 as activator and 90% of SiC as diluent at 950℃ for a period of time from 4 h. The corrosion behavior of X70 (DP) steel has been explored by the Tafel extrapolation method in a 5 wt. % H2SO4 solution. The corrosion resistance of steel which has undergone boriding (BDP) is higher than that of steel which has not undergone it (DP).

Estimation of Corrosion Rate of AISI 1016 Steel by the Analysis of Polarization Curves and Using the Method of Measuring Ohmic Resistance

By the example of the study of AISI 1016 steel corrosion in the HCl solution, the potentialities of various methods for determining the corrosion currents are studied. The corrosion rate of steel without polarization is determined using the method of measuring ohmic resistance of test specimen. It is shown that the iterative method used for the analysis of potentiodynamic curves in the vicinity of corrosion potential avoids the complications that arise when the Tafel extrapolation method is used in the absence of pronounced Tafel sections in these curves.

The role of surface roughness during fretting corrosion of 316L stainless steel

Abstract Fretting corrosion is a synergistic process between the mechanical events and the chemical attack of two contacted surfaces for similar or different alloys. Since implant devices are designed to slide or rotate to perform their function, implant devices may subject to mechanical interaction such as friction, wear damage, together with a corrosive attack as it in contact with human body fluids. The current study focuses on assessing the fretting corrosion resistance of 316L stainless steel (SS) under several applied load (0.5–10) N and grinded surface (400, 600, and mirror finish) grit. The experiment was performed by using a pin on disc technique surrounded by 25 °C Phosphate buffer saline. The morphology, elemental analysis, and resistance to fretting corrosion are investigated by using scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) as well as the Tafel extrapolation method. The results demonstrate that the mirror surface finish gives a lower average fretting corrosion current density value with less debris generation as compared with rougher surface (400 and 600) grit. However, when a high load is applied, the current density seems to be struggling in recovering to the baseline due to the initiation of localized corrosion. The SEM scan clarified the arising of fretting islands. The EDS analysis indicated a high accumulation of chromium and oxygen elements on the fretted area border as compared to the center.

SOL-GEL / DIP COATING TECHNIQUE FOR CORROSION PROTECTION OF PETROLEUM PIPELINE STEEL

In the oil, gas and petrochemical industries the greatest costs are those associated with material failures due directly to corrosive-erosive degradation of surfaces and components of the pipelines. These results in the frequent repair and replacement of parts which accrues costs associated with loss in revenues in downtime and maintenance [1]. In the current study, a dip-coating method was exploited to provide a coating layer of epoxy resin on 316L and 304 stainless steel plate. Epoxy resin was converted to cationic tertiary type amine resin. This cationic epoxy resin, which contains ammonium group in the end of the polymer chain, was synthesized by ring-opening reaction of an epoxy resin with secondary amine in the presence of a proton donor. A layer of resin was successfully deposited on the stainless steel plates and physical properties of the layer were assessed. A detailed study aiming to obtain reliable information of coating properties was carried out. The electrochemical corrosion results showed that epoxy layer has a positive behavior on protections of stainless steels alloys at the early degradation time point. Scanning electron microscopy observation was also used to study the surface morphology before and after coating. Tafel extrapolation method and Tafel slope constants were used to calculate the polarization resistance.

Parameters determining the quality of corrosion damage, induced by impressed current density technique, on steel reinforcement

PurposeIn the present study, an effort has been made to estimate the effect of significant parameters on the vulnerability of steel reinforcement to corrosion, using both impressed current density technique and Tafel extrapolation method.Design/methodology/approachFive sets of tests were performed. Corrosion vulnerability of various diameters, temperature and pH effect on the corrosion process, potential corrosion tendency after a precorrosion period and declination from the theoretical damage prediction model are some of the parameters examinedFindingsThe results of the tests provide useful information on the main parameters, determining the quality of the corrosion damage.Originality/valueThe originality of the present study is the fact that an effort has been made to estimate the effect of significant parameters on the vulnerability of steel reinforcement to corrosion, using both impressed current density technique and Tafel extrapolation method. Interesting conclusions emerged.

Strategies of metal corrosion protection

The present article involves the electrochemical fundamentals of overvoltage/polarization of charge transfer and preceding diffusion, short-circuited corrosion cells, the mixed potential theory underlying submicrocells, differential de-aeration cells, and finally introduction of two methods, namely potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), of determining corrosion current density $$i_{{{\text{corr}}}}$$ and polarization resistance $$R_{{\text{p}}}$$ to make strategies to raise the cathodic hydrogen overvoltage/anodic overvoltage with two examples: a sacrificial anode and a green corrosion inhibitor. Carl Wagner’s pioneering creative work on the mixed potential theory is addressed with particular emphasis that even nowadays constitutes the principle (classical paradigm) of both the linear polarization and the Tafel extrapolation methods. From the critical assessment of corrosion inhibitors, some unexplained questions are extracted and proposed as formidable future challenges to address in the electrochemistry of corrosion inhibition.

The Effect of Bath pH and Temperature on the Corrosion Behavior of Co-Electrodeposited Ni-Cu/Cr2O3 Nanocomposite Coatings

The aim of this work was to assess the influence of pH and temperature of bath plating on the performance of Ni-Cu/Cr2O3 nanocomposite coatings in a corrosive environment. For this purpose, Ni-Cu/Cr2O3 nanocomposite coatings were successfully carried out on the carbon steel by co-electrodeposition method from an aqueous composing of H2O, NiSO4, NiCl, CuSO4, Na3C6H5O7, and H3BO3 with and without 6 g/L Cr2O3 nanoparticles. The microstructure of samples was studied by x-ray diffraction and scanning electron microscopy, and corrosion behavior of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in the 3.5% NaCl solution. It was observed that by increasing the bath pH from 3 to 7 the corrosion current density (icorr) determined by Tafel extrapolation method was changed from 7.4 to 12.5 µA/cm2 and that polarization resistance (RP) obtained from EIS measurements was decreased from 850 to 452 Ω·cm2. The values of icorr and RP were changed from 11.2 µA/cm2 and 514 Ω·cm2 to 6.1 µA/cm2 and 1265 Ω·cm2, respectively, as the bath temperature was varied from 25 to 45 °C. Compared to the Ni-Cu nanocrystalline coating, the value of Rp showed more than 324% improvement when co-electrodeposition of Ni, Cu, and Cr2O3 was carried out at a temperature of 45 °C and pH value of 4.5.

The Effect of the addition of Ta, Zr and in on the corrosion behaviour of CuAlMn alloys prepared via powder metallurgy

CuAlMn-X (X= Ta, Zr and In) shape memory alloy was fabricated using the powder metallurgy (PM) technique. After sintering at 950 °C, the products were processed using two heat treatments (solution heat treatment at 900 °C and aging at 500 °C). The influence of Tantalum (Ta), Zirconium (Zr) and Indium (In) with three wt.% on the mechanicals properties (hardness), corrosion behaviour and microstructure of CuAlMn shape memory alloys was investigated in this paper. The effect of the addition of Ta, Zr and In alloys was investigated using X-rays diffraction (XRD), open circuit potential, electrochemical tests (Tafel extrapolation method) and Vickers micro-hardness. For the corrosion tests, a 3.5 % NaCl (chloride solution) was used as corrosion solution. The results showed that there is an increase in hardness with addition of the alloy element (Ta, Zr and In) and decrease in the size of martensite plate form, as shown in the microstructures. Furthermore, it was found that the corrosion resistance of Cu-Al-Mn after the addition improved, as shown by the increase in the corrosion potential and decrease in the corrosion current densities. The improvement percentage for CuAlMnTa, CuAlMnIn and CuAlMnZr in the corrosion rate was 97 %, 91 % and 77 %, respectively.

Influence of the Thermal Parameters on the Microstructure, Corrosion Resistance and Hardness on the Unidirectional Solidification of Al-10wt% Si-5wt% Cu Alloy

This study aims to correlate thermal parameters in the directional solidification of Al-10wt% Si-5wt% Cu alloy with the resulting microstructure and, in addition, with hardness and corrosion resistance. The results include primary dendritic arm spacing (PDAS),tip growth rate(VL), cooling rate (TR), scanning electron micrographs (SEM), hardness values and corrosion resistance parameters obtained by electrochemical impedance spectroscopy (EIS) and by the Tafel extrapolation method, conducted in 3% (m/v) NaCl solution at room temperature. The results show that coarser PDAS exhibit a tendency to increase in corrosion resistance, except in the positions with higher concentrations of the intermetallic compound Al2Cu, that surrounded by an aluminum rich phase tends to have a higher resistance to corrosion. The hardness values remained constant.

Effect of MoO3 ceramic oxide reinforcement particulates on the microstructure and corrosion behaviour of Al alloy composites processed by P/M route

The corrosion behaviour of Al-MoO3 powder metallurgy processed composites was investigated in this paper. The weight percentage of the molybdenum trioxide was varied as 5, 10 and 15 % to obtain the test samples. The effect of the reinforcement weight percent on the corrosion behaviour was investigated through the Tafel extrapolation method. Furthermore, the effect of corrosion medium temperature i.e. 3.5 % sodium chloride solution on the corrosion behaviour was also studied. The corrosion rates of the composites obtained as a result of polarization experiment through Tafel extrapolation method were checked for its validation. The comparative analysis was undergone with weight loss and solution analysis tests. The corrosion rates derived from the potentiodynamic polarization technique test disclosed that, at both room and elevated temperature of the NaCl solution, the corrosion resistance of the composites improved with the addition of MoO3. This finding was also substantiated by the observance of less surface degradation in the SEM images of the composites incorporated with more MoO3 content. The temperature-induced corrosion behaviour was investigated by immersing in corrosion medium at 27 °C and 80 °C and the elevation of corrosion rate in high-temperature corrosion medium was confirmed. Based on the above results, Al alloys reinforced with MoO3 will be a suitable candidate for heat transfer applications where high erosion-corrosion is encountered in addition to mechanical damage.