Corrosion Behavior Of Metals Research Articles

Study on the mechanism of aluminum melt corrosion of Fe-SG series metals

This paper investigates the corrosion behavior of Fe-SG series metals with different graphite nodule counts to molten Al by using the ultrasonic vibration hot-dip aluminum experimental method. Fe-SG series metals to aluminum melt exhibited a much better corrosion resistance compared to H13 tool steel. As the graphite nodule count increases, the hot melting loss rate of Fe-SG series metals gradually decreases, indicating an improvement in corrosion resistance to aluminum melt. Scanning and EDS analysis of the samples after hot-dip aluminum testing revealed that the thickness of the product layer increased progressively with the extension of hot-dip aluminum time. Through the analysis of the structure and composition of the product layer, it was found that the corrosion products in H13 steel were composed of Fe2Al5 and FeAl3. In addition to the two phases, the product layer of the Fe-SG series metals also contained granularly distributed Fe–Al–Si intermetallic compounds within the Fe2Al5 phase. This resulted in a better corrosion resistance to aluminum melt.

Effect of Cr addition on microstructure, mechanical properties, and corrosion behavior of weld metal in weathering steel of high-speed train bogie

Effect of Cr addition on microstructure, mechanical properties, and corrosion behavior of weld metal in weathering steel of high-speed train bogie

Quantification of Corrosion on Cu Wire Bonding on Ag-Plated Lead Frame in HCl for Automotive Electronic Application

Copper (Cu) wire bonding has been widely used in automotive electronics as an interconnection technology. However, Cu wire bonding faces long-term reliability challenges due to corrosion, particularly when exposed to harsh environments. While the corrosion behavior and mechanisms of bulk-sized Cu metal are well studied, the corrosion behavior of submicron-sized Cu wire bonding in miniaturized components remains unclear. This study investigates the corrosion susceptibility of Cu wire with a 1 mil diameter, bonded to an Ag-plated leadframe in a small-outline transistor (SOT-23) package, commonly used in automotive electronics. The Cu wire bonds were subjected to varying concentrations of hydrochloric acid (HCl), specifically 3 M, 5 M, and 7 M, for exposure durations of 6, 12, and 18 hours. The samples were characterized using a field emission scanning electron microscope to observe the microstructure, and ImageJ software was used to quantify the corrosion of the Cu wire bonds. The findings show that the Cu wire bonding is susceptible to corrosion when exposed to high concentrations of HCl. The corrosion of the microstructure became more severe with increasing HCl concentration and exposure time. The affected area of the Cu wire bonding was 21% after 6 hours of exposure to 3 M HCl, increasing to 100% after 18 hours of exposure to 7 M HCl. This study reveals that the corrosion behavior of Cu wire bonding is a combination of selective and pitting-like corrosion, resulting in localized surface degradation rather than uniform corrosion. These findings provide valuable insights into the corrosion behavior of 1 mil Cu wire bonding in SOT-23 packages under highly corrosive environments.

Research on Metal Corrosion Behaviour of Indirect Air-cooled Circulating Water System

Abstract The indirect air cooling system of an air-cooled power plant consists of a surface condenser and an aluminum radiator. The radiator is usually made of 1050A pure aluminum, and the circulating water pipe connecting the radiator is made of Q235B carbon steel. This article simulates and controls typical water quality parameters such as dissolved oxygen and pH value in indirect air cooling systems using a self-designed simulation device, and studies the influence of various water quality parameters on material corrosion behavior in intercooled circulating water systems when aluminum and carbon steel coexist. The results indicate that factors such as dissolved oxygen, conductivity, pH value, temperature, and redox potential can all affect the corrosion rate of carbon steel and aluminum materials; The increase in temperature and dissolved oxygen leads to an increase in corrosion rate; The main way carbon steel corrodes the system is by consuming dissolved oxygen; The corrosion behaviour in the water circuit will lead to an overall decrease in pH value. In the presence of multiple metals, the influence of iron ions in the solution significantly increases the corrosion rate of aluminum.

Bacterial adhesion and corrosion behavior of different pure metals induced by sulfate reducing bacteria

The corrosion behaviors of four pure metals (Fe, Ni, Mo and Cr) in the presence of sulfate reducing bacteria (SRB) were investigated in enriched artificial seawater (EASW) after 14-day incubation. Metal Fe and metal Ni experienced weight losses of 1.96 mg cm−2 and 1.26 mg cm−2, respectively. In contrast, metal Mo and metal Cr exhibited minimal weight losses, with values of only 0.05 mg cm−2 and 0.03 mg cm−2, respectively. In comparison to Mo (2.2 × 106 cells cm−2) or Cr (1.4 × 106 cells cm−2) surface, the sessile cell counts on Fe (4.0 × 107 cells cm−2) or Ni (3.1 × 107 cells cm−2) surface was higher.

Study on metal corrosion behavior of heat-affected zone of oil pipeline

Due to the influence of welding technology, a series of non-uniform and continuous heat-affected zones formed by welding seams is the weakest link of pipeline steel. Compared with the X70 steel, the heat-affected area is in the form of coarse acicular and massive ferrite, granular bainite, and a small amount of pearlite, with weak strength and corrosion resistance. Therefore, this paper simulated the heat-affected zone of the high-strength steel welding seam by the Gleeble 3500 thermal/force simulation testing machine for two heat cycles. Taking Shengli crude oil as the experimental medium, the metal corrosion morphology of heat-affected zones at different temperatures and transmission rates during hot oil transportation was analyzed through immersion experiment and corrosion morphology characterization. The results show that the increase in temperature and flow rate will increase the overall corrosion rate of the metal in the heat-affected area. In the range of 30∼50°C, pitting corrosion was the main corrosion feature of the metal, and in the range of 50∼70°C, the corrosion morphology of the metal changed from pitting corrosion characteristics to comprehensive corrosion characteristics. In the range of the flow rate studied (1∼4 m/s), the metal in the heat-affected area was mainly the overall corrosion rate, and the metal surface showed the erosion-corrosion characteristics along the flow rate direction.

Impact of water‐in‐diesel emulsion on compression ignition engine's emissions and its challenges—A detailed review

AbstractCompression ignition engines/diesel engines release greenhouse gases like particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), and, unburnt hydrocarbons which pose environmental and human health risks. Water‐in‐diesel emulsion (WiDE) has emerged as a cost‐effective alternative fuel for reducing the emission of these gases in diesel engines. This paper reviews the effectiveness of using emulsion fuel in engines to reduce harmful emissions as well as the challenges associated with WiDE, which include emulsion stability and corrosion. The review is based on available experimental results from various studies in the literature. While there are a few conflicting outcomes among researchers, the majority of results support the benefits of using WiDE in a compression engine as the PM and NOx emissions, significantly decreased. The decrease in NOx is a result of the flame reaching a lower peak temperature during combustion. The reduction in PM occurs as a result of the micro‐explosion process, which enhances combustion efficiency. Even though WiDE significantly reduces the environmental impact of diesel engines, this study also shows that WiDE faces stability problems and enhances the corrosion of materials. The development of a systematic methodology that can accurately measure emulsion stability, the in‐depth study of the impacts of surfactant dosage, water content and temperature on the corrosion behavior of metals in WiDE and also the development of anti‐corrosion intervention suggestions have been suggested based on the analysis of earlier research.

Investigation of kinetics and mechanisms of metallic beryllium corrosion for the management of radioactive wastes

Activated beryllium wastes are produced by the nuclear industry and have to be managed as radioactive waste during decommissioning and dismantling of nuclear facilities. One potential approach to the management of these wastes is their encapsulation and stabilization in cementitious matrices. The main issue with this conditioning is aqueous corrosion, leading to the hydrogen production and potential crack formation leading to a loss of confinement. To evaluate the suitability of different cement formulations, such as Ordinary Portland Cement (OPC) or magnesium phosphate cement for encapsulation of metallic beryllium, the corrosion behaviour of beryllium metal was investigated in solutions with different pHs. In alkaline solutions representative of OPC pore fluids (i.e. NaOH solutions with pH between 12.5 and 14), corrosion rates increase drastically with increasing pH. Investigations of the surface of the corroded beryllium samples by scanning electron microscopy indicate that pitting corrosion is the main corrosion mechanism under these conditions.Graphical abstract

Characteristics and hot corrosion behavior of NiCrAlY metal bonding layers prepared by different processes

The hot corrosion experiments of René N5 alloy coated with three different NiCrAlY metal bonding layers are carried out, that the layers are prepared by different methods (APS, HVAF and MIP). Compared with bare René N5 alloy samples, the hot corrosion resistance of coated samples is improved. It can be attributed to the small internal stress of the surface oxide layer on the coating sample, which is difficult to spall, reducing the degree of hot corrosion reaction. The hot corrosion resistance of NiCrAlY layers is MIP > HVAF > APS, which is positively positively related to the density of layers, because the influence of element diffusion in the process of hot corrosion is effectively slowed down.

Influence of electrochemical descaling treatment in simulated cooling water on the corrosion behavior of stainless steel

The electrochemical descaling treatment of circulating cooling water can effectively reduce the content of scaling ions, chloride ions and produce strong oxidizing substances with bactericidal properties in the water, which is beneficial for operation at high concentration ratio (N) of circulating water, meets the goal of clean production and has a good prospect. However, changes in ion concentration and type in water can have an impact on the corrosion behavior of metals. Currently, there is limited understanding of the impact of electrochemical treatment on the corrosion behavior of stainless steel, a commonly used material in cooling water systems, which increases the application risk of this technology. In this study, the effects of electrochemical treatment of simulated cooling water on the corrosion behavior and the passive film properties of Type 304 stainless steel with different N values were investigated by analysis of water composition, polarization curve and X-ray photoelectron spectroscopy. The results showed that the pitting potential of stainless steel decreased with the raise of N in untreated simulated water, while the pitting potential increased with the raise of N in electrochemically treated simulated water, and the highest pitting potential was observed when N was 10. The electrochemical treatment effectively reduced the Cl− content in the simulated water. With the increase of N, the concentration ratio of [Cl−]/[SO42−] decreased, and the content of ClO− generated by Cl− oxidation in the water increased, which affected the corrosion behavior of stainless steel. Appropriate concentrations of the ClO− can effectively inhibit pitting corrosion of the stainless steel in simulated water, and the best inhibitory effect observed when ClO− concentration was 50 mg⋅L−1. The inhibition of pitting corrosion by ClO− was attributed to the effective improvement of the Cr/Fe ratio and the oxides/hydroxides ratio in the passive film on the surface of stainless steel, thus the compactness and the protection performance of the passive film was enhanced. The results can provide reference for the design of electrochemical treatment devices and processes.

Semi-Quantitative Categorization Method for the Corrosion Behavior of Metals Based on Immersion Test

Corrosion processes are complex in nature and their studies have become an interdisciplinary research field, combining fundamental sciences and engineering. As the quantification of corrosion processes is affected by many variables, standard guidelines to study such phenomena had been developed, such as ASME and ISO, and are broadly used in industry and academics. They describe methods to perform immersion test experiments and to quantify the corrosion rates of metals exposed to corrosive environments, but do not provide any guidelines for post-exposure analysis of the as-obtained corroded samples, which might provide useful information to understand the underlying physicochemical mechanisms of corrosion. This knowledge is useful for selecting optimal construction materials and developing corrosion prevention strategies. In this work, a semi-quantitative categorization method of the corrosion behavior of metals exposed to a corrosive medium based on their mass loss and aspect is presented. For each category, the mathematical aspects of gravimetric measurements of mass change rate and the analytical techniques that can be used for the characterization of materials are discussed. The following method does not intend to replace industrial standards, but to expand them in order to maximize the amount of information that can be extracted from immersion tests.

Corrosion behavior of pure metals (Ni and Ti) and alloys (316H SS and GH3535) in liquid GaInSn

Corrosion behavior of pure metals (Ni and Ti) and alloys (316H SS and GH3535) in liquid GaInSn

Corrosion behaviour of electropolished magnesium materials

Although magnesium and its alloys are promising candidates as biodegradable implant materials, the tendency for localised corrosion mechanism in physiological environment limit their biomedical application. Electropolishing is an attractive strategy for improving the corrosion behaviour of metals, but it is still largely unexplored in magnesium materials. In this study, the characterisation of electropolished surfaces of AM50 and pure magnesium was performed, focussing on their in vitro degradation behaviour in cell medium. Corrosion rates were evaluated using potentiodynamic polarisation. The surface morphology before and after the onset of corrosion was investigated by scanning electron microscopy and confocal laser scanning microscopy. The presented electropolishing process led to improved surface performances, observable by significantly lower corrosion rates (0.08 mm·year−1 in Dulbecco's modified Eagle's medium), lower arithmetical mean height (0.05 µm), lower water contact angle (25–35°) and lower micro hardness (35–50 HV 0.1) compared to mechanically and chemically treated surfaces. MgO/Mg(OH)2 could be detected on electropolished surfaces. The localised corrosion mode could be reduced, but not entirely prevented. Electropolishing shows great potential as post-treatment of magnesium-based components, but detailed tests of the long-term corrosion behaviour are an important area of future research.

Resolving the Dependence of Aluminum Alloy Corrosion on Grain Orientation by Scanning Electrochemical Cell Microscopy

The study of grain-dependent corrosion behaviors of practical polycrystalline metals remains challenging due to the influences of other microstructural features, such as intermetallic particles and grain boundaries. In this work, we employed the oil-immersed scanning electrochemical cell microscopy (SECCM) to investigate the effect of grain orientations of a practical aluminum alloy AA7075-T73 on the surface electrochemical behaviors. Thousands of spatially resolved microscopic potentiodynamic polarization (PDP) measurements were performed, allowing the extraction of information only from grain interior areas excluding intermetallic particles and grain boundaries. The differences in the corrosion behaviors between grains were revealed. Cathodic currents exhibited a strong grain orientation dependence with a decreasing order of {101} > {001} > {111}, agreeing with the prediction from the order of atomic planar density. By contrast, the dependence of anodic currents on grain orientation was weak, and pitting was independent of grain orientation, which could be due to the limited mass transport of ions within the surface oxide film. This work highlights the capability of oil-immersed scanning electrochemical cell microscopy in resolving small electrochemical differences, which will greatly promote the study of grain-dependent behaviors of practical polycrystalline samples.

Investigation of the Effect of Chlorodimethyl Silane on Corrosion Behavior of Zinc Metal

Bu çalışmada çinko metali üzerinde alkol içerisinde klorodimetil silanın farklı derişimlerde (%5, %10, %20) oda koşullarında (25⁰C) karışımları hazırlanarak doğrudan daldırma ile silan filmi oluşturulmuştur. Çinko metali yüzeyinde silan filmi oluşturulması için farklı süreler (15,30,45,60 dakika) kullanılmıştır. En uygun silan filmi oluşturma koşulları belirlendikten sonra çinko metalinin korozyon davranışları yapay yağmur suyu içerisinde incelenmiştir. Bu amaçla AC impedans ölçümleri ve korozyon poatnsiyelleri belirlenmiştir. Oluşturulan silan filminin yüzey morfolojisi hakkında bilgi sahibi olabilmek amacıyla SEM analizleri ve temas açısı ölçümleri yapılmıştır. Sonuç olarak korozyona karşı en dayanıklı elektrotun %10 klorodimetil silan içeren karışıma 60 dakika doğrudan daldırma ile üretilen olduğu tespit edilmiştir

Study on Microelectrochemical Inhomogeneity of an SA508-309L/308L Overlay Welded Joint.

The corrosion behavior of the dissimilar metal welded joint (DMWJ) is highly dependent on its heterogeneous microstructures. However, directly measuring the electrochemical properties of microstructures in different heat-affected zones (HAZs) is a formidable challenge, because traditional bulk electrochemistry can only offer an average signal. Herein, the microelectrochemical properties of an SA508-309L/308L DMWJ were measured in 3.5 wt % NaCl solution using lithography and capillary techniques. Specifically, high-throughput microelectrochemical tests, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP), were conducted on 168 spots (Φ 12 μm). Results revealed five typical EIS responses and seven varieties of PDP curves (different magnitudes of the current density). The maps of thermodynamic and kinetic metrics, such as polarization resistance derived from EIS, corrosion potentials, and corrosion currents extracted from potentiodynamic polarization curves, demonstrated good consistency. The uniform corrosion tendency of the SA508 HAZ subregions during the immersion tests is basically consistent with its Ecorr_avg order of subcritical HAZ (C5, -371 mV) < intercritical HAZ (C4, -546 mV) < fine-grained HAZ2 (C3, -579 mV) < fine-grained HAZ1 (C2, -593 mV). The random presence of inclusions leads to highly heterogeneous microelectrochemical properties of the DMWJ, thereby causing localized corrosion to occur preferentially. Moreover, the macroscopic corrosion behavior is affected by the corrosion products, which display a protective effect that modifies the local electrochemical activity of the SA508 HAZ. The combination of microelectrochemical properties allows for a more comprehensive understanding of the macroscopic corrosion behavior of metals and the galvanic effect between the heterogeneous microstructures.

Study on Corrosion Behavior of Porous Pure Copper Based on Electrochemistry and Scanning Kelvin Probe

Porous metals are widely used in filtration and separation, flame retardant explosion-proof, biomedical application, etc. Compared with its corresponding dense metal, the presence of porous structures also leads to different corrosive performances in porous metal. Some studies have utilized the weight loss method, electrochemical impedance to evaluate porous metal corrosion behavior; however, the influence of pore structure on metal corrosion is still ambiguous, and present methods used for analyses of porous metal corrosion are statistical averages of the corrosion behavior of the entire porous material, which cannot accurately reflect the corrosion behavior inside the pores. Herein, we prepare the porous copper samples with 0, 24, 72, and 96 pores using a mechanical process, and employ scanning Kelvin probe combined with electrochemical polarization and impedance spectroscopy to test the corrosion performance of the porous copper in static and dynamic NaCl solutions. The relevant results indicate that in the static solution, the corrosion resistance of the samples gradually increases with the rise in the number of pores. By contrast, in the dynamic solution, the 24-pore sample is more susceptible to corrosion than the sample without the pore.

An electrochemical method for characterizing the structure of double-layer capacity

PurposeThe relation between metal corrosion behavior and double-layer capacity remains unclear. This study aims to put forward a novel method to measure double-layer capacity.Design/methodology/approachA novel model based on generalized Frumkin–Butler–Volmer equation was put forward. Combining this model with potentiodynamic polarization test and electrochemical impedance spectroscopy, the structure of double-layer capacity can be characterized.FindingsThis study found that the corrosion rate of iron increased with NaCl solution concentration and temperature at the experimental range, but an essential difference existed. The capacity of the diffuse layer and Stern layer increased with temperature and decreased with NaCl solution concentration. The ratio of diffuse layer capacity and Stern layer capacity influences the corrosion rate directly, which can be regarded as one of the judging criteria for corrosion resistance of metal materials.Originality/valueThe convenient means of double-layer structure characterization is still blank. With this method, the corrosion behavior of metal materials can be further analyzed, especially in high-temperature and pressure environments.

Investigating the Effect of Cashew Nut Oil (Anacardium occidentale) Biodiesel on Corrosion of Metals

The transition from fossil fuel to clean and renewable fuel is a burning issue in the global space as at present. In addition to other source of energy, renewable liquid fuels such as biodiesel are providing solution to this surging global need. Just like fossil fuels, these renewable fuels come with their own challenges of which corrosion is prime. In this study the corrosion behaviour of metals in cashew nut oil biodiesel was conducted. Oil extracted from Cashew nuts was characterized for acid value free fatty acid and fatty acid profile. The oil was further trans esterified into biodiesel and fuel properties were characterized. Corrosion test for selected metals in biodiesel using mass loss method was also conducted. The acid value and free fatty acid for the oil was observed to be 5.61 mg/g KOH and 2.26 mg/g KOH respectively. The fatty acid profile was observed to be more of monounsaturated fatty acid especially Oleic acid (68.2 wt %) for biodiesel. The corrosion test showed copper metals and mild steel have higher corrosion rate of 0.02896 mm/y and 0.02617 mm/y respectively. Hence the corrosion pattern of metal in cashew nut oil biodiesel is slightly higher than other edible oil biodiesel.

POSSIBILITIES OF NEUTRON ACTIVATION ANALYSIS FOR STUDYING THE CORROSION BEHAVIOR OF METALLIC MATERIALS IN MOLTEN SALTS

For the BREST-OD-300 reactor facility [1, 2], the technology for evaluating mixed nitride uranium-plutonium spent economical fuel is being determined [3–9]. To separate MNUP SNF from fuel claddings made of materials with high radiation resistance – ferritic-martensitic steel EP-823 [10–16], it is planned to use pyrometallurgical grades of “soft chlorination” [17]. When alloying and impurity elements of steel EP-823 are dissolved in molten salts of eutectic composition based on lithium and potassium chlorides, the melt will be contaminated. For the same reason, the formation of volatile compounds will occur, with their further mass transfer from hot to cold sections of process equipment. When studying the corrosion behavior of metals and alloys in liquid media, the problem often arises of determining small amounts of dissolution products in solution. This problem arises, for example, the rate of dissolution of microimpurities. The sensitivity of the usual, traditional methods used in corrosion testing such as mass loss or colorimetric determination of corrosion products in solution is often insufficient to make appropriate measurements. In these cases, the most effective is the use of the radiochemical method of neutron activation analysis based on. qualitative and quantitative determination of chemical elements, based on the measurement of the radiation characteristics of radionuclides formed during the irradiation of materials with neutrons. This paper presents the results of a study of the corrosion behavior and mass transfer of corrosion products of EP-823 steel pre-irradiated in the IVV-2M research nuclear reactor in molten salts 2KCl–3LiCl and 2KCl–3LiCl–PbCl2 at temperatures of 500 and 650°C for 24 h. It is shown that the method of neutron activation analysis can be used to study the corrosion behavior of EP-823 steel in molten salts of various compositions.