Galvanic Corrosion Behavior Research Articles

Numerical Simulation of Galvanic Corrosion between Carbon Steel and Low Alloy Steel in a Bolted Joint

The galvanic corrosion of a bolt joint combining carbon steel end plate and low alloy steel bolt was investigated electrochemically in a 1 M HCl solution. The corrosion parameters of the joint components were used for numerical simulation using Comsol Multiphysics software to analyze the galvanic corrosion behavior at the contact zone between the head bolt and the end plate. In this research work we evaluate the variation of the corrosion rate in the steel end plate considered as the anode, in order to determine the lifetime of the bolted assembly used in steel structures. Three materials (20MnCr5, 42CrMo4, and 32CrMoV13) and three bolts (M12, M16, and M20) were tested in two thicknesses of electrolyte 1 M HCl (e = 1 mm, e = 20 mm). It is found that the corrosion rate of the anode part (end plate) is higher for 32CrMoV13 materials and it increases if both diameter of the bolt and thickness of the electrolyte increase (Cr(M20) > Cr(M16) > Cr(M12) and Cr(e = 20 mm) > Cr(e = 1 mm)). This corrosion rate is higher in the contact area between the bolt head and the end plate, and it decreases if we move away from this contact area.

Galvanic corrosion behavior of plain carbon steel-B4C composite in 3.5% NaCl solution with electrochemical noise

The galvanic corrosion behavior of metal-matrix composite plain carbon steel/boron carbide (B4C) in 3.5% NaCl solution was studied. The composite was locally produced as a weld band on carbon steel by means of the gas tungsten arc welding process and using nickel as the wetting agent. Samples from the weld band, heat-affected zone and parent metal region were extracted precisely and DC/AC electrochemical tests in combination with techniques such as scanning electron microcopy and energy dispersive spectrometry were conducted. The results of the electrochemical tests show that the corrosion resistance of the parent metal sample is higher than that of the welded composite and the HAZ samples. However, as the corrosion potential (ECorr) of the parent metal is more positive than other two samples, this becomes the cathode in galvanic couples with two other samples. On the other hand, the weld composite sample is also cathodic due to its more positive ECorr compared to HAZ sample. This means that the HAZ can be particularly at risk of preferential dissolution. The approach can be used in specific areas on plain carbon steel to locally increase hardness and resistance to abrasion and reduce manufacturing costs.

Galvanic Corrosion Behavior of Aluminum Alloy (2219 and ZL205A) Coupled to Carbon Fiber-Reinforced Epoxy Composites

Galvanic Corrosion Behavior of Aluminum Alloy (2219 and ZL205A) Coupled to Carbon Fiber-Reinforced Epoxy Composites

Modeling the galvanic corrosion behavior of Pd[sbnd]Cu couple used in hydrogen purification – PEM fuel cell hybrid systems

Modeling the corrosion behavior of Pd/Cu couple in acidic media (0.25 M HCl) at various operating conditions [(30, 50 °C) and (0, 300, 600, 900 RPM)] was considered as an ultimate goal of this work. Multiple regression analysis with respect to ANOVA was utilized to generate a mathematical correlation. The derived correlation and the surface response revealed that increasing temperature and speed of agitation affected the corrosion rate of Cu in the Pd/Cu couple. This result indicates that using copper in the hydrogen purification – Proton Exchange Membrane (PEM) fuel cell hybrid systems is not acceptable due to the degradation that might occur as a direct result from the galvanic action between Pd/Cu couple. In order to improve the resistance of Pd against corrosion and hydrogen embrittlement at elevated temperatures, it should be alloyed with Au or Ag rather than copper.

Electrochemical Properties of Oxide Films on Ti

Introduction Titanium has high corrosion resistance due to existence stable passive film on its surface. Moreover, titanium has biocompatibility and high mechanical strength. Therefore titanium can be used for biomaterial. Not only I generate it by oneself get oxide film to maintain superior corrosion resistance When I use titanium at a practical use stage, but also may put making oxide film before the use. Particularly, it is concerned about corrosion being promoted because a function, a property of the titanium surface changes progressively when a point varying in thickness and the property of a formed film exists. The factors affect in corrosion of metallic material present in the human body. The chloride ion has been performed so far. However there are few reported cases of the influence that the density of NaCl gives to corrosion behavior of titanium. Therefore the influence of the surface film was evaluation by measuring the current which the catalytic current measurement was performed, and drifted between titanium having a variety of surface. In addition, using the aluminum and zirconium as a comparison 2. Experimental Methodology 2.1 Polarization curves measurement The sample ware polished titanium, aluminum and zirconium. Test solution was 0.1M NaCl solution. The solution temperature was ambient temperature, and in atmosphere. The potential of the 1800 seconds after dipping start was immersed potential. Counter and the reference electrode was Pt and silver/silver chloride/saturated KCl electrode, respectively. Shifted the potential from the immersion potential to 1.0V. Shift the potential speed was 1mV/s. 2.2 Galvanic corrosion conditions The samples ware prepared from tow kind of titanium. The first sample was bare titanium which was polished with emery paper. The second sample was titanium which was treated by anodic oxidation treatment. Test solution was 0.1M NaCl solution. The solution temperature was ambient temperature, and in atmosphere. As boric acid anodized – performs 3600s between and polarization at constant potential in a sodium borate buffer solution (pH8.4), to prepare an oxide film on the titanium. Setting potential was 2V, 5V, and 9V. The titanium anodized(titanium(A)), was immersed in 0.1M NaCl in conduction with titanium immediately after the mechanical polishing(titanium(P)), 3600s measuring temporal changes of the current flowing between them. I also was measured for the current flowing between the sample of titanium(P)titanium(P)for comparison. 3. Result 3.1 Polarization curves measurement Which sample also nonconductor area has been confirmed.In addition, non-conductor current density was about the same. However, since the aluminum and zirconium sharp rise in current density could be confirmed, it considered to corrosion is occurring. Aluminum rose in current density at lower zirconium potential was confirmed. Titanium increase in current density in the measuring range could not be confirmed. From this result Ti has most safety oxide film. 3.2 Galvanic corrosion conditions Galvanic corrosion behavior of titanium different oxide film state in 0.1M NaCl solution was evaluated. In any Conditions the micro-cell observation results show the current flows immediately after immersing. However, the current density shifts to approaching zero value and does not flow significantly after a period time. It can be explained that there is no formation of micro-cell due to passive film after some period time. the effect of anodic oxidation treatment was also observed. The corrosion resistance of the treated sample decreased which was indicated by higher current density in the starting immersion. Moreover, after several time period the current density of the treated sample was still higher than bare titanium even though in small value. 4.Conclusion ・Ti made stability passive film over a wide potential in NaCl Solution. ・The different thickness or the properties of the passive film of Ti, which condition did not make micro-cell. ・In the process about 3600 seconds oxidation in NaCl solution, the effect of Ti was disappeared.

Galvanic Corrosion of AA5052 Aluminum-Magnesium Alloy and Carbon Steel in NaCl Solutions

Aluminum alloys (AAs) such as 5000 and 6000 series, which show relatively good corrosion resistance and plastic workability, have been utilized to automobile body parts for reducing the weight of the body and for the improvement of fuel consumption. However, since the body parts made of Al alloys should be joined with steel parts by welding or other methods and the joined parts can be exposed to atmospheric corrosion environments, there has been a concern about degradation of the parts due to galvanic corrosion between Al alloy and steel. In this study, galvanic corrosion behavior of AA5052 aluminum-magnesium alloy and SS400 carbon steel is investigated in NaCl solutions. A galvanic couple used in this study consisted of AA5052 Al-Mg alloy (Mg: 2.65, Si: 0. 08, Fe: 0.27, Cu: 0.01, Cr: 0.17, Zn:0.01, Al: bal. (mass%)) and carbon steel (JIS SS400). Both materials were 15-mm-square plates of 3 mm in thickness. After lead wire was connected on the surface of the plates, they were embedded in an epoxy resin. At this time, both materials were separated with a 500-um gap. The surface of the galvanic couple was polished with SiC papers down to JIS 2000 grit and rinsed in EtOH. Galvanic corrosion experiments were done in aqueous NaCl solutions of various concentrations ranging from 5 mM to 500 mM. Galvanic current and corrosion potential of the couple were measured during the immersion in the solutions. When a galvanic couple was immersed in a NaCl solution, galvanic current decreased gradually with immersion time and reached almost a constant value. On the other hand, corrosion potential for the galvanic couple showed complex behavior with immersion time. Just after immersion, the corrosion potential decreased in the less noble direction, which may be due to the initiation of corrosion of AA5052, and then after reaching the minimum value, the corrosion potential started to increase to a noble potential. Although the corrosion potential and the magnitude of the galvanic current were different depending on the concentration of the NaCl solutions, they did not change in a regular manner as a function of the NaCl concentrations. The changes in the corrosion potential and the galvanic current may be related to the transition of anodic dissolution behavior of AA5052 in the NaCl solutions of different concentrations.

Galvanic corrosion behaviour of HE 20 / MDN 138 & HE 20 / MDN 250 alloys in natural seawater

In view of their excellent mechanical properties, workability and heat treatment characteristics, MDN 138 & MDN 250 have been widely used in missile, rocket and aerospace industries. With light weight and high performance characteristics HE 20 aluminium alloy acts as an important material in defence and aerospace applications. The galvanic corrosion behaviour of the metal combinations HE 20 / MDN 138 and HE 20 / MDN 250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI’s Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN 138, MDN 250 and HE 20 of the individual metal, the mixed potential and galvanic current of the couples HE 20 / MDN 138 and HE 20 / MDN 250 were periodically monitored throughout the study period. The calcareous deposits on MDN 138 and MDN 250 were analysed using XRD. The results of the study reveal that that HE 20 has offered required amount of protection to MDN 138 & MDN 250.

Investigation of Galvanic Corrosion Behavior of Dual Phase Steel

Dual phase steels have been widely used in the automotive industry to produce lighter weight vehicles to meet stringent safety and fuel economy regulations. While galvanic corrosion resulting from dissimilar ferrite and martensite phases has been reported, little is known about the corrosion behavior of dual phase steel coupled to a dissimilar metal under corrosive environments. A fundamental study was undertaken to understand the corrosion behaviors of dual phase steel under coupling conditions in NaCl solution. The results show that dual phase steel has a corrosion potential between carbon steel and martensitic steel. Galvanic action between the ferrite and martensite phases leads to selective corrosion of ferrite phase in NaCl solution. When coupled to more noble Ni, dissolution takes place in both ferrite and martensite phases, and ferrite phase dissolves faster. When coupled to less noble Zn, a minor amount of hydrogen resulting from corrosion of a steel-Zn coupling is found to diffuse into the steel.

The monitoring of galvanic corrosion behaviour caused by mineral deposit in pipeline working conditions using ring form electronic resistance sensor system

In this paper, a ring form electronic resistance (ER) sensor system was developed for the study of under-deposit corrosion (UDC) caused by mineral deposit in pipeline conditions. The corrosion status of different locations along the pipeline circle direction and the galvanic current between the deposit-covered area and the bare steel area were monitored by the conjunction of the ER method and electrochemical noise technique. The performance of inhibitor ethylene diamine tetra methylene phosphonic acid sodium (EDTMPS) on UDC was studied by both the electrochemical method and the ring form ER sensor system. The measurement results demonstrated that the inhomogeneous distribution of the rust layer will cause heterogeneous corrosion patterns in the pipeline. Though EDTMPS showed an excellent inhibition effect for the corrosion of both deposit-covered steel and bare steel in electrochemical tests, it failed for the inhibition of UDC in the pipeline working conditions and serious localised corrosion beneath the sand particle was monitored by the sensor system.

Galvanic corrosion behaviour of iron coupled to aluminium in NaCl solution by scanning eectrochemical microscopy

Scanning electrochemical microscopy (SECM) was used to sense the concentration of ions in 0.1M NaCl aqueous solution at the iron-aluminium couple. The SECM measured the concentration of ions relevant to the corrosion processes. The electrochemical behaviour of galvanic Fe/Al coupling was investigated as a function of time using SECM microelectrode tip. SECM amperometric line scan curves were obtained over the Fe/Al at a constant distance. In the first case the chemical species participating in the corrosion reactions at the sample are detected at the SECM-tip by applying appropriate potential values to the microelectrode. The release of Al3+ into the solution from local anodic surface, as well as the consumption of dissolved oxygen at the corresponding cathodic surface was successfully monitored. The results revealed that the galvanic couple where Fe/Al is close to each other will show lower corrosion rate due to the formation of corrosion products on the metal surface with further increase in exposure times.

Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM

The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM) was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS) measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 M NaCl, corrosion occurred at the braze-316L interface preceded by preferential dissolution of the Cu-rich phase within the braze alloy. Braze corrosion was driven by galvanic couples between the braze alloys and stainless steel as well as between different phases within the braze microstructure. Microgalvanic corrosion between phases of the braze alloys was investigated via SKPFM to determine how corrosion of the brazed joints developed.

Investigation of Galvanic Corrosion Behavior of Dual Phase Steel

Dual phase steel has been widely used in the automotive industry to produce lighter weight vehicles to meet stringent safety and fuel economy regulations. One potential concern with dual phase steel is galvanic corrosion when it is exposed to a corrosive environment. In dual phase steel, the dissimilarity in chemical composition and lattice structure could induce different corrosion potentials between the ferrite and martensite phases. As a result, microscopic galvanic couplings could be formed between ferrite grains and their neighboring martensite grains. In this study, the corrosion behaviors of three commercial steel grades: carbon steel, martensitic steel and dual phase steel, are investigated with a variety of electrochemical and surface analytical techniques to understand the mechanism of galvanic corrosion of dual phase steel. The corrosion potential of each steel grade is determined with potentiodynamic technique when the steel is exposed to sodium chloride (NaCl) solution. The study shows that the corrosion potential of dual phase steel is an intermediate between martensitic and carbon steels. In a galvanic coupling of carbon steel/ martensitic steel, carbon steel is found to corrode to protect martensitic steel when exposed to NaCl solution. Examination of dual phase steel after immersion in NaCL solution for an extended period of time indicates the occurrence of galvanic corrosion in the dual phase steel. The corrosion is found to occur primarily in the ferrite phase of dual phase steel.

Effect of Temperature on the Galvanic Corrosion of Cu-Ni Alloy/High Strength Steel in Seawater

The galvanic corrosion behavior of Cu-Ni Alloy(B10)/high strength steel (921A) has been studied using a zero-resistance ammeter (ZRA) in seawater at different temperatures. As well as it was systemically investigated by weight loss measurements, electrochemical methods and scanning electron microscope.Results showed 921A acts as the anode and B10 act as the cathodes. The effect of temperature on the galvanic corrosion is important, the corrosion rate became higher with the temperature increased.

Galvanic Corrosion between Alloy 690 and Magnetite in Alkaline Aqueous Solutions

The galvanic corrosion behavior of Alloy 690 coupled with magnetite has been investigated in an alkaline solution at 30 °C and 60 °C using a potentiodynamic polarization method and a zero resistance ammeter. The positive current values were recorded in the galvanic couple and the corrosion potential of Alloy 690 was relatively lower. These results indicate that Alloy 690 behaves as the anode of the pair. The galvanic coupling between Alloy 690 and magnetite increased the corrosion rate of Alloy 690. The temperature increase led to an increase in the extent of galvanic effect and a decrease in the stability of passive film. Galvanic effect between Alloy 690 and magnetite is proposed as an additional factor accelerating the corrosion rate of Alloy 690 steam generator tubing in secondary water.

Effect of Silane on Galvanic Corrosion between EW75 Magnesium Alloy and TC4 Alloy

Abstract Silane treatment has good corrosion resistance to protect magnesium. In order to delay the galvanic corrosion of Mg-7Gd-5Y-Nd-Zr rare earth magnesium alloy (EW75) and Ti-6Al-4V alloy (TC4), using self corrosion magnesium alloy as the contrast group, the galvanic corrosion behavior of magnesium alloy modified with and without silane coupled with TC4 alloy were investigated. The surface morphologies of magnesium alloy after immersion in NaCl solution for 48 h were examined with digital photography and scanning electron microscopy (SEM). And the self corrosion current density and the galvanic corrosion current density of the specimens were characterized by polarization and galvanic corrosion tests, respectively. The results show that silane film can reduce the weight loss rate of Mg alloy, and transform local pitting corrosion into uniform corrosion, and the magnesium alloy with silane pretreatment has better galvanic corrosion resistance compared with as-received Mg alloy. It can be explained that silane film can improve the potential of magnesium alloy and reduce the galvanic corrosion current density.

Galvanic Corrosion Behavior of Two Stainless Steels in Simulated Muffler Environments

The cyclic method of hot air oxidation/immersion in condensates was adopted to simu- late the internal service conditions of automotive mufflers. The galvanic corrosion between type 409 and 304 stainless steels was investigated during the condensates immersion by using electro- chemical measurements. The results of coupling potential and current indicate that the galvanic cor- rosion effect is very weak between these two steels without suffered from hot air oxidation. This means that 304 stainless steel can hardly accelerate the corrosion of 409 stainless steel as they con- tact directly in the condensate solutions. During the cyclic tests, the two steels show relatively high- er values for the coupling current in the low coupling potential cases. Hot air oxidation will en- hance the galvanic corrosion tendency between the two steels. However, they show small coupling current densities after cyclic oxidation at 250 ℃, with weak galvanic corrosion effect between them. Whereas they display large coupling current densities (i.e. strong galvanic corrosion effect) with the occurrence of localized corrosion after cyclic oxidation at 400 ℃.

Galvanic Corrosion Behavior of Couples of Hot Rolled Steel SS400 and Cold Rolled Steel ST12 with Two Coatings

Galvanic corrosion behavior of couples of cold rolled steel SS400 and hot rolled steel ST12 with chrome-free Zn/Al coating or Zn/Ni alloy electroplating was studied in 3.5%NaCl (mass fraction) solution by means of potentiodynamic polarization and galvanic method. The results showed that the couple of SS400 and ST12 with Zn/Ni alloy electroplating exhibited a weaker ten- dency of galvanic corrosion, a higher open circuit potential and a smaller galvanic current rather than that with chrome-free Zn/Al coating. While the free-corrosion current of Zn/Ni alloy electro- plating coating was smaller than that of Zn/Al coating. Therefore, Zn/Ni alloy electroplating is ex- tremely promising coating for the auto-mobile fastener to replace the traditional Zn electroplating.

Galvanic corrosion behaviour of carbon fibre reinforced polymer/magnesium alloys coupling

The galvanic corrosion behaviour of carbon fibre reinforced polymer (CFRP, T300/648) in contact with different magnesium alloys (AZ31, LZ91 and LZ141) in a sodium chloride solution and the influence of micro-arc oxidation (MAO) film on the corrosion behaviour of CFRP/magnesium alloys coupling were investigated using the electrochemical method. The results showed that the galvanic activity of CFRP/magnesium alloys coupling increased with the increase of lithium concentrations. The duration of the inhibitory effect of MAO film on the corrosion of CFRP/Mg–Li coupling is longer than that of CFRP/Mg–Al coupling due to its double-layer structure.

Effect of Heat Treatment on Galvanic Corrosion of Cu/Al/Cu Clad Soaked in 3.5% NaCl Brine Solution

The galvanic corrosion of Cu/Al/Cu clad in 3.5% NaCl brine solution has been studied. No visible intermetallic compounds were found at the Cu/Al interface after roll-bonding, But Intermetallic layer grew up to 40μm after heat treatment 500°C for 10hours. The galvanic corrosion occurred significantly in the Al region in contact with Cu. The depth of the dissolved Al gradually decreased with distance away from the Cu/Al interface. Both IDR width and IDR depth increased steadily with increase of soaking time. The IDR width and depth of as-roll-bonded Cu/Al/Cu is far greater than those of heat-treated Cu/Al/Cu at 500°C for 10hours, suggesting the presence of intermetallic compounds influences the galvanic corrosion behavior.

The Influence of Temperature on the Galvanic Corrosion in Multi-Material System in Seawater

The galvanic corrosion behavior of titanium (TA2)/Cu-Ni alloy (B10)/low alloy steel (921A) multi-material system has been studied using a zero-resistance ammeter (ZRA) in seawater at different temperatures. After the tests, the surface morphologies of the samples were detected by SEM. Results showed galvanic corrosion behavior of TA2/B10/921A fulfill the mixed potential theory, 921A acts as the anode and both TA2 and B10 act as the cathodes. The effect of temperature on the galvanic corrosion is important, the corrosion rate increases with increasing temperature.