WorldWideScience

Sample records for corrosion protective coating

  1. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  2. 49 CFR 192.461 - External corrosion control: Protective coating.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion control...

  3. Corrosion protective coating for metallic materials

    Science.gov (United States)

    Buchheit, Rudolph G.; Martinez, Michael A.

    1998-01-01

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds.

  4. Corrosion protective coating for metallic materials

    Science.gov (United States)

    Buchheit, R.G.; Martinez, M.A.

    1998-05-26

    Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

  5. Self-Healing Corrosion Protective Sol-Gel Coatings

    NARCIS (Netherlands)

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic

  6. Smart Coatings for Launch Site Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.

    2014-01-01

    Smart, environmentally friendly paint system for early corrosion detection, mitigation, and healing that will enable supportability in KSC launch facilities and ground systems through their operational life cycles. KSC's Corrosion Technology Laboratory is developing a smart, self-healing coating that can detect and repair corrosion at an early stage. This coating is being developed using microcapsules specifically designed to deliver the contents of their core when corrosion starts.

  7. Accelerated Test Method for Corrosion Protective Coatings Project

    Science.gov (United States)

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  8. Microencapsulation Technologies for Corrosion Protective Coating Applications

    Science.gov (United States)

    Li, Wenyan; Buhrow, Jerry; Jolley, Scott; Calle, Luz; Pearman, Benjamin; Zhang, Xuejun

    2015-01-01

    Microencapsulation technologies for functional smart Coatings for autonomous corrosion control have been a research area of strong emphasis during the last decade. This work concerns the development of pH sensitive micro-containers (microparticles and microcapsules) for autonomous corrosion control. This paper presents an overview of the state-of-the-art in the field of microencapsulation for corrosion control applications, as well as the technical details of the pH sensitive microcontainer approach, such as selection criteria for corrosion indicators and corrosion inhibitors; the development and optimization of encapsulation methods; function evaluation before and after incorporation of the microcontainers into coatings; and further optimization to improve coating compatibility and performance.

  9. Evaluation of several corrosion protective coating systems on aluminum

    Science.gov (United States)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  10. Chemical conversion coating for protecting magnesium alloys from corrosion

    Science.gov (United States)

    Bhargava, Gaurang; Allen, Fred M.; Skandan, Ganesh; Hornish, Peter; Jain, Mohit

    2016-01-05

    A chromate-free, self-healing conversion coating solution for magnesium alloy substrates, composed of 10-20 wt. % Mg(NO.sub.3).sub.2.6H.sub.2O, 1-5 wt. % Al(NO.sub.3).sub.3.9H.sub.2O, and less than 1 wt. % of [V.sub.10O.sub.28].sup.6- or VO.sub.3.sup.- dissolved in water. The corrosion resistance offered by the resulting coating is in several hundreds of hours in salt-spray testing. This prolonged corrosion protection is attributed to the creation of a unique structure and morphology of the conversion coating that serves as a barrier coating with self-healing properties. Hydroxoaluminates form the backbone of the barrier protection offered while the magnesium hydroxide domains facilitate the "slow release" of vanadium compounds as self-healing moieties to defect sites, thus providing active corrosion protection.

  11. Renewal of corrosion protection of coated aluminum after welding

    Science.gov (United States)

    Higgins, R. H.

    1969-01-01

    Effectiveness of conversion coatings designed to protect aluminum alloys against atmospheric corrosion is reduced after exposure to high temperature or welding. Damaged coating should be manually stripped six inches from the weld and then recoated by sponge or spray with the original solution.

  12. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Science.gov (United States)

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    indicators, inhibitors and self-healing agents. This allows the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods.Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The release of the inhibitors from the microparticles in basic solution was studied. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed.The inhibition efficacy of the inhibitors, incorporated directly and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

  13. Benchmarking of Zinc Coatings for Corrosion Protection: A Detailed Characterization of Corrosion and Electrochemical Properties of Zinc Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wijesinghe, Sudesh L; Zixi, Tan [Singapore Institute of Manufacturing Technology, Nanyang Drive (Singapore)

    2017-02-15

    Due to various types of Zn coatings for many decades for various applications, it is imperative to study and compare their corrosion resistance properties of some of these. Here, we introduce a systematic methodology for evaluation and validation of corrosion protection properties of metallic coatings. According to this methodology, samples are were exposed in an advanced cyclic corrosion test chamber according to ISO 14993, and removed at the end of each withdrawal for respective corrosion and electrochemical characterization to evaluate both barrier and galvanic protection properties. Corrosion protection properties of coatings were evaluated by visual examination according to ISO 10289, mass loss and subsequent corrosion rate measurements, electrochemical properties, and advanced electrochemical scanning techniques. In this study, corrosion protection properties of a commercial zinc rich coating (ZRC) on AISI 1020 mild steel substrates were evaluated and benchmarked against hot dip galvanized (HDG). Results were correlated, and corrosion protection capabilities of the two coatings were compared. The zinc rich coating performed better than hot dip galvanized coating in terms of overall corrosion protection properties, according to the exposure and experimental conditions used in this study. It proved to be a suitable candidate to replace hot dip galvanized coatings for desired applications.

  14. High performance polypyrrole coating for corrosion protection and biocidal applications

    Science.gov (United States)

    Nautiyal, Amit; Qiao, Mingyu; Cook, Jonathan Edwin; Zhang, Xinyu; Huang, Tung-Shi

    2018-01-01

    Polypyrrole (PPy) coating was electrochemically synthesized on carbon steel using sulfonic acids as dopants: p-toluene sulfonic acid (p-TSA), sulfuric acid (SA), (±) camphor sulfonic acid (CSA), sodium dodecyl sulfate (SDS), and sodium dodecylbenzene sulfonate (SDBS). The effect of acidic dopants (p-TSA, SA, CSA) on passivation of carbon steel was investigated by linear potentiodynamic and compared with morphology and corrosion protection performance of the coating produced. The types of the dopants used were significantly affecting the protection efficiency of the coating against chloride ion attack on the metal surface. The corrosion performance depends on size and alignment of dopant in the polymer backbone. Both p-TSA and SDBS have extra benzene ring that stack together to form a lamellar sheet like barrier to chloride ions thus making them appropriate dopants for PPy coating in suppressing the corrosion at significant level. Further, adhesion performance was enhanced by adding long chain carboxylic acid (decanoic acid) directly in the monomer solution. In addition, PPy coating doped with SDBS displayed excellent biocidal abilities against Staphylococcus aureus. The polypyrrole coatings on carbon steels with dual function of anti-corrosion and excellent biocidal properties shows great potential application in the industry for anti-corrosion/antimicrobial purposes.

  15. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    Science.gov (United States)

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Coatings for Oxidation and Hot Corrosion Protection of Disk Alloys

    Science.gov (United States)

    Nesbitt, Jim; Gabb, Tim; Draper, Sue; Miller, Bob; Locci, Ivan; Sudbrack, Chantal

    2017-01-01

    Increasing temperatures in aero gas turbines is resulting in oxidation and hot corrosion attack of turbine disks. Since disks are sensitive to low cycle fatigue (LCF), any environmental attack, and especially hot corrosion pitting, can potentially seriously degrade the life of the disk. Application of metallic coatings are one means of protecting disk alloys from this environmental attack. However, simply the presence of a metallic coating, even without environmental exposure, can degrade the LCF life of a disk alloy. Therefore, coatings must be designed which are not only resistant to oxidation and corrosion attack, but must not significantly degrade the LCF life of the alloy. Three different Ni-Cr coating compositions (29, 35.5, 45wt. Cr) were applied at two thicknesses by Plasma Enhanced Magnetron Sputtering (PEMS) to two similar Ni-based disk alloys. One coating also received a thin ZrO2 overcoat. The coated samples were also given a short oxidation exposure in a low PO2 environment to encourage chromia scale formation. Without further environmental exposure, the LCF life of the coated samples, evaluated at 760C, was less than that of uncoated samples. Hence, application of the coating alone degraded the LCF life of the disk alloy. Since shot peening is commonly employed to improve LCF life, the effect of shot peening the coated and uncoated surface was also evaluated. For all cases, shot peening improved the LCF life of the coated samples. Coated and uncoated samples were shot peened and given environmental exposures consisting of 500 hrs of oxidation followed by 50 hrs of hot corrosion, both at 760C). The high-Cr coating showed the best LCF life after the environmental exposures. Results of the LCF testing and post-test characterization of the various coatings will be presented and future research directions discussed.

  17. Corrosion protection performance of corrosion inhibitors and epoxy-coated reinforcing steel in a simulated concrete pore water solution.

    Science.gov (United States)

    1998-06-01

    We used a simulated concrete pore water solution to evaluate the corrosion protection performance of concrete corrosion-inhibiting admixtures and epoxy-coated reinforcing bars (ECR). We evaluated three commercial corrosion inhibitors, ECR from three ...

  18. Thin Glass Coatings for the Corrosion Protection of Metals

    DEFF Research Database (Denmark)

    Lampert, Felix

    This dissertation presents the research work aimed at developing functional submicrometer thick SiOx barrier coatings for the corrosion protection of stainless steel substrates in chloride containing media, which may enable the use of stainless steels as plate material for marine heat exchangers...... with localized corrosion and do not impact the heat transfer or the component performance. The herein presented approach focuses primarily on the formation of SiOx-like thin films from Hydrogen Silsesquioxane (HSQ) –based “spin-on-glass” (SOG) precursor. The technology is well known for the deposition...... in corrosion sensitive applications. Since the deposition of SiOx thin films is a well-established technology, the SOG technology was directly benchmarked to PVD-based SiO2 coatings. The coating adhesion was assessed by cross cut testing and increasing load scratch testing and the efficiency of the sub...

  19. Mullite coatings for corrosion protection of silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Mulpuri, R.; Sarin, V.K. [Boston Univ., MA (United States)

    1995-08-01

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can satisfy the stringent requirements imposed by such applications. Chemical Vapor Deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and a good coefficient of thermal expansion match with SiC are being investigated as a potential candidate. Since mullite has never been successfully grown via CVD, the thermodynamics and kinetics of its formation were initially established and used as a guideline in determining the initial process conditions. Process optimization was carried out using an iterative process of theoretical analysis and experimental work coupled with characterization and testing. The results of theoretical analysis and the CVD formation characteristics of mullite are presented.

  20. Corrosion Protection of Steels by Conducting Polymer Coating

    Directory of Open Access Journals (Sweden)

    Toshiaki Ohtsuka

    2012-01-01

    Full Text Available The corrosion protection of steels by conducting polymer coating is reviewed. The conducting polymer such as polyaniline, polypyrrole, and polythiophen works as a strong oxidant to the steel, inducing the potential shift to the noble direction. The strongly oxidative conducting polymer facilitates the steel to be passivated. A bilayered PPy film was designed for the effective corrosion protection. It consisted of the inner layer in which phosphomolybdate ion, PMo12O3−40 (PMo, was doped and the outer layer in which dodecylsulfate ion (DoS was doped. The inner layer stabilized the passive oxide and the outer possessed anionic perm-selectivity to inhibit the aggressive anions such as chloride from penetrating through the PPy film to the substrate steel. By the bilayered PPy film, the steel was kept passive for about 200 h in 3.5% sodium chloride solution without formation of corrosion products.

  1. Corrosion-Protection Coatings for Aluminum

    Science.gov (United States)

    Higgins, R. H.

    1983-01-01

    Study investigates 21 combinatios of surface treatments, primers and topcoats. Study considers several types of coatings, including primers, enamels, chlorinated rubbers, alkyds, epoxies, vinyls, polyurethanes, waterbased paints, and antifouling paints. 20-page report summarizes the study.

  2. Modified corrosion protection coatings for Concrete tower of Transmission line

    Science.gov (United States)

    Guo, Kai; Jing, Xiangyang; Wang, Hongli; Yue, Zengwu; Wu, Yaping; Mi, Xuchun; Li, Xingeng; Chen, Suhong; Fan, Zhibin

    2017-12-01

    By adding nano SiO2 particles, an enhanced K-PRTV anti-pollution flashover coating had been prepared. Optical profile meter (GT-K), atomic force microscopy (AFM) and infrared spectrometer (FT-IR) characterization were carried out on the coating surface analysis. With the use of modified epoxy resin as the base material, the supplemented by phosphate as a corrosion stabilizer, to achieve a corrosion of steel and galvanized steel with rust coating. Paint with excellent adhesion, more than 10MPa (1), resistant to neutral salt spray 1000h does not appear rust point. At the same time coating a large amount of ultra-fine zinc powder can be added for the tower galvanized layer zinc repair function, while the paint in the zinc powder for the tower to provide sacrificial anode protection, to achieve self-repair function of the coating. Compared to the market with a significant reduction in the cost of rust paint, enhance the anti-corrosion properties.

  3. Corrosion protection service life of epoxy-coated reinforcing steel in Virginia bridge decks.

    Science.gov (United States)

    2003-01-01

    The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare steel bars from 10 Virginia bridge decks built between 1981 and 1995. The objective was to determine the corrosion p...

  4. Regenerative nano-hybrid coating tailored for autonomous corrosion protection.

    Science.gov (United States)

    Tran, The Hai; Vimalanandan, Ashokanand; Genchev, Georgi; Fickert, Johannes; Landfester, Katharina; Crespy, Daniel; Rohwerder, Michael

    2015-07-01

    A novel bilayer coating system for autonomous corrosion-triggered self-healing is demonstrated. The storage of the encapsulated monomer and the catalyst is separated in two different layers. The encapsulated catalyst is stored inside a metallic coating, which ensures its activity even for an extended exposure time. The release from the capsules is triggered by corrosion and the correlated pH increase. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Low Temperature Curing of Hydrogen Silsesquioxane Surface Coatings for Corrosion Protection of Aluminum

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Møller, Per

    2016-01-01

    Hydrogen Silsesquioxane (HSQ) has shown to be a promising precursor for corrosion protective glass coatings for metallic substrates due to the excellent barrier properties of the films, especially in the application of protective coatings for aluminum in the automotive industry where high chemical...... on aluminum substrates to evaluate the adhesion and corrosion resistance of the films....

  6. Corrosion Protection Performance of Polyester-Melamine Coating with Natural Wood Fiber Using EIS Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shin, PyongHwa; Shon, MinYoung [Pukyong National University, Busan (Korea, Republic of); Jo, DuHwan [POSCO, Gwangyang (Korea, Republic of)

    2016-04-15

    In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

  7. Silicone coating systems to improve corrosion protection of steel; Silikonbeschichtungssysteme zur Verbesserung des Korrosionsschutzes von Stahl

    Energy Technology Data Exchange (ETDEWEB)

    Kucharczyk, P.; Fachinger, J.; Odoj, R. [Forschungszentrum Juelich GmbH (Germany); Boehnert, R. [Fachhochschule Koeln (Germany)

    2006-06-15

    Due to German policy an interim storage of radioactive waste during additional 30 years is needed. This requires a high standard of storage containers especially in terms of corrosion resistance. Silicon elastomers (polysiloxanes) have favourable physical and chemical properties and seem to be appropriate for either outer or inner coating of storage containers. In this paper corrosion protection of different silicon coating systems has been investigated. The addition-curing polysiloxane RT622 (Wacker Chemie) was used for experiments. This is a low-viscosity material that could be modified by corrosion protecting pigments like zinc powder and micaceous iron ore. The pigment coatings assured better corrosion protection than unmodified silicon covering. Furthermore, the zinc powder caused the most notable improvement of corrosion protection. The best coating system consisted of a zinc paint and a polysiloxane coating. (orig.)

  8. Corrosion protection performance of porous strontium hydroxyapatite coating on polypyrrole coated 316L stainless steel.

    Science.gov (United States)

    Gopi, D; Ramya, S; Rajeswari, D; Kavitha, L

    2013-07-01

    Polypyrrole/strontium hydroxyapatite bilayer coatings were achieved on 316L stainless steel (316L SS) by the electropolymerisation of pyrrole from sodium salicylate solution followed by the electrodeposition of porous strontium hydroxyapatite. The formation and the morphology of the bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM), respectively. The corrosion resistance of the coated 316L SS specimens was investigated in Ringer's solution by electrochemical techniques and the results were substantiated with inductively coupled plasma atomic emission spectrometry (ICP-AES). The passive film underneath the polypyrrole layer is effective in protecting 316L SS against corrosion in Ringer's solution. Moreover, we believe that the top porous strontium hydroxyapatite layer can provide potential bioactivity to the 316L SS. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Multilayered Zn-Ni alloy coatings for better corrosion protection of mild steel

    Directory of Open Access Journals (Sweden)

    Sadananda Rashmi

    2017-06-01

    Full Text Available A simple aqueous electrolyte for the deposition of anti-corrosive Zn-Ni alloy coatings was optimized using conventional Hull cell method. The corrosion protection value of the electrodeposited coatings at a current density (c.d. range of 2.0–5.0 A dm−2 has been testified in 5 wt% NaCl solution, as representative corrosion medium. The electrochemical behavior of the coatings towards corrosion was related to its surface topography, elemental composition and phase structure using scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD analyses, respectively. Among the monolithic coatings developed at different c.d.’s, the coating obtained at 3.0 A dm−2 was found to be the best with least corrosion current (icorr value. Further, the corrosion protection efficacy of the monolayer coatings were improved to many folds through multilayer coating approach, by modulating the cyclic cathode current densities (CCCD’s. The composition modulated multilayer (CMM Zn-Ni alloy coating with 60 layers, developed from the combination of CCCD’s 3.0 and 5.0 A dm−2 was found to be the best with 3 fold enhancement in corrosion protection efficiency. The formation of multilayer coatings was confirmed using cross-sectional SEM, and the experimental results are discussed with tables and figures.

  10. Corrosion protection of Mg/Al alloys by thermal sprayed aluminium coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A., E-mail: anpardo@quim.ucm.es [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Casajus, P.; Mohedano, M.; Coy, A.E.; Viejo, F. [Departamento de Ciencia de Materiales, Facultad de Quimicas, Universidad Complutense, 28040 Madrid (Spain); Torres, B. [Departamento de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, 28933 Mostoles, Madrid (Spain); Matykina, E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2009-05-15

    The protective features of thermal sprayed Al-coatings applied on AZ31, AZ80 and AZ91D magnesium/aluminium alloys were evaluated in 3.5 wt.% NaCl solution by electrochemical and gravimetric measurements. The changes in the morphology and corrosion behaviour of the Al-coatings induced by a cold-pressing post-treatment were also examined. The specimens were characterized by scanning electron microscopy, energy dispersive X-ray analysis and low-angle X-ray diffraction. The as-sprayed Al-coatings revealed a high degree of porosity and poor corrosion protection, which resulted in galvanic acceleration of the corrosion of the magnesium substrates. The application of a cold-pressing post-treatment produced more compact Al-coatings with better bonding at the substrate/coating interface and higher corrosion resistance regardless of the nature of the magnesium alloy.

  11. An alternate to chromate conversion coatings for the corrosion protection of aluminum 2024-T3

    Science.gov (United States)

    Guo, Ruiguang

    Corrosion of high-strength aluminum alloys used for airspace application is an expensive and serious problem. The most significant environmental factor contributing to the corrosion of these alloys is water condensed from humid air and contaminated with soluble chloride salts. The Al 2024 series used for aircraft are particularly susceptible to corrosion in aqueous chloride solutions due to alloying constituents such as copper and other impurities. Chromates are efficient inhibitors of corrosion of aluminum in near neutral aqueous environments containing aggressive anions such as chlorides. Usually, aluminum alloys are initially protected by chromate conversion coatings. Additional polymer coatings are sometimes added during exposure to corrosive atmospheres such as marine environments. Although chromate coatings are widely used, they require the use of noxious solutions, so they have always presented effluent disposal problems. There are health and safety concerns over the use of chromates due to their toxicity and carcinogenic nature and, as a consequence, the environmental and health risks associated with the use of such coatings will be restricted in the future. It was these health and safety concerns that led to the development of alternative non-toxic coating processes with comparable adhesion properties and corrosion protection. A variety of process technologies are under development and are vying for acceptance in industrial markets. As an alternate conversion coating, a new titanate conversion coating was systematically researched and developed. Research concentrated on producing passive surfaces from a simple titanate solution using an immersion process. The corrosion resistance of the treated surface has been evaluated using simple, rapid electrochemical techniques as well as a more long-term salt spray test. Passivation by titanate conversion treatment exhibits many similarities to chromate conversion treatment. Based on this study of corrosion

  12. A shape-recovery polymer coating for the corrosion protection of metallic surfaces.

    Science.gov (United States)

    Lutz, Alexander; van den Berg, Otto; Van Damme, Jonas; Verheyen, Karen; Bauters, Erwin; De Graeve, Iris; Du Prez, Filip E; Terryn, Herman

    2015-01-14

    Self-healing polymer coatings are a type of smart material aimed for advanced corrosion protection of metals. This paper presents the synthesis and characterization of two new UV-cure self-healing coatings based on acrylated polycaprolactone polyurethanes. On a macroscopic scale, the cured films all show outstanding mechanical properties, combining relatively high Young's modulus of up to 270 MPa with a strain at break above 350%. After thermal activation the strained films recover up to 97% of their original length. Optical and electron microscopy reveals the self-healing properties of these coatings on hot dip galvanized steel with scratches and microindentations. The temperature-induced closing of such defects restores the corrosion protection and barrier properties of the coating as shown by electrochemical impedance spectroscopy and scanning vibrating electrode technique. Therefore, such coatings are a complementary option for encapsulation-based autonomous corrosion protection systems.

  13. Cerium oxide as conversion coating for the corrosion protection of aluminum

    Directory of Open Access Journals (Sweden)

    JELENA GULICOVSKI

    2013-11-01

    Full Text Available CeO2 coatings were formed on the aluminum after Al surface preparation, by dripping the ceria sol, previously prepared by forced hydrolysis of Ce(NO34. The anticorrosive properties of ceria coatings were investigated by the electrochemical impedance spectroscopy (EIS during the exposure to 0.03 % NaCl. The morphology of the coatings was examined by the scanning electron microscopy (SEM. EIS data indicated considerably larger corrosion resistance of CeO2-coated aluminum than for bare Al. The corrosion processes on Al below CeO2 coating are subjected to more pronounced diffusion limitations in comparison to the processes below passive aluminum oxide film, as the consequence of the formation of highly compact protective coating. The results show that the deposition of ceria coatings is an effective way to improve corrosion resistance for aluminum.

  14. The corrosion protection of 6061-T6 aluminum by a polyurethane-sealed anodized coat

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    The corrosion protection of 6061-T6 anodized aluminum afforded by a newly patented polyurethane seal was studied using the ac impedance technique. Values of the average corrosion rates over a 27-day exposure period in 3.5 percent NaCl solutions at pH 5.2 and pH 9.5 compared very favorably for Lockheed-prepared polyurethane-sealed and dichromate-sealed coats of the same thickness. Average corrosion rates for both specimens over the first 7 days of exposure compared well with those for a hard anodized, dichromate-sealed coat, but rose well above those for the hard anodized coat over the entire 27-day period. This is attributed both to the greater thickness of the hard anodized coat, and possibly to its inherently better corrosion protective capability.

  15. Corrosion protection of iron using porous anodic oxide/conducting polymer composite coatings.

    Science.gov (United States)

    Konno, Yoshiki; Tsuji, Etsushi; Aoki, Yoshitaka; Ohtsuka, Toshiaki; Habazaki, Hiroki

    2015-01-01

    Conducting polymers (CPs), including polypyrrole, have attracted attention for their potential in the protection of metals against corrosion; however, CP coatings have the limitation of poor adhesion to metal substrates. In this study, a composite coating, comprising a self-organized porous anodic oxide layer and a polypyrrole layer, has been developed on iron. Because of electropolymerization in the pores of the anodic oxide layer, the composite coating showed improved adhesion to the substrate along with prolonged corrosion protection in a NaCl aqueous corrosive environment. The anodic oxide layers are formed in a fluoride-containing organic electrolyte and contain a large amount of fluoride species. The removal of these fluoride species from the oxide layer and the metal/oxide interface region is crucial for improving the corrosion protection.

  16. Enhanced corrosion protective PANI-PAA/PEI multilayer composite coatings for 316SS by spin coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Junaid Ali; Lu, Hongbin; Tang, Shaochun; Meng, Xiangkang, E-mail: mengxk@nju.edu.cn

    2015-01-15

    Highlights: • PANI-PAA/PEI multilayers with controllable thickness were fabricated by spin assembly. • PAA matrix results in the homogeneous dispersion of PANI in the composite coatings. • Spin coating combined with heating assures the linear increase in thickness with n. • The corrosion protection property of PANI-PAA/PEI coatings were optimized at n = 20. • Enhanced protection owing to multilayer structure that lengthens the diffusion pathway of ions. - Abstract: In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

  17. Enhanced corrosion protective PANI-PAA/PEI multilayer composite coatings for 316SS by spin coating technique

    Science.gov (United States)

    Syed, Junaid Ali; Lu, Hongbin; Tang, Shaochun; Meng, Xiangkang

    2015-01-01

    In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

  18. Electrochemical investigation of powder coatings and their application to magnesium-rich primers for corrosion protection

    Science.gov (United States)

    Orgon, Casey Roy

    Corrosion is the decomposition of metal and metal alloys which threatens the integrity of man-made structures. One of the more efficient methods of delaying the corrosion process in metals is by coatings. In this work, the durability of two polyester powder coatings were investigated for corrosion protection of AA-2024-T3. Polyester powder coatings crosslinked by either triglycidyl isocyanurate (TGIC) or beta-hydroxyalkyl amide (HAA) compounds were prepared and investigated for barrier protection of metal substrates by electrochemical impedance spectroscopy (EIS). Polyester-TGIC coatings were found to provide better long-term protection, which can be attributed to the increased mechanical strength and higher concentration of crosslinking in the coating films. Additionally, the polyester powder coatings, along with a fusion bonded epoxy (FBE) were investigated for their compatibility as a topcoat for magnesium-rich primers (MgRP). Under proper application conditions, powder topcoats were successfully applied to cured MgRP while corrosion protection mechanisms of each system were maintained.

  19. Ion Vapour Deposited (IVD) Aluminium Coatings for the Corrosion Protection of High Strength Steel

    Science.gov (United States)

    1991-04-01

    iron rust is detected within many of the pits (Figure 17). This rust forms as the aluminium loses its effectiveness to act as a sacrificial anode ...Cadmium possesses a low rate of corrosion and is therefore a very durable coating. It also provides sacrificial corrosion protection to the underlying...appeared to be remnants of rust (Figure 11). Energy dispersive X- Ray analysis identified silicon, aluminium, iron, manganese and calcium in this

  20. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Shihui [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Chen, Cheng; Cui, Mingjun [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Li, Wei [Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211 (China); Zhao, Haichao, E-mail: zhaohaichao@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201 (China)

    2017-06-15

    Highlights: • Self-dopedpolyaniline (SPANi) with good conductivity and dispersibility in water was copolymerized by aniline and its derivative. • Environmental friendly SPANi/epoxy composite coating with remarkable anti-corrosion performance was prepared. • The corrosion product of pure epoxy or composite coating was characterized by X-ray diffraction pattern and scanning electron microscope (SEM). - Abstract: Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV–vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  1. Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

    Science.gov (United States)

    Oksa, M.; Metsäjoki, J.; Kärki, J.

    2015-01-01

    There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

  2. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  3. Vacuum Sputtered and Ion-Plated Coatings for Wear and Corrosion Protection

    Science.gov (United States)

    Spalvins, T.

    1982-01-01

    The plasma or ion-assisted coating techniques such as sputtering and ion plating are discussed in view of wear and corrosion protection. The basic processes and the unique features of the technique are discussed in regard to the synthesis and development of high reliability wear and corrosion resistant films. The ions of the plasma which transfer energy, momentum, and charge to the substrate and the growing films can be beneficially used. As a result, coating adherence and cohesion is improved. Favorable morphological growth such as high density and porosity-free films can be developed, and residual stresses can be reduced.

  4. A polyaniline based intrinsically conducting coating for corrosion protection of structural steels.

    Science.gov (United States)

    Pan, Tongyan; Wang, Zhaoyang

    2013-11-01

    Among the various corrosion protection strategies for structural steels, coating techniques provide the most cost-effective protection and have been used as the primary mode of corrosion protection. Existing coating techniques however have been used mainly for their barrier capability and therefore all have a limited service life due to oxidation aging, electrolytic degradation, or various inadvertent defects and flaws occurred in and after coating applications. This work investigated the anti-corrosion potential of a π-conjugated polymer-polyaniline (PANi), which was doped into an intrinsically conducting polymer and then included in a two-layer coating system as a primer layer. To achieve a long service life, the primer layer was made by mixing the conductive PANi in a waterborne poly-vinyl butyral solution to provide strong adhesion to steel surface, and then topcoated with a layer of elastomer-modified polyethylene to obtain extra mechanical and barrier protections. Two ASTM standard tests were conducted to evaluate the corrosion durability and tensile adhesion of the two-layer system, in which the system demonstrated superior performance. The Scanning Kelvin Probe Force Microscopy (SKPFM) was used to provide the microscopic evidences for the outstanding performance. Copyright © 2013 Wiley Periodicals, Inc.

  5. Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

    DEFF Research Database (Denmark)

    Leisner, P.; Benzon, M. E.; Christoffersen, Lasse

    1996-01-01

    Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...

  6. Chitosan coatings crosslinked with genipin for corrosion protection of AZ31 magnesium alloy sheets.

    Science.gov (United States)

    de Y Pozzo, Ludmila; da Conceição, Thiago F; Spinelli, Almir; Scharnagl, Nico; Pires, Alfredo T N

    2018-02-01

    In this study, coatings of chitosan crosslinked with genipin were prepared on sheets of AZ31 magnesium alloy and their corrosion protection properties were characterized by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The coatings were also characterized by means of FTIR and XPS. It was observed that the crosslinking process decreases the corrosion current and shifts the corrosion potential of the alloy to less negative values. The EIS analysis demonstrated that the crosslinking process increases the maximum impedance after short and long exposure times. The superior performance of the crosslinked coatings is related to a lower degree of swelling, as observed in the swelling tests carried out on free-standing films. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Electrochemical Behavior of Bilayer Thermal-Spray Coatings in Low-Temperature Corrosion Protection

    Directory of Open Access Journals (Sweden)

    Esmaeil Sadeghimeresht

    2017-09-01

    Full Text Available Cr3C2-NiCr coatings are greatly used to protect critical components in corrosive environments and to extend their lifetime and/or improve functional performance. However, the pores formed during spraying restrict the coating’s applicability area for many corrosion protection applications. To overcome this technical challenge, bilayer coatings have been developed, in which an additional layer (the so-called “intermediate layer” is deposited on the substrate before spraying the Cr3C2-NiCr coating (the so-called “top layer”. The corrosion behavior of the bilayer coating depends on the composition and microstructure of each layer. In the present work, different single-layer coatings (i.e., Cr3C2-NiCr, Fe- and Ni-based coatings were initially sprayed by a high-velocity air fuel (HVAF process. Microstructure analysis, as well as electrochemical tests, for example, open-circuit potential (OCP and polarization tests, were performed. The potential difference (ΔE had a great influence on galvanic corrosion between the top and intermediate layers, and thus, the coatings were ranked based on the OCP values (from high to low as follows: NiCoCrAlY > NiCr > Cr3C2-NiCr > NiAl > Fe-based coatings (alloyed with Cr > pure Ni. The Ni-based coatings were chosen to be further used as intermediate layers with the Cr3C2-NiCr top layer due to their capabilities to show high OCP. The corrosion resistance (Rp of the bilayer coatings was ranked (from high to low as follows: NiCoCrAlY/Cr3C2-NiCr > NiCr/Cr3C2-NiCr > NiAl/Cr3C2-NiCr > Ni/Cr3C2-NiCr. It was shown that splat boundaries and interconnected pores are detrimental for corrosion resistance, however, a sufficient reservoir of protective scale-forming elements (such as Cr or/and Al in the intermediate layer can significantly improve the corrosion resistance.

  8. The Impact of Microbiologically Influenced Corrosion on Protective Polymer Coatings

    National Research Council Canada - National Science Library

    Mansfield, F

    1998-01-01

    ...) as well as visual observations. Statistical analyses have been performed to determine the effects of coating composition on coating performance in general and attack by microorganisms in particular...

  9. Characterization of a “Smart” Hybrid Varnish Electrospun Nylon Benzotriazole Copper Corrosion Protection Coating

    Directory of Open Access Journals (Sweden)

    C. Menchaca

    2012-01-01

    Full Text Available This work presents the electrochemical evaluation of a proposed copper corrosion protection hybrid coating acting as a smart corrosion protection system. This consists of an alkyd varnish, painted over electrospun nylon fibers acting as a secondary diffusion barrier and also as a benzotriazole (BTAH inhibitor nanocontainer. Submicron diameter electrospun nylon 6-6 fiber nanocontainers were prepared from a polymeric solution containing BTAH at different concentrations, and Cu samples were coated with the electrospun fibers and painted over with an alkyd varnish by the drop method. Functional groups in fibers were determined through FTIR spectroscopy. Optical and SEM microscopies were used to characterize the nanocontainer fibers. Samples were evaluated using electrochemical impedance and noise, during six weeks of immersion, in a chloride-ammonium sulfate solution. Excellent response was obtained for the smart inhibitor coating system. For long periods of immersion good corrosion protection performance was observed. The results presented demonstrate the good barrier properties of the hybrid coating, obstructing the diffusion of aggressive species, through the electrospun structure. Furthermore the nanocontainer functionality to store and liberate the corrosion inhibitor, only when it is needed, was also proved.

  10. Self Healing Ultrahydrophobic Coatings for Corrosion Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The total annual corrosion related costs in the US has been estimated at greater than $300 billion. Much of these costs are associated with scraping and repainting...

  11. Smart Coatings for Launch Site Corrosion Protection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Corrosion is a serious problem that has enormous costs for the nation (4.2% GDP in 2007) and worldwide. Kennedy Space Center is located in one of the most naturally...

  12. THE USE OF COATINGS FOR HOT CORROSION AND EROSION PROTECTION IN TURBINE HOT SECTION COMPONENTS

    Directory of Open Access Journals (Sweden)

    Hayrettin AHLATCI

    1999-01-01

    Full Text Available High pressure turbine components are subjected to a wide variety of thermal and mechanical loading during service. In addition, the components are exposed to a highly oxidizing atmosphere which may contain contaminants such as sulphates, chlorides and sulphuorous gases along with erosive media. So the variety of surface coatings and deposition processes available for the protection of blade and vane components in gas turbines are summarised in this study. Coating types range from simple diffusion aluminides to modified aluminides and a CoCrAlY overlayer. The recommendations for corrosion-resistant coatings (for low temperature and high temperature hot corrosion environments are as follows: silicon aluminide and platinumchromium aluminide for different gas turbine section superalloys substrates. Platinum metal additions are used to improve the properties of coatings on turbine components. Inorganic coatings based on ceramic films which contain aluminium or aluminium and silicon are very effective in engines and gas turbines. Diffusion, overlayer and thermal barrier coatings which are deposited on superalloys gas turbine components by pack cementation, plasma spraying processes and a number of chemical vapour deposition, physical vapour deposition processes (such as electron beam, sputtering, ion plating are described. The principles underlying the development of protective coatings serve as a useful guide in the choice of coatings for other high temperature applications.

  13. Routes to extrinsic and intrinsic self-healing corrosion protective sol-gel coatings: a review

    Science.gov (United States)

    Abdolah Zadeh, M.; van der Zwaag, S.; Garcia, S. J.

    2013-06-01

    Sol-gel pre-treatments and coatings are an important class of passive protective coatings, which can effectively prevent corrosion of various metallic substrates through adhesion improvement and barrier protection. Recently, sol-gel chemistry has been proposed as an appropriate method for implementation of self-healing functionality in coatings via extrinsic concepts. In this review we will analyze the most relevant existing works on self-healing sol-gel coatings, including new work done in the direction of implementing intrinsic healing capabilities to sol-gels. The development of active sol-gel coatings is due to the broad chemical versatility of precursors and low processing temperature of this type of chemistry.

  14. Corrosion inhibiting organic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  15. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  16. Coated silicon comprising material for protection against environmental corrosion

    Science.gov (United States)

    Hazel, Brian Thomas (Inventor)

    2009-01-01

    In accordance with an embodiment of the invention, an article is disclosed. The article comprises a gas turbine engine component substrate comprising a silicon material; and an environmental barrier coating overlying the substrate, wherein the environmental barrier coating comprises cerium oxide, and the cerium oxide reduces formation of silicate glass on the substrate upon exposure to corrodant sulfates.

  17. POLYPHENYLENESULFIED/MONTOMORILLONITE CLAY NANOCOMPOSITE COATINGS: THEIR EFFICACY IN PROTECTING STEEL AGAINST CORROSION.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA, T.; GAWLIK, K.

    2006-06-01

    Nanoscale montomorillonite (MMT) clay fillers became dispersed in a polyphenylenesulfied (PPS) matrix through the processes of octadecylamine (ODA) intercalation {yields} molten PPS co-intercalation {yields} exfoliation. Cooling this molten exfoliated material led to the formation of a PPS/MMT nanocomposite. The MMT nanofiller conferred three advanced properties on the semi-crystalline PPS: First, it raised its melting point by nearly 40 C to 290 C; second, it increased its crystallization energy, implying that an excellent adherence of the nanofillers surfaces to PPS in terms of a good interfacial bond; and, third, it abated the degree of its hydrothermal oxidation due to sulfide {yields} sulfite linkage transformations. When this advanced PPS nanocomposite was used as a corrosion-preventing coating for carbon steel in a simulated geothermal environment at 300 C, a coating of {approx}150 {micro}m thickness adequately protected the steel against hot brine-caused corrosion. In contrast, an MMT-free PPS coating of similar thickness was not nearly as effective in mitigating corrosion as was the nanocompsite; in fact, the uptake of corrosive ionic electrolyte by the unmodified coating increased with an extending exposure time.

  18. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    Science.gov (United States)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  19. Phytic acid doped polyaniline containing epoxy coatings for corrosion protection of Q235 carbon steel

    Science.gov (United States)

    Hao, Yongsheng; Sani, Luqman Abdullahi; Ge, Tiejun; Fang, Qinghong

    2017-10-01

    Corrosion protection of epoxy coatings contained with phytic acid-doped polyaniline (PANI-PA) for Q235 carbon steel was studied in this work. Synthesized PANI-PA particles were characterized by XPS, TGA, and FTIR, respectively. The coating performance was investigated by OCP, EIS, and SVET, respectively. The experimental results show that the concentration of PANI-PA has a significant influence to the barrier effect of the epoxy coating. Epoxy coating loaded with 2 wt.% PANI-PA has the best protection ability and self-healing function to a certain degree. The self-healing function of PANI-PA is attributed to the synergistic effect of the passivation of PANI and the chelation of the dedoped phytic acid ions with iron ions. Therefore, PANI-PA can be used as an effective anticorrosion pigment in future.

  20. Development of self-healing coatings for corrosion protection on metallic structures

    OpenAIRE

    Stankiewicz, Alicja.; Barker, Michael B.

    2016-01-01

    Inspired by biological systems, artificial self-healing materials are designed for repairing local damage caused by external factors. The rapidly expanding field of self-healing systems contains, among others, materials with well-defined surface properties. Undoubtedly, enhancing surface functionalisation, by applying smart coatings, enjoys an extensive interest. The self-healing ability is particularly essential property for corrosion protection strategies, especially when the use of one of ...

  1. The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V. [Boston Univ., MA (United States)

    1998-05-01

    Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

  2. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  3. Electrochemical Study of Polymer and Ceramic-Based Nanocomposite Coatings for Corrosion Protection of Cast Iron Pipeline

    Directory of Open Access Journals (Sweden)

    Ameen Uddin Ammar

    2018-02-01

    Full Text Available Coating is one of the most effective measures to protect metallic materials from corrosion. Various types of coatings such as metallic, ceramic and polymer coatings have been investigated in a quest to find durable coatings to resist electrochemical decay of metals in industrial applications. Many polymeric composite coatings have proved to be resistant against aggressive environments. Two major applications of ferrous materials are in marine environments and in the oil and gas industry. Knowing the corroding behavior of ferrous-based materials during exposure to these aggressive applications, an effort has been made to protect the material by using polymeric and ceramic-based coatings reinforced with nano materials. Uncoated and coated cast iron pipeline material was investigated during corrosion resistance by employing EIS (electrochemical impedance spectroscopy and electrochemical DC corrosion testing using the “three electrode system”. Cast iron pipeline samples were coated with Polyvinyl Alcohol/Polyaniline/FLG (Few Layers Graphene and TiO2/GO (graphene oxide nanocomposite by dip-coating. The EIS data indicated better capacitance and higher impedance values for coated samples compared with the bare metal, depicting enhanced corrosion resistance against seawater and “produce water” of a crude oil sample from a local oil rig; Tafel scans confirmed a significant decrease in corrosion rate of coated samples.

  4. Electrochemical Study of Polymer and Ceramic-Based Nanocomposite Coatings for Corrosion Protection of Cast Iron Pipeline.

    Science.gov (United States)

    Ammar, Ameen Uddin; Shahid, Muhammad; Ahmed, Muhammad Khitab; Khan, Munawar; Khalid, Amir; Khan, Zulfiqar Ahmad

    2018-02-25

    Coating is one of the most effective measures to protect metallic materials from corrosion. Various types of coatings such as metallic, ceramic and polymer coatings have been investigated in a quest to find durable coatings to resist electrochemical decay of metals in industrial applications. Many polymeric composite coatings have proved to be resistant against aggressive environments. Two major applications of ferrous materials are in marine environments and in the oil and gas industry. Knowing the corroding behavior of ferrous-based materials during exposure to these aggressive applications, an effort has been made to protect the material by using polymeric and ceramic-based coatings reinforced with nano materials. Uncoated and coated cast iron pipeline material was investigated during corrosion resistance by employing EIS (electrochemical impedance spectroscopy) and electrochemical DC corrosion testing using the "three electrode system". Cast iron pipeline samples were coated with Polyvinyl Alcohol/Polyaniline/FLG (Few Layers Graphene) and TiO₂/GO (graphene oxide) nanocomposite by dip-coating. The EIS data indicated better capacitance and higher impedance values for coated samples compared with the bare metal, depicting enhanced corrosion resistance against seawater and "produce water" of a crude oil sample from a local oil rig; Tafel scans confirmed a significant decrease in corrosion rate of coated samples.

  5. Corrosion protection performance of waterborne epoxy coatings containing self-doped polyaniline nanofiber

    Science.gov (United States)

    Qiu, Shihui; Chen, Cheng; Cui, Mingjun; Li, Wei; Zhao, Haichao; Wang, Liping

    2017-06-01

    Self-doped sulfonated polyaniline (SPANi) nanofiber was synthesized by the copolymerization of 2-aminobenzenesulfonic acid (ASA) and aniline via a rapid mixing polymerization approach. The chemical structure of SPANi was investigated by the Fourier-transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), UV-vis spectra and X-ray diffraction (XRD) pattern. The as-prepared SPANi nanofibers had 45 nm average diameter and length up to 750 nm as measured by scanning electron microscope (SEM) and transmission electron microscope (TEM). The self-doped SPANi nanofiber possessed excellent aqueous solubility, good conductivity (0.11 S/cm) and reversible redox activity, making it suitable as a corrosion inhibitor for waterborne coatings. The prepared SPANi/waterborne epoxy composite coatings exhibited remarkably improved corrosion protection compared with pure waterborne epoxy coating as proved by the polarization curves and electrochemical impedance spectroscopy (EIS). The passivation effect of SPANi nanofiber and the corrosion products beneath the epoxy coatings immersed in 3.5% NaCl solution as a function of time were also investigated in this study.

  6. Ceramic coatings of LA141 alloy formed by plasma electrolytic oxidation for corrosion protection.

    Science.gov (United States)

    Li, Zhijun; Yuan, Yi; Sun, Pengpeng; Jing, Xiaoyan

    2011-09-01

    Superlight Mg-Li alloy is a promising structural materials in aerospace, automobile, and electronics because of its excellent properties such as low density, high ductility, superior strength-to-weight ratio, and good damping ability. The fabrication of compact plasma electrolytic oxidation coatings with excellent corrosion resistance is valuable for the widespread application of Mg-Li alloy. Here we present a ceramic coating on the surface of Mg-14Li-1Al (LA141) alloy for corrosion protection via plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte with tungstate as an additive. X-ray photoelectron spectroscopy and thin film-X-ray diffraction analysis of coatings show that the surface coating is mainly comprised of Mg(2)SiO(4), MgO and WO(3). Scanning electron microscopy observations have revealed that the dense and compact coating formed in the presence of tungstate has less structural imperfections in comparison to the control one fabricated without use of tungstate. The effect of oxidation time on the morphology and phase composition of coatings is also examined in detail.

  7. Development of self-healing coatings for corrosion protection on metallic structures

    Science.gov (United States)

    Stankiewicz, Alicja; Barker, Michael B.

    2016-08-01

    Inspired by biological systems, artificial self-healing materials are designed for repairing local damage caused by external factors. The rapidly expanding field of self-healing systems contains, among others, materials with well-defined surface properties. Undoubtedly, enhancing surface functionalisation, by applying smart coatings, enjoys an extensive interest. The self-healing ability is particularly essential property for corrosion protection strategies, especially when the use of one of the most effective corrosion systems, based on chromium(VI) compounds, is now banned by the current registration, evaluation, authorisation and restriction of chemicals legislation. Self-healing protective coatings are produced using macromolecular compounds, ceramics, metals and composites. Considering the wide range of available materials, the number of potential combinations seems to be unlimited. The self-healing action of such coatings is activated by appropriate stimuli: temperature changes, radiation, pH changes, pressure changes and mechanical action. In this paper, the research and practical implications of the various approaches to achieving self-healing functionality of protective coatings, as well as potential developments in this area, are explored.

  8. Electrochemical synthesis of polypyrrole-Al2O3 composite coating on 316 stainless steel for corrosion protection

    Science.gov (United States)

    Yan, Qun; Li, Chuanxian; Huang, Tingting; Yang, Fei

    2017-03-01

    Polypyrrole (PPy)-Al2O3 composite coating was electrochemically deposited on 316 stainless steel (316 SS) by cyclic voltammetry technique. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were employed to understand the morphology and composition of the PPy-Al2O3 coated SS. The corrosion protection ability of the PPy-Al2O3 coating was studied using open circuit potential (Eocp)-time measurements, polarization curves, and electrochemical impedance spectroscopy (EIS) after the electrodes had been immersed in a 3.5 wt% NaCl solution as the corrosive media. The results showed that PPy-Al2O3 composite coatings have a homogeneous and smooth surface without detectable cracks. Anodic polarization analysis revealed that the hybrid films provided an exceptional barrier and corrosion protection in comparison with PPy coating. The EIS studies indicated that the charge transfer resistance increases with the presence of PPy-Al2O3. PPy-Al2O3 composite coating provides better corrosion protection and can be considered as a coating material to protect 316SS. With increase in Al2O3/Py mole ratio, PPy-Al2O3 coatings tend to exhibit a better corrosion resistance ability.

  9. Electrodeposition and Characterization of Mn-Cu-Zn Alloys for Corrosion Protection Coating

    Science.gov (United States)

    Tsurtsumia, Gigla; Gogoli, David; Koiava, Nana; Kakhniashvili, Izolda; Jokhadze, Nunu; Lezhava, Tinatin; Nioradze, Nikoloz; Tatishvili, Dimitri

    2017-12-01

    Mn-Cu-Zn alloys were electrodeposited from sulphate bath, containing citrate or EDTA and their mixtures as complexing ligands. The influence of bath composition and deposition parameters on alloys composition, cathodic current efficiency and structural and electrochemical properties were studied. At a higher current density (≥ 37.5 A dm-2) a uniform surface deposit of Mn-Cu-Zn was obtained. Optimal pH of electrolyte (0.3 mol/dm3Mn2+ + 0.6 mol/dm3 (NH4)2SO4 +0.1 mol/dm3Zn2++0.005 mol/dm3 Cu2++ 0.05mol/dm3Na3Cit + 0.15mol/dm3 EDTA; t=300C; τ=20 min) for silvery, nonporous coating of Mn-Cu-Zn alloy was within 6.5-7.5; coating composition: 71-83% Mn, 6-7.8% Cu, 11.5-20% Zn, current efficiency up to 40%. XRD patterns revealed BCT (body centred tetragonal) γ-Mn solid phase solution (lattice constants a=2.68 Å c=3.59 Å). Corrosion measurements of deposited alloys were performed in aerated 3.5% NaCl solution. The corrosion current density (icorr) of the electrodeposited alloys on carbon steel was 10 times lower than corrosion rate of pure zinc and manganese coatings. Triple alloy coatings corrosion potential (Ecorr = -1140 mV vs. Ag/AgCl) preserved negative potential value longer (more than three months) compared to carbon steel substrate (Ecorr = -670 mV vs. Ag/AgCl). Tafel polarization curves taken on Mn-Cu-Zn alloy coating in aerated 3.5% NaCl solution did not show a typical passivation behaviour which can be explained by formation oflow solubility of adherent corrosion products on the alloy surface. Corrosion test of Mn-Cu-Zn electrocoating in chlorine environment shows that it is the best cathodic protective coating for a steel product.

  10. Atomic Layer Deposited Coatings on Nanowires for High Temperature Water Corrosion Protection.

    Science.gov (United States)

    Yersak, Alexander S; Lewis, Ryan J; Liew, Li-Anne; Wen, Rongfu; Yang, Ronggui; Lee, Yung-Cheng

    2016-11-30

    Two-phase liquid-cooling technologies incorporating micro/nanostructured copper or silicon surfaces have been established as a promising thermal management solution to keep up with the increasing power demands of high power electronics. However, the reliability of nanometer-scale features of copper and silicon in these devices has not been well investigated. In this work, accelerated corrosion testing reveals that copper nanowires are not immune to corrosion in deaerated pure hot water. To solve this problem, we investigate atomic layer deposition (ALD) TiO 2 coatings grown at 150 and 175 °C. We measured no difference in coating thickness for a duration of 12 days. Using a core/shell approach, we grow ALD TiO 2 /Al 2 O 3 protective coatings on copper nanowires and demonstrate a preservation of nanoengineered copper features. These studies have identified a critical reliability problem of nanoscale copper and silicon surfaces in deaerated, pure, hot water and have successfully demonstrated a reliable solution using ALD TiO 2 /Al 2 O 3 protective coatings.

  11. Plasma Sprayed Bondable Stainless Surface (BOSS) Coatings for Corrosion Protection and Adhesion Treatments

    Science.gov (United States)

    Davis, G. D.; Groff, G. B.; Rooney, M.; Cooke, A. V.; Boothe, R.

    1995-01-01

    Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.

  12. Effective corrosion protection of AA6061 aluminum alloy by sputtered Al-Ce coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Crespo, M.A., E-mail: mdominguezc@ipn.m [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Torres-Huerta, A.M. [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Rodil, S.E. [Instituto de Investigacion en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, Ciudad Universitaria, Del. Coyoacan, C.P. 04510 Mexico, D.F. (Mexico); Ramirez-Meneses, E. [Instituto Politecnico Nacional, GIPMAT CICATA-Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Suarez-Velazquez, G.G. [Alumna del PTA del CICATA-Altamira IPN, km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Hernandez-Perez, M.A. [Instituto Politecnico Nacional, ESIQIE, C.P. 07738 Mexico, D.F. (Mexico)

    2009-12-30

    Al-Ce coatings were deposited on silicon and AA6061 aluminum alloy substrates by DC magnetron sputtering using aluminum in combination with pure cerium targets. The materials were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and electrochemical impedance spectroscopy (EIS) in order to consider their application as high corrosion resistance coatings. The corrosion behavior of the films was studied using a NaCl aqueous solution (3.5 wt%). As for the characterization results, an apparent amorphous phase of aluminum oxide with small cerium compounds embedded in the matrix was detected by the X-ray diffraction patterns and HRTEM on the deposited films at 200 W and 4 Pa. At these conditions, AFM and SEM images evidenced crack-free coatings with low-roughness nanometric structures and columnar growth. EIS and Tafel results converged to indicate an inhibition of the corrosion reactions. The film displayed good stability in the aggressive medium and after 1 day of exposure underwent very little degradation. The variations in the impedance and Tafel characteristics were found to occur as a function of cerium content, which provokes important changes in the film protective properties.

  13. Corrosion protection of Sunselect, a spectrally selective solar absorber coating, by (3-mercaptopropyl)trimethoxysilane

    Energy Technology Data Exchange (ETDEWEB)

    Kozelj, Matjaz; Vuk, Angela Surca; Jerman, Ivan; Orel, Boris [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)

    2009-10-15

    The formation of a protective layer from (3-mercaptopropyl)trimethoxysilane (MPTMS) on commercial Sunselect, cermet-based spectrally selective coating (Alanod, DE), was studied by non-electrochemical (infrared reflection-absorption - IR RA, X-ray photoelectron spectroscopy - XPS), electrochemical (cyclic voltammetry (CV) in the presence of a redox probe (Cd{sup +2}), and potentiodynamic (PD)) techniques. By simple immersion and subsequent dip coating of the Sunselect substrate in the MPTMS sol, the hydrolyzed MPTMS precursor was adsorbed on the substrate, forming a protective layer imparting corrosion stability to Sunselect in a salt spray chamber for at least 20 days, outperforming any other sol-gel coating used so far for the corrosion protection of Sunselect. This was attributed to the penetration of MPTMS into the porous cermet structure through the upper antireflective Sn-oxide layer, as shown from XPS depth profile. Detailed analysis of the hydrolysis and condensation reactions of the MPTMS precursor by {sup 29}Si NMR and IR spectroscopic techniques is reported. The most important finding was the observation that the applied MPTMS layer did not affect the spectral selectivity, as inferred from the solar absorptance increase of 1% and thermal emittance increase of not more than 2%. (author)

  14. Parameters governing the corrosion protection efficiency of fusion-bonded epoxy coatings on reinforcing steel.

    Science.gov (United States)

    2008-01-01

    The purpose of this study was to investigate various epoxy coating and exposure parameters to determine their effects on the corrosion of reinforcing steel. The parameters investigated were: chloride content at the bar depth, coated bar corroded area...

  15. Corrosion Protection Properties and Mechanism of Epoxy/Acetic Acid-Doped Polyaniline Coating on Magnesium Alloy.

    Science.gov (United States)

    Jin, Tao; Wang, Yanmin; Yin, Hong; Hao, Xiaojuan

    2018-07-01

    Poly(amidoamine)(PAMAM)/epoxy/acetic acid-doped polyaniline (PAni) coatings were successfully prepared and coated on magnesium alloy substrates. X-ray diffraction pattern, Fourier transform infrared spectroscopy, scanning electron microscopy technique were used to characterize the composition and morphology of acetic acid-doped PAni and composite coatings. The effect of the usage amount of doped PAni on the corrosion protection performance was evaluated with electrochemical measurement in 3.5 wt.% NaCl solutions. Tafel and electrochemical impedance spectroscopy analysis revealed that the addition of 1.0 wt.% doped PAni provided the superior corrosion protection properties. The corrosion protection mechanism was investigated by using electron probe microanalysis test and theoretical physical model. The doped PAni could obviously shrink the pits and made epoxy resin matrix denser by cross-linking and hydrogen bonding. The composite coatings exhibited better corrosion protection properties compared to pure epoxy coating. The in situ generated corrosion products provided anodic corrosion inhibition due to the easier penetration of acetate ions, and better physical barrier mechanism was promoted by the addition of doped PAni.

  16. Robust Slippery Coating with Superior Corrosion Resistance and Anti-Icing Performance for AZ31B Mg Alloy Protection.

    Science.gov (United States)

    Zhang, Jialei; Gu, Changdong; Tu, Jiangping

    2017-03-29

    Biomimetic slippery liquid-infused porous surfaces (SLIPSs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and susceptibility to frosting. Herein, we fabricated a double-layered SLIPS coating on the AZ31 Mg alloy for corrosion protection and anti-icing application. The porous top layer was infused by lubricant, and the compact underlayer was utilized as a corrosion barrier. The water-repellent SLIPS coating exhibits a small sliding angle and durable corrosion resistance compared with the SHS coating. Moreover, the SLIPS coating delivers durable anti-icing performance for the Mg alloy substrate, which is obviously superior to the SHS coating. Multiple barriers in the SLIPS coating, including the infused water-repellent lubricant, the self-assembled monolayers coated porous top layer, and the compact layered double hydroxide-carbonate composite underlayer, are suggested as being responsible for the enhanced corrosion resistance and anti-icing performance. The robust double-layered SLIPS coating should be of great importance to expanding the potential applications of light metals and their alloys.

  17. Effect of chelating agent acetylacetone on corrosion protection properties of silane-zirconium sol–gel coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mei, E-mail: yumei@buaa.edu.cn; Liang, Min; Liu, Jianhua; Li, Songmei; Xue, Bing; Zhao, Hao

    2016-02-15

    Graphical abstract: - Highlights: • AcAc was employed as a chelating agent in order to form stable sols. • The sol particle size depends on the concentration of AcAc. • AFM results indicate that AcAc content affects the morphology of the coatings. • Coating AcAc3 shows the optimal corrosion protection. - Abstract: The hybrid sol–gel coatings on AA2024-T3 were prepared with a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) and a metal alkoxide tetra-n-propoxyzirconium (TPOZ) as precursors. The effect of acetylacetone (AcAc) as a chelating agent on the corrosion protection properties of sol–gel coatings were evaluated and the optimal AcAc/TPOZ molar ratio was obtained. The sol–gel coatings were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The corrosion protection properties of the coatings were evaluated by means of potentiodynamic polarization study (PDS) and electrochemical impedance spectroscopy (EIS). It is demonstrated that AcAc avoids fast hydrolysis of TPOZ and benefits to form stable sols. The coating with AcAc/TPOZ molar ratio of 3 shows the best corrosion protection performance in 0.05 M NaCl solution.

  18. Corrosion protection of SiC-based ceramics with CVD mullite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.L.; Sarin, V.K. [Boston Univ., MA (United States). Dept. of Mfg. Engineering

    1997-12-01

    For the first time, crystalline mullite coatings have been chemically vapor deposited on SiC substrates to enhance its corrosion and oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments.

  19. The role of surface preparation in corrosion protection of copper with nanometer-thick ALD alumina coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mirhashemihaghighi, Shadi; Światowska, Jolanta [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Maurice, Vincent, E-mail: vincent.maurice@chimie-paristech.fr [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Seyeux, Antoine; Klein, Lorena H. [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France); Salmi, Emma; Ritala, Mikko [Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Marcus, Philippe [PSL Research University, CNRS – Chimie ParisTech, Institut de Recherche de Chimie Paris (IRCP), 11 rue Pierre et Marie Curie, 75005 Paris (France)

    2016-11-30

    Highlights: • 10–50 nm thick alumina coatings were grown on copper by atomic layer deposition. • Surface smoothening by substrate annealing was studied as pre-deposition treatment. • Corrosion protection is promoted by pre-treatment for 10 nm but not for thicker films. • Local adhesion failure is assigned to the stresses accumulated in the thicker films. • Surface smoothening decreases the interfacial strength bearing the film stresses. - Abstract: Surface smoothening by substrate annealing was studied as a pre-treatment for improving the corrosion protection provided to copper by 10, 20 and 50 nm thick alumina coatings deposited by atomic layer deposition. The interplay between substrate surface state and deposited film thickness for controlling the corrosion protection provided by ultrathin barrier films is demonstrated. Pre-annealing at 750 °C heals out the dispersed surface heterogeneities left by electropolishing and reduces the surface roughness to less than 2 nm independently of the deposited film thickness. For 10 nm coatings, substrate surface smoothening promotes the corrosion resistance. However, for 20 and 50 nm coatings, it is detrimental to the corrosion protection due to local detachment of the deposited films. The weaker adherence of the thicker coatings is assigned to the stresses accumulated in the films with increasing deposited thickness. Healing out the local heterogeneities on the substrate surface diminishes the interfacial strength that is bearing the stresses of the deposited films, thereby increasing adhesion failure for the thicker films. Pitting corrosion occurs at the local sites of adhesion failure. Intergranular corrosion occurs at the initially well coated substrate grain boundaries because of the growth of a more defective and permeable coating at grain boundaries.

  20. In-situ AFM and EIS study of a solventborne alkyd coating with nanoclay for corrosion protection of carbon steel

    OpenAIRE

    Jing, Li; Ecco, Luiz; Fedel, Michele; Ermini, Valentina; Delmas, Gregory; Pan, Jinshan

    2015-01-01

    A solventborne alkyd composite coating containing modified montmorillonite (MMT) nanoclay was made on carbon steel, and its corrosion protection was investigated by in-situ atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) measurements in 3 wt.% NaCl solution. X-ray diffraction (XRD) analysis indicated intercalation of the MMT sheets in the composite coating. Thermo-gravimetric analysis (TGA) demonstrated improved thermal stability of the composite coating due to ...

  1. Corrosion protection and improved cytocompatibility of biodegradable polymeric layer-by-layer coatings on AZ31 magnesium alloys.

    Science.gov (United States)

    Ostrowski, Nicole; Lee, Boeun; Enick, Nathan; Carlson, Benjamin; Kunjukunju, Sangeetha; Roy, Abhijit; Kumta, Prashant N

    2013-11-01

    Composite coatings of electrostatically assembled layer-by-layer anionic and cationic polymers combined with an Mg(OH)2 surface treatment serve to provide a protective coating on AZ31 magnesium alloy substrates. These ceramic conversion coating and layer-by-layer polymeric coating combinations reduced the initial and long-term corrosion progression of the AZ31 alloy. X-ray diffraction and Fourier transform infrared spectroscopy confirmed the successful application of coatings. Potentiostatic polarization tests indicate improved initial corrosion resistance. Hydrogen evolution measurements over a 2 week period and magnesium ion levels over a 1 week period indicate longer range corrosion protection and retention of the Mg(OH)2 passivation layer in comparison to the uncoated substrates. Live/dead staining and DNA quantification were used as measures of biocompatibility and proliferation while actin staining and scanning electron microscopy were used to observe the cellular morphology and integration with the coated substrates. The coatings simultaneously provided improved biocompatibility, cellular adhesion and proliferation in comparison to the uncoated alloy surface utilizing both murine pre-osteoblast MC3T3 cells and human mesenchymal stem cells. The implementation of such coatings on magnesium alloy implants could serve to improve the corrosion resistance and cellular integration of these implants with the native tissue while delivering vital drugs or biological elements to the site of implantation. Copyright © 2013. Published by Elsevier Ltd.

  2. Use of cerium-based inhibitors in electrochemically deposited coatings for the corrosion protection of aluminum alloys

    Science.gov (United States)

    Morris, Eric Leon

    2000-10-01

    Corrosion is a common problem in military aircraft and structural components made from high strength aluminum alloys such as 7075 T-6 and 2024 T-3 are particularly susceptible. Chromating is the most commercially used surface pre-treatment for the corrosion protection of aluminum alloys in the aircraft and the aerospace industries. Major reasons for the widespread use of chromium-based protective coatings are their self-healing nature, excellent corrosion resistance and their ease of application. However, current environmental legislation is moving towards total exclusion of hexavalent chromium, Cr6+ due to its toxic nature. Regulatory pressure to reduce the hazardous waste of chromium supports development of non-toxic alternative methods of corrosion protection. The degree and type of corrosion protection provided by these alternative coatings are also of importance. ASTM standards are used to evaluate coating performance, but these methods are time consuming and not particularly quantitative nor reproducible. Some ASTM methods require from 336 to 2000 hours, so it is clear that the development of an accelerated test method for the evaluation of new corrosion inhibitive systems which successfully correlates with the ASTM B-117 Salt Spray test is necessary. The purpose of this study was the incorporation and evaluation of promising cerium-based corrosion inhibitors into cathodically deposited electrocoat primers for the replacement of toxic chromium in military and aerospace applications. Classical ASTM methods, as well as short term electrochemical tests, were used to evaluate the corrosion protection provided by the inhibitor containing primer formulations. SEM/EDX and Auger spectroscopies were used to characterize the morphology and elemental composition of the resulting coatings.

  3. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

    Science.gov (United States)

    Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

    2011-06-01

    Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

  4. Fabrication of multifunctional CaP-TC composite coatings and the corrosion protection they provide for magnesium alloys.

    Science.gov (United States)

    Tan, Cui; Zhang, Xiaoxu; Li, Qing

    2017-08-28

    Two major problems with magnesium (Mg) alloy biomaterials are the poor corrosion resistance and infection associated with implantation. In this study, a novel calcium phosphate (CaP)/tetracycline (TC) composite coating for Mg implants that can both improve the corrosion resistance of Mg and release a drug in a durable way is reported. Scanning electron microscope (SEM) images showed that TC additives make the CaP coating more compact and uniform. Electrochemical tests indicated CaP/TC coatings can provide excellent corrosion protection for Mg alloy substrates. Besides, TC additives can also provide effective prevention of bone infection and inflammation due to its broad-spectrum antibacterial properties. The one-step hydrothermal process reported here greatly simplified the multi-step fabrication of smart coatings reported previously.

  5. Electrophoretic deposition of hybrid coatings on aluminum alloy by combining 3-aminopropyltrimethoxysilan to silicon–zirconium sol solutions for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mei; Xue, Bing; Liu, Jianhua, E-mail: yumei@buaa.edu.cn; Li, Songmei; Zhang, You

    2015-09-01

    Electrophoretic deposition (EPD) silicon–zirconium organic–inorganic hybrid coatings were applied on LC4 aluminum alloy for corrosion protection. 3-Glycidoxypropyl-trimethoxysilane (GTMS) and Zirconium (IV) n-propoxide (TPOZ) were used as precursors. 3-Aminopropyl-trimethoxysilane (APS) was added to enhance the corrosion protective performance of the coatings. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize morphology, microstructure and component. The results show that the addition of APS leads to the enhanced migration and deposition of positively charged colloidal particles on the surface of metal substrate, which results in the thickness increasing of coatings. However, loading an excessive amount of APS gives a heterogeneous coating surface. The corrosion protective performance of coatings were measured by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results indicate that the addition of APS improves corrosion protective performance of coatings. The optimal addition content of APS is about 15%. The 15% APS coating is uniform and dense, as well as has good corrosion protective performance. The impedance value (1.58 × 10{sup 5} Ω·cm{sup 2}, at the lowest frequency) of 15% APS coating is half order of magnitude higher than that of coating without APS, and 15% APS coating always keeps the best corrosion protective performance with prolonged immersion time. This kind of coating is identified with “double-structure” properties based on the analysis of EIS and potentiodynamic polarization. Furthermore, the equivalent circuit results indicate that the intermediate oxide layer plays a main role in corrosion protection. - Highlights: • Electrophoretic deposition hybrid coatings are prepared on LC4 aluminum alloy. • 3-Aminopropyl-trimethoxysilane (APS) enhances the corrosion protective performance. • The

  6. Long-Term Corrosion Protection of a Cupro-Nickel Alloy Due to Graphene Coating

    Directory of Open Access Journals (Sweden)

    Abhishek Tiwari

    2017-11-01

    Full Text Available This study demonstrates the corrosion resistance of a Cu-Ni alloy coated with a multi-layer graphene. This is one of the first demonstrations of long-term corrosion resistance due to graphene coating, which is crucial since earlier studies have suggested graphene-coated copper to be considerably inferior to bare copper in terms of corrosion during long-term exposure to a corrosive environment. The inferior corrosion resistance of graphene-coated copper arises due to defects and poor surface coverage by graphene. Since it is prohibitively difficult to develop defect-free graphene on metals at a commercially feasible scale, this study investigated the hypothesis for an alternative approach, i.e., to develop multi-layer graphene with a reasonable assumption that the areas of defects/poor coverage of a layer will be masked by the subsequent over-layer(s. This study has validated this hypothesis. Electrochemical investigations have demonstrated multi-layer graphene to improve the corrosion resistance of a Cu-Ni alloy by an order of magnitude. However, the most striking finding of this study is that the improvement in corrosion resistance due to the multi-layer graphene coating sustained the entire duration of a long-term test (~350 h.

  7. Graphene: corrosion-inhibiting coating.

    Science.gov (United States)

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  8. Replacement of corrosion protection chromate primers and paints used in cryogenic applications on the Space Shuttle with wire arc sprayed aluminum coatings

    Science.gov (United States)

    Daniel, R. L.; Sanders, H. L.; Zimmerman, F. R.

    1995-01-01

    With the advent of new environmental laws restricting volatile organic compounds and hexavalent chrome emissions, 'environmentally safe' thermal spray coatings are being developed to replace the traditional corrosion protection chromate primers. A wire arc sprayed aluminum coating is being developed for corrosion protection of low pressure liquid hydrogen carrying ducts on the Space Shuttle Main Engine. Currently, this hardware utilizes a chromate primer to provide protection against corrosion pitting and stress corrosion cracking induced by the cryogenic operating environment. The wire are sprayed aluminum coating has been found to have good potential to provide corrosion protection for flight hardware in cryogenic applications. The coating development, adhesion test, corrosion test and cryogenic flexibility test results will be presented.

  9. Corrosion Protection of Phenolic-Epoxy/Tetraglycidyl Metaxylediamine Composite Coatings in a Temperature-Controlled Borax Environment

    Science.gov (United States)

    Xu, Wenhua; Wang, Zhenyu; Han, En-Hou; Liu, Chunbo

    2017-12-01

    The failure behavior for two kinds of phenolic-epoxy/tetraglycidyl metaxylediamine composite coatings in 60 °C borax aqueous solution was evaluated using electrochemical methods (EIS) combined with scanning electron microscopy, confocal laser scanning microscope, water immersion test, and Raman spectrum. The main focus was on the effect of curing agent on the corrosion protection of coatings. Results revealed that the coating cured by phenolic modified aromatic amine possessed more compact cross-linked structure, better wet adhesion, lower water absorption (0.064 mg h-1 cm-2) and its impedance values was closed to 108 Ω cm2 after immersion for 576 h, while the coating cured by modified aromatic ring aliphatic amine was lower than 105 Ω cm2. The corrosion mechanism of the two coatings is discussed.

  10. Sputter-ion plating of coatings for protection of gas-turbine blades against high-temperature oxidation and corrosion

    Science.gov (United States)

    Coad, J. P.; Restall, J. E.

    1982-01-01

    Considerable effort is being devoted to the development of overlay coatings for protecting critical components such as turbine blades against high-temperature oxidation, corrosion, and erosion damage in service. The most commercially advanced methods for depositing coatings are electron-beam evaporation and plasma spraying. Sputter-ion plating (SIP) offers a potentially cheaper and simpler alternative method for depositing overlays. Experimental work on SIP of Co-Cr-Al-Y and Ni-Cr-Al-Ti alloy coatings is described. Results are presented of metallographic assessment of these coatings, and of the results obtained from high-velocity testing using a gas-turbine simulator rig.

  11. Oleic acid-grafted chitosan/graphene oxide composite coating for corrosion protection of carbon steel.

    Science.gov (United States)

    Fayyad, Eman M; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Maadeed, Mariam Al Ali

    2016-10-20

    An anticorrosion coating film based on the formation of nanocomposite coating is reported in this study. The composite consisted of chitosan (green matrix), oleic acid, and graphene oxide (nano filler). The nanocomposite coating was arranged on the surface of carbon steel, and the corrosion resistance was monitored using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). Compared to the pure chitosan (CS) coating, the corrosion resistance of oleic acid-modified chitosan/graphene oxide film (CS/GO-OA) is increased by 100 folds. Since the well-dispersed smart grafted nanolayers delayed the penetration rate of corrosive species and thus maintained long term anticorrosive stability which is correlated with hydrophobicity and permeability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Hybrid nanostructured coatings for corrosion protection of base metals: a sustainability perspective

    Science.gov (United States)

    Dennis, Robert V.; Patil, Vikas; Andrews, Justin L.; Aldinger, Jeffrey P.; Yadav, Ganapati D.; Banerjee, Sarbajit

    2015-03-01

    In this topical review article, we attempt to capture recent advances in the development of sustainable hybrid nanocomposite coatings for the corrosion inhibition of structural metals. Spurred primarily by the urgent imperative of replacing hexavalent chromium but also driven by concerns regarding the environmental impact of organic solvents, materials criticality considerations, the need to maintain structural integrity and function under extreme environments, and a renewed impetus towards lightweighting, the design of new coating concepts has seen an explosion of activity. We discuss varying modes of corrosion inhibition and the drive towards multicomponent nanostructured coatings that synergistically unite multiple modes of corrosion inhibition within a single coating system. Nanocomposite coatings in which nanoparticles of one phase are dispersed within a continuous phase, usually a polymeric matrix, provide a modular design approach to multifunctional coatings provided fundamental challenges such as dispersion and compatibility can be resolved. By dint of their high surface-to-volume ratios, the incorporation of nanoparticles profoundly modifies the adjacent polymeric matrix, giving rise to an ‘interphase’ region with modified properties, at relatively low filler loadings. The implications of incorporating metallic, porous metal oxide, and carbon nanomaterials (graphene and carbon nanotubes) within polymeric matrices are explored with an emphasis on active corrosion inhibition. The availability of high-quality nanoparticles that are either electroactive (e.g., metals, graphene, carbon nanotubes, etc.) or are capable of serving as reservoirs for active corrosion inhibitors (e.g., porous silicon oxide, layered double hydroxides, halloysite) provides unprecedented functionality and opportunities for multifunctional coatings. The review emphasizes mechanistic considerations where these have been elucidated with a view towards developing systematic design

  13. Duplex Al-based thermal spray coatings for corrosion protection in high temperature refinery applications

    Directory of Open Access Journals (Sweden)

    Adriana da Cunha Rocha

    2004-03-01

    Full Text Available The application of thermal spray coatings has been effective in preventing corrosion of steel and iron products. It has been used in a wide range of applications spreading from the petroleum to the food industry. In this work, the performance and effectiveness of a two-layered aluminum-based thermal spray coating applied to an ASTM A387 G11 steel was evaluated. The coating structure was comprised of an inner Al-Fe-Cr layer and an outer layer of aluminum. Coated samples were tested in the reactor zone of a fluid catalytic cracking unit (FCCU of a petrochemical plant for 2.5 years. The reactor zone temperature was about 793 K (520 °C and the environment was a mixed gas containing sulfur, oxygen and carbon. Laboratory-scale tests were also conducted on the coated samples in order to gain a better understanding of the corrosive effect of the gaseous species present in the FCCU atmosphere. Porosity present in the thermal spray coatings allowed the penetration of the atmosphere corrodents, which instigated intergranular corrosion of the steel substrate. The presence of an inner Al-Fe-Cr layer did not prevent coating spallation, which further contributed to the internal corrosion process.

  14. IMPROVEMENT OF CORROSION PROTECTION OF PETROLEUM FACILITIES BY THE DEVELOPMENT OF A NEW HIGH-POTENTIAL COATING

    Energy Technology Data Exchange (ETDEWEB)

    Allaoua-Nazef, M.; Daouadji, M.

    2007-07-01

    Corrosion affects many oil and gas facilities. It is the principal cause of leaks of products and rupture of storage tanks and pipelines, resulting sometimes in catastrophic damages (human damages, pollution of the natural environment, additional costs for repair, prolonged stop of pumping). Growing environmental concerns regarding the use of heavy metals in anti-corrosion coating formulations led to a new coating strategy using intrinsically conducting polymers (ICPs) as key components. (ICPs) as a new materials class provides a unique set of new properties and coatings based on these polymers are able to meet high demands and are outperforming even the best conventional anti-corrosion coating systems. This new generation of high-potential coatings can provide a significant cost reduction for the oil and gas industry, due to the specific properties of the ICPs which can work indefinitely as a redox catalysts and provide continuous protection as long as the mechanical integrity of the polymer films remains intact. Our paper focuses on the development of a nonconventional coating based on a specific conducting polymer which is never used before in any coating formulations. The developed coating is able to provide high anticorrosion performances with safety, environmental benefits and costs reduction. (auth)

  15. Hydrothermal synthesis and corrosion behavior of the protective coating on Mg-2Zn-Mn-Ca-Ce alloy

    Directory of Open Access Journals (Sweden)

    Dan Song

    2016-12-01

    Full Text Available Protective coatings were synthesized on the Mg-2Zn-Mn-Ca-Ce Mg alloy through the hydrothermal method with de-ionized water as the reagent. The coatings were composed of Mg hydroxide, generally uniform and compact. Hydrogen evolution tests and electrochemical tests in the Hanks’ solution demonstrated that the Mg(OH2 coatings effectively decreased the bio-degradation rate of the Mg alloy substrate. Microstructure observation showed that the coating formation on the secondary phases was more difficult than that on the α-Mg matrix, which led to micro cracks and pores on the secondary phases after drying. Over synthesizing time, the coating layer on secondary phases gradually becomes more compact and uniform. Meanwhile, owing to the thicker and more compact coatings, the corrosion resistance and protective efficiency were significantly improved with longer synthesizing time as well.

  16. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.

    2010-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where they are needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into the microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy.

  17. Lithium salts as leachable corrosion inhibitors and potential replacement for hexavalent chromium in organic coatings for the protection of aluminum alloys

    NARCIS (Netherlands)

    Visser, P; Liu, Y; Terryn, H.A.; Mol, J.M.C.

    2016-01-01

    Lithium salts are being investigated as leachable corrosion inhibitor and potential replacement for hexavalent chromium in organic coatings. Model coatings loaded with lithium carbonate or lithium oxalate demonstrated active corrosion inhibition and the formation of a protective layer in a

  18. Biocompatibility and Corrosion Protection Behaviour of Hydroxyapatite Sol-Gel-Derived Coatings on Ti6Al4V Alloy

    Directory of Open Access Journals (Sweden)

    Amir A. El Hadad

    2017-01-01

    Full Text Available The aim of this work was to prepare hydroxyapatite coatings (HAp by a sol-gel method on Ti6Al4V alloy and to study the bioactivity, biocompatibility and corrosion protection behaviour of these coatings in presence of simulated body fluids (SBFs. Thermogravimetric/Differential Thermal Analyses (TG/DTA and X-ray Diffraction (XRD have been applied to obtain information about the phase transformations, mass loss, identification of the phases developed, crystallite size and degree of crystallinity of the obtained HAp powders. Fourier Transformer Infrared Spectroscopy (FTIR has been utilized for studying the functional groups of the prepared structures. The surface morphology of the resulting HAp coatings was studied by Scanning Electron Microscopy (SEM. The bioactivity was evaluated by soaking the HAp-coatings/Ti6Al4V system in Kokubo’s Simulated Body Fluid (SBF applying Inductively Coupled Plasma (ICP spectrometry. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT and Alamar blue cell viability assays were used to study the biocompatibility. Finally, the corrosion behaviour of HAp-coatings/Ti6Al4V system was researched by means of Electrochemical Impedance Spectroscopy (EIS. The obtained results showed that the prepared powders were nanocrystalline HAp with little deviations from that present in the human bone. All the prepared HAp coatings deposited on Ti6Al4V showed well-behaved biocompatibility, good bioactivity and corrosion protection properties.

  19. Biocompatibility and Corrosion Protection Behaviour of Hydroxyapatite Sol-Gel-Derived Coatings on Ti6Al4V Alloy.

    Science.gov (United States)

    El Hadad, Amir A; Peón, Eduardo; García-Galván, Federico R; Barranco, Violeta; Parra, Juan; Jiménez-Morales, Antonia; Galván, Juan Carlos

    2017-01-24

    The aim of this work was to prepare hydroxyapatite coatings (HAp) by a sol-gel method on Ti6Al4V alloy and to study the bioactivity, biocompatibility and corrosion protection behaviour of these coatings in presence of simulated body fluids (SBFs). Thermogravimetric/Differential Thermal Analyses (TG/DTA) and X-ray Diffraction (XRD) have been applied to obtain information about the phase transformations, mass loss, identification of the phases developed, crystallite size and degree of crystallinity of the obtained HAp powders. Fourier Transformer Infrared Spectroscopy (FTIR) has been utilized for studying the functional groups of the prepared structures. The surface morphology of the resulting HAp coatings was studied by Scanning Electron Microscopy (SEM). The bioactivity was evaluated by soaking the HAp-coatings/Ti6Al4V system in Kokubo's Simulated Body Fluid (SBF) applying Inductively Coupled Plasma (ICP) spectrometry. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and Alamar blue cell viability assays were used to study the biocompatibility. Finally, the corrosion behaviour of HAp-coatings/Ti6Al4V system was researched by means of Electrochemical Impedance Spectroscopy (EIS). The obtained results showed that the prepared powders were nanocrystalline HAp with little deviations from that present in the human bone. All the prepared HAp coatings deposited on Ti6Al4V showed well-behaved biocompatibility, good bioactivity and corrosion protection properties.

  20. Corrosion Behaviour of a Silane Protective Coating for NdFeB Magnets in Dentistry

    Directory of Open Access Journals (Sweden)

    Luigi Calabrese

    2015-01-01

    Full Text Available The corrosion behavior of coated and uncoated Ni/Cu/Ni rare earth magnets was assessed at increasing steps with a multilayering silanization procedure. Magnets’ durability was analyzed in Fusayama synthetic saliva solution in order to evaluate their application in dental field. Corrosion performance was evaluated by using polarization and electrochemical impedance spectroscopy in synthetic saliva solution up to 72 hours of continuous immersion. The results show that the addition of silane layers significantly improved anticorrosion properties. The coating and aging effects, in synthetic saliva solution, on magnetic field were evaluated by means of cyclic force-displacement curves.

  1. Direct Electrosynthesis of Polyaniline–Fe2O3 Nanocomposite Coating on Aluminum Alloy 5052 and Its Corrosion Protection Performance

    Directory of Open Access Journals (Sweden)

    M. Shabani-Nooshabadi

    2015-10-01

    Full Text Available The synthesis of polyaniline- Fe2O3 nanocomposite coating on aluminum Alloy 5052 (AA5052 surface has been investigated by using the galvanostatic method. The anticorrosion performance of polyaniline-Fe2O3 coating was investigated in 3.5% NaCl solution by the open- circuit potential (OCP, Tafel polarization technique and Electrochemical Impedance Spectroscopy (EIS. The corrosion rate of polyaniline-Fe2O3 nanocomposite coating AA5052 was found about140 times lower than bare AA5052. Corrosion potential also decreased from -0.710 V to -0.735 V versus Ag/AgCl for uncoated AA5052 and polyaniline-Fe2O3 nanocomposite coated on AA5052 electrodes, respectively. Electrochemical measurements show that polyaniline-Fe2O3 nanocomposite coated has good inhibitive properties with PE% of ~97.3% at 25 mA cm-2 current density applied on AA5052 corrosion in a chloride media. The results of this study clearly find out that the polyaniline-Fe2O3 nanocomposite has an outstanding possible to protect AA5052 against corrosion in a chloride environment.

  2. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    Science.gov (United States)

    Buhrow, Jerry; Li, Wenyan; Jolley, Scott; Calle, Luz M.

    2011-01-01

    A multifunctional, smart coating for the autonomous control of corrosion is being developed based on micro-encapsulation technology. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection effectiveness. This paper summarizes the development, optimization, and testing of microcapsules specifically designed to be incorporated into a smart coating that will deliver corrosion inhibitors to mitigate corrosion autonomously. Key words: smart coating, corrosion inhibition, microencapsulation, microcapsule, pH sensitive microcapsule, corrosion inhibitor, corrosion protection pain

  3. Development and evaluation of two PVD-coated β-titanium orthodontic archwires for fluoride-induced corrosion protection.

    Science.gov (United States)

    Krishnan, Vinod; Krishnan, Anand; Remya, R; Ravikumar, K K; Nair, S Asha; Shibli, S M A; Varma, H K; Sukumaran, K; Kumar, K Jyothindra

    2011-04-01

    The present research was aimed at developing surface coatings on β titanium orthodontic archwires capable of protection against fluoride-induced corrosion. Cathodic arc physical vapor deposition PVD (CA-PVD) and magnetron sputtering were utilized to deposit thin films of titanium aluminium nitride (TiAlN) and tungsten carbide/carbon (WC/C) coatings on β titanium orthodontic archwires. Uncoated and coated specimens were immersed in a high fluoride ion concentration mouth rinse, following a specially designed cycle simulating daily use. All specimens thus obtained were subjected to critical evaluation of parameters such as electrochemical corrosion behaviour, surface analysis, mechanical testing, microstructure, element release, and toxicology. The results confirm previous research that β titanium archwires undergo a degradation process when in contact with fluoride mouth rinses. The study confirmed the superior nature of the TiAlN coating, evident as many fewer changes in properties after fluoride treatment when compared with the WC/C coating. Thus, coating with TiAlN is recommended in order to reduce the corrosive effects of fluorides on β titanium orthodontic archwires. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Advanced Zinc Phosphate Conversion and Pre-Ceramic Polymetallosiloxane Coatings for Corrosion Protection of Steel and Aluminum, and Characteristics of Polyphenyletheretherketone-Based Materials

    Science.gov (United States)

    1992-09-24

    JÜ>AM*O 9WP BNL-48106 INFORMAL REPORT Advanced Zinc Phosphate Conversion and Pre-Ceramic ■ Polymetallosiloxane Coatings For Corrosion Protection...ment or any agency, contractor, or subcontractor thereof. Advanced Zinc Phosphate Conversion and Pre-Geraraic Poiymetallosiloxane Coatings For...L,„..„ r • n Advanced Zinc Phosphate Conversion ana Pre- Ceraraic Polymetallosiloxane Coatings for Corrosion Protec- tion of Steel and

  5. The corrosion protection of AA2024-T3 aluminium alloy by leaching of lithium-containing salts from organic coatings.

    Science.gov (United States)

    Visser, Peter; Liu, Yanwen; Zhou, Xiaorong; Hashimoto, Teruo; Thompson, George E; Lyon, Stuart B; van der Ven, Leendert G J; Mol, Arjan J M C; Terryn, Herman A

    2015-01-01

    Lithium carbonate and lithium oxalate were incorporated as leachable corrosion inhibitors in model organic coatings for the protection of AA2024-T3. The coated samples were artificially damaged with a scribe. It was found that the lithium-salts are able to leach from the organic coating and form a protective layer in the scribe on AA2024-T3 under neutral salt spray conditions. The present paper shows the first observation and analysis of these corrosion protective layers, generated from lithium-salt loaded organic coatings. The scribed areas were examined by scanning and transmission electron microscopy before and after neutral salt spray exposure (ASTM-B117). The protective layers typically consist of three different layered regions, including a relatively dense layer near the alloy substrate, a porous middle layer and a flake-shaped outer layer, with lithium uniformly distributed throughout all three layers. Scanning electron microscopy and white light interferometry surface roughness measurements demonstrate that the formation of the layer occurs rapidly and, therefore provides an effective inhibition mechanism. Based on the observation of this work, a mechanism is proposed for the formation of these protective layers.

  6. Investigation of Corrosion Behaviour of Aluminium Alloy Subjected to Laser Shock Peening without a Protective Coating

    Directory of Open Access Journals (Sweden)

    U. Trdan

    2015-01-01

    Full Text Available The effect of shock waves and strain hardening of laser shock peening without protective coating (LSPwC on alloy AA 6082-T651 was investigated. Analysis of residual stresses confirmed high compression in the near surface layer due to the ultrahigh plastic strains and strain rates induced by multiple laser shock waves. Corrosion tests in a chloride environment were carried out to determine resistance to localised attack, which was also verified on SEM/EDS. OCP transients confirmed an improved condition, that is, a more positive and stable potential after LSPwC treatment. Moreover, polarisation resistance of the LSPwC treated specimen was by a factor of 25 higher compared to the untreated specimen. Analysis of voltammograms confirmed an improved enhanced region of passivity and significantly smaller anodic current density of the LSPwC specimen compared to the untreated one. Through SEM, reduction of pitting attack at the LSPwC specimen surface was confirmed, despite its increased roughness.

  7. Emerging Corrosion Inhibitors for Interfacial Coating

    Directory of Open Access Journals (Sweden)

    Mona Taghavikish

    2017-12-01

    Full Text Available Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

  8. Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

    Science.gov (United States)

    Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

    2002-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

  9. Corrosion protection of SiC-based ceramics with CVDMullite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, V.; Auger, M. [Boston Univ., MA (United States)

    1997-05-01

    Silicon carbide ceramics are the leading candidate materials for use as heat exchangers in advanced combined cycle power plants because of their unique combination of high temperature strength, high thermal conductivity, excellent thermal shock resistance, and good high temperature stability and oxidation resistance. Ceramic coatings are being considered for diesel engine cylinder liners, piston caps, valve faces and seats, piston rings, and for turbine components such as combustors, blades, stators, seals, and bearings. Under such conditions ceramics are better suited to high temperature environments than metals. For the first time, adherent crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance its corrosion/oxidation resistance. Thermodynamic and kinetic considerations have been utilized to produce mullite coatings with a variety of growth rates, compositions, and morphologies. The flexibility of processing can be exploited to produce coated ceramics with properties tailored to specific applications and varied corrosive environments. These corrosive environments include thermal, Na{sub 2}SO{sub 4}, O{sub 2} and coal slag.

  10. Arc-Sprayed Fe-Based Coatings from Cored Wires for Wear and Corrosion Protection in Power Engineering

    Directory of Open Access Journals (Sweden)

    Korobov Yury

    2018-02-01

    Full Text Available High wear and corrosion of parts lead to an increase in operating costs at thermal power plants. The present paper shows a possible solution to this problem through the arc spraying of protective coatings. Cored wires of the base alloying system Fe-Cr-C were used as a feedstock. Rise of wear- and heat-resistance of the coatings was achieved by additional alloying with Al, B, Ti, and Y. The wear and heat resistance of the coatings were tested via a two-body wear test accompanied by microhardness measurement and the gravimetric method, respectively. A high-temperature corrosion test was performed at 550 °C under KCl salt deposition. The porosity and adhesion strengths of the coatings were also evaluated. The microstructure was investigated with a scanning electron microscope (SEM unit equipped with an energy dispersive X-ray (EDX microanalyzer, and the phase composition was assessed by X-ray diffractometry. The test results showed the positive influence of additional alloying with Y on the coating properties. A comparison with commercial boiler materials showed that the coatings have the same level of heat resistance as austenite steels and are an order of magnitude higher than that of pearlite and martensite-ferrite steels. The coatings can be applied to wear- and heat-resistant applications at 20–700 °C.

  11. Evaluation of the Corrosion Protection Coating in Accordance with Burn Damage

    Energy Technology Data Exchange (ETDEWEB)

    Seo, ChangHo; Park, JinHwan [Pukyong National University, Busan (Korea, Republic of)

    2016-12-15

    This study was conducted in order to examine the effect of burn damage and the resultant anti-corrosion performance. The breakdown and defect of the paint film caused by burn damage are considered to affect not only the macroscopic appearance but also the adhesive force and the anti-corrosion performance of the paint film. The material of the paint film was epoxy paint that is used most widely for heavy-duty coating, and in order to induce burn damage, heat treatment with a torch was applied to the other side of the paint film. Surface and chemical structure changes according to aging were analyzed using FE-SEM and infrared absorption spectroscopy, and variation in the anti-corrosion performance was analyzed through the AC impedance test.

  12. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, L. M.; Hintze, P. E.; Li, W.; Buhrow, J. W.; Jolley, S. T.

    2011-01-01

    This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

  13. Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners

    Energy Technology Data Exchange (ETDEWEB)

    Regina, J.R.

    2002-02-08

    Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

  14. SYNTHESIS AND CORROSION PROTECTION BEHAVIOR OF EPOXYTiO2-MICACEOUS IRON OXIDE NANO - COMPOSITE COATING ON St-37

    Directory of Open Access Journals (Sweden)

    M. R. Khorram

    2016-03-01

    Full Text Available The micro layers micaceous iron oxide and nano-TiO 2 were incorporated into the epoxy resin by mechanical mixing and sonication process. Optical micrographs showed that the number and diameter size of nanoparticle agglomerates were decreased by sonication. The structure and composition of the nanocomposite was determined using transmission electron microscopy which showed the presence of dispersed nano-TiO 2 in the polymer matrix. The anticorrosive properties of the synthesized nano-composites coating were investigated using salt spray, electrochemical impedance spectroscopy and polarization measurement. The EIS results showed that coating resistance increased by addition of micaceous iron oxide micro layers and nano-TiO 2 particles to the epoxy coatings. It was observed that higher corrosion protection of nanocomposite coatings obtained by the addition of 3 %wt micaceous iron oxide and 4%wt nano-TiO 2 into epoxy resin.

  15. MECHANICAL PROPERTIES AND CORROSION PROTECTION OF CARBON STEEL COATED WITH AN EPOXY BASED POWDER COATING CONTAINING MONTMORILONITE FUNCTIONALIZED WITH SILANE

    Directory of Open Access Journals (Sweden)

    Paula Tibola Bertuoli

    2014-06-01

    Full Text Available In the present work the MMT-Na+ clay was functionalized with 3-aminopropyltriethoxysilane (γ-APS and incorporated in a commercial formulation epoxy-based powder coating in a proportion of 8 wt% and applied on 1008 carbon steel panels by electrostatic spray. Adhesion, flexibility, impact and corrosion performance in salt spray chamber tests were performed to evaluate the coatings. The presence of clay did not affect the mechanical properties of the film, however greater subcutaneous migration was assessed after the completion of salt spray testing, which can compromise the use of paints obtained as primers.

  16. Hydrogen Silsesquioxane based silica glass coatings for the corrosion protection of austenitic stainless steel

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Din, Rameez Ud

    2016-01-01

    The application of stainless steels in hostile environments, such as concentrated acid or hot sea water, requires additional surface treatments, considering that the native surface oxide does not guarantee sufficient corrosion protection under these conditions. In the present work, silica-like thin...

  17. Composite coating with synergistic effect of biomimetic epoxy thermoset morphology and incorporated superhydrophobic silica for corrosion protection

    Directory of Open Access Journals (Sweden)

    W. F. Ji

    2016-11-01

    Full Text Available In this work, potential anticorrosive coating resulted from the composite with synergistic effect of biomimetic epoxy thermoset (BET morphology and incorporated superhydrophobic silica microspheres was presented. First of all, superhydrophobic methyl-modified silica (MS microspheres were synthesized by performing the conventional base-catalyzed sol-gel process of MTMS and APTMS. The as-prepared MS microspheres were identified as having an average particle size of ~1 µm in diameter. The as-prepared MS microspheres were characterized by Fourier transform infrared spectrometry (FTIR, 29Si and 13C solid-state nuclear magnetic resonance (NMR spectroscopy. Morphological properties of MS microspheres and BET-silica composite coating were studied by scanning electron microscopy (SEM. Subsequently, 3 wt% of MS microspheres were incorporated into an epoxy slurry of DGEBA/T-403 in dimetyl acetamide (DMAc, followed by performing the programmed heating through nanocasting technique with PDMS as soft template materials for pattern transfer by using leaf of Xanthosoma Sagittifolium as natural template, leading to the formation of artificial biomimetic composite coating. The appearance/dispersion capability of silica microspheres in BET coating was confirmed by the energy dispersive X-ray spectroscopy (EDX and Si-mapping. The roughness level of BET and BEC-3% were detected by AFM. The BETsilica composite was found to exhibit a contact angle (CA of ~153°, revealing the synergistic effect of biomimetic epoxy morphology and incorporated superhydrophobic MS microspheres, which is found to be more hydrophobic than that of neat epoxy thermoset (CA = 81°. Corrosion protection of as-prepared coatings was demonstrated by performing a series of electrochemical measurements (Tafel, Nyquists and Bode plots upon CRS electrodes in saline condition. It should be noted that the BET coatings upon CRS electrode revealed an effectively enhanced corrosion protection as compared

  18. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    Directory of Open Access Journals (Sweden)

    Florica Simescu and Hassane Idrissi

    2008-01-01

    Full Text Available We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO46(OH2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating.

  19. Effect of zinc phosphate chemical conversion coating on corrosion behaviour of mild steel in alkaline medium: protection of rebars in reinforced concrete

    Science.gov (United States)

    Simescu, Florica; Idrissi, Hassane

    2008-01-01

    We outline the ability of zinc phosphate coatings, obtained by chemical conversion, to protect mild steel rebars against localized corrosion, generated by chloride ions in alkaline media. The corrosion resistance of coated steel, in comparison with uncoated rebars and coated and uncoated steel rebars embedded in mortar, were evaluated by open-circuit potential, potentiodynamic polarization, cronoamperometry and electrochemical impedance spectroscopy. The coated surfaces were characterized by x-ray diffraction and scanning electron microscopy. First, coated mild steel rebars were studied in an alkaline solution with and without chloride simulating a concrete pore solution. The results showed that the slow dissolution of the coating generates hydroxyapatite Ca10(PO4)6(OH)2. After a long immersion, the coating became dense and provided an effective corrosion resistance compared with the mild steel rebar. Secondly, the coated and uncoated steel rebars embedded in mortar and immersed in chloride solution showed no corrosion or deterioration of the coated steel. Corrosion rate is considerably lowered by this phosphate coating. PMID:27878037

  20. Properties and performance of spin-on-glass coatings for the corrosion protection of stainless steels in chloride media

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette H.; Din, Rameez U.

    2018-01-01

    of the upper limit of the breakdown potential, there is also a decrease of the lower limit. It was found that such lower quality coatings showed, in association with substrate defects, unevenly distributed coating flaws, which may act as initiation points of pitting corrosion and decrease the corrosion...

  1. Synthesis of Graphene Oxide-Based Sulfonated Oligoanilines Coatings for Synergistically Enhanced Corrosion Protection in 3.5% NaCl Solution.

    Science.gov (United States)

    Lu, Hao; Zhang, Shengtao; Li, Weihua; Cui, Yanan; Yang, Tao

    2017-02-01

    As a vital derivative of graphene, graphene oxide (GO) is widely applied in various fields, such as transparent electrodes, solar cells, energy storage, and corrosion protection due to the large specific surface area and abundant active sites. However, compared with graphene, the application of GO has been less reported in metal corrosion protection field. Therefore, in our study, 3-aminobenzenesulfonic acid was selected to combine with oligoanilines to fabricate the GO-based sulfonated oligoanilines coatings for marine corrosion protection application. The obtained composite coatings were covered on the surface of Q235 steel, which is one of the most important structural marine materials. Fourier transform infrared spectra were utilized to prove the existence of different bonds and functional groups of aniline trimer and sulfonated aniline trimer (SAT). Scanning electron microscopy was applied to verify the combination of GO and SAT. What's more, transmission electron microscopy was applied to observe the surface appearance of the obtained GO-SAT composite material. Besides, the results of electrochemical measurements performed in 3.5 wt % NaCl solution showed excellent corrosion-protective properties of GO/SAT-coated epoxy resin with a dosage of 10 mg of GO compared with the pure epoxy resin. Moreover, the enhancement of surface hydrophobic property, to some extent, is in favor of preventing the absorption of corrosive medium and water molecules revealed by contact angle test. The addition of GO can make the diffusion pathway of the corrosive medium longer and more circuitous, while SAT has displayed excellent solvent solubility while maintaining corrosion-protective properties similar to those of polyanilines so that the corrosion-protective properties of the modified coatings improve significantly due to the synergistically enhanced corrosion protection of GO and SAT.

  2. Effects of aging temperature and time on the corrosion protection provided by trivalent chromium process coatings on AA2024-T3.

    Science.gov (United States)

    Li, Liangliang; Swain, Greg M

    2013-08-28

    The effects of aging temperature and time on the physical structure of and corrosion protection provided by trivalent chromium process (TCP) coatings on AA2024-T3 are reported. The TCP coating forms a partially blocking barrier layer on the alloy surface that consists of hydrated channels and or defects. It is through these channels and defects that ions and dissolved O2 can be transported to small areas of the underlying alloy. Reactions initiate at these sites, which can ultimately lead to undercutting of the coating and localized corrosion. We tested the hypothesis that collapsing the channels and or reducing the number of defects in the coating might be possible through post-deposition heat treatment, and that this would enhance the corrosion protection provided by the coating. This was tested by aging the TCP-coated AA2024 alloys in air overnight at room temperature (RT), 55, 100, or 150 °C. The TCP coating became dehydrated and thinner at the high temperatures (55 and 100 °C). This improved the corrosion protection as evidenced by a 2× increase in the charge transfer resistance. Aging at 150 °C caused excessive coating dehydration and shrinkage. This led to severe cracking and detachment of the coating from the surface. The TCP-coated AA2024 samples were also aged in air at RT from 1 to 7 days. There was no thinning of the coating, but the corrosion protection was enhanced with a longer aging period as evidenced by a 4× increase in the charge transfer resistance. The coating became more hydrophobic after aging at elevated temperature (up to 100 °C) and with aging time at RT as evidenced by an increased water contact angle from 7 to 100 °C.

  3. Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

    Science.gov (United States)

    Regina, Jonathan R.

    The current study investigated the effect of chromium additions on the hydrogen cracking susceptibility of Fe-Al weld overlay claddings containing chromium additions. It was found that the weldability of FeAlCr claddings was a function of both the aluminum and chromium concentrations of the weld coatings. Weld overlay compositions that were not susceptible to hydrogen cracking were identified and the underlying mechanism behind the hydrogen cracking phenomenon was investigated further. It was concluded that the cracking behavior of the FeAlCr welds depended strongly on the microstructure of the weld fusion zone. Although it was found that the cracking susceptibility was influenced by the presence of Fe-Al intermetallic phases (namely Fe3 Al and FeAl), the cracking behavior of FeAlCr weld overlay claddings also depended on the size and distribution of carbide and oxide particles present within the weld structure. These particles acted as hydrogen trapping sites, which are areas where free hydrogen segregates and can no longer contribute to the hydrogen embrittlement of the metal. It was determined that in practical applications of these FeAlCr weld overlay coatings, carbon should be present within these welds to reduce the amount of hydrogen available for hydrogen cracking. Based on the weldability results of the FeAlCr weld claddings, coating compositions that were able to be deposited crack-free were used for long-term corrosion testing in a simulated low NOx environment. These alloys were compared to a Ni-based superalloy (622), which is commonly utilized as boiler tube coatings in power plant furnaces for corrosion protection. It was found that the FeAlCr alloys demonstrated superior corrosion resistance when compared to the Ni-based superalloy. Due to the excellent long-term corrosion behavior of FeAlCr weld overlays that were immune to hydrogen cracking, it was concluded that select FeAlCr weld overlay compositions would make excellent corrosion resistant

  4. Launch Pad Coatings for Smart Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

    2010-01-01

    Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

  5. Corrosion behavior of duplex coatings

    Directory of Open Access Journals (Sweden)

    K. Raghu Ram Mohan Reddy

    2016-07-01

    Full Text Available The titanium alloys are used in defense, aerospace, automobile, chemical plants and biomedical applications due to their very high strength and lightweight properties. However, corrosion is a life-limiting factor when Ti alloys are exposed to different chemical environments at high temperatures. In the present paper, duplex NiCrAlY/WC–Co coating is coated onto Ti6Al4V substrate to investigate the corrosion behavior of both coated samples and the substrate. The duplex coating was performed with NiCrAlY as the intermediate coat of 200 μm thickness deposited by HVOF process and WC–Co ceramic top coat with varying thicknesses of 250 μm, 350 μm and 450 μm deposited by DS process. Potentiodynamic polarization tests were employed to investigate the corrosion performance of duplex coated samples and substrate in Ringer’s solution at 37 °C and pH value was set to 5.7. Finally the results reveal that 350 μm thick coated samples showed highest corrosion resistance compared to 250 μm thick samples as well as bare substrate. However, the 450 μm thick coated sample showed poor corrosion resistance compared to the substrate. The scale formed on the samples upon corrosion was characterized by using SEM analysis to understand the degree of corrosion behavior.

  6. Study of the Effect of Sol pH and Nanoclay Incorporation on the Corrosion Protection Performance of a Silane Sol-Gel Coating

    Directory of Open Access Journals (Sweden)

    Najmeh Asadi

    2014-06-01

    Full Text Available This work is aimed to evaluate the role of nanoclay in the protective performance of an eco-friendly silane sol-gel layer applied on mild steel substrate in 0.1M sodium chloride solution. At the first step, the effect of pH of the silane solution, consisting of a mixture of γ-glycidoxypropiltrimethoxysilane and methyltriethoxysilane and tetraethoxysilane, on the coating performance was evaluated through electrochemical noise measurements. The values of characteristic charge as a parameter extracted from shot noise theory revealed that the sol pH determining the rate of hydrolysis can play an important role in the corrosion protection behavior of silane coatings. Then, the influence of clay nanoparticles on the corrosion protective performance of the hybrid silane film was studied through taking advantage of electrochemical techniques, including electrochemical impedance spectroscopy and polarization curves, as well as surface analysis methods. The obtained electrochemical data including the values of charge transfer resistance, coating resistance, low frequency impedance and corrosion current density showed that the silane sol gel film in the presence of clay nanoparticles can present an improved corrosion protection. The behavior was connected to an enhancement in the coating barrier properties. Moreover, FESEM and water contact angle confirmed the higher reticulation in case of the coating incorporating nanoclay.

  7. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides

    Science.gov (United States)

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

  8. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  9. Field investigation of the corrosion protection performance of bridge decks and piles constructed with epoxy-coated reinforcing steel in Virginia.

    Science.gov (United States)

    1997-10-01

    The corrosion protection performance of epoxy-coated reinforcing steel (ECR) was assessed in three bridge decks and the piles : in three marine structures in Virginia in 1996. The decks were 17 years old, two of the marine structures were 8 years old...

  10. Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel

    Science.gov (United States)

    Elsawy, Abdel Raouf

    This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation

  11. Corrosion-resistant coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  12. Corrosion Protection Properties of Nano NH₂-Reduced Graphene Oxide/Epoxy Composite Coatings Formed by Self-Curing on Magnesium Alloy.

    Science.gov (United States)

    Jin, Tao; Han, Yongqin; Bai, Ruiqin; Liu, Xin

    2018-07-01

    Nano NH2-reduced graphene oxide (NGO) and NGO/epoxy resin coatings were prepared, respectively. NGO/epoxy coating was successfully coated on magnesium alloy substrates. X-ray diffraction patterns, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques were used to characterize the composition and morphology of NGO and composite coatings. The effect of the content of NGO on the corrosion protection performance of coatings was evaluated with electrochemical measurements in 3.5 wt.% NaCl solutions. Tafel and electrochemical impedance spectroscopy analysis revealed that an optimal addition amount of 0.3 wt.% NGO provided the superior corrosion protection properties. The composite coatings exhibited outstanding barrier properties against aggressive species compared to pure epoxy coating. The self-curing reaction of amine and epoxy radicals could produce the compact cross-linking reticular structure. This self-curing reaction was a nucleophilic addition, and amine radical preferred to bond the (b) site of graphene sheets due to the lowest Gibbs free energy. The cross-linking structure and some polar groups could act as a good reservoir for corrosive medium via absorption and fixation.

  13. Aluminide slurry coatings for protection of ferritic steel in molten nitrate corrosion for concentrated solar power technology

    Science.gov (United States)

    Audigié, Pauline; Bizien, Nicolas; Baráibar, Ignacio; Rodríguez, Sergio; Pastor, Ana; Hernández, Marta; Agüero, Alina

    2017-06-01

    Molten nitrates can be employed as heat storage fluids in solar concentration power plants. However molten nitrates are corrosive and if operating temperatures are raised to increase efficiencies, the corrosion rates will also increase. High temperature corrosion resistant coatings based on Al have demonstrated excellent results in other sectors such as gas turbines. Aluminide slurry coated and uncoated P92 steel specimens were exposed to the so called Solar Salt (industrial grade), a binary eutectic mixture of 60 % NaNO3 - 40 % KNO3, in air for 2000 hours at 550°C and 580°C in order to analyze their behavior as candidates to be used in future solar concentration power plants employing molten nitrates as heat transfer fluids. Coated ferritic steels constitute a lower cost technology than Ni based alloy. Two different coating morphologies resulting from two heat treatment performed at 700 and 1050°C after slurry application were tested. The coated systems exhibited excellent corrosion resistance at both temperatures, whereas uncoated P92 showed significant mass loss from the beginning of the test. The coatings showed very slow reaction with the molten Solar Salt. In contrast, uncoated P92 developed a stratified, unprotected Fe, Cr oxide with low adherence which shows oscillating Cr content as a function of coating depth. NaFeO2 was also found at the oxide surface as well as within the Fe, Cr oxide.

  14. Optimization of In-Situ Shot-Peening-Assisted Cold Spraying Parameters for Full Corrosion Protection of Mg Alloy by Fully Dense Al-Based Alloy Coating

    Science.gov (United States)

    Wei, Ying-Kang; Luo, Xiao-Tao; Li, Cheng-Xin; Li, Chang-Jiu

    2017-01-01

    Magnesium-based alloys have excellent physical and mechanical properties for a lot of applications. However, due to high chemical reactivity, magnesium and its alloys are highly susceptible to corrosion. In this study, Al6061 coating was deposited on AZ31B magnesium by cold spray with a commercial Al6061 powder blended with large-sized stainless steel particles (in-situ shot-peening particles) using nitrogen gas. Microstructure and corrosion behavior of the sprayed coating was investigated as a function of shot-peening particle content in the feedstock. It is found that by introducing the in-situ tamping effect using shot-peening (SP) particles, the plastic deformation of deposited particles is significantly enhanced, thereby resulting in a fully dense Al6061 coating. SEM observations reveal that no SP particle is deposited into Al6061 coating at the optimization spraying parameters. Porosity of the coating significantly decreases from 10.7 to 0.4% as the SP particle content increases from 20 to 60 vol.%. The electrochemical corrosion experiments reveal that this novel in-situ SP-assisted cold spraying is effective to deposit fully dense Al6061 coating through which aqueous solution is not permeable and thus can provide exceptional protection of the magnesium-based materials from corrosion.

  15. Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions

    Science.gov (United States)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

  16. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Science.gov (United States)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

  17. Corrosion performance of inorganic coatings in seawater

    NARCIS (Netherlands)

    Zhang, X.; Buter, S.J.; Ferrari, G.M.; Westing, E. van; Kowalski, L.

    2011-01-01

    Inorganic coatings are widely used to protect carbon steel hydraulic cylinder rods from wear and corrosion in aggressive offshore environment. Different types of lay-ers such as Ni/Cr, Al2O3, Cr2O3, TiO2, and Inconel 625 layers were applied to the carbon steels by plasma, High Velocity Oxygen Fuel

  18. Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Coffman, Brekke E.; Coffman, Brekke E.; Curran, Jerome P.; Kolody, Mark R.; Whitten, Mary; Perisich, Steven; hide

    2009-01-01

    When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC).

  19. A Multifunctional Smart Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz Marina; Buhrow, Jerry W.; Jolley, Scott T.

    2012-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on micro-encapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

  20. Self-Assembled Films as Corrosion Protective Coatings for Metal Surfaces

    National Research Council Canada - National Science Library

    Robinson, Gary

    1996-01-01

    .... Monolayers of stearic acid on aluminum surfaces were found to profoundly affect the wettability of Al surfaces by concentrated sulfuric acid, but not to act as a significant barrier to corrosion...

  1. Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

    Science.gov (United States)

    Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

    2016-11-01

    Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016. © 2015 Wiley Periodicals, Inc.

  2. Deposition and characterization of sol-gel alumina coatings on commercial power plant steels for corrosion protection against oxyfuel combustion atmosphere

    OpenAIRE

    Schulz, Wencke

    2016-01-01

    The objective of the present work was the investigation and demonstration of the potential of sol-gel alumina layers as corrosion protection of commercial power plant steels under oxyfuel conditions. The starting points of this work were modified Yoldas-sols which were developed in the BAM-department 5.6. These sols were suitable for the spin-coating method only. The application of coatings on tubes by spin-coating is impossible. Therefore, the chemical composition of the modified Yoldas-sol ...

  3. Protection against corrosion to high temperature by means of rich silicon coatings; Proteccion contra corrosion a alta temperatura por medio de recubrimientos ricos en silicio

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    In this research work the study of the process of corrosion by molten salts of sodium sulphate-vanadium pentoxide and its prevention by means of metallic coatings rich in silicon was contemplated. The research encompassed the development of the coating system, the chemical and thermochemical analysis of the system sodium sulphate - vanadium pentoxide, the evaluation of the resistance to the corrosion of the coating system by gravimetric and electrochemistry techniques, and the study of the stability of the coating system - substrate. [Spanish] En este trabajo de investigacion se contempla el estudio del proceso de corrosion por sales fundidas de sulfato de sodio - pentoxido de vanadio y su prevencion por medio de recubrimientos metalicos ricos en silicio. La investigacion abarca el desarrollo del sistema de recubrimientos, el analisis quimico y termoquimico del sistema sulfato de sodio - pentoxido de vanadio, la evaluacion de la resistencia a la corrosion del sistema de recubrimientos por tecnicas gravimetricas y electroquimicas, y el estudio de la estabilidad del sistema recubrimiento - sustrato.

  4. Architectural optimization of an epoxy-based hybrid sol–gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Murillo-Gutiérrez, N.V., E-mail: murillo@chimie.ups-tlse.fr [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Ansart, F.; Bonino, J-P. [Université de Toulouse UPS-INP-CNRS, Institut Carnot CIRIMAT, Toulouse (France); Kunst, S.R.; Malfatti, C.F. [Universidade Federal do Rio grande do Sul, Laboratory of Corrosion Research (LAPEC), Porto Alegre (Brazil)

    2014-08-01

    An epoxy-based hybrid sol–gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol–gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol–gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  5. Application of the aqueous coating suspension for the protection of Gas Turbine Engine parts from corrosion

    Directory of Open Access Journals (Sweden)

    E. G. Ivanov

    2015-01-01

    Full Text Available The article considers the physical nature of receiving diffusion coatings from aqueous suspensions of various alloys for various conditions and their further exploitation. Structure of coatings, advantages and features of the production of coatings from aqueous suspensions are shown. Based on the analysis of thermodynamic reactions in the systems of elements formulations of aqueous suspensions were developed and practical recommendations for their application to the parts of gas turbine engine were given.

  6. Space Shuttle Corrosion Protection Performance

    Science.gov (United States)

    Curtis, Cris E.

    2007-01-01

    The reusable Manned Space Shuttle has been flying into Space and returning to earth for more than 25 years. The launch pad environment can be corrosive to metallic substrates and the Space Shuttles are exposed to this environment when preparing for launch. The Orbiter has been in service well past its design life of 10 years or 100 missions. As part of the aging vehicle assessment one question under evaluation is how the thermal protection system and aging protective coatings are performing to insure structural integrity. The assessment of this cost resources and time. The information is invaluable when minimizing risk to the safety of Astronauts and Vehicle. This paper will outline a strategic sampling plan and some operational improvements made by the Orbiter Structures team and Corrosion Control Review Board.

  7. Silica nanocontainers for active corrosion protection.

    Science.gov (United States)

    Maia, Frederico; Tedim, João; Lisenkov, Aleksey D; Salak, Andrei N; Zheludkevich, Mikhail L; Ferreira, Mário G S

    2012-02-21

    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. This journal is © The Royal Society of Chemistry 2012

  8. 120 DEG C Cure, Durable, Corrosion Protection Powder Coatings for Temperature Sensitive Substrates

    Science.gov (United States)

    2005-01-28

    functional acrylics •Phenol functional resins Crosslinkers •Blocked isocyanates •Uretidiones Catalysts •Lewis Acids • Bismuth carboxylates •N,N...inhibitor, (1-benzothiazol-2-ylthio) succinic acid (Irgacor 252LD) were also tested. 72 Table 5.2 Eight corrosion...2-ylthio) Succinic Acid F Zinc Phosphate Zinc Phosphate G CW-491 Calcium Phosphosilicate H Test Substrates Chromated and untreated aluminum

  9. Corrosion Protection of Electrically Conductive Surfaces

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-11-01

    Full Text Available The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is a relative movement between electrical contacts with surfaces of ignoble metal. Avoiding fretting corrosion is therefore extremely challenging in electronic devices with pluggable electrical connections. Gold is one of the most commonly used noble plating materials for high performance electrical contacts because of its high corrosion resistance and its good and stable electrical behavior. The authors have investigated different ways to minimize the consumption of gold for electrical contacts and to improve the performance of gold plating. Other plating materials often used for corrosion protection of electrically conductive surfaces are tin, nickel, silver and palladium. This paper will deal with properties and new research results of different plating materials in addition to other means used for corrosion protection of electrically conductive surfaces and the testing of corrosion resistance of electrically conductive surfaces.

  10. Protective coatings for intraocular wirelessly controlled microrobots for implantation: Corrosion, cell culture, and in vivo animal tests.

    Science.gov (United States)

    Pokki, Juho; Ergeneman, Olgaç; Chatzipirpiridis, George; Lühmann, Tessa; Sort, Jordi; Pellicer, Eva; Pot, Simon A; Spiess, Bernhard M; Pané, Salvador; Nelson, Bradley J

    2017-05-01

    Diseases in the ocular posterior segment are a leading cause of blindness. The surgical skills required to treat them are at the limits of human manipulation ability, and involve the risk of permanent retinal damage. Instrument tethering and design limit accessibility within the eye. Wireless microrobots suturelessly injected into the posterior segment, steered using magnetic manipulation are proposed for procedures involving implantation. Biocompatibility is a prerequisite for these procedures. This article investigates the use of polypyrrole- and gold-coated cobalt-nickel microrobots. While gold has been used in ocular implants, no ocular implantation involving polypyrrole is reported, despite its well-established biocompatibility properties. Coated and uncoated microrobots were investigated for their corrosion properties, and solutions that had contained coated and uncoated microrobots for one week were tested for cytotoxicity by monitoring NIH3T3 cell viability. None of the microrobots showed significant corrosion currents and corrosion potentials were as expected in relation to the intrinsic nobility of the materials. NIH3T3 cell viability was not affected by the release medium, in which coated/uncoated microrobots were stored. In vivo tests inside rabbit eyes were performed using coated microrobots. There were no significant inflammatory responses during the first week after injection. An inflammatory response detected after 2 weeks was likely due to a lack of longer-duration biocompatibility. The results provide valuable information for those who work on implant technology and biocompatibility. Coated microrobots have the potential to facilitate a new generation of surgical treatments, diagnostics and drug-delivery techniques, when implantation in the ocular posterior segment will be possible. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 836-845, 2017. © 2016 Wiley Periodicals, Inc.

  11. The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

    Science.gov (United States)

    Danford, M. D.

    1993-01-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  12. Co-sputtered amorphous Nb–Ta, Nb–Zr and Ta–Zr coatings for corrosion protection of cyclotron targets for [{sup 18}F] production

    Energy Technology Data Exchange (ETDEWEB)

    Skliarova, Hanna, E-mail: Hanna.Skliarova@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); University of Ferrara, Ferrara (Italy); Azzolini, Oscar, E-mail: Oscar.Azzolini@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); Johnson, Richard R., E-mail: richard.johnson@teambest.com [BEST Cyclotron Systems Inc., 8765 Ash Street Unit 7, Vancouver, BC V6P 6T3 (Canada); Palmieri, Vincenzo, E-mail: Vincenzo.Palmieri@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell’Università, 2, 35020 Legnaro, Padua (Italy); University of Padua, Padua (Italy)

    2015-08-05

    Highlights: • Nb–Ta, Nb–Zr and Ta–Zr alloy films were deposited by co-sputtering. • Co-sputtered Nb–Zr and Nb–Ta alloy coatings had crystalline microstructures. • Diffusion barrier efficiency of Nb–Zr and Nb–Ta decreased with the increase of Nb %. • Co-sputtered Ta–Zr films with 30–73 at.% Ta were amorphous. • Sputtered amorphous Ta–Zr films showed superior diffusion barrier efficiency. - Abstract: Protective corrosion resistant coatings serve for decreasing the amount of ionic contaminants from Havar® entrance foils of the targets for [{sup 18}F] production. The corrosion damage of coated entrance foils is caused mainly by the diffusion of highly reactive products of water radiolysis through the protective film toward Havar® substrate. Since amorphous metal alloys (metallic glasses) are well-known to perform a high corrosion resistance, the glass forming ability, microstructure and diffusion barrier efficiency of binary alloys containing chemically inert Nb, Ta, Zr were investigated. Nb–Ta, Nb–Zr and Ta–Zr films of different alloy composition and ∼1.5 μm thickness were co-deposited by magnetron sputtering. Diffusion barrier efficiency tests used reactive aluminum underlayer and protons of acid solution and gallium atoms at elevated temperature as diffusing particles. Though co-sputtered Nb–Ta and Nb–Zr alloy films of different contents were crystalline, Ta–Zr alloy was found to form dense amorphous microstructures in a range of composition with 30–73% atomic Ta. The diffusion barrier efficiency of Nb–Zr and Nb–Ta alloy coatings decreased with increase of Nb content. The diffusion barrier efficiency of sputtered Ta–Zr alloy coatings increased with the transition from nanocrystalline columnar microstructure to amorphous for coatings with 30–73 at.% Ta.

  13. The effect of cerium-based conversion treatment on the cathodic delamination and corrosion protection performance of carbon steel-fusion-bonded epoxy coating systems

    Science.gov (United States)

    Ramezanzadeh, B.; Rostami, M.

    2017-01-01

    The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.

  14. HVOF Thermal Spray TiC/TiB2 Coatings for AUSC Boiler/Turbine Components for Enhanced Corrosion Protection

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Kanchan [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes; Koc, Rasit [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Mechanical Engineering and Energy Processes; Fan, Chinbay [Gas Technology Inst., Des Plaines, IL (United States)

    2016-12-07

    The high temperatures of operations still pose significant risk of degradation and fatigue from oxidizing, corroding and eroding environment. In addition to unused O2, water from combustion and SOx from the coal sulfur oxidation that result in highly corrosive environment, acid gases such as HCl and other sulfur compounds may also be present. These adverse effects are further accelerated due to the elevated temperatures. In addition, ash particulates and unburnt carbon and pyritic sulfur can cause erosion of the surface and thus loss of material. Unburnt carbon and pyritic sulfur may also cause localized reduction sites. Thus, fireside corrosion protection and steam oxidation protection alternatives to currently used Ni-Cr overlays need to be identified and evaluated. Titanium carbide (TiC) is a suitable alternative on account of the material features such as the high hardness, the high melting point, the high strength and the low density for the substitution or to be used in conjunction with NiCr for enhancing the fireside corrosion and erosion of the materials. Another alternative is the use of titanium boride as a coating for chemical stability required for long-term service and high erosion resistance over the state-of-the-art, high fracture toughness (K1C ~12 MPam1/2) and excellent corrosion resistance (kp~1.9X10-11 g2/cm4/s at 800°C in air). The overarching aim of the research endeavor was to synthesize oxidation, corrosion and wear resistant TiC and TiB2 coating powders, apply thermal spray coating on existing boiler materials and characterize the coated substrates for corrosion resistance for applications at high temperatures (500 -750 °C) and high pressures (~350 bars) using the HVOF process and to demonstrate the feasibility of these coating to be used in AUSC boilers and turbines.

  15. Microencapsulation of Corrosion Indicators for Smart Coatings

    Science.gov (United States)

    Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.; Calle, Luz M.; Hanna,Joshua S.; Rawlins, James W.

    2011-01-01

    A multifunctional smart coating for the autonomous detection, indication, and control of corrosion is been developed based on microencapsulation technology. This paper summarizes the development, optimization, and testing of microcapsules specifically designed for early detection and indication of corrosion when incorporated into a smart coating. Results from experiments designed to test the ability of the microcapsules to detect and indicate corrosion, when blended into several paint systems, show that these experimental coatings generate a color change, indicative of spot specific corrosion events, that can be observed with the naked eye within hours rather than the hundreds of hours or months typical of the standard accelerated corrosion test protocols.. Key words: smart coating, corrosion detection, microencapsulation, microcapsule, pH-sensitive microcapsule, corrosion indicator, corrosion sensing paint

  16. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    Science.gov (United States)

    Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  17. The effect of cerium-based conversion treatment on the cathodic delamination and corrosion protection performance of carbon steel-fusion-bonded epoxy coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanzadeh, B., E-mail: ramezanzadeh@aut.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Department of Nanomaterials and Nanocoatings, Institute for Color Science and Technology (ICST), 16765-654, Tehran (Iran, Islamic Republic of)

    2017-01-15

    Highlights: • Steel surface was treated by Ce and acid phosphoric solutions. • Ce treatment considerably enhanced the surface energy and produce nanoscale roughness. • Ce treated samples showed enhanced adhesion to FBE coating. • Ce treatment of steel significantly reduced the FBE cathodic delamination rate. • Ce treated sample showed enhanced corrosion resistance. - Abstract: The effect of surface pre-treatment of pipe surface by green cerium compound and phosphoric acid solution on the fusion-bonded epoxy (FBE) coating performance was studied. The composition and surface morphology of the steel samples treated by acid and Ce solutions were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), equipped with energy dispersive spectroscopy (EDS). Also, the surface free energy was evaluated on these samples through contact angle measurements. In addition, the effect of Ce and acid washing procedures on the adhesion properties and corrosion protection performance of the FBE was examined by pull-off, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results showed that compared to acid washing, the chemical treatment by Ce solution noticeably increased the surface free energy of steel, improved the adhesion properties of FBE, decreased the cathodic delamination rate of FBE, and enhanced the coating corrosion resistance compared to the acid washed samples.

  18. Electroless Deposition of Ni-Cu-P Coatings Containing Nano-Al2O3 Particles and Study of Its Corrosion Protective Behaviour in 0.5 M H2SO4

    OpenAIRE

    H. Ashassi-Sorkhabi; Aminikia, H.; R. Bagheri

    2014-01-01

    Ni-Cu-P/nano-Al2O3 composite coatings are prepared on mild steel from an alkaline electroless plating bath containing different concentrations of Al2O3 nanoparticles. The protective effect of codeposited nanoparticles on the corrosion behaviour of the coatings is studied in 0.5 M H2SO4 solution. The electrochemical methods, that is, electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization measurements, are used to characterize the corrosion properties of the...

  19. Two-shell structured PMAA@CeO2nanocontainers loaded with 2-mercaptobenzothiazole for corrosion protection of damaged epoxy coated AA 2024-T3.

    Science.gov (United States)

    Balaskas, A C; Hashimoto, T; Curioni, M; Thompson, G E

    2017-05-04

    In this work, novel two-shell structured inhibitor-loaded poly(methacrylic acid)@cerium oxide (PMAA@CeO 2 ) nanocontainers were synthesised and characterized. The purpose of the nanocontainers is to increase the corrosion protection provided by an epoxy coating applied to an aerospace alloy (AA 2024-T3). The (PMAA@CeO 2 ) nanocontainers with diameters of 550 nm were synthesised by a four-step process with the method of distillation precipitation polymerization for the synthesis of the inner PMAA layer, and the sol-gel method for the development of the outer CeO 2 layer. The loaded nanocontainers were characterized by scanning and transmission electron microscopies. The corrosion protection properties of the epoxy coated AA 2024-T3 with 2-mercaptobenzothiazole (2-MBT) loaded PMAA@CeO 2 nanocontainers were evaluated with and without artificial scribes by electrochemical impedance spectroscopy (EIS). The results indicated that the epoxy coating containing the 2-MBT-loaded nanocontainers provided enhanced protection of the AA 2024-T3 substrate.

  20. Mesoporous silica nanoparticles for active corrosion protection.

    Science.gov (United States)

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect.

  1. Thermal spray coating for corrosion under insulation (CUI) prevention

    Science.gov (United States)

    Fuad, Mohd Fazril Irfan Ahmad; Razak, Khalil Abdul; Alias, Nur Hashimah; Othman, Nur Hidayati; Lah, Nik Khairul Irfan Nik Ab

    2017-12-01

    Corrosion under insulation (CUI) is one of the predominant issues affecting process of Oil and Gas and Petrochemical industries. CUI refers to external corrosion, but it is difficult to be detected as the insulation cover masks the corrosion problem. One of the options to prevent CUI is by utilizing the protective coating systems. Thermal spray coating (TSC) is an advanced coating system and it shows promising performance in harsh environment, which could be used to prevent CUI. However, the application of TSC is not attractive due to the high initial cost. This work evaluates the potential of TSC based on corrosion performance using linear polarization resistance (LPR) method and salt spray test (SST). Prior to the evaluation, the mechanical performance of TSC was first investigated using adhesion test and bend test. Microstructure characterization of the coating was investigated using Scanning Electron Microscope (SEM). The LPR test results showed that low corrosion rate of 0.05 mm/years was obtained for TSC in compared to the bare steel especially at high temperature of 80 °C, where usually normal coating would fail. For the salt spray test, there was no sign of corrosion products especially at the center (fully coated region) was observed. From SEM images, no corrosion defects were observed after 336 hours of continuous exposure to salt fog test. This indicates that TSC protected the steel satisfactorily by acting as a barrier from a corrosive environment. In conclusion, TSC can be a possible solution to minimize the CUI in a long term. Further research should be done on corrosion performance and life cycle cost by comparing TSC with other conventional coating technology.

  2. Synergistic Effect of Polypyrrole-Intercalated Graphene for Enhanced Corrosion Protection of Aqueous Coating in 3.5% NaCl Solution.

    Science.gov (United States)

    Qiu, Shihui; Li, Wei; Zheng, Wenru; Zhao, Haichao; Wang, Liping

    2017-10-04

    Dispersion of graphene in water and its incorporation into waterborne resin have been rarely researched and hardly achieved owing to its hydrophobicity. Furthermore, it has largely been reported that graphene with impermeability contributed to the improved anticorrosion property. Here, we show that highly concentrated graphene aqueous solution up to 5 mg/mL can be obtained by synthesizing hydrophilic polypyrrole (PPy) nanocolloids as intercalators and ultrasonic vibration. On the basis of π-π interaction between PPy and graphene, stacked graphene sheets are exfoliated to the thickness of three to five layers without increasing defects. The corrosion performance of coatings without and with PPy and graphene is obtained by potential and impedance measurements, Tafel curves, and fitted pore resistance by immersing in a 3.5 wt % NaCl solution. It turns out that composite coating with 0.5 wt % graphene additive exhibits superior anticorrosive ability. The mechanism of intercalated graphene-based coating is interpreted as the synergistic protection of impermeable graphene sheets and self-healing PPy and proved by the identification of corrosion products and the scanning vibrating electrode technique.

  3. Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

    Directory of Open Access Journals (Sweden)

    Jolanta Gąsiorek

    2018-01-01

    Full Text Available Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

  4. Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation.

    Science.gov (United States)

    Gąsiorek, Jolanta; Szczurek, Anna; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

    2018-01-26

    Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

  5. The corrosion protection of 2219-T87 aluminum by anodizing

    Science.gov (United States)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  6. Nano-structured sol–gel coatings as protective films against zinc corrosion in 0.5 M HCl solution

    Directory of Open Access Journals (Sweden)

    Shimaa M. Ali

    2017-05-01

    Full Text Available The protection abilities of unmodified and modified GPTMS-VTMS sol–gel films with different Ti- and Al-alkoxides concentrations against zinc corrosion in 0.5 M HCl solution are examined. Prepared samples are characterized by FTIR and TGA. It was shown that the presence of the modifiers, either Ti or Al, facilitates the formation of the network structure and increases slightly the thermal stability of sol–gel materials. SEM and TEM show that morphology is smooth and uniform by using low modifiers concentrations, while surface deterioration appears at higher concentrations. Gravimetric measurement, polarization and EIS show that the protection ability of GPTMS-VTMS sol–gel is increased by being modified with low concentrations of Ti and Al moities. Protection efficiency value is 69.2% for unmodified film and increased to 96.2 and 95.8% by using 0.005 M of Ti and Al modifiers, respectively. This improvement is caused by both the non-permeable nature of the sol–gel coating and the enhanced structure of the sol–gel by the presence of Ti and Al modifiers. On the other hand, it is found that further increase of the modifier content allows high chance for galvanic corrosion that resulted in a decrease in protection efficiency values.

  7. Multiple corrosion protection systems for reinforced concrete bridge components.

    Science.gov (United States)

    2007-07-01

    Eleven systems combining epoxy-coated reinforcement with another corrosion protection system are evaluated using : the rapid macrocell, Southern Exposure, cracked beam, and linear polarization resistance tests. The systems include : bars that are pre...

  8. Effect of molybdate on phosphating of Nd-Fe-B magnets for corrosion protection

    OpenAIRE

    Saliba-Silva, Adonis Marcelo; Oliveira, Mara Cristina Lopes de; Costa, Isolda

    2005-01-01

    Nd-Fe-B magnets are highly susceptible to corrosion and need protection against environment attack. The use of organic coatings is one of the main methods of corrosion protection of these materials. Data related to the effect of conversion coatings, such as phosphating, on corrosion performance of these magnets is still scarce. Studies about the effect of phosphating on the corrosion resistance of a commercial Nd-Fe-B sintered magnet indicated that it increases the corrosion resistance of the...

  9. POLYETHERSULFONE COATING FOR MITIGATING CORROSION OF STEEL IN GEOTHERMAL ENVIRONMENT.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA, T.

    2005-06-01

    Emphasis was directed toward evaluating the usefulness of a polyethersulfone (PES)-dissolved N-methyl pyrrolidone (NMP) solvent precursor as a low-temperature film-forming anti-corrosion coating for carbon steel in simulated geothermal environments at brine temperatures up to 300 C. A {approx} 75 {micro}m thick PES coating performed well in protecting the steel against corrosion in brine at 200 C. However, at {>=} 250 C, the PES underwent severe hydrothermal oxidation that caused the cleavage of sulfone- and ether-linkages, and the opening of phenyl rings. These, in turn, led to sulfone {yields} benzosulfonic acid and ether {yields} benzophenol-type oxidation derivative transformations, and the formation of carbonyl-attached open rings, thereby resulting in the incorporation of the functional groups, hydroxyl and carbonyl, into the coating. The presence of these functional groups raised concerns about the diminutions in water-shedding and water-repellent properties that are important properties of the anti-corrosion coatings; such changes were reflected in an enhancement of the magnitude of susceptibility of the coatings surfaces to moisture. Consequently, the disintegration of the PES structure by hydrothermal oxidation was detrimental to the maximum efficacy of the coating in protecting the steel against corrosion, allowing the corrosive electrolytes to infiltrate easily through it.

  10. Fabrication of FDTS-modified PDMS-ZnO nanocomposite hydrophobic coating with anti-fouling capability for corrosion protection of Q235 steel.

    Science.gov (United States)

    Arukalam, Innocent O; Oguzie, Emeka E; Li, Ying

    2016-12-15

    Perfluorodecyltrichlorosilane-based poly(dimethylsiloxane)-ZnO (FDTS-based PDMS-ZnO) nanocomposite coating with anti-corrosion and anti-fouling capabilities has been prepared using a one-step fabrication technique. XPS analysis and contact angle measurements showed the fluorine content to increase, while the hydrophobicity of the coatings decreased with addition of FDTS. XRD analysis revealed existence of ZnO nanoparticles of dimensions ranging from 11.45 to 93.01nm on the surface of coatings, with the mean particle size decreasing with FDTS addition, and was confirmed by SEM and TEM observations. Interestingly, the anti-corrosion performance and mechanical properties of the coatings increased remarkably on addition of FDTS. Indeed, the observed low adhesion strength, surface energies and the outstanding anti-corrosive properties imply that the obtained coating would be useful in anti-fouling applications. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Microencapsulation of Self Healing Agents for Corrosion Control Coatings

    Science.gov (United States)

    Jolley, S. T.; Li, W.; Buhrow, J. W.; Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, is a very costly problem that has a major impact on the global economy. Results from a 2-year breakthrough study released in 2002 by the U.S. Federal Highway Administration (FHWA) showed that the total annual estimated direct cost associated with metallic corrosion in nearly every U.S. industry sector was a staggering $276 billion, approximately 3.1% of the nation's Gross Domestic Product (GOP). Corrosion protective coatings are widely used to protect metallic structures from the detrimental effects of corrosion but their effectiveness can be seriously compromised by mechanical damage, such as a scratch, that exposes the metallic substrate. The incorporation of a self healing mechanism into a corrosion control coating would have the potential to significantly increase its effectiveness and useful lifetime. This paper describes work performed to incorporate a number of microcapsule-based self healing systems into corrosion control coatings. The work includes the preparation and evaluation of self-healing systems based on curable epoxy, acrylate, and siloxane resins, as well as, microencapsulated systems based on passive, solvent born, healing agent delivery. The synthesis and optimization of microcapsule-based self healing systems for thin coating (less than 100 micron) will be presented.

  12. Localized Corrosion of Chromium Coated Steel

    NARCIS (Netherlands)

    Zhang, X.; Beentjes, P.; Mol, A.; Terryn, H.

    2006-01-01

    In this paper, we report on the studies of the local corrosion behaviour of chromium-coated ultra low carbon steel in NaCl solution using polarization, electrochemical impedance spectroscopy (EIS) and SVET.

  13. Corrosion Resistance of Zinc Coatings With Aluminium Additive

    Directory of Open Access Journals (Sweden)

    Votava Jiří

    2014-08-01

    Full Text Available This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test. Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

  14. Analysis of electrochemical noise data in both time and frequency domains to evaluate the effect of ZnO nanopowder addition on the corrosion protection performance of epoxy coatings

    Directory of Open Access Journals (Sweden)

    H. Ashassi-Sorkhabi

    2016-11-01

    Full Text Available Epoxy–ZnO nanocomposite coatings have been developed for corrosion protection of steel. Structural characterization of the prepared nanocomposites was performed using scanning electron microscopy (SEM. The anti-corrosive properties of the coatings were evaluated by electrochemical noise (EN. On the basis of the EN results in both time and frequency domains, the nanocomposite material with low ZnO concentration (0.1% wt.% was found to be much superior in corrosion protection when tested in aqueous NaCl electrolyte. Finally, EIS measurements were carried out and the data fitted with suitable equivalent circuit. Resistance parameters obtained by both techniques were found to be in relatively good agreement.

  15. Smart Multifunctional Coatings for Corrosion Detection and Control in the Aerospace Industry

    Science.gov (United States)

    Calle, Luz Marina

    2015-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  16. Replacement of chromates in paints and corrosion protection systems [Stage 2

    Science.gov (United States)

    2004-05-01

    This technical report presents the second stage results of a multi-year project to develop chromate-free paints and corrosion protection systems. Chromate-containing coatings and paints are very effective in providing corrosion resistance and are wid...

  17. Replacement of chromates in paints and corrosion protection systems [Stage 1

    Science.gov (United States)

    2004-05-01

    This technical report presents the first stage results of a multi-year project to develop chromate-free paints and corrosion protection systems. Chromate coatings and chromate-containing paints are very effective in providing corrosion resistance and...

  18. Corrosion Protection of Aluminum

    Science.gov (United States)

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  19. NANOSCALE BOEHMITE FILLER FOR CORROSION AND WEAR RESISTANT POLYPHENYLENESULFIDE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2003-06-26

    The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.

  20. Electroless Deposition of Ni-Cu-P Coatings Containing Nano-Al2O3 Particles and Study of Its Corrosion Protective Behaviour in 0.5 M H2SO4

    Directory of Open Access Journals (Sweden)

    H. Ashassi-Sorkhabi

    2014-01-01

    Full Text Available Ni-Cu-P/nano-Al2O3 composite coatings are prepared on mild steel from an alkaline electroless plating bath containing different concentrations of Al2O3 nanoparticles. The protective effect of codeposited nanoparticles on the corrosion behaviour of the coatings is studied in 0.5 M H2SO4 solution. The electrochemical methods, that is, electrochemical noise (ECN, electrochemical impedance spectroscopy (EIS, and polarization measurements, are used to characterize the corrosion properties of the coatings. The results show that the inclusion of nanosized particles leads to significant improvement of corrosion resistance of the coatings. The highest corrosion resistance is obtained at 20 ppm of nanoparticles concentration in the plating bath. The ECN measurements results are in good agreement with results obtained from two other electrochemical methods after trend removal. The SEM images prove that nano-Al2O3 particles were embedded in the Ni-Cu-P matrix and are dispersed uniformly on the coating surface.

  1. Poly (3,4-ethylenedioxythiophene) graphene oxide composite coatings for controlling magnesium implant corrosion.

    Science.gov (United States)

    Catt, Kasey; Li, Huaxiu; Cui, X Tracy

    2017-01-15

    Magnesium (Mg) is a promising biodegradable implant material because of its appropriate mechanical properties and safe degradation products. However, in vivo corrosion speed and hydrogen gas production need to be controlled for uses in biomedical applications. Here we report the development of a conducting polymer 3,4-ethylenedioxythiphene (PEDOT) and graphene oxide (GO) composite coating as a corrosion control layer. PEDOT/GO was electropolymerized on Mg samples in ethanol media. The coated Mg samples were subjected to various corrosion tests. The PEDOT/GO coating significantly reduced the rate of corrosion as evidenced by lower Mg ion concentration and pH of the corrosion media. In addition, the coating decreased the evolved hydrogen. Electrochemical analysis of the corroding samples showed more positive corrosion potential, a decreased corrosion current, and an increase in the polarization resistance. PEDOT/GO corrosion protection is attributed to three factors; an initial passive layer preventing solution ingress, buildup of negative charges in the film, and formation of corrosion protective Mg phosphate layer through redox coupling with Mg corrosion. To explore the biocompatibility of the coated implants in vitro, corrosion media from PEDOT/GO coated or uncoated Mg samples were exposed to cultured neurons where PEDOT/GO coated samples showed decreased toxicity. These results suggest that PEDOT/GO coating will be an effective treatment for controlling corrosion of Mg based medical implants. Coating Mg substrates with a PEDOT/GO composite coating showed a significant decrease in corrosion rate. While conducting polymer coatings have been used to prevent corrosion on various metals, there has been little work on the use of these coatings for Mg. Additionally, to our knowledge, there has not been a report of the combined used of conducting polymer and GO as a corrosion control layer. Corrosion control is attributed to an initial barrier layer followed by

  2. Development of novel protective high temperature coatings on heat exchanger steels and their corrosion resistance in simulated coal firing environment; Developpement de revetements pour les aciers d'echangeurs thermiques et amelioration de leur resistance a la corrosion en environnement simulant les fumees de combustion et de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Rohr, V.

    2005-10-15

    Improving the efficiencies of thermal power plants requires an increase of the operating temperatures and thus of the corrosion resistance of heat exchanger materials. Therefore, the present study aimed at developing protective coatings using the pack cementation process. Two types of heat exchanger steels were investigated: a 17% Cr-13% Ni austenitic steel and three ferritic-martensitic steels with 9 (P91 and P92) and 12% Cr (HCM12A). The austenitic steel was successfully aluminized at 950 C. For the ferritic-martensitic steels, the pack cementation temperature was decreased down to 650 C, in order to maintain their initial microstructure. Two types of aluminides, made of Fe{sub 2}Al{sub 5} and FeAl, were developed. A mechanism of the coating formation at low temperature is proposed. Furthermore, combining the pack cementation with the conventional heat treatment of P91 allowed to take benefit of higher temperatures for the deposition of a two-step Cr+Al coating. The corrosion resistance of coated and uncoated steels is compared in simulated coal firing environment for durations up to 2000 h between 650 and 700 C. It is shown that the coatings offer a significant corrosion protection and, thus, an increase of the component lifetime. Finally, the performance of coated 9-12% Cr steels is no longer limited by corrosion but by interdiffusion between the coating and the substrate. (author)

  3. The corrosion protection of aluminum by various anodizing treatments

    Science.gov (United States)

    Danford, Merlin D.

    1989-01-01

    Corrosion protection to 6061-T6 aluminum, afforded by both teflon-impregnated anodized coats (Polylube and Tufram) and hard-anodized coats (water sealed and dichromate sealed), was studied at both pH 5.5 and pH 9.5, with an exposure period of 28 days in 3.5 percent NaCl solution (25 C) for each specimen. In general, corrosion protection for all specimens was better at pH 9.5 than at pH 5.5. Protection by a Tufram coat proved superior to that afforded by Polylube at each pH, with corrosion protection by the hard-anodized, water-sealed coat at pH 9.5 providing the best protection. Electrochemical work in each case was corroborated by microscopic examination of the coats after exposure. Corrosion protection by Tufram at pH 9.5 was most comparable to that of the hard-anodized samples, although pitting and some cracking of the coat did occur.

  4. The use of electrochemical measurement techniques towards quality control and optimisation of corrosion properties of thermal spray coatings

    NARCIS (Netherlands)

    Vreijling, M.P.W.; Hofman, R.; Westing, E.P.M. van; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    Metal spray coatings are ever more recognised as a possible superior means of corrosion protection in many environments. Extended service life combined with little or no maintenance provides interesting opportunities for both environmentalists and corrosion engineers. Although many successful

  5. Materials corrosion and protection from first principles

    Science.gov (United States)

    Johnson, Donald F.

    Materials erode under environmental stresses such as high temperature, high pressure, and mechanical shock/stress, but erosion is often exacerbated by chemical corrosion. In this dissertation, periodic density functional theory (DFT) is employed to simulate interfacial adhesion, absorption kinetics, bulk diffusion, and other material phenomena (e.g., hydrogen-enhanced decohesion and shock-induced phase changes) with the intention of understanding corrosion and subsequent failure processes and guiding the design of new protective coatings. This work examines corrosion and/or protection of materials ( i.e., Fe, Ni, W) with important applications: structural steel, gun tubes, high-pressure oil recovery vessels, jet engine turbine blades, and fusion reactor walls. We use DFT to model the pressure-induced, bcc-to-hcp phase transformation in Fe, in which a new low energy pathway is predicted exhibiting nonadiabatic behavior coupling magnetic and structural changes. Protection of steel is addressed in two aspects: interfacial adhesion of protective coatings and assessment of corrosion resistance provided by a surface alloy. First, the current chrome-coated steel system is examined where extremely strong adhesion is predicted at the Cr/Fe interface originating in strong spin correlations. A ceramic coating, SiC, is considered as a possible replacement for Cr. Strong adhesion is predicted, especially for C-Fe interfacial bonds. To assess corrosion resistance, we model ingress of two common corrosive elements, H and C, into two Fe alloys, FeAl and Fe3Si. Adsorption and absorption thermodynamics and kinetics, as well as bulk dissolution and diffusion are calculated in order to determine whether these two alloys can inhibit uptake of H and C. Relative to pure Fe, dissolved H and C are less stable in the alloys, as the dissolution enthalpy is predicted to be more endothermic. Overall, the energy barriers and rate constants for adsorbed H/C diffusing into Fe3Si subsurface layers

  6. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-08-31

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

  7. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  8. Corrosion protection for silver reflectors

    Science.gov (United States)

    Arendt, Paul N.; Scott, Marion L.

    1991-12-31

    A method of protecting silver reflectors from damage caused by contact with gaseous substances which are often present in the atmosphere and a silver reflector which is so protected. The inventive method comprises at least partially coating a reflector with a metal oxide such as aluminum oxide to a thickness of 15 .ANG. or less.

  9. 49 CFR 193.2625 - Corrosion protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or reliability...

  10. Poly(aniline) in corrosion resistant coatings

    Energy Technology Data Exchange (ETDEWEB)

    McAndrew, T.P.; Miller, S.A.; Gilicinski, A.G.; Robeson, L.M. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1996-10-01

    During the past two decades, one of the most active fields of solid-state science has been electrically conductive polymers. These are polymers which are insulators as prepared, but which can be converted to polymers having many or all the properties of a metal, by virtue of appropriate chemical/electrochemical oxidation or reduction. Typically, applications examined for electrically conductive polymers have been in areas such as rechargeable batteries and charge dissipative coatings. Recently it has been reported that poly(aniline), in its electrically conductive, protonated form, shows excellent performance as a coating for preventing the corrosion of carbon steel. The present research has shown that in fact, the non-conductive, unprotonated form of poly(aniline) shows even better performance in corrosion prevention than the conductive form. Moreover, it has been shown that poly(aniline) can be blended with other polymers to improve their corrosion resistance performance (e.g., polyimides), or used as a hardener for epoxides or diisocyanates, to give very good corrosion resistant coatings. Poly(aniline) performance is explained in terms of its ability to form dense, adherent films, and create a basic surface on carbon steel surfaces.

  11. Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

    Science.gov (United States)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

    This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

  12. Practical Implications of the Use of Aluminide Coatings for the Corrosion Protection of Superalloys in Gas Turbines

    Science.gov (United States)

    1984-04-01

    m’ i i i i i ni 3 _ NONCOATED { AIR • ALUMINIOE COATEDMHALFORD & NACHTIGALL)(49| NONCOATED ) VACUUM • ALUM.N.DE COATED^ iK0Rro^ZmKWm i...Ftg. 22 - Tharmsl fattgu* propartm of potycryilsHina and UOS iupar«lk>vt in tha •nd non-coatod cooditioo. 1 r O NONCOATED ALUMINIOE 600 800

  13. Corrosion-Resistant Acrylic Coatings

    Science.gov (United States)

    1992-03-31

    amount of a corrosion-inhibiting pigment system consisting essentially of critical amounts of at least one zinc phosphate , zinc molybdate and at least... phosphate , zinc , moiybdate and at least one zinc salt of a benzoic acid. 15 Claims, No Drawings 5,100,942 1 2 moDAcinv DrcicT.vT . -™v...8217VT’ T Z^ doned ’ by weight of at leas« one zinc phosphate , 40 «o 260 pans by weigh» of zinc molybdate, and 1 to 30 pans by BACKGROUND OF THE

  14. Corrosion-Resistant Alkyd Coatings

    Science.gov (United States)

    1992-02-18

    a corrosion-inhibiting pigment consisting essentially of critical amounts of at least one zinc phosphate , zinc molybdate and at least one zinc salt...of at leajt one 2inc phosphate , continuationi of application 07/211.026 filed June 16, 40 to 260 pans by weight cf zinc molybdate. and 1 to 30 1988... phosphate , zinc molybdate and a. tions of this invention, however, are resistant to harsh lea$t one zmc »•« of a benzoic acid. weather conditions and

  15. Effective modern methods of protecting metal road structures from corrosion

    Science.gov (United States)

    Panteleeva, Margarita

    2017-10-01

    In the article the ways of protection of barrier road constructions from various external influences which cause development of irreversible corrosion processes are considered. The author studied modern methods of action on metal for corrosion protection and chose the most effective of them: a method of directly affecting the metal structures themselves. This method was studied in more detail in the framework of the experiment. As a result, the article describes the experiment of using a three-layer polymer coating, which includes a thermally activated primer, an elastomeric thermoplastic layer with a spatial structure, and a strong outer polyolefin layer. As a result of the experiment, the ratios of the ingredients for obtaining samples of the treated metal having the best parameters of corrosion resistance, elasticity, and strength were revealed. The author constructed a regression equation describing the main properties of the protective polymer coating using the simplex-lattice planning method in the composition-property diagrams.

  16. Study On Protective Coatings To Steel Rebars | Mohammed ...

    African Journals Online (AJOL)

    Chemical resistance test and Impressed voltage test conducted on coated specimens revealed that, Inhibited cement slurry coating and Cement polymer composite coating possesses the necessary corrosion resistance properties as per IS and ASTM. Although Galvanization offers excellent sacrificial protection to steel ...

  17. Monitoring Cathodic Shielding and Corrosion under Disbonded Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Varela, F.; Tan, M. Y. J.; Hinton, B.; Forsyth, M. [Deakin University, Victoria (Australia)

    2017-06-15

    Monitoring of corrosion is in most cases based on simulation of environmental conditions on a large and complex structure such as a buried pipeline using a small probe, and the measurement of thermodynamics and kinetics of corrosion processes occurring on the probe surface. This paper presents a hybrid corrosion monitoring probe designed for simulating deteriorating conditions wrought by disbonded coatings and for measuring current densities and distribution of such densities on a simulated pipeline surface. The concept of the probe was experimentally evaluated using immersion tests under cathodic protection (CP) in high resistivity aqueous solution. Underneath the disbonded area, anodic currents and cathodic currents were carefully measured. Anodic current densities were used to calculate metal loss according to Faraday’s law. Calculated corrosion patterns were compared with corrosion damage observed at the surface of the probe after a series of stringent tests. The capability of the probe to measure anodic current densities under CP, without requiring interruption, was demonstrated in high resistivity aqueous solution. The pattern of calculated metal loss correlated well with corrosion products distribution observed at the array surface. Working principles of the probe are explained in terms of electrochemistry.

  18. Pitting corrosion protection of low nickel stainless steel by ...

    Indian Academy of Sciences (India)

    Pitting corrosion protection of low nickel stainless steel by electropolymerized conducting polymer coating in 0·5 M NaCl solution. T DHANABAL, G AMIRTHAGANESAN. ∗ and J RAVICHANDRAN. Post Graduate and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science,.

  19. Corrosion protection of aluminum alloys in contact with other metals

    Science.gov (United States)

    Kuster, C. A.

    1969-01-01

    Study establishes the quality of chemical and galvanized protection afforded by anodized and aldozided coatings applied to test panels of various aluminum alloys. The test panels, placed in firm contact with panels of titanium alloys, were subjected to salt spray tests and visually examined for corrosion effect.

  20. High-temperature corrosion resistance of ceramics and ceramic coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.

    1996-06-01

    Ceramics and ceramic composites offer the potential to operate fossil energy systems at the higher temperatures necessary for improved energy efficiency and better environmental control. However, because many fossil fuel-derived processes contain sulfur, chlorine, and carbon, as well as oxygen, degradation from high-temperature corrosion and environmental effects arising from reactions of solids with gases and condensable products is a common life-determining factor in operating systems. Ceramic-based products are not immune to such degradation; adequate corrosion resistance must be assured to exploit the technical and economic potential of such materials. This is normally accomplished by using stable, sound oxides that exist in their bulk form, that naturally grow as surface layers upon exposure to an oxidizing environment, or that are deposited as a coating on a susceptible material. It is therefore important to examine the critical issues with respect to more environmental stability of ceramics that have the potential to be corrosion resistant in particular fossil environments. Key aspects include not only chemical compatibility, but the influence of the environment on the mechanical behavior of the ceramic materials. In addition, for coatings, the mechanical reliability of the ceramic is a key issue in that an otherwise corrosion-resistant surface layer must remain sound and adherent in order to provide protection to the underlying substrate. The purpose of this work is to support the development of advanced ceramics and ceramic composites for applications in fossil environments by examining critical issues related to high-temperature corrosion resistance. More specifically, the overall objective of this task is to examine the chemical compatibility and reliability of potentially corrosion-resistant ceramics being developed as protective overcoats and/or structural materials as parts of other work elements funded by the AR&TD Program.

  1. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    DEFF Research Database (Denmark)

    Cecchetto, L; Ambat, Rajan; Davenport, A.J.

    2007-01-01

    AA5182 aluminium alloy cold rolled samples were coated by thin Wlms of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very eVective for corrosion protection of aluminium alloys in neutral environment. This study underlines...

  2. Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings

    NARCIS (Netherlands)

    Hofman, R.; Vreijling, M.P.W.; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to

  3. Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmi, R.V. [Surface Engineering Division, Council of Scientific and Industrial Research – National Aerospace Laboratories, HAL Airport Road, Kodihalli, Bengaluru 560017 (India); Aruna, S.T., E-mail: staruna194@gmail.com [Surface Engineering Division, Council of Scientific and Industrial Research – National Aerospace Laboratories, HAL Airport Road, Kodihalli, Bengaluru 560017 (India); Sampath, S. [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bengaluru 560012 (India)

    2017-01-30

    Highlights: • Corrosion protection efficiency comparison of ceria nanoparticles and cerium nitrate. • Silica-alumina hybrid coating exhibited good barrier protection. • Detailed XPS study confirm the hybrid structure and presence of Ce species in coating. • Loss of cerium ions not prevalent in ceria doped coating unlike that of cerium nitrate. • Ceria increased the coating integrity, corrosion inhibition and barrier protection. - Abstract: The present work provides a comparative study on the corrosion protection efficiency of defect free sol-gel hybrid coating containing ceria nanoparticles and cerium nitrate ions as corrosion inhibitors. Less explored organically modified alumina-silica hybrid sol-gel coatings are synthesized from 3-glycidoxypropyltrimethoxysilane and aluminium-tri-sec-butoxide. The microemulsion derived nanoparticles and the hybrid coatings are characterized and compared with coatings containing cerium nitrate. Corrosion inhibiting capability is assessed using electrochemical impedance spectroscopy. Scanning Kelvin probe measurements are also conducted on the coatings for identifying the apparent corrosion prone regions. Detailed X-ray photoelectron spectroscopy (XPS) analysis is carried out to comprehend the bonding and corrosion protection rendered by the hybrid coatings.

  4. Structure and corrosion properties of PVD Cr-N coatings

    CERN Document Server

    Liu, C; Ziegele, H; Leyland, A; Matthews, A

    2002-01-01

    PVD Cr-N coatings produced by physical vapor deposition (PVD) are increasingly used for mechanical and tribological applications in various industrial sectors. These coatings are particularly attractive for their excellent corrosion resistance, which further enhances the lifetime and service quality of coated components. PVD Cr-N coated steels in an aqueous solution are usually corroded by galvanic attack via through-coating 'permeable' defects (e.g., pores). Therefore, the corrosion performance of Cr-N coated steel is determined by a number of variables of the coating properties and corrosive environment. These variables include: (i) surface continuity and uniformity; (ii) through-coating porosity; (iii) film density and chemical stability; (iv) growth stresses; (v) interfacial and intermediate layers; (vi) coating thickness; (vii) coating composition; and (viii) substrate properties. In this article, PVD Cr-N coatings were prepared, by electron-beam PVD and sputter deposition, with different compositions, t...

  5. Tailored Aluminium based Coatings for Optical Appearance and Corrosion Resistance

    DEFF Research Database (Denmark)

    Aggerbeck, Martin

    potential differences in the microstructure, and protection from the network of the Al3Ti phases precipitated during the heat treatment. Laser surface cladding of aluminium containing up to 20 wt. % Ti6Al4V were studied focusing on the microstructure and the alkaline corrosion properties. Due......The current project investigated the possibility of designing aluminium based coatings focusing on the effect of composition and surface finish on the optical appearance and on the alkaline corrosion properties using titanium as the main alloying element. The main results and discussions...... with aluminium. Unfortunately, aluminium corrodes heavily in the alkaline environments known e.g. from a brush less car wash (> pH 12). Today nickel salt sealing is used to protect e.g. aluminium wheel rims, but an alternative is needed due to environmental and health reasons. Investigations using the previously...

  6. Corrosion and protections of Somaloy® components

    OpenAIRE

    Yu, ZHAO

    2016-01-01

    Corrosion protection is very significant for metals in modern society from the view of industrial development. This thesis work project involves a research study that is aimed to investigate the effect of corrosion on the mechanical strength and magnetic properties of four no treated or treated Somaloy® component samples (Somaloy®700 1P,  Somaloy®700 3P, Somaloy®700HR 5P and Somaloy®110i 5P) provided by Höganäs AB and laminated steel sheets by salt spray test. The coatings for protection are ...

  7. Environmentally Friendly Coating Technology for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.; Jolley, Scott T.; Pearman, Benjamin P.; Zhang, Xuejun; Fitzpatrick, Lilliana; Gillis, Mathew; Blanton, Michael; hide

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry.

  8. Multi-functional hybrid coatings containing silica nanoparticles and anti-corrosive acrylate monomer for scratch and corrosion resistance.

    Science.gov (United States)

    Seo, Ji Yeon; Han, Mijeong

    2011-01-14

    Multi-functional hybrid coatings having both anti-corrosion and scratch resistance were prepared from modified silica nanoparticles and functional acrylates. To improve the dispersion properties of silica nanoparticles in the organic/inorganic hybrid coatings, the surface of the nanoparticles was modified with γ-methacryloxypropyltrimethoxysilane. The coating solution could be prepared by mixing modified silica nanoparticles, tetrasiloxane acrylate, di-acrylate monomer containing an anti-corrosion functional group, acrylic acid, and an initiator in a solvent. The mixture was then dip-coated on iron substrates and finally polymerized by ultraviolet (UV) irradiation. Corrosion and scratch resistance of the coated iron was evaluated by electrochemical impedance spectroscopy (EIS) and a pencil hardness test, respectively. From the EIS results, the coatings with tetrasiloxane acrylate and di-acrylate did not show any decrease in impedance or phase angle, even after 50 days' exposure to 0.1 M NaCl electrolyte, whereas the conventional acrylate coatings started to fail after only 24 h. A hybrid coating containing the amine-quinone functional group exhibited excellent corrosion protection properties with 4-5H pencil hardness.

  9. Structure and corrosion properties of Cr coating deposited on aerospace bearing steel

    Science.gov (United States)

    Wang, Fangfang; Zhang, Fengxiang; Zheng, Lijing; Zhang, Hu

    2017-11-01

    The corrosion protection of chromium coating deposited on aerospace bearing steels by using the Filtered Cathodic Vacuum Arc deposition- Metal Evaporation Vacuum Arc duplex technique (MEVVA-FCVA) had been investigated. The protection efficiency of chromium coating on different substrate materials had also been evaluated. The chromium coating was mainly composed of nanocrystallineα-Cr in a range of 50-200 nm. The orientation distributions of α-Cr film on substrates with different composition had a certain difference to each other. Electrochemical experimental results indicated that the chromium coating significantly improved the corrosion resistance of experimental bearing steels in 3.5% NaCl solution. The protective efficiency of chromium films were all over 98%. The corrosion resistance of chromium coating was influenced by the chemical composition of substrate material. The chromium coatings on higher Cr-containing substrate displayed lower corrosion current density and more positive corrosion potential. The increase of passive film thickness and the formation of a mass of chromium oxide and hydroxide on the surface are responsible for the improved corrosion properties.

  10. Graphene Nanoplatelets Based Protective and Functionalizing Coating for Stainless Steel.

    Science.gov (United States)

    Mondal, Jayanta; Kozlova, Jekaterina; Sammelselg, Väino

    2015-09-01

    Stainless steel is the most widely used alloy for many industrial and everyday applications, and protection of this alloy substrate against corrosion is an important industrial issue. Here we report a promising application of graphene oxide and graphene nanoplatelets as effective corrosion inhibitors for AISI type 304 stainless steel alloy. The graphene oxide and graphene coatings on the stainless steel substrates were prepared using spin coating techniques. Homogeneous and complete surface coverage by the graphene oxide and graphene nanoplatelets were observed with a high-resolution scanning electron microscope. The corrosion inhibition ability of these materials was investigated through measurement of open circuit potential and followed by potentiodymamic polarization analysis in aqueous sodium chloride solution before and after a month of immersion. Analyzed result exhibits effective corrosion inhibition for both substrates coated with graphene oxide or graphene nanoplatelets by increasing corrosion potential, pitting potential and decreasing passive current density. The corrosion inhibition ability of the coated substrates has not changed even after the long-term immersion. The result showed both graphene materials can be used as an effective corrosion inhibitor for the stainless steel substrates, which would certainly increase lifetime the substrate. However, long-term protection ability of the graphene coated susbtsrate showed somewhat better inhibition performance than the ones coated with graphene oxide.

  11. Corrosion Prevention of Aluminum Nanoparticles by a Polyurethane Coating.

    Science.gov (United States)

    Nishimura, Toshiyasu; Raman, Vedarajan

    2014-06-19

    In order to prevent corrosion, aluminum nanoparticles were coated with a polyurethane polymer. The coverage of the polyurethane polymer was controlled from 0 to 100%, which changed the corrosion rate of the nanoparticles quantitatively. The surface of the polymer coating was investigated by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM), and the corrosion resistance of the nanoparticles was estimated by a wet/dry corrosion test on a Pt plate with a NaCl solution. From a TEM with EDAX analysis, the 10 mass% polymer coated Al particles in the synthesis were almost 100% covered on the surface by a polymer film of 10 nm thick. On the other hand, the 3 mass% polymer coated Al was almost 40% covered by a film. In the AFM, the potential around the Al particles had a relatively low value with the polymer coating, which indicated that the conductivity of the Al was isolated from the Pt plate by the polymer. Both the corrosion and H₂ evolution reaction rates were quantitatively reduced by the mass% of polymer coating. In the case of the 10 mass% coated sample, there was no corrosion of Al nanoparticles. This fact suggested that the electrochemical reaction was suppressed by the polymer coating. Moreover, the reaction rate of Al nanoparticles was suppressed in proportion to the coverage percentage of the coating. Thus, to conclude, it was found that the corrosion rate of Al nanoparticles could be quantitatively suppressed by the coverage percentage of the polymer coating.

  12. Corrosion Prevention of Aluminum Nanoparticles by a Polyurethane Coating

    Directory of Open Access Journals (Sweden)

    Toshiyasu Nishimura

    2014-06-01

    Full Text Available In order to prevent corrosion, aluminum nanoparticles were coated with a polyurethane polymer. The coverage of the polyurethane polymer was controlled from 0 to 100%, which changed the corrosion rate of the nanoparticles quantitatively. The surface of the polymer coating was investigated by Transmission Electron Microscopy (TEM and Atomic Force Microscopy (AFM, and the corrosion resistance of the nanoparticles was estimated by a wet/dry corrosion test on a Pt plate with a NaCl solution. From a TEM with EDAX analysis, the 10 mass% polymer coated Al particles in the synthesis were almost 100% covered on the surface by a polymer film of 10 nm thick. On the other hand, the 3 mass% polymer coated Al was almost 40% covered by a film. In the AFM, the potential around the Al particles had a relatively low value with the polymer coating, which indicated that the conductivity of the Al was isolated from the Pt plate by the polymer. Both the corrosion and H2 evolution reaction rates were quantitatively reduced by the mass% of polymer coating. In the case of the 10 mass% coated sample, there was no corrosion of Al nanoparticles. This fact suggested that the electrochemical reaction was suppressed by the polymer coating. Moreover, the reaction rate of Al nanoparticles was suppressed in proportion to the coverage percentage of the coating. Thus, to conclude, it was found that the corrosion rate of Al nanoparticles could be quantitatively suppressed by the coverage percentage of the polymer coating.

  13. Morphology and corrosion resistance of Zn-Co and Zn-Co-Fe alloy coatings

    NARCIS (Netherlands)

    Lodhi, Z.F.; Mol, L.M.C.; Hovestad, A.; Terryn, H.; Wit, J.H.W. de

    2008-01-01

    Cadmium (Cd) has been extensively used as an excellent corrosion protective coating for steel applications in aerospace, automotive, electrical and fasteners industries. However, Cd is banned due to its toxic nature and strict environmental regulations. In this study, the coating morphology and

  14. Nanocontainer-Enhanced Self-Healing for Corrosion-Resistant Ni Coating on Mg Alloy.

    Science.gov (United States)

    Xie, Zhi-Hui; Li, Dan; Skeete, Zakiya; Sharma, Anju; Zhong, Chuan-Jian

    2017-10-18

    The ability to manipulate the functionalization of Ni coating is of great importance in improving the corrosion resistance of magnesium (Mg) alloy for many industrial applications. In the present work, MCM-41 type mesoporous silica nanocontainers (MSNs) loaded with corrosion inhibitor (NaF) were synthesized and employed as smart reinforcements to enhance the integrity and corrosion inhibition of the Ni coating. The incorporation of the F-loaded MSNs (F@MSNs) to enhance the corrosion resistant capacity of a metallic coating is reported for the first time. The mesoporous structures of the as-prepared MSNs and F@MSNs were confirmed by transmission electron microscopy (TEM), small angle X-rays scattering (SAXS), and N 2 adsorption-desorption isotherms. The X-ray photoelectron spectroscopy (XPS) data demonstrated the successful immobilization of fluoride ion on the MSNs and formation of a magnesium fluoride (MgF 2 ) protective film at the corrosion sites of the Mg alloy upon soaking in a F@MSNs-containing NaCl solution. The results from potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) for both bare Mg alloy and Ni coatings with and without F@MSNs have revealed a clear decrease in corrosion rate in a corrosive solution for a long-time immersion due to the introduction of F@MSNs. These findings open new opportunities in the exploration of self-healing metallic coatings for highly enhanced anticorrosion protection of Mg alloy.

  15. PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications

    Science.gov (United States)

    Li, Wenyan; Calle, Luz M.

    2008-01-01

    Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

  16. Corrosion resistance and biocompatibility of SrHAp/ZnO composite implant coating on titanium

    Science.gov (United States)

    Huang, Yong; Zeng, Hongjuan; Wang, Xuexin; Wang, Deshun

    2014-01-01

    The corrosion resistance of electrodeposited ZnO containing and strontium doped hydroxyapatite (SrHAp/ZnO) coating on titanium (Ti) substrate was investigated. The microstructure, phase composition and corrosion resistance of the coating were studied. The results reveal that Sr2+ and ZnO incorporation markedly increased the density of HAp coating, i.e. the fabricated coating had significantly lower porosity than the original HAp coating. The SrHAp/ZnO coating was dense and uniform, with a flocculent morphological structure of apatite. The SrHAp/ZnO crystals were carbonated calcium-deficient hydroxyapatite, and Sr2+ and ZnO were homogeneously distributed in the coating. The thickness of the composite coating was almost 10 μm without delamination or cracks at the interface. Bond strength test revealed that the adhesion of the SrHAp/ZnO coating was more enhanced than that of the HAp coating. The SrHAp/ZnO-coated Ti had a lower corrosion rate than the pure HAp-coated sample, which suggests the protective characteristic of the composite coating. Osteoblast cellular tests demonstrated that the SrHAp/ZnO composite coating greatly enhanced the in vitro biocompatibility of the Ti substrate.

  17. Emeraldine base as corrosion protective layer on aluminium alloy AA5182, effect of the surface microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Cecchetto, L. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France); Ambat, R. [School of Engineering Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Davenport, A.J. [School of Engineering Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Delabouglise, D. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France)]. E-mail: Didier.Delabouglise@lepmi.inpg.fr; Petit, J.-P. [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, CNRS-UJF-INP-Grenoble (UMR 5631), ENSEEG, BP 75, 38402 St. Martin d' Heres (France); Neel, O. [Centre de Recherche de Voreppe, Pechiney, Parc economique Centr' Alp, 38340 Voreppe (France)

    2007-02-15

    AA5182 aluminium alloy cold rolled samples were coated by thin films of emeraldine base (EB) obtained from a 5% solution in N-methylpyrrolidinone. Accelerated corrosion tests prove this coating very effective for corrosion protection of aluminium alloys in neutral environment. This study underlines the prominent role of surface cathodic intermetallic particles in pit initiation and coating break down in enhanced corrosion conditions and suggest that, beside the EB barrier properties, the enhanced corrosion resistance observed on the EB coated samples could partly arise from two other mains factors:- a weak redox activity of the polymer which passivate the metal, - a proton involving self-healing process taking place at the polymer-metal interface, which contributes to delay local acidification in first steps of corrosion on EB coated aluminium surfaces.

  18. Diffusion of sulfuric acid in protective organic coatings

    DEFF Research Database (Denmark)

    Wang, Ting; Møller, Victor Buhl; Dam-Johansen, Kim

    Organic protective coatings and linings are widely used to prevent corrosion in industrial processes. However, the permeation of aggressive chemicals through coatings can induce failures. These are described in the literature, but rarely quantified. To measure the diffusion rates of aggressive...

  19. Electropolymerization of camphorsulfonic acid doped conductive polypyrrole anti-corrosive coating for 304SS bipolar plates

    Science.gov (United States)

    Jiang, Li; Syed, Junaid Ali; Gao, Yangzhi; Zhang, Qiuxiang; Zhao, Junfeng; Lu, Hongbin; Meng, Xiangkang

    2017-12-01

    Conductive polymer coating doped with large molecular organic acid is an alternative method used to protect stainless steel (SS) bipolar plates in proton exchange membrane fuel cells (PEMFCs). However, it is difficult to select the proper doping acid, which improves the corrosion resistance of the coating without affecting its conductivity. In this study, large spatial molecular group camphorsulfonic acid (CSA) doped polypyrrole (PPY) conductive coating was prepared by galvanostatic electropolymerization on 304SS. The electrochemical properties of the coating were evaluated in 0.1 M H2SO4 solution in order to simulate the PEMFC service environment. The results indicate that the coating increased the corrosion potential and shifted Ecorr towards more positive value, particularly the jcorr value of PPY-CSA coated 304SS was dropped from 97.3 to 0.00187 μA cm-2. The long-term immersion tests (660 h) show that the PPY-CSA coating exhibits better corrosion resistance in comparison with the small acid (SO42-) doped PPY-SO42- or PPY/PPY-SO42- coatings. Moreover, the PPY-CSA coating presents low contact resistance and maintains strong corrosion resistance during the prolonged exposure time due to barrier effect and anodic protection.

  20. Fabrication of Superhydrophobic Calcium Phosphate Coating on Mg-Zn-Ca alloy and Its Corrosion Resistance

    Science.gov (United States)

    Zhang, Lashuang; Jiang, Yue; Zai, Wei; Li, Guangyu; Liu, Shaocheng; Lian, Jianshe; Jiang, Zhonghao

    2017-11-01

    A novel superhydrophobic calcium phosphate coating was prepared on a magnesium alloy substrate by a highly effective chemical conversion process and subsequent chemical modification. Different methods were employed to characterize the surface morphology and chemical composition as well as measure the wettability of the coating. It was demonstrated that the as-prepared superhydrophobic calcium phosphate coating has a typical three-level hierarchical structure consisted of micro-protrusions, submicro-lumps and nano-grains, conferring excellent superhydrophobicity with a water contact angle of 159°. The electrochemical measurements and appropriate equivalent circuit revealed that the corrosion-resistant performance of the superhydrophobic calcium phosphate coating was significantly improved as compared with that of the substrate, the corrosion potential of the superhydrophobic coating increases from -1.56 to -1.36 V, and its corrosion current density decreases from 1.29 × 10-4 to 1.3 × 10-6 A/cm2. The anti-corrosion mechanism of the superhydrophobic coating was also discussed. It can be indicated that the corrosion inhibitive properties of the coating are in accordance with its hydrophobicity, which is owing to the presence of a protective layer of air trapped in the grooves of the coating surface to isolate the underlying materials from the external environment.

  1. Electromagnetic methods for corrosion under paint coating measurement

    Science.gov (United States)

    Zhang, Hong; Tian, Gui Yun; Simm, Anthony; Alamin, Mohammed

    2013-01-01

    Corrosion under coating has a serious effect on the metal conductivity and corrosion layer permittivity. A high frequency (13.56 MHz) Radio Frequency Identification (RFID) based system has been developed to measure corrosion under coating. The corrosion behaviour of coated steel has been investigated from a very fundamental understanding of permittivity using a Vector Network Analyser (VNA). This paper will first review corrosion and dielectric property measurement methods and investigate RFID tag antenna responses under different material properties of corrosion samples with atmospheric exposure times using VNA. The purpose of this study was to examine the RFID system for corrosion detection. The RFID tag's coil and VNA are employed to measure the impedance change to determine the conductivity and relative permittivity variance with different atmospheric exposure times (1 month, 3 months, 6 months, 10 months and 12 months). Different spectrum distributions under different corrosion samples are investigated. Based on the studies, VNA based system testing, phase responses from the mild steel samples with different coating thickness are measured. The experimental results show that these two introduced techniques are able to distinguish between different exposure times with coating. Based on the results, corrosion detection under coating using equivalent permittivity and conductivity are developed and evaluated. Preliminary results show that the high frequency (HF) RFID method can be extended to a new application for detection of corrosion under coating and development of HF RFID systems for corrosion monitoring. Dielectric probe is applied to measure the permittivity variance with different paint thickness. With the paint thickness increasing, the dielectric is getting close to the paint's properties. Waveguide is using here to measure the paint thickness effect for further UHF RFID study.

  2. Graphene Coating on Copper by Electrophoretic Deposition for Corrosion Prevention

    Directory of Open Access Journals (Sweden)

    N. Usha Kiran

    2017-11-01

    Full Text Available In this paper, we report the use of a simple and inexpensive electrophoretic deposition (EPD technique to develop thin, uniform, and transparent graphene oxide (GO coating on copper (Cu substrate on application of 10 V for 1 s from an aqueous suspension containing 0.03 wt % graphene oxide. GO was partially reduced during the EPD process itself. The GO coated on Cu was completely reduced chemically by using sodium borohydride (NaBH4 solution. The coatings were characterized by field emission scanning electron microscope (FESEM, Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR, XRD, and UV/VIS spectrophotometry. Corrosion resistance of the coatings was evaluated by electrochemical measurements under accelerated corrosion condition in 3.5 wt % NaCl solution. The GO coated on Cu and chemically reduced by NaBH4 showed more positive corrosion potential (Ecorr (−145.4 mV compared to GO coated on Cu (−182.2 mV and bare Cu (−235.3 mV, and much lower corrosion current (Icorr (7.01 µA/cm2 when compared to 15.375 µA/cm2 for bare Cu indicating that reduced GO film on copper exhibit enhanced corrosion resistance. The corrosion inhibition efficiency of chemically reduced GO coated Cu was 54.40%, and its corrosion rate was 0.08 mm/year as compared to 0.18 mm/year for bare copper.

  3. Characterisation of corrosion products on pipeline steel under cathodic protection

    Energy Technology Data Exchange (ETDEWEB)

    Lanarde, Lise [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33, 93211 Saint Denis La Plaine (France)]|[UPR15 du CNRS, Laboratoire des Interfaces et Systemes Electrochimiques, Universite Pierre et Marie Curie, C.P. 133, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Campaignolle, Xavier; Karcher, Sebastien; Meyer, Michel [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33, 93211 Saint Denis La Plaine (France); Joiret, Suzanne [UPR15 du CNRS, Laboratoire des Interfaces et Systemes Electrochimiques, Universite Pierre et Marie Curie, C.P. 133, 4 Place Jussieu 75252 Paris Cedex 05 (France)

    2004-07-01

    Onshore gas transmission lines are conjointly protected against external corrosion by cathodic protection (CP) and organic coatings. If both protection systems are simultaneously faulty, the pipe may be subjected to local loss of protection criteria. Consequently, the development of a corrosion due to the ground intrinsic corrosiveness may occur. To guarantee an optimal and safe use of its 31000 km buried gas transmission network, Gaz de France regularly inspects its pipelines. When indications of metal damage are suspected, excavations are realized to carry out a finer diagnosis and, if necessary, to repair. Whenever, corrosions are encountered, although it occurs very scarcely, it is necessary to evaluate its degree of gravity: activity, mechanism, and kinetics. Among corrosion defects, it is indeed essential to differentiate those active, from those older inactive at the time of excavation, since those last ones may possibly have been annihilated, by a PC reinforcement for instance. Eventually, the identification of the corrosion mechanism and its associated rate will provide an assessment of the risks encountered by other sections of the pipeline similar to that excavated. This study investigates to what extent the degree of gravity (activity, kinetics) of a corrosion can be determined by the characterization and identification of its associated corrosion products. Moreover, it will attempt to relate it to the close environment features as well as to the operating conditions of the pipe. The preliminary results presented in this paper consist in a laboratory study of the time evolution of corrosion products formed on the surface of ordinary low carbon steel samples. The specimens have been previously subjected to various polarization conditions in various aqueous media. The selected solutions are characteristic of ground waters. The main parameters considered for the definition of the media were its initial chemical composition, pH and dissolved gas composition

  4. Microstructure, corrosion and tribological and antibacterial properties of Ti-Cu coated stainless steel.

    Science.gov (United States)

    Jin, Xiaomin; Gao, Lizhen; Liu, Erqiang; Yu, Feifei; Shu, Xuefeng; Wang, Hefeng

    2015-10-01

    A Ti-Cu coated layer on 316L stainless steel (SS) was obtained by using the Closed Field Unbalanced Magnetron Sputtering (CFUBMS) system to improve antibacterial activity, corrosion and tribological properties. The microstructure and phase constituents of Ti-Cu coated layer were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge optical emission spectrometry (GDOES). The corrosion and tribological properties of a stainless steel substrate, SS316L, when coated with Ti-Cu were investigated in a simulated body fluid (SBF) environment. The viability of bacteria attached to the antibacterial surface was tested using the spread plate method. The results indicate that the Ti-Cu coated SS316L could achieve a higher corrosion polarization resistance and a more stable corrosion potential in an SBF environment than the uncoated SS316L substrate. The desirable corrosion protection performance of Ti-Cu may be attributable to the formation of a Ti-O passive layer on the coating surface, protecting the coating from further corrosion. The Ti-Cu coated SS316L also exhibited excellent wear resistance and chemical stability during the sliding tests against Si3N4 balls in SBF environment. Moreover, the Ti-Cu coatings exhibited excellent antibacterial abilities, where an effective reduction of 99.9% of Escherichia coli (E.coli) within 12h was achieved by contact with the modified surface, which was attributed to the release of copper ions when the Ti-Cu coatings are in contact with bacterial solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Corrosion Resistance of Copper Coatings Deposited by Cold Spraying

    Science.gov (United States)

    Winnicki, M.; Baszczuk, A.; Jasiorski, M.; Małachowska, A.

    2017-12-01

    In the article, a study of corrosion resistance of copper and copper-based cermet (Cu+Al2O3 and Cu+SiC) coatings deposited onto aluminum alloy substrate using the low-pressure cold spraying method is presented. The samples were subjected to two different corrosion tests at room temperature: (1) Kesternich test and (2) a cyclic salt spray test. The selected tests were allowed to simulate service conditions typical for urban, industrial and marine environment. Examination of corroded samples included analysis changes on the coating surface and in the microstructure. The physicochemical tests were carried out using x-ray diffraction to define corrosion products. Moreover, microhardness and electrical conductivity measurements were conducted to estimate mechanical and physical properties of the coatings after corrosion tests. XRD analysis clearly showed that regardless of corrosion conditions, for all samples cuprite (Cu2O) was the main product. However, in the case of Cu+Al2O3 cermet coating, chlorine- and sulfate-containing phases such as Cu2Cl(OH)3 (paracetamite) and Cu3(SO4)(OH)4 (antlerite) were also recorded. This observation gives better understanding of the lowest microstructure changes observed for Cu+Al2O3 coating after the corrosion tests. This is also a justification for the lowest decrease in electrical conductivity registered after the corrosion tests for this coating.

  6. Corrosion Resistance of Copper Coatings Deposited by Cold Spraying

    Science.gov (United States)

    Winnicki, M.; Baszczuk, A.; Jasiorski, M.; Małachowska, A.

    2017-10-01

    In the article, a study of corrosion resistance of copper and copper-based cermet (Cu+Al2O3 and Cu+SiC) coatings deposited onto aluminum alloy substrate using the low-pressure cold spraying method is presented. The samples were subjected to two different corrosion tests at room temperature: (1) Kesternich test and (2) a cyclic salt spray test. The selected tests were allowed to simulate service conditions typical for urban, industrial and marine environment. Examination of corroded samples included analysis changes on the coating surface and in the microstructure. The physicochemical tests were carried out using x-ray diffraction to define corrosion products. Moreover, microhardness and electrical conductivity measurements were conducted to estimate mechanical and physical properties of the coatings after corrosion tests. XRD analysis clearly showed that regardless of corrosion conditions, for all samples cuprite (Cu2O) was the main product. However, in the case of Cu+Al2O3 cermet coating, chlorine- and sulfate-containing phases such as Cu2Cl(OH)3 (paracetamite) and Cu3(SO4)(OH)4 (antlerite) were also recorded. This observation gives better understanding of the lowest microstructure changes observed for Cu+Al2O3 coating after the corrosion tests. This is also a justification for the lowest decrease in electrical conductivity registered after the corrosion tests for this coating.

  7. Effect of heat treatment on corrosion behavior of duplex coatings

    Directory of Open Access Journals (Sweden)

    K. Raghu Ram Mohan Reddy

    2017-01-01

    Full Text Available In the present paper, duplex WC-Co/NiCrAlY coating is coated onto Ti6Al4V substrate and vacuum heat treatment is employed to investigate the corrosion behavior of heat treated samples as well as Ti6Al4V substrate for comparison. In this duplex coating system, High Velocity Oxy Fuel (HVOF process is used to deposit NiCrAlY interlayer with a constant thickness of 200 μm and WC-Co ceramic top layer with varying thickness of 250 μm, 350 μm and 450 μm deposited by Detonation Spray (DS process. Different heat treatment temperatures (600–1150 °C were employed for the coated samples to study the microstructure and the effect on corrosion resistance of the duplex coatings. Potentiodynamic polarization tests were carried to investigate the corrosion performance of duplex coated heat treated samples and the substrate in Ringer’s solution at 37 °C and prepared the pH to 5.7. The microstructure upon corrosion after heat treatment was characterized by SEM analysis to understand the corrosion behavior. The results disclosed that at all heat treatment temperatures, all the coated samples exhibited better corrosion resistance than the base substrate. However, during 950 °C and 1150 °C heat treatment temperatures, it was observed highest corrosion potential than 600 °C and 800 °C. The 350 μm thickness, coated sample exhibited highest corrosion resistance compared to other two coated samples and the substrate at all heat treatment temperatures.

  8. CHARACTERISTICS OF PROTECTIVE COATINGS

    Directory of Open Access Journals (Sweden)

    Seljaev Vladimir Pavlovich

    2012-09-01

    Full Text Available On the basis of the computer program «Statistical analysis of color components for paint and varnish coatings», methods are suggested and experimental results are obtained for decorative characteristics polyurethane coatings.

  9. Recent Developments on Autonomous Corrosion Protection Through Encapsulation

    Science.gov (United States)

    Li, W.; Buhrow, J. W.; Calle, L. M.; Gillis, M.; Blanton, M.; Hanna, J.; Rawlins, J.

    2015-01-01

    This paper concerns recent progress in the development of a multifunctional smart coating, based on microencapsulation, for the autonomous detection and control of corrosion. Microencapsulation has been validated and optimized to incorporate desired corrosion control functionalities, such as early corrosion detection and inhibition, through corrosion-initiated release of corrosion indicators and inhibitors, as well as self-healing agent release triggered by mechanical damage. While proof-of-concept results have been previously reported, more recent research and development efforts have concentrated on improving coating compatibility and synthesis procedure scalability, with a targeted goal of obtaining easily dispersible pigment-grade type microencapsulated materials. The recent progress has resulted in the development of pH-sensitive microparticles as a corrosion-triggered delivery system for corrosion indicators and inhibitors. The synthesis and early corrosion indication results obtained with coating formulations that incorporate these microparticles are reported. The early corrosion indicating results were obtained with color changing and with fluorescent indicators.

  10. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

  11. Bioactive glass-ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ye Xinyu [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Cai Shu, E-mail: caishu@tju.edu.cn [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Dou Ying [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China); Xu Guohua [Shanghai Changzheng Hospital, Shanghai 200003 (China); Huang Kai; Ren Mengguo; Wang Xuexin [Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Sol-gel derived 45S5 glass-ceramic coating was prepared on Mg alloy substrate. Black-Right-Pointing-Pointer The corrosion resistance of glass-ceramic coated Mg alloy was markedly improved. Black-Right-Pointing-Pointer The corrosion behavior of the coated sample varied due to the cracking of coating. - Abstract: In this work, a bioactive 45S5 glass-ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol-gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass-ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na{sub 2}Ca{sub 2}Si{sub 3}O{sub 9}, with the thickness of {approx}1.0 {mu}m, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential (E{sub corr}) form -1.60 V to -1.48 V, and a reduction of corrosion current density (i{sub corr}) from 4.48 {mu}A cm{sup -2} to 0.16 {mu}A cm{sup -2}, due to the protection provided by the glass-ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass-ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass-ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

  12. Advancement in corrosion resistance of AA 2024-T3 through sol-gel coatings including nanocontainers

    Directory of Open Access Journals (Sweden)

    Kartsonakis Ioannis A.

    2017-01-01

    Full Text Available The current study investigates the effect of nanocontainers incorporation into sol-gel coatings for the protection improvement of aluminium alloys 2024-T3 against corrosion. The nanocontainers were synthesized via a combination of radical polymerization process and sol-gel technique. They consist of cerium and molybdenum oxides and loaded with the anodic corrosion inhibitor 2-mercaptobenzothiazole (MBT. The preparation of the coating matrix was accomplished using (3-glycidoxypropyltrimethoxysilane as precursor. These organic modified silicate based sol-gel films were evaluated for their corrosion behaviour as well as nanomechanical properties using electrochemical and nanoindentation techniques, respectively. The results reveal that the presence of loaded nanocontainers improved the corrosion protection of the coatings; outcome that can be attributed to either the increase coherence of the coating or the simultaneously inhibition action of cerium and molybdate ions together with the corrosion inhibitor MBT. Moreover, the addition of nanocontainers empty or loaded with inhibitor amount strengthens (increase of wear resistance the coating and decreases the coefficient of friction.

  13. Corrosion Testing of Thermal Spray Coatings in a Biomass Co-Firing Power Plant

    Directory of Open Access Journals (Sweden)

    Maria Oksa

    2016-11-01

    Full Text Available Large-scale use of biomass and recycled fuel is increasing in energy production due to climate and energy targets. A 40% cut in greenhouse gas emission compared to 1990 levels and at least a 27% share of renewable energy consumption are set in EU Energy Strategy 2030. Burning fuels with high content of corrosive species such as chlorine and heavy metals causes deterioration of boiler components, shortened lifetime, limited availability of a plant and hence higher maintenance and investment costs and lower thermal and economic efficiency. Coatings can be applied to protect the critical boiler components against high temperature corrosion. In this study, five thermal spray coatings were tested in an actual biomass co-firing boiler for 1300 h with a measurement probe. The coatings were analyzed after the exposure by metallographic means and scanning electron microscope/energy-dispersive X-ray spectroscope (SEM/EDX. The deposits formed on the specimens were analyzed by X-ray fluorescence. At 550 °C, the coatings showed excellent corrosion performance compared to reference material ferritic steel T92. At 750 °C, tube material A263 together with NiCr and NiCrTi had the highest corrosion resistance. To conclude, thermal spray coatings can offer substantial corrosion protection in biomass and recycled fuel burning power plants.

  14. Corrosion Protection and Surface Treatment of Magnesium Alloys Used for Orthopedic Applications

    Directory of Open Access Journals (Sweden)

    Nabil Nassif

    2013-01-01

    Full Text Available An overview is reported about the history of prevailing magnesium alloys as orthopedic biodegradable materials. Important features of the effect of alloying additions, along with surface treatments for corrosion protection of magnesium alloys, are described. Hydroxyapatite (HA, the promising coat deposited by different direct and electrochemical methods to tailor corrosion resistance and biocompatibility, is discussed. Surface modifications, such as microarc oxidation or anodization which lead to nanostructures fabricated to provide better adhesion for HA coatings, are presented.

  15. Wear and corrosion behaviour of Al2O3-TiO2 coatings produced by flame thermal projection

    Science.gov (United States)

    Forero-Duran, M.; Dulce-Moreno, H. J.; Ferrer-Pacheco, M.; Vargas-Galvis, F.

    2017-12-01

    Evaluated the wear resistance and the coatings corrosion behaviour of Al2O3-TiO2 prepared by thermal spraying by flame on AISI 1020 carbon steel substrates, previously coated with an alloy base Ni. For this purpose, were controlled parameters of thermal spraying and the use of powders of similar but different chemical composition is taken as a variable commercial reference for ceramic coating. SEM images allowed to know the morphology of the powders and coatings. Electrochemical techniques (Tafel) were applied to evaluate the protection against corrosion. Coatings were tested for wear with a tribometer configuration bola-disco. It was determined that the phases present in coatings are directly relate to the behaviour against corrosion and wear them. Keywords: wear, corrosion, thermal imaging.

  16. Structurally Integrated Coatings for Wear and Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Beardsley, M. Brad; Sebright, Jason L.

    2008-11-18

    Wear and corrosion of structures cuts across industries and continues to challenge materials scientists and engineers to develop cost effective solutions. Industries typically seek mature technologies that can be implemented for production with rapid or minimal development and have little appetite for the longer-term materials research and development required to solve complex problems. The collaborative work performed in this project addressed the complexity of this problem in a multi-year program that industries would be reluctant to undertake without government partnership. This effort built upon the prior development of Advanced Abrasion Resistant Materials conduct by Caterpillar Inc. under DOE Cooperative Agreement No. DE-FC26-01NT41054. In this referenced work, coatings were developed that exhibited significant wear life improvements over standard carburized heat treated steel in abrasive wear applications. The technology used in this referenced work, arc lamp fusing of thermal spray coatings, was one of the primary technical paths in this work effort. In addition to extending the capability of the coating technology to address corrosion issues, additional competitive coating technologies were evaluated to insure that the best technology was developed to meet the goals of the program. From this, plasma transferred arc (PTA) welding was selected as the second primary technology that was investigated. Specifically, this project developed improved, cost effective surfacing materials and processes for wear and corrosion resistance in both sliding and abrasive wear applications. Materials with wear and corrosion performance improvements that are 4 to 5 times greater than heat treated steels were developed. The materials developed were based on low cost material systems utilizing ferrous substrates and stainless steel type matrix with hard particulates formed from borides and carbides. Affordability was assessed against other competing hard surfacing or coating

  17. Mitigating Localized Corrosion Using Thermally Sprayed Aluminum (TSA) Coatings on Welded 25% Cr Superduplex Stainless Steel

    Science.gov (United States)

    Paul, S.; Lu, Q.; Harvey, M. D. F.

    2015-04-01

    Thermally sprayed aluminum (TSA) coating has been increasingly used for the protection of carbon steel offshore structures, topside equipment, and flowlines/pipelines exposed to both marine atmospheres and seawater immersion conditions. In this paper, the effectiveness of TSA coatings in preventing localized corrosion, such as pitting and crevice corrosion of 25% Cr superduplex stainless steel (SDSS) in subsea applications, has been investigated. Welded 25% Cr SDSS (coated and uncoated) with and without defects, and surfaces coated with epoxy paint were also examined. Pitting and crevice corrosion tests, on welded 25% Cr SDSS specimens with and without TSA/epoxy coatings, were conducted in recirculated, aerated, and synthetic seawater at 90 °C for 90 days. The tests were carried out at both the free corrosion potentials and an applied cathodic potential of -1100 mV saturated calomel electrode. The acidity (pH) of the test solution was monitored daily and adjusted to between pH 7.5 and 8.1, using dilute HCl solution or dilute NaOH, depending on the pH of the solution measured during the test. The test results demonstrated that TSA prevented pitting and crevice corrosion of 25% Cr SDSS in artificial seawater at 90 °C, even when 10-mm-diameter coating defect exposing the underlying steel was present.

  18. The Corrosion Protection of Magnesium Alloy AZ31B

    Science.gov (United States)

    Danford, M. D.; Mendrek, M. J.; Mitchell, M. L.; Torres, P. D.

    1997-01-01

    Corrosion rates for bare and coated Magnesium alloy AZ31B have been measured. Two coatings, Dow-23(Trademark) and Tagnite(Trademark), have been tested by electrochemical methods and their effectiveness determined. Electrochemical methods employed were the scanning reference electrode technique (SRET), the polarization resistance technique (PR) and the electrochemical impedance spectroscopy technique (EIS). In addition, general corrosion and stress corrosion methods were employed to examine the effectiveness of the above coatings in 90 percent humidity. Results from these studies are presented.

  19. Self-cleaning performance of superhydrophobic hybrid nanocomposite coatings on Al with excellent corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Raj, V., E-mail: alaguraj2@rediffmail.com; Mohan Raj, R., E-mail: chem_mohan@rediffmail.com

    2016-12-15

    Highlights: • Ceramic-poly(Ani-co-oPD) coatings were formed on Al by anodization and electro-polymerisation techniques. • The superhydrophobic coating was fabricated on copolymer by electrodeposition of zinc stearate. • The superhydrophobicity mechanism relies on morphologies and chemical components on surface is the key factor. • Ceramic-poly(Ani-co-oPD)-zinc stearate coated Al has excellent corrosion resistance and good self-cleaning performance. - Abstract: Protective ceramic-PANI, ceramic-poly(Ani-co-oPD) and ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coatings were formed on Al surface by the processes involving anodization, electropolymerisation and electrodeposition under optimum conditions. The prepared nanocomposite coatings were evaluated by ATR-IR and XRD studies. SEM studies performed on nanocomposite coatings reveal that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating shows a cauliflower-like cluster with crack-free morphology compared to ceramic-PANI and ceramic-poly(Ani-co-oPD) nanocomposite coatings. The mechanical properties of different nanocomposite coatings were measured using Vicker microhardness tester and Taber Abrasion tester. The ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite has higher mechanical stability. The corrosion resistance of the coatings measured by Tafel polarization and electrochemical impedance spectroscopy, shows that ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coated aluminum has higher corrosion resistance than other coatings and bare Al. Wettability studies prove that superhydrophobic nature of ceramic-poly(Ani-co-oPD)-zinc stearate nanocomposite coating with contact angle of 155.8° is responsible for good self-cleaning property and excellent corrosion resistance of aluminum.

  20. Corrosion Resistance Properties of Aluminum Coating Applied by Arc Thermal Metal Spray in SAE J2334 Solution with Exposure Periods

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2016-03-01

    Full Text Available Arc thermal metal spray coating provides excellent corrosion, erosion and wear resistance to steel substrates. This paper incorporates some results of aluminum coating applied by this method on plain carbon steel. Thereafter, coated panels were exposed to an environment known to form stable corrosion products with aluminum. The coated panels were immersed in Society of Automotive Engineers (SAE J2334 for different periods of time. This solution consists of an aqueous solution of NaCl, CaCl2 and NaHCO3. Various electrochemical techniques, i.e., corrosion potential-time, electrochemical impedance spectroscopy (EIS and the potentiodynamic were used to determine the performance of stimulants in improving the properties of the coating. EIS studies revealed the kinetics and mechanism of corrosion and potentiodynamic attributed the formation of a passive film, which stifles the penetration of aggressive ions towards the substrate. The corrosion products that formed on the coating surface, identified using Raman spectroscopy, were Dawsonite (NaAlCO3(OH2 and Al(OH3. These compounds of aluminum are very sparingly soluble in aqueous solution and protect the substrate from pitting and uniform corrosion. The morphology and composition of corrosion products determined by scanning electron microscopy and energy dispersive X-ray analyses indicated that the environment plays a decisive role in improving the corrosion resistance of aluminum coating.

  1. Nanostructured Protective Coatings

    Science.gov (United States)

    2006-01-01

    understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades, and developing a versatile...Phase I objectives, particularly in enhancing the understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V ...understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades, and developing a versatile

  2. Development of Nb{sub 2}O{sub 5}|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures; Desenvolvimento e uso do composito de Nb{sub 2}O{sub 5}|Cu como revestimento aplicado por aspersao termica sobre o aco AISI 1020 para protecao contra a corrosao pelo solo em estruturas enterradas

    Energy Technology Data Exchange (ETDEWEB)

    Regis Junior, Oscar [Universidade Tecnologica Federal do Parana, Ponta Grossa, PR (Brazil). Dept. de Mecanica; Silva, Jose Maurilio da; Portella, Kleber Franke [Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Dept. de Pesquisa em Engenharia Civil; Paredes, Ramon Sigifredo Cortes, E-mail: regis@utfpr.edu.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Mecanica

    2012-07-01

    An Nb{sub 2}O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb{sub 2}O{sub 5}|Cu composite for use in buried structure protection. (author)

  3. Effects of temperature on the corrosion behavior of coated carbon steel in 1 wt.% sodium chloride (NaCl) solution

    Science.gov (United States)

    Razak, Khalil Abdul; Fuad, Mohd Fazril Irfan Ahmad; Alias, Nur Hashimah; Othman, Nur Hidayati; Zahari, Muhammad Imran

    2017-12-01

    Special attention has been paid in the past decade on the use of metal corrosion protection to conserve natural resources and to improve the performance of engine, build structures and other equipment. Coating is considered as one of the promising methods that can be used to protect the metal against corrosion. However, not many attentions have been given on the evaluation of coating mechanism towards corrosion protection. In this work, the performance of zinc-rich paint (ZRP) was investigated under saltwater environment as to simulate the nature of corrosion in seawater. The adhesion of the coated steel was also studied to determine the adherence of the coatings to the metal substrate. Results obtained from the immersion test was then used to determine the corrosion rate of the coatings. The mechanisms and the function of ZRP as a protection layer were also investigated. By using 3 coated system of ZRP, the corrosion rate of the steel was observed to decrease thus provide better protection in seawater environment.

  4. 49 CFR 192.463 - External corrosion control: Cathodic protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Cathodic protection... for Corrosion Control § 192.463 External corrosion control: Cathodic protection. (a) Each cathodic protection system required by this subpart must provide a level of cathodic protection that complies with one...

  5. Corrosion Degradation of Coated Aluminum Alloy Systems through Galvanic Interactions

    Science.gov (United States)

    2017-07-19

    Corrosion  Degradation  of  Coated  Aluminum  Alloy  Systems  through  Galvanic...their  low  density  and  relatively  high  strength.   While  exhibiting  significant  general   corrosion  resistance,  these...alloys  are  susceptible  to  various  forms  of   localized   corrosion ,  such  as  pitting,  intergranular   corrosion

  6. Corrosion performance of zinc coated steel in seawater environment

    Science.gov (United States)

    Liu, Shuan; Zhao, Xia; Zhao, Haichao; Sun, Huyuan; Chen, Jianmin

    2017-03-01

    Considering the continuous exploitation of marine resources, it is very important to study the anticorrosion performance and durability of zinc coated streel (ZCS) because its increasing use as reinforcements in seawater. Tafel polarization curves and linear polarization curves combined with electrochemical impedance spectroscopy (EIS) were employed to evaluate the corrosion performance of ZCS at Qingdao test station during long-term immersion in seawater. The results indicated that the corrosion rate of the ZCS increased obviously with immersion time in seawater. The corrosion products that formed on the zinc coated steel were loose and porous, and were mainly composed of Zn5(OH)8Cl2, Zn5(OH)6(CO3)2, and ZnO. Pitting corrosion occurred on the steel surface in neutral seawater, and the rate of ZCS corrosion decreased with increasing pH.

  7. Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

    Science.gov (United States)

    He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua

    2015-03-01

    Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings.

  8. Hydroxyapatite/poly(epsilon-caprolactone) double coating on magnesium for enhanced corrosion resistance and coating flexibility.

    Science.gov (United States)

    Jo, Ji-Hoon; Li, Yuanlong; Kim, Sae-Mi; Kim, Hyoun-Ee; Koh, Young-Hag

    2013-11-01

    Hydroxyapatite was deposited on pure magnesium (Mg) with a flexible poly(ε-caprolactone) interlayer to reduce the corrosion rate of Mg and enhance coating flexibility. The poly(ε-caprolactone) interlayer was uniformly coated on Mg by a spraying method, followed by hydroxyapatite deposition on the poly(ε-caprolactone) using an aerosol deposition method. In scanning electron microscopy observations, inorganic/organic composite-like structure was observed between the hydroxyapatite and poly(ε-caprolactone) layers, resulting from the collisions of hydroxyapatite particles into the poly(ε-caprolactone) matrix at the initial stage of the aerosol deposition. The corrosion resistance of the coated Mg was examined using potentiodynamic polarization tests. The hydroxyapatite/poly(ε-caprolactone) double coating remarkably improved the corrosion resistance of Mg in Hank's solution. In the in vitro cell tests, the coated Mg showed better cell adhesion compared with the bare Mg due to the reduced corrosion rate and enhanced biocompatibility. The stability and flexibility of hydroxyapatite/poly(ε-caprolactone) double coating was investigated by scanning electron microscopy inspections after the coated Mg was deformed. The hydroxyapatite coating on the poly(ε-caprolactone) interlayer revealed enhanced coating stability and flexibility without cracking or delamination during bending and stretching compared with the hydroxyapatite single coating. These results demonstrated that the hydroxyapatite/poly(ε-caprolactone) double coating significantly improved the surface corrosion resistance of Mg and enhanced coating flexibility for use of Mg as a biodegradable implant.

  9. Corrosion study of the graphene oxide and reduced graphene oxide-based epoxy coatings

    Science.gov (United States)

    Ghauri, Faizan Ali; Raza, Mohsin Ali; Saad Baig, Muhammad; Ibrahim, Shoaib

    2017-12-01

    This work aims to determine the effect of graphene oxide (GO) and reduced graphene oxide (rGO) incorporation as filler on the corrosion protection ability of epoxy coatings in saline media. GO was derived from graphite powder following modified Hummers’ method, whereas rGO was obtained after reduction of GO with hydrazine solution. About 1 wt.% of GO or rGO were incorporated in epoxy resin by solution mixing process followed by ball milling. GO and rGO-based epoxy composite coatings were coated on mild steel substrates using film coater. The coated samples were characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests after 1 and 24 h immersion in 3.5% NaCl. The results suggested that GO-based epoxy composite coatings showed high impedance and low corrosion rate.

  10. A new architecture for a factual materials database on coatings and high temperature corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Streiff, R.; Vaugelade, S. [Univ. de Provence, Marseille (France); Komornicki, S. [Akademia Gorniczo-Hutnicza, Cracow (Poland); Boone, D.H. [Boone and Associates, Walnut Creek, CA (United States)

    1997-12-31

    C and HTC-DATA a data bank on coatings and high temperature corrosion, has been created to help in choosing coatings for specific applications, knowing their fabrication process characteristics and their protectivity characteristics. This relational data bank will include five databases, viz. (1) a bibliographic reference data base, (2) a directory of addresses of companies and researchers involved in the field, (3) a numerical database on alloy composition, (4) a factual coatings database, and (5) a factual corrosion database. Building of these factual databases first followed the classical MERISE analytical treatment for data organisation. However, the variety of coating characteristics has resulted in a very complex database structure with a very large number of tables and fields. Therefore, a new approach for the architecture of the coating database based upon a thesaurus to describe the data has been perfected which is presented in this paper. (orig.) 13 refs.

  11. Studies on broad spectrum corrosion resistant oxide coatings

    Indian Academy of Sciences (India)

    The corrosion resistant oxide coatings, developed and applied by the conventional vitreous enamelling techniques, showed superior resistance to a range of mineral acids at various strengths and temperatures, alkaline solutions, boiling water and chrome plating solutions. These coatings possess considerable abrasion ...

  12. Electrolytic deposition and corrosion resistance of Zn–Ni coatings ...

    Indian Academy of Sciences (India)

    Zn–Ni coatings were deposited under galvanostatic conditions on steel substrate (OH18N9). The influence of current density of deposition on the surface morphology, chemical and phase composition was investigated. The corrosion resistance of Zn–Ni coatings obtained at current density 10–25 mA cm-2 are measured, ...

  13. Electrodeposition and corrosion properties of zn-co and zn-co-fe alloy coatings

    NARCIS (Netherlands)

    Mol, J.M.C.; Lodhi, Z.F.; Hovestad, A.; Hoen-Velterop, L. 't; Terryn, H.; Wit, J.H.W. de

    2010-01-01

    Cadmium (Cd) has been extensively used as an excellent corrosion protective coating for steel components in aerospace, automotive, electrical and fasteners industries. However, Cd is banned due to its toxic nature and strict environmental regulations. In this study, the electrodeposition mechanism

  14. Preparation of Phytic Acid/Silane Hybrid Coating on Magnesium Alloy and Its Corrosion Resistance in Simulated Body Fluid

    Science.gov (United States)

    Wang, Fengwu; Cai, Shu; Shen, Sibo; Yu, Nian; Zhang, Feiyang; Ling, Rui; Li, Yue; Xu, Guohua

    2017-09-01

    In order to decrease the corrosion rate and improve the bioactivity of magnesium alloy, phytic acid/saline hybrid coatings were synthesized on AZ31 magnesium alloys by sol-gel dip-coating method. It was found that the mole ratio of phytic acid to γ-APS had a great influence on coating morphology and the corresponding corrosion resistance of the coated magnesium alloys. When the mole ratio of phytic acid to γ-APS was 1:1, the obtained hybrid coating was integral and without cracks, which was ascribed to the strong chelate capability of phytic acid and Si-O-Si network derived from silane. Electrochemical test result indicated that the corrosion resistance of the coated magnesium alloy was about 27 times larger than that of the naked counterpart. In parallel, immersion test showed that the phytic acid/silane hybrid coating could induce CaP-mineralized product deposition, which offered another protection for magnesium alloy.

  15. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  16. Effect of molybdate on phosphating of Nd-Fe-B magnets for corrosion protection

    Directory of Open Access Journals (Sweden)

    Adonis Marcelo Saliba-Silva

    2005-06-01

    Full Text Available Nd-Fe-B magnets are highly susceptible to corrosion and need protection against environment attack. The use of organic coatings is one of the main methods of corrosion protection of these materials. Data related to the effect of conversion coatings, such as phosphating, on corrosion performance of these magnets is still scarce. Studies about the effect of phosphating on the corrosion resistance of a commercial Nd-Fe-B sintered magnet indicated that it increases the corrosion resistance of these magnets, compared to non-phosphated magnets. In this study, the solution chemistry of a phosphating bath was altered with the addition of molybdate and its effect on the corrosion resistance of magnets investigated. Sintered magnet specimens were phosphated in solutions of 10 g/L NaH2PO4 (pH 3.8, either with or without molybdate [10-3 M MoO4(2-], to improve their corrosion resistance. The effect of phosphating time was also evaluated, and specimens were phosphated for 4 and 18 hours. To evaluate the corrosion performance of phosphated and unphosphated specimens, a corrosion test based on monitoring hydrogen evolution on the surface of the magnets was used. This technique revealed that the addition of molybdate to the phosphating solution improved the corrosion resistance of the magnets phosphated by immersion for short periods but had no beneficial effect if phosphated by immersion for longer periods.

  17. Novel Thiol-Ene Hybrid Coating for Metal Protection

    Directory of Open Access Journals (Sweden)

    Mona Taghavikish

    2016-04-01

    Full Text Available A novel hybrid anticorrosion coating with dual network of inorganic (Si–O–Si and organic bonds (C–S–C was prepared on metal through an in situ sol-gel and thiol-ene click reaction. This novel interfacial thin film coating incorporates (3-mercaptopropyl trimethoxysilane (MPTS and 1,4-di(vinylimidazolium butane bisbromide based polymerizable ionic liquid (PIL to form a thiol-ene based photo-polymerized film, which on subsequent sol-gel reaction forms a thin hybrid interfacial layer on metal surface. On top of this PIL hybrid film, a self-assembled nanophase particle (SNAP coating was employed to prepare a multilayer thin film coating for better corrosion protection and barrier performance. The novel PIL hybrid film was characterised for structure and properties using Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA. The corrosion protection performance of the multilayer coating was examined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. The results reveal that this novel double layer coating on metal offers excellent protection against corrosion and has remarkably improved the barrier effect of the coating.

  18. Erosion–corrosion and corrosion properties of DLC coated low temperature Erosion–corrosion and corrosion properties of DLC coated low temperature

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Christiansen, Thomas; Hilbert, Lisbeth Rischel

    2009-01-01

    of AISI 316 as substrate for DLC coatings are investigated. Corrosion and erosion–corrosion measurements were carried out on low temperature nitrided stainless steel AISI 316 and on low temperature nitrided stainless steel AISI 316 with a top layer of DLC. The combination of DLC and low temperature...... nitriding dramatically reduces the amount of erosion–corrosion of stainless steel under impingement of particles in a corrosive medium.......Lowtemperature nitriding of stainless steel leads to the formation of a surface zone of so-called expanded austenite, i.e. by dissolution of large amounts of nitrogen in solid solution. In the present work the possibility of using nitrogen expanded austenite “layers” obtained by gaseous nitriding...

  19. Corrosion resistant coatings suitable for elevated temperature application

    Science.gov (United States)

    Chan, Kwai S [San Antonio, TX; Cheruvu, Narayana Sastry [San Antonio, TX; Liang, Wuwei [Austin, TX

    2012-07-31

    The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.

  20. Corrosion behavior of mesoporous bioglass-ceramic coated magnesium alloy under applied forces.

    Science.gov (United States)

    Zhang, Feiyang; Cai, Shu; Xu, Guohua; Shen, Sibo; Li, Yan; Zhang, Min; Wu, Xiaodong

    2016-03-01

    In order to research the corrosion behavior of bioglass-ceramic coated magnesium alloys under applied forces, mesoporous 45S5 bioactive glass-ceramic (45S5 MBGC) coatings were successfully prepared on AZ31 substrates using a sol-gel dip-coating technique followed by a heat treatment at the temperature of 400°C. In this work, corrosion behavior of the coated samples under applied forces was characterized by electrochemical tests and immersion tests in simulated body fluid. Results showed that the glass-ceramic coatings lost the protective effects to the magnesium substrate in a short time when the applied compressive stress was greater than 25MPa, and no crystallized apatite was formed on the surface due to the high Mg(2+) releasing and the peeling off of the coatings. Whereas, under low applied forces, apatite deposition and crystallization on the coating surface repaired cracks to some extent, thus improving the corrosion resistance of the coated magnesium during the long-term immersion period. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Recent Developments on Microencapsulation for Autonomous Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Fitzpatrick, Lilliana; Jolley, Scott T.; Surma, Jan M.; Pearman, Benjamin P.; Zhang, Xuejun

    2014-01-01

    This work concerns recent progress in the development of a multifunctional smart coating based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of desired corrosion control functionalities, such as early corrosion detection and inhibition through corrosion controlled release of corrosion indicators and inhibitors, as well as self-healing agent release when mechanical damage occurs.While proof-of-concept results have been reported previously, more recent efforts have been concentrated in technical developments to improve coating compatibility, synthesis procedure scalability, as well as fine tuning the release property of encapsulated active agents.

  2. Protective Woodcutting Tool Coatings

    Directory of Open Access Journals (Sweden)

    Svetlana D. Latushkina

    2016-01-01

    Full Text Available The modern woodworking industry applies resource-saving, environmentally appropriate technologies, providing both the metal removal performance enhancement and functioning with the optimal economic factors. Progressive cutting parameters require the application of the high-reliability cutting tools, eliminating machine-tool equipment standstill and increased cost of the expensive tool materials. In this paper it is suggested to increase the wood-cutting tool efficiency by means of the vacuum-arc separated coating deposition process optimization. The droplets are one of the main problems while generating vacuum-arc coatings, and they have a bad influence on the quality and operational coatings characteristics. The application of the separated system, allowing minimize the droplets content, is one of the most promising ways to solve this problem. Vacuum-arc deposition technique was used in this work to generate multicomponent coatings. The coatings deposition was directly carried out on the modernized vacuum-arc plant, equipped by Y-shaped macroparticles separator.

  3. Corrosion behavior of tantalum-coated cobalt-chromium modular necks compared to titanium modular necks in a simulator test.

    Science.gov (United States)

    Dorn, Ulrich; Neumann, Daniel; Frank, Mario

    2014-04-01

    This study compared the corrosion behavior of tantalum-coated cobalt-chromium modular necks with that of titanium alloy modular necks at their junction to titanium-alloy femoral stem. Tests were performed in a dry assembly and two wet assemblies, one contaminated with calf serum and the other contaminated with calf serum and bone particles. Whereas the titanium modular neck tested in the dry assembly showed no signs of corrosion, the titanium modular necks tested in both wet assemblies showed marked depositions and corrosive attacks. By contrast, the tantalum-coated cobalt-chromium modular necks showed no traces of corrosion or chemical attack in any of the three assemblies. This study confirms the protective effect of tantalum coating the taper region of cobalt-chromium modular neck components, suggesting that the use of tantalum may reduce the risk of implant failure due to corrosion. © 2014.

  4. Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel

    Directory of Open Access Journals (Sweden)

    Joseph B. AGBOOLA

    2009-07-01

    Full Text Available Steel has found wide application in hot rolling equipments in the steel industry and the oil rig structures in sea water. These equipments are frequently subjected to corrosive and temperature condition which causes severe damage to them, hence the need to develop steel suitable to withstand these conditions in terms of surface treatment. This research work investigates the effect of FeCrAlY coating on mild steel under high temperature and aggressive environment. Iron based coatings are used due to low cost among other properties such as good corrosion resistance, ease of machining and high ductility when compared to hard metals.Thermal spraying of the specimens was carried out using high velocity oxygen fuel (HVOF. Corrosion test was carried out on both coated and uncoated samples. All samples were subjected to the same high temperature treatment for oxidation test.

  5. Improved corrosion protection of aluminum alloys by low-temperature plasma interface engineering

    Science.gov (United States)

    Reddy, Chandra Mudupu

    The System Approach Interface Engineering (SAIE) concept was employed to develop corrosion protection processes for aluminum (Al) alloys by application of a low temperature plasma interface engineering technique with a cathodic electrocoat (E-coat) as the primary layer coating. The SAIE concept emphasizes that the corrosion protection property of the coated system for Al alloys depends on the total system rather than any good corrosion protection component of the system. The cathodic E-coated SAIE plasma pretreatments on Alclad 2024-T3, 2024-T3 bare and 7075-T6 bare alloys showed excellent corrosion resistance property when tested by SO2 and Prohesion salt spray tests. These systems out performed the conventional conversion coated controls, chromate conversion coated then Deft primer coated (CC Deft) and chromate conversion coated then cathodic E-coated (CC E-coat) in both the corrosion testes. The corrosion protection by SAIE systems depends on three major factors; (1) improved barrier characteristics of E-coat, (2) water insensitive adhesion of E-coat to plasma polymers deposited in a DC discharge and (3) creating a stable surface oxide layer by plasma treatment or chemical cleaning. Different chemical pretreatments were employed to create a stable barrier type aluminum oxide layer on the surfaces of the substrates prior to plasma polymer deposition. The surface analysis showed that these pretreatments depend on the type of alloy and surface chemistry. As received surfaces with acetone wipe and plasma cleaning of the organic contaminants was found to be best for Alclad 2024-T3 alloy. Chemical alkaline cleaning for 2024-T3 bare and alkaline cleaning followed by deoxidization for 7075-T6 bare alloy were necessary. The adhesion of the cathodic E-coat was improved by surface energy matching techniques by deposition of various plasma polymer films of trimethylsilane (TMS) and mixtures of TMS with O2, H2, and N2. The adhesion performance evaluated by the N

  6. 49 CFR 195.559 - What coating material may I use for external corrosion control?

    Science.gov (United States)

    2010-10-01

    ... corrosion control? 195.559 Section 195.559 Transportation Other Regulations Relating to Transportation...) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Corrosion Control § 195.559 What coating material may I use for external corrosion control? Coating material for external corrosion control under...

  7. The effect of superhydrophobic wetting state on corrosion protection--the AKD example.

    Science.gov (United States)

    Ejenstam, Lina; Ovaskainen, Louise; Rodriguez-Meizoso, Irene; Wågberg, Lars; Pan, Jinshan; Swerin, Agne; Claesson, Per M

    2013-12-15

    Corrosion is of considerable concern whenever metal is used as construction material. In this study we address whether superhydrophobic coatings could be used as part of an environmentally friendly corrosion-protective system, and specific focus is put on how the wetting regime of a superhydrophobic coating affects corrosion inhibition. Superhydrophobic alkyl ketene dimer (AKD) wax coatings were produced, using different methods resulting in hierarchical structures, where the coatings exhibit the same surface chemistry but different wetting regimes. Contact angle measurements, ESEM, confocal Raman microscopy, open circuit potential and electrochemical impedance spectroscopy were used to evaluate the surfaces. Remarkably high impedance values of 10(10)Ω cm(2) (at 10(-2) Hz) were reached for the sample showing superhydrophobic lotus-like wetting. Simultaneous open circuit potential measurements suggest that the circuit is broken, most likely due to the formation of a thin air layer at the coating-water interface that inhibits ion transport from the electrolyte to the metal substrate. The remaining samples, showing superhydrophobic wetting in the rose state and hydrophobic Wenzel-like wetting, showed less promising corrosion-protective properties. Due to the absence of air films on these surfaces the coatings were penetrated by the electrolyte, which allowed the corrosion reaction to proceed. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Improvement to the Corrosion Resistance of Ti-Based Implants Using Hydrothermally Synthesized Nanostructured Anatase Coatings

    Directory of Open Access Journals (Sweden)

    Martina Lorenzetti

    2014-01-01

    Full Text Available The electrochemical behavior of polycrystalline TiO2 anatase coatings prepared by a one-step hydrothermal synthesis on commercially pure (CP Ti grade 2 and a Ti13Nb13Zr alloy for bone implants was investigated in Hank’s solution at 37.5 °C. The aim was to verify to what extent the in-situ-grown anatase improved the behavior of the substrate in comparison to the bare substrates. Tafel-plot extrapolations from the potentiodynamic curves revealed a substantial improvement in the corrosion potentials for the anatase coatings. Moreover, the coatings grown on titanium also exhibited lower corrosion-current densities, indicating a longer survival of the implant. The results were explained by considering the effects of crystal morphology, coating thickness and porosity. Evidence for the existing porosity was obtained from corrosion and nano-indentation tests. The overall results indicated that the hydrothermally prepared anatase coatings, with the appropriate morphology and surface properties, have attractive prospects for use in medical devices, since better corrosion protection of the implant can be expected.

  9. Hot Corrosion Behavior of Cold-sprayed CoNiCrAlY Coating in Na2SO4 Salt

    Directory of Open Access Journals (Sweden)

    ZHANG Lin-wei

    2016-11-01

    Full Text Available CoNiCrAlY coatings were prepared by cold spray process. After deposition, the pre-oxidation treatment of the coating was performed by vacuum heat-treatment. The microstructure and phase constituent of coating were characterized by XRD, SEM and EDS. The hot corrosion behavior of as-sprayed and pre-oxidized CoNiCrAlY coatings in molten Na2SO4 at 900℃ was also studied. The results show that the as-sprayed coating presents a dense structure with low porosity (less than 0.28%, volume fraction and low oxygen content (0.12%, mass fraction. Vacuum pre-oxidation treatment forms a continuous and dense α-Al2O3 layer on the coating surface, with an average thickness of about 0.26μm. As-sprayed and pre-oxidized coatings can protect the substrate from hot corrosion due to the formation of a continuous and dense α-Al2O3 layer. Moreover, the vacuum pre-oxidation treatment can alleviate the diffusion of S and O into coating, and thus the hot corrosion resistance of coating is improved. The damage of hot corrosion plays a more important role than high temperature oxidation. When corrosion in single Na2SO4 molten salt with the same temperature, the consumption speed of Al is two times of that in high temperate oxidation

  10. Emerging Nanotechnology-based Corrosion Control Coatings

    Science.gov (United States)

    2009-02-01

    Al2O3, Fe3O4, Ce (NO3)3, etc. wang Y., et al, Wear, 260, 976-983, 2006. • Epoxy systems with dispersed polyaniline nanoparticles Wessling, B and...triglyceride plus corrosion inhibitor. Koene, B., et al, Proc. Self-healing Conf. 2007 Phenolic varnish plus corrosion inhibitors Stephenson, L, et al US...interactions of nano-sized chemicals Increased surface-to-volume ratio of nanoparticles may result in: -Ingestion through cell membrane -Sensitivity to

  11. Nanotechnology based surface treatments for corrosion protection and deposit control of power plant equipment. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-15

    Nanotechnology can provide possibilities for obtaining new valuable information regarding performance and corrosion protection in power plants. In general the desired performance of the contact surfaces is an easy-to-release effect. This is in order to prolong the time interval between cleaning periods or make the cleaning procedures easier and less expensive. Corrosion protection is also desired in order to extend the life time of various parts in the power plants and thus optimize the energy output and overall efficiency of the plant. Functional sol-gel coating based on nanotechnology is tested in a variety of conditions. Applications of functional sol-gel coatings were performed in the condenser and on seven air preheaters at Fynsvaerket, Odense, with corrosion protection as the main issue. Coatings with easy-to-clean effects were tested in the Flue Gas Desulphurization plant at Nordjyllandsvaerket, Aalborg, with the aim of reducing gipsum deposit. Thermo stabilized coatings were tested on tube bundles between in the passage from the 1st to 2end pass and on the wall between 1st and 2end pass at Amagervaerket, Copenhagen, and in the boiler at Haderslev CHP plant. The objective of this test were reducing deposits and increasing corrosion protection. The tested coatings were commercial available coatings and coatings developed in this project. Visual inspections have been performed of all applications except at Nordjyllandsvaerket. Corrosion assessment has been done at DTU - Mechanical Engineering. The results range from no difference between coated and uncoated areas to some improvements. At Amagervaerket the visual assessment showed in general a positive effect with a sol-gel hybrid system and a commercial system regarding removal of deposits. The visual assessment of the air preheaters at Fynsvaerket indicates reduced deposits on a sol-gel nanocomposite coated air preheater compared to an uncoated air preheater. (Author)

  12. A new strategy for improvement of the corrosion resistance of a green cerium conversion coating through thermal treatment procedure before and after application of epoxy coating

    Energy Technology Data Exchange (ETDEWEB)

    Mahidashti, Z. [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Shahrabi, T., E-mail: tshahrabi34@modares.ac.ir [Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), P.O. 16765-654, Tehran (Iran, Islamic Republic of)

    2016-12-30

    Highlights: • The Ce conversion coating was post-heated at various conditions. • The corrosion resistance of post-heated Ce films was evaluated. • A crack free and denser Ce film were obtained after post-heating. • The corrosion resistance of Ce film noticeably increased. • Post-heated Ce film resulted better protection performance of epoxy coating. - Abstract: The effect of post-heating of CeCC on its surface morphology and chemistry has been studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and contact angle (CA) measurements. The corrosion protection performance of the coatings was investigated by electrochemical impedance spectroscopy (EIS). The effect of thermal treatment of CeCC on the corrosion protection performance of epoxy coating was investigated by EIS. Results showed that the heat treatment of Ce film noticeably improved its corrosion resistance and adhesion properties compared to that of untreated samples. The CeCC deposited on the steel substrate at room temperature had a highly cracked structure, while the amount of micro-cracks significantly reduced after post-heating procedure. Results obtained from EIS analysis confirmed the effect of post-heating of CeCC on its corrosion protection performance enhancement. The increase of post-heating temperature and time up to 140 °C and 3 h led to better results.

  13. Corrosion and coating defects on buried pipelines under CP: Excavations data collection and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Karcher, Sebastien; Campaignolle, Xavier; Masson, Bernard; Meyer, Michel [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33 93211 Saint Denis La Plaine (France)

    2004-07-01

    Onshore gas transmission pipelines are conjointly protected against external corrosion by an organic coating and by cathodic protection (CP). Owing to particular defects or coating aging in the long term in ground, the protective efficiency of this dual system may be impaired. Consequently, external corrosion may develop and, eventually, threaten the integrity of the line if not detected and mitigated in time. To ensure continued protection of its lines against external corrosion, Gaz de France carries out, routinely, several maintenance and monitoring activities on the CP system. In addition, above ground surveys allow a better assessment of possible coating faults. However, it is necessary to continuously improve the reliability of the corrosion prediction to optimize the maintenance of pipelines. When indications and measurements from any mean of inspection (in-line inspection or above ground surveys) lead to suspect the presence of any significant metal defect, an excavation of the concerned pipe section is performed. At each excavation location, many parameters are collected to document the existing conditions of coating and steel. If sufficiently extended and reliable, this information may help to understand the root causes for development of corrosion. Eventually, thorough analysis of field data resulting either from inspection or from maintenance operations could lead to corrosion prediction. Since the volume of these data is large, reliability and consistency of information is absolutely required. Gaz de France has implemented a systematic data collection procedure on excavation sites, together with data analysis through a range of treatment methods. Data on more than 1400 excavations, pertaining to a set of different selected pipelines, have been collected in a single database. The later contains data such as pipelines characteristics, local cathodic protection parameters at the time of excavation, coating defect description if any, characterization of

  14. Evaluation of electrodeposited Mn-Co protective coatings on Crofer 22 APU steel

    DEFF Research Database (Denmark)

    Molin, Sebastian

    2017-01-01

    Interconnects used in Solid Oxide Cells stacks require protective coatings to lower their parabolic rate constant and block chromium evaporation (on the air side). In this work four different protective coatings on steel are evaluated for their high temperature corrosion resistance and electrical......-ray diffractomettry. Based on the results, influence of the Co/Mn ratio on the resulting corrosion properties are discussed. Parabolic rate constant of the coated samples is the lowest for the MnCo sample, whereas electrical resistance is the lowest for the Co sample, which has a corrosion rate similar to the not...

  15. Trends in the automotive paint industry for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Blandin, Nathalie; Brunat, William [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Neuhaus, Ralf [PPG Industries Lacke GmbH, Stackenbergstrasse 34, D-42329 Wuppertal (Germany); Sibille, Ettore [PPG Industries Italia, Via Serra11, I-15028 Quattordio (Italy)

    2004-07-01

    Since many years ED-paints are protecting car bodies against corrosion. Currently the automotive paint industry is faced with increasing demands of higher levels of corrosion protection and also requests to comply with new environmental regulations and economical pressures. Some key factors that contributed significantly towards the improvement of corrosion protection systems are: - New generations of lead free ED-paints; - Weldable organic thin film for corrosion protection, especially in box cavities and flange areas. The goal of this paper is to show how the various elements of the 'anti-corrosion package' interact. (authors)

  16. Alkaline corrosion properties of laser-clad aluminum/titanium coatings

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Herbreteau, Alexis; Rombouts, Marleen

    2015-01-01

    with supersaturated titanium ( (1 weight per cent), Al3Ti intermetallics and large partially undissolved Ti6Al4V particles. Heat treatment lowered the titanium concentration in the aluminum matrix, changed the shape of the Al3Ti precipitates and increased the degree of dissolution of the Ti6Al4V particles. Corrosion...... testing showed significant localized dissolution of the aluminum matrix. Research limitations/implications – Increased titanium concentration and heat treatment gave improved alkaline corrosion properties. At pH 13.5, the Al3Ti phases were protected, while the aluminum matrix corroded. Practical...... implications – For alkaline corrosion-protection of aluminum in the automobile industry, titanium might be useful at pH values below 13.5 or by using other coating techniques. Originality/value – This is the first study testing the use of titanium as a protective element of aluminum in stringent alkaline...

  17. Embedded reference electrodes for corrosion potential monitoring, electrochemical characterization, and controlled-potential cathodic protection

    Science.gov (United States)

    Merten, Bobbi Jo Elizabeth

    A thin wire Ag/AgCl reference electrode was prepared using 50 mum Ag wire in dilute FeCl3. The wire was embedded beneath the polyurethane topcoat of two sacrificial coating systems to monitor their corrosion potential. This is the first report of a reference electrode embedded between organic coating layers to monitor substrate health. The embedded reference electrode (ERE) successfully monitored the corrosion potential of Mg primer on AA 2024-T3 for 800 days of constant immersion in dilute Harrison's solution. Zn primer on steel had low accuracy in comparison. This is in part due to short circuiting by Zn oxidation products, which are much more conductive than Mg corrosion products. Data interpretation was improved through statistical analysis. On average, ERE corrosion potentials are 0.1 to 0.2 V and 0.2 to 0.3 V more positive than a saturated calomel electrode (SCE) in solution for AA 2024-T3 and steel coating systems, respectively. Further research may confirm that ERE obtains corrosion potential information not possible by an exterior, conventional reference electrode. The ERE is stable under polarization. AA 2024-T3 was polarized to -0.95 V vs ERE to emulate controlled potential cathodic protection (CPCP) applications. Polarizations of -0.75 V vs ERE are recommended for future experiments to minimize cathodic delamination. The ERE was utilized to analyze coating mixtures of lithium carbonate, magnesium nitrate, and Mg metal on AA2024-T3. Corrosion potential, low frequency impedance by electrochemical impedance spectroscopy (EIS), and noise resistance by electrochemical noise method (ENM) were reported. Coating performance ranking is consistent with standard electrochemical characterization and visual analyses. The results suggest anti-corrosion resistance superior to a standard Mg primer following 1600 hours of B117 salt spray. Both lithium carbonate and magnesium nitrate are necessary to achieve corrosion protection. Unique corrosion protective coatings for

  18. Corrosion Protection Systems and Fatigue Corrosion in Offshore Wind Structures: Current Status and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Seth J. Price

    2017-02-01

    Full Text Available Concerns over reducing CO2 emissions associated with the burning of fossil fuels in combination with an increase in worldwide energy demands is leading to increased development of renewable energies such as wind. The installation of offshore wind power structures (OWS is one of the most promising approaches for the production of renewable energy. However, corrosion and fatigue damage in marine and offshore environments are major causes of primary steel strength degradation in OWS. Corrosion can reduce the thickness of structural components which may lead towards fatigue crack initiation and buckling. These failure mechanisms affect tower service life and may result in catastrophic structural failure. Additionally, environmental pollution stemming from corrosion’s by-products is possible. As a result, large financial investments are made yearly for both the prevention and recovery of these drawbacks. The corrosion rate of an OWS is dependent on different characteristics of attack which are influenced by access to oxygen and humidity. Structural degradation can occur due to chemical attack, abrasive action of waves, and microorganism attacks. Inspired by technological and scientific advances in recent years, the purpose of this paper is to discuss the current protective coating system technologies used to protect OWS as well as future perspectives.

  19. Protection by high velocity thermal spraying coatings on thick walled permanent and interim store components for the diminution of repairs, corrosion and costs 'SHARK'. Overview at the end of the project; Schutz durch Hochgeschwindigkeitsflammspritzschichten auf dickwandigen End- und Zwischenlagerbauteilen zur Reduktion von Reparaturen, Korrosion und Kosten 'SHARK'. Ein Ueberblick zum Abschluss des Projektes

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Sabine; Hassel, Thomas; Bach, Friedrich-Wilhelm [Unterwassertechnikum Hannover, Garbsen (Germany). Inst. fuer Werkstoffkunde; Steinwarz, Wolfgang; Dyllong, Nobert; Tragsdorf, Inga Maren [Siempelkamp Nukleartechnik GmbH, Krefeld (Germany)

    2012-04-15

    The corrosion protection of the internal space of thick-walled interim and permanent storage facility components, such as Castor {sup copyright} containers, are ensured nowadays by a galvanic nickel layer. The method has proved itself and protects the base material of the containers at the underwater loading in the Nuclear power station from a corrosive attack. Although, the galvanic nickel plating is a relatively time consuming method, it lasts for several days for each container, and is with a layer thickness of 1,000 {mu}m also expensive. To develop an alternative, faster and more economical method, a BMBF research project named - 'SHARK - protection by high velocity thermal spraying layers on thick-walled permanent and interim store components for the diminution of repairs, corrosion and costs' in cooperation between Siempelkamp Nukleartechnik GmbH and the Institute of Materials Science of the Leibniz University of Hanover was established to investigate the suitability of the high velocity oxy fuel spraying technology (HVOF) for the corrosion protective coating of thickwalled interim and permanent storage facility components. Since the permanent storage depot components are manufactured from cast iron with globular graphite, this material was exclusively used as a base material in this project. The evaluation of the economical features of the application of different nickel base spraying materials on cast iron substratum was in focus, as well as the scientific characterization of the coating systems with regard to the corrosion protective properties. Furthermore, the feasibility of the transfer of the laboratory results on a large industrial setup as well as a general suitability of the coating process for a required repair procedure was to be investigated. The preliminary examination program identified chromium containing spraying materials as successful. Results of the preliminary examination program have been used for investigations with the CASOIK

  20. Corrosion and Protection of Metal in the Seawater Desalination

    Science.gov (United States)

    Hou, Xiangyu; Gao, Lili; Cui, Zhendong; Yin, Jianhua

    2018-01-01

    Seawater desalination develops rapid for it can solve water scarcity efficiently. However, corrosion problem in the seawater desalination system is more serious than that in normal water. So, it is important to pay attention to the corrosion and protection of metal in seawater desalination. The corrosion characteristics and corrosion types of metal in the seawater desalination system are introduced in this paper; In addition, corrosion protect methods and main influencing factors are stated, the latest new technologies about anti-corrosion with quantum energy assisted and magnetic inhibitor are presented.

  1. Adsorption of alginate and albumin on aluminum coatings inhibits adhesion of Escherichia coli and enhances the anti-corrosion performances of the coatings

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaoyan; Liu, Yi; Huang, Jing; Chen, Xiuyong; Ren, Kun; Li, Hua, E-mail: lihua@nimte.ac.cn

    2015-03-30

    Graphical abstract: - Highlights: • Adsorption behaviors of alginate and albumin on Al coatings were investigated at molecular level. • The adsorption inhibits effectively the colonization of Escherichia coli bacteria. • The adsorption alters the wettability of the Al coatings. • The conditioning layer enhances anti-corrosion performances of the Al coatings. - Abstract: Thermal-sprayed aluminum coatings have been extensively used as protective layers against corrosion for steel structures in the marine environment. The corrosion usually deteriorates from marine biofouling, yet the mechanism of accelerated corrosion of the coatings remains elusive. As the first stage participating in biofouling process, adsorption of molecules plays critical roles in mediating formation of biofilm. Here, we report at molecular level the adsorption behaviors of albumin and marine polysaccharide on arc-sprayed aluminum coatings and their influence on adhesion of Escherichia coli. The adsorption of alginate and albumin was characterized by infrared spectra analyses and atomic force microscopic observation. The adsorption inhibits effectively adhesion of the bacteria. Further investigation indicates that alginate/albumin altered the hydrophilicity/hydrophobicity of the coatings instead of impacting the survival of the bacteria to decline their adhesion. The conditioning layer composed of the molecules enhances anti-corrosion performances of the coatings.

  2. Electrosynthesis of Polyaniline-TiO2 Nanocomposite Films on Aluminum Alloy 3004 Surface and its Corrosion Protection Performance

    Directory of Open Access Journals (Sweden)

    M. Shabani-Nooshabadi

    2013-03-01

    Full Text Available The direct synthesis of polyaniline-TiO2 nanocomposite coatings on aluminum alloy 3004 (AA3004 surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by FT-IR, SEM-EDX, SEM and AFM. Optical absorption spectroscopy reveals the formation of the emeraldine oxidation state form of polyaniline-TiO2 nanocomposite. The corrosion performances of polyaniline-TiO2 nanocomposite coatings were investigated in 3.5% NaCl solution by Tafel polarization and Electrochemical Impedance Spectroscopy (EIS methods. The corrosion rate of polyaniline-TiO2 nanocomposite coating on AA3004 was found ∼260 times lower than bare AA3004 and corrosion potentials of these coatings have shifted to more positive potentials (105 mV. The results of this study clearly ascertain that the polyaniline-TiO2 nanocomposite coating has outstanding potential to protect the AA3004 against corrosion in a chloride environment.

  3. Protective coatings for commercial particulates

    DEFF Research Database (Denmark)

    Kindl, B.; Teng, Y.H.; Liu, Y.L.

    1994-01-01

    SiC/Al composites are in large-scale production with Al-Si alloy matrices. The same composites with pure Al or low Si matrices need diffusion barriers on the SiC reinforcement to control the interfacial reaction. The present paper describes various approaches taken to obtain protective coatings...... of alumina and zirconia on SiC particulates by sol-gel techniques. Aqueous and organic precursors have been used. The extent of the reaction, i.e., the Si and Al4C3 content in the matrix, was determined by differential thermal analysis and X-ray diffraction. The reaction rates of some coated particulates...... in liquid Al are decreased by as much as one order of magnitude during the first 15 min of immersion. Pretreatments of the SiC surface, the composition and thickness of the coating interphase and heat treatments of the coated materials have been studied, and are discussed in relation to their effect...

  4. Corrosion Protection of Launch Infrastructure and Hardware Through the Space Shuttle Program

    Science.gov (United States)

    Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, has been a challenging and costly problem that has affected NASA's launch operations since the inception of the Space Program. Corrosion studies began at NASA's Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term protective coatings for the atmospheric protection of carbon steel. NASA's KSC Beachside Corrosion Test Site, which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive natural conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocket boosters. In the years that followed, numerous efforts at KSC identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosiye environment at the launch pads. Knowledge on materials degradation, obtained by facing the highly corrosive conditions of the Space Shuttle launch environment, as well as limitations imposed by the environmental impact of corrosion control, have led researchers at NASA's Corrosion Technology Laboratory to establish a new technology development capability in the area of corrosion prevention, detection, and mitigation at KSC that is included as one of the "highest priority" technologies identified by NASA's integrated technology roadmap. A historical perspective highlighting the challenges encountered in protecting launch infrastructure and hardware from corrosion during the life of the Space Shuttle program and the new technological advances that have resulted from facing the unique and highly corrosive conditions of the Space Shuttle launch environment will be presented.

  5. Coating of Steel by Alkyd Resin Reinforced with Al2O3 Nanoparticles to Improve Corrosion Resistance

    Science.gov (United States)

    Kordzangeneh, Shirin; Naghibi, Sanaz; Esmaeili, Hamideh

    2018-01-01

    In this study, an alkyd/Al2O3 nanocomposite coating was prepared and applied on a stainless steel substrate. The Al2O3 nanoparticles (NPs) with different weight ratios (1, 2, and 3 wt.%) were added to the alkyd resin and coated on the substrate via dip-coating technique. Then, the dispersion of NPs in the coating film was investigated using scanning electron microscopy (SEM) and scanning probe microscopy (SPM). The coating thickness estimated by SEM was 20 μm. The corrosion behavior of the coating was examined through the Tafel polarization and salt spray tests. The results showed that the addition of Al2O3 NPs up to 2 wt.% will result in a dense and homogeneous coating which protects the substrate leading to lower corrosion current density from 9.2 × 10-6 to 1.65×10-9 A/cm2 compared with the uncoated stainless steel.

  6. Examination of Hybrid Metal Coatings for Mitigation of Fission Product Release and Corrosion Protection of LWR SiC/SiC

    Energy Technology Data Exchange (ETDEWEB)

    Ang, Caen K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burns, Joseph R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    There is a need to increase the safety margins of current and future light water reactors (LWRs) due to the unfortunate events at Fukushima Daiichi Nuclear Plant. Safety is crucial to restore public confidence in nuclear energy, acknowledged as an economical, high-­density energy solution to climate change. The development of accident-­tolerant fuel (ATF) concepts is crucial to this endeavor. The objective of ATF is to delay the consequences of accident progression, being inset in high temperature steam and maintaining high thermomechanical strength for radionuclide retention. The use of advanced SiCf-­SiC composite as a substitute for zircaloy-­based cladding is being considered. However, at normal operations, SiC is vulnerable to the reactor coolant and may corrode at an unacceptable rate. As a ceramic-­matrix composite material, it is likely to undergo microcracking operation, which may compromise the ability to contain gaseous fission products. A proposed solution to both issues is the application of mitigation coatings for use in normal operations. At Oak Ridge National Laboratory (ORNL), three coating technologies have been investigated with industry collaborators and vendors. These are electrochemical deposition, cathodic arc physical vapor deposition (PVD hereafter) and vacuum plasma spray (VPS). The objective of this document is to summarize these processing technologies, the resultant as-­processed microstructures and properties of the coatings. In all processes, substrate constraint resulted in substantial tensile stresses within the coating layer. Each technology must mitigate this tensile stress. Electrochemical coatings use chromium as the coolant facing material, and are deposited on a nickel or carbon “bond coat”. This is economical but suffers microcracking in the chromium layer. PVD-­based coatings use chromium and titanium in both metallic form and nitrides, and can be deposited defense-­in-­depth as multilayers. This vapor method

  7. Structural steel coatings for corrosion mitigation.

    Science.gov (United States)

    2010-10-01

    Task 1 of this project was to survey the performance of coating systems for steel bridges in Missouri and to evaluate coating and : recoating practices. Task 1 was led under the direction of Dr. Glenn Washer from the University of Missouri located in...

  8. Corrosion protection properties and interfacial adhesion mechanism of an epoxy/polyamide coating applied on the steel surface decorated with cerium oxide nanofilm: Complementary experimental, molecular dynamics (MD) and first principle quantum mechanics (QM) simulation methods

    Science.gov (United States)

    Bahlakeh, Ghasem; Ramezanzadeh, Bahram; Saeb, Mohammad Reza; Terryn, Herman; Ghaffari, Mehdi

    2017-10-01

    The effect of cerium oxide treatment on the corrosion protection properties and interfacial interaction of steel/epoxy was studied by electrochemical impedance spectroscopy, (EIS) classical molecular dynamics (MD) and first principle quantum mechanics (QM) simulation methods X-ray photoelectron spectroscopy (XPS) was used to verify the chemical composition of the Ce film deposited on the steel. To probe the role of the curing agent in epoxy adsorption, computations were compared for an epoxy, aminoamide and aminoamide modified epoxy. Moreover, to study the influence of water on interfacial interactions the MD simulations were executed for poly (aminoamide)-cured epoxy resin in contact with the different crystallographic cerium dioxide (ceria, CeO2) surfaces including (100), (110), and (111) in the presence of water molecules. It was found that aminoamide-cured epoxy material was strongly adhered to all types of CeO2 substrates, so that binding to ceria surfaces followed the decreasing order CeO2 (111) > CeO2 (100) > CeO2 (110) in both dry and wet environments. Calculation of interaction energies noticed an enhanced adhesion to metal surface due to aminoamide curing of epoxy resin; where facets (100) and (111) revealed electrostatic and Lewis acid-base interactions, while an additional hydrogen bonding interaction was identified for CeO2 (110). Overall, MD simulations suggested decrement of adhesion to CeO2 in wet environment compared to dry conditions. Additionally, contact angle, pull-off test, cathodic delamination and salt spray analyses were used to confirm the simulation results. The experimental results in line with modeling results revealed that Ce layer deposited on steel enhanced substrate surface free energy, work of adhesion, and interfacial adhesion strength of the epoxy coating. Furthermore, decrement of adhesion of epoxy to CeO2 in presence of water was affirmed by experimental results. EIS results revealed remarkable enhancement of the corrosion

  9. Cyclotriphosphazene and TiO2 reinforced nanocomposite coated on mild steel plates for antibacterial and corrosion resistance applications

    Science.gov (United States)

    Krishnadevi, Krishnamoorthy; Selvaraj, Vaithilingam

    2016-03-01

    The mild steel surface has been modified to impart anticorrosion and antibacterial properties through a dip coating method followed by thermal curing of a mixture containing amine terminated cyclotriphosphazene and functionalized titanium dioxide nanoparticles reinforced benzoxazine based cyanate ester composite (ATCP/FTiO2/Bz-CE). The corrosion resistance behavior of coating material has been investigated by electrochemical and antibacterial studies by disc diffusion method. The nanocomposites coated mild steels have displayed a good chemical stability over long immersion in a corrosive environment. The protection efficiency has found to be high for ATCP/FTiO2/Bz-CE composites, which can be used in microelectronics and marine applications.

  10. Addressing stress corrosion cracking on multi layer pipeline coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Scott B.; Marr, James E. [Tuboscope Pipeline Services, Houston, TX (United States); Willmot, Martyn [Jotun Group (Norway); Norman, David [David Norman Corrosion Control, Cornwall (United Kingdom); Khera, Ashish [Allied Engineering, Portland, ME (United States)

    2005-07-01

    Stress corrosion cracking (SCC) is now recognized by operators worldwide as a significant threat to the safe operation of their pipeline systems. Gas, oil, and refined products lines have all been susceptible to this form of environmentally assisted cracking. As a result, operators and regulators have been incorporating data related to the development and prevalence of SCC into their risk management systems in order that they may effectively address this time-dependant threat. The National Association of Corrosion Engineers (NACE) published the first structured methodology for stress corrosion cracking direct assessment (SCCDA) in 2004 (RP0204-2004). Operators are now beginning to apply the methods outlined in the standard to assess their systems. Research and industry experience have shown that various pipeline coating systems can be more or less effective in preventing the formation and growth of SCC. Newer pipeline coatings, such as multi layer epoxy/extruded polyolefin systems have been widely regarded as effective coating systems to address the threat posed by SCC when they are properly applied. New field studies performed on a pipeline coated with a three layer epoxy/polyethylene system have raised the possibility that operators utilizing these types of coatings may need to reassess how they manage the SCC threat. (author)

  11. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Guo, Changhong; Jiang, Guirong [College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shen, Dejiu, E-mail: DejiuShen@163.com [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2016-08-15

    Highlights: • Corrosion behaviors of a PEO coating was investigated after the salt spray test. • Corrosion products have significant effects on corrosion behaviors of the coating. • An electrochemical corrosion model is proposed. - Abstract: The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  12. KCl-Induced High-Temperature Corrosion Behavior of HVAF-Sprayed Ni-Based Coatings in Ambient Air

    Science.gov (United States)

    Jafari, Reza; Sadeghimeresht, Esmaeil; Farahani, Taghi Shahrabi; Huhtakangas, Matti; Markocsan, Nicolaie; Joshi, Shrikant

    2018-01-01

    KCl-induced high-temperature corrosion behavior of four HVAF-sprayed Ni-based coatings (Ni21Cr, Ni5Al, Ni21Cr7Al1Y and Ni21Cr9Mo) under KCl deposit has been investigated in ambient air at 600 °C up to 168 h. The coatings were deposited onto 16Mo3 steel—a widely used boiler tube material. Uncoated substrate, 304L and Sanicro 25 were used as reference materials in the test environment. SEM/EDS and XRD techniques were utilized to characterize the as-sprayed and exposed samples. The results showed that the small addition of KCl significantly accelerated degradation to the coatings. All coatings provided better corrosion resistance compared to the reference materials. The alumina-forming Ni5Al coating under KCl deposit was capable of forming a more protective oxide scale compared to the chromia-forming coatings as penetration of Cl through diffusion paths was hindered. Both active corrosion and chromate formation mechanisms were found to be responsible for the corrosion damages. The corrosion resistance of the coatings based on the microstructure analysis and kinetics had the following ranking (from the best to worst): Ni5Al > Ni21Cr > Ni21Cr7Al1Y > Ni21Cr9Mo.

  13. Application of aluminum diffusion coatings to mitigate the KCl-induced high-temperature corrosion

    DEFF Research Database (Denmark)

    Kiamehr, Saeed; Lomholt, T. N.; Dahl, Kristian Vinter

    2017-01-01

    Pack cementation was used to produce Fe1−xAl and Fe2Al5 diffusion coatings on ferritic-martensitic steel P91 and a Ni2Al3 diffusion coating on pure nickel. The performance of diffusion coatings against high-temperature corrosion induced by potassium chloride (KCl) was evaluated by exposing......-ray diffractometry (XRD) before and after the exposures. It was found that all the diffusion coatings formed protective oxides under salt-free exposure in air. Under the salt deposit, Fe1−xAl showed local failure while on large parts of the sample a protective layer had formed. Fe2Al5 was attacked over the entire...

  14. Osseoconductive and Corrosion-Inhibiting Plasma-Sprayed Calcium Phosphate Coatings for Metallic Medical Implants

    Directory of Open Access Journals (Sweden)

    Robert B. Heimann

    2017-11-01

    Full Text Available During the last several decades, research into bioceramic coatings for medical implants has emerged as a hot topic among materials scientists and clinical practitioners alike. In particular, today, calcium phosphate-based bioceramic materials are ubiquitously used in clinical applications to coat the stems of metallic endoprosthetic hips as well as the surfaces of dental root implants. Such implants frequently consist of titanium alloys, CoCrMo alloy, or austenitic surgical stainless steels, and aim at replacing lost body parts or restoring functions to diseased or damaged tissues of the human body. In addition, besides such inherently corrosion-resistant metals, increasingly, biodegradable metals such as magnesium alloys are being researched for osseosynthetic devices and coronary stents both of which are intended to remain in the human body for only a short time. Biocompatible coatings provide not only vital biological functions by supporting osseoconductivity but may serve also to protect the metallic parts of implants from corrosion in the aggressive metabolic environment. Moreover, the essential properties of hydroxylapatite-based bioceramic coatings including their in vitro alteration in contact with simulated body fluids will be addressed in this current review paper. In addition, a paradigmatic shift is suggested towards the development of transition metal-substituted calcium hexa-orthophosphates with the NaSiCON (Na superionic conductor structure to be used for implant coatings with superior degradation resistance in the corrosive body environment and with pronounced ionic conductivity that might be utilized in novel devices for electrical bone growth stimulation.

  15. Corrosion studies of modified organosilane coated magnesium-yttrium alloy in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Xue Dingchuan [College of Engineering, University of Cincinnati, OH 45221 (United States); Tan Zongqing [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States); Schulz, Mark J. [College of Engineering, University of Cincinnati, OH 45221 (United States); Vanooij, William J. [College of Engineering, University of Cincinnati, OH 45221 (United States); ECOSIL Technologies LLC, Fairfield, OH 45014 (United States); Sankar, Jagannathan [Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Yun Yeoheung, E-mail: yyun@ncat.edu [College of Engineering, University of Cincinnati, OH 45221 (United States); Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Dong Zhongyun [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States)

    2012-07-01

    Magnesium (Mg) and its alloys have numerous potential applications as biodegradable implants, but the fast degradation rate of Mg alloys at the initial implanted stage could be a problem. This paper describes the modification of the water-based bis-[triethoxysilyl] ethane (BTSE) silane applied to the surface of magnesium-yttrium (Mg-4Y) to increase its corrosion resistance. Surface characterization by SEM, FTIR, and EDX showed that the hydrolysis and condensation of the silane resulted in a covalent bonding to the Mg-4Y surface. Corrosion behavior of the uncoated and coated Mg-4Y alloy was evaluated in different environments by using a novel self-developed corrosion probe. Based on the electrochemical results of DC polarization and electrochemical impedance spectroscopy (EIS), we conclude that the epoxy-modified BTSE silane coating successfully increases the corrosion resistance at the initial stage of implantation. The corrosion rates in the flesh of dead mice environments such as body cavity and subcutaneous tissue of the mice were lower than the corrosion rates in in vitro environments. - Highlights: Black-Right-Pointing-Pointer Modified silane was used on Mg-4Y for biological applications. Black-Right-Pointing-Pointer Modified silane-treated Mg-4Y increased its corrosion resistance in both In Vitro and In Vivo environments. Black-Right-Pointing-Pointer In Vitro testing environment is not consistent with In Vivo animal environment. Black-Right-Pointing-Pointer The modified silane mixture protecting mechanisms and its biocompatibility were discussed. Black-Right-Pointing-Pointer A novel three-electrode corrosion-monitoring probe was developed for realizing this work's In Vivo testing goals.

  16. Plasma polymerized hexamethyldisiloxane thin films for corrosion protection

    Science.gov (United States)

    Saloum, S.; Alkhaled, B.; Alsadat, W.; Kakhia, M.; Shaker, S. A.

    2018-01-01

    This study focused on the corrosion protection performance of plasma polymerized HMDSO thin films in two different corrosive medias, 0.3M NaCl and 0.3M H2SO4. The pp-HMDSO thin films were deposited on steel substrates for electrochemical tests using the potentiodynamic polarization technique, they were deposited also on aluminum and silicon substrates to investigate their resistance to corrosion, through the analysis of the degradation of microhardness and morphology, respectively, after immersion of the substrates for one week in the corrosive media. The results showed promising corrosion protection properties of the pp-HMDSO thin films.

  17. Electrochemical Characterisation of Filiform Corrosion on Aluminium Rolled Products

    NARCIS (Netherlands)

    Huisert, M.

    2001-01-01

    When aluminium is protected by an organic coating a special form of corrosion can occur underneath the organic coating; filiform corrosion. This form of corrosion manifests itself as threadlike filaments under the coating, it causes local delamination of the coating and the coating cannot protect

  18. Polypyrrole electrochemistry : Environmentally friendly corrosion protection of steel: (im)possibilities

    NARCIS (Netherlands)

    Hamer, W.J.

    2005-01-01

    Chromate compounds have been widely used to improve the corrosion protection of galvanised steel and aluminium objects in the past decades. The hexavalent chromium in chromate enhances the adherence of coatings to galvanised steel and aluminium. Additionally, if the passive layers on these materials

  19. Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

    Science.gov (United States)

    Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

    2016-11-01

    In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. 49 CFR 195.561 - When must I inspect pipe coating used for external corrosion control?

    Science.gov (United States)

    2010-10-01

    ... corrosion control? 195.561 Section 195.561 Transportation Other Regulations Relating to Transportation...) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Corrosion Control § 195.561 When must I inspect pipe coating used for external corrosion control? (a) You must inspect all external pipe coating...

  1. Release of cerium dibutylphosphate corrosion inhibitors from highly filled epoxy coating systems

    NARCIS (Netherlands)

    Soestbergen, M. van; Baukh, V.; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G.

    2014-01-01

    Carcinogenic chromates are phased out as corrosion inhibitors in organic coatings, and are replaced by benign alternatives. Cerium-based compounds are excellent corrosion inhibitors in an aqueous environment. However, whether they are effective as corrosion inhibitor in an organic coating also

  2. Effect of Mg content on microstructure and corrosion behavior of hot dipped Zn–Al–Mg coatings

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Caizhen; Lv, Haibing [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Zhu, Tianping [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Zheng, Wanguo [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Yuan, Xiaodong, E-mail: xdyuan@caep.cn [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Gao, Wei, E-mail: w.gao@auckland.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand)

    2016-06-15

    In this article, Zn–Al–Mg coatings were prepared by hot dipping method. The surface morphology, cross–section microstructure, microhardness, composition, corrosion behaviour of ZAM coatings were investigated by using X–ray diffraction (XRD), Optical microscope, Environmental scanning electron microscopy equipped with EDS (FESEM–EDS), Microhardness tester and Electrochemical analysis respectively. Corrosion test was also performed in a standard salt fog spray chamber. Microstructure studies indicates that Zn grain size was refined and eutectic areas at Zn grain boundary areas increased with increasing Mg content. ZA5M1.5 and ZA5M2 coatings have two distinct layers. Mg tends to exist in the outer layer while Al is in the inner layer. The inner layer is composed of Al{sub 5}Fe{sub 2}Zn{sub 0.4} intermetallic, which may to contribute to the microhardness. The outer layer is Zn grains surrounded by Zn–Mg etutectics, which may improve the corrosion resistance. The microhardness is more than 700 HV{sub 50g} for Al-rich layer and around 151 HV{sub 25g} for Mg-rich layer. The improved corrosion resistance of Zn–5%Al-1.5%Mg coating comes from the corrosion product of flocculent type simonkolleite, which prolongs the micro-path and impedes the movement of O{sub 2} and H{sub 2}O, ultimately retards the overall corrosion process. - Highlights: • Two-layer structured Zn–Al–Mg coatings were prepared by hot dipping method. • Mg exists in the outer layer while Al exists in the inner layer of Zn–Al–Mg coating. • Zn–Al–Mg coating has better protective ability than Zn and Zn–Al coatings. • The Mg-modified simonkolleite is the reason of the enhanced corrosion resistance.

  3. Microtribological and electrochemical corrosion behaviors of polydopamine coating on APTS-SAM modified Si substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ou Junfei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100080 (China); Wang Jinqing, E-mail: jqwang@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu Sheng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100080 (China); Zhou Jinfang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Ren Sili, E-mail: slren@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang Shengrong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2009-11-15

    A polydopamine coating (coded as PDAc) was prepared successfully on a Si substrate through a two-step process. Briefly, to improve the adhesion of PDAc on the Si substrate, a self-assembled monolayer of 3-aminopropyl triethoxysilane (coded as APTS-SAM) was firstly generated on the bare Si wafer. Thereafter, the PDAc with different thickness was fabricated through the chemical adsorption and autopolymerization of the dopamine hydrochloride on the APTS-SAM coated Si substrate. The formation of PDAc on the APTS-SAM modified Si substrate was proved by the characterizations of contact angle measurement, attenuated total reflectance Fourier transform infrared (ATR-FTIR) analysis, and X-ray photoelectron spectroscope (XPS), etc. The ellipsometric thickness measurement and atomic force microscopy (AFM) image analysis showed that the PDAc became thicker and rougher with the deposition time prolongation. Microtribological study showed that the thickness and roughness of the PDAc played a significant role in the tribological properties. In comparison with the bare Si substrate, the PDAc with thinner thickness possessed lower friction and was anticipated to be used as protecting coating in the field of boundary lubrication. The electrochemical corrosion behaviors of the prepared PDAc were investigated using the electrochemical station and a low corrosion current density was revealed, implying that the PDAc had good anti-corrosion capability and might find potential applications in the field of corrosion resistance.

  4. Enhanced Corrosion Resistance of PVD-CrN Coatings by ALD Sealing Layers

    Science.gov (United States)

    Wan; Zhang, Teng Fei; Ding, Ji Cheng; Kim, Chang-Min; Park, So-Won; Yang, Yang; Kim, Kwang-Ho; Kwon, Se-Hun

    2017-04-01

    Multilayered hard coatings with a CrN matrix and an Al2O3, TiO2, or nanolaminate-Al2O3/TiO2 sealing layer were designed by a hybrid deposition process combined with physical vapor deposition (PVD) and atomic layer deposition (ALD). The strategy was to utilize ALD thin films as pinhole-free barriers to seal the intrinsic defects to protect the CrN matrix. The influences of the different sealing layers added in the coatings on the microstructure, surface roughness, and corrosion behaviors were investigated. The results indicated that the sealing layer added by ALD significantly decreased the average grain size and improved the corrosion resistance of the CrN coatings. The insertion of the nanolaminate-Al2O3/TiO2 sealing layers resulted in a further increase in corrosion resistance, which was attributed to the synergistic effect of Al2O3 and TiO2, both acting as excellent passivation barriers to the diffusion of corrosive substances.

  5. Microtribological and electrochemical corrosion behaviors of polydopamine coating on APTS-SAM modified Si substrate

    Science.gov (United States)

    Ou, Junfei; Wang, Jinqing; Liu, Sheng; Zhou, Jinfang; Ren, Sili; Yang, Shengrong

    2009-11-01

    A polydopamine coating (coded as PDAc) was prepared successfully on a Si substrate through a two-step process. Briefly, to improve the adhesion of PDAc on the Si substrate, a self-assembled monolayer of 3-aminopropyl triethoxysilane (coded as APTS-SAM) was firstly generated on the bare Si wafer. Thereafter, the PDAc with different thickness was fabricated through the chemical adsorption and autopolymerization of the dopamine hydrochloride on the APTS-SAM coated Si substrate. The formation of PDAc on the APTS-SAM modified Si substrate was proved by the characterizations of contact angle measurement, attenuated total reflectance Fourier transform infrared (ATR-FTIR) analysis, and X-ray photoelectron spectroscope (XPS), etc. The ellipsometric thickness measurement and atomic force microscopy (AFM) image analysis showed that the PDAc became thicker and rougher with the deposition time prolongation. Microtribological study showed that the thickness and roughness of the PDAc played a significant role in the tribological properties. In comparison with the bare Si substrate, the PDAc with thinner thickness possessed lower friction and was anticipated to be used as protecting coating in the field of boundary lubrication. The electrochemical corrosion behaviors of the prepared PDAc were investigated using the electrochemical station and a low corrosion current density was revealed, implying that the PDAc had good anti-corrosion capability and might find potential applications in the field of corrosion resistance.

  6. Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies

    Energy Technology Data Exchange (ETDEWEB)

    Brachetti S, S. B. [Instituto Tecnologico de Ciudad Madero, Av. 1o. de Mayo y Sor Juana I. de la Cruz, Col. Los Mangos, 89440 Ciudad Madero, Tanaulipas (Mexico); Dominguez C, M. A.; Torres H, A. M.; Onofre B, E. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Altamira, Carretera Tampico-Puerto Industrial Altamira Km. 14.5, 89600 Altamira, Tamaulipas (Mexico); De la Cruz H, W., E-mail: mdominguezc@ipn.mx [UNAM, Centro de Nanociencias y Nanotecnologia, Apdo. Postal 2681, 22800 Ensenada, Baja California (Mexico)

    2014-07-01

    The present work is aimed to investigate the corrosion resistance of rare earth protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO{sub 3}){sub 3} and La(NO{sub 3}){sub 3} solutions by varing parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization. Chemical and morphological characterizations of the surface before and after electrochemical evaluations were performed by X-ray photoelectron spectroscopy and scanning electron microscopy. (Author)

  7. An effective and novel pore sealing agent to enhance the corrosion resistance performance of Al coating in artificial ocean water

    Science.gov (United States)

    Lee, Han-Seung; Singh, Jitendra Kumar; Ismail, Mohamed A.

    2017-01-01

    A new technique was accepted to fill the porosity of Al coating applied by arc thermal spray process to enhance corrosion resistance performance in artificial ocean water. The porosity is the inherent property of arc thermal spray coating process. In this study, applied coating was treated with different concentrations of ammonium phosphate mono basic (NH4H2PO4: AP) solution thereafter dried at room temperature and kept in humidity chamber for 7d to deposit uniform film. The corrosion resistance of Al coating and treated samples have been evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques with exposure periods in artificial ocean water. Electrochemical techniques, X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) indicated that phosphate ion would have been retarding corrosion of Al coating effectively. The formation of AHP (Ammonium Aluminum Hydrogen Phosphate Hydrate: NH4)3Al5H6(PO4)8.18H2O) on Al coating surface after treatment with AP is nano sized, crystalline and uniformly deposited but after exposure them in artificial ocean water, they form AHPH (Aluminum hydroxide phosphate hydrate Al3(PO4)2(OH)3(H2O)5) that is very protective, adherent, uniform and plate like morphology of corrosion products. The AHPH is sparingly soluble and adherent to surface and imparted improved corrosion resistance. PMID:28157233

  8. An effective and novel pore sealing agent to enhance the corrosion resistance performance of Al coating in artificial ocean water

    Science.gov (United States)

    Lee, Han-Seung; Singh, Jitendra Kumar; Ismail, Mohamed A.

    2017-02-01

    A new technique was accepted to fill the porosity of Al coating applied by arc thermal spray process to enhance corrosion resistance performance in artificial ocean water. The porosity is the inherent property of arc thermal spray coating process. In this study, applied coating was treated with different concentrations of ammonium phosphate mono basic (NH4H2PO4: AP) solution thereafter dried at room temperature and kept in humidity chamber for 7d to deposit uniform film. The corrosion resistance of Al coating and treated samples have been evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques with exposure periods in artificial ocean water. Electrochemical techniques, X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) indicated that phosphate ion would have been retarding corrosion of Al coating effectively. The formation of AHP (Ammonium Aluminum Hydrogen Phosphate Hydrate: NH4)3Al5H6(PO4)8.18H2O) on Al coating surface after treatment with AP is nano sized, crystalline and uniformly deposited but after exposure them in artificial ocean water, they form AHPH (Aluminum hydroxide phosphate hydrate Al3(PO4)2(OH)3(H2O)5) that is very protective, adherent, uniform and plate like morphology of corrosion products. The AHPH is sparingly soluble and adherent to surface and imparted improved corrosion resistance.

  9. Optimized polymer coating for magnesium alloy-based bioresorbable scaffolds for long-lasting drug release and corrosion resistance.

    Science.gov (United States)

    Xu, Wei; Yagoshi, Kai; Koga, Yuki; Sasaki, Makoto; Niidome, Takuro

    2018-03-01

    Magnesium (Mg) alloy-based bioresorbable scaffolds (BRSs) are attracting interest as next-generation stents. However, because medical Mg alloy materials degrade relatively quickly in physiological media, surface corrosion protection via biodegradable polymer coatings is important for clinical applications. Herein, the influence of biodegradable polymer coatings on the BRS corrosion was investigated. First, elution of the drug sirolimus (SRL) from various biodegradable polymers was estimated, including poly(d,l-lactic acid) (PDLLA), poly(d,l-lactic acid-co-ε-caprolactone) (PLCL) and poly(ε-caprolactone) (PCL). Among these, the PDLLA polymer exhibited the slowest release and the best character as a drug reservoir because of its slow degradation rate and semi-glass state in a biological environment. However, the corrosion rate of the PDLLA-coated Mg alloy (AZ31)-based platform was as rapid as the non-coated platform, while critical defects, cracking and desorption were observed in the PDLLA layer. Coatings comprising PCL and PLCL exhibited a prolonged platform corrosion resistance compared with that of PDLLA. To combine the advantages of each polymer, therefore, a pre-coating of PCL or PLCL was applied to the interface between the platform and the external SRL-loaded PDLLA layer. This layering exhibited an enhanced platform corrosion resistance, and will be an important foundational procedure for the development of a coronary scaffold comprising magnesium alloys. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. CORROSION RESISTANT SOL–GEL COATING ON 2024-T3 ALUMINUM

    Directory of Open Access Journals (Sweden)

    S. Yazdani

    2016-06-01

    Full Text Available The inherent reactivity of the Al–Cu alloys is such that their use for structural, marine, and aerospace components and structures would not be possible without prior application of a corrosion resistance system. Historically these corrosion resistance coatings were based on the use of chemicals containing Cr (VI compounds. Silane coatings are of increasing interest in industry due to their potential application for the replacement of current toxic hexavalent chromate based treatments. In this study, hydrophobic coating sol was prepared with methyltriethoxysilane (MTES, methanol (MeOH, and water (as 7M NH4OH at a molar ratio of 1:25:4.31 respectively. The coatings were applied by a dip-technique to 2024-T3 Al alloy, and subsequently cured at room temperature and there after heat treated in an oven at 150°C. The anticorrosion properties of the coatings within 3.5 wt% NaCl solution were studied by Tafel polarization technique. The sol–gel coating exhibited good anticorrosion properties providing an adherent protection film on the Al 2024-T3 substrate. The surface properties were characterized by water contact angle measurement, scanning electron microscopy (SEM, and the composition was studied by Fourier transform infrared spectroscopy (FTIR.

  11. Novel anti-corrosion coatings from rubber-modified polybenzoxazine-based polyaniline composites

    Science.gov (United States)

    Caldona, Eugene B.; de Leon, Al Christopher C.; Pajarito, Bryan B.; Advincula, Rigoberto C.

    2017-11-01

    In this work, the use of rubber-modified polybenzoxazine (PBZ) as the polymer matrix for the polyaniline emeraldine salt (PANI ES) filler was studied and demonstrated for the first time for its potential anti-corrosion application for carbon steel. PBZ was chosen as the main polymer component because of its outstanding properties such as near-zero shrinkage upon polymerization, low surface free energy, good dielectric, thermal, and mechanical properties, and most notably, its low water absorption ability. The concentration of the PANI ES was varied and the anti-corrosion property of varying loadings of PANI ES was tested. Results of the electrochemical measurements afterimmersion in chloride solution showed that the rubber-modified PBZ is able to protect the carbon steel from corrosion attack. On the other hand, the composites with different PANI ES concentrations were observed to be even more effective in protecting the carbon steel against corrosion. But when the immersion time was prolonged and results were compared, it was found that a low concentration of the PANI ES is needed to tune the anti-corrosion property of the coating to its optimum performance.

  12. The use of welding techniques in protection of welding structures against corrosion

    Directory of Open Access Journals (Sweden)

    J.St. Kowalski

    2010-07-01

    Full Text Available The paper presents possibilities of using welding techniques as a means of protection from corrosion of materials for welding structuresoperating in power engineering industry, chemical industry and shipbuilding. Based on the example of an LNG installation, the potentials of weld overlaying in anti-corrosive protection of parts operating in LNG installations have been described. The weld overlaying technique enables building up of protective coatings, which not only protect material from corrosion resulting from the flow of more or less aggressive medium (e.g. water, exhaust gas but also increase the performance life of thus “coated” elements due to the improved abrasion wear resistance of weld overlays. The weld overlaying process is equally well suitable in building of new structures as in the repair of damaged or worn out elements of water or power feeding installations.

  13. Characterization of protective sol-gel coatings on magnesium based on phenyl-triethoxysilane precursor

    Energy Technology Data Exchange (ETDEWEB)

    Yekehtaz, M., E-mail: yekehtaz@ca.tu-darmstadt.d [Technische Universitaet Darmstadt, Department of Materials Science, Petersenstr. 23, 64287 Darmstadt (Germany); Sittner, F.; Ugas-Carrion, R.; Flege, S.; Broetz, J.; Ensinger, W. [Technische Universitaet Darmstadt, Department of Materials Science, Petersenstr. 23, 64287 Darmstadt (Germany)

    2010-07-01

    Sol-gel coatings were deposited from a Phenyl-triethoxysilane precursor for corrosion protection on magnesium samples. Film porosity was measured with potentiodynamic scans and the coating's structure was characterized with secondary ion mass spectrometry and X-ray diffraction analysis. At the interface between substrate and coating a magnesium silicate layer was found which was formed by interdiffusion during the deposition process. The coated samples showed a good corrosion resistance and low porosity after heating at comparatively low temperature.

  14. Review of hot corrosion of thermal barrier coatings of gas turbine

    Directory of Open Access Journals (Sweden)

    LIU Yongbao

    2017-03-01

    Full Text Available The review was done in order to make clear the problem of the hot corrosion of the Thermal Barrier Coatings(TBCsduring gas turbine serving. This paper summarizes the factors resulting from the hot corrosion of TBCs during turbine service and classifies methods for enhancing the corrosive resistance of TBCs. A prospective methodology for improving corrosion resistance is also formulated. The main types of corrosion coating include phase reaction, oxidizing of the bond coating, salt-fog corrosion, CMAS corrosion and fuel impurity corrosion. So far, methods for improving the corrosion resistance of TBCs include developing new coating materials, anticorrosive treatment on the surface of TBCs, modifying the stacking configuration and improving the cleansing functions of the gas turbines. In the future, developing new materials with excellent performance will still be the main direction for boosting the improvement of the hot corrosion resistance of TBCs. Simultaneously, improving the tacking configuration and nanotechnology of TBC coatings are potential approaches for improving corrosion resistance. With the development of a Ceramic Matrix Composite (CMC, the focus of the hot corrosion of TBCs may turn to that of Environmental Barrier Coatings (EBCs.

  15. Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis

    Directory of Open Access Journals (Sweden)

    H. M. Hajar

    2016-01-01

    Full Text Available The corrosion performance of aluminum alloy 5083 (AA5083 was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance (Rct value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value (Cdl is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix.

  16. Adaptive Corrosion Protection System Using Continuous Corrosion Measurement, Parameter Extraction, and Corrective Loop

    Directory of Open Access Journals (Sweden)

    Jasbir N. Patel

    2016-01-01

    Full Text Available A simple current-sourced adaptive corrosion protection system (ACPS along with a technology to extract the protection current from the Tafel plot is presented. For reliable protection of the target metal, first, the Tafel plot of the target metal is obtained. Subsequently, a novel technique proposed in this paper is used to extract the protection current from the Tafel plot. This extracted protection current is fed to the target metal to protect the metal in the existing corrosive environment. This three-part system is adaptively used to update the required protection current to effectively protect the target metal continuously. All these functionalities are integrated in a stand-alone ACPS that effectively diagnoses the corrosion status and updates the protection parameters without any manual interaction or physical modification of the set-up to offer modularity, reliability, and cost saving. To validate the technique, a laboratory scale system is realized and tested using various metal samples and various corrosive mediums. Using the experimental system, A36 metal coupons are effectively protected with protection (inhibition efficiency of 40–100% in different corrosive mediums that can extend the life expectancy of the target metal from ~2 times to more than 100 times for the tested corrosive mediums.

  17. Anti-corrosive performance of electropolymerized phosphomolybdic acid doped PANI coating on 304SS

    Science.gov (United States)

    Gao, Yangzhi; Syed, Junaid Ali; Lu, Hongbin; Meng, Xiangkang

    2016-01-01

    A phosphomolybdic acid doped polyaniline (PANI) anti-corrosive coating was synthesized on stainless steel (304SS) by electropolymerization. The combination of phosphoric acid de-doping and phosphomolybdic acid re-doping processes leads to the direct and quick deposition of PANI-coating on 304SS without any residual oxidant impurities. The corrosion resistance of the coating was evaluated in 1 M H2SO4 solution by electrochemical techniques. The doping of phosphomolybdic acid enhances the corrosion resistance provided by the coating. The phosphomolybdic acid re-doped coating has a high Rt of 1999 Ω cm2 in comparison with the phosphoric acid doped and re-doped coatings. The increase in corrosion resistance is due to the presence of phosphomolybdic acid that promotes the formation of oxides which not only fill the pores in the PANI coating but also forms an interfacial oxide layer and hence block the corrosion of 304SS in acidic medium.

  18. Stainless steel surface biofunctionalization with PMMA-bioglass coatings: compositional, electrochemical corrosion studies and microbiological assay.

    Science.gov (United States)

    Floroian, L; Samoila, C; Badea, M; Munteanu, D; Ristoscu, C; Sima, F; Negut, I; Chifiriuc, M C; Mihailescu, I N

    2015-06-01

    A solution is proposed to surpass the inconvenience caused by the corrosion of stainless steel implants in human body fluids by protection with thin films of bioactive glasses or with composite polymer-bioactive glass nanostructures. Our option was to apply thin film deposition by matrix-assisted pulsed laser evaporation (MAPLE) which, to the difference to other laser or plasma techniques insures the protection of a more delicate material (a polymer in our case) against degradation or irreversible damage. The coatings composition, modification and corrosion resistance were investigated by FTIR and electrochemical techniques, under conditions which simulate their biological interaction with the human body. Mechanical testing demonstrates the adhesion, durability and resistance to fracture of the coatings. The coatings biocompatibility was assessed by in vitro studies and by flow cytometry. Our results support the unrestricted usage of coated stainless steel as a cheap alternative for human implants manufacture. They will be more accessible for lower prices in comparison with the majority present day fabrication of implants using Ti or Ti alloys.

  19. Corrosion Behavior of Detonation Gun Sprayed Fe-Al Type Intermetallic Coating

    Directory of Open Access Journals (Sweden)

    Cezary Senderowski

    2015-03-01

    Full Text Available The detonation gun sprayed Fe-Al type coatings as an alternative for austenitic valve steel, were investigated using two different methods of testing corrosion resistance. High temperature, 10-hour isothermal oxidation experiments at 550, 750, 950 and 1100 °C show differences in the oxidation behavior of Fe-Al type coatings under air atmosphere. The oxide layer ensures satisfying oxidation resistance, even at 950 and 1100 °C. Hematite, α-Al2O3 and metastable alumina phases were noticed on the coatings top surface, which preserves its initial thickness providing protection to the underlying substrate. In general, only negligible changes of the phase composition of the coatings were noticed with simultaneous strengthening controlled in the micro-hardness measurements, even after 10-hours of heating at 1100 °C. On the other hand, the electrochemical corrosion tests, which were carried out in 200 ppm Cl− (NaCl and pH ~4 (H2SO4 solution to simulate the acid-rain environment, reveal higher values of the breakdown potential for D-gun sprayed Fe-Al type coatings than the ones for the bulk Fe-Al type alloy and Cr21Mn9Ni4 austenitic valve steel. This enables these materials to be used in structural and multifunctional applications in aggressive environments, including acidic ones.

  20. Investigation of influence of structure and TiAl3/TiAlN intermetallic coatings on the corrosion behavior of martensitic steels

    Science.gov (United States)

    Vardanyan, E.; Ramazanov, K.; Yagafarov, I.; Khamzina, A.; Agzamov, R.

    2017-05-01

    The paper considers several approaches to protect martensitic steels with ultrafine-grain (UFG) structure in aggressive environments. Scanning electron microscopy was used to study the microstructure and composition of steel substrates and coatings. The samples were also subjected to corrosion tests. Regularities of corrosion behavior were specified for the UFG steels. The samples were subjected to ion nitriding in a glow discharge and deposition of protective TiAl3/TiAlN coatings in vacuum arc discharge plasma. Corrosion rates were identified for different treatments.

  1. Use of coatings for protection of welded joints of steels, their structure and properties

    Science.gov (United States)

    Bezborodov, V. P.; Saraev, Yu N.

    2017-05-01

    The paper studies the structure and demonstrates the efficiency of application of eutectic nickel coatings for protection of welded joints of the 10G2S-type steels from corrosive action. It increases simultaneously with the increase of eutectic content and chemical compounds along the grain boundaries of the γ-solid solution based on nickel. The refinement of the coatings’ structure and the reduction of their heterogeneity allow enhancing the protective properties and resistance of welded joints to corrosion.

  2. Electron beam processed plasticized epoxy coatings for surface protection

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Mervat S. [National Center for Radiation Research and Technology, Nasr City (Egypt); Mohamed, Heba A., E-mail: hebaamohamed@gmail.com [National Research Center, Dokki (Egypt); Kandile, Nadia G. [University College for Girls, Ain Shams University (Egypt); Said, Hossam M.; Mohamed, Issa M. [National Center for Radiation Research and Technology, Nasr City (Egypt)

    2011-10-17

    Highlights: {center_dot} Coating formulations with EA 70%, HD 20%, and castor oil 10% under 1 Mrad pass{sup -1} irradiation dose showed the best adhesion and passed bending tests. {center_dot} The prepared EP-SF-An adduct improve anti-corrosion properties of coatings without any significant effect on physical, mechanical and chemical properties of the cured film. The optimum amount of aniline adduct as corrosion inhibitor was found to be 0.4 g for 100 g of coating formulation. {center_dot} The corrosion inhibition efficiency of the prepared adduct competed the commercial efficiency. - Abstract: Epoxy acrylate oligomer (EA) was plasticized by adding different plasticizers such as epoxidized soybean oil, glycerol and castor oil and cured by electron beam (EB). Different irradiation doses (1, 2.5 and 5 Mrad pass{sup -1}) were used in the curing process. The effect of both different irradiation doses and plasticizers on the end use performance properties of epoxy acrylate coating namely, pencil hardness, bending test, adhesion test, acid and alkali resistance test were studied. It was observed that incorporation of castor oil in epoxy acrylate diluted by 1,6-hexanediol diacrylate (HD) monomer with a ratio (EA 70%, HD 20%, castor oil 10%) under 1 Mrad pass{sup -1} irradiation dose improved the physical, chemical and mechanical properties of cured films than the other plasticizer. Sunflower free fatty acid was epoxidized in situ under well established conditions. The epoxidized sunflower free fatty acids (ESFA) were subjected to react with aniline in sealed ampoules under inert atmosphere at 140 deg. C. The produced adducts were added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was found that, addition of 0.4 g of aniline adduct to 100 g epoxy acrylate formula may give the best corrosion

  3. Corrosion and wear behaviours of a reactive-sputter-deposited Ta2O5 nanoceramic coating

    Science.gov (United States)

    Hu, Wei; Xu, Jiang; Lu, Xiaolin; Hu, Dongsheng; Tao, Hongliang; Munroe, Paul; Xie, Zong-Han

    2016-04-01

    In order to improve the wear and corrosion resistance of Ti-6Al-4V, a novel β-Ta2O5 nanoceramic coating was synthesised using reactive sputter deposition enabled by double glow discharge plasma technique. The surface topography, chemical composition, and microstructure of the newly developed coating were characterised by a variety of surface analytical techniques. The coating microstructure was found to exhibit a compact striated pattern extending in a direction perpendicular to coating surface, which is composed of equiaxed β-Ta2O5 grains with an average grain size of ∼20 nm, well adhered to the Ti-6A1-4V substrate. The hardness and the Young's modulus of the as-deposited coating were obtained by nanoindentation, and the adhesion strength between the coating and substrate was determined by a scratch tester. The dry sliding wear behaviours of the coating were investigated at room temperature against Si3N4 ceramic balls at room temperature under applied loads ranging from 2.3 N to 5.3 N using a ball-on-disc tribometer. The specific wear rates of the coating exhibited only a slight increase with applied normal load, and were shown to be two orders of magnitude lower than that for Ti-6Al-4V under the same loading condition. Furthermore, the electrochemical behaviour of the coating immersed in 3.5 wt.% NaCl solution was systematically examined by using a range of complementary electrochemical techniques including potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis as well as potential of zero charge (PZC). The results showed that the corrosion resistance of the β-Ta2O5 nanoceramic coating was better than that of Ti-6Al-4V alloy in 3.5 wt.% NaCl solution. Hence, by possessing higher mechanical properties and good wear and corrosion resistance, the β-Ta2O5 nanoceramic coating is considered to be a promising candidate for protection of engineering components operating under harsh conditions.

  4. Enhancement of active corrosion protection via combination of inhibitor-loaded nanocontainers.

    Science.gov (United States)

    Tedim, J; Poznyak, S K; Kuznetsova, A; Raps, D; Hack, T; Zheludkevich, M L; Ferreira, M G S

    2010-05-01

    The present work reports the synthesis of layered double hydroxides (LDHs) nanocontainers loaded with different corrosion inhibitors (vanadate, phosphate, and 2-mercaptobenzothiazolate) and the characterization of the resulting pigments by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The anticorrosion activity of these nanocontainers with respect to aluminum alloy AA2024 was investigated by electrochemical impedance spectroscopy (EIS). The bare metallic substrates were immersed in dispersions of nanocontainers in sodium chloride solution and tested to understand the inhibition mechanisms and efficiency. The nanocontainers were also incorporated into commercial coatings used for aeronautical applications to study the active corrosion protection properties in systems of industrial relevance. The results show that an enhancement of the active protection effect can be reached when nanocontainers loaded with different inhibitors are combined in the same protective coating system.

  5. Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure and method of processing

    Science.gov (United States)

    Brown, Jr., Jesse J.; Hirschfeld, Deidre A.; Li, Tingkai

    1993-12-07

    Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

  6. Study of electroless Ni Cu P coatings and their anti-corrosion properties

    Science.gov (United States)

    Liu, Y.; Zhao, Q.

    2004-04-01

    Copper content in electroless Ni-Cu-P alloy coatings mainly depends on pH, temperature and Cu 2+ concentration in plating solution and has a significant effect on the corrosion resistance of the coatings. In this paper, the effects of pH, temperature, Cu 2+ concentrations and substrate materials on the deposition rate and the coating compositions were studied. The coating thickness and their compositions were measured using a digital micrometer and an energy dispersive X-ray microanalysis (EDX), respectively. The anti-corrosion properties of the Ni-Cu-P coatings in HCl and NaCl solutions were investigated. The results showed that the corrosion resistance of the Ni-Cu-P alloy coatings was superior to that of electroless Ni-P coatings or copper. The optimal conditions for preparing these corrosion-resistant Ni-Cu-P coatings were obtained.

  7. Microstructure and corrosion properties of CrMnFeCoNi high entropy alloy coating

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Qingfeng [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Lu, Fenggui [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China); Li, Ruifeng [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, 212003 (China); Huang, Jian; Wu, Yixiong [Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai, 200240 (China)

    2017-02-28

    Highlights: • Equimolar CrMnFeCoNi high entropy alloy coating are prepared by laser cladding. • The cladding layer forms a simple FCC phase solid solution with identical dendritic structure. • The cladding layer exhibits a noble corrosion resistance in both 3.5 wt.% NaCl and 0.5 M sulfuric acid. • Element segregation makes Cr-depleted interdendrites the starting point of corrosion reaction. - Abstract: Equimolar CrMnFeCoNi high entropy alloy (HEA) is one of the most notable single phase multi-component alloys up-to-date with promising mechanical properties at cryogenic temperatures. However, the study on the corrosion behavior of CrMnFeCoNi HEA coating has still been lacking. In this paper, HEA coating with a nominal composition of CrMnFeCoNi is fabricated by laser surface alloying and studied in detail. Microstructure and chemical composition are determined by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used to investigate the corrosion behavior. The coating forms a simple FCC phase with an identical dendritic structure composed of Fe/Co/Ni-rich dendrites and Mn/Ni-rich interdendrites. Both in 3.5 wt.% NaCl solution and 0.5 M sulfuric acid the coating exhibits nobler corrosion resistance than A36 steel substrate and even lower i{sub corr} than 304 stainless steel (304SS). EIS plots coupled with fitted parameters reveal that a spontaneous protective film is formed and developed during immersion in 0.5 M sulfuric acid. The fitted R{sub t} value reaches its maximum at 24 h during a 48 h’ immersion test, indicating the passive film starts to break down after that. EDS analysis conducted on a corroded surface immersed in 0.5 M H{sub 2}SO{sub 4} reveals that corrosion starts from Cr-depleted interdendrites.

  8. Protection of Reinforcement with Corrosion Inhibitors, Phase II

    Science.gov (United States)

    2000-12-01

    Costs due to corrosion of reinforcement in concrete caused by deicing salts have been estimated at up to $1 billion per year in the U.S. alone. For most situations, corrosion-inhibiting admixtures offer significant advantages over other protection me...

  9. Electropolymerisation of Aniline on AZ91 Magnesium Alloy: The Effect of Coating Electrolyte Corrosiveness

    OpenAIRE

    Asif Baloch; M. Bobby Kannan

    2017-01-01

    In this study, polyaniline was coated on AZ91 magnesium alloy using an electropolymerisation technique, and the effect of corrosiveness of the coating electrolytes on the polymerisation and the coating performance were evaluated. Two electrolytes, i.e., aniline + sodium salicylate (PASS) and aniline + potassium hydroxide (PAPH), with different corrosiveness, were used for polyaniline coating on AZ91 magnesium alloy. Potentiodynamic polarisation results suggested that salicylic acid (C7H5NaO3)...

  10. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

    Directory of Open Access Journals (Sweden)

    A. Nikitin

    2017-01-01

    Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

  11. Dense protective coatings, methods for their preparation and coated articles

    Science.gov (United States)

    Tulyani, Sonia; Bhatia, Tania; Smeggil, John G.

    2015-12-29

    A method for depositing a protective coating on a complex shaped substrate includes the steps of: (1) dipping a complex shaped substrate into a slurry to form a base coat thereon, the slurry comprising an aqueous solution, at least one refractory metal oxide, and at least one transient fluid additive present in an amount of about 0.1 percent to 10 percent by weight of the slurry; (2) curing the dipped substrate; (3) dipping the substrate into a precursor solution to form a top barrier coat thereon; and (4) heat treating the dipped, cured substrate to form a protective coating.

  12. TiO{sub 2} coated multi-wall carbon nanotube as a corrosion inhibitor for improving the corrosion resistance of BTESPT coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuping; Zhu, Hongzheng; Zhuang, Chen [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Chen, Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Wang, Longqiang [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Dong, Lihua [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China); Yin, Yansheng, E-mail: ysyin@shmtu.edu.cn [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China)

    2016-08-15

    The composite coatings of TiO{sub 2} coated multi-wall carbon nanotube (MWCNTs)/bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technique and the experimental conditions were optimized to attain the appropriate volume ratio. The modified MWCNTs obviously improved the corrosion resistance of BTESPT and BTESPT/TiO{sub 2} coatings, especially for the long-term corrosion resistance ability because of the good dispersion of MWCNTs. The geometry of composite coatings were explored by scanning electron microscopy, fourier transform infrared spectra and the surface coverage rate (θ), the results indicate that the composite coatings produce good cross-linked structure at the interfacial layer, the coating compactness increases gradually with the addition of TiO{sub 2} and/or MWCNTs, and the composite coating effectively postpones the production of cracks with the addition of MWCNTs. - Highlights: • The composite coatings with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technology. • The formation of composite coating on AA 2024 surface considerably improved the corrosion resistance ability. • The composite coating with a TiO{sub 2} to MWCNTs volume ratio of 4/1 shows the best corrosion resistance. • The kinetic evaluation of inhibitive behavior for different coatings against immersion time was explored.

  13. Improvement on the corrosion protection of conductive polymers in PEMFC environments by adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rodriguez, J.G.; Lucio-Garcia, M.A.; Nicho, M.E.; Cruz-Silva, R. [UAEM-CIICAP, Av. Universidad 1001, Col. Chamilpa, 62209-Cuernavaca, Morelos (Mexico); Casales, M. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencicas Fisicas, Av. Universidad s/n, Col. Chamilpa, 62210-Cuernavaca, Morelos (Mexico); Valenzuela, E. [Universidad Politecnica de Chiapas, Cuerpo Academico de Energia y Sustentabilidad Eduardo J. Selvas S/N, Col. Magisterial, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-05-25

    The corrosion protection of polypyrrol (PPY) and polyaniline (PANI) coatings electrochemically deposited with and without polyvinyl alcohol (PVA) as adhesive onto 304 type stainless steel has been evaluated using electrochemical techniques. Environment included 0.5 M H{sub 2}SO{sub 4} at 60 C whereas employed techniques included potentiodynamic polarization curves (PC), linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements. Results showed that the free corrosion potential, of the substrate, E{sub corr}, was made more noble up to 500 mV with the polymeric coatings. The corrosion rate was lowered by using the polymers, but with the addition of PVA, it was decreased further, one order of magnitude for PPY and up to three orders of magnitude for PANI. Impedance spectra showed that the corrosion mechanism is under a Warburgh-type diffusional process of the electrolyte throughout the coating, and that the uptake of the environment causes the eventual failure of the coating corroding the substrate. (author)

  14. Annealing effect on corrosion resistance of Bi{sub x}Ti{sub y}O{sub z} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, M. J.; Alfonsoa, J. E.; Olaya, J. J. [Universidad Nacional de Colombia, Grupo de Ciencia de Materiales y Superficies, Bogota AA 14490 (Colombia); Pineda Vargas, C. A., E-mail: jealfonsoo@unal.edu.co [iThemba LABS, Materials Research Department, PO Box 722, Somerset West 7129 (South Africa)

    2016-11-01

    Bismuth titanate (Bi-xTi{sub y}O{sub z}) has received widespread attention due to the fact that during recent times it has found important applications in strategic research fields such as optics and optoelectronic, and more recently studies have shown how their physicochemical properties may be harnessed in order to be able to use Bi{sub x}Ti{sub y}O{sub z}, as an anti corrosive coating. In this work bismuth titanate (Bi{sub x}Ti{sub y}O{sub z}) coatings were grown on titanium alloy (Ti6A14V) substrates, using RF magnetron sputtering at room temperature. The main objectives of the work were quantify the evolution of crystallographic phase formation, as a function of the annealing temperature, and establish the chemical composition in order to characterize the behaviour of the bismuth titanate coating as a protective coating of the corrosion. The morphology of the coating was observed via scanning electronic microscopy (Sem); the crystalline structure was characterized by X-ray diffraction (XRD) and the chemical composition was analyzed by Rutherford Backscattering Spectrometry (RBS). The corrosion resistance of the coatings was studied by potentiodynamic polarization (Pp) test (Tafel extrapolation). Sem results showed that the surface roughness of the coatings changed when the temperature of annealing increased. Similar change occurred after Pp tests. The XRD analysis revealed a change in the coatings microstructure as a function of the annealing temperature, since they evolved from a completely amorphous phase to a polycrystalline phase. RBS results indicate that coatings growing at high temperature have a complex chemical composition. Finally, the electrochemical analysis showed that the corrosion resistance of the coating is much better in the amorphous phases of bismuth titanate than in the polycrystalline phases. (Author)

  15. Aluminide protective coatings on high–temperature creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-10-01

    Full Text Available This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, especially at high carburizing potential atmosphere. Coatings were obtained on cast steel type G–XNiCrSi36–18 with the following methods: pack cementation, paste method, cast method and slurry cementation. The phase composition, thickness and morphology of coatings were determined. Coatings capacity of carbon diffusion inhibition and thermal shocks resistance of coatings were determined with different methods. It was found, that all of the coatings reduce carbon diffusion in different degree and all coatings liable to degradation in consequence cracking and oxidation. Coating life time is mainly dependent on morphology, phase composition and service condition (thermal shocks first of all.

  16. Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

    2017-06-01

    In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and

  17. 49 CFR 195.557 - Which pipelines must have coating for external corrosion control?

    Science.gov (United States)

    2010-10-01

    ... corrosion control? 195.557 Section 195.557 Transportation Other Regulations Relating to Transportation...) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Corrosion Control § 195.557 Which pipelines must have coating for external corrosion control? Except bottoms of aboveground breakout tanks, each...

  18. Stepwise Depletion of Coating Elements as a Result of Hot Corrosion of NiCrAlY Coatings

    Science.gov (United States)

    Rana, Nidhi; Jayaganthan, R.; Prakash, Satya

    2013-11-01

    Present investigation deals with the hot corrosion behaviour of the NiCrAlY coatings deposited by HVOF technique on Superni76 under cyclic conditions at 900 °C in the presence of Na2SO4 + 60% V2O5 salt. The weight change behaviour of the coatings was followed with time up to 200 cycles and K p value was calculated for the hot corrosion process. Surface and cross-section of the corroded samples were examined by FESEM/EDS and XRD to follow the progress of corrosion up to 200 cycles. In earlier cycles, the corrosive species oxidised top surface of the coatings. With increasing number of cycles, oxidation of the coatings occurred up to 40-μm depth. A Cr-depleted band was seen below the oxide scale. Further increase in number of cycles led to migration and oxidation of Al to form Al2O3 sublayer at coating/scale interface, thereby leading to formation of Al-depleted zone in the coating below the Al2O3 sublayer. The corrosion resistance of the NiCrAlY coatings is attributed to the formation of the continuous and dense Al2O3 sublayer at the coating/scale interface, which acts as barrier to the migration of Cr to the surface. The appearance of Al3Y after 100 and 200 cycles also contributes to the increased corrosion resistance of coatings after 100 and 200 cycles.

  19. Corrosion Protection for Space and Beyond

    Science.gov (United States)

    Calle, Luz Marina

    2007-01-01

    Florida is home to NASA's Launch Operations Center. Since its establishment in July 1962, the spaceport has served as the departure gate for every American manned mission and hundreds of advanced scientific spacecraft under the Launch Services Program. The center was renamed the John F. Kennedy Space Center in late 1963 to honor the president who put America on the path to the moon. Today, NASA is on the edge of a bold new chaIlenge: the ConsteIlation Program. ConsteIlation is a NASA program to create a new generation of spacecraft for human spaceflight, consisting primarily of the Ares I and Ares V launch vehicles, the Orion crew capsule, the Earth Departure stage and the Lunar access module. These spacecraft will be capable of performing a variety of missions, from Space Station resupply to lunar landings. The ambitious new endeavor caIls for NASA to return human explorers to the moon and then venture even farther, to Mars and beyond. As the nation's premier spaceport, Kennedy Space Center (KSC) will playa critical role in this new chapter in exploration, particularly in the conversion of the launch facilities to accommodate the new launch vehicles. To prepare for this endeavor, the launch site and facilities for the next generation of crew and cargo vehicles must be redesigned, assembled and tested. One critical factor that is being carefuIly considered during the renovation is protecting the new facilities and structures from corrosion and deterioration.

  20. Corrosion behavior of HVOF sprayed hard face coatings in alkaline-sulfide solution

    Science.gov (United States)

    Li, Shenhou; Guo, Zhixing; Xiong, Ji; Lei, Yong; Li, Yuxi; Tang, Jun; Liu, Junbo; Ye, Junliu

    2017-09-01

    The paper focuses on the corrosion behavior of high velocity oxygen fuel (HVOF) sprayed WC-17Co, WC-10Co-4Cr, Cr3C2-25NiCr coatings in alkaline-sulfide solution (S2-, 0.2 ml/L, pH = 10). Eighteen days of immersion test is carried out and corrosion rate analysis shows that the Cr3C2-NiCr coating of low porosity exhibits the best corrosion resistance. In alkaline-sulfide solutions, porosity, passive film and microgalvanic between hard phase and binder phase have significant effect on the corrosion behavior of coatings. The corrosion mainly occurs in binder phase from SEM, though WO3, WS2, Cr2S3 are detected in XPS. In WC-17Co coating, the binder phase Co transforms to Co oxides and serious corrosion can be observed in binder phase. WC-10Co-4Cr coatings suffer localized corrosion since galvanic corrosion occurs between locations with different solubilities of W in Co binder. Cr3C2-25NiCr coating shows slight corrosion with the formation of NiS/Ni2O3/Cr2O3from the binder and Cr2S3 from the hard phase. The results are verified by the polarization curves, which show the longest passive region and lowest Icorrosion of Cr3C2-25NiCr coating.

  1. Investigation of the Corrosion Behavior of Electroless Ni-P Coating in Flue Gas Condensate

    Directory of Open Access Journals (Sweden)

    Hejie Yang

    2017-01-01

    Full Text Available The corrosion behavior of Ni-P coating deposited on 3003 aluminum alloy in flue gas condensate was investigated by electrochemical approaches. The results indicated that nitrite acted as a corrosion inhibitor. The inhibiting effect of nitrite was reduced in solutions containing sulfate or nitrate. Chloride and sulfate accelerated the corrosion of Ni-P coatings greatly. This can provide important information for the researchers to develop special Ni-P coatings with high corrosion resistance in the flue gas condensate.

  2. Electrodeposited Reduced Graphene Oxide Films on Stainless Steel, Copper, and Aluminum for Corrosion Protection Enhancement

    Directory of Open Access Journals (Sweden)

    Abdulkareem Mohammed Ali Al-Sammarraie

    2017-01-01

    Full Text Available The enhancement of corrosion protection of metals and alloys by coating with simple, low cost, and highly adhered layer is still a main goal of many workers. In this research graphite flakes converted into graphene oxide using modified Hammers method and then reduced graphene oxide was electrodeposited on stainless steel 316, copper, and aluminum for corrosion protection application in seawater at four temperatures, namely, 20, 30, 40, and 50°C. All corrosion measurements, kinetics, and thermodynamics parameters were established from Tafel plots using three-electrode potentiostat. The deposited films were examined by FTIR, Raman, XRD, SEM, and AFM techniques; they revealed high percentages of conversion to the few layers of graphene with confirmed defects.

  3. Influence of coating defects on the corrosion behavior of cold sprayed refractory metals

    Science.gov (United States)

    Kumar, S.; Rao, A. Arjuna

    2017-02-01

    The defects in the cold sprayed coatings are critical in the case of corrosion performances of the coatings in aggressive conditions. To understand the influence of coating defects on corrosion, immersion tests have been carried out in HF solution for the cold sprayed and heat treated Titanium, Tantalum and Niobium coatings. Long duration immersion tests reveal inhomogeneous weight losses of the samples prepared at different heat treatment conditions. The weight loss for different coatings has been well corroborated with the coating defects and microstructures. Chemical and micro structural analysis elucidates the reason behind the inhomogeneous performance of different type of cold sprayed coatings in corrosion medium. In the case of cold sprayed titanium, formation of stable oxide along the inter-splat boundary hinders the aggressive attack of the corrosion medium which is not so in other cases.

  4. Green Inhibitors for Corrosion Protection of Metals and Alloys: An Overview

    Directory of Open Access Journals (Sweden)

    B. E. Amitha Rani

    2012-01-01

    Full Text Available Corrosion control of metals is of technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options of protecting metals and alloys against corrosion. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds. As in addition to being environmentally friendly and ecologically acceptable, plant products are inexpensive, readily available and renewable. Investigations of corrosion inhibiting abilities of tannins, alkaloids, organic,amino acids, and organic dyes of plant origin are of interest. In recent years, sol-gel coatings doped with inhibitors show real promise. Although substantial research has been devoted to corrosion inhibition by plant extracts, reports on the detailed mechanisms of the adsorption process and identification of the active ingredient are still scarce. Development of computational modeling backed by wet experimental results would help to fill this void and help understand the mechanism of inhibitor action, their adsorption patterns, the inhibitor-metal surface interface and aid the development of designer inhibitors with an understanding of the time required for the release of self-healing inhibitors. The present paper consciously restricts itself mainly to plant materials as green corrosion inhibitors.

  5. Corrosion behaviour of Ni–Co alloy coatings at Kish Island (marine ...

    Indian Academy of Sciences (India)

    Administrator

    Atmospheric corrosion; nickel–cobalt coating; polarization curve. 1. Introduction. The aim of this study is to investigate the corrosion behaviour of Ni–Co electrodeposition in marine envi- ronment by three methods consisting of atmospheric, salt spray and polarization tests. Nickel alloy coatings are achieved by electroplating ...

  6. Effect of menthol coated craft paper on corrosion of copper in HCl ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 33; Issue 3. Effect of menthol coated craft paper on corrosion of copper in HCl environment. P Premkumar ... Natural menthol was coated on craft paper by impregnation and studied as volatile corrosion inhibitor for copper in hydrochloric acid environment. The effect of ...

  7. Corrosion behaviour of Ni–Co alloy coatings at Kish Island (marine ...

    Indian Academy of Sciences (India)

    In this study, the corrosion behaviour of Ni-Co alloys with low Co content, electroplated on steel substrate in sulphate bath, was investigated. The morphology of coatings was studied by optical and SEM microscopy. The corrosion products were analyzed using EDX. The results showed that Ni–1% Co coatings had a better ...

  8. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions

    Directory of Open Access Journals (Sweden)

    Carolina Parra

    2017-12-01

    Full Text Available In this work we present a study on the performance of CVD (chemical vapor deposition graphene coatings grown and transferred on Ni as protection barriers under two scenarios that lead to unwanted metal ion release, microbial corrosion and allergy test conditions. These phenomena have a strong impact in different fields considering nickel (or its alloys is one of the most widely used metals in industrial and consumer products. Microbial corrosion costs represent fractions of national gross product in different developed countries, whereas Ni allergy is one of the most prevalent allergic conditions in the western world, affecting around 10% of the population. We found that grown graphene coatings act as a protective membrane in biological environments that decreases microbial corrosion of Ni and reduces release of Ni2+ ions (source of Ni allergic contact hypersensitivity when in contact with sweat. This performance seems not to be connected to the strong orbital hybridization that Ni and graphene interface present, indicating electron transfer might not be playing a main role in the robust response of this nanostructured system. The observed protection from biological environment can be understood in terms of graphene impermeability to transfer Ni2+ ions, which is enhanced for few layers of graphene grown on Ni. We expect our work will provide a new route for application of graphene as a protection coating for metals in biological environments, where current strategies have shown short-term efficiency and have raised health concerns.

  9. REACH Compliant Hexavalent Chrome Replacement for Corrosion Protection (HITEA)

    Science.gov (United States)

    2014-11-01

    Trusted to deliver excellence REACH Compliant Hexavalent Chrome Replacement for Corrosion Protection (HITEA) Brad Wiley Rolls-Royce plc The...00-00-2014 4. TITLE AND SUBTITLE REACH Compliant Hexavalent Chrome Replacement for Corrosion Protection (HITEA) 5a. CONTRACT NUMBER 5b. GRANT...and Restriction of Chemicals – legislation. • Hexavalent chrome compounds are classified as substances of very high concern (SVHC) because they are

  10. POLYTETRAFLUOROETHYLENE-RICH POLYPHENLENESULFIDE BLEND TOP COATINGS FOR MITIGATING CORROSION OF CARBON STEEL IN 300 DEGREE CELCIUS BRINE.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA, T.; JUNG, D.

    2006-06-01

    We evaluated usefulness of a coating system consisting of an underlying polyphenylenesulfide (PPS) layer and top polytetrafluoroethylene (PTFE)-blended PPS layer as low friction, water repellent, anti-corrosion barrier film for carbon steel steam separators in geothermal power plants. The experiments were designed to obtain information on kinetic coefficient of friction, surface free energy, hydrothermal oxidation, alteration of molecular structure, thermal stability, and corrosion protection of the coating after immersing the coated carbon steel coupons for up to 35 days in CO{sub 2}-laden brine at 300 C. The superficial layer of the assembled coating was occupied by PTFE self-segregated from PPS during the melt-flowing process of this blend polymer; it conferred an outstanding slipperiness and water repellent properties because of its low friction and surface free energy. However, PTFE underwent hydrothermal oxidation in hot brine, transforming its molecular structure into an alkylated polyfluorocarboxylate salt complex linked to Na. Although such molecular transformation increased the friction and surface free energy, and also impaired the thermal stability of PTFE, the top PTFE-rich PPS layer significantly contributed to preventing the permeation of moisture and corrosive electrolytes through the coating film, so mitigating the corrosion of carbon steel.

  11. Corrosion and protection in reinforced concrete : Pulse cathodic protection: an improved cost-effective alternative

    NARCIS (Netherlands)

    Koleva, D.A.

    2007-01-01

    Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved cost-effective alternative. The aim of the research project was to study the possibilities for establishing a new or improved electrochemical method for corrosion prevention/protection for reinforced concrete.

  12. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    Science.gov (United States)

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Polyoxometalate ionic liquids as self-repairing acid-resistant corrosion protection.

    Science.gov (United States)

    Herrmann, Sven; Kostrzewa, Monika; Wierschem, Andreas; Streb, Carsten

    2014-12-01

    Corrosion is a global problem for any metallic structure or material. Herein we show how metals can easily be protected against acid corrosion using hydrophobic polyoxometalate-based ionic liquids (POM-ILs). Copper metal disks were coated with room-temperature POM-ILs composed of transition-metal functionalized Keggin anions [SiW11 O39 TM(H2 O)](n-) (TM=Cu(II) , Fe(III) ) and quaternary alkylammonium cations (Cn H2 n+1 )4 N(+) (n=7-8). The corrosion resistance against acetic acid vapors and simulated "acid rain" was significantly improved compared with commercial ionic liquids or solid polyoxometalate coatings. Mechanical damage to the POM-IL coating is self-repaired in less than one minute with full retention of the acid protection properties. The coating can easily be removed and recovered by rinsing with organic solvents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Waterborne chitosan-epoxysilane hybrid pretreatments for corrosion protection of zinc.

    Science.gov (United States)

    Fernández-Solis, Christian; Erbe, Andreas

    2016-06-23

    Biopolymer-based systems are extensively studied as green alternatives for traditional polymer coatings, e.g., in corrosion protection. Chitosan-epoxysilane hybrid films are presented in this work as a chitosan-based protective system, which could, e.g., be applied in a pretreatment step. For the preparation of the chitosan-epoxysilane hybrid systems, a sol-gel procedure was applied. The function of the silane is to ensure adhesion to the substrate. On zinc substrates, homogeneous thin films with thickness of 50-70 nm were obtained after thermal curing. The hybrid-coated zinc substrates were characterized by infrared spectroscopy, ellipsometry, and x-ray photoelectron spectroscopy. As model corrosion experiments, linear polarization resistance was measured, and cathodic delamination of the weak polymer coating poly(vinylbutyral) (PVB) was studied using scanning Kelvin probe. Overall, chitosan-epoxysilane hybrid pretreated samples showed lower delamination rates than unmodified chitosan coatings and pure PVB. Electrochemical impedance spectroscopy confirmed a reduced ion permeability and water uptake by chitosan-epoxysilane films compared to that of a nonmodified chitosan coating. Even though the coatings are hydrophobic and contain water, they slow down cathodic delamination by limiting ion transport.

  15. Silica doped with lanthanum sol-gel thin films for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Abuin, M. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Serrano, A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); Llopis, J. [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain); Garcia, M.A. [Glass and Ceramic Institute, CSIC, C. Kelsen 5, 28049 Madrid (Spain); IMDEA Nanoscience, Fco. Tomas y Valiente 7, 28049 Madrid (Spain); Carmona, N., E-mail: n.carmona@fis.ucm.es [Department of Materials Physics, Complutense University at Madrid, Avda. Complutense sn, 28004 Madrid (Spain)

    2012-06-01

    We present here anticorrosive silica coatings doped with lanthanum ions for the protection of metallic surfaces as an alternative to chromate (VI)-based conversion coatings. The coatings were synthesized by the sol-gel method starting from silicon alkoxides and two different lanthanum precursors: La (III) acetate hydrate and La (III) isopropoxide. Artificial corrosion tests in acid and alkaline media showed their effectiveness for the corrosion protection of AA2024 aluminum alloy sheets for coating prepared with both precursors. The X-ray absorption Near Edge Structure and X-ray Absorption Fine Structure analysis of the coatings confirmed the key role of lanthanum in the structural properties of the coating determining its anticorrosive properties. - Highlights: Black-Right-Pointing-Pointer Silica sol-gel films doped with lanthanum ions were synthesized. Black-Right-Pointing-Pointer Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. Black-Right-Pointing-Pointer La-acetate is an affordable chemical reactive preferred for the industry. Black-Right-Pointing-Pointer Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. Black-Right-Pointing-Pointer An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

  16. Mitigation of corrosion attack on carbon steel coated cermet alloy in different anion contents

    Science.gov (United States)

    Khalid, Muhamad Azrin Mohd; Ismail, Azzura

    2017-12-01

    This research study evaluated the corrosion mechanism attack on carbon steel coated with cermet alloys (WC-9% Ni) in seawater at different sulphate-to-chloride ratios. The four different sulphate-to-chloride ratios were synthesised with the same seawater salinity of 3.5 % and same pH of real seawater. The corrosion tests involved immersion and electrochemical tests. The immersion test is used to determine the cermet coating ability to withstand the corrosion attack based on different ratios of anions present in the seawater at different periods of immersion. The corrosion attack was characterized by optical and Scanning Electron Microscopy (SEM). The aggressive anions present in the seawater influenced the corrosion attack on the cermet coating. For immersion test, results revealed that increasing sulphate more than chloride, increased the weight loss of cermets. The electrochemistry analysis showed that the passive layer forms on cermet coating prevented the material from further corrosion attack. However, due to its porosity, the passive layer collapsed and exposed the material for other corrosion reaction. For electrochemical test, the result shows that the solution with sulphate-to-chloride ratio of 0.14 (real seawater) has the highest corrosion current and Open Circuit Potential (OCP) compared to other solutions (different sulphate-to-chloride ratio). In conclusion, sulfate and chloride show their competition to attack the cermet coating on carbon steel and the higher the amount of chloride present in seawater, the higher the corrosion rate and pits formed on the cermet coating.

  17. Corrosion Protection of Steel and Bond Durability at Polyphenylene Sulfide-to-Anhydrous Zinc Phosphate Interfaces

    Science.gov (United States)

    1992-01-01

    Corrosion Protection of Steel and Bond Durability at Polyphenylene Sulfide-to-Anhydrous Zinc Phosphate Interfaces 12 PERSONAL AUTHOR(S) T. Sugana. and...anhydrous zinc phosphate I Zn -Ph )conversion coatings containing poly (acid) inhvdride as an inter- facial tailoring material. The factors contributing to...Sulfide-to-Anhydrous Zinc Phosphate Interfaces T. SUGAMA* and N. R. CARCIELLO Energy Efficiency and Conservation Division, Department of Applied Science

  18. Effect of pulse energy and density on laser peening of Inconel 600 without a protective coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joung Soo; Choi, Jong Wan; Chung, Chinman [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Han, Weon JIn; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of)

    2014-05-15

    In this study, a laser peening process without protective coating on an Inconel 600 plate is being developed for application to a BMI (bottom mounted instrument) J-weld and nozzle inner wall in a PWR reactor vessel to prevent PWSCC occurring in weld areas during operating nuclear power plants. To obtain the optimum peening conditions, laser peening was performed in water at different peening parameters to obtain the maximum compressive residual stress and depth on the Alloy 600 plate. From a study on laser peening without a protective surface coating, the effect of its process has been proved to be high enough to prevent Inconel 600 material for stress corrosion cracking. The effect of laser peening on susceptibility to stress corrosion cracking of Inconel 600 was confirmed by stress corrosion cracking tests; no stress corrosion cracking was occurred in a laser-peened specimen, while an un-peened specimen failed by cracking in a very short period of testing time.

  19. Effect of Post-spray Shot Peening Treatment on the Corrosion Behavior of NiCr-Mo Coating by Plasma Spraying of the Shell-Core-Structured Powders

    Science.gov (United States)

    Tian, Jia-Jia; Wei, Ying-Kang; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

    2018-01-01

    Corrosion of metal plays a detrimental role in service lifetime of parts or systems. Therefore, coating a protective film which is fully dense and defects free on the base metal is an effective approach to protect the base metal from corrosion. In this study, a dense NiCr-20Mo coating with excellent lamellar interface bonding was deposited by plasma spraying of the novel shell-core-structured Mo-clad-NiCr powders, and then post-spray shot peening treatment by cold spraying of steel shots was applied to the plasma-sprayed NiCr-20Mo coating to obtain a fully dense coating through eliminating possibly existed pores and un-bonded interfaces within the NiCr-20Mo coating. Corrosion behaviors of the NiCr-20Mo coatings before and after shot peening were tested to investigate the effect of the post-spray shot peening on the corrosion behavior of the NiCr-20Mo coating. Results showed that a much dense and uniform plasma-sprayed NiCr-20Mo coating with perfect lamellar bonding at most of interfaces was deposited. However, the electrochemical tests revealed the existence of through-thickness pores in the as-plasma-sprayed NiCr-20Mo coating. Through the post-spray shot peening treatment, a completely dense top layer in the coating was formed, and with the increase in the shot peening intensity from one pass to three passes, the dense top layer became thicker from 100 μm to reach 300 μm of the whole coating thickness. Thus, a fully dense bulk-like coating was obtained. Corrosion test results showed that the dense coating layer resulting from densification of shot peening can act as an effective barrier coating to prevent the penetration of the corrosive medium and consequently protect the substrate from corrosion effectively. Therefore, a fully dense bulk-like NiCr-20Mo coating with excellent corrosion resistance can be achieved through the plasma spraying of Mo-clad-NiCr powders followed by appropriate post-spray shot peening treatment.

  20. Effect of Post-spray Shot Peening Treatment on the Corrosion Behavior of NiCr-Mo Coating by Plasma Spraying of the Shell-Core-Structured Powders

    Science.gov (United States)

    Tian, Jia-Jia; Wei, Ying-Kang; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

    2017-11-01

    Corrosion of metal plays a detrimental role in service lifetime of parts or systems. Therefore, coating a protective film which is fully dense and defects free on the base metal is an effective approach to protect the base metal from corrosion. In this study, a dense NiCr-20Mo coating with excellent lamellar interface bonding was deposited by plasma spraying of the novel shell-core-structured Mo-clad-NiCr powders, and then post-spray shot peening treatment by cold spraying of steel shots was applied to the plasma-sprayed NiCr-20Mo coating to obtain a fully dense coating through eliminating possibly existed pores and un-bonded interfaces within the NiCr-20Mo coating. Corrosion behaviors of the NiCr-20Mo coatings before and after shot peening were tested to investigate the effect of the post-spray shot peening on the corrosion behavior of the NiCr-20Mo coating. Results showed that a much dense and uniform plasma-sprayed NiCr-20Mo coating with perfect lamellar bonding at most of interfaces was deposited. However, the electrochemical tests revealed the existence of through-thickness pores in the as-plasma-sprayed NiCr-20Mo coating. Through the post-spray shot peening treatment, a completely dense top layer in the coating was formed, and with the increase in the shot peening intensity from one pass to three passes, the dense top layer became thicker from 100 μm to reach 300 μm of the whole coating thickness. Thus, a fully dense bulk-like coating was obtained. Corrosion test results showed that the dense coating layer resulting from densification of shot peening can act as an effective barrier coating to prevent the penetration of the corrosive medium and consequently protect the substrate from corrosion effectively. Therefore, a fully dense bulk-like NiCr-20Mo coating with excellent corrosion resistance can be achieved through the plasma spraying of Mo-clad-NiCr powders followed by appropriate post-spray shot peening treatment.

  1. Development of Protective Coatings for Co-Sequestration Processes and Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Bierwagen, Gordon; Huang, Yaping

    2011-11-30

    The program, entitled Development of Protective Coatings for Co-Sequestration Processes and Pipelines, examined the sensitivity of existing coating systems to supercritical carbon dioxide (SCCO2) exposure and developed new coating system to protect pipelines from their corrosion under SCCO2 exposure. A literature review was also conducted regarding pipeline corrosion sensors to monitor pipes used in handling co-sequestration fluids. Research was to ensure safety and reliability for a pipeline involving transport of SCCO2 from the power plant to the sequestration site to mitigate the greenhouse gas effect. Results showed that one commercial coating and one designed formulation can both be supplied as potential candidates for internal pipeline coating to transport SCCO2.

  2. Evaluation of Corrosion Behavior of Galvanized Steel Treated with Conventional Conversion Coatings and a Chromate-Free Organic Inhibitor

    Directory of Open Access Journals (Sweden)

    Laura A. Hernandez-Alvarado

    2012-01-01

    Full Text Available Conventional weight loss tests and both DC and AC electrochemical techniques were used to study if an organic inhibitor containing an alkanolamine salt of a polycarboxylic acid can substitute toxic coatings as chromating and certain phosphating procedures in the protection of galvanized steel. The electrolyte used was a 0.5 M aerated NaCl solution. All tests gave concordant results, indicating that the chromate-free organic inhibitor does protect galvanized steel in this environment, even though the provided protection was less than that of the chromate conversion coating. It was observed that, after a moderate initial attack, the corrosion rate diminishes due to the appearance and growth of passivating corrosion products layers, mainly constituted by zinc hydroxychloride (Zn5(OH8CI2⋅H2O and two varieties of zinc hydroxide, among other crystalline compounds.

  3. [Effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys].

    Science.gov (United States)

    Li, Lei; Zhu, Zhi-Min; Liao, Yun-Mao

    2009-02-01

    To investigate the effects of Sol-Gel coating on the corrosion resistance of nickel-chronium alloys in vitro. The bond strength of coating-substrate interface sintered at different temperatures (300, 400, 500, 600 degrees C) was tested by scratching method. The Sol-Gel coating was analyzed by scanning electron microscope (SEM), and its corrosion resistance was assessed by a static immersion method. The bond strength of coating-substrate interface reaches the peak at 400 degrees C. The Sol -Gel coating can apparently inhibit the release of metal ions and improve the corrosion resistance of nickel-chromium alloy. Sol-Gel coating can evidently improve corrosion resistance of the nickel-chromium alloy, which has great potential in prospective clinical practice.

  4. Protective film formation on AA2024-T3 aluminum alloy by leaching of lithium carbonate from an organic coating

    NARCIS (Netherlands)

    Liu, Y.; Visser, P.; Zhou, X.; Lyon, S.B.; Hashimoto, T.; Curioni, M.; Gholinia, A.; Thompson, G.E.; Smyth, G.; Gibbon, S.R.; Graham, D.; Mol, J.M.C.; Terryn, H.A.

    2015-01-01

    An investigation into corrosion inhibition properties of a primer coating containing lithium carbonate as corrosion inhibitive pigment for AA2024 aluminum alloy was conducted. It was found that, during neutral salt spray exposure, a protective film of about 0.2 to 1.5 ?m thickness formed within the

  5. Development of Zn-SiC composite coatings: Electrochemical corrosion studies

    Directory of Open Access Journals (Sweden)

    Mudigere Krishnegowda Punith Kumar

    2015-03-01

    Full Text Available The Zn-SiC composite coatings were fabricated by using sulphate plating bath dispersed with 1, 2 and 3 g L-1 of 64.28 nm SiC nanoparticles. Appreciable influence on morphology and microstructure was observed in scanning electron microscopy, X-ray diffraction spectroscopy and texture co-efficient calculations for SiC incorporated zinc coatings. The electrochemical corrosion behavior of zinc and Zn-SiC composite coatings was studied by potentiodynamic polarization and electrochemical impedance analysis. Significant reduction in corrosion current and corrosion rate with increased charge transfer resistance was noticed for composite coatings. The SiC incorporated zinc coatings shown improved micro-hardness property to pure zinc coating. The properties of Zn-SiC composite coatings were compared with that of pure zinc coating.

  6. Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

    Directory of Open Access Journals (Sweden)

    H. Alhumade

    2016-12-01

    Full Text Available Epoxy-Graphene (E/G nanocomposites with different loading of graphene were prepared via in situ prepolymerization and evaluated as protective coating for Stainless Steel 304 (SS304. The prepolymer composites were spin coated on SS304 substrates and thermally cured. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM were utilized to examine the dispersion of graphene in the epoxy matrix. Epoxy and E/G nanocomposites were characterized using X-ray diffraction (XRD and Fourier Transform Infrared (FTIR techniques and the thermal behavior of the prepared coatings is analyzed using Thermogravimetric analysis (TGA and Differential scanning calorimetry (DSC. The corrosion protection properties of the prepared coatings were evaluated using Electrochemical Impedance Spectroscopy (EIS and Cyclic Voltammetry (CV measurements. In addition to corrosion mitigation properties, the long-term adhesion performance of the coatings was evaluated by measuring the adhesion of the coatings to the SS304 substrate after 60 days of exposure to 3.5 wt% NaCl medium. The effects of graphene loading on the impact resistance, flexibility, and UV stability of the coating are analyzed and discussed. SEM was utilized to evaluate post adhesion and UV stability results. The results indicate that very low graphene loading up to 0.5 wt % significantly enhances the corrosion protection, UV stability, and impact resistance of epoxy coatings.

  7. Synthesis and corrosion protection properties of poly(o-phenylenediamine nanofibers

    Directory of Open Access Journals (Sweden)

    P. Muthirulan

    2013-07-01

    Full Text Available The present study shows a novel method for the synthesis of uniformly-shaped poly(othophenylediamine (PoPD nanofibers by chemical oxidative polymerization method for application towards smart corrosion resistance coatings. Transmission Electron Microscopy (TEM and Scanning Electron Microscopy (SEM studies confirm morphology of PoPD with three dimensional (3D networked dendritic superstructures having average diameter of 50–70 nm and several hundred meters of length. UV–vis and FTIR spectral results shows the formation of PoPD nanofibers containing phenazine ring ladder-structure with benzenoid and quinoid imine units. Thermogravimetric analyses (TGA of PoPD nanofibers possess good thermal stability. The anti-corrosion behavior of PoPD nanofibers on 316L SS was investigated in 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS measurements. The PoPD coated 316L SS exhibits higher corrosion potential when compared to uncoated specimen. EIS studies, clearly ascertain that PoPD nanofiber coatings exhibits excellent potential barrier to protect the 316L SS against corrosion in 3.5% NaCl.

  8. Corrosion surface protection by using titanium carbon nitride/titanium-niobium carbon nitride multilayered system

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Cabrera, G. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Aperador, W. [Universidad Militar Nueva Granada Bogota D.C (Colombia); Gomez, M.E. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Calle 13 100-00 Edificio 320, espacio 1026, Cali (Colombia)

    2011-07-29

    The aim of this work is the improvement of the electrochemical behavior of 4140 steel substrate using TiCN/TiNbCN multilayered system as a protective coating. We have grown [TiCN/TiNbCN]{sub n} multilayered via reactive r.f. magnetron sputtering technique in which was varied systematically the bilayer period ({Lambda}), and the bilayer number (n), maintaining constant the total thickness of the coatings ({approx} 3 {mu}m). The coatings were characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy and transmission electron microscopy assisted with selected area electron diffraction. The electrochemical properties were studied by Electrochemical Impedance Spectroscopy and Tafel curves. XRD results showed a preferential growth in the face-centered cubic (111) crystal structure for [TiCN/TiNbCN]{sub n} multilayered coatings [1]. In this work was obtained the maximum corrosion resistance for the coating with ({Lambda}) equal to 15 nm, corresponding to n = 200 bilayered. The polarization resistance and corrosion rate were around 8.6 kOhm cm{sup 2} and 7.59 . 10{sup -4} mm/year, these values were 8.6 and 0.001 times better than those showed by the uncoated 4140 steel substrate (1.0 kOhm and 0.57 mm/year), respectively. The improvement of the electrochemical behavior of the 4140 coated with this TiCN/TiNbCN multilayered system can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl{sup -} ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.

  9. Anti-corrosive and anti-microbial properties of nanocrystalline Ni-Ag coatings

    Energy Technology Data Exchange (ETDEWEB)

    Raghupathy, Y.; Natarajan, K.A.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in

    2016-04-15

    Graphical abstract: - Highlights: • Electrodeposition yielded phase-segregated, nanocrystalline Ni-Ag coatings. • Ni-Ag alloys exhibited smaller Ni crystals compared to pure Ni. • Ultra fine Ni grains of size 12–14 nm favoured Ni-Ag solid solution. • Nanocrystalline Ag resisted bio-fouling by Sulphate Reducing bacteria. • Ni-Ag outperformed pure Ni in corrosion and bio-corrosion tests. - Abstract: Anti-corrosive and anti-bacterial properties of electrodeposited nanocrystalline Ni-Ag coatings are illustrated. Pure Ni, Ni-7 at.% Ag, & Ni-14 at.% Ag coatings were electrodeposited on Cu substrate. Coating consisted of Ni-rich and Ag-rich solid solution phases. With increase in the Ag content, the corrosion resistance of the Ni-Ag coating initially increased and then decreased. The initial increase was due to the Ni-Ag solid solution. The subsequent decrease was due to the increased galvanic coupling between the Ag-rich and Ni-rich phases. For all Ag contents, the corrosion resistance of the Ni-Ag coating was higher than the pure Ni coating. Exposure to Sulphate Reducing Bacteria (SRB) revealed that the extent of bio-fouling decreased with increase in the Ag content. After 2 month exposure to SRB, the Ni-Ag coatings demonstrated less loss in corrosion resistance (58% for Ni-7 at.% Ag and 20% for Ni-14 at.% Ag) when compared pure Ni coating (115%).

  10. Corrosion-resistant coating for GTE compressor parts made of steels with low tempering temperatures

    Science.gov (United States)

    Muboyadzhyan, S. A.; Egorova, L. P.; Gorlov, D. S.; Bulavintseva, E. E.

    2017-01-01

    The corrosion resistance of an Ni-Co-Cr-Al-Si-Y + SPh (SPh is silicophosphate impregnation) alloy coating on 30Kh13, 38Kh2MYuA, VKS5, and VKS7 structural steels with low tempering temperatures has been studied. The steel-coating compositions have been tested to determine the accelerated cyclic corrosion resistance, the corrosion resistance under tropic climate chamber conditions and in salt fog, the stress corrosion resistance, and the corrosion resistance in an industrial atmosphere. The heat stability of coated samples is studied, metallographic studies of the samples before and after the tests are performed, and the influence of the coating on the strength characteristics of the structural steels is studied.

  11. An investigation on corrosion protection layers in pipelines transporting hydrocarbons

    Directory of Open Access Journals (Sweden)

    Giovanna Gabetta

    2014-10-01

    Full Text Available Chemical reactions between carbon steel, water and chemical species produce corrosion layers (scales on the internal surface of pipelines transporting hydrocarbons. Scales act as a diffusion barrier and prevent the progress of corrosion, a dangerous failure initiator. The protective film (10-100 μm thickness can be removed locally by the action of the internal flow, or by other mechanisms. Adhesion with the substrate and the failure modes of the corrosion layer can be tested by indentation. Some results are presented of experiments performed on specimens with scales grown in a controlled environment.

  12. Effect of Native Oxide Film on Commercial Magnesium Alloys Substrates and Carbonate Conversion Coating Growth and Corrosion Resistance

    Science.gov (United States)

    Feliu, Sebastián; Samaniego, Alejandro; Bermudez, Elkin Alejandro; El-Hadad, Amir Abdelsami; Llorente, Irene; Galván, Juan Carlos

    2014-01-01

    Possible relations between the native oxide film formed spontaneously on the AZ31 and AZ61 magnesium alloy substrates with different surface finish, the chemistry of the outer surface of the conversion coatings that grows after their subsequent immersion on saturated aqueous NaHCO3 solution treatment and the enhancement of corrosion resistance have been studied. The significant increase in the amount of aluminum and carbonate compounds on the surface of the conversion coating formed on the AZ61 substrate in polished condition seems to improve the corrosion resistance in low chloride ion concentration solutions. In contrast, the conversion coatings formed on the AZ31 substrates in polished condition has little effect on their protective properties compared to the respective as-received surface. PMID:28788582

  13. Enhancement of corrosion protection effect in mechanochemically synthesized Polyaniline/MMT clay nanocomposites

    Directory of Open Access Journals (Sweden)

    N. Kalaivasan

    2017-02-01

    Full Text Available Nanocomposite material that consists of DBSA (dodecylbenzensulfonic acid doped polyaniline (PANI was prepared by solvent free mechanochemical intercalation method. Organic aniline monomer was first intercalated into the interlayer regions of Na-MMT (sodium montmorillonite clay hosts and followed by one-step oxidative polymerization. The as synthesized polyaniline clay nanocomposites were treated with DBSA to get PANI-DBSA clay nanocomposites. PANI-DBSA clay nanocomposites in the form of coatings at different concentrations of DBSA on C45 steel were found much superior in corrosion protection over those of conventional polyaniline, based on the series of electrochemical measurement of corrosion potential, polarization resistance and corrosion current in 3.5% aqueous NaCl electrolyte. UV–visible spectroscopy, FT-IR and SEM studies confirm the formation of intercalated polyaniline clay nanocomposites inside the clay nanolayers.

  14. Synthesis of Silica/Polypyrrole Nanocomposites and Application in Corrosion Protection of Carbon Steel.

    Science.gov (United States)

    Van, Vu Thi Hai; Hang, To Thi Xuan; Nam, Pham Thi; Phuong, Nguyen Thu; Thom, Nguyen Thi; Devilliers, Didier; Thanh, Dinh Thi Mai

    2018-06-01

    Silica/polypyrrole nanocomposites without dopant (SiO2/PPy) and with oxalate dopant (SiO2/PPyOx) were synthesized using polymerization of pyrrole in the presence of nano SiO2. Synthesized SiO2/PPy and SiO2/PPyOx were characterized by FTIR, SEM, TEM and EDX and their electrical conductivities were determined by CV method through the two-point-electrode without electrolyte. The corrosion protection performance of polyvinylbutyral (PVB) coatings containing SiO2/PPyOx was evaluated and compared with that of pure PVB coatings and of PVB coatings containing SiO2/PPy by electrochemical impedance spectroscopy and adhesion measurement. The results show that electrical conductivities of SiO2/PPy and SiO2/PPyOx were 0.181 and 0.109 S/cm, respectively. The ratio of PPy on SiO2 in SiO2/PPy and SiO2/PPyOx composites was 0.77/1 and the ratio of oxalate on PPy in SiO2/PPyOx composite was 1.24/1. SiO2/PPy and SiO2/PPyOx improved corrosion resistance and adhesion of PVB coatings. The presence of oxalate in SiO2/PPyOx significantly enhanced the effect of SiO2/PPy on the protection performance of PVB coatings.

  15. Corrosion-resistant multilayer coatings for the 28-75 nm wavelength region

    Energy Technology Data Exchange (ETDEWEB)

    Soufli, R; Fernandez-Perea, M; Al, E T

    2011-11-08

    Corrosion has prevented use of SiC/Mg multilayers in applications requiring good lifetime stability. We have developed Al-based barrier layers that dramatically reduce corrosion, while preserving high reflectance and low stress. The aforementioned advances may enable the implementation of corrosion-resistant, high-performance SiC/Mg coatings in the 28-75 nm region in applications such as tabletop EUV/soft x-ray laser sources and solar physics telescopes. Further study and optimization of corrosion barrier structures and coating designs is underway.

  16. Corrosion Resistance of Electroless Ni-Cu-P Ternary Alloy Coatings in Acidic and Neutral Corrosive Mediums

    Directory of Open Access Journals (Sweden)

    Mbouillé Cissé

    2010-01-01

    Full Text Available Electroless Ni-Cu-P alloy coatings were deposited on the ordinary steel substrate in an acidic hypophosphite-type plating bath. These coatings were characterized by a scanning electron microscope (SEM and an X-ray diffraction. The micrograph shows that coating presents a nodular aspect and is relatively homogeneous and very smooth. The EDX analysis shows that the coating contains 12 wt.% of phosphorus element with a predominance of nickel element. In addition, the anticorrosion properties of the Ni-Cu-P coatings in 1 M HCl, 1 M H2SO4, and 3% NaCl solutions were investigated using Tafel polarization curves, electrochemical impedance spectroscopy, and SEM/EDX analysis. The result showed a marginal improvement in corrosion resistance in 3% NaCl solution compared to acidic medium. It also showed that the corrosion mechanism depends on the nature of the solution.

  17. 2D Heterostructure coatings of hBN-MoS2 layers for corrosion resistance

    Science.gov (United States)

    Vandana, Sajith; Kochat, Vidya; Lee, Jonghoon; Varshney, Vikas; Yazdi, Sadegh; Shen, Jianfeng; Kosolwattana, Suppanat; Vinod, Soumya; Vajtai, Robert; Roy, Ajit K.; Sekhar Tiwary, Chandra; Ajayan, P. M.

    2017-02-01

    Heterostructures of atomically thin 2D materials could have improved physical, mechanical and chemical properties as compared to its individual components. Here we report, the effect of heterostructure coatings of hBN and MoS2 on the corrosion behavior as compared to coatings employing the individual 2D layer compositions. The poor corrosion resistance of MoS2 (widely used as wear resistant coating) can be improved by incorporating hBN sheets. Depending on the atomic stacking of the 2D sheets, we can further engineer the corrosion resistance properties of these coatings. A detailed spectroscopy and microscopy analysis has been used to characterize the different combinations of layered coatings. Detailed DFT based calculation reveals that the effect on the electrical properties due to atomic stacking is one of the major reasons for the improvement seen in corrosion resistance.

  18. Corrosion and Nano-mechanical Behaviors of Magnetron Sputtered Al-Mo Gradient Coated Steel

    Science.gov (United States)

    Venugopal, A.; Srinath, J.; Ramesh Narayanan, P.; Sharma, S. C.; Venkitakrishnan, P. V.

    2017-01-01

    A gradient three-layer Al-Mo coating was deposited on steel using magnetron sputtering method. The corrosion and nano-mechanical properties of the coating were examined by electrochemical impedance spectroscopy and nano-indentation tests and compared with the conventional electroplated cadmium and IVD aluminum coatings. Electrochemical impedance spectroscopy was performed by immersing the coated specimens in 3.5% NaCl solution, and the impedance behavior was recorded as a function of immersion time. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The adhesion resistance of the coatings was evaluated by scratch tests on the coated surface using nano-indentation method. The results show that the gradient Al-Mo coating exhibits better corrosion resistance than the other coatings in view of the better microstructure. The impedance results were modeled using appropriate electrical equivalent circuits for all the coated systems. The uniform, smooth and dense Al-Mo coating obtained by magnetron sputtering exhibits good adhesion with the steel substrate as per scratch test method. The poor corrosion resistance of the later coatings was shown to be due to the defects/cracks as well as the lesser adhesion of the coatings with steel. The hardness and elastic modulus of the Al-Mo coating are found to be high when compared to the other coatings.

  19. Silver deposition on polypyrrole films electrosynthesised onto Nitinol alloy. Corrosion protection and antibacterial activity.

    Science.gov (United States)

    Saugo, M; Flamini, D O; Brugnoni, L I; Saidman, S B

    2015-11-01

    The electrosynthesis of polypyrrole films onto Nitinol from sodium salicylate solutions of different concentrations is reported. The morphology and corrosion protection properties of the resulting coatings were examined and they both depend on the sodium salicylate concentration. The immobilisation of silver species in PPy films constituted by hollow rectangular microtubes was studied as a function of the polymer oxidation degree. The highest amount of silver was deposited when the coated electrode was prepolarised at -1.00V (SCE) before silver deposition, suggesting an increase in the amount of non-oxidised segments in the polymer. Finally, the antibacterial activity of the coating against the Gram positive Staphylococcus aureus and Staphylococcus epidermidis bacteria was evaluated. Both strains resulted sensitive to the modified coatings, obtaining a slightly better result against S. aureus. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    Science.gov (United States)

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  1. Effect of Sr on the bioactivity and corrosion resistance of nanoporous niobium oxide coating for orthopaedic applications.

    Science.gov (United States)

    Pauline, S Anne; Rajendran, N

    2014-03-01

    In this study, strontium incorporated Nb2O5 was synthesized in two different proportions by sol-gel methodology and was deposited on 316L SS by spin coating method. The synthesis conditions were optimized to obtain a nanoporous morphology. The prepared Sr-incorporated Nb2O5 coatings were uniform, smooth and well adherent on to the substrate 316L SS. The coatings were characterized by attenuated total reflectance-infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of Sr-incorporated Nb2O5 coatings with nanoporous morphology was confirmed. Static water contact angle measurements showed an enhancement in the wettability of the obtained coatings. In vitro bioactivity test of the coated substrates showed that 0.05M Sr-incorporated Nb2O5 coating had better bioactivity compared to 0.1M Sr-incorporated coating. Solution analysis studies confirmed the controlled release of Sr ions from the coating, which aid and enhance hydroxyapatite (HAp) growth. Electrochemical studies confirmed that the coatings provided excellent corrosion protection to the base material as increased charge transfer resistance and decreased double layer capacitance was observed for the coated substrates. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. The effects of RE and Si on the microstructure and corrosion resistance of Zn–6Al–3Mg hot dip coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shiwei [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Gao, Bo, E-mail: surfgao@aliyun.com [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Yin, Shaohua [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Tu, Ganfeng; Zhu, Guanglin; Sun, Shuchen; Zhu, Xiaoping [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China)

    2015-12-01

    Highlights: • ZAM coating has been prepared by using an experimental hot-dip galvanizing simulator. • The corrosion resistance of ZAM coating can be improved by additions of Si and RE. • Zn–6Al–3Mg–Si–RE coating forms a dense and stabilized corrosion product layer. • Zn–6Al–3Mg–Si–RE coating shows uniform corrosion. - Abstract: The effects of Si and RE on the microstructure and corrosion resistance of Zn–6Al–3Mg coating (ZAM) have been investigated. Surface morphology observations of the coating and corrosion products reveal that the additions of Si and rare earth metals (RES) improve the microstructural homogeneity of ZAMSR coating and stability of corrosion products formed on ZAMSR coating. Moreover, only uniform corrosion occurs in ZAMSR coating during the corrosion test, while intergranular corrosion and pitting occur in ZAM. As a result, the corrosion resistance of ZAM coating is improved by the additions of Si and RES.

  3. The corrosion resistance of 140MXC, 530AS and 560AS coatings produced by thermal spraying

    Directory of Open Access Journals (Sweden)

    Edwin Alexis López Covaleda

    2013-04-01

    Full Text Available Three commercial materials were deposited using electric arc thermal spraying: 140MXC (with Fe, W, Cr, Nb, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel. The aim of this paper was to evaluate the best strategy for improving a coating-substrate system’s corrosion resistance, using the following combinations: homogeneous single coatings, bilayers consisting of 530AS or 560AS under 140MXC and 140MXC + 530AS and 140MXC + 560AS coatings deposited simultaneously. The coatings were characterised using optical microscopy, scanning electron microscopy and X-ray diffraction. Corrosion resistance was evaluated through potentiodynamic polarisation and hardness by using the Vickers test. Corrosion resistance depends on the amount of microstructure defects, the deposition strategy and the alloy elements. However, corrosion resistance was similar in single coatings of 140MXC and bilayers, having -630 V corrosion potential and 708 nA corrosion current. The details and corrosion mechanism of the coatings so produced are described in this paper.

  4. Protective Performance of Polyaniline-Sulfosalicylic Acid/Epoxy Coating for 5083 Aluminum.

    Science.gov (United States)

    Liu, Suyun; Liu, Li; Meng, Fandi; Li, Ying; Wang, Fuhui

    2018-02-13

    Epoxy coatings incorporating different content of sulfosalicylic acid doped polyaniline (PANI-SSA) have been investigated for corrosion protection of 5083 aluminum alloy in 3.5% NaCl solution. The performance of the coatings is studied using a combination of electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), gravimetric tests, adhesion tests, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the content of PANI-SSA not only affects the coating compactness and the transportation of aggressive medium, but also has a significant influence on the-based aluminum. The coating with 2 wt. % PANI-SSA exhibits the best corrosion inhibition due to its good protective properties and the formation of a complete PANI-SSA induced oxide layer.

  5. 46 CFR 129.210 - Protection from wet and corrosive environments.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 129.210... ELECTRICAL INSTALLATIONS General Requirements § 129.210 Protection from wet and corrosive environments. (a... exposed to corrosive environments must be of suitable construction and must be resistant to corrosion. ...

  6. Investigation on the Cathodic Protection Effect of Low Pressure Cold Sprayed AlZn Coating in Seawater via Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Guosheng Huang

    2017-07-01

    Full Text Available Cold spray can deposit a composite coating simply by spraying mechanically-mixed Al and Zn powders, while no quantitative data has been reported on the anti-corrosion performance of different composite cold-sprayed coatings. In the present work, the finite element method was used to estimate the cathodic protection effect by simulating the potential distribution on a damaged cold-sprayed AlZn coating on Q235 steel. The results indicate that AlZn coating can only provide a limiting cathodic protection for substrate, because it can only polarize a very narrow zone negative to −0.78 V (vs. SCE, saturated calomel electrode. The remaining area of the steel substrate still has a very high residual corrosion rate. Computational methods can be used to predict the corrosion rate of AlZn coating, and the simulation results were validated by the results of a weight loss experiment.

  7. On Degradation of Cast Iron Surface-Protective Paint Coat Joint

    Directory of Open Access Journals (Sweden)

    Tupaj M.

    2016-09-01

    Full Text Available The paper is a presentation of a study on issues concerning degradation of protective paint coat having an adverse impact on aesthetic qualities of thin-walled cast-iron castings fabricated in furan resin sand. Microscopic examination and microanalyses of chemistry indicated that under the coat of paint covering the surface of a thin-walled casting, layers of oxides could be found presence of which can be most probably attributed to careless cleaning of the casting surface before the paint application process, as well as corrosion pits evidencing existence of damp residues under the paint layers contributing to creation of corrosion micro-cells

  8. An electrochemical evaluation of new materials and methods for corrosion protection

    Science.gov (United States)

    Kus, Esra

    An electrochemical evaluation of various electrode/electrolyte systems was performed by means of electrochemical impedance spectroscopy (EIS) and other techniques. Each chapter in this thesis presents an individual project with a specific objective which serves an ultimate goal of finding better materials and methods of corrosion protection. An overview of new environmentally friendly and cost effective materials and corrosion protection methods is given in Chapter 1. The protective properties of non-toxic, environmentally friendly polymer coatings, which were developed in the purpose of minimizing biofouling and providing corrosion protection on steel, were investigated and discussed in Chapter 2. The corrosion resistance of steel panels coated with crosslinked siloxanes was evaluated using EIS. Differences in protective properties of the coatings were observed due to differences in the degree of fluorination, the way the films were cured and also the degree of crosslinking. In Chapter 3, a comparison of the corrosion behavior of nanocrystalline (NC) Al 5083 with that of the conventional alloy was made in order to determine what differences if any could be attributed to the NC microstructure. Pit growth rates decreased with time for both materials based on the analysis of the impedance spectra as a function of time. NC samples were resistant to intergranular corrosion whereas conventional Al 5083 was not. The concept of the bacterial battery is presented in Chapter 4. A galvanic cell with Cu and Al 2024 and an electrolyte containing Shewanella oneidensis MR-1 in a growth medium was prepared. A control cell, which did not contain the bacteria, was also tested. For the cell with MR-1 the maximum power values increased continuously with time, whereas in the control cell the maximum power output was obtained in the first day of exposure. The objective of the study presented in Chapter 5 was to examine the interaction of MR-1 with different metal surfaces in order to

  9. Ceria based protective coatings for steel interconnects prepared by spray pyrolysis

    DEFF Research Database (Denmark)

    Szymczewska, Dagmara; Molin, Sebastian; Chen, Ming

    2014-01-01

    Stainless steels can be used in solid oxide fuel/electrolysis stacks as interconnects. For successful long term operation they require protective coatings, that lower the corrosion rate and block chemical reactions between the interconnect and adjacent layers of the oxygen or the hydrogen electrode...

  10. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.

    2005-01-01

    of deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects...

  11. Wettability and Corrosion Behavior of Chemically Modified Plasma Electrolytic Oxidation Nanocomposite Coating

    Science.gov (United States)

    Farhadi, S. S.; Aliofkhazraei, M.; Barati Darband, Gh.; Abolhasani, A.; Sabour Rouhaghdam, A.

    2017-10-01

    The aim of this paper was to investigate the effect of potassium stearate on the wettability behavior, corrosion resistance, roughness and thickness of reinforced and unreinforced plasma electrolytic oxidation (PEO) coatings with Si3N4 nanopowders. Morphological characteristic, corrosion behavior and wetting properties of the coatings were evaluated using SEM, cyclic polarization and Wilhelmy plate method, respectively. In order to obtain a better evaluation of the contact angle, roughness of the coatings was studied by AFM. The results indicated that the nanocomposite hydrophobic coatings have the best corrosion resistance. Potassium stearate could repel water from the holes of coating by reacting with aluminum and producing aluminum stearate. The contact angle of nanocomposite and normal PEO coatings was increased up to 65° due to the addition of potassium stearate. This additive could also increase the hysteresis contact angle up to 51°.

  12. Electrodeposition and Corrosion Resistance Properties of Zn-Ni/TiO2 Nano composite Coatings

    Directory of Open Access Journals (Sweden)

    B. M. Praveen

    2011-01-01

    Full Text Available Nano sized TiO2 particles were prepared by sol-gel method. TiO2 nano particles were dispersed in zinc-nickel sulphate electrolyte and thin film of Zn-Ni-TiO2 composite was generated by electrodeposition on mild steel plates. The effect of TiO2 on the corrosion behavior and hardness of the composite coatings was investigated. The film was tested for its corrosion resistance property using electrochemical, weight loss, and salt spray methods. The paper revealed higher resistance of composite coating to corrosion. Microhardness of the composite coating was determined. Scanning electron microscope images and X-ray diffraction patterns of coating revealed its fine-grain nature. Average crystalline size of the composite coating was calculated. The anticorrosion mechanism of the composite coating was also discussed.

  13. Enhanced corrosion resistance by sol-gel-based ZrO{sub 2}-CeO{sub 2} coatings on magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Phani, A.R.; Haefke, H. [Micro and Nanomaterials Section, CSEM Swiss Center for Electronics and Microtechnology, Inc., Rue Jaquet-Droz 1, CH-2007 Neuchatel (Switzerland); Gammel, F.J.; Hack, T. [EADS Deutschland GmbH, Corporate Research Center Germany, D-81663 Munich (Germany)

    2005-02-01

    The physical, chemical and mechanical properties of magnesium alloys make them attractive materials for automotive and aerospace applications. However, these materials are susceptible to corrosion and wear. This work discusses the potential of using sol-gel based coatings consisting of ZrO{sub 2} and 15 wt.% of CeO{sub 2}. The CeO{sub 2} component provides enhanced corrosion protection, while ZrO{sub 2} impart corrosion as well as wear resistance. Coating deposition was performed by the dip coating technique on two magnesium alloy substrates with different surface finishes: AZ91D (as-casted, sand-blasted, and machined) and AZ31 (rolled and machined). All as-deposited coatings (xerogel coatings) were then subjected to 10 h annealing: a temperature of 180 C was applied to the AZ91D alloy and 140 C to the AZ31 alloy. Morphological and structural properties of the annealed coatings were investigated by scanning electron microscopy, atomic force microscopy and transmission electron microscopy. Coating composition was examined using energy dispersive X-ray analysis. Adhesion of the annealed ZrO{sub 2}-CeO{sub 2} coatings on the substrates, assessed by scratch tests, showed critical loads indicative of coating perforation of up to 32 N. Hardness and elasticity, measured using depth-sensing nanoindentation tests, gave a hardness and elastic modulus of 4.5 GPa and 98 GPa, respectively. Salt spray corrosion tests performed on these coatings showed superior corrosion resistance for AZ91D (as-casted and machined) and AZ31 (machined), while severe corrosion was observed for the AZ31 (rolled) and AZ91D (sand-blasted) magnesium alloy substrates. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  14. HYDROTHERMALLY SELF-ADVANCING HYBRID COATINGS FOR MITIGATING CORROSION OF CARBON STEEL.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA, T.

    2006-11-22

    Hydrothermally self-advancing hybrid coatings were prepared by blending two starting materials, water-borne styrene acrylic latex (SAL) as the matrix and calcium aluminate cement (CAC) as the hydraulic filler, and then their usefulness was evaluated as the room temperature curable anti-corrosion coatings for carbon steel in CO{sub 2}-laden geothermal environments at 250 C. The following two major factors supported the self-improving mechanisms of the coating during its exposure in an autoclave: First was the formation of a high temperature stable polymer structure of Ca-complexed carboxylate groups containing SAL (Ca-CCG-SAL) due to hydrothermal reactions between SAL and CAC; second was the growth with continuing exposure time of crystalline calcite and boehmite phases coexisting with Ca-CCG-SAL. These two factors promoted the conversion of the porous microstructure in the non-autoclaved coating into a densified one after 7 days exposure. The densified microstructure not only considerably reduced the conductivity of corrosive ionic electrolytes through the coatings' layers, but also contributed to the excellent adherence of the coating to underlying steel' s surface that, in turn, retarded the cathodic oxygen reduction reaction at the corrosion site of steel. Such characteristics including the minimum uptake of corrosive electrolytes by the coating and the retardation of the cathodic corrosion reaction played an important role in inhibiting the corrosion of carbon steel in geothermal environments.

  15. Effect of heat treatment, top coatings and conversion coatings on the corrosion properties of black electroless Ni-P films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y., E-mail: liu_yunli@hotmail.com [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom); Beckett, D.; Hawthorne, D. [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom)

    2011-02-15

    Electroless black nickel-phosphorus plating is an advanced electroless nickel plating process formulated to deposit a black finish when processed through an oxidizing acid solution. Heat treatment, five types of top organic coating techniques and one conversion coating technique with three different experimental conditions were investigated to stabilize the black film and increase the hardness and corrosion resistance. Morphology and compositions of electroless nickel-phosphorous films with or without heat treatment, with five types of top organic coatings, and with three conversion coatings were compared to examine nickel, phosphorus, oxygen, carbon, silicon and chrome contents on the corrosion resistance of black surfaces by energy dispersive X-ray microanalysis and scanning electron microscope. Corrosion resistance of black electroless nickel-phosphorus coatings with or without heat treatment, with five types of top organic coatings, and with three conversion coatings was investigated by the polarization measurements and the salt spray test in 5% NaCl solution, respectively. HydroLac as the top organic coating from MacDermid showed the excellent corrosion resistance and the black EN film did not lose the black color after 48 h salt spray test. Electrotarnil B process with 0.5 ASD for 1 min stabilized the black Ni-P film immediately and increased the hardness and corrosion performance of the black Ni-P film. The black Ni-P coating with Electroarnil B process passed the 5% NaCl salt spray test for 3000 h in the black color and had a minimal corrosion current 0.8547 {mu}A/cm{sup 2} by the polarization measurement.

  16. Corrosion resistance and adhesion strength of a spin-assisted layer-by-layer assembled coating on AZ31 magnesium alloy

    Science.gov (United States)

    Zhao, Yan-Bin; Liu, Han-Peng; Li, Chang-Yang; Chen, Yong; Li, Shuo-Qi; Zeng, Rong-Chang; Wang, Zhen-Lin

    2018-03-01

    A polyvinylpyrrolidone (PVP)/polyacrylic acid (PAA) layer-by-layer (LbL) assembled composite coating with a multilayer structure for the corrosion protection of AZ31 magnesium alloy was prepared by a novel spin-casting method. The microstructure and composition of this coating were investigated by means of SEM, XRD and FT-IR measurements. Moreover, electrochemical, immersion and scratch tests in vitro were performed to measure the corrosion performance and the adhesion strength. These results indicated that the (PVP/PAA)10 composite coating with defect-free, dense and uniform morphologies could be successfully deposited on the surface of magnesium alloy. The coating had excellent corrosion resistance and adhesion strength.

  17. Electrochemical impedance spectroscopy (EIS) as a tool for measuring corrosion of polymer-coated fasteners used in treated wood

    Science.gov (United States)

    Samuel L. Zelinka; Lorraine Ortiz-Candelaria; Donald S. Stone; Douglas R. Rammer

    2009-01-01

    Currently, many of the polymer-coated fasteners on the market are designed for improved corrosion performance in treated wood; yet, there is no way to evaluate their corrosion performance. In this study, a common technique for measuring the corrosion performance of polymer-coated metals, electrochemical impedance spectroscopy (EIS), was used to evaluate commercial...

  18. Estudo das características de revestimentos poliméricos aplicados por aspersão térmica para proteção contra desgaste e corrosão de substratos metálicos Study of the characteristics of thermally sprayed polymer coatings for wear and corrosion protection of metallic substrates

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Camello Lima

    2012-12-01

    Full Text Available Revestimentos poliméricos vêm sendo crescentemente considerados como solução na proteção de materiais metálicos contra corrosão e desgaste. A tecnologia de aspersão térmica permite a aplicação de polímeros sobre diversos materiais de substrato, em diversas espessuras, para várias condições ambientais. Polímeros depositados por este processo têm potencial, tanto para reduzir custos com materiais, como para melhorar o desempenho do revestimento em ambientes agressivos. Neste trabalho, foram aplicados revestimentos poliméricos poli-éter-éter-cetona (PEEK e Poliamida 12 sobre substratos de aço carbono, utilizando o processo de aspersão térmica a chama de baixa velocidade. Revestimentos de alta qualidade foram obtidos por esta técnica. Foram avaliadas as características dos materiais e dos revestimentos obtidos, especialmente quanto às propriedades mecânicas, de desgaste e corrosão. De acordo com os resultados obtidos, pode-se afirmar que os revestimentos estudados podem ser utilizados com sucesso em aplicações que envolvam desgaste e corrosão, com uma pequena vantagem para o polímero PEEK.Polymer coatings have been widely considered as a solution in the protection of metallic substrates against both wear and corrosion. Thermal spray technology allows the deposition of polymers onto several substrate materials for various thicknesses at several environmental conditions. Thermal sprayed polymers have high potential for material cost reduction as well as to improve coating performance in drastic environments. In this work, poly-ether-ether-ketone (PEEK and Polyamide 12 were flame sprayed on carbon steel substrates. High quality coatings were obtained. Several tests were carried out to evaluate the coatings mainly related to wear and corrosion performance. According to the obtained results, it can be stated that the studied coatings can be successfully used in applications involving wear and corrosion, with a slight edge

  19. 40 CFR 280.31 - Operation and maintenance of corrosion protection.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Operation and maintenance of corrosion... protection. All owners and operators of steel UST systems with corrosion protection must comply with the... is used to store regulated substances: (a) All corrosion protection systems must be operated and...

  20. Protective coatings based on 2D-materials

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten

    Corrosion has a major impact on the world economy. Barrier coatings is one of the most widely applied strategies to reduce the degradation of materials, however, every coating technology has its drawbacks. Graphene has the potential of creating the ideal coating, being atomically thin and, when...... in perfect condition, impermeable to most molecules. However, it has recently been demonstrated that graphene can promote galvanic corrosion and may actually increase the corrosion rate in the long term. The aim of this thesis is to individuate, develop and demonstrate solutions based on 2Dmaterials...

  1. Corrosion Resistance of Nanosized Silicon Carbide-Rich Composite Coatings Produced by Noble Gas Ion Mixing.

    Science.gov (United States)

    Racz, A S; Kerner, Z; Nemeth, A; Panjan, P; Peter, L; Sulyok, A; Vertesy, G; Zolnai, Z; Menyhard, M

    2017-12-27

    Ion beam mixing has been used to produce a silicon carbide (SiC)-rich nanolayer for protective coating. Different C/Si/C/Si/C/Si(substrate) multilayer structures (with individual layer thicknesses falling in the range of 10-20 nm) have been irradiated by Ar+ and Xe+ ions at room temperature in the energy and fluence ranges of 40-120 keV and 1-6 × 1016 ion/cm2, respectively. The effects of ion irradiation, including the in-depth distribution of the SiC produced, was determined by Auger electron spectroscopy depth profiling. The thickness of the SiC-rich region was only some nanometers, and it could be tailored by changing the layer structure and the ion irradiation conditions. The corrosion resistance of the layers was investigated by potentiodynamic electrochemical test in 4 M KOH solution. The measured corrosion resistance of the SiC-rich layers was orders of magnitude better than that of pure silicon, and a correlation was found between the corrosion current density and the effective areal density of the SiC.

  2. Improved Corrosion Resistance of a Heat Exchanger Using a Copper Tube Coated with Tin

    National Research Council Canada - National Science Library

    FUKUSHIMA, Makoto; YONESAKI, Takahiro; TAKIZAWA, Kikuo; SUSAI, Takashi

    2000-01-01

      The outer face of copper tubes used in a heat exchanger were coated with tin. The tubes were brazed with various types of solder in order to evaluate their corrosion resistance in a H2S gas environment...

  3. Coated steel rebar for enhanced concrete-steel bond strength and corrosion resistance.

    Science.gov (United States)

    2010-10-01

    This report summarizes the findings and recommendations on the use of enamel coating in reinforced concrete structures both for bond strength and : corrosion resistance of steel rebar. Extensive laboratory tests were conducted to characterize the pro...

  4. Sol-Gel Coating on Magnesium Alloy and Its Evaluation of Corrosion Resistance

    National Research Council Canada - National Science Library

    Hitonori SATO; Shinji HIRAI; Kazuyoshi SHIMAKAGE; Kenji WADA

    2003-01-01

    .... In comparisons between the composite films prepared by repeating three dip-coatings and an anodic oxide film of magnesium alloy, the acidic corrosion resistances of these films to various acids...

  5. Microstructure and Corrosion Resistance of Aluminium and Copper Composite Coatings Deposited by LPCS Method

    Directory of Open Access Journals (Sweden)

    Winnicki M.

    2016-12-01

    Full Text Available The paper presents the study of microstructure and corrosion resistance of composite coatings (Al+Al2O3 and Cu+Al2O3 deposited by Low Pressure Cold Spraying method (LPCS. The atmospheric corrosion resistance was examined by subjecting the samples to cyclic salt spray and Kesternich test chambers, with NaCl and SO2 atmospheres, respectively. The selected tests allowed reflecting the actual working conditions of the coatings. The analysis showed very satisfactory results for copper coatings. After eighteen cycles, with a total time of 432 hours, the samples show little signs of corrosion. Due to their greater susceptibility to chloride ions, aluminium coatings have significant corrosion losses.

  6. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gopala N. Krishnan; Ripudaman Malhotra; Jordi Perez; Marc Hornbostel; Kai-Hung Lau; Angel Sanjurjo

    2007-05-31

    {approx}20%Cr and Al each can be resistant to sulfidation attack for 500 h. However, exposure to an actual coal gasifier gas stream at the Wabash River gasifier facility for 1000 h in the temperature range 900 to 950 C indicated that Cr and Al present in the coating diffused further into the substrate decreasing the protective ability of these elements against attack by H{sub 2}S. Similarly, adherent multilayer coatings containing Si, Ti, Al, and Nb were also deposited with subsequent nitridation of these elements to increase the corrosion resistance. Both dense and porous SS409 or SS 410 alloy substrates were coated by using this method. Multilayer coatings containing Ti-Al-Si nitrides along with a diffusion barrier of Nb were deposited on SS410 and they were found also to be resistant to sulfidation attack in the bench scale tests at 900 C. However, they were corroded during exposure to the actual coal gasifier stream at the Wabash River gasifier facility for 1000 h. The Cr/Al coatings deposited inside a porous substrate was found to be resistant to sulfidation attack in the bench-scale simulated tests at 370 C. The long-term exposure test at the Wabash River gasifier facility at 370 C for 2100 h showed that only a minor sulfidation attack occurred inside the porous SS 409 alloy coupons that contained Cr and Al diffusion coatings. This attack can be prevented by improving the coating process to deposit uniform coatings at the interior of the porous structure. It is recommended that additional studies be initiated to optimize the FBR-CVD process to deposit diffusion coatings of the corrosion resistant elements such as Cr, Al, and Ti inside porous metal filters to increase their corrosion resistance. Long-term exposure tests using an actual gas stream from an operating gasifier need to be conducted to determine the suitability of the coatings for use in the gasifier environment.

  7. Corrosion Inhibition on SAE 1010 Steel by Nanoscale Exopolysaccharides Coatings Determined by Electrochemical and Surface Characterization

    Science.gov (United States)

    Plating, painting and the application of enamel are the most common anti-corrosion treatments. They are effective by providing a barrier of corrosion resistant material between the damaging environment and the structural material. Coatings start failing rapidly if scratched or damaged because a co...

  8. Corrosion behaviour of hot dip zinc and zinc–aluminium coatings on ...

    Indian Academy of Sciences (India)

    Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China. MS received 2 March 2001; revised 1 June 2001 ... ing severe marine environment in China, to evaluate the corrosion resistance of the three types of ... products and reweighed to determine loss of coating due to corrosion. To facilitate direct ...

  9. Corrosion resistant Zn–Co alloy coatings deposited using saw-tooth ...

    Indian Academy of Sciences (India)

    ... and electrochemical impedance spectroscopy (EIS) method. Optimal configuration, represented as (Zn–Co)2.0/4.0/300 was found to exhibit ∼ 89 times better corrosion resistance compared to monolithic (Zn–Co)3.0 alloy deposited for same time, from same bath. The better corrosion resistance of CMMA coatings was ...

  10. In vivo corrosion and corrosion protection of magnesium alloy LAE442.

    Science.gov (United States)

    Witte, F; Fischer, J; Nellesen, J; Vogt, C; Vogt, J; Donath, T; Beckmann, F

    2010-05-01

    The aim of this study was to investigate whether the extruded magnesium alloy LAE442 reacts in vivo with an appropriate host response and to investigate how an additional magnesium fluoride (MgF(2)) coating influences the in vivo corrosion rate. Forty cylinders were machined from extruded LAE442 and 20 of these were coated additionally with MgF(2) and implanted into the medial femur condyle of adult rabbits. Synchrotron-radiation-based X-ray computed micro-tomography (SRmicroCT) was used to quantitatively analyse corrosion non-destructively in vivo and comparisons were made to magnesium degradation rates based on area measurements of the remaining metal on uncalcified sections. Blood concentrations of the alloying elements were measured below toxicological limits. The MgF(2) layer was no longer detected after 4 weeks of implantation by particle-induced gamma emission, and the MgF(2) coating reduced the blood content of alloying elements during the first 6 weeks of implantation with no elevated fluoride concentration in the adjacent bone. Histopathological examinations of liver showed in 9 out of 40 cases minimal infiltrations of heterophil granulocytes of unknown origin (5 LAE442, 4 LAE442+MgF(2)). The kidneys were mainly regular in structure. The synovial tissue showed a granular cell infiltration as a temporary observation in the LAE442+MgF(2) group after 2 weeks. No subcutaneous gas cavities were observed clinically and on postoperative X-rays in all animals. All specimens were scanned by SRmicroCT at 2, 4, 6 and 12 weeks postoperatively before uncalcified sections were performed. All magnesium implants have been observed in direct bone contact and without a fibrous capsule. Localized pitting corrosion occurred in coated and uncoated magnesium implants. This study shows that the extruded magnesium alloy LAE442 provides low corrosion rates and reacts in vivo with an acceptable host response. The in vivo corrosion rate can be further reduced by additional MgF(2

  11. A Study on the Corrosion and Wear Behavior of Electrodeposited Ni-W-P Coating

    Science.gov (United States)

    Lee, Hung Bin; Wu, Meng Yen

    2017-10-01

    In this study, the tribocorrosion of electroplated Ni-W-P alloy coating (3.9 to 4.3 at. pct W and 13.1 to 14.7 at. pct P) on a cylindrical copper substrate was investigated using a block-on-ring tester. The wear and corrosion performance of the coating and their synergic effect were measured at different overpotentials. Under simple immersion corrosion conditions with an increasing overpotential from open-circuit potential to +400 mVSCE, the surface of the coating initially showed no obvious corrosion, eventually developing pitting holes that subsequently enlarged and showing the spreading of cracks. The corrosion products were a mixture of NiO, WO3, and phosphate, and the corroded surface was P-rich, porous, and less crystalline than the pristine coating. Corrosion and mechanical wear had little influence on tribocorrosion at low overpotential values. However, the synergic effect drastically became stronger at high overpotentials. The surface was full of large pitting holes and grooves. The weight loss due to the corrosion component increased linearly with the overpotential but was limited in comparison with the wear component, which was the main cause of weight loss. On the other hand, the friction coefficient first increased and then decreased with an increase in overpotential. Both the surface morphology of the corroded coating and the thickness of the corrosion oxide play important roles in this friction characteristic.

  12. Corrosion behavior of Cr/Ni alloy coated ferritic stainless steel in simulated cathodic PEMFC environments

    Energy Technology Data Exchange (ETDEWEB)

    Rendon, M.; Rivas, S.V.; Arriga, L.G.; Orozco, G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Queretaro (Mexico); Perez-Quiroz, J.T. [Inst. Mexicano del Transporte, Queretaro (Mexico); Porcayo, J. [Inst. de Investigaciones Electricas, Morelos (Mexico)

    2008-07-01

    The bipolar plate in a proton exchange membrane fuel cell (PEMFC) must be corrosion resistant and the interfacial contact resistance (ICR) with the gas diffusion layer must be low. For these reasons, stainless steel with high Cr content is considered to be a viable material for use in bipolar plate construction. This study evaluated the corrosion resistance of ferritic stainless steels 441 and 439, with and without a Cr/Ni coating, under simulated cathodic PEMFC conditions. Steel 441 without coating has a low corrosion current density and can be considered as a candidate material to be used as bipolar plate. The study showed that after the Cr/Ni coating was applied by Thermal Spray Metal method, the corrosion current density increased due to selective dissolution of an alloy element. The corrosion current density of the coatings was higher than the DOE target value, rendering them an unfeasible option to be used in bipolar plates for fuel cell applications. However, previous studies have shown that after the coating was applied, a passivation process improved the corrosion resistance. Although steel 441 appears to be a better candidate than steel 316 because of its lower cost, the behaviour of the Ni-Cr alloys was not satisfactory in corrosive acidic medium. 5 refs.

  13. Influence of coating defects on the corrosion behavior of cold sprayed refractory metals

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S., E-mail: skumar@arci.res.in; Rao, A. Arjuna

    2017-02-28

    Highlights: • Long duration immersion tests reveal inhomogeneous weight losses. • The weight loss for different coatings are well corroborated with the coating defects. • Chemical and micro structural analysis elucidates the reason behind the in homogeneous performance of different type of cold sprayed coatings. • In cold sprayed titanium, formation of oxide along the inter-splat boundary hinders the aggressive attack of the medium. - Abstract: The defects in the cold sprayed coatings are critical in the case of corrosion performances of the coatings in aggressive conditions. To understand the influence of coating defects on corrosion, immersion tests have been carried out in HF solution for the cold sprayed and heat treated Titanium, Tantalum and Niobium coatings. Long duration immersion tests reveal inhomogeneous weight losses of the samples prepared at different heat treatment conditions. The weight loss for different coatings has been well corroborated with the coating defects and microstructures. Chemical and micro structural analysis elucidates the reason behind the inhomogeneous performance of different type of cold sprayed coatings in corrosion medium. In the case of cold sprayed titanium, formation of stable oxide along the inter-splat boundary hinders the aggressive attack of the corrosion medium which is not so in other cases.

  14. Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids

    Directory of Open Access Journals (Sweden)

    Nataly Ce

    2016-11-01

    Full Text Available This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA on carbon steel. Small defects (4% of the sample’s geometric surface area were drilled, exposing the steel, and the performance of the coating was analyzed for corrosion potential for different exposure times (2 h, 335 h, and 5000 h. The samples were monitored using linear polarization resistance (LPR in order to obtain their corrosion rate. Scanning electron microscopy (SEM/energy dispersive X-ray spectroscopy (EDX and X-ray diffraction (XRD were used for post-test characterization. The results showed that a protective layer of Mg(OH2 formed in the damaged area, which protected the underlying steel. Additionally, no coating detachment from the steel near the defect region was observed. The corrosion rate was found to be 0.010–0.015 mm/year after 5000 h in boiling synthetic seawater.

  15. High-temperature protective coatings for C/SiC composites

    Directory of Open Access Journals (Sweden)

    Xiang Yang

    2014-12-01

    Full Text Available Carbon fiber-reinforced silicon carbide (C/SiC composites were well-established light weight materials combining high specific strength and damage tolerance. For high-temperature applications, protective coatings had to provide oxidation and corrosion resistance. The literature data introduced various technologies and materials, which were suitable for the application of coatings. Coating procedures and conditions, materials design limitations related to the reactivity of the components of C/SiC composites, new approaches and coating systems to the selection of protective coatings materials were examined. The focus of future work was on optimization by further multilayer coating systems and the anti-oxidation ability of C/SiC composites at temperatures up to 2073 K or higher in water vapor.

  16. 46 CFR 183.210 - Protection from wet and corrosive environments.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 183.210... (UNDER 100 GROSS TONS) ELECTRICAL INSTALLATION General Requirements § 183.210 Protection from wet and... corrosion-resistant. ...

  17. Corrosion protection of reinforcement by hydrophobic treatment of concrete

    NARCIS (Netherlands)

    Polder, R.B.; Vries, H. de

    1999-01-01

    Penetration of de-icing salts into concrete bridge decks may cause corrosion of reinforcement. Hydrophobic treatment of concrete was studied as additional protection. It was shown that hydrophobic treatment strongly reduces chloride ingress, during semi-permanent contact and in wetting/drying

  18. Low Toxicity Corrosion Inhibitors for Smart Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Kennedy Space Center (KSC) is located near one of the most corrosive natural environments in the world. Corrosion of KSC ground assets is exacerbated by the...

  19. COATINGS FOR PROTECTION OF EQUIPMENT FOR BIOCHEMICAL PROCESSING OF GEOTHERMAL RESIDUES: PROGRESS REPORT FY 97

    Energy Technology Data Exchange (ETDEWEB)

    ALLAN,M.L.

    1997-11-01

    Thermal sprayed ethylene methacrylic acid (EMAA) and ethylene tetrafluoroethylene (ETFE), spray-and-bake ETFE and polyvinylidene fluoride (PVDF) and brushable ceramic-epoxy coatings were evaluated for corrosion protection in a biochemical process to treat geothermal residues. The findings are also relevant to other moderate temperature brine environments where corrosion is a problem. Coupon, Atlas cell, peel strength, cathodic disbondment and abrasion tests were performed in aggressive environments including geothermal sludge, hypersaline brine and sulfur-oxidizing bacteria (Thiobadus ferrooxidans) to determine suitability for protecting storage tanks and reaction vessels. It was found that all of the coatings were resistant to chemical attack and biodegradation at the test temperature of 55 C. The EMAA coatings protected 316L stainless steel from corrosion in coupon tests. However, corrosion of mild steel substrates thermal sprayed with EMAA and ETFE occurred in Atlas cell tests that simulated a lined reactor operating environment and this resulted in decreased adhesive strength. Peel tests to measure residual adhesion revealed that failure mode was dependent on exposure conditions. Long-term tests on the durability of ceramic-epoxy coatings in brine and bacteria are ongoing. Initial indications are that this coating has suitable characteristics. Abrasion tests showed that the ceramic-epoxy had good resistance to the abrasive effects of sludge. Thermal sprayed EMAA coatings also displayed abrasion resistance. Cathodic disbondment tests in brine at room temperature indicated that EMAA coatings are resistant to disbondment at applied potentials of {minus}780 to {minus}1,070 mV SCE for the test conditions and duration. Slight disbondment of one specimen occurred at a potential of {minus}1,500 mV SCE. The EMAA may be suited to use in conjunction with cathodic protection although further long-term, higher temperature testing would be needed.

  20. Ultrasonic irradiation and its application for improving the corrosion resistance of phosphate coatings on aluminum alloys.

    Science.gov (United States)

    Sheng, Minqi; Wang, Chao; Zhong, Qingdong; Wei, Yinyin; Wang, Yi

    2010-01-01

    In this paper, ultrasonic irradiation was utilized for improving the corrosion resistance of phosphate coatings on aluminum alloys. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effect of ultrasonic irradiation on the corrosion resistance of phosphate coatings was investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Various effects of the addition of Nd(2)O(3) in phosphating bath on the performance of the coatings were also investigated. Results show that the composition of phosphate coating were Zn(3)(PO(4))(2).4H(2)O(hopeite) and Zn crystals. The phosphate coatings became denser with fewer microscopic holes by utilizing ultrasonic irradiation treatment. The addition of Nd(2)O(3) reduced the crystallinity of the coatings, with the additional result that the crystallites were increasingly nubby and spherical. The corrosion resistance of the coatings was also significantly improved by ultrasonic irradiation treatment; both the anodic and cathodic processes of corrosion taking place on the aluminum alloy substrate were suppressed consequently. In addition, the electrochemical impedance of the coatings was also increased by utilizing ultrasonic irradiation treatment compared with traditional treatment.

  1. New Anti-Corrosive Coatings with Resin-Bonded Polyaniline and Related Electroactive Groups

    Science.gov (United States)

    Weil, Edward D.

    1997-01-01

    It is already known that polyaniline (an electroactive polymer) functions as a corrosion inhibitor for steel and in view of the fact that it is known to perform in the presence of hydrochloric acid, it has been considered likely that it may be useful to NASA for protecting launch structures at KSC which are exposed to not only continual ocean-side salt spray but also to hydrochloric acid at the times that solid-fuel boosters are fired. The currently used zinc-rich silicate-bonded coating is not wholly protective against the hydrochloric acid. Water pollution from zinc salts is another concern. Other earlier and concurrent NASA sponsored projects have been focussed on polyaniline specifically. Our project, administered for NASA by Dr. K. Thompson of KSC and these more-specifically polyaniline-related projects are included in a CRADA coordinated by Dr. F. Via of Akzo Nobel. A parallel project at Polytechnic under Prof K. Levon concentrated more specifically on polyaniline with various dopants. Our exploratory project reported herein was aimed at broadening the range of such corrosion inhibitors, to give protective paint compounders a wider latitude for adding corrosion inhibitors having polyaniline-like performance, and thus we diverged in several probing directions from polyaniline. Our working hypothesis was that physical variants of polyaniline, such as supported formulations on pigments or carriers, and chemical variants of polyaniline, including those having no electroconductive character, may have enhanced anticorrosion activity. We also hypothesized that small (non-polymeric) molecules having structures related to those occurring in polyaniline, may be active as corrosion inhibitors. We did preliminary testing, using an ASTM salt spray method at a nearby commercial paint testing laboratory. Our most interesting findings were that a non-electroconductive meta-isomer of polyaniline showed some corrosion activity, suggesting that the features of the polyaniline

  2. Electrodeposition of polypyrrole onto NiTi and the corrosion behaviour of the coated alloy

    Energy Technology Data Exchange (ETDEWEB)

    Flamini, D.O. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)], E-mail: ssaidman@criba.edu.ar

    2010-01-15

    Polypyrrole (PPy) films were electrodeposited onto nickel--titanium alloy (NiTi) employing sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT or AOT) solutions. Polarizing anodically NiTi samples recovered by PPy in a monomer-free solution increases adhesion of the coating. Electrochemical techniques, scanning electron microscopy (SEM) and element analysis were used in determining the corrosion performance of the coated samples in chloride solution. The polymer improves the corrosion performance at the open circuit potential and at potentials where the bare substrate suffers pitting attack. The improvement in both, adhesion and corrosion performance, is discussed considering substrate/polymer interaction, overoxidation of PPy and the role played by AOT.

  3. Biocompatibly Coated 304 Stainless Steel as Superior Corrosion-Resistant Implant Material to 316L Steel

    Science.gov (United States)

    Paul, Subir; Mandal, Chandranath

    2013-10-01

    Surface treatments of 304 stainless steel by electro-coating and passivating in few inorganic electrolytes were found to be very effective in drastically reducing the corrosion rate of the material in stimulated body fluid (SBF) by several orders in comparison to that of 316L steel, presently being used for orthopedic implants. Polarization studies of electrodeposited hydroxyl apatite coating on 304 steel showed remarkably improved corrosion current. Cyclic polarization of the material in SBF reflected the broadened passivity region, much lower passive current, and narrower hysteresis loops. Similar effects were also found through the formation of inorganic coatings by passivation in NaF, CaNO3, and calcium phosphate buffer solutions. Surface characterization by XRD showed the peaks of the respective coating crystals. The morphology of the coatings studied by SEM showed a flake-type structure for hydroxyapatite coating and fine spherical-subspherical particles for other coatings.

  4. Multicomponent Oxide Systems for Corrosion Protection.

    Science.gov (United States)

    1980-11-15

    the dissolution of the native aluminum oxide layer and through the influence of the slight solubility difference between chromium and aluminum...generally octahedrally coordinated, although half of the cation sites in the common spinel structure are tetrahe- dral. As a general rule, one...chromate coating solutions contain chromic acid or one of its soluble salts as a source of hexavalent chromium . However, no chemical reaction with the

  5. Corrosion resistance of different metallic coatings on press-hardened steels for automotive

    Energy Technology Data Exchange (ETDEWEB)

    Dosdat, L.; Petitjean, J.; Vietoris, T. (ArcelorMittal Maizieres Automotive Products Research Centre, F-57283 Maizieres-les-Metz); Clauzeau, O. [Bohr Technologies (France)

    2011-06-15

    The corrosion resistance of laboratory press-hardened components in aluminized, galvanized or galvannealed boron steels was evaluated through VDA 621-415 cyclic test for the automotive industry. 22MnB5 uncoated steel for hot stamping and standard galvanized steel for cold forming were also included as references. Corrosion resistance after painting (cosmetic corrosion) was quantified by measuring the delamination of electro-deposited paint from scribed panels. The rusting on their edges was used for determining the cut-edge corrosion resistance. The corrosion resistance on unpainted deformed panels (perforating corrosion) was quantified by mass losses and pit depth measurements. Zinc-coated boron steels were found to be more resistant to cosmetic corrosion than the other materials, and slightly more resistant to cut-edge corrosion than the aluminized one. Red rust apparition could not be avoided due to the high iron content in all these hot-stamped coatings. The three coated boron steels showed similar performances in terms of resistance to perforation. Aluminized boron steel presents the advantage of being less sensitive to hot-stamping process deviation. Its robustness has been proved for many years on cars. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Corrosion Behavior of X80 Steel with Coupled Coating Defects under Alternating Current Interference in Alkaline Environment

    Science.gov (United States)

    Li, Zhong; Li, Caiyu; Qian, Hongchang; Li, Jun; Huang, Liang; Du, Cuiwei

    2017-01-01

    The corrosion behavior of X80 steel in the presence of coupled coating defects was simulated and studied under the interference of alternating current (AC) in an alkaline environment. The results from electrochemical measurements showed that the electrode potential of the coating defect with the smaller exposed area was lower than that with the larger area, which indicated that the steel with the smaller coating defect was more prone to corrosion. The result of weight loss tests also showed that the smaller coating defect had induced a higher corrosion rate. However, the corrosion rate of X80 steel at the larger coating defect decreased gradually with the increase of the larger defect area at a constant smaller defect area. The corrosion morphology images showed that the coating defects with smaller areas suffered from more severe pitting corrosion. PMID:28773078

  7. Corrosion Behavior of X80 Steel with Coupled Coating Defects under Alternating Current Interference in Alkaline Environment.

    Science.gov (United States)

    Li, Zhong; Li, Caiyu; Qian, Hongchang; Li, Jun; Huang, Liang; Du, Cuiwei

    2017-06-28

    The corrosion behavior of X80 steel in the presence of coupled coating defects was simulated and studied under the interference of alternating current (AC) in an alkaline environment. The results from electrochemical measurements showed that the electrode potential of the coating defect with the smaller exposed area was lower than that with the larger area, which indicated that the steel with the smaller coating defect was more prone to corrosion. The result of weight loss tests also showed that the smaller coating defect had induced a higher corrosion rate. However, the corrosion rate of X80 steel at the larger coating defect decreased gradually with the increase of the larger defect area at a constant smaller defect area. The corrosion morphology images showed that the coating defects with smaller areas suffered from more severe pitting corrosion.

  8. Bioactive hydroxyapatite/graphene composite coating and its corrosion stability in simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Janković, Ana; Eraković, Sanja [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia); Mitrić, Miodrag [Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, 11 000 Belgrade (Serbia); Matić, Ivana Z.; Juranić, Zorica D. [Institute of Oncology and Radiology of Serbia, Pasterova 14, 11 000 Belgrade (Serbia); Tsui, Gary C.P.; Tang, Chak-yin [Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Mišković-Stanković, Vesna [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11 000 Belgrade (Serbia); Rhee, Kyong Yop, E-mail: rheeky@khu.ac.kr [Department of Mechanical Engineering, Kyung Hee University, Yongin 449-701 (Korea, Republic of); Park, Soo Jin [Chemistry, College of Natural Sciences, Inha University, Incheon 402-751 (Korea, Republic of)

    2015-03-05

    Highlights: • Bioactive HAP/Gr coating on Ti was successfully obtained by EPD. • Increased fracture toughness of the HAP/Gr coating compared to pure HAP coating. • HAP/Gr coating exhibited superior biomimetic mineralization vs. pure HAP coating. • Gr improved the mechanical properties and thermal stability of HAP/Gr coating. • HAP/Gr coating was classified as non-cytotoxic against the targeted PBMC. - Abstract: The hydroxyapatite/graphene (HAP/Gr) composite was electrodeposited on Ti using the electrophoretic deposition process to obtain uniform bioactive coating with improved mechanical strength and favorable corrosion stability in simulated body fluid (SBF). Incorporation of Gr was verified by Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron analysis. The HAP/Gr composite coating exhibited reduced surface cracks, nearly double the hardness, and elastic modulus increased by almost 50% compared to pure HAP coating, as estimated by a nanoindentation test. The bioactive HAP/Gr composite coating provided a newly formed apatite layer in SBF with enhanced corrosion stability, as evidenced by electrochemical impedance spectroscopy. The thermal stability of the HAP/Gr coating was improved in comparison to the pure HAP coating, and the Ca/P ratio was closer to the stoichiometric value. No antibacterial activity against Staphylococcus aureus or Escherichia coli could be verified. The HAP/Gr composite coating was classified as non-cytotoxic when tested against healthy peripheral blood mononuclear cells (PBMC)

  9. Corrosion Properties of Polydopamine Coatings Formed in One-Step Immersion Process on Magnesium.

    Science.gov (United States)

    Singer, Ferdinand; Schlesak, Magdalena; Mebert, Caroline; Höhn, Sarah; Virtanen, Sannakaisa

    2015-12-09

    Polydopamine layers were polymerized directly from Tris(hydroxymethyl)aminomethane-buffered solution in a one-step immersion process onto magnesium surface. Scanning electron microscopy showed successful formation of a ∼1 μm thick layer. ASTM D3359-09 "Tape test" revealed excellent adhesion of the layer. X-ray induced photoelectron spectroscopy and Fourier transform infrared spectroscopy verified the presence of polydopamine on the surface. Corrosion measurements were performed in 0.1 M NaCl solution investigating the influence of coating parameters: dopamine concentration, immersion time, solution pH, and immersion angle. Tafel analysis revealed strong improvement of corrosion behavior compared to bare magnesium. Polydopamine layers prepared with optimized coating procedure showed promising corrosion properties in Dulbecco's modified Eagle medium. In summary, polydopamine coatings offer a simple treatment for magnesium to improve the corrosion behavior and could further act as intermediate layer for further surface functionalization.

  10. Properties of Lightning Strike Protection Coatings

    Science.gov (United States)

    Gagne, Martin

    Composite materials are being increasingly used by many industries. In the case of aerospace companies, those materials are installed on their aircraft to save weight, and thus, fuel costs. These aircraft are lighter, but the loss of electrical conductivity makes aircraft vulnerable to lightning strikes, which hit commercial aircrafts on average once per year. This makes lightning strike protection very important, and while current metallic expanded copper foils offer good protection, they increase the weight of composites. Therefore, under the CRIAQ COMP-502 project, a team of industrial partners and academic researchers are investigating new conductive coatings with the following characteristics: High electromagnetic protection, high mechanical resistance, good environmental protection, manufacturability and moderate cost. The main objectives of this thesis, as part of this project, was to determine the main characteristics, such as electrical and tribomechanical properties, of conductive coatings on composite panels. Their properties were also to be tested after destructive tests such as current injection and environmental testing. Bombardier Aerospace provided the substrate, a composite of carbon fiber reinforced epoxy matrix, and the current commercial product, a surfacing film that includes an expanded copper foil used to compare with the other coatings. The conductive coatings fabricated by the students are: silver nanoparticles inside a binding matrix (PEDOT:PSS or a mix of Epoxy and PEDOT:PSS), silvered carbon nanofibers embedded in the surfacing film, cold sprayed tin, graphene oxide functionalized with silver nanowires, and electroless plated silver. Additionally as part of the project and thesis, magnetron sputtered aluminum coated samples were fabricated. There are three main types of tests to characterize the conductive coatings: electrical, mechanical and environmental. Electrical tests consist of finding the sheet resistance and specific resistivity

  11. Characterization and corrosion behavior of ceramic coating on magnesium by micro-arc oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Durdu, Salih [Department of Materials Science and Engineering, Gebze Institute of Technology, Gebze, Kocaeli 41400 (Turkey); Aytac, Aylin [Gazi University, Faculty of Science, Department of Chemistry, Teknikokullar, Ankara 06500 (Turkey); Usta, Metin, E-mail: ustam@gyte.edu.tr [Department of Materials Science and Engineering, Gebze Institute of Technology, Gebze, Kocaeli 41400 (Turkey)

    2011-08-25

    Highlights: {center_dot} The commercial pure magnesium was coated by micro-arc oxidation method. {center_dot} The coating is composed of two layers, a porous outer layer and a dense inner layer. {center_dot} A super corrosion resistance was achieved with MAO coatings. {center_dot} Coating with Mg{sub 2}SiO{sub 4} is more resistant to corrosion than that containing Mg{sub 3}(PO{sub 4}){sub 2}. - Abstract: In this study, the commercial pure magnesium was coated in different aqueous solutions of Na{sub 2}SiO{sub 3} and Na{sub 3}PO{sub 4} by the micro-arc oxidation method (MAO). Coating thickness, phase composition, surface and cross sectional morphology and corrosion resistance of coatings were analyzed by eddy current method, X-ray diffraction (XRD), scanning electron microscope (SEM) and tafel extrapolation method, respectively. The average thickness of the coatings ranged from 52 to 74 {mu}m for sodium silicate solution and from 64 to 88 {mu}m for sodium phosphate solution. The dominant phases on the coatings were detected as spinal Mg{sub 2}SiO{sub 4} (Forsterite) and MgO (Periclase) for sodium silicate solution and Mg{sub 3}(PO{sub 4}){sub 2} (Farringtonite) and MgO (Periclase) for sodium phosphate solution. SEM images reveal that the coating is composed of two layers as of a porous outer layer and a dense inner layer. The corrosion results show the coating consisting Mg{sub 2}SiO{sub 4} is more resistant to corrosion than that containing Mg{sub 3}(PO{sub 4}){sub 2}.

  12. Corrosion behaviour of hot dip zinc and zinc–aluminium coatings on ...

    Indian Academy of Sciences (India)

    A comparative investigation of hot dip Zn–25Al alloy, Zn–55Al–Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn–25Al alloy coating is several ...

  13. Corrosion and nanomechanical behaviors of plasma electrolytic oxidation coated AA7020-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, A., E-mail: arjun_venu@hotmail.com [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Srinath, J. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Rama Krishna, L. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad 500005 (India); Ramesh Narayanan, P.; Sharma, S.C.; Venkitakrishnan, P.V. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

    2016-04-13

    Alumina coating was deposited on AA7020 aluminum alloy by plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviors were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. Potentiodynamic polarization (PP) was used to evaluate the corrosion resistance of the coating and slow strain rate test (SSRT) was used for evaluating the environmental cracking resistance in 3.5% NaCl solution. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The above results were compared with similar PEO coated aluminum and magnesium alloys. Results indicated that PEO coating on AA7020 alloy significantly improved the corrosion resistance. However the environmental cracking resistance was found to be only marginal. The hardness and elastic modulus values were found to be much higher when compared to the base metal and similar PEO coated 7075 aluminum alloys. The fabricated coating also exhibited good adhesive strength with the substrate similar to other PEO coated aluminum alloys reported in the literature.

  14. The electrochemical deposition of tin-nickel alloys and the corrosion properties of the coating

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Møller, Per

    2005-01-01

    electrodeposition. The alloy has unique corrosion properties and exhibits surface passivation like stainless steel. The coating is decorative and non-allergic to the skin, can replace decorative nickel and nickel-chromium coatings in many cases and decreases the risk for allergic contact dermatitis. A number...

  15. Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique

    Directory of Open Access Journals (Sweden)

    Hathaipat Koiprasert

    2007-07-01

    Full Text Available Electric arc spraying (EAS is one of the thermal spray techniques used for restoration and to providecorrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques thatmay be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25oC. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.

  16. Evaluating protection systems against marine corrosion of aeronautic alloy Alclad 2024-T3

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2011-05-01

    Full Text Available  This paper shows how two coating systems were obtained as an alternative for protection against corrosion of al clad 2024-T3which is used in battery compartment manufacture for T-41 aircraft. Such systems consist of three types of organic resin: a first layer of P-115 polyester resin as the first coating on both systems, and a second layer of Hetron 197-3 polyester resin in the first system and vinyl-ester resin in the second one. Scanning electron microscopy (SEM was used for surface morphology analysis, showing the roughness produced by surface treatment. The coatings were electrochemically characterised by electro chemical impedance spectroscopy (EIS and Tafel polarization curves; it was found that both systems had good performance against corrosion in a marine environment and the chemical surface preparation system had a superior protective pattern for Alodine5700 + 197-3 Hetron, a 1.42x10-12mpycorrosion rate being obtained while substratum rate was 1.59x10-7 mpy. 

  17. Electrochemical investigations of magnesium in DMEM with biodegradable polycaprolactone coating as corrosion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Degner, Julia; Singer, Ferdinand [Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martenstr. 7, 91058 Erlangen (Germany); Cordero, Luis; Boccaccini, Aldo R. [Department of Materials Science, WW7-BioMat, University of Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen (Germany); Virtanen, Sannakaisa, E-mail: Virtanen@ww.uni-erlangen.de [Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martenstr. 7, 91058 Erlangen (Germany)

    2013-10-01

    Magnesium and its alloys are being increasingly investigated as biodegradable metallic implant materials. However, the high corrosion rate and accumulation of hydrogen gas upon degradation prevent the clinical application of many magnesium based materials. Applying polymer or ceramic coatings is a popular approach to improve the corrosion behaviour of magnesium and its alloys. In the current research, a biodegradable polymer film of polycaprolactone (PCL) is prepared in different concentrations by spin coating, in order to influence the corrosion behaviour of 99.9% pure magnesium. The resulting polymer coating was qualified by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and tape-test according to (ASTM D3359-09) to measure the adhesion strength of the coating on the substrate. Furthermore, coated and uncoated specimens were stored up to 30 days at 37 {sup o}C in DMEM. The corrosion behaviour was investigated by polarization curves. The PCL-films were found to be uniform and without pores, but they show a low adhesion strength on the substrate. Nevertheless, remarkable improvement of the corrosion resistance of magnesium substrate can be obtained by the polymer films, depending on the film thickness and exposition time. In summary, coating magnesium with PCL is a promising method to tailor the degradation behaviour for biomedical applications.

  18. Comparison of iron and copper doped manganese cobalt spinel oxides as protective coatings for solid oxide fuel cell interconnects

    DEFF Research Database (Denmark)

    Talic, Belma; Molin, Sebastian; Wiik, Kjell

    2017-01-01

    MnCo2O4, MnCo1.7Cu0.3O4 and MnCo1.7Fe0.3O4 are investigated as coatings for corrosion protection of metallic interconnects in solid oxide fuel cell stacks. Electrophoretic deposition is used to deposit the coatings on Crofer 22 APU alloy. All three coating materials reduce the parabolic oxidation...

  19. Characterization and corrosion behavior of phytic acid coatings, obtained by chemical conversion on magnesium substrates in physiological solution; Caracterizacion y comportamiento frente a la corrosion de recubrimientos de acido fitico, obtenidos por conversion quimica, sobre substratos de magnesio en solucion fisiologica

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Alvarado, L. A.; Lomeli, M. A.; Hernandez, L. S.; Miranda, J. M.; Narvaez, L.; Diaz, I.; Garcia-Alonso, M. C.; Escudero, M. L.

    2014-10-01

    In order to improve the corrosion resistance of biodegradable magnesium and AZ31 magnesium alloy implants, a phytic acid coating has been applied on both substrates and their protective effect against corrosion has been assessed. The morphology and the chemical nature of the conversion coating were analyzed by SEM/EDX, XRD and FTIR. The spectra showed that the conversion coating was amorphous, and it was composed of Mg, O, and P on magnesium surface, along with Al, Zn and C on AZ31 alloy. The main coating components were chelate compounds formed by phytic acid and metallic ions. The corrosion resistance of bare and coated samples was evaluated by potentiodynamic polarization technique in Hank's solution at 37 degree centigrade. The results indicate that phytic acid conversion coatings provided a very effective protection to the magnesium substrates studied. (Author)

  20. Corrosion inhibition and photoactivity behavior of N-substituted polycarbazole-coated natural pyrite electrode

    Energy Technology Data Exchange (ETDEWEB)

    Sezer, E.; Sarac, A.S.; Yavuz, O.

    1999-07-01

    Conductive films of poly (N-vinylcarbazole) (PVCz) and polycarbazole (PCz) were coated electrochemically on a natural iron sulfide (FeS{sub 2}) surface. The corrosion, photocorrosion, and photoactivity characteristics of coated electrodes were investigated in potassium iodide/iodide (Kl/I{sub 2}) redox electrolyte. However, PVCz was obtained by oxidative polymerization of N-vinylcarbazole (NVCz) by ceric ammonium nitrate (CAN) and showed photoconductivity also was deposited on the natural FeS{sub 2} surface chemically from toluene/cyclohegzanone solution, and the electrode was tested for photoactivity. Electrochemical coating inhibited corrosion and photocorrosion of FeS{sub 2} causing some decrease in photoactivity, while chemical coating of thin, transparent PVCz on the surface enhanced the photoactivity and inhibited the corrosion and photocorrosion.

  1. EFFECT OF ALUMINIUM AND MAGNESIUM ON THE CORROSION RESISTANCE OF ZINC COATINGS

    Directory of Open Access Journals (Sweden)

    Leszek Klimek

    2017-06-01

    Full Text Available This article presents the research on corrosion resistance of Zn-Al-Mg coatings with varying aluminium and magnesium content. Aluminium and magnesium were added directly to the zinc bath at 10:1 rate. There was found more than sixfold increase in corrosion resistance of zinc coatings with aluminium content at the level of 4% of weight and magnesium content at the level of 0.4% of weight. In contrast to the amounts applied in the literature, such content of these alloy additives in the zinc bath limits to a significant extent the amount of intermetallic phases in zinc coatings obtained from such baths. This, in consequence, results in high resistance to corrosion with simultaneous retention of high plasticity of these coatings.

  2. Anti-corrosive Conversion Coating on Aluminium Alloys Using High Temperature Steam

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    and heterogeneity of native oxide layer does not provide long time corrosion resistance and adhesion of organic coating for a particular function in different environments. In order to enhance the corrosion resistance and adhesion of organic coating, the aluminium native oxide layer is treated to transform...... or convert to a functional conversion coating. In the last several decades chromate conversion coating (CrCCs) have been the most common conversion coatings used for aluminium alloys. Due to the toxicity of the hexavalent chrome, however, environmental friendly alternatives to CrCCs have been investigated...... extensively. Despite the intense research no equivalent substitute for (CrCCs) has been found. For these reasons, alternative conversion coatings are sought for substituting existing ones. Aluminium alloys AA 1090, Peraluman 706, and AA 6060 were subjected to high pressure steam treatment and various...

  3. Phenolic Modified Ceramic Coating on Biodegradable Mg Alloy: The Improved Corrosion Resistance and Osteoblast-Like Cell Activity

    Directory of Open Access Journals (Sweden)

    Hung-Pang Lee

    2017-06-01

    Full Text Available Magnesium alloys have great potential for developing orthopedic implants due to their biodegradability and mechanical properties, but the rapid corrosion rate of the currently-available alloys limits their clinical applications. To increase the corrosion resistance of the substrate, a protective ceramic coating is constructed by a micro-arc oxidation (MAO process on ZK60 magnesium alloy. The porous ceramic coating is mainly composed of magnesium oxide and magnesium silicate, and the results from cell cultures show it can stimulate osteoblastic cell growth and proliferation. Moreover, gallic acid, a phenolic compound, was successfully introduced onto the MAO coating by grafting on hydrated oxide and chelating with magnesium ions. The gallic acid and rough surface of MAO altered the cell attachment behavior, making it difficult for fibroblasts to adhere to the MAO coating. The viability tests showed that gallic acid could suppress fibroblast growth and stimulate osteoblastic cell proliferation. Overall, the porous MAO coating combined with gallic acid offered a novel strategy for increasing osteocompatibility.

  4. Effects of hydroxyapatite/Zr and bioglass/Zr coatings on morphology and corrosion behaviour of Rex-734 alloy.

    Science.gov (United States)

    Say, Y; Aksakal, B

    2016-06-01

    To improve corrosion resistance of metallic implant surfaces, Rex-734 alloy was coated with two different bio-ceramics; single-Hydroxyapatite (HA), double-HA/Zirconia(Zr) and double-Bioglass (BG)/Zr by using sol-gel method. Porous surface morphologies at low crack density were obtained after coating and sintering processes. Corrosion characteristics of coatings were determined by Open circuit potential and Potentiodynamic polarization measurements during corrosion tests. Hardness and adhesion strength of coating layers were measured and their surface morphologies before and after corrosion were characterized by scanning electron microscope (SEM), XRD and EDX. Through the SEM analysis, it was observed that corrosion caused degradation and sphere-like formations appeared with dimples on the coated surfaces. The coated substrates that exhibit high crack density, the corrosion was more effective by disturbing and transmitting through the coating layer, produced CrO3 and Cr3O8 oxide formation. It was found that the addition of Zr provided an increase in adhesion strength and corrosion resistance of the coatings. However, BG/Zr coatings had lower adhesion strength than the HA/Zr coatings, but showed higher corrosion resistance.

  5. NIBSORB {sup registered}: A coating for the production of absorber elements subjected to corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Patzelt, M. [Metallveredlung GmbH und Co. KG, Solingen (Germany)

    2004-07-01

    NIBSORB {sup registered}. technology stands for an application-specific process for the production of absorber elements. An electrolytic plating process is used to incorporate the neutron poison boron carbide very homogenously and in high concentration into a thick nickel coating. Highly absorbent and corrosion-resistant coatings can be achieved in this way. Applied to base materials of any shape and size, these coatings allow absorbers to be developed which are carefully tailored to the requirements in any given case.

  6. Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

    Energy Technology Data Exchange (ETDEWEB)

    Cambon, Jean-Baptiste, E-mail: cambon@chimie.ups-tlse.fr [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France); Esteban, Julien; Ansart, Florence; Bonino, Jean-Pierre; Turq, Viviane [Institut Carnot CIRIMAT, Université de Toulouse, UMR CNRS 5085, 118 Route de Narbonne, 31062 Toulouse Cedex 9 (France); Santagneli, S.H.; Santilli, C.V.; Pulcinelli, S.H. [Departamento Fısico-Química, Instituto de Química, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil)

    2012-11-15

    Highlights: ► New sol–gel routes to replace chromates for corrosion protection of aluminum. ► Effect of cerium concentration on the microstructure of xerogel. ► Electrochemical and mechanical performances of hybrid coating with different cerium contents. ► Good correlation between the different results with an optimal cerium content of 0.01 M. -- Abstract: An organic–inorganic hybrid coating was developed to improve the corrosion resistance of the aluminum alloy AA 2024-T3. Organic and inorganic coatings derived from glycidoxypropyl-trimethoxysilane (GPTMS) and aluminum tri-sec-butoxide Al(O{sup s}Bu){sub 3}, with different cerium contents, were deposited onto aluminum by dip-coating process. Corrosion resistance and mechanical properties were investigated by electrochemical impedance measurements and nano-indentation respectively. An optimal cerium concentration of 0.01 M was evidenced. To correlate and explain the hybrid coating performances in relation to the cerium content, NMR experiments were performed. It has been shown that when the cerium concentration in the hybrid is higher than 0.01 M there are important modifications in the hybrid structure that account for the mechanical properties and anti-corrosion behavior of the sol–gel coating.

  7. Electrochemical corrosion behaviour of Mg-Al alloys with thermal spray Al/SiCp composite coatings; Comportamiento a la corrosion electroquimica de aleaciones MgAl con recubrimientos de materiales compuestos Al/SiCp mediante proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Feliu Jr, S.; Merino, M. C.; Mohedano, M.; Casajus, P.; Arrabal, R.

    2010-07-01

    The corrosion protection of Mg-Al alloys by flame thermal spraying of Al/SiCp composite coatings was evaluated by electrochemical impedance spectroscopy in 3.5 wt.% NaCl solution. The volume fraction of SiC particles (SiCp) varied between 5 and 30%. The as-sprayed Al/SiCp composite coatings revealed a high number of micro-channels, largely in the vicinity of the SiC particles, that facilitated the penetration of the electrolyte and the subsequent galvanic corrosion of the magnesium substrates. The application of a cold-pressing post-treatment reduced the degree of porosity of the coatings and improved the bonding at the coating/substrate and Al/SiC interfaces. This resulted in improved corrosion resistance of the coated specimens. The effectiveness of the coatings slightly decreased with the addition of 5-30 vol.% SiCp compared with the un reinforced thermal spray aluminium coatings. (Author) 31 refs.

  8. Microstructure and Corrosion Behavior of Ni-Alloy/CrN Nanolayered Coatings

    Directory of Open Access Journals (Sweden)

    Hao-Hsiang Huang

    2011-01-01

    Full Text Available The Ni-alloy/CrN nanolayered coatings, Ni-Al/CrN and Ni-P/CrN, were deposited on (100 silicon wafer and AISI 420 stainless steel substrates by dual-gun sputtering technique. The influences of the layer microstructure on corrosion behavior of the nanolayered thin films were investigated. The bilayer thickness was controlled approximately 10 nm with a total coating thickness of 1m. The single-layer Ni-alloy and CrN coatings deposited at 350∘C were also evaluated for comparison. Through phase identification, phases of Ni-P and Ni-Al compounds were observed in the single Ni-alloy layers. On the other hand, the nanolayered Ni-P/CrN and Ni-Al/CrN coatings showed an amorphous/nanocrystalline microstructure. The precipitation of Ni-Al and Ni-P intermetallic compounds was suppressed by the nanolayered configuration of Ni-alloy/CrN coatings. Through Tafel analysis, the corr and corr values ranged from –0.64 to –0.33 V and 1.42×10−5 to 1.14×10−6 A/cm2, respectively, were deduced for various coating assemblies. The corrosion mechanisms and related behaviors of the coatings were compared. The coatings with a nanolayered Ni-alloy/CrN configuration exhibited a superior corrosion resistance to single-layer alloy or nitride coatings.

  9. 46 CFR 120.210 - Protection from wet and corrosive environments.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Protection from wet and corrosive environments. 120.210... INSTALLATION General Requirements § 120.210 Protection from wet and corrosive environments. (a) Electrical... environments must be of suitable construction and corrosion-resistant. ...

  10. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann

    2015-01-01

    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...... with Ni seed layer coated by a multi-layered graphene thin film (G/Ni/SS). The graphene film, synthesized by chemical vapour deposition (CVD), has a moderate amount of defects according to Raman spectroscopy. Short/medium-term corrosion test shows no significant advantage of using G/Ni/SS rather than Ni....../SS, both samples exhibiting a similar trend, thus questioning the short-term positive effect of graphene coatings. However, partial immersion in boiling seawater for three weeks reveals a clear superiority of the graphene coating with respect to steel just protected by Ni. After the test, the graphene film...

  11. Foamed glass insulating block ends costly baghouse corrosion and protects new steel stack

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    A secondary smelter company on the West Coast, that reclaims certain metals from scrap products such as wet cell batteries, was spending hundreds of thousands of dollars each year to replace corroded metal in the baghouses at one of its installations. Various types of protective coatings and special steels had been tried, but the maximum life of each unit was about a year due to condensation of flue gas corrosives on the inside surface of the metal walls. In 1979, at one of its sites, the company decided to test an acid/corrosion protection system specifically designed for stack, duct, and breeching installations and related equipment. The system consists of totally inorganic formed borosilicate glass block that can handle temperatures to 960/sup 0/F and is resistant to atttack by most acids and corrosives except fluorides and strong alkalis. The closed-cell structure provides a strong, lightweight product that reduces installation costs, and has extremely low thermal conductivity for an efficient heat barrier. The 12 X 18'' block is directly bonded to a clean metal surface by an 1/8'' thick layer of urethane asphalt that forms a virtually impervious flexible membrane to further protect the metal from corrosive attack. The flexible bond also absorbs expansion and contraction due to thermal changes, and reduces the probability of cracked blocks and dropoff. The protection provided by the foamed glass block and adhesive membrane system has eliminated the very expensive annual replacement of corroded baghouse walls. The performance of the lining system in the baghouses was so successful that the smelter decided to use it in a new metal stack that is 165' high.

  12. Graphene Coatings: Probing the Limits of the One Atom Thick Protection Layer

    DEFF Research Database (Denmark)

    Nilsson, Louis; Andersen, Mie; Balog, Richard

    2012-01-01

    The limitations of graphene as an effective corrosion-inhibiting coating on metal surfaces, here exemplified by the hex-reconstructed Pt(100) surface, are probed by scanning tunneling microscopy measurements and density functional theory calculations. While exposure of small molecules directly onto...... the Pt(100) surface will lift the reconstruction, a single graphene layer is observed to act as an effective coating, protecting the reactive surface from O2 exposure and thus preserving the reconstruction underneath the graphene layer in O2 pressures as high as 104 mbar. A similar protective effect...

  13. Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers for Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Michael D. Blanton

    2012-09-01

    Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

  14. Investigation of the cut-edge corrosion of organically-coated galvanized steel after accelerated atmospheric corrosion test

    Directory of Open Access Journals (Sweden)

    Reşit Yıldız

    2015-11-01

    Full Text Available The cut edge corrosion of organically coated (epoxy, polyurethane and polyester galvanized steel was investigated using electrochemical impedance spectroscopy (EIS. Measurements were performed on specimens that had been tested in an accelerated atmospheric corrosion test. The samples were subjected to 10 s fogging and 1 h awaiting cycles in an exposure cabinet (120 and 180 days with artificial acid rain solution. According to the investigation, the coatings were damaged from the cut edge into the sheet, this distance was about 0.8 cm. These defects were more pronounced at after 180 days in proportion to after 120 days.

  15. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II : Properties of Steel Surface Layers

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

  16. The variation of corrosion potential with time for coated metal surfaces

    Science.gov (United States)

    Danford, M. D.; Knockemus, W. W.

    1986-01-01

    The variation of corrosion potential (EsubCORR) with time has been measured for 4130 steel coated with a preservative compound and for primer coated 2219-T87 aluminum. The data for coated steel samples show a great deal of scatter, and a smoothing procedure has been developed to enable proper interpretation of the data. The EsubCORR-time curves for coated steel exhibit a maximum, in agreement with the results of previous studies, where the data were the average of those for a large number of samples, while the present data were obtained from a single sample. In contrast, the EsubCORR-time curves for primer coated 2219-T87 aluminum samples show no significant variations, although considerable activity is indicated by the resistance-time and corrosion rate-time curves.

  17. Investigation on the corrosion behavior of physical vapor deposition coated high speed steel

    Directory of Open Access Journals (Sweden)

    R Ravi Raja Malarvannan

    2015-08-01

    Full Text Available This work emphasizes on the influence of the TiN and AlCrN coatings fabricated on high speed steel form tool using physical vapor deposition technique. The surface microstructure of the coatings was studied using scanning electron microscope. Hardness and corrosion studies were also performed using Vickers hardness test and salt spray testing, respectively. The salt spray test results suggested that the bilayer coated (TiN- bottom layer and AlCrN- top layer substrate has undergone less amount of corrosion, and this is attributed to the dense microstructure. In addition to the above, the influence of the above coatings on the machining performance of the high speed steel was also evaluated and compared with that of the uncoated material and the results suggested that the bilayered coating has undergone very low weight loss when compared with that of the uncoated substrate depicting enhanced wear resistance.

  18. COMPARATIVE STUDY OF THE CORROSION BEHAVIOR OF HOT DIP GALVANIZED, GALVANNEAL AND GALVALUME COATED STEELS

    Directory of Open Access Journals (Sweden)

    Álvaro Pritzel dos Santos

    2013-10-01

    Full Text Available Corrosion attack of Hot Dip Zn coatings on steels is comparatively studied. For this, the electrochemical behavior of the coatings hot dip galvanized (GI, galvanneal (GA and galvalume (Zn55Al are analyzed in chloride solutions by cyclic voltammetry and by Scanning Vibrating Electrode Technique, with and without the incidence of white light. Coatings were characterized by Scanning Electronic Microscopy and Energy Dispersive X-Ray Spectrometry. The results show that the incidence of white UV-VIS light has a minor influence on the corrosive process, although the coatings contain intermetallic phases with semiconductor nature. The tests show that among the three coatings, GA has the slowest dissolution rate, when in contact with the steel for high exposed areas of steel.

  19. Corrosion and wettability of PEO coatings on magnesium by addition of potassium stearate

    Directory of Open Access Journals (Sweden)

    S.S. Farhadi

    2017-06-01

    Full Text Available Hydrophobic PEO coatings were fabricated in an electrolyte containing potassium stearate. The wetting behaviour of coated samples was studied using dynamic and static contact angle. Also, the corrosion behaviour of the samples was evaluated by polarization method. The dynamic contact angle and hysteresis of the contact angle for PEO coating were evaluated by Wilhelmy plate method. There was an increase in the contact angle of the nanocomposite and traditional PEO coatings when potassium stearate was added to the electrolyte up to 130°. The more hydrophobic coatings, showed more corrosion resistance in 3.5 wt.% NaCl solution. The synergistic effect of potassium stearate and nanoparticles increased the hydrophobicity because of assembling of fatty acid on ceramic powder.

  20. Augmenting MFL Tools with Sensors That Assess Coating Condition

    Science.gov (United States)

    2009-03-16

    External coatings are routinely used to protect transmission pipelines from corrosion; however, coatings may degrade or disbond over time enabling corrosion to occur. Transmission pipeline operators often use magnetic flux leakage (MFL) in-line inspe...

  1. Intelligent saline enabled self-healing of multilayer coatings and its optimization to achieve redox catalytically provoked anti-corrosion ability

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Junaid Ali; Tang, Shaochun; Meng, Xiangkang, E-mail: mengxk@nju.edu.cn

    2016-10-15

    Highlights: • Multilayer coatings were prepared with good self-healing and anti-corrosion ability. • The lifespan of SS is much improved and it is stable even after 120 h in 3.5% NaCl. • Multilayer structure with redox catalytic and self-healing ability leads to high P{sub e}. • Saline-triggered self-healing and anti-corrosion mechanisms were envisaged. - Abstract: To obtain a coating with both self-healing and redox catalytic ability to protect a metal substrate from corrosion under aggressive environment is strongly desired. Herein, we report the design and fabrication of intelligent polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) multilayer composite coatings by spin assembly. The main influencing factors, including solution concentration (c) and disk rotating speed (ω) were studied in order to gain excellent performance. The resulting multilayer coatings with thickness in a range from 0.47 to 2.94 μm can heal severe structural damages and sustain a superior anti-corrosive performance for 120 h in 3.5% NaCl. The PANI-PAA layer enhances the anti-corrosion property and PEI layer contributes to the self-healing ability as well as their multilayer combination strengthens them. The improved self-healing ability is attributed to the rearrangement and reversible non-covalent interactions of the PANI-PAA and PEI layers that facilitates electrostatic repairing.

  2. Advanced materials and protective coatings in aero-engines application

    OpenAIRE

    M. Hetmańczyk; L. Swadźba; B. Mendala

    2007-01-01

    Purpose: The following article demonstrates the characteristics of the materials applied as parts of aircraft engine turbines and the stationary gas turbines. The principal technologies for manufacturing the heat resistant coatings and the erosion and corrosion resistant coatings were characterized. Sample applications for the aforementioned coatings are presented: on turbine blades, compressor blades and on parts of combustion chambers of aircraft engines.Design/methodology/approach: The nic...

  3. Design and characterization of non-toxic nano-hybrid coatings for corrosion and fouling resistance

    Directory of Open Access Journals (Sweden)

    P. Saravanan

    2016-09-01

    Full Text Available Epoxy resin modified with nano scale fillers offers excellent combination of properties such as enhanced dimensional stability, mechanical and electrical properties, which make them ideally suitable for a wide range of applications. However, the studies about functionalized nano-hybrid for coating applications still require better insight. In the present work we have developed silane treated nanoparticles and to reinforce it with diglycidyl epoxy resin to fabricate surface functionalized nano-hybrid epoxy coatings. The effect of inorganic nano particles on the corrosion and fouling resistance properties was studied by various (1, 3, 5 and 7 wt% filler loading concentrations. Diglycidyl epoxy resin (DGEBA commonly was used for coating. 3-Aminopropyltriethoxysilane (APTES was used as a coupling agent to surface treats the TiO2 nanoparticles. The corrosion and fouling resistant properties of these coatings were evaluated by electrochemical impedance and static immersion tests, respectively. Nano-hybrid coating (3 wt% of APTES–TiO2 showed corrosion resistance up to 108 Ω cm2 after 30 days immersion in 3.5% NaCl solution indicating an excellent corrosion resistance. Static immersion test was carried out in Bay of Bengal (Muttukadu which has reflected good antifouling efficiency of the 3 wt% APTES–TiO2 loaded nano-hybrid coating up to 6 months.

  4. A silanol-based nanocomposite coating for protection of AA-2024 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.; Pavez, J.; Azocar, I.; Zagal, J.H. [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile); Zhou, X. [Corrosion and Protection Centre, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Melo, F. [Departamento de Fisica, Facultad de Ciencias, Universidad de Santiago de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Santiago (Chile); Thompson, G.E. [Corrosion and Protection Centre, School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Paez, M.A., E-mail: maritza.paez@usach.cl [Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Avenida Bernardo O' Higgins 3363, Casilla 40, Correo 33, Santiago (Chile)

    2011-09-01

    Highlights: {center_dot} A new silanol-based hybrid coating has been synthesized. {center_dot} The incorporation of CeO{sub 2} and ZrO{sub 2} nanoparticles into the coating greatly improves the corrosion resistance of the coated aluminium alloy. {center_dot} The effectiveness of the coating is increasingly evident for long term exposure to the sodium chloride solution. {center_dot} The silanol-based nanocomposite coatings have self-healing ability. - Abstract: A new hybrid sol-gel type film, composed of tetraethylorthosilicate (TEOS) and tetraocthylorthosilicate (TEOCS), and modified with different nanoparticle systems, has been investigated as a coating for protection of AA-2024-T3 aluminium alloy. The nanoparticle systems considered were either ZrO{sub 2} or CeO{sub 2} or their combination{sub .} The zirconia nanoparticles were prepared from a Zr (IV) propoxide sol (TPOZ), using an organic stabilizer, and the CeO{sub 2} nanoparticles were developed spontaneously after adding cerium nitrate solution to the hybrid sol. The chemical composition and the structure of the hybrid sol-gel films were examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The corrosion resistance of the coated AA-2024 alloy was examined by potentiodynamic polarization. The results revealed that, for short exposure times in the electrolyte, incorporation of ZrO{sub 2} or CeO{sub 2} nanoparticles in the hybrid film does not provide an increase in the corrosion resistance of the coated AA-2024 alloy. Further, the resistance was significantly reduced by increasing the nanoparticle content. Conversely, by incorporating both nanoparticles (ZrO{sub 2} and CeO{sub 2}), the corrosion resistance of the resulting hybrid films increased slightly. The behavior changed significantly when the coated alloy was exposed to the electrolyte for 5 days. The corrosion resistance of the coatings, unmodified and modified with CeO{sub 2} or Zr

  5. Corrosion resistance of PANi-coated steel in simulated PEMFC anodic environment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Naibao; Liang, Chenghao [Electromechanics and Materials Engineering College, Dalian Maritime University, Dalian 116026 (China); Yi, Baolian [Fuel Cell R and D Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2008-01-15

    By using electrochemical techniques, the corrosion resistance of polyaniline (PANi)-coated 1Cr18Ni9Ti stainless steel was investigated in simulated proton exchange membrane fuel cell (PEMFC) anodic environment. The results indicated that the compact conductive PANi film could be obtained on 1Cr18Ni9Ti steel by pulse potentiostatic method (PPSM). When steel was coated with conductive PANi, its corrosion potential was improved from -350 to 250 mV in simulated corrosion solution. During the potentiostatic polarization in PEMFC's anodic operation environment, the film is stable and there is no degradation of the PANi film. The film has no effect on the performance of the fuel cell. Further effort to improve the performance of conductive polymer coatings and to estimate the long-term performance in actual PEMFC environment is desirable. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  6. Corrosion protection pays off for coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, T.

    2006-11-15

    Zinc has long been used to hot-dip galvanise steel to deliver protection in harsh environments. Powder River Basin or eastern coal-fired plants benefit from using galvanized steel for conveyors, vibratory feeders, coal hoppers, chutes, etc. because maintenance costs are essentially eliminated. When life cycle costs for this process are compared to an alternative three-coal paint system for corrosion protection, the latter costs 5-10 times more than hot-dip galvanizing. An AEP Power Plant in San Juan, Puerto Rico and the McDuffie Coal Terminal in Mobile, AL, USA have both used hot-dip galvanized steel. 1 fig., 1 tab.

  7. Corrosion Protection of Copper Using Al2O3, TiO2, ZnO, HfO2, and ZrO2Atomic Layer Deposition.

    Science.gov (United States)

    Daubert, James S; Hill, Grant T; Gotsch, Hannah N; Gremaud, Antoine P; Ovental, Jennifer S; Williams, Philip S; Oldham, Christopher J; Parsons, Gregory N

    2017-02-01

    Atomic layer deposition (ALD) is a viable means to add corrosion protection to copper metal. Ultrathin films of Al 2 O 3 , TiO 2 , ZnO, HfO 2 , and ZrO 2 were deposited on copper metal using ALD, and their corrosion protection properties were measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). Analysis of ∼50 nm thick films of each metal oxide demonstrated low electrochemical porosity and provided enhanced corrosion protection from aqueous NaCl solution. The surface pretreatment and roughness was found to affect the extent of the corrosion protection. Films of Al 2 O 3 or HfO 2 provided the highest level of initial corrosion protection, but films of HfO 2 exhibited the best coating quality after extended exposure. This is the first reported instance of using ultrathin films of HfO 2 or ZrO 2 produced with ALD for corrosion protection, and both are promising materials for corrosion protection.

  8. Effects of sintering temperature on the corrosion behavior of AZ31 alloy with Ca–P sol–gel coating

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Bo [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Shi, Ping, E-mail: p_shi@sohu.com [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); Wei, Donghua [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China); E, Shanshan [School of Mathematics and Physics, Bohai University, Jinzhou, Liaoning Province, 121013 (China); Li, Qiang; Chen, Yang [School of Materials Science and Engineering, Liaoning University of Technology, Jinzhou, Liaoning Province, 121001 (China)

    2016-04-25

    To slow down the initial biodegradation rate of magnesium alloy, calcium phosphate (Ca–P) coatings were prepared on AZ31 magnesium alloy by a sol–gel technique. To study the effects of sintering temperature on microstructure, bonding strength and corrosion behavior of the coatings, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and an adhesive strength test were used to characterize the coatings. The corrosion resistance of the coatings was investigated by immersion test and electrochemical corrosion techniques in simulated body fluid (SBF) solution. It shows that the sol–gel coatings consist of Ca{sub 2}P{sub 2}O{sub 7}, mixture of Ca{sub 2}P{sub 2}O{sub 7}, Ca{sub 3}(PO{sub 4}){sub 2} and hydroxyapatite, and hydroxyapatite, by sintering respectively at 300 °C, 400 °C and 500 °C. There are major cracks on the coatings. The crack area portion on the coating and the bonding strength at the interface between the calcium phosphate coating and the bare AZ31 increases, and the corrosion resistance of the coated AZ31 in SBF decreases with increasing sintering temperatures from 300 °C to 500 °C. Based on our investigations, the corrosion resistance of the coated AZ31 in SBF depends mainly on the crack area portion on the coatings, rather than on the coating phase stability. - Highlights: • Ca–P coating was prepared on AZ31 alloy by a sol–gel technique. • Crack area portion in the coating increases with temperatures. • Bonding strength between Ca–P coating and substrate increases with temperatures. • Corrosion resistance of the coated AZ31 in SBF decreases with temperatures. • Corrosion resistance of the coated AZ31 depends mainly on the crack area portion.

  9. Electrochemical synthesis and characterisation of hybrid materials polypyrrole/dodecatungstophosphate as protective agents against steel corrosion

    Science.gov (United States)

    Bonastre Cano, Jose Antonio

    hand, this pretreatment should guarantee appropriate conditions in order to obtain a coating with high adhesion on carbon steel. Once studied the better parameters for the synthesis of the hybrid material by cyclic voltammetry, hybrid material is morphological, chemical and electrochemical characterised by the following techniques: Cyclic Voltammetry, Scanning Electron Microscopy, Energy Dispersive X Ray, X Ray Photoelectron Spectroscopy and Electrochemical Impedance Spectroscopy. The hybrid material polypyrrole/PW 12O403-. chemical structure presents Fe oxides and hydroxide within the polypyrrole polycationic matrix. Hybrid material polypyrrol/PW12O403- diminishes the corrosion of carbon steel in NaOH and Porland cement filtering solutions. These cement solutions simulate the pore fluid conditions existing in cured mortar or concrete elements. Fe ion concentration data were determinated in corrosion tests. Voltammetric response of polymeric coatings was evaluated by cyclic voltammetry. Finally, the protection provided by hybrid material polypyrrole/PW 12O403, in oxidised and reduced state, was evaluated on carbon steel electrodes embedded in Portland cement mortars immersed in seawater and submitted to an accelerated carbonation process for 265 days. Polymeric material covered carbon steel electrodes in reduced state suffer a Fe gravimetric loss 15 times lower than the ones of bare electrodes against chlorides attack, due to the effect of physical barrier. Hybrid material covered electrodes in oxidised state after being submitted to a carbonation process suffer a Fe gravimetric loss 2.5 times lower than the ones of bare electrodes, due to galvanic protection provided by hybrid material polypyrrole/PW 12O403- on carbon steel.

  10. Corrosion resistance of Cu-Al coatings produced by thermal spray

    Directory of Open Access Journals (Sweden)

    Laura Marcela Dimaté Castellanos

    2012-01-01

    Full Text Available Many components in the shipbuilding industry are made of copper-based alloys. These pieces tend to break due to corrosion generated by a marine environment; such components can be salvaged through surface engineering, through deposition of suitable coatings. This paper studied the influence of three surface preparation methods involving phosphor bronze substrates concerning the corrosion resistance of commercial coatings having Al-Cu +11% Fe chemical composition. The surface was prepared using three methods: sand blasting, shot blasting and metal polishing with an abrasive disk (with and without a base layer. The deposited coatings were micro-structurally characterised by x-ray diffraction (XRD, optical microscopy and scanning electron microscopy (SEM. Corrosion resistance was evaluated by electrochemical test electrochemical impedance spectroscopy (EIS. Surfaces prepared by sandblasting showed the best resistance to corrosion, so these systems could be a viable alternative for salvaging certain parts in the marine industry. The corrosion mechanisms for the coatings produced are discussed in this research.

  11. A sturdy self-cleaning and anti-corrosion superhydrophobic coating assembled by amino silicon oil modifying potassium titanate whisker-silica particles

    Science.gov (United States)

    Lv, Chongjiang; Wang, Huaiyuan; Liu, Zhanjian; Zhang, Wenbo; Wang, Chijia; Tao, Ruifeng; Li, Meiling; Zhu, Yanji

    2018-03-01

    A sturdy self-cleaning and anticorrosion superhydrophobic coating based on poly(phenylene sulfide) (PPS) matrix has been successfully fabricated by combination of sol-gel and spraying technology without using any fluorine materials. The prepared coating possessed excellent superhydrophobicity with the water contact angle (WCA) (161 ± 1.2)° and slide angle (SA) (2 ± 1.5)°, which was ascribed to the synergistic effect of low-surface energy material amino silicon oil (ASO) and the binary potassium titanate whisker-silica (PTW-SiO2) composite particles formed by in-situ growth of SiO2 on modified PTW via sol-gel. Moreover, The PPS/ASO/PTW-SiO2 superhydrophobic coating exhibited decent self-cleaning property with clean surface even after 100 times immersion in muddy solution. The abrasion test demonstrated that the mechanical stability of prepared coating was about 2 times of the pure PPS coating. Simultaneously, the potentiodynamic polarization and electrochemical impedance spectroscopy testified the excellent corrosion resistance of prepared coating with the performance of lower corrosion current (1.289 × 10-10 A/cm2) and high protection efficiency (99.999%) even after immersion in 3.5 wt.% NaCl solution for 28 days. It is believed that this sturdy self-cleaning and anti-corrosion superhydrophobic coating might have a promising application prospect in industry.

  12. Nanocomposite protective coatings for battery anodes

    Science.gov (United States)

    Lemmon, John P; Xiao, Jie; Liu, Jun

    2014-01-21

    Modified surfaces on metal anodes for batteries can help resist formation of malfunction-inducing surface defects. The modification can include application of a protective nanocomposite coating that can inhibit formation of surface defects. such as dendrites, on the anode during charge/discharge cycles. For example, for anodes having a metal (M'), the protective coating can be characterized by products of chemical or electrochemical dissociation of a nanocomposite containing a polymer and an exfoliated compound (M.sub.a'M.sub.b''X.sub.c). The metal, M', comprises Li, Na, or Zn. The exfoliated compound comprises M' among lamella of M.sub.b''X.sub.c, wherein M'' is Fe, Mo, Ta, W, or V, and X is S, O, or Se.

  13. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    or inhibitor. Comparable metallic alloys such as SAM2X5 and SAM1651 may also experience crevice corrosion under sufficiently harsh conditions. Accelerated crevice corrosion tests are now being conducted to intentionally induce crevice corrosion, and to determine those environmental conditions where such localized attack occurs. Such materials are extremely hard, and provide enhanced resistance to abrasion and gouges (stress risers) from backfill operations, and possibly even tunnel boring. The hardness of Type 316L Stainless Steel is approximately 150 VHN, that of Alloy C-22 is approximately 250 VHN, and that of HVOF SAM2X5 ranges from 1100-1300 VHN. These new materials provide a viable coating option for repository engineers. SAM2X5 and SAM1651 coatings can be applied with thermal spray processes without any significant loss of corrosion resistance. Both Alloy C-22 and Type 316L stainless lose their resistance to corrosion during thermal spraying. Containers for the transportation, storage and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) with corrosion resistant coatings are envisioned. For example, an enhanced multi-purpose container (MPC) could be made with such coatings, leveraging existing experience in the fabrication of such containers. These coating materials could be used to protect the final closure weld on SNF/HLW disposal containers, eliminate need for stress mitigation. Integral drip shield could be produced by directly spraying it onto the disposal container, thereby eliminating the need for an expensive titanium drip shield. In specific areas where crevice corrosion is anticipated, such as the contact point between the disposal container and pallet, HVOF coatings could be used to buildup thickness, thereby selectively adding corrosion life where it is needed. Both SAM2X5 & SAM1651 have high boron content which enable them to absorb neutrons and therefore be used for criticality control in baskets. Alloy C-22 and 316L have

  14. Elevated Temperature Corrosion Studies of AlCrN and TiAlN Coatings by PAPVD on T91 Boiler Steel

    Science.gov (United States)

    Goyal, Lucky; Chawla, Vikas; Hundal, Jasbir Singh

    2017-11-01

    The present investigation discusses the hot corrosion behavior of AlCrN and TiAlN nano-coatings on T91 boiler steel by PAPVD process subjected to molten salt of Na2SO4-60%V2O5 at 900 °C for 50 cycles. Surface and cross-sectional studies were performed by AFM, SEM/EDS and XRD techniques to understand the corrosion kinetics and mechanism. T91 bare boiler steel as well as TiAlN-coated specimen has shown higher internal oxidation as well as weight gain. The better corrosion resistance of AlCrN-coated specimen has been observed by virtue of higher availability of Cr and Al in the oxide scale as well as adherent and dense coating. The betterment of AlCrN coating can be attributed to low internal oxidation as well as movement of Cr and Al toward oxide scale to form protective corrosion barriers.

  15. Corrosion Resistance of 304L SS Spray Coated with Zirconia Nanoparticles

    Science.gov (United States)

    Maheswari, A. Uma; Sivakumar, M.; Indhumathi, N.; Mohan, Sreedevi R.

    2016-09-01

    Influence of substrate temperature on corrosion (in 3.5% NaCl) and wear resistance of nanostructured zirconia thin film coated 304L SS substrates are studied by electrochemical and nano-indentation methods. This analysis shows 304L SS substrate spray coated with nanostructured zirconia at substrate temperature closer to the boiling point of the spray solvent ethanol exhibited good corrosion and wear resistance behaviour. This is because of the compressive stress developed during film fabrication at lower substrate temperature (∼50 °C) and hence constrains the indentation plasticity, which leads to higher indentation load than the bare 304L SS.

  16. Environmental Friendly Coatings & Corrosion Prevention for Flight Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Kennedy Space Center (KSC) has undertaken a study to find environmentally friendly alternatives for the petroleum and solvent-based corrosion-preventive compounds...

  17. Sprayable Phase Change Coating Thermal Protection Material

    Science.gov (United States)

    Richardson, Rod W.; Hayes, Paul W.; Kaul, Raj

    2005-01-01

    NASA has expressed a need for reusable, environmentally friendly, phase change coating that is capable of withstanding the heat loads that have historically required an ablative thermal insulation. The Space Shuttle Program currently relies on ablative materials for thermal protection. The problem with an ablative insulation is that, by design, the material ablates away, in fulfilling its function of cooling the underlying substrate, thus preventing the insulation from being reused from flight to flight. The present generation of environmentally friendly, sprayable, ablative thermal insulation (MCC-l); currently use on the Space Shuttle SRBs, is very close to being a reusable insulation system. In actual flight conditions, as confirmed by the post-flight inspections of the SRBs, very little of the material ablates. Multi-flight thermal insulation use has not been qualified for the Space Shuttle. The gap that would have to be overcome in order to implement a reusable Phase Change Coating (PCC) is not unmanageable. PCC could be applied robotically with a spray process utilizing phase change material as filler to yield material of even higher strength and reliability as compared to MCC-1. The PCC filled coatings have also demonstrated potential as cryogenic thermal coatings. In experimental thermal tests, a thin application of PCC has provided the same thermal protection as a much thicker and heavier application of a traditional ablative thermal insulation. In addition, tests have shown that the structural integrity of the coating has been maintained and phase change performance after several aero-thermal cycles was not affected. Experimental tests have also shown that, unlike traditional ablative thermal insulations, PCC would not require an environmental seal coat, which has historically been required to prevent moisture absorption by the thermal insulation, prevent environmental degradation, and to improve the optical and aerodynamic properties. In order to reduce

  18. Corrosion resistance and development length of steel reinforcement with cementitious coatings

    Science.gov (United States)

    Pei, Xiaofei

    This research program focused on the corrosion resistance and development length of reinforcing steel coated with Cementitious Capillary Crystalline Waterproofing (CCCW) materials. The first part of this research program involved using the half-cell potential method to evaluate the corrosion resistance of CCCW coating materials. One hundred and two steel bars were embedded in concrete cylinders and monitored. In total, 64 steel reinforcing bars were coated with CCCW prior to embedment, 16 mortar cylinders were externally coated with CCCW, and 22 control (uncoated) samples were tested. All the samples were immersed in a 3.5% concentration chloride solution for a period of one year. Three coating types were studied: CCCW-B, CCCW-B+ C and CCCW-C+D. The test results showed that the CCCW coating materials delayed the corrosion activity to varying degrees. In particular, CCCW-C+D applied on the reinforcing steel surface dramatically delayed the corrosion activity when compared to the control samples. After being exposed to the chloride solution for a period of one year, no sign of corrosion was observed for the cylinders where the concrete surface was coated. The second part of this research evaluated the bond strength and development length of reinforcing steel coated with two types of CCCW coating materials (CCCW-B+C and CCCW-C+D) using a modified pull-out test method. A self-reacting inverted T-shaped beam was designed to avoid compression in the concrete surrounding the reinforcing steel. Steel reinforcing bars were embedded along the web portion of the T-beam with various embedded lengths and were staggered side by side. In total, six T-beams were fabricated and each beam contained 8 samples. Both short-term (7 days) and long-term (3 months) effects of water curing were evaluated. The reinforcing steel bars coated with CCCW-B+C demonstrated a higher bond strength than did samples coated with CCCW-C+D. However, the bond strengths of samples with coating materials

  19. Corrosion inhibition with different protective layers in tinplate cans for food preservation.

    Science.gov (United States)

    Grassino, Antonela Ninčević; Grabarić, Zorana; Pezzani, Aldo; Squitieri, Giuseppe; Berković, Katarina

    2010-11-01

    In this work the influence of essential onion oil (EOO) on the protection of tinplates was compared with dioctyl sebacate oil (DOS) and epoxy phenolic lacquers, which are frequently used in the food canning industry. When EOO as the protective layer instead of DOS oil was used, tinplate porosity, measured electrochemically (7.58 ± 1.97 µA cm(-2) and 23.0 ± 1.3 µA cm(-2), respectively), and iron coating mass, calculated from AAS data (1.52 ± 0.15 mg m(-2) and 3.14 ± 0.42, respectively), was much lower indicating better corrosion protection. At higher storing temperature (36 °C) the addition of EOO to canned tomato purée enhanced the formation of hydrogen with time. The increasing volume fraction of H(2) (from 34.0 to 90.9% for cans without nitrates, and from 33.8 to 89.2% for cans with nitrates) is an indicator that corrosion takes place. As the use of EOO improves the protection of tinplate compared with DOS oil, and is almost as effective as epoxy phenolic lacquer, the addition of EOO can be recommended due to lower cost of canned food production and enhanced organoleptic properties, but the storage temperature has to be lower then 36 °C. 2010 Society of Chemical Industry

  20. Multilayer Protective Coatings for High-Level Nuclear Waste Storage Containers

    Science.gov (United States)

    Fusco, Michael

    Corrosion-based failures of high-level nuclear waste (HLW) storage containers are potentially hazardous due to a possible release of radionuclides through cracks in the canister due to corrosion, especially for above-ground storage (i.e. dry casks). Protective coatings have been proposed to combat these premature failures, which include stress-corrosion cracking and hydrogen-diffusion cracking, among others. The coatings are to be deposited in multiple thin layers as thin films on the outer surface of the stainless steel waste basket canister. Coating materials include: TiN, ZrO2, TiO2, Al 2O3, and MoS2, which together may provide increased resistances to corrosion and mechanical wear, as well as act as a barrier to hydrogen diffusion. The focus of this research is on the corrosion resistance and characterization of single layer coatings to determine the possible benefit from the use of the proposed coating materials. Experimental methods involve electrochemical polarization, both DC and AC techniques, and corrosion in circulating salt brines of varying pH. DC polarization allows for estimation of corrosion rates, passivation behavior, and a qualitative survey of localized corrosion, whereas AC electrochemistry has the benefit of revealing information about kinetics and interfacial reactions that is not obtainable using DC techniques. Circulation in salt brines for nearly 150 days revealed sustained adhesion of the coatings and minimal weight change of the steel samples. One-inch diameter steel coupons composed of stainless steel types 304 and 316 and A36 low alloy carbon steel were coated with single layers using magnetron sputtering with compound targets in an inert argon atmosphere. This resulted in very thin films for the metal-oxides based on low sputter rates. DC polarization showed that corrosion rates were very similar between bare and coated stainless steel samples, whereas a statistically significant decrease in uniform corrosion was measured on coated

  1. Preparation, antibacterial effects and corrosion resistant of porous Cu–TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Haibo; Zhang, Xiangyu, E-mail: zhangxiangyu@tyut.edu.cn; Geng, Zhenhua; Yin, Yan; Hang, Ruiqiang; Huang, Xiaobo; Yao, Xiaohong; Tang, Bin

    2014-07-01

    Antibacterial TiO{sub 2} coatings with different concentrations of Cu (Cu–TiO{sub 2}) were prepared by micro-arc oxidation (MAO) on pre-sputtered CuTi films. The effect of Cu concentrations in CuTi films on the MAO process was investigated. The Cu–TiO{sub 2} coatings were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The corrosion resistance of Cu–TiO{sub 2} coatings was evaluated via potentiodynamic polarization method. The antibacterial properties were assessed by two methods: spread plate method and fluorescence staining. The experimental results demonstrate that the coatings are porous and consist of anatase phase, rutile phase and unoxidized titanium. The CuTi films are almost completely oxidized and the thickness of all MAO coatings is about 5–10 μm. Cu mainly exists as CuO in the TiO{sub 2} coatings. The Cu–TiO{sub 2} coatings exhibit excellent antibacterial activities, and the antibacterial rate gradually rise with the increase in Cu concentration in the MAO coatings. The corrosion resistance of MAO coatings is also improved slightly.

  2. Preparation and testing of corrosion and spallation-resistant coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, John P. [Univ. of North Dakota, Grand Forks, ND (United States); Cavalli, Matthew N. [Univ. of North Dakota, Grand Forks, ND (United States)

    2016-06-30

    The goal of this project was to take a recently developed method of bonding oxide dispersion-strengthened (ODS) FeCrAl plating to nickel superalloys closer to commercial use in syngas-fired turbines. The project was designed to better understand and develop the bonding process and to determine if plating APMT®, a specific highly oxidation-resistant ODS FeCrAl alloy made by Kanthal, onto nickel-based superalloy turbine parts is a viable method for substantially improving the lifetimes and maximum use temperatures of the parts. The superalloys investigated for protection were CM247LC and Rene® 80, both alumina scale-forming alloys. The method for bonding the APMT plate to the superalloys is called evaporative metal bonding, which involves placing a thin foil of zinc between the plate and the superalloy, clamping them together, and heating in an atmosphere-controlled furnace. Upon heating, the zinc melts and dissolves the oxide skins of the alloys at the bond line, allowing the two alloys to diffuse into each other. The zinc then diffuses through the alloys and evaporates from their surfaces, creating a bond between the APMT and the superalloy that is stronger than the APMT itself. Testing showed that the diffusivity of zinc in both APMT and CM247LC is quite similar at 700°C but 15 times higher in the APMT at 1214°C. Coefficients of thermal expansion were determined for each of the alloys as a function of temperature. This information was entered into a finite-element model using ANSYS, which was used to design a clamping jig for pressing the APMT to the superalloys at the bonding temperature. Scanning electron microscopy analyses of representative joints showed that no zinc remained in the alloys after bonding Unfortunately, the analyses also showed some small pieces of broken aluminum oxide scale near the bond lines, indicating that its scale was not sufficiently removed during prebonding cleaning. Samples from each of the bonded blocks were sent to Siemens for

  3. The improvement of corrosion resistance of fluoropolymer coatings by SiO{sub 2}/poly(styrene-co-butyl acrylate) nanocomposite particles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Song, R.G., E-mail: songrg@hotmail.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China); Li, X.W.; Guo, Y.Q.; Wang, C.; Jiang, Y. [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu (China)

    2015-10-30

    Highlights: • We first proposed the feasibility of organic-inorganic hybrid particles can be used to reduce free space of the fluoropolymer coatings. • By grafting poly(styrene-co-butyl acrylate), nano-silica particles can be better dispersed in the fluoropolymer coatings system. • The coating-substrates bound strength could be obviously seen in the FESEM cross-section images. • The effects of the corrosion resistance of fluoropolymer-coated steel were investigated by potentiodynamic polarization and EIS. • Using models to analysis the anticorrosion mechanism of nanocomposite coatings. - Abstract: The effects of nano-silica particles on the anticorrosion properties of fluoropolymer coatings on mild steel have been investigated in this paper. In order to enhance the dispersibility of nano-silica in fluoropolymer coatings, we treated the surface of nano-silica with poly(styrene-co-butyl acrylate) (P(St-BA)). The surface grafting of P(St-BA) on the nanoparticles were detected using Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analyzer (TGA), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The surface of nanocomposite coatings and the coating-substrates bond texture were detected by FE-SEM. We also used energy-dispersive X-ray spectroscopy (EDS) to analyze whether the nanocomposite particles were added into the fluoropolymer coatings. In addition, the influences of various nanoparticles on the corrosion resistance of fluoropolymer-coated steel were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results shown that nanocomposite particles can be dispersed better in fluoropolymer coatings, and the electrochemical results clearly shown the improvement of the protective properties of the nanocomposite coatings when 4 wt.% SiO{sub 2}/P(St-BA) was added to the fluoropolymer coatings.

  4. Assembly of polyaniline nanotubes by interfacial polymerization for corrosion protection.

    Science.gov (United States)

    Oueiny, C; Berlioz, S; Perrin, F X

    2016-02-07

    Polyaniline (PANI) was synthesized by the oxidation of aniline with ammonium peroxydisulfate as an oxidant in an immiscible organic/aqueous biphasic system and with decylphosphonic acid (DPA) or benzylphosphonic acid (BPA) in the aqueous phase. Nanofibers of aniline oligomers were produced using BPA in the aqueous phase while high quality polyaniline nanotubes were produced using DPA in the aqueous phase. PANI nanotubes have a outer diameter 160-240 nm, an inner diameter of 50-100 nm and a length of the order of several μm. The understanding of the formation of PANI nanotubes was examined by isolation of reaction intermediates and their ex situ characterization by atomic force microscopy. The roles of BPA and DPA on the morphology formation of the PANI nanostructures were discussed. A nanofibrillar template produced by aniline oligomers was found to guide the growth of PANI to nanotubular morphology. PANI nanotubes are thus not derived from DPA vesicles. Preliminary corrosion tests exhibit high corrosion protection efficiency of PANI nanotubes because of their high surface area and corrosion inhibitive properties of DPA dopant.

  5. Wear and corrosion behaviour of tungsten carbide based coatings with different metallic binder

    Science.gov (United States)

    Kamdi, Z.; Apandi, M. N. M.; Ibrahim, M. D.

    2017-12-01

    Tungsten carbide based coating has been well known as wear and corrosion resistance materials. However, less study is done on comparing the coating with different binder. Thus, in this work the wear and corrosion behaviour of high velocity oxy-fuel (HVOF) coatings, namely (i) tungsten carbide cobalt and (ii) tungsten carbide nickel will be evaluated. Both coatings were characterised using X-ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). The wear behaviour has been examined using the modified grinder machine by weight loss measurement. Two types of abrasive have been used that include 3 g by weight alumina and silica. While for the corrosion behaviour, it is monitored by three electrodes of electrochemical test and immersion test for 30 days in an acidic environment. The electrolyte used was 0.5 M sulphuric acids (H2SO4). It was found that the cobalt binder shows higher wear resistance compares to the nickel binder for both slurry types. The harder alumina compared to silica results in higher wear rate with removal of carbide and binder is about the same rate. For silica abrasive, due to slightly lower hardness compared to the carbide, the wear is dominated by binder removal followed by carbide detachment. For corrosion, the nickel binder shows four times higher wear resistance compared to the cobalt binder as expected due to its natural behaviour. These finding demonstrate that the selection of coating to be used in different application in this case, wear and corrosion shall be chosen carefully to maximize the usage of the coating.

  6. Chitosan-doped-hybrid/TiO2 nanocomposite based sol-gel coating for the corrosion resistance of aluminum metal in 3.5% NaCl medium.

    Science.gov (United States)

    J, Balaji; M G, Sethuraman

    2017-11-01

    The study outlines the role of chitosan, a biopolymer on corrosion behavior of Hy/nano-TiO2 based sol-gel coating over aluminum metal. In this study organic-inorganic hybrid sols were synthesized through hydrolysis and condensation of 3-glycidoxypropyltrimethoxy silane (GPTMS), tetraethoxysilane (TEOS) and titanium (IV) isopropoxide (TIP) in acidic solution. Chitosan was doped into sol-gel matrix and self-assembled over aluminum substrate. The resultant chitosan-doped-Hy/nano-TiO2 sol-gel coating was characterized by Fourier Transform Infrared (FT-IR) spectra, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Energy-Dispersive X-ray Spectroscopy (EDX) analyses. The as-tailored aluminum substrate was evaluated for corrosion resistance in neutral medium. The protection ability of these coatings was evaluated by electrochemical impedance studies (EIS) and potentiodynamic polarization (PP) measurements in 3.5% NaCl medium. The EIS and PP results showed that chitosan-doped- Hy/nano-TiO2 sol-gel coating exhibited better protection from corrosion than the undoped Hy/TiO2 nanocomposite coating. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Qualification of thermal sprayed corrosion coatings of thick-walled components (QUAKOS). Final report; Qualifizierung thermisch gespritzter Korrosionsschutzschichten fuer dickwandige Behaelterkomponenten. QUAKOS. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Tragsdorf, Inga Maren

    2015-11-15

    During the interim storage of thick-walled transport and storage components, damages at the surface may occur which break up the corrosion protection and thus may cause complex repair works during the operation period. The method of high velocity oxygen-fuel coating is intending to optimize the resulting requirements. In connection with loading of casks, parallelly, the application of more corrosion resistant, impact and scratch resistant inside coatings of casks is examined under consideration of an interim storage which time period is not foreseeable at present. The method of applying high velocity oxygen-fuel is generating dense sprayed coatings with excellent adhesive properties. This method is particularly suitable for generating extremely thin layers with a high grade of accuracy and low porosity; even a repair of defects is easy. In the project, different spraying powders (Metco 15F, Diamalloy 2001 and Hoeganaes 1660.02) are examined as spraying material for corrosion protection of the work material ductile graphite cast iron. An extensive pre-examination programme with an additional thermal spray method (arc wire) provides the basis for coating of a thick-walled small component. Coating of the small component is presented under consideration of procedural optimization and the examination methods (water tests and salt spray tests)

  8. Corrosion kinetics of 316L stainless steel bipolar plate with chromiumcarbide coating in simulated PEMFC cathodic environment

    Directory of Open Access Journals (Sweden)

    N.B. Huang

    Full Text Available Stainless steel with chromium carbide coating is an ideal candidate for bipolar plates. However, the coating still cannot resist the corrosion of a proton exchange membrane fuel cell (