Addition Of Corrosion Inhibitor Research Articles

Al-4.06Mg-0.74Mn 합금의 해수 내 캐비테이션 환경에 따른 정전위 특성 평가

The hull of a fast sailing aluminium ship are generally prone to erosion owing to the impact of seawater. At this time, synergistic effects of the erosion and the corrosion by aggressive ions such as chlorides tend to aggravate the damage. There have been various attempts, including selection of erosion-resistant materials, cathodic protection and addition of corrosion inhibitors, to overcome damage by erosion or corrosion under marine environments. These approaches, however, have limits on identifying the damage mechanism clearly, because they depend on analogical interpretation by correlating two damage behaviors after the individual studies are assessed. In this research, it was devised a hybrid testing apparatus that integrates electrochemical corrosion test and cavitation test, and thus the erosion-corrosion behavior by cavitation was investigated more reliably. As a result, the slightest damage was observed at the potentials between -1.6 V and -1.5 V. This is considered to be due to a reflection or counterbalancing effect caused by collision of the cavitation cavities and the hydrogen gas formed by activation polarization.

Study on the corrosion behavior of Q235A carbon steel in RO product water of seawater

PurposeSome power plants in China that adopt reverse osmosis (RO) product water as their fresh water source face serious metal corrosion of their water distribution system. The corrosion process of carbon steel in RO product water is still not clear and there is no suitable anti‐corrosion method for the power plant to employ. The purpose of this paper is to study the corrosion behavior of carbon steel in RO product water, determine the factors leading to the high corrosion rate of carbon steel, and then suggest appropriate anti‐corrosion measures.Design/methodology/approachBy measuring polarization curves and AC impedance values of the corrosion system and analyzing corrosion products using scanning electron microscopy (SEM), infrared spectroscopy (IR) and X‐ray diffraction (XRD), the corrosion behavior of Q235A carbon steel in the RO product water derived from seawater was studied.FindingsThe experimental results showed that the corrosion process of carbon steel in RO product water is controlled by the diffusion process of oxygen, and the corrosion products contain γ‐FeOOH, Fe3O4 and small amounts of α‐FeOOH. Although rust formed had a double layer structure, the outer rust layer, which contained γ‐FeOOH and a little α‐FeOOH, was thin. The inner rust layer, containing Fe3O4, was the main component of the rust layer. Due to the weak acidity of RO product water, γ‐FeOOH can be transformed to Fe3O4 very quickly and Fe3O4 will accumulate on the metal surface. Because of the electrical conductivity and fractured surface of the Fe3O4 layer, the corrosion product layer cannot inhibit the corrosion process by hindering the diffusion process of oxygen, and hence the corrosion rate of carbon steel is always high.Originality/valueThe paper describes the first systematic research to be carried out on the corrosion behavior of carbon steel in RO product water. It was found that the generation and accumulation of Fe3O4 on the metal surface was the primary reason leading to the high corrosion rate of carbon steel, and anti‐corrosion measures can be chosen following the following rules: deoxygenation, raising of the pH of the solution, or addition of corrosion inhibitors to the solution.

“SMART” protective ability of water based epoxy coatings loaded with CaCO3 microbeads impregnated with corrosion inhibitors applied on AA2024 substrates

Corrosion protection of aluminium alloys often relies on the application of a coating on the metallic surface. The coating normally combines a barrier effect that restricts the ingress of corrosive species, with an inhibitive role induced by corrosion inhibitor pigments added to the coating formulation. However, the direct addition of corrosion inhibitors to the coating can cause some detrimental interactions between components, as well as formation of preferential electrolyte pathways, compromising the barrier properties. Moreover, electrolyte uptake and ageing may result in leaching of those corrosion inhibitors. In order to extend the corrosion inhibition ability of organic coatings one possible solution is to store the inhibitors inside nano or microreservoirs compatible with the coating matrix and able to sense the local changes induced by the corrosion process. This strategy has led to the development of a new generation of “smart” coatings for anti-corrosion purposes. The aim of this work is to study the anti-corrosion properties of water-based epoxy coatings loaded with pH sensitive particles, acting as feedback active containers for corrosion inhibitors and applied on the aluminium alloy AA2024-T3. For this purpose micron size calcium carbonate beads were modified with different corrosion inhibitors: cerium nitrate, salicylaldoxime and 2,5-dimercapto-1,3,4-thiadiazolate. These particles act as pH sensitive reservoirs because they dissolve at acidic pH, releasing the corrosion inhibitor, which then suppresses the corrosion activity of the bare metal. Electrochemical impedance spectroscopy (EIS) was used to estimate the electrical parameters assigned to the barrier properties of the coating and corrosion inhibition ability in the presence of inhibitor loaded calcium carbonate beads. The most relevant corrosion inhibition effects were observed from CaCO3 microbeads modified with cerium ions. The self healing potential of this new system was corroborated by localised electrochemical impedance measurements (LEIS).

Silica nanocontainers for active corrosion protection

Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl(-) concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings.

Encapsulation of triethanolamine as organic corrosion inhibitor into nanoparticles and its active corrosion protection for steel sheets

Triethanolamine (TEA), a corrosion inhibitor for zinc and steel, was introduced into nano-sized particles as nanoreservoirs to increase longevity of inhibitive property and prevent degradation caused by direct addition of corrosion inhibitor into coating layer. TEA-incorporated nanoparticles with average particle size around 400–450 nm were successfully synthesized by sequential emulsion polymerization, occupying around 5% of total solid weight of particles during a neutralization process. Encapsulated TEA was released from the capsule inside when the pH level of environment became acidic or alkaline due to an acid–base interaction or ionization of seed material in specific conditions. In the corrosion tests, the encapsulated TEA decreased the corrosion rate of steel substrate owing to its adsorption on steel surface and the resistance of coating layer against corrosive environment was much higher and remained its resistance as immersion time increased when TEA was incorporated in coating layer in the encapsulated form. Based on the scanning vibrating electrode technique (SVET) result, anticorrosive ability of the encapsulated TEA seemed to improve due to the spontaneous passivation of exposed metal on the defected region of coated steel.

Evaluation of corrosion inhibitors performance using real-time monitoring methods

The implementation of real-time corrosion-monitoring techniques can provide a reliable mechanism for detecting the overall effectiveness of chemical treatment programs and contribute to the selection and implementation of an adequate corrosion inhibitor system. Inadequate corrosion monitoring can result in an increase of both uniform and localized (pitting) corrosion activities which can lead to premature material failures. The present research was undertaken to ascertain whether linear polarization resistance (LPR), harmonic analysis (HA), and electrochemical noise (EN) in combination are suitable for the study of performance of corrosion inhibitors under a wide variety of conditions; for example, in the absence and the presence of hydrocarbons with or without the addition of corrosion inhibitors. The findings showed questionable results regarding the usefulness of the pitting factor derived from EN and HA data. In addition, statistical parameters were obtained, such as skew and kurtosis, and these results were compared with the pitting factor.

Effects of the Functional Groups of Complexing Agents and Cu Oxide Formation on Cu Dissolution Behaviors in Cu CMP Process

Cu dissolution behaviors with select reagents (malonic acid, glycine, malic acid, citric acid) were investigated in terms of the functional groups of complexing agents. Based on the results of Cu dissolution rate testing at various values, as well as UV–visible analysis with the addition of cupric ions, reaction mechanisms and effects of each functional group are proposed. The effect of Cu oxide formation on the Cu dissolution rate was also investigated by monitoring Cu dissolution rates with various concentrations and complexing agent concentrations. Additionally, the effect of the addition of corrosion inhibitor (5-aminotretrazole) on Cu dissolution was investigated. By combining the experimental results, we interpreted the Cu dissolution behaviors based on a competitive contribution from Cu oxide formation and complex formation between Cu (Cu oxide) and the complexing agent.

Effect of Antioxidants and Corrosion Inhibitor Additives on the Quenching Performance of Soybean Oil

Cooling curve analysis was used to evaluate the effect of corrosion inhibitor additives and antioxidants on the quenching properties of soybean oil. The results showed that addition of corrosion inhibitors provided significant changes in the cooling curve behavior and of the yellow metal corrosion inhibitors evaluated tolyltriazole exhibits the greatest rate acceleration of heat transfer. However, the presence of antioxidants did not exhibit a significant effect on quenching properties of soybean oil.

Electrochemical characterization of organic coatings for protection of historic steel artefacts

Electrochemical techniques are mainly known in the field of cultural heritage conservation as a tool for the elimination of corrosion layers or the removal of chlorides. However, these techniques are also a valuable tool for assessing the anti-corrosive efficiency of protective coatings. The aim of this study was to evaluate the performance of different coatings for their use in metallic heritage conservation using polarisation resistance (R p) and electrochemical impedance spectroscopy (EIS). Carbon steel samples were prepared to simulate the surface composition and morphology of historic steel artefacts, and coated by a conservator–restorer following the common practices in conservation treatments. Three commercial organic coatings have been studied: a microcrystalline wax (Renaissance™) and a methyl acrylate/ethyl methacrylate copolymer resin (Paraloid™ B-72) dissolved in acetone—both them commonly used in conservation and restoration treatments—and an ethylene copolymer wax emulsion in water (Poligen™ ES-91009) that has not been used so far for this purpose. Four commercial corrosion inhibitor additives were added to the Paraloid™ B-72 resin and Poligen™ ES-91009 wax. The additives were commercial preparations with the following known active components: a blend of triazoles (M435), an ammonium salt of tricarboxylic acid (M370), a calcium sulphonate (M109), and a bis-oxazoline (Alkaterge-T™). R p and EIS results showed that the best protection of the steel specimens was afforded by Poligen™ ES-91009 when applied in thick layers. None of the additives have shown a clear improvement of the protection properties of the coatings, and one of them impaired the barrier effect of the coating.

Corrosion Inhibition Effect of Dicycloimine Hydrochloride (DCI) on Mild Steel in 1M HCl

Addition of corrosion inhibitors is one of the widely used methods to control corrosion. In this work, an attempt has been made to explore the possibility of using dicycloimine hydrochloride (DCI) as an inhibitor on mild steel in 1 M HCl. The inhibition efficiency of DCI has been evaluated by conventional weight loss method and electrochemical polarization studies. Experimental results are fitted to various adsorption isotherms. Thermodynamic parameters have also been studied from temperature studies. The results reveal that DCI acts as an effective inhibitor (around 90% of IE) in HCl media.

Evolution of corrosion protection for sol–gel coatings doped with inorganic inhibitors

One the way to improve the self-repair properties of sol–gel films on aluminium alloy is the addition of corrosion inhibitors which could be released from the coating, minimising the corrosion of the unprotected area. Environmentally friendly corrosion inhibitors are studied (chromium III, molybdate, permanganate and cerium III) and compared to the standard corrosion inhibitor, i.e. hexavalent chromium. Corrosion performances are studied by polarisation resistance (Rp) in chloride medium. Evolution of composition of sol–gel coatings, during the corrosion test, is examined by GDOES (glow discharge optical emission spectroscopy). The results show that the morphology of sol–gel and the solubility of the additive play a role in the effectiveness of corrosion protection for a long term. Additives such as molybdate and permanganate ions decrease the sol–gel network stability and are too soluble (they are rapidly lost from the sol–gel films, in an aggressive medium), decreasing the power to prevent corrosion. Incorporation of Ce III is not efficient for a long time due to its high solubility. Sol–gel films containing Cr VI and Cr III provide adequate corrosion protection, due to the sol–gel stability and their low solubility.

Experimental study of high-temperature foam for acid diversion

Foam treatments are used worldwide for acid diversion in matrix acid well stimulation. Many field treatments require foam effectiveness at elevated temperature in the presence of both acid and corrosion inhibitor. This study examines four surfactant formulations at room temperature, 104 °C (220 °F) and 204 °C (400 °F), with and without acid and corrosion inhibitor. The surfactants included amphoteric as well as nonionic foaming agents. The acid formulation was a mixture of chelating agent and HCl, with pH about 4. Formulations were tested at all three temperatures for foaming with N 2 gas (80% quality) at back-pressure of 600 psi (4.1 MPa) in sandpacks and for bulk-foam stability in a pressure cell. Foam was created in most cases at 24 °C (75 °F) without acid or corrosion inhibitor. Creating foam with acid and corrosion inhibitor at 204 °C was more difficult, requiring higher injection rates and lower foam quality. Once formed, strong foam had higher mobility at elevated temperatures than at room temperature. Addition of corrosion inhibitor was more adverse to foaming than acid itself. At 204 °C foam propagation was slower, and steady-state pressure gradient was lower, than at 24 °C. The two steady-state strong-foam regimes reported elsewhere were present at 104 °C and in the presence of acid. Pressure gradient at 104 °C was lower in both high-quality and low-quality foam regimes. The bulk-foam stability results agree qualitatively with the sandpack results, but quantitative relationships between the two tests are hard to draw. These results also suggest that these surfactants may degrade over a period of time, for example, a couple of hours at 204 °C. Residence time in the heated sandpack therefore should be properly accounted for in design of experiments. These results are consistent with decreasing foam stability at higher temperature; adverse interactions between foaming surfactant and inhibitor; easier foam generation and propagation at higher velocity and lower foam quality; and greater difficulty in creating foam under conditions that reduce steady-state foam strength. These results can aid design of high-temperature foam-acid diversion treatments.

Study on Mechanism of Hydrogen Generation from Lubricants

To establish fundamental countermeasures for hydrogen embrittlement that occurs to several kinds of bearings, the mechanism of hydrogen generation from lubricants was studied. Sliding tests were conducted, and the amount of hydrogen generated from several kinds of lubricants during sliding was measured. It is concluded that the lubricant is decomposed and hydrogen is generated through a catalytic reaction with the fresh steel surface. The amount of hydrogen generated from each lubricant depends on its lubricity, not on its chemical structure. It is also confirmed that the lubricant with the larger wear brings more generated hydrogen into steel. Based on the above mechanism of hydrogen generation, methods of inhibiting hydrogen brittle flaking with additives were investigated. It is clarified that the addition of corrosion inhibitors that form a passive state film on the steel surface effectively inhibits generation of hydrogen from lubricants and penetration of hydrogen into steel. Presented at the STLE Annual Meeting in Las Vegas, Nevada May 15-19, 2005 Review led by Lois Gschwender

Effects of addition of corrosion inhibitors to silane films on the performance of AA2024-T3 in a 0.5 M NaCl solution

Water-based organofunctional silanes have been successfully used as an alternative to toxic chromate coatings for surface pre-treatment of metals and alloys. To further improve the performance of these silane films, corrosion inhibitors were added to the silane films and their corrosion properties investigated in 0.5 M NaCl solution. The inhibitors used were environmentally acceptable organic (tolyltriazole, benzotriazole) molecules and inorganic cerium salts. In the first part of the paper we discuss the inhibition efficiency of the individual inhibitor on the corrosion of AA2024-T3 alloy to understand the mechanisms of inhibition offered by these inhibitors. All of the above mentioned inhibitors effectively protected AA2024-T3 alloy against corrosion when immersed in a 0.5 M NaCl solution containing these inhibitors. In the second part of the paper the effects of the addition of inhibitors to silane films was investigated. The results indicate that these inhibitors are slowly leached out and thus further improve the corrosion protection by silane films and the inorganic inhibitors show promise of self-healing of defects.

Microbial Corrosion of Protective Coatings

Research studies have shown that protective coatings of diverse chemical composition represent a powerful factor stimulating the bacterial activity of corrosion inducers. On the film and mastic coatings investigated in the present paper, bacterial communities are formed, which consist of bacteria of various ecological trophic groups. Bacteria in a biofilm are characterised by high metabolic activity and the ability to destroy traditional coatings. As a result of microbial destruction, the physical mechanical and chemical properties of a material undergo significant changes. The characteristics of strength, elasticity and adhesion deteriorate, thus degrading the main function of the coatings, i.e.protection of metal against corrosion. An efficient method of protection against biodeterioration is the addition of corrosion inhibitors with biocide action into their composition. It was established that the population of bacteria on oil bitumen coatings modified by antimicrobial bonds is 1–4 orders lower than on materials with no such additives. Protection of underground structures against corrosion should be performed comprehensively with consideration of the biocorrosivity of soils and bioresistance of coatings.

A new method of studying buried steel corrosion and its inhibition using the wire beam electrode

An electrochemically integrated multi-electrode system namely the wire beam electrode (WBE) has been applied for the first time to study corrosion of mild steel buried in sand, with and without the presence of corrosion inhibitor potassium dichromate (K 2Cr 2O 7). Measurements of galvanic current distribution maps have been carried out during the exposure of the WBE to dry, damp and chlorinated sand environments. Characteristic changes in galvanic current distribution maps have been observed during the initiation and propagation of localised corrosion. Specifically, during corrosion initiation in damped sand, new anodes were found to initiate and corrosion appeared to be in general form. When the WBE was later exposed to chlorinated sand, massive disappearance of anodic sites was found to occur, resulting in accelerated anodic dissolution of a small number of remaining anodic sites. Addition of corrosion inhibitor K 2Cr 2O 7 to the sand environment was found to significantly reduce galvanic current only after an initial increase in galvanic current. This result suggests that K 2Cr 2O 7 behaved as an anodic inhibitor.

Comparison of Techniques for Monitoring Corrosion Inhibitors in Oil and Gas Pipelines

Abstract Addition of corrosion inhibitors is one of the common methods to control both general and pitting corrosion of oil and gas pipelines. Development of an integrity management program to control internal corrosion of such pipelines depends on our ability to monitor the efficiency of the inhibitor performance. Monitoring in an oil and gas pipeline is a complex process due to the multitude of conditions that exist in such an environment. In this paper, the reliability of weight loss, linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrochemical noise (EN), and externally mounted hydrogen probes for monitoring inhibitor performance in oil and gas pipelines is investigated.

Corrosion inhibited metal pigments

Flake-shaped particles of aluminium are well known in the coatings and printing ink industry as “silver bronze pigments”. For their use in waterborne coatings or outdoor applications, an effective corrosion protection of the highly reactive aluminium surfaces is required. The traditional stabilization techniques for aluminium pigments are based on the addition of corrosion inhibitors or on chromate passivation. This publication presents new developments in the encapsulation of metallic pigments that are based on modern sol-gel techniques. All products are heavy metal-free and provide excellent applicational properties.

Stabilization of aluminum pigment in waterborne paints

The corrosion of aluminum pigments in aqueous alkaline paint media, which results in the evolution of hydrgen, can be inhibited by certain substances. The combination of noninhibiting paint resins with three corrosion inhibitors (salicylic acid, a fluorinated phosphate surfactant, and an epoxy ester resin) has been studied. The presence of the resins does not significantly affect the stabilization of the aluminum pigment at pH 10 by the corrosion inhibitors. With the addition of corrosion inhibitors, the hydrogen volume evolved from aqueous aluminum pigment dispersions is surprisingly reduced by stirring. However, when heated to +40°C aqueous aluminum pigment dispersions with inhibitors evolve more hydrogen; at pH 8 the results are still satisfactory even at +40°C.

K-0910 低炭素鋼の腐食に伴うアコースティック・エミッションの発生(G04-3 破壊ほか)(G04 機械材料・材料加工部門一般講演)

In order to investigate the acoustic emmision (AE) caused by corrosion, AE was measured for the specimens of SS400 mild steel, zinc-plated steel, and SUS304 stainless steel immersed in 0.5kmol/m^3 H_2SO_4 aqueous solution. AE was detected immeadiately after poring the solutions into a cell. The total count of AE increased proportionaly with the immersion time. The generation of AE was remarkable in the order of SUS304 stainless steel < SS400 mild steel < zinc-plated steel. This order corresponds to that in corrosion rate. In addition, AE count was increased by anodic polarization, and decreased by the addition of corrosion inhibitor. These results imply that corrosion produces the AE.