Higher Corrosion Rate Research Articles

Single step calcium sulfate scale removal at high temperature using tetrapotassium ethylenediaminetetraacetate with potassium carbonate

Calcium sulfate (CaSO4) scale has been identified as one of the most common scales contributing to several serious operating problems in oil and gas wells and water injectors. Removing this scale is considered an economically feasible process in most cases as it enhances the productivity of wells and prevents potential severe equipment damage. In this study, a single-step method utilizing potassium carbonate and tetrapotassium ethylenediaminetetraacetate (K4-EDTA) at high temperature (200 °F) has been used to remove CaSO4 scale. The CaSO4 scale was converted to calcium carbonate (CaCO3) and potassium sulfate (K2SO4) using a conversion agent, potassium carbonate (K2CO3), at a high temperature (200 °F) and under various pH conditions. Various parameters were investigated to obtain a dissolver composition at which the optimum dissolution efficiency is achieved including the effect of dissolver pH, soaking time, the concentration of K4-EDTA, the concentration of potassium carbonate (K2CO3), temperature impact and agitation effect. Fourier transform infrared, X-ray crystallography, ion chromatography, stability tests and corrosion tests were carried out to test the end product of the process and showcase the stability of the dissolver at high temperature conditions. A reaction product (K2SO4) was obtained in most of the tests with different quantities and was soluble in both water and HCl. It was observed that the dissolver solution was effective at low pH (7) and resulted in a negligible amount of reaction product with 3 wt% CaSO4 dissolution. The 10.5-pH dissolver was effective in most of the cases and provided highest dissolution efficiency. The reaction product has been characterized and showed it is not corrosive. Both 7-pH and 10.5-pH dissolvers showed high stability at high temperature and minimum corrosion rates. The single step dissolution process showed its effectiveness and could potentially save significant pumping time if implemented in operation.

Assessment of Hot Corrosion in Molten Na2SO4 and V2O5 of Inconel 625 Fabricated by Selective Laser Melting versus Conventional Technology.

Inconel 625 samples, obtained by Selective Laser Melting (SLM) and conventional technology, were tested for hot corrosion resistance against a molten mixture of Na2SO4 and V2O5. The assessments were performed in air, at 900 °C with exposure time of up to 96 h, and at 1000 °C for 8 h. Weight gain was higher for samples obtained by SLM, with 37.4% after 8 h, 3.98% after 24 h, 4.46% after 48 h, and 5.8% after 96 h at 900 °C (22.6% at 1000 °C, 8 h). Three stages of corrosion were observed, the first and last with a high corrosion rate, while the second one showed a slower corrosion rate. Corrosion behaviour depends on the morphology of the grain boundary, which can influence the infiltration of corrosive salts, and on the formation of Cr2NiO4 compound, which acts as a temporary barrier.

High-temperature corrosion in a multifuel circulating fluidized bed (CFB) boiler co-firing refuse derived fuel (RDF) and hard coal

In this work samples of corrosion products collected from waterwalls made of P235GH and 16Mo3 steel are investigated. The samples originated from a full-scale circulating fluidized bed (CFB) boiler co-firing refuse derived fuel (RDF) with hard coal. The samples were analyzed using SEM-EDS technique to determine the composition and distribution of corrosion products. Two types of corrosion spots were distinguished: these rich in chlorine and potassium (up to 46.6% and 26.3%, respectively) and these rich in chlorine and sodium (up to 47.7% and 34.8%, respectively). Moreover, laboratory corrosion tests were performed to determine the corrosion characteristics at 510 and 410 °C and to investigate the influence of fuel additives on corrosion rates. High contents of chlorine (5.07%) and sodium (5.58% of Na2O) in RDF ash together with high potassium content (4.34% K2O) in coal ash resulted in high corrosion rate. To mitigate this unwanted effect, additives such as halloysite, kaolin and sulfur were tested and halloysite was proven to be the most effective. The oxide scales formed on the steel within deposits varied in terms of thickness, structure and porosity. It was found that the porosity and adhesion of the oxide layer play a key role in the corrosion process.

Evaluation of corrosion and scaling potentials of oilfield waters in an offshore producing facility, Niger Delta.

In this study, water samples from Miocene reservoirs, offshore Niger Delta, and seawater samples used for water injection were investigated in an attempt to examine the chemistry, evaluate the corrosion behaviour of steel, iron, and aluminium in different aqua media, and evaluate the scaling potentials of the oilfield produced waters (OFPW). Chemical analyses of the waters were determined; corrosion rate measurements were carried out by the weight loss method at room temperature while corrosion kinetics was carried out using conventional methods. Langelier saturation index (LSI), Ryznar stability index (RSI), Larson-Skold index (L-S), Puckorius scaling index (PSI), and aggressiveness index (AI) were evaluated for assessing the corrosiveness and scaling potential of the formation waters, using water quality data. The magnitude of corrosion of these metals was studied for an exposure period of 42 days. Chemical analysis revealed that the waters are slightly alkaline and generally classified as hard, saline water of the Na-Cl type based on its total dissolved solids (TDS). Produced water pH values range from 7.32 to 8.38. Results showed the likelihood of some of the water to form mild to severe scales based on the corrosivity indices, while the seawater samples are classified as 'non-aggressive' and 'aggressive'. Steel has the highest corrosion rate with a value of 3.84 × 10-3 mg cm-2 h-1 compared to aluminium with the lowest rate of 0.37 × 10-3 mg cm-2 h-1. In most cases, the rate of corrosion of the metals followed the first-order rate constant in some of the samples, and the second-order in others within the first seven days. It was observed that the rate of corrosion follows this order: steel > iron > aluminium. The potential heavy and intolerable corrosion associated with the use of these seawater samples as injection waters is a potential risk that must be handled by adequate treatment.

Microstructural and Electrochemical study of Value-added Al-Si-Mg alloy reinforced with synthesis carbon nanotube and periwinkle shell nanoparticles for brake disc application

The corrosion performance of newly developed aluminum alloy composites using periwinkles shell nanoparticles (PWSnp) and carbon nanotube synthesis from rice husk (CNTs derived RH) replace the high weight and corrosion rate of the current gray cast iron (GCI) was investigate. the A356 alloy reinforced with 1.5wt%PWSnp and 0.5wt% CNTs derived RH was produced using the stir casting method. 5 wt% potassium sulfate (K2SO4(aq), 5 wt% sodium chloride (NaCl(aq), and 1 M sulfuric acid (H2SO4(aq) were used for the potentiostat/galvanostat corrosion performance of the friction materials. The corrosion resistance of the friction materials was in the order of NaCl(aq)˂ (H2SO4(aq))˂ K2SO4(aq). The composite has protection efficiency of 99.36, 99.44, and 98.97% over GCI in 5wt% NaCl, 5wt% K2SO4, and 1MH2SO4. This work has established that in terms of corrosion resistance the developed composite can be a replacement for the gray cast-iron brake disc.

Anticorrosion Study for Brass Alloys in Heat Exchangers during Acid Cleaning Using Novel Gemini Surfactants Based on Benzalkonium Tetrafluoroborate.

For a variety of applications, the brass alloy has been utilized to replace titanium tubes in heat exchangers. Copper alloys’ high corrosion rate during the acid cleaning procedure remains a significant concern. To inhibit the corrosion of brass alloys, we prepared two novel gemini surfactants (GSs), N1,N3-dibenzyl-N1,N1,N3,N3-tetramethylpropane-1,3-diaminium tetrafluoroborate (I H) and N1,N1,N3,N3-tetramethyl-N1,N3-bis (4-methyl benzyl) propane-1,3-diaminium tetrafluoroborate (I Me), and they were characterized using Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy. Their inhibition performance against corrosion of brass alloys in 1 M HCl was studied using electrochemical techniques including potentiodynamic polarization (PP), electrochemical impedance spectroscopy, and electrochemical frequency modulation. The inhibition effect of the synthesized compounds was high, and it increased as the inhibitor’s concentration was increased. The maximum level of inhibition efficiency was achieved at an inhibitor concentration of 100 ppm, reaching 96.42% according to PP measurements. From Langmuir data, the mechanisms of adsorption of the two GSs on the surface of copper was found to be physisorption and chemisorption adsorption. X-ray photoelectron spectroscopy and scanning electron microscopy show that the addition of the two compounds lowers the dissolution of brass ions in the corrosive solution and forms a protective layer on the surface of the brass.

Surface Modification of Pure Zinc by Acid Etching: Accelerating the Corrosion Rate and Enhancing Biocompatibility and Antibacterial Characteristics.

Zinc (Zn) has recently been identified as an auspicious biodegradable metal for medical implants and devices due to its tunable mechanical properties and good biocompatibility. However, the slow corrosion rate of Zn in a physiological environment does not meet the requirements for biodegradable implants, hindering its clinical translation. The present study aimed to accelerate the corrosion rate of pure Zn by utilizing acid etching to roughen the surface and increase the substrate surface area. The effects of acid etching on surface morphology, surface roughness, tensile properties, hardness, electrochemical corrosion and degradation behavior, cytocompatibility, direct cell attachment, and biofilm formation were investigated. Interestingly, acid-treated Zn showed an exceptionally high rate of corrosion (∼226-125 μm/year) compared to untreated Zn (∼62 μm/year), attributed to the increased surface roughness (Ra ∼ 1.12 μm) of acid-etched samples. Immersion tests in Hank's solution revealed that acid etching accelerated the degradation rate of Zn samples. In vitro, MC3T3-E1 cell lines in 50 and 25% conditioned media extracts of treated samples showed good cytocompatibility. Reduced bacterial adhesion, biofilm formation, and dispersion were observed for Staphylococci aureus biofilms cultured on acid-etched pure Zn substrates. These results suggest that the surface modification of biodegradable pure Zn metals by acid etching markedly increases the translation potential of zinc for various biomedical applications.

Effects of saltwater intrusion and sea level rise on aging and corrosion rates of iron pipes in water distribution and wastewater collection systems in coastal areas

Failure of water distribution and wastewater collection pipes can impact human health and environment due to potential contamination of water and soil in the surrounding areas, as well as service interruptions and road closures. This paper provides a quantitative assessment of projected shifts in failure rates of iron pipes due to saltwater intrusion and sea level rise in coastal areas. Probability of pipe failure depends on pipe characteristics, environmental parameters, and systems conditions. Analyses showed that saltwater intrusion and sea level rise can significantly affect the integrity of water and wastewater collection pipes due to potential changes in soil and groundwater characteristics that increase corrosion rates. Corrosion rate is intensified by increased conductivity of groundwater due to salinity. Coastal areas with subtropical climate have higher corrosion rates. The estimated lifetimes of ductile iron pipes are between 80 and 100 years. However, the actual service lifetimes can be significantly shorter. Pipes in subtropical areas corrode significantly faster than those in temperate climates. Presence of dissolved oxygen and chloride ion can significantly intensify the corrosion rates, shortening service times of iron pipes. Projections for pipe corrosion can help development of effective asset management strategies and for infrastructure maintenance planning in coastal areas that are vulnerable to sea level rise.

Effect of Adding Primary Epoxy on the Corrosion Rate of Low Carbon Steel in 3.56% NaCl Solution

The corrosion process occurs in almost all materials, especially metals, slowly but surely, which can cause a material to have a limited service life. Corrosion cannot be prevented but the rate can be reduced. One of the methods to inhibit the effective corrosion rate is by giving epoxy primer treatment. This study aims to examine the effect of adding epoxy primer on the corrosion rate of low carbon steel immersed in a 3.56% NaCl solution. This research was conducted using 27 specimens in 9 vessels, each vessel contained 3 specimens immersed in low carbon steel without treatment, oil paint and epoxy primer. Volume of 1 liter of 3.56% NaCl solution for 1 vessel. The results of this study indicate that the epoxy primer is able to inhibit the corrosion rate well. The reduction in weight of low carbon steel treated with oil paint is much greater than that of untreated low carbon steel using epoxy primer. The lowest corrosion rate was given by applying epoxy primer in 20 days of immersion with an average value of 0.0003761136666 mpy and the highest corrosion rate with paint treatment in 10 days of immersion with an average value of 0.004513367 mpy.

Experimental study on the mechanical properties of corroded RC columns repaired with large rupture strain FRP

This paper presents experimental results of the mechanical properties of corroded reinforced concrete (RC) columns repaired with large rupture strain (LRS) fiber-reinforced polymer (FRP). This work seeks to evaluate the effects of corrosion-induced damage, including concrete cracks and rebar buckling, on the confinement effectiveness of LRS-FRP. A total of sixteen RC columns were corroded to different extents by an electrochemical method and then repaired by wrapping them with FRP. A series of monotonic axial compression tests were conducted on these repaired specimens that were characterized by their corrosion conditions and FRP confinement rigidities. The test results show that LRS-FRP confinement effectively enhanced the mechanical properties of corroded RC columns. However, the existence of corrosion weakened the rebar cross-sections and further damaged the confined inner concrete, significantly influencing the compressive strength and ductility of the repaired RC columns. In addition, rebar buckling was more pronounced at higher corrosion rates, which affected the hoop strain distribution of the FRP and further reduced its confinement effectiveness. The existing ultimate condition models for confined concrete are also validated by the current test results, indicating that satisfied predictions can be made as the corrosion effects on confinement effectiveness are properly considered in these models.

Experimental and Statistical Approach to Detect the Corrosion Rate and Influencing Profiles for Enhancing Corrosion Rate of High-Voltage Insulator Materials.

The influence of temperature, pollutant, and pH on the local corrosion rate of insulators installed in industrial, marine, and rural installation sites is investigated based on experimental and statistical investigations. The tensile load test confirms that corroded insulator specimens collected from industrial sites aged more than 10years represent a minimum fracture load, 19,892 lbs. It was further observed that more than 91.24% and 64.62% corroded insulator specimens suffered from shell break and pin detachment, respectively. The microstructural and XRF analysis reveal that insulator specimens collected from industrial sites (age > 10years), represented the highest wt% of O (19.2) and lowest wt% of Zn (0.34) among industrial, marine, and rural installation sites. The 3D stationery mechanical simulation reveals that insulator specimens aged > 10years experienced maximum stress (600MPa) in the pin-cement interface. Using full two-level factorial designs, temperature, concentration of pollutants, and pH were found significant factors for corrosion rate. The immersion test results further confirm the above-mentioned factors significant for the dissolution behavior of galvanized coating of insulator pin. Following immersion test results, the industrial region shows the highest corrosion rate (5.58-12µm/year) among all installation sites.

Penggunaan Amilum sebagai Pelapis Anti Korosi pada Baja Karbon dalam Lingkungan Asam Klorida 0,5 M

The purpose of this paper was to determine the affect of amylum concentration and immersion time on the corrosion rate. Amylum is used as an anticorrosive coating on carbon steel in 0,5 M hydrochloric acid environment. Amylum concentration and immersion time affect the corrosion rate. The longer immersion time, the corrosion rate increases while the higher the concentration, the corrosion rate decreases. The highest corrosion rate was obtained at 3.58 mpy while the lowest corrosion rate was 1.24 mpy, Corrosion rates in metals can be prevented by the coating method

Corrosion of NiTiDiscs in Different Seawater Environments.

This paper gives an approach to the corrosion resistance analysis and changes in the chemical composition of anNiTi alloy in the shape of a disc, depending on different real seawater environments. The NiTi discs were analysed after 6 months of exposure in real seawater environments: the atmosphere, a tidal zone, and seawater. The corrosion tests showed that the highest corrosion rate for the discs is in seawater because this had the highest value of current density, and the initial disc had the most negative potential. Measuring the chemical composition of the discs using inductively coupled plasma and X-ray fluorescence before the experiment and semiquantitative analysis after the experiment showed the chemical composition after 6 months of exposure. Furthermore, the applied principal component analysis and cluster analysis revealed the influence of the different environments on the changes in the chemical composition of the discs. Cluster analysis detected small differences between the similar corrosive influences of the analysed types of environments during the period of exposure. The obtained results confirm that PCA can detect subtle quantitative differences among the corrosive influences of the types of marine environments, although the examined corrosive influences are quite similar. The applied chemometric methods (CA and PCA) are, therefore, sensitive enough to register the existence of slight differences among corrosive environmental influences on the analysed NiTi SMA.

Evaluation of the Corrosion Rate at the Bottom of the above – Ground Tank for Storage of Petroleum Products

A study of corrosion in steel fuel storage tanks, which failed after several years of operation highlighted intense pitting and microbiological corrosion. Significantly higher corrosion rates were found than would be expected with normal seawater corrosion. Therefore, the established methodology for predicting the remaining service life of tanks is also questionable. The aim of the study was to evaluate the actual corrosion rates at the bottom of the petroleum product tank. For this purpose, we adapted the established laboratory methods for evaluating the corrosion rate to perform field measurements. The observed corrosion rates in the tank are higher than the currently known values.

Corrosion Behavior of an Mg2Sn Alloy.

In the present work, the corrosion behavior of the Mg2Sn alloy (Mg66.7Sn33.3, concentration in at.%) has been studied. The alloy was prepared from high purity Sn and Mg lumps by induction melting in argon. The alloy was composed of intermetallic Mg2Sn with a small amount of Mg2Sn + (Sn) eutectic. The corrosion behavior was studied by hydrogen evolution, immersion, and potentiodynamic experiments. Three aqueous solutions of NaCl (3.5 wt.%), NaOH (0.1 wt.%) and HCl (0.1 wt.%) were chosen as corrosion media. The alloy was found to be cathodic with respect to metallic Mg and anodic with respect to Sn. The corrosion potentials of the Mg2Sn alloy were −1380, −1498 and −1361 mV vs. sat. Ag/AgCl in HCl, NaCl and NaOH solutions, respectively. The highest corrosion rate of the alloy, 92 mmpy, was found in aqueous HCl. The high corrosion rate was accompanied by massive hydrogen evolution on the alloy’s surface. The corrosion rate was found to decrease sharply with increasing pH of the electrolyte. In the NaOH electrolyte, a passivation of the alloy was observed. The corrosion of the alloy involved a simultaneous oxidation of Mg and Sn. The main corrosion products on the alloy surface were MgSn(OH)6 and Mg(OH)2. The corrosion mechanism is discussed and implications for practical applications of the alloy are provided.

Biodegradable Magnesium Biomaterials-Road to the Clinic.

In recent decades, we have witnessed radical changes in the use of permanent biomaterials. The intrinsic ability of magnesium (Mg) and its alloys to degrade without releasing toxic degradation products has led to a vast range of applications in the biomedical field, including cardiovascular stents, musculoskeletal, and orthopedic applications. With the use of biodegradable Mg biomaterials, patients would not suffer second surgery and surgical pain anymore. Be that as it may, the main drawbacks of these biomaterials are the high corrosion rate and unexpected degradation in physiological environments. Since biodegradable Mg-based implants are expected to show controllable degradation and match the requirements of specific applications, various techniques, such as designing a magnesium alloy and modifying the surface characteristics, are employed to tailor the degradation rate. In this paper, some fundamentals and particular aspects of magnesium degradation in physiological environments are summarized, and approaches to control the degradation behavior of Mg-based biomaterials are presented.

Mechanical properties and corrosion resistance of powder metallurgical Mg-Zn-Ca/Fe bulk metal glass composites for biomedical application

Magnesium (Mg) alloys can be regarded as the most promising biodegradable implant materials for orthopedic and stent applications due to their good biocompatibility and low Young's modulus which is near to that of natural bone. However, its applicability is hindered because it exhibits a high corrosion rate in the physiological environments. In this work, we fabricated Mg66Zn30Ca4/Fe bulk metallic glass composites via spark plasma sintering (SPS). We studied the influence of different contents of Fe on the properties of the composites. The results indicated that Fe was uniformly distributed on the surface of Mg66Zn30Ca4 metallic glass (MG) as a second phase, which led to an improvement in the corrosion resistance and mechanical strength. The standard potential of Mg66Zn30Ca4/Fe bulk metallic glass (BMG) composites increased as compared to Mg66Zn30Ca4, while their mechanical strength improved from 355 MPa to 616 MPa. Furthermore, cytotoxicity was investigated via the CCK-8 assay and calcein-AM staining, which revealed that the extraction mediums diluted 6 times (EM × 6) of the Mg66Zn30Ca4 and Mg66Zn30Ca4/Fe did not cause cell toxicity on day 3 and 5, while the EM × 6 of the Mg66Zn30Ca4 showed cytotoxicity on day 1, 3 and 5. Thus, Mg66Zn30Ca4/Fe BMG composites exhibit significant potential for fabricating implants with good mechanical strength and corrosion resistance.

Corrosion of SiC-coated graphite susceptor by NH3 and Cl2

This study aims to investigate the corrosion of a SiC-coated graphite susceptor using NH3 and Cl2 in an epitaxial growth environment. The corrosion performance of NH3 with graphite and SiC-coated graphite was investigated through microstructure characterization and mass loss rate changes in detail. Gaseous NH3 had a high corrosion rate on the graphite substrate, but hardly reacted with the SiC coating. Additionally, analyses of the tested samples revealed that Cl2 gas corroded the SiC coating at high temperatures and formed many corrosion holes and residual free carbon on the surface. As the Cl2 concentration increased, the corrosion depth gradually increased. Further experiments on commercial SiC-coated graphite susceptors showed that Cl2 preferentially corroded the grain boundaries of the SiC coating, and then the grains were corroded, resulting in a decrease in the coating strength until cracking and failure.

CaCO3-derived from eggshell waste for improving the corrosion resistance of zinc composite coating on mild steel for biodiesel storage tank

Sustainability of energy does not end in the generation of biofuels, but as well encompasses proper mitigation of the metallic equipment used in the plant from corrosion degradation. Corrosion of metallic equipment in biodiesel plants limits the storage and distribution of biodiesel to the end-users. Carbon steel of Mild steel type/grade is one of the major metallic materials used in the construction of biodiesel storage tanks. The major setback of using mild steel for biodiesel storage is the high corrosion rate. This research aims to develop a novel coating of mild steel using CaCO3 derived from eggshell waste (ESP). The Codeposition method was used to develop Zn-10%CaCO3-ESP (single and double layer). The corrosion of the samples was tested in a Jatropha curcas biodiesel (JBD) environment. Microstructure, hardness values, viscosity, and density of the oil were determined. A corrosion protection efficiency of 68.87% was obtained using the Zn-10%CaCO3-ESP double layer. High corrosion damage as a result of localized pitting corrosion mechanism was observed for the mild steel without coating. This novel coating can be used in the industrial fabrication of storage tanks for biodiesel since the CaCO3-ESP is prepared by a simple method.

Microstructural, morphological characterization and corrosion behavior of sand cast AlSi10Cu(Fe) alloy in chloride solution

In order to examine the relationship between the microstructure and the corrosion behavior in chloride solution, the microstructure of AlSi10Cu (Fe) sand cast aluminum alloy has been investigated by using different techniques including scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction analysis and electrochemical measurements. The microscopic analysis and X-ray diffraction analysis show several phases in addition to matrix phase, including pores and phases at nano- and microscales. The average rate of micropores and nanopores is 4% and 5%, respectively. The nanoparticle size varies between 20 and 150 nm. Plates and corals-like silicon eutectic, rich-Cu phase and Chinese script phase (Al15(Mn,Fe)3Si2) have been observed. Energy-dispersive spectroscopy analyses show the presence of a new phase (Cu61.22 Zn25.39Ni11.85 Al1.54), and the pitting corrosion has been demonstrated to be initiated at the nanopores. The electrochemical measurements exhibited the effect of several elements and porosities on the corrosion kinetics that is controlled by charge transfer and diffusion phenomenon. Wide passive windows, followed by the breakdown of passive film and excessive dissolution, have been observed in 0.3 and 3 wt% NaCl solutions. The electrochemical measurements show a high corrosion rate which does not recommend the use of this alloy in seawater.