Showing papers in "Anti-corrosion Methods and Materials in 2015"
TL;DR: In this article, the use of aqueous extract of date palm (Phoenix dactylifera) leaf as a green inhibitor for corrosion of carbon steel in 1M hydrochloric acid (HCl) solution was investigated.
Abstract: – The purpose of the paper was to investigate the use of aqueous extract of date palm (Phoenix dactylifera) leaf as a green inhibitor for corrosion of carbon steel in 1M hydrochloric acid (HCl) solution. , – Extracts from the date palm were used as the main component of an environmentally friendly corrosion inhibitor for use in HCl pickling processes. Inhibition behavior on carbon steel in HCl was investigated using weight loss measurements, linear and potentiodynamic polarization curves, electrochemical impedance spectroscopy and scanning electron microscopy. , – The results show that the extract exhibited good inhibition performance in 1M HCl. The inhibition efficiency increased with increase in the concentration of the inhibitor but decreased with increase in temperature. Inhibition efficiency also was found to increase as immersion time increased. The inhibitive action was due to adsorption of the date palm leaf components on the steel, which was consistent with the Langmuir isotherm. , – Date palm leaf extract (DPLE) is an effective inhibitor at room temperature and can be used to protect plain carbon steel from corrosion in HCl solution. , – This study provides new information on the inhibiting characteristics of DPLE under specified conditions. The environmentally friendly inhibitor could find possible applications in metal surface anodizing and acid pickling processes.
29 citations
TL;DR: In this article, the effect of exposure of underground electrical cables to chemically contaminated water was investigated and it was concluded that contamination in the water had degraded the cable, resulting in the development of a network of branched cracks within the cable insulation through which water could permeate, leading to eventual failure of the cable.
Abstract: Purpose
– This paper aims to determine the effect of exposure of underground electrical cables to chemically contaminated water.
Design/methodology/approach
– Visual inspection and photography were carried out to record the appearance of electrical cables. Failed and un-failed cable samples were collected and analyzed using light microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Sand and water samples were chemically tested for contaminants.
Findings
– Underground low-voltage 0.6/1-kV cross-linked polyethene insulated cables belonging to a chemical production plant suffered failure after four years of service. Excavation of the cable trench revealed that the cables were buried in sand polluted with chemically contaminated water. The cables were discolored and covered with corrosion deposits. Experimental results indicated that the cable insulation was heavily degraded and the outer jacket of polyvinyl chloride exhibited cracks that had penetrated through its thickness. Water and sand surrounding the cable were found to have high concentrations of ammonia. Mechanical testing of the cables indicated high values of stiffness that could contribute to the formation of cracks at the surface.
Practical implications
– It was concluded that contamination in the water had degraded the cable, resulting in the development of a network of branched cracks within the cable insulation through which water could permeate, leading to eventual failure of the cable. Accelerated degradation took place due to exposure to the contaminated environment, which promoted aging and brittleness. Continued exposure of electric cables to contamination would lead to power failures and plant shutdowns.
Originality/value
– This paper provides an account of a failure investigation of low-voltage electrical cable buried underground. It discusses the role of contaminated environment in the eventual failure of electrical cable due to corrosion. This information will be useful for plant engineers and project managers working in any industry that makes use of chemicals.
27 citations
TL;DR: In this paper, the effects of parameters influencing the inhibition process (concentration and temperature) were evaluated, and the sorption isotherms and thermodynamic parameters were derived.
Abstract: Purpose – The purpose of this investigation was to study the inhibitive action and adsorption potential of chitosan extracted from Archachatina marginata snail shells on the corrosion of plain carbon (mild) steel in acid media. Design/methodology/approach – Weight loss and thermometric methods were used during this investigation. Characterization of the obtained chitosan was accomplished with Fourier transform infrared spectroscopy analysis. The effects of parameters influencing the inhibition process (concentration and temperature) were evaluated, and the sorption isotherms and thermodynamic parameters were derived. Findings – The results obtained showed that chitosan has good inhibition potential with an efficiency of 93.2 per cent. The inhibition efficiency decreased with an increase in temperature but increased with increasing concentration of chitosan. Test results best fitted the Langmuir Isotherm with a correlation coefficient (R2) of 0.999. The thermodynamic parameters studied reveal that the adso...
17 citations
TL;DR: In this article, a selfaggregated, eco-friendly, water-soluble hyperbranched polyamide-ester (Hb-PAE) was synthesized through bulk polycondensation reaction between maleic anhydride and di-isopropanol amine.
Abstract: Purpose – The purpose of this paper was to protect carbon steel from corrosion with self–aggregated, eco-friendly, water-soluble hyperbranched polyamide-ester (Hb-PAE). Design/methodology/approach – Hb-PAE was synthesized through bulk polycondensation reaction between maleic anhydride and di-isopropanol amine. Complete structural analysis for the obtained polymer was performed using Fourier Transfer Infra-Red Spectroscopy, 1H NMR, Thermal gravimetric analysis (TGA) and differential scanning calorimetry, and the molar mass was measured using gel permeation chromatography/refractive index. For this study, the surface activity of Hb-PAE with hydroxyl end groups was investigated. Surface tension of 1.0 × 10−6 to 0.1M of both Hb-PAE/H2O and Hb-PAE/1N HCl systems was measured, and the critical aggregation concentration (CAC) in both systems was determined. Hb-PAE was examined as a corrosion inhibitor for plain carbon steel in both neutral (distilled water) and acidic (1N HCl) media. The corrosion of the steel w...
14 citations
TL;DR: In this paper, the effect of thermal treatment on the corrosion protection of steel by using poly(3-hexylthiophene) (P3HT) and P3HT/PS(polystyrene) or polymethyl methacrylate (PMMA) blends coatings in sulfuric acid solution was studied.
Abstract: Purpose – The purpose of this paper is to study the effect of thermal treatment on the corrosion protection of steel by using poly(3-hexylthiophene) (P3HT) and P3HT/PS(polystyrene) or P3HT/PMMA(polymethyl methacrylate) blends coatings in sulfuric acid solution. Design/methodology/approach – The polymer coatings were thermally treated at two different temperatures (100 and 200°C, respectively) and were compared with the polymer coatings dried at room temperature in their application as protective coatings against corrosion of A36 steel. The corrosion resistance of polymer coatings-covered steel substrates was evaluated by using potentiodynamic polarization curves and linear polarization resistance. Findings – At 25 and 100°C, polymer coatings showed a better protection of the A36 steel, and the corrosion rate diminished in three orders of magnitude with regard to the bare steel. Morphological study showed that the increased temperature benefited the integration of the two polymeric phases; however; the tem...
12 citations
TL;DR: In this article, a grey relational analysis method was used to evaluate the importance of various environmental factors in determining quickly the important factors affecting the atmospheric corrosion of Q235 carbon steel in one year, and the results obtained by this method showed that the ranking order of factors that affect the corrosion of carbon steel from slightly to severely was as follows: relative humidity > dew days > SO3 > pH value of rain > rain precipitation > temperature > rainy days > Cl− > H2S > NO2.
Abstract: Purpose – The purpose of this study was to evaluate the grey relational analysis method as a way of determining quickly the important factors affecting the atmospheric corrosion of Q235 carbon steel in one year. Design/methodology/approach – Atmospheric corrosion exposure tests on Q235 steel were carried out at seven typical test sites in China. The test period lasted one year. The corrosion rate of the Q235 test panels was determined using the weight-loss method and environmental factors were monitored and recorded by standard methods. The importance of the various environmental factors was evaluated using the grey relational analysis method. Findings – The results obtained by the grey relational analysis method showed that the ranking order of factors affecting the corrosion of Q235 carbon steel from “slightly” to “severely” was as follows: relative humidity > dew days > SO3 > pH value of rain > rain precipitation > temperature > rainy days > Cl− > H2S > NO2. Furthermore, the initial atmospheric corrosi...
11 citations
TL;DR: In this article, the authors used the extract of barley as an environmentally friendly inhibitor for the acid corrosion of steel due to its wide availability as a popular major crop and its richness with different chemical constituents reported in literature.
Abstract: Purpose – The purpose of this paper was to test the extract of barley as an environmentally friendly inhibitor for the acid corrosion of steel due to its wide availability as a popular major crop and its richness with different chemical constituents reported in literature (40) like alanine, glycine, serine, aspartic acid, leucine, valine, tyrosine and isoleucine with various number of functional groups that are able to chelate metal cations and to discuss the effect of temperature on its inhibition efficiency. Design/methodology/approach – Electrochemical impedance spectroscopy (EIS) and polarization measurements were carried out using frequency response analyzer Gill AC instrument. The frequency range for EIS measurements was 0.1 ≤ f ≤ 1 × 103 with an applied potential signal amplitude of 10 mV around the rest potential. Polarization measurements were carried out at a scan rate of 30 mV/min, utilizing a three-electrode cell. A platinum sheet and saturated calomel electrode were used as counter and refere...
11 citations
TL;DR: In this paper, the semi-conductive behavior of the passive layer formed in concrete environment without and with presence of chloride ions under different loading conditions was investigated using Mott-Schottky technique.
Abstract: Purpose – This paper aims to clarify the semi-conductive behavior of the passive layer formed in concrete environment without and with presence of chloride ions under different loading conditions. Passivation and depassivation of steel play an essential role in the subsequent stages of the corrosion process. Due to the nature of passive films on metals, they show electrochemical properties of a semi-conductor. Design/methodology/approach – A C-ring model was proposed in this experiment to induce stress on the specimens. Specimens under different levels of compressive and tensile loadings were exposed to chloride-free and chloride-contaminated solutions and their semi-conductive behavior was investigated using Mott–Schottky technique. Findings – Irrespective of the type and magnitude of the applied load, the passive film on rebars in simulated concrete pore solution is a highly disordered n-type semi-conductor. In all specimens, the presence of chloride ions decreases the slope of the Mott-Schottky plots, ...
11 citations
TL;DR: In this paper, a double-nozzle gun was used to spray two different solutions containing the precursors onto the surface of a composite NiBP-graphite film and their corrosion and tribological properties were investigated.
Abstract: Purpose – This paper aims to coat ternary composite NiBP-graphite films by Dynamic Chemical Plating “DCP” technique with a growth rate of at least 5 μm/h, which makes this technique a worthy candidate for production of composite films. Electroless nickel plating method can be used to deposit nickel–phosphorous and nickel–boron coatings on metals or plastic surface. However, restrictions such as toxicity, short lifetime of the plating-bath and limited plating rate have limited applications of conventional electroless processes. Design/methodology/approach – DCP is an alternative for producing metallic deposits on non-conductive materials and can be considered as a modified electroless coating process. Using a double-nozzle gun, two different solutions containing the precursors are sprayed simultaneously and separately onto the surface. With this technique, NiBP-graphite films are fabricated and their corrosion and tribological properties are investigated. Findings – With a film thickness of 2 μm, tribologi...
11 citations
TL;DR: In this article, the corrosion resistance of AA2024 alloy using surfactant-modified halloysite nanocapsules capable of holding benzotriazole (BTA) as the corrosion inhibitor and discharging it into the solution was investigated.
Abstract: Purpose – The purpose of this paper was to study the corrosion resistance of AA2024 alloy using surfactant-modified halloysite nanocapsules capable of holding benzotriazole (BTA) as the corrosion inhibitor and discharging it into the solution. Design/methodology/approach – The effect of surfactant shells was studied by surfactant-modified halloysite nanotubes fabricated through assembly of two types of cationic surfactants. The zeta potential and size distribution measurements were performed using a Zetasizer Nano. The concentration of BTA during release into the solution was detected by using a UV–vis spectrophotometer. The anti-corrosion activity of nanocapsules as free agents with respect to the AA2024 alloy was investigated using the potentiodynamic scan (PDS) method. An epoxy resin doped with nanocapsules was used as an anti-corrosion coating deposited on the AA2024 alloy. The corrosion protection performance of coatings was studied by using the electrochemical impedance spectroscopy (EIS) method. Fi...
10 citations
TL;DR: In this article, the authors evaluated the inhibition efficiency of thiadiazole derivatives, such as 2,5-dimercapto-1,3,4-thiamidiazole (DMTD), 5-methly-2-mercapto, 1, 3, 4-thimidiazoles (MMTD), and 2, 5-dithiododecyl-1.3, 4thiamide (DDTD), in 50 mg/L hydrogen sulfide for silver strip.
Abstract: Purpose – This paper aims to evaluate the inhibition efficiency of thiadiazole derivatives, such as 2,5-dimercapto-1,3,4-thiadiazole (DMTD), 5-methly-2-mercapto-1,3,4-thiadiazole (MMTD) and 2,5-dithiododecyl-1,3,4-thiadiazole (DDTD), in 50 mg/L hydrogen sulfide for silver strip. Design/methodology/approach – Evaluation was carried out by corrosion-inhibiting test, electrochemical measurement and surface analysis techniques. 3D surface profiler, atom force microscopy, scanning electron microscopy and energy-dispersive X-ray analysis were applied and finally confirmed the existence of the adsorbed film. Findings – The electrochemical measurement showed that the inhibition efficiency increases with increasing inhibitor concentration in 50 mg/L hydrogen sulfide solution, while the corrosion rate and the corrosion current decrease. Weight-gained measurements also indicated that inhibitor decreases the corrosion rate in the studied solution. The adsorption of DMTD and MMTD on the silver surface obeys Temkin’s a...
TL;DR: In this paper, an anti-corrosion system that combined conductive coatings with cathodic protection for a 500-kV substation ground grid, and provide a basis for the anticorrosions construction of the installation, is presented.
Abstract: Purpose – The purpose of the paper was to design an anti-corrosion system that combined conductive coatings with cathodic protection for a 500-kV substation ground grid, and provide a basis for the anti-corrosion construction of the installation. Design/methodology/approach – The study took the Shaoguan 500-kV substation grounding grid as the research object. The anti-corrosion performance of KV conductive coatings on grounding metal was researched. In parallel, the alkalinity of substation soil was evaluated according to the German DIN50929 Standard, and the combined protection system comprising conductive coatings and impressed current cathodic protection was designed. Findings – KV conductive coatings, that have resistance to acids, alkalis and salts, can effectively slow down the corrosion rate of the grounding grid. The investigation also provided the outline design, installation, construction requirements and monitoring methods for the 500-kV substation grounding grid. Originality/value – This repor...
TL;DR: In this article, the influence of tensile stress on the electrochemical behavior of X80 steel in a simulated acid soil solution was investigated using electrochemical impedance spectroscopy, potentiodynamic scan measurements and surface analysis techniques.
Abstract: Purpose – The aim of this paper was to clarify the influence of tensile stress on the electrochemical behavior of X80 steel in a simulated acid soil solution and attempt to understand mechanistic aspects of the corrosion behaviors of X80 under these conditions. Design/methodology/approach – The electrochemical behavior of X80 steel at various tensile stresses was investigated in a simulated acid soil solution using electrochemical impedance spectroscopy, potentiodynamic scan measurements and surface analysis techniques. Findings – The results show that as tensile stress was increased, the open-circuit potential decreased, the reaction activity increase, the reaction resistance (Rct)value became smaller by degrees, the corrosion product film resistance (Rf) first decreased and then increased and polarization current densities changed conversely. The corrosion product film was compact and continuous under the low stress, whereas it was relatively loose under high-stress conditions. Tensile stress promotes t...
TL;DR: In this article, the influence of temperature and lignin concentration on the inhibition of carbon steel corrosion in 1 M HCl was investigated, and it was found that the corrosion inhibition efficiency (IE) decreased when the temperature was increased from 60 to 70°C.
Abstract: Purpose – This paper aims to investigate the influence of temperature and lignin concentration on the inhibition of carbon steel corrosion in 1 M HCl. Design/methodology/approach – Weight loss corrosion tests were performed at different temperatures in the range of 30-70°C (303-343 K). Findings – It was found that the corrosion inhibition efficiency (IE) of lignin on the carbon steel decreased when the temperature was increased from 60 to 70°C. However, at lower temperatures ranging from 30 to 50°C, the IE improved, due to occurrence of lignin adsorption on the surface of metal specimens. The IE was higher with increasing lignin concentration, thus reducing the weight loss of the carbon steel. The adsorption phenomenon involved exothermic processes because the value of enthalpy of adsorption (ΔH°ads) < 0 and Gibbs free energy of adsorption (ΔG°ads) were less negative with increase in temperature. The entropy of adsorption (ΔS°ads) had negative values, representing the decrease in disorder of adsorption. T...
TL;DR: In this article, a laboratory accelerated periodic immersion wet/dry cyclic corrosion test is presented to evaluate the atmospheric corrosion resistance of weathering steels in a very short period, i.e. 1 hour.
Abstract: Purpose – The purpose of this paper is to present a laboratory accelerated periodic immersion wet/dry cyclic corrosion test, reflecting the alternate wet/dry process during the atmospheric exposure of metallic materials, which can be applied to evaluate the atmospheric corrosion resistance (ACR) of weathering steels in a very short period. Design/methodology/approach – This test method uses 0.01 M sodium bisulfite aqueous solution with pH 4.4 as the immersion medium, simulating the notable characteristics of sulfur dioxide pollutant in industrially polluted atmospheres. During the test process, the tested specimens are immersed into the solution for 12 minutes, immediately followed by the subsequent drying process for 48 minutes, and such alternate process consists of a cyclic period, i.e. 1 hour. As a result of this procedure, a relative corrosion rate is defined to determine the ACR. To determine a preferred test period, different test periods including 72 and 200 hours were compared. Findings – Compare...
TL;DR: In this article, the micro-cracked morphology of the rare earth passivation film was investigated using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and its compositions, micro-morphology, corrosion resistance and the chemical valence state of the film elements were investigated.
Abstract: Purpose – The purpose of this paper was to prepare the cerium-based conversion coating on AZ91D magnesium alloy, and its compositions, micro-morphology, corrosion resistance and the chemical valence state of the film elements were investigated. Design/methodology/approach – The methodology comprised preparation of coatings at different temperatures, which then were characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, an electrochemistry workstation and by means of X-ray photoelectron spectroscopy. Findings – The conversion coating had a micro-cracked morphology. The conversion coatings were composed of MgO (or Mg-OH), CeO2 and Ce2O3. The best corrosion resistance of the cerium passivation film appeared when the treatment temperature was about 35°C. Originality/value – The corrosion current densities of conversion coatings were lower by one to two orders of magnitude than the corrosion current density of the blank sample. The rare earth passivation coating pre...
TL;DR: In this article, a correlation study on general and accelerated corrosion of the welded structure of aluminum alloy 2219 in N2O4 was presented, and the experimental results indicated that both the accelerated and mild corrosion processes of the TIG-welded structure followed the linear equation ΔW = A + Bt.
Abstract: Purpose – This paper aims to present a correlation study on general and accelerated corrosion of the welded structure of aluminum alloy 2219 in N2O4. Design/methodology/approach – Corrosion experiments of the Tungsten Inert Gas (TIG)-welded aluminum alloy structure were conducted under both mild and accelerated corrosion conditions by changing the water content in N2O4. Findings – The experimental results indicated that both general and accelerated corrosion processes of the TIG-welded structure of aluminum alloy 2219 in N2O4 followed the linear equation ΔW = A + Bt, and the corrosion products were unchanged regardless of the water content in the N2O4 solution. Originality/value – The weight loss comparison method is used to identify the structure of the conventional aluminum welding and aluminum welding structure corrosion dinitrogen tetroxide in nitric acid accelerated corrosion relationship.
TL;DR: In this article, the anticorrosion pigments were prepared by high-temperature, solid-state synthesis from the respective oxides, carbonates and calcium metasilicate.
Abstract: Purpose – This paper aims to synthesize anticorrosion pigments containing tungsten for paints intended for corrosion protection of metals. Design/methodology/approach – The anticorrosion pigments were prepared by high-temperature, solid-state synthesis from the respective oxides, carbonates and calcium metasilicate. Stoichiometric tungstates and core-shell tungstates with a nonisometric particle shape containing Ca, Sr, Zn, Mg and Fe were synthesized. The pigments were examined by X-ray diffraction analysis and by scanning electron microscopy. Paints based on an epoxy resin and containing the substances at a pigment volume concentration (PVC) = 10 volume per cent were prepared. The paints were subjected to physico-mechanical tests and to tests in corrosion atmospheres. The corrosion test results were compared to those of the paint with a commercial pigment, which is used in many industrial applications. Findings – The tungstate structure of each pigment was elucidated. The core-shell tungstates exhibit a ...
TL;DR: In this paper, the authors report on the corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels, using immersion test and electrochemical polarization tests to evaluate the uniform and localized corrosion.
Abstract: Purpose – This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels Design/methodology/approach – For this purpose, immersion test and electrochemical polarization tests were conducted in mill and synthetic effluent to evaluate the uniform and localized corrosion Findings – Corrosivity of mill effluent has been compared with synthetic and primary-stage effluent of the same mill It is observed that anions present in them, viz SO4−, PO34−, NO2− and NO3−, impart inhibition, whereas Cl− and chlorophenols enhance the corrosivity of the effluent The overall effect of various components was reduction in corrosivity of secondary mill effluent Originality/value – These observations can be useful for material selection and helpful in corrosion mitigation in paper mill effluent treatment plants
TL;DR: In this paper, the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests was investigated using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s−1.
Abstract: Purpose – The aim of this paper was to investigate the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests. Design/methodology/approach – The specimens were prepared using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s−1, and the corresponding flow curves and deformation microstructure obtained were further analyzed. To evaluate the effect of strain rate on corrosion behavior, potentiodynamic polarization tests and double-loop electrochemical potentiodynamic reactivation (DL-EPR) were used to characterize the electrochemical performance. Findings – Compared with strain rate of 0.5 s−1, the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s−1 was attributed to more austenite (γ) and ferrite (δ) grain boundaries or δ/γ phase interface formation due to the better effect of γ dynamic rec...
TL;DR: In this article, the authors investigated the mechanical performance of multi-layer films using the DC magnetron sputtering method and found that interface effects on the mechanical properties and corrosion resistance of the films were analyzed.
Abstract: Purpose – The aim of the present paper is to investigate the mechanical performance of multi-layer films With the wide application of optic and electronic thin-films, membrane materials and membrane technology have become one of the most active fields of research in contemporary materials science (Dumont et al, 1997) Multi-layer films have evolved as candidates for these applications because of their unique properties TiN and Ti/TiN multi-layer films were fabricated using the DC magnetron sputtering method A nano-indentation tester and electronic film distribution tester were utilized to evaluate the mechanical properties and residual stress of the films The existence of interface effects on the mechanical properties and corrosion resistance of the films were analyzed Design/methodology/approach – In this study, the Ti/TiN multi-layer films were fabricated using the DC magnetron sputtering method The films were deposited on polished 45# steels Ti was used as the sputtering target Ar and N2 were
TL;DR: In this article, the authors investigated the inhibition performance of the oxide film (OF) covering a sample of L360 steel and its surface morphology was observed using scanning electron microscopy.
Abstract: Purpose – The aim of the present paper was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO2/H2S environments. The pipeline steel surface usually has been pre-treated before using in the oil/gas field, such as by passivation, blackening, and phosphiding. The effectiveness of inhibition can vary because there are many differences between the metal matrix and the treated film. Design/methodology/approach – Imidazoline (IM) was synthesized by using oleic acid and diethylenetriamine, and its composition was verified using Fourier transform infrared spectroscopy. The oxide film (OF) covering a sample of L360 steel was characterized using X-ray diffraction, and its surface morphology was observed using scanning electron microscope. Electrochemical impedance spectroscopy measurements were conducted to study the inhibition performance of IM- and/or OF-covered L360 steel in the CO2/H2S environments. Findings – The results show that IM and OF can prevent corrosion on L360 steel in C...
TL;DR: In this paper, a transparent coating based on organic silicone resins prepared by the hydrolysis and condensation of methyltriethoxysilane and tetraethoxisilane was investigated.
Abstract: Purpose – The purpose of this investigation was to study a transparent coating based on organic silicone resins prepared by the hydrolysis and condensation of methyltriethoxysilane and tetraethoxysilane. Design/methodology/approach – The coating film was characterized by IR, UV, thermal gravity analysis, scanning electron microscope and an automatic contact angle meter. Some properties of the coating film, such as adhesion, impact resistance and wear-resistance also were evaluated. Findings – These uniform, clear and smooth coating films possessed the high transparent and light transmittance, high density, high hydrophobicity, good adhesion, hardness and anti-corrosion. Originality/value – The coating may be considered as a protective film for the surfaces of the metals and plastics.
TL;DR: In this paper, a newly developed type of organic inhibitor, V-active VCIs, was used to eliminate or reduce the oxidizing action of water, thereby extending the allowable time before painting after hydrojetting, and that the new corrosion inhibitor technology does not interfere with the final quality of paint adhesion.
Abstract: Purpose – This work describes test results that were obtained using a newly-developed type of organic inhibitor: V-active VCIs. The findings demonstrate that is possible to eliminate or reduce the oxidizing action of water, thereby extending the allowable time before painting after hydrojetting, and that the new corrosion inhibitor technology does not interfere with the final quality of paint adhesion. Design/methodology/approach – Metallic specimens were treated/washed by hydrojet (35000 Psi). It was employed as a 2 per cent V-active VCI SPH 1,712 water solution by dilution of the inhibitor in industrial water. Metal sample plates were examined after blasting and after subsequent drying, and were submitted to the paint adhesion tests, to evaluate the duration of temporary protection, oxidation prevention and influence on the adherence of paint (pull off). Findings – Using the V-active VCI proposed technology, it was possible to minimize or eliminate the oxidizing action of the water when the metal is exp...
TL;DR: In this paper, the authors evaluated the anti-corrosion performance of superheater T91 tube material in a condensate environment with high temperature exposure tests and found that the corrosion rates of T91 material would increase with temperature.
Abstract: Purpose – The purpose of this paper was to evaluate corrosion resistance of superheater T91 material based on high temperature corrosion experiments with a condensate environment. Design/methodology/approach – The contributions of water temperature, chloride concentration and corrosion time were considered and analyzed for modeling corrosion kinetics. The corrosion tendency also was predicted, and the results were compared with higher temperature exposures of T91 tube material installed in a biomass power plant. Findings – High temperature exposure tests showed that the corrosion rates of T91 material would increase with temperature; there was a very evident corrosion acceleration point in 110°C. It was concluded that dimensional homogeneity analysis can serve as a viable evaluation method for T91 superheater material. Originality/value – Dimensional homogeneity analysis was used as evaluation method for anti-corrosion performance of T91 superheater material.
TL;DR: In this paper, the effect of SBF artificial body fluid on microstructure and morphology characteristics of AZ91D alloy was investigated using OM, SEM and XRD, and the results showed that the corrosion weight loss rate initially increased, then clearly decreased, and finally remained steady.
Abstract: Purpose – The effect of SBF artificial body fluid on microstructure and morphology characteristics of AZ91D alloy was investigated using OM, SEM and XRD. The effect of corrosion on mechanical properties also was researched. Design/methodology/approach – The results show that the corrosion weight loss rate initially increased, then clearly decreased, and finally remained steady. Pits began to appear when the sample was placed in a corrosive environment for five days and pitting gradually increased with longer exposure time. Findings – The pits, which made the grain boundaries indistinct, first appeared near the grain boundary area and then gradually increased in area. Originality/value – The main mode of corrosion is pitting and the primary corrosion product, MgOH2, could be observed after five days of corrosion.
TL;DR: In this article, the authors explored the differences in the corrosion behavior of carbon steel in simulated reverse osmosis (RO) product water, and in seawater, and found that the average corrosion potential, micro-cathode potential and micro-anode potential of the WBE decreased with time in simulated RO product water.
Abstract: Purpose – The purpose of this study was to explore the differences in the corrosion behavior of carbon steel in simulated reverse osmosis (RO) product water, and in seawater. Design/methodology/approach – The wire beam electrodes (WBE) and coupons made from Type Q235 carbon steel and were immersed in simulated reverse osmosis product water, and in seawater, for fifteen days. The corrosion potential distribution on the WBE at different times was measured. The corrosion rates of the carbon steel in different solutions were obtained using weight loss determinations. The different corrosion behavior of carbon steel in the two kinds of solution was analyzed. Findings – The results showed that the average corrosion potential, micro-cathode potential and micro-anode potential of the WBE decreased with time in simulated RO product water. During this period, the maximum potential difference between micro-cathodes and micro-anodes on the WBE surface also decreased with time. The potential difference was more than 2...
TL;DR: In this paper, an engine component made from 1Cr18Ni9Ti alloy to be used underwater was the subject of the present research investigation, where a stereomicroscope, a metallurgical microscope, a microhardness tester and an electron energy dispersion spectroscope were used to observe cross-sections of the alloy's microstructure at different locations, as well as its overall corrosion behavior.
Abstract: Purpose – An engine component made from 1Cr18Ni9Ti alloy to be used underwater was the subject of the present research investigation. Design/methodology/approach – A stereomicroscope, a metallurgical microscope, a microhardness tester and an electron energy dispersion spectroscope were used to observe cross-sections of the alloy’s microstructure at different locations, as well as its overall corrosion behavior. Findings – The corrosion of the 1Cr18Ni9Ti alloy, attributed to welding, cold processing and plastic deformation processes, was investigated together with an analysis of the chemical composition of the corrosion products and microsclerometry of the cross-sections. It was revealed that defects such as shrinkage cavities and porosity, often were observed to occur in the welding fusion zone. During cold processing treatments, work hardening was induced in the surface layer. Corrosion products consisted of oxides, chlorides and sulfides, with oxides as the dominant component. The high chromium content ...
TL;DR: In this paper, the authors evaluated the performance of corrosion inhibitors in acid medium through the determination of Fe2+ ions present based on reaction kinetics of steel with the acid, and the results showed that the addition of commercial corrosion inhibitor base of ethoxylated amines of high molecular weight in an acid medium showed excellent performance at a temperature ranging fro...
Abstract: Purpose – The purpose of this paper is to evaluate the corrosion inhibitor performance in acid medium through the determination of Fe2+ ions present based on reaction kinetics of steel with the acid. The use of corrosion inhibitors has been an excellent technique for protecting carbon steel pipes acidizing operations in oil wells. The inhibitor forms a chemical barrier on the metal surface that prevents or reduces attack by the acidic media. Design/methodology/approach – The experimental study provides a methodology to evaluate the performance of corrosion inhibitors in an acid medium, preferentially of concentrated hydrochloric acid. The process consists essentially of total immersion coupons of carbon steel, with continuous stirring, controlled temperature and quantitative determinations of iron ions from the dissolution of steel. The additions of commercial corrosion inhibitor base of ethoxylated amines of high molecular weight in an acid medium showed excellent performance at a temperature ranging fro...
TL;DR: In this article, the authors study the potential distribution of the buried pipeline cathodic protection potential distribution and the control equations are solved using the boundary element method using BEASY software, respectively.
Abstract: Purpose – The purpose of this investigation was to study these problems and design regional cathodic protection, using numerical simulation. Regional cathodic protection technology is immature at home and abroad. This is reflected in the fact that in gas stations, there are many underground pipelines, which can lead to serious interference and shielding phenomena, and there are many grounding networks that can cause substantial loss of the cathodic protection current. Design/methodology/approach – Based on the above, in this article, first of all, the mathematical model of the buried pipeline cathodic protection potential distribution was established and the control equations solved using the boundary element method. Second, the cathodic shielding effect in pipeline concentration areas, the effect of instrument equipment grounding systems on cathodic protection and the influence of DC stray current on the interference of pipeline corrosion were studied separately using BEASY software. Finally, the BEASY s...