Corrosion Behavior Of Metals Research Articles

Investigation of Electrochemical Corrosion of SS316L in Different Electrolyte

Corrosion is defined as the destruction of metals and alloys by chemical or electrochemical reaction with its environment. The corrosion occurs because of the normal trend of metals to come back to their thermodynamically stable native state. Corrosion cannot be avoided, but it can be controlled and prevented by using suitable methods like cathodic protection, anodic protection, metallic coating, alloying and using inhibitors, etc. Of these, the application of inhibitors reduces the aggressiveness of the corrosive and unsafe aqueous surroundings and preventing the metal and alloy from corrosion by forming a protective layer over the metal surface. The corrosion behavior of stainless steel and other metals in seawater has been studied by many researchers [1-2]. Stainless steels (316L) have been used successfully in many applications in the marine environment. 316L is considered to be one of the most resistant of stainless steel under marine environments, and it has excellent mechanical properties at elevated temperatures and easy fabricability. It is an important structural material for many industrial units, especially the desalination plants. 316L is the most likely candidate for saline environment applications due to their excellent corrosion resistance.The present work was undertaken to study the corrosion behavior of SS 316L metal in different mediums such as Seawater and calcium chloride (Fig. 1) solution by polarization study. The effect of oxygen or air in the electrolyte solution will also be investigated. Corrosion parameters such as corrosion potential, corrosion current, linear polarization resistance, and corrosion rate will be compared and presented in the meeting.

Utilization of biowaste as an eco-friendly biodegradable corrosion inhibitor for mild steel in 1 mol/L HCl solution

This report focuses on the application of a biodegradable biowaste [human hair-(HHR)], to produce a mild steel corrosion inhibitor. The performance of HHR extract in inhibiting metallic corrosion in 1 mol/L HCl was investigated. The analysis of the metal corrosion behavior using electrochemical and weight loss techniques revealed that HHR exhibits an efficient corrosion-mitigating effect via adsorption on the metal surface following a Langmuir isotherm. Tafel-plot results revealed the mixed-mode corrosion protection behavior of HHR. Surface analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy provided evidence for the precipitation of a protective HHR film on the metal surface.

The anaerobic corrosion of candidate disposal canister materials in compacted bentonite exposed to natural granitic porewater containing native microbial populations

AbstractThe materials corrosion test (MaCoTe) is a long‐term, multinational in situ corrosion experiment setup at the Grimsel Test Site, Switzerland. The experiment has been operating since 2014 with a focus on the corrosion behaviour of container materials for the disposal of high‐level waste and spent nuclear fuel under conditions representing a granitic deep geological repository. The experiment consists of eight modules containing metal coupons and bentonite. Two of the modules, each with a different bentonite density, have been retrieved after 394 days of exposure and have been analysed using a range of techniques aimed at studying the corrosion behaviour of the metals and the mineralogical evolution of the bentonite. Weight loss measurements show that carbon steel had a relatively low average corrosion rate (~2 µm year−1). Much lower average corrosion rates were measured for the various types of copper (0.13–0.32 µm year−1). No detectable corrosion was measured on stainless steel coupons. To date, no significant differences were observed in the corrosion behaviour and rate of the test metals in bentonite with different dry densities.

Corrosion Behavior and Morphology of Passive Films Modified with Zinc–Aluminum Simultaneous Treatment on Different Metals

Passive films were formed on A508-3 steel (A508-3), 304L stainless steel (304L) and Incoloy 800 (In800) with blank/zinc/zinc–aluminum treatments in air at 300 °C. The electrochemical corrosion behaviors of different metals were investigated through potentiodynamic polarization, electrochemical impedance spectroscopy and the Mott–Schottky technique. The morphology and composition of passive films were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The zinc–aluminum treatment effectively reduced the corrosion current and increased the impedance of A508-3 and 304L, but had a weak effect on In800. The zinc–aluminum treatment reduced the carrier concentration of A508-3 and changed the semiconductor property of 304L and In800. The order of zinc–aluminum treatment for improving the corrosion resistance of three metals was: A508-3 > 304L > In800. In addition, the zinc–aluminum treatment enhanced the density and smoothness of passive films. According to the composition analysis, spinel ZnAl2O4 was formed on three metals; however, the amount of spinel varied with the content of nickel and chromium in different metals, which affected the results of using this technology.

Scanning Electrochemical Probe Microscopy for Corrosion-Fatigue Manipulation

Corrosion-fatigue is used to describe the weakening of the material resulting from the cyclic loading in a corrosive environment. Understanding this phenomenon reflects on a wide range of electrochemical applications such as hydraulic turbines and gives a better influence on the microstructure defect which by far isn’t clear yet. The ability to investigate the corrosion-fatigue at its point of initiation with a high spatial resolution is believed to manipulate and limit its occurrence on metal surfaces. However, conventional methodologies used are limited to average-base electrochemical studies leaving it insufficient for single-point measurements. Scanning electrochemical probe microscopy, for instance, allows us to map and characterize the corrosion behavior of different metals including its cracking initiation and propagation, at the micro-scale while maintaining a high resolution. Interesting about this technique is its ability to accommodate with non-linear heterogeneous surfaces due to the sewing-needle like microelectrode that moves up and down alternatively without ruining the non-flat superficial. As such, our aim in this project is to exploit the advantages of the SEPM techniques in order to study and monitor the synergistic effect between the fatigue and the corrosion behavior on the surface of some metals.

The impact of Ni on the corrosion behavior and microstructure of weld metal fabricated from E8018-G electrodes

Due to the importance of the weld metal corrosion, this study aims at the effect of using Ni in weld metals on their corrosion parameters and microstructures. In this regard, the effect of negligible amounts of Ni up to 8.0 wt.% is examined on weld metals made of weld electrodes of the E8018-G type in conditions equal to industrial standards. The corrosion parameters of the weld metals are evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy experiments in a corrosive solution of 3.5% NaCl. The morphology of the weld metals is examined using field emission scanning electron microscopy and optical microscopy. Through evaluating the morphology, corrosion current density (Jcorr), corrosion rate (CR), and polarization resistance (RP) of the weld metals containing different amounts of Ni, it is indicated that Ni plays an important role in creating anti-corrosion properties. The microstructure studies indicate that a weld metal containing 2.91 wt.% Ni is homogeneous, and its major phase is acicular ferrite (AF). The results also show that an optimal amount of 2.91 wt.% Ni in a weld metal provides the highest corrosion resistance in a corrosive solution.

Inhibition efficiency of silver nanoparticles solution on corrosion of mild steel, stainless steel and aluminum in 1.0 M HCl medium

Research work on corrosion behaviour of metals and their alloys continues to attract considerable attention because of the huge cost required to prevent corrosion and replace failed or contaminated components due to corrosion reactions. Different inhibitors have been used to minimize corrosion rate, but addition of nanoparticles has been reported to enhance inhibition efficiency. In this work, the influence of silver nanoparticles (AgNPs) on inhibition of corrosion of mild steel, stainless steel and aluminum in 1.0 M HCl were investigated. Biosynthesized AgNPs were acquired from Laboratory of Industrial Nanobiotechnology, Ladoke Akintola University of Technology Ogbomoso. The particles were hitherto characterized using FTIR, UV-Vis and TEM. Five concentrations of AgNPs solution (0, 5, 10, 15, and 20 μg/ml) were added to 1.0 M HCl. The corrosion inhibition effects of the AgNPs on the metal samples were analyzed using gravimetric (weight loss), potentiodynamic polarization and gasometric (hydrogen gasevolution) approaches. Gravimetric study was conducted within 2000 h of exposure, and the results showed that weight loss increased with exposure time but decreased with increased concentration of AgNPs solution. In addition, inhibition efficiency was enhanced by the addition of AgNPs solution; 52% for mild steel, 70% for stainless steel and 62% for aluminum. Gasometric results revealed that the volume of hydrogen gas evolution reduced with increased exposure time and concentration of AgNPs solution. Furthermore, potentiodynamic polarization results showed that the presence of AgNPs modified the mechanism of anodic dissolution and cathodic hydrogen gas evolution. These results indicated that AgNPs can be incorporated into the existing inhibitors towards minimizing corrosion rate.

Comparison of corrosion characteristics of conductive concrete

Conductive concrete has great application potential in grounding and electromagnetic shielding. To verify the effect of conductive concrete on the corrosion of grounded metals, several conductive concrete with different conductive phase, such as Q235 carbon steel, galvanized steel and stainless steel, were prepared. The conductive concrete test specimens are immersed in red soil leachate, their open circuit potential, potentio-dynamic polarization and electrochemical impedance spectroscopy were measured by electrochemical method. Corrosion behaviour of different grounding metals in conductive clays with different conductive phase are compared based on the pre-mentioned three indicators. The results show that conductive concrete can reduce the corrosion of grounded mental effectively compared with ordinary concrete, galvanized steel has better corrosion resistance than Q235 carbon steel, graphite-based conductive concrete can protect the grounding metal better than stainless steel-based conductive concrete, and high conductive phase content can make a low metal corrosion.

The influence of half-cycle rectified sinusoidal alternating current (AC) on corrosion of X80 pipeline steel in an acid bicarbonate solution

PurposeThis paper aims to investigate the effect of alternating current (AC) on corrosion, it is not yet clear about the exact mechanism of the corrosion induced by AC. Previous reports indicated that AC corrosion was similar to the effect of continuous cathodic and anodic polarization on the corrosion process of the metals. Wan et al. studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution.Design/methodology/approachThis study attempted to understand the AC-induced corrosion by imposing the half-cycle AC on the X80 pipeline steel in an acid bicarbonate solution. The AC corrosion mechanism was determined by weight loss and potentiodynamic polarization curve measurements, as well as surface characterization.FindingsThe results show that the positive half-cycle AC accelerated the uniform corrosion in the NaHCO3 solution, the negative half-cycle AC would decrease the uniform corrosion and local corrosion was increased and some Ca and Mg deposited on the surface of X80 steel, so the corrosion rate decreased by negative half-cycle AC. The corrosion product was composed of α-FeOOH under the application of positive half-cycle AC. The oxygen reduction led to a local increase of pH near the electrode surface and led to the formation of α-FeOOH, which enhanced the protectability of corrosion products.Originality/valueResearchers studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution. However, the AC behavior and corrosion mechanism in acid solution are unknown. So to make clear about the corrosion behavior of metals in different polarization states and the mechanism involved, diode technology was used to research the AC corrosion, half-wave AC was applied on the metals after the full-wave rectified.

Corrosion behavior and interaction of mixed bacteria on carbon steel in reclaimed water

At present, the researches on the corrosion of mixed microorganisms pay more attention to iron-oxidizing bacteria (IOB) and sulfate-reducing bacteria (SRB) in tap water or seawater. Pseudomonas fluorescens and Escherichia coli are two common microorganisms in reclaimed water, but there are few studies about their interaction on metal interface and about their influence on metal corrosion behavior. The corrosion behavior of carbon steel under mixed microorganisms of Escherichia coli and Pseudomonas fluorescens was studied by corrosion weight loss, electrochemistry, scanning electron microscopy (SEM) and X-ray diffraction (XRD) in this paper. The dominant bacteria under mixed bacteria conditions determined the final result of corrosion reaction in reclaimed water. On the first three days, the dominant strain was Escherichia coli, which produced acid on the surface of carbon steel and deteriorated corrosion. After the 3rd day, the dominant strain was Pseudomonas fluorescens, which inhibited the growth of Escherichia coli and slowed down corrosion. When the extracellular polymeric substances (EPS) concentration of Pseudomonas fluorescens reached 400 mg/L, it would inhibit the growth and reproduction of Escherichia coli. On the contrary, Escherichia coli EPS acted as a nutrient for Pseudomonas fluorescens, promoting the growth and reproduction of Pseudomonas fluorescens.

Relationship between Microstructure and Corrosion Behavior of Stainless Steel Weld Metals

Relationship between Microstructure and Corrosion Behavior of Stainless Steel Weld Metals

Evaluation of microstructural and mechanical properties of dissimilar Inconel 625 nickel alloy–UNS S32205 duplex stainless steel weldment using MIG welding

Inconel 625 nickel alloy and UNS S32205 duplex stainless steel (DSS) were welded with ER2209 filler metal using MIG (Metal Inert Gas) welding method. The weld metal obtained by DSS filler metal was subjected to mechanical and microstructural evaluation. Toughness and hardness properties had been examined by mechanical and microstructural characterization of weld metal, fusion line, and HAZ (Heat Affected Zone) region, and precipitations were investigated by light microscopy (LM), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). Corrosion behavior of base metals and face and root of weld metal were examined by using potentiodynamic polarization test. Additionally, detailed elemental analysis and mapping of weld metal with both optical emission spectrometer (OES) and X-Ray spectrometer were attained. Results demonstrate a significant decrease in toughness of the welding due to the presence of Nb and Mo rich intermetallic precipitations in the Inconel HAZ and root region, although there is no significant increase in hardness. Potentiodynamic polarization test shows that the dilution-induced microstructural transformation in the root of weld has the worst corrosion resistance in the weld metal. Therefore, this dissimilar welding does not have optimum properties for neither toughness nor corrosion.

Corrosion behavior of X80 steel under disbond coating interfered with AC

Purpose This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method. Design/methodology/approach The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference. Findings The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased. Originality/value This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

Effect of static magnetic field on mold corrosion of printed circuit boards

Mold has a strong impact on the corrosion behavior of metals, especially under environmental conditions conducive to mold growth. However, the magnetic fields generated by electronic devices have effects on the metal corrosion and mold growth. In this study, a 10 mT static magnetic field (SMF) perpendicular to the surface of samples was applied to study the corrosion of a copper-clad printed circuit board (PCB-Cu) by mold under the SMF. Based on the analysis of the corrosion morphology of the PCB-Cu after a test in the atmosphere and the composition of the corrosion products, the corrosion behavior of mold on the PCB-Cu in the presence or absence of the SMF was revealed. In the absence of a magnetic field, mold formed a spore-centered corrosion pit group on the surface of the PCB-Cu, which was macroscopically characterized by regional uniform corrosion. When a 10 mT SMF was applied, the magnetic field exhibited an inhibitory effect on the growth of mold, which was hindered, and the corrosion of the PCB-Cu surface slowed down.

Corrosion Susceptibility of Austenitic Stainless Steels in Direct Carbon Fuel Cell

The direct carbon fuel cell (DCFC) is a future energy technology which is an efficient process for electrical energy generation from carbon-based sources. This technology has an extremely high theoretical efficiency due to favourable thermodynamics of the electro-oxidation reactions in the process. However, several technical challenges exist which must be addressed before the technology can be commercialized. One of the challenges is the corrosion of metal parts in the cell which limits the service life of the unit. In recent year, research on the development of new alloys and surface engineering have been done to address the corrosion issues in molten carbonate fuel cells. However, the literature on the corrosion behaviour of metals in a slurry system (coal + carbonate) is limited. Austenitic stainless steels are known for their high temperature corrosion resistance and excellent mechanical properties. In this work, the corrosion susceptibility of two types of austenitic stainless steels, i.e. 316L (16 wt.% Cr and 10wt. % Ni) and 235 MA (21 wt.% Cr and 11 wt.% Ni) were compared for fuel cell tank body application. The corrosion behaviour of the two stainless steels were evaluated in a slurry, which contained 20 wt% coal and 80 wt% ternary-eutectic (Li2CO3: 43.5 mol%, Na2CO3: 31.5 mol%, and K2CO3: 25.0 mol%), with nitrogen as a sweep gas at 800⁰C was examined for a 30-day period. The results indicate that the weight gain (due to corrosion product build-up) for both the stainless steels was marginal after 7 day exposure, i.e., 0.4% and 0.5% for 316L and 253 MA, respectively. However, after 30 days exposure, the weight gain increased to 0.98% for 316L, whereas for 253MA the weight gain remained at ~ 0.5%. Thus, the study suggest that 235 MA stainless steel is superior to 316L stainless steel in the coal-carbonate slurry environment. The corrosion mechanisms of the stainless steels will be discussed in the presentation.

Corrosion Behavior of Common Metals in Eutectic Ionic Liquids

Corrosion Behavior of Common Metals in Eutectic Ionic Liquids

The corrosion behaviour of as-welded and post-weld heat treated Ti6Al4V alloy in simulated body fluid

In this study, the corrosion behavior of Ti6Al4V alloy base metal, laser welded and post-weld heat treated (PWHT) samples in simulated body fluid was investigated. The potentiodynamic polarization curves of the as-welded and PWHT samples were compared with each other and with the base metal. Surface morphologies of samples were evaluated. The polarization curves indicate that, the lower corrosion resistance obtained for as-welded samples as compared to base metal. The corrosion resistance of welded joints improved with increasing welding speed. PWHT process has positively affected to the corrosion properties of the laser welded Ti6Al4V joints.

Corrosion behavior of metal–composite hybrid joints: Influence of precipitation state and bonding zones

The corrosion behavior of AA2024-T3/carbon-fiber-reinforced polyphenylene sulfide joints was investigated. The joints were exposed to salt spray from one to six weeks. The residual strength of these joints was assessed using lap shear test. The corroded surfaces and interfaces were analyzed using small angle X-ray scattering, scanning electron microscopy, and energy dispersive spectroscopy. Regarding the top surface of the joints, the aluminum part corroded preferably in the heat-affected zone (HAZ). It was demonstrated that the HAZ is more susceptible to corrosion than the stir zone (SZ) due to the anodic sites formed by coarse intermetallic particles and S’(S) phase precipitation. Besides, the macro-galvanic coupling between the zones may also potentialize the corrosion in HAZ as the base material and SZ displayed a lower volume fraction of S’(S) than HAZ. In addition, the corrosion at the interface of the joints was evaluated. Four different stages in the development of corrosion at the interface were identified. At Stage I, the joints showed fast strength degradation (0% to -24% of ultimate lap shear force (ULSF) due to water absorption and NaCl migration into the composite. At Stage II, the strength degradation of the joints was stalled (-24% to -28% of ULSF) due to the protection provided to the bonding area by the reconsolidated layer of polymer at the borders of the joint. The polymeric layer acted as a protective coating on the aluminum surface. At Stage III, the corrosion overcame the polymeric layer by reaching the bonding area of the joint. As a result, the strength of the joints rapidly degraded from -28% to -44% of ULSF. Finally, at Stage IV, one expects generalized corrosion in the bonding area, leading to the final strength degradation of the joint.

Influence of Cu Content on Microstructure and Corrosion Behavior of Flux-Cored Arc-Welded Metal with 10CrNi3MoV Steel

Influence of Cu Content on Microstructure and Corrosion Behavior of Flux-Cored Arc-Welded Metal with 10CrNi3MoV Steel

Corrosion behavior of base metal and weld bead of CLAM steel in flowing Pb-Bi at 550 °C

Corrosion behavior of base metal and weld bead of China low activation martensitic (CLAM) steel was studied in the flowing Pb-Bi at 550 °C. The corrosion tests were performed in an apparatus which was designed and manufactured by ourselves and could simulate the condition of corrosion test in the nuclear industry. CLAM steel is one of the reduced-activation ferritic/martensitic steels (RAFM) that is widely considered as the candidate structural metal for the new generation nuclear facilities. The flow velocity, corrosion temperature and corrosion time were 2.98 m/s, 550 °C and 1500 h, respectively. The corrosion test results indicate that a double-layer oxide film consisted of Fe3O4 outer layer and (Fe,Cr)3O4 inner layer on surface of all the samples. The corrosion process of base metal and weld bead of CLAM steel in flowing liquid Pb-Bi included the oxidation-corrosion and erosion. The degree of oxidation-corrosion and erosion on the surface of the weld bead samples was more serious than that on the surface of the base metal, due the small grain size was related to greater corrosion resistance. The corrosion test results will provide a reference for the feasibility of the practical application of CLAM steel in the field of nuclear power in the future, and they will also provide data support for estimating the actual service life of CLAM steel.