Evaluation of self-healing ability in protective coatings modified with combinations of layered double hydroxides and cerium molibdate nanocontainers filled with corrosion inhibitors

International Nuclear Information System (INIS)

Montemor, M.F.; Snihirova, D.V.; Taryba, M.G.; Lamaka, S.V.; Kartsonakis, I.A.; Balaskas, A.C.; Kordas, G.C.; Tedim, J.; Kuznetsova, A.; Zheludkevich, M.L.; Ferreira, M.G.S.

2012-01-01

Nowadays, there is a strong demand on the search of thinner, but more effective organic coatings for corrosion protection of metallic substrates, like galvanised steel, used in the automotive industry. In order to guarantee effective corrosion protection of these coatings, and because chromate-based pigments cannot be used, one of the most attractive strategies consists on the modification of the organic matrix with nano-additives filled with corrosion inhibitors, which can be released to the active sites. In this work, two different nano-additives are explored as potential self-healing materials for the development of active protective coatings. These additives are layered double hydroxides and cerium molybdate hollow nanospheres loaded with mercaptobenzothiazole, as a corrosion inhibitor. These additives were added to epoxy primers, individually, or combining the two nanoadditives in the same layer. The electrochemical behaviour and the potential of self-healing ability were studied by electrochemical impedance spectroscopy, scanning vibrating electrode technique and scanning ion-selective electrode technique. The results reveal that both types of nanocontainers can provide effective corrosion inhibition on artificial induced defects, at different stages of the degradation process. Moreover, the results also show that there is a synergistic effect concerning corrosion inhibition and self-healing potential when a mixture of the two nanocontainers is used. The mechanism of self healing is presented and discussed in terms of effect of organic inhibitor and role of the nanocontainers, including effect of cerium ions released from cerium molibdate nanoparticles.

Durable Corrosion Resistance of Copper Due to Multi-Layer Graphene

Directory of Open Access Journals (Sweden)

Abhishek Tiwari

2017-09-01

Full Text Available Ultra-thin graphene coating has been reported to provide considerable resistance against corrosion during short-term exposures, however, there is great variability in the corrosion resistance due to graphene coating in different studies. It may be possible to overcome the problem of hampered corrosion protection ability of graphene that is caused due to defective single layer graphene by applying multilayer graphene. Systematic electrochemical characterization showed that the multilayer graphene coating developed in the study provided significant corrosion resistance in a chloride solution and the corrosion resistance was sustained for long durations (~400 h, which is attributed to the multilayer graphene.

Protective layer formation on magnesium in cell culture medium.

Science.gov (United States)

Wagener, V; Virtanen, S

2016-06-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO2). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37°C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous structures. The

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.

Protective layer formation on magnesium in cell culture medium

Energy Technology Data Exchange (ETDEWEB)

Wagener, V.; Virtanen, S., E-mail: virtanen@ww.uni-erlangen.de

2016-06-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO{sub 2}). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37 °C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous

Protective layer formation on magnesium in cell culture medium

International Nuclear Information System (INIS)

Wagener, V.; Virtanen, S.

2016-01-01

In the past, different studies showed that hydroxyapatite (HA) or similar calcium phosphates can be precipitated on Mg during immersion in simulated body fluids. However, at the same time, in most cases a dark grey or black layer is built under the white HA crystals. This layer seems to consist as well of calcium phosphates. Until now, neither the morphology nor its influence on Mg corrosion have been investigated in detail. In this work commercially pure magnesium (cp) was immersed in cell culture medium for one, three and five days at room temperature and in the incubator (37 °C, 5% CO_2). In addition, the influence of proteins on the formation of a corrosion layer was investigated by adding 20% of fetal calf serum (FCS) to the cell culture medium in the incubator. In order to analyze the formed layers, SEM images of cross sections, X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transformed Infrared Spectroscopy (FTIR) measurements were carried out. Characterization of the corrosion behavior was achieved by electrochemical impedance spectroscopy (EIS) and by potentio-dynamic polarization in Dulbecco's Modified Eagle's Medium (DMEM) at 37 °C. Surface analysis showed that all formed layers consist mainly of amorphous calcium phosphate compounds. For the immersion at room temperature the Ca/P ratio indicates the formation of HA, while in the incubator probably pre-stages to HA are formed. The different immersion conditions lead to a variation in layer thicknesses. However, electrochemical characterization shows that the layer thickness does not influence the corrosion resistance of magnesium. The main influencing factor for the corrosion behavior is the layer morphology. Thus, immersion at room temperature leads to the highest corrosion protection due to the formation of a compact outer layer. Layers formed in the incubator show much worse performances due to completely porous structures. The

Electrodeposition, characterization and corrosion investigations of galvanic tin-zinc layers from pyrophosphate baths

OpenAIRE

STOPIC MILENA D.; FRIEDRICH BERND G.

2016-01-01

Tin-zinc alloy deposits are recognized as a potential alternative to toxic cadmium as corrosion resistant coatings. Tin-zinc alloy layers offer outstanding corrosion protection for steel by combining the barrier protection of tin with the galvanic protection of zinc. Tin-zinc coatings have been used on the chassis of electrical and electronic apparatus and on critical automotive parts such as fuel and brake line components. In this study, tin-zinc alloy deposits were successfully prepared fro...

Mechanism of protective action of surface carbide layers on titanium

International Nuclear Information System (INIS)

Chukalovskaya, T.V.; Chebotareva, N.P.; Tomashov, N.D.

1990-01-01

The protective action of surface carbide layer on titanium produced in methane atmosphere at 1000 deg C and under 6.7 kPa pressure in H 2 SO 4 solutions is studied through comparison of microsection metallographic specimens prior to and after corrosion testing (after specimen activation); through comparison of anodic characteristics after partial stripping of the layer up to its complete stripping; through analysis of the behaviour of Ti-TiC galvanic couple, and through investigation of corresponding corrosion diagrams under test conditions. It is shown that screening protective mechanism is primarily got involved in highly agressive media (high temperature and concentration of solution), and in less agressive environment the protection of titanium with carbide layer is primarily ensured by electrochemical mechanism

Zinc/manganese multilayer coatings for corrosion protection

International Nuclear Information System (INIS)

Muenz, R.; Wolf, G.K.; Guzman, L.; Adami, M.

2004-01-01

Zn alloys are able to surpass the performance of electrogalvanised or hot-dip Zn (at same thickness) for corrosion protection of car bodies. In particular, vacuum deposited Zn alloy layers have higher protection power on non-painted steel surfaces as compared with pure Zn layers. In the present work the Zn-Mn system was investigated: Zn/Mn alloys of different compositions as well as Zn/Mn multilayers of 5-6 μm total thickness were prepared on low alloy steel by ion beam assisted deposition (IBAD). The equipment contained two electron beam evaporators and a slit extraction ion source, delivering ions of 100-1500 eV energy. The corrosion behaviour of the samples was evaluated by standard salt spray tests (SST). The composition and microstructure of the coatings was studied by scanning electron microscopy (SEM) and EDX-depth profiling. The behaviour of the coating/substrate system is discussed in comparison with 'state of the art' Zn-coatings (EZ) produced by electrogalvanizing. Generally speaking, the performance of the optimised coatings is as good or better than the reference standard

Catalysts, Protection Layers, and Semiconductors

DEFF Research Database (Denmark)

Chorkendorff, Ib

2015-01-01

Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

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.

Corrosion behavior and protective ability of Zn and Zn-Co electrodeposits with embedded polymeric nanoparticles

International Nuclear Information System (INIS)

Boshkov, N.; Tsvetkova, N.; Petrov, P.; Koleva, D.; Petrov, K.; Avdeev, G.; Tsvetanov, Ch.; Raichevsky, G.; Raicheff, R.

2008-01-01

The anodic behavior, corrosion resistance and protective ability of Zn and alloyed Zn-Co (∼3 wt.%) nanocomposite coatings were investigated in a model corrosion medium of 5% NaCl solution. The metallic matrix of the layers incorporates core-shell nano-sized stabilized polymeric micelles (SPMs) obtained from poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block co-polymers. The protective properties of the composite coatings were evaluated using potentiodynamic polarization technique, polarization resistance measurements and powder X-ray diffraction. The sizes and distribution of the stabilized polymeric micelles in the starting electrolytes used as well as in the metal matrices of the layers were investigated using scanning and transmission electron microscopy. The results obtained are compared to those of electrodeposited Zn and Zn-Co (∼3 wt.%) alloy coatings at identical conditions and demonstrate the enhanced protective characteristics of the Zn nanocomposites during the investigating period. The influence of the SPMs on the corrosion resistance of the nanocomposite layers is commented and discussed

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.

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

OpenAIRE

Abdulkareem Mohammed Ali Al-Sammarraie; Mazin Hasan Raheema

2017-01-01

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 therm...

Influence of corrosion layers on quantitative analysis

International Nuclear Information System (INIS)

Denker, A.; Bohne, W.; Opitz-Coutureau, J.; Rauschenberg, J.; Roehrich, J.; Strub, E.

2005-01-01

Art historians and restorers in charge of ancient metal objects are often reluctant to remove the corrosion layer evolved over time, as this would change the appearance of the artefact dramatically. Therefore, when an elemental analysis of the objects is required, this has to be done by penetrating the corrosion layer. In this work the influence of corrosion was studied on Chinese and Roman coins, where removal of oxidized material was possible. Measurements on spots with and without corrosion are presented and the results discussed

Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

Energy Technology Data Exchange (ETDEWEB)

Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

2015-10-15

In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

Corrosion of metallic materials. Dry corrosion, aqueous corrosion and corrosion by liquid metal, methods of protection

International Nuclear Information System (INIS)

Helie, Max

2015-01-01

This book is based on a course on materials given in an engineering school. The author first gives an overview of metallurgy issues: metallic materials (pure metals, metallic alloys), defects of crystal lattices (point defects, linear defects or dislocations), equilibrium diagrams, steels and cast, thermal processing of steels, stainless steels, aluminium and its alloys, copper and its alloys. The second part addresses the properties and characterization of surfaces and interfaces: singularity of a metal surface, surface energy of a metal, energy of grain boundaries, adsorption at a material surface, metal-electrolyte interface, surface oxide-electrolyte interface, techniques of surface analysis. The third chapter addresses the electrochemical aspects of corrosion: description of the corrosion phenomenon, free enthalpy of a compound and free enthalpy of a reaction, case of dry corrosion (thermodynamic aspect, Ellingham diagram, oxidation mechanisms, experimental study, macroscopic modelling), case of aqueous corrosion (electrochemical thermodynamics and kinetics, experimental determination of corrosion rate). The fourth part addresses the different forms of aqueous corrosion: generalized corrosion (atmospheric corrosion, mechanisms and tests), localized corrosion (galvanic, pitting, cracking, intergranular, erosion and cavitation), particular cases of stress cracking (stress corrosion, fatigue-corrosion, embrittlement by hydrogen), and bi-corrosion (of non alloyed steels, of stainless steels, and of aluminium and copper alloys). The sixth chapter addresses the struggle and the protection against aqueous corrosion: methods of prevention, scope of use of main alloys, geometry-based protection of pieces, use of corrosion inhibitors, use of organic or metallic coatings, electrochemical protection. The last chapter proposes an overview of corrosion types in industrial practices: in the automotive industry, in the oil industry, in the aircraft industry, and in the

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.

Characterization of corrosion resistant on NiCoCr coating layer exposed to 5%NaCl

Science.gov (United States)

Sugiarti, E.; Sundawa, R.; Desiati, R. D.; Zaini, K. A.

2018-03-01

Highly corrosion resistant of carbon steel coated NiCoCr was applied in corrosive of marine environtment. Carbon steel coated NiCoCr was prepared by a two step technique of NiCo electro-deposition and Cr pack cementation. The samples were exposed to 5 wt.% NaCl for 48 and 168 hours. The microstructure and corrosion product were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The corrosion resistance of carbon steel coated NiCoCr was found to be better than that of carbon steel substrate without coating. The results showed the microstructure of 48 h corroded sample has duplex layer composed of inner α-(Ni,Co), α-Cr and outer Cr2O3, while a quite thin and continues protective oxide of Cr2O3 was observed in outer layer of 168 h corroded sample. The formation of oxide scale rich in Cr2O3 has contributed for the better corrosion resistance of carbon steel coated NiCoCr, whereas the formation of non protective oxide of iron might caused low corrosion resistance of carbon steel substrate.

Achievments of corrosion science and corrosion protection technology

International Nuclear Information System (INIS)

Fontana, M.; Stehjl, R.

1985-01-01

Problems of corrosion-mechanical strength of metals, effect of corrosive media on creep characteristics are presented. New concepts of the mechanism of corrosion cracking and its relation to hydrogen embrittlement are described. Kinetics and mechanism of hydrogen embrittlement effect on the process of corrosion cracking of different steels and alloys are considered. The dependence of such types of failure on various structural factors is shown. Data on corrosion cracking of high-strength aluminium and titanium alloys, mechanism of the processes and protective methods are given

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

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 ...

Corrosion and corrosion protection of support structures for offshore wind energy devices (OWEA)

Energy Technology Data Exchange (ETDEWEB)

Momber, A. [Muehlhan AG, Schlinckstrasse 3, D-21107 Hamburg (Germany)

2011-05-15

The paper provides a review about the corrosion and corrosion protection of offshore wind energy devices (OWEA). Firstly, special features resulting from location and operation of OWEA are being discussed. Secondly, types of corrosion and corrosion phenomena are summarized in a systematic way. Finally, practical solutions to the corrosion protection of OWEA, including steel allowances, cathodic protection and coatings and linings, are discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Bilayers Polypyrrole Coatings for Corrosion Protection of SAE 4140 Steel

OpenAIRE

Lehr, I.L.; Saidman, S.B.

2014-01-01

In this study polypyrrole (PPy) bilayers films were electrodeposited onto SAE 4140 steel. The inner layer was electropolymerized in the presence of molibdate and nitrate and the outer layer in a solution containing sodium bis (2-ethylhexyl) sulfosuccinate (AOT). The electrosynthesis was done under potentiostatic conditions. The corrosion protection properties of the films were examined in sodium chloride solution by open circuit measurements, linear polarization and electrochemical impedance ...

Corrosion of pure magnesium under thin electrolyte layers

International Nuclear Information System (INIS)

Zhang Tao; Chen Chongmu; Shao Yawei; Meng Guozhe; Wang Fuhui; Li Xiaogang; Dong Chaofang

2008-01-01

The corrosion behavior of pure magnesium was investigated by means of cathodic polarization curve, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) under aerated and deaerated thin electrolyte layers (TEL) with various thicknesses. Based on shot noise theory and stochastic theory, the EN results were quantitatively analyzed by using the Weibull and Gumbel distribution function, respectively. The results show that the cathodic process of pure magnesium under thin electrolyte layer was dominated by hydrogen reduction. With the decreasing of thin electrolyte layer thickness, cathodic process was retarded slightly while the anodic process was inhibited significantly, which indicated that both the cathodic and anodic process were inhibited in the presence of oxygen. The absence of oxygen decreased the corrosion resistance of pure magnesium in case of thin electrolyte layer. The corrosion was more localized under thin electrolyte layer than that in bulk solution. The results also demonstrate that there exist two kinds of effects for thin electrolyte layer on the corrosion behavior of pure magnesium: (1) the rate of pit initiation was evidently retarded compared to that in bulk solution; (2) the probability of pit growth oppositely increased. The corrosion model of pure magnesium under thin electrolyte layer was suggested in the paper

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.

Silicate glasses corrosion. Texture analysis of the corrosion layer

International Nuclear Information System (INIS)

Portal, Sabine

2001-01-01

We have studied the kinetic and the texture evolution of the corroded layer that forms on glass surfaces exposed to acidic solutions. The corroded layer is depleted in alkali cations and is produced by an ion exchange mechanism. It is porous and shows a lower refractive index than the one of the bulk glass. Spectroscopic ellipsometry allows determining the thickness of the layer and its refractive index. Several other techniques have been developed for characterizing the corrosion behaviour of glass surfaces: porosity is thus investigated by adsorption-desorption of nitrogen; the thickness and the composition of the layer are studied by secondary ion mass spectroscopy (S.I.M.S.); sodium concentration in the solution has been analyzed by atomic absorption. This study shows the importance of leaching conditions and glass preparation. The type of drying employed is susceptible to modify the texture and the structure of the layer. The layers produced in the early stages of the leaching process are not easily detectable. The different results lead however to the same conclusion: after a strong increase of porosity, a densification of the layer is observed with increasing time. The evolution of the layer texture could therefore modify the kinetic of the glass corrosion. (author) [fr

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 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine...

Polystyrene films as barrier layers for corrosion protection of copper and copper alloys.

Science.gov (United States)

Románszki, Loránd; Datsenko, Iaryna; May, Zoltán; Telegdi, Judit; Nyikos, Lajos; Sand, Wolfgang

2014-06-01

Dip-coated polystyrene layers of sub-micrometre thickness (85-500nm) have been applied on copper and copper alloys (aluminium brass, copper-nickel 70/30), as well as on stainless steel 304, and produced an effective barrier against corrosion and adhesion of corrosion-relevant microorganisms. According to the dynamic wettability measurements, the coatings exhibited high advancing (103°), receding (79°) and equilibrium (87°) contact angles, low contact angle hysteresis (6°) and surface free energy (31mJ/m(2)). The corrosion rate of copper-nickel 70/30 alloy samples in 3.5% NaCl was as low as 3.2μm/a (44% of that of the uncoated samples), and in artificial seawater was only 0.9μm/a (29% of that of the uncoated samples). Cell adhesion was studied by fluorescence microscopy, using monoculture of Desulfovibrio alaskensis. The coatings not only decreased the corrosion rate but also markedly reduced the number of bacterial cells adhered to the coated surfaces. The PS coating on copper gave the best result, 2×10(3)cells/cm(2) (1% of that of the uncoated control). © 2013 Elsevier B.V. All rights reserved.

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...

Enhanced corrosion resistance of magnesium alloy by a silane-based solution treatment after an in-situ formation of the Mg(OH)2 layer

Science.gov (United States)

Gong, Fubao; Shen, Jun; Gao, Runhua; Xie, Xiong; Luo, Xiong

2016-03-01

A novel organic-inorganic Mg(OH)2/silane surface layer has been developed for corrosion protection of AZ31 magnesium alloy. The results of electrochemical impedance spectroscopy (EIS), the immersion tests, Fourier-transform infrared spectroscopy (FTIR) and sellotape tests showed that the Mg(OH)2/silane-based composite surface layer possessed excellent corrosion resistance and very good adhesion due to the formation of Si-O-Mg bond between Mg(OH)2 layer and silane layer. Electrochemical impedance spectroscopy tests results indicated that for the long-term corrosion protection of AZ31 the increase of the curing temperature improved the impedance of the composited layer when the curing temperature was lower than 130 °С. However, the impedance of the composited layer deceased when the curing temperature was more than 130 °С due to the carbonization of the silane layer.

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.

Understanding corrosion via corrosion product characterization: II. Role of alloying elements in improving the corrosion resistance of Zn-Al-Mg coatings on steel

International Nuclear Information System (INIS)

Volovitch, P.; Vu, T.N.; Allely, C.; Abdel Aal, A.; Ogle, K.

2011-01-01

Highlights: → Origins of better corrosion resistance of ZnAlMg coatings than galvanized steel. → Comparative study of corrosion products formed on ZnAlMg, ZnMg and Zn coatings. → Modeling of dissolution and precipitation stages of corrosion. → At early stages Mg stabilizes protective zinc basic salts during dry-wet cycling. → At later stages Al dissolves at high pH forming protective layered double hydroxides. - Abstract: Corrosion products are identified on Zn, ZnMg and ZnAlMg coatings in cyclic corrosion tests with NaCl or Na 2 SO 4 containing atmospheres. For Mg-containing alloys the improved corrosion resistance is achieved by stabilization of protective simonkolleite and zinc hydroxysulfate. At later stages, the formation of layered double hydroxides (LDH) is observed for ZnAlMg. According to thermodynamic modeling, Mg 2+ ions bind the excess of carbonate or sulfate anions preventing the formation of soluble or less-protective products. A preferential dissolution of Zn and Mg at initial stages of corrosion is confirmed by in situ dissolution measurement. The physicochemical properties of different corrosion products are compared.

Mechanism of pitting corrosion protection of metals and alloys in new-generation water treatment plants

Directory of Open Access Journals (Sweden)

Grachev Vladimir

2017-01-01

Full Text Available In this article authors set out a principle of pitting corrosion protection, suggested a new class of multilayer materials with high corrosion resistance. They substantiated the choice of the layers for the multilayer material designed for exploitation in oxidizing and non-oxidizing environment. The sphere of application of the multilyer materials was defined.

Protection of copper surface with phytic acid against corrosion in chloride solution.

Science.gov (United States)

Peca, Dunja; Pihlar, Boris; Ingrid, Milošev

2014-01-01

Phytic acid (inositol hexaphosphate) was tested as a corrosion inhibitor for copper in 3% sodium chloride. Phytic acid is a natural compound derived from plants, it is not toxic and can be considered as a green inhibitor. Electrochemical methods of linear polarization and potentiodynamic polarization were used to study the electrochemical behaviour and evaluate the inhibition effectiveness. To obtain the optimal corrosion protection the following experimental conditions were investigated: effect of surface pre-treatment (abrasion and three procedures of surface roughening), pre-formation of the layer of phytic acid, time of immersion and concentration of phytic acid. To evaluate the surface pre-treatment procedures the surface roughness and contact angle were measured. Optimal conditions for formation of phytic layer were selected resulting in the inhibition effectiveness of nearly 80%. Morphology and composition of the layer were further studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The layer of phytic acid with thickness in the nanometer range homogeneously covers the copper surface. The obtained results show that this natural compound can be used as a mildly effective corrosion inhibitor for copper in chloride solution.

An Investigation on Corrosion Behavior of a Multi-layer Modified Aluminum Brazing Sheet

Directory of Open Access Journals (Sweden)

Liu Wei

2016-01-01

Full Text Available The corrosion behavior of a multi-layer modified aluminum brazing sheet (AA4045/3003Mod./AA7072/AA4045 was investigated. The results shows that, the existence of BDP, which forms at the interface between clad and core layer during brazing, changes the corrosion form of the air side of the material from inter-granular corrosion to local exfoliation corrosion. The addition of anti-corrosion layer makes the corrosion form of the water side from inter-granular corrosion into uniform exfoliation corrosion. Compared to the normal triple-layer brazing sheet at the same thickness, the time to perforation of the modified four-layer brazing sheet is increased by more than 200%.

Study of the mechanical properties of single- layer and multi-layer metallic coatings with protective-decorative applications

Directory of Open Access Journals (Sweden)

Cherneva Sabina

2018-01-01

Full Text Available Single thin coating of matt nickel (Nimat, a mirror bright copper (Cubright, a mirror bright nickel (Nibright and their combinations were electrochemically deposited on brass substrate with thickness 500 μm. The basic aim was electrodeposition of two-layer Cubright/Nimat and Nibright/Cubright systems, and three-layer Nibright Cubrigh/Nimat system, which are among the most widely applied protective and decorative systems in light and medium operating conditions of corrosion. The thicknesses of the obtained films varied from 1 μm to 3.25 μm. They were investigated via nanoindentation experiments, in order to characterize their basic physical and mechanical characteristics, related with their good adhesion and corrosion protective ability, as well as ensuring the integrity of the system “protective coating/substrate” to possible mechanical, dynamic and/or thermal stresses. As a result, load-displacement curves were obtained and indentation hardness and indentation modulus were calculated using the Oliver & Pharr approximation method. The dependence of the indentation modulus and the indentation hardness on the depth of the indentation, surface morphology and structure of the obtained coatings, their texture and surface roughness were investigated too. The obtained results showed that the three-layer Nibright/Cubright /Niimat/CuZn37 system has highest indentation modulus and indentation hardness, following by two-layer Nibright/Cubright system and single layer coatings.

Studies on yttrium oxide coatings for corrosion protection against molten uranium

International Nuclear Information System (INIS)

Chakravarthy, Y.; Bhandari, Subhankar; Pragatheeswaran; Thiyagarajan, T.K.; Ananthapadmanabhan, P.V.; Das, A.K.; Kumar, Jay; Kutty, T.R.G.

2012-01-01

Yttrium oxide is resistant to corrosion by molten uranium and its alloys. Yttrium oxide is recommended as a protective oxide layer on graphite and metal components used for melting and processing uranium and its alloys. This paper presents studies on the efficacy of plasma sprayed yttrium oxide coatings for barrier applications against molten uranium

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......: • 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 acidiWcation in Wrst steps of corrosion on EB coated aluminium surfaces....

Localized Corrosion Behavior of Type 304SS with a Silica Layer Under Atmospheric Corrosion Environments

International Nuclear Information System (INIS)

E. Tada; G.S. Frankel

2006-01-01

The U.S. Department of Energy (DOE) has proposed a potential repository for spent nuclear fuel and high-level radioactive waste at the Yucca Mountain site in Nevada. [I] The temperature could be high on the waste packages, and it is possible that dripping water or humidity could interact with rock dust particulate to form a thin electrolyte layer with concentrated ionic species. Under these conditions, it is possible that highly corrosion-resistant alloys (CRAs) used as packages to dispose the nuclear waste could suffer localized corrosion. Therefore, to better understand long-term corrosion performance of CRAs in the repository, it is important to investigate localized corrosion under a simulated repository environment. We measured open circuit potential (OCP) and galvanic current (i g ) for silica-coated Type 304SS during drying of salt solutions under controlled RH environments to clarify the effect of silica layer as a dust layer simulant on localized corrosion under atmospheric environments. Type 304SS was used as a relatively susceptible model CRA instead of the much more corrosion resistant alloys, such as Alloy 22, that are being considered as, waste package materials

Materials corrosion and protection at high temperatures

International Nuclear Information System (INIS)

Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien; Duhamel, Cecile; Marchetti, Loic; Perrin, Stephane; Molins, Regine; Chevalier, S.; Heintz, O.; David, N.; Fiorani, J.M.; Vilasi, M.; Wouters, Y.; Galerie, A.; Mangelinck, D.; Viguier, B.; Monceau, D.; Soustelle, M.; Pijolat, M.; Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K.; Wolski, K.; Barnier, V.; Rebillat, F.; Lavigne, O.; Brossard, J.M.; Ropital, F.; Mougin, J.

2011-01-01

This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

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.

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.

Corrosion behaviour in saline environments of single-layer titanium and aluminium coatings, and of Ti/Al alternated multi-layers elaborated by a multi-beam PVD technique

International Nuclear Information System (INIS)

Merati, Abdenacer

1994-01-01

This research thesis reports the characterization of anti-corrosion titanium and aluminium coatings deposited on a 35CD4 steel under the form of mono-metallic layers or alternated Ti/Al multi-layers, and obtained by a multibeam PVD technique. The influence of different parameters is studied: single-layer thickness (5, 15 or 30 micro-metres), multi-layer distribution (5 to 6) and substrate (smooth or threaded). Layer nature and microstructure are studied by optical microscopy and scanning electron microscopy (SEM), as well as corrosion toughness in aqueous saline environments. Coated threaded samples have been studied after tightening tests. It appears that titanium layers are denser and more uniform than aluminium layers, and that multi-layer coatings provide a better protection than single-layer coatings. The best behaviour is obtained when titanium is in contact with steel, and aluminium is the outer layer in contact with the corroding environment [fr

Corrosion and protection of aluminum alloys in seawater

Energy Technology Data Exchange (ETDEWEB)

Nisancioglu Kemal [Department of Materials Technology, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2004-07-01

The paper deals with pitting and uniform corrosion and effectiveness of cathodic protection in reducing these corrosion forms. In stagnant waters or presence of low flow rates, pitting may occur. However, pitting corrosion, driven by the Fe-rich cathodic intermetallic compounds, is often of superficial nature. The pits tend to passivate as a result of etching or passivation of the intermetallics with time. Cathodic protection is an effective way of preventing pitting. It also requires low current densities since the cathodic area, defined by the Fe-rich intermetallics, is small in contrast to steel, which is uniformly accessible to the cathodic reaction. Although thermodynamic calculations suggest possible instability of the oxide in slightly alkaline solutions, such as seawater, protective nature of the oxide in practice is attributed to the presence of alloying elements such as Mg and Mn. Thus, the passivity of both the aluminum matrix alloy (the anode) and the intermetallics (cathodes) have to be considered in evaluating the corrosion and protection of aluminum alloys. With increasing flow rate, the possibility of pitting corrosion reduces with increase in the rate of uniform corrosion, which is controlled by the flow dependent chemical dissolution of the oxide. Cathodic protection does not stop this phenomenon, and coatings have to be used. (authors)

Characterization of the corrosion protection mechanism of cerium-based conversion coatings on high strength aluminum alloys

Science.gov (United States)

Pinc, William Ross

The aim of the work presented in this dissertation is to investigate the corrosion protection mechanism of cerium-based conversion coatings (CeCCs) used in the corrosion protection of high strength aluminum alloys. The corrosion resistance of CeCCs involves two general mechanisms; barrier and active. The barrier protection mechanism was influenced by processing parameters, specifically surface preparation, post-treatment, and the use of gelatin. Post-treatment and the addition of gelatin to the coating solution resulted in fewer cracks and transformation of the coating to CePO4, which increased the corrosion resistance by improving the barrier aspect of CeCCs. CeCCs were found to best act as barriers when crack size was limited and CePO4 was present in the coating. CeCCs were found to protect areas of the substrate that were exposed in the coating, indicating that the coatings were more than simple barriers. CeCCs contained large cracks, underneath which subsurface crevices were connected to the surface by the cracks. Despite the observation that no cerium was present in crevices, coatings with crevices exhibited significant corrosion protection. The impedance of post-treated coatings with crevices increased during salt spray exposure. The increase in impedance was associated with the formation of protective oxides / hydroxides; however, crevice-free coatings also exhibited active protection leading to the conclusion that the formation of interfacial layers between the CeCC and the substrate also contributed to the active protection. Based on the overall results of the study, the optimal corrosion protection of CeCCs occurred when processing conditions produced coatings with morphologies and compositions that facilitated both the barrier and active protection mechanisms.

Inorganic coatings on stainless steel for protection against crevice corrosion

International Nuclear Information System (INIS)

Henrikson, Sture

1989-12-01

In order to create protection against crevice corrosion stainless steel test specimens of type 316 steel with various inorganic coatings applied on crevice surfaces were tested for 3-50 months at 25 and 30 degree C in natural seawater containing 0.2-1.5 ppm free chlorine. Various metallic coatings, Ni base alloys with Cr and Mo, Ni with W, pure Ag and pure Mo, as well as ceramic coatings - Cr 2 O 3 , TiO 2 and Al 2 O 3 - were studied. All the coatings tested, except pure Molybdenum applied by plasma spraying in a max 0.1 mm thick layer were found to promote crevice corrosion of the stainless steel. A significant reduction of the crevice corrosion susceptibility was obtained with Molybdenum. The result is considered promising enough to justify full scale tests in seawater on flange joints of pipes, valves or pumps. (author)

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.

Promoting Barrier Performance and Cathodic Protection of Zinc-Rich Epoxy Primer via Single-Layer Graphene

Directory of Open Access Journals (Sweden)

Jingrong Liu

2018-05-01

Full Text Available The effect of single-layer graphene sheets (Gr on the corrosion protection of zinc-rich epoxy primers (ZRPs was investigated. Scanning electron microscopy (SEM with an energy dispersive spectrometer (EDS were used to characterize morphology and composition of the coatings after immersion for 25 days. The cross-sectional SEM images and X-ray photoelectron spectroscopy (XPS confirmed that the addition of single-layer graphene facilitated assembling of zinc oxides on the interface between the coating and the steel. The open circuit potential (OCP, electrochemical impedance spectroscopy (EIS measurements revealed that both the cathodic protection and barrier performance of the ZRP were enhanced after addition of 0.6 wt. % Gr (Gr0.6-ZRP. In addition, the cathodic protection property of the Gr0.6-ZRP was characterized quantitatively by localized electrochemical impedance spectroscopy (LEIS in the presence of an artificial scratch on the coating. The results demonstrate that moderate amounts of single-layer graphene can significantly improve corrosion resistance of ZRP, due to the barrier protection and cathodic protection effects.

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion

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Ana Chira

2017-02-01

Full Text Available Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctylaniline, 4-aminoantipyrine, 4-(4-aminophenylbutyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM. The electrodeposited mass varies between 26 ng/cm2 for 4-fluoroaniline formed during 30 s to 442 ng/cm2 for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenylbutyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

Electrodeposited Organic Layers Formed from Aryl Diazonium Salts for Inhibition of Copper Corrosion.

Science.gov (United States)

Chira, Ana; Bucur, Bogdan; Radu, Gabriel-Lucian

2017-02-28

Copper substrates deposed on a gold screen-printed electrode were covered with different aryl diazonium salts by electrodeposition at 0.25 mA for 30 or 300 s. Seven compounds were investigated: 4-aminophenylacetic acid, 4-aminophenethyl alcohol, 4-fluoroaniline, 4-(heptadecafluorooctyl)aniline, 4-aminoantipyrine, 4-(4-aminophenyl)butyric acid and 3,4,5-trimethoxyaniline. Quantitative monitoring of the electrodeposition process was carried out by electrogravimetry using quartz crystal microbalance (QCM). The electrodeposited mass varies between 26 ng/cm² for 4-fluoroaniline formed during 30 s to 442 ng/cm² for 4-phenylbutyric acid formed during 300 s. The corrosion inhibition properties of aryl-modified layers have been studied in buffer citrate with pH = 3 or 3.5% NaCl solutions using electrochemical noise (ECN) and Tafel potentiodynamic polarization measurements. A corrosion inhibiting efficiency up to 90% was found. The highest corrosion inhibition was obtained for 4-(4-aminophenyl)butyric acid and the lowest for 4-fluoroaniline. A relation between the inhibition efficiency and the chemical nature of the substituents in the protective layer was found.

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.

Protection of Steel Corrosion in Concrete Members by the Combination of Galvanic Anode and Nitrite Penetration

Directory of Open Access Journals (Sweden)

Minobu Aoyama

2014-01-01

Full Text Available Chloride induced-corrosion of steel bars in concrete can make cracks and exfoliation in near-surface regions in reinforced concrete structures. In this paper, we described the basic concept and practice of steel bars corrosion protection method by the combination of galvanic anode (zinc wire and the penetration of nitrite ions from mortar layers containing a large amount of lithium nitrite.

Accelerated Test Method for Corrosion Protective Coatings

Data.gov (United States)

National Aeronautics and Space Administration — This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as...

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

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.

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.

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.

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.

Surface layer effects on waste glass corrosion

International Nuclear Information System (INIS)

Feng, X.

1993-01-01

Water contact subjects waste glass to chemical attack that results in the formation of surface alteration layers. Two principal hypotheses have been advanced concerning the effect of surface alteration layers on continued glass corrosion: (1) they act as a mass transport barrier and (2) they influence the chemical affinity of the glass reaction. In general, transport barrier effects have been found to be less important than affinity effects in the corrosion of most high-level nuclear waste glasses. However, they can be important under some circumstances, for example, in a very alkaline solution, in leachants containing Mg ions, or under conditions where the matrix dissolution rate is very low. The latter suggests that physical barrier effect may affect the long-term glass dissolution rate. Surface layers influence glass reaction affinity through the effects of the altered glass and secondary phases on the solution chemistry. The reaction affinity may be controlled by various precipitates and crystalline phases, amorphous silica phases, gel layer, or all the components of the glass. The surface alteration layers influence radionuclide release mainly through colloid formation, crystalline phase incorporation, and gel layer retention. This paper reviews current understanding and uncertainties

Texture of altered layers issued from glass corrosion

International Nuclear Information System (INIS)

Phalippou, J.; Woignier, Th.; Ayral, A.

1997-01-01

The layers which develop at the glass surface subjected to water corrosion depend on a collection of interacting parameters. Such a material can be studied using techniques which have been previously demonstrated as suitable for gels. A detailed description of the behaviour of gels under measurements is given. Investigations show that to really know the texture both mechanical properties and permeability must be known. Different experiments are reported. They give a rough estimate of the altered layer texture. Results coming from different techniques are compared and in a few cases are used to estimate additional textural information. Finally we put an insight into the nature and consequently to the texture evolution of the layer as the corrosion proceeds. (authors)

Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

Science.gov (United States)

Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

2015-12-01

The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

Corrosion resistance of modified layer on uranium formed by plasma immersion ion implantation

International Nuclear Information System (INIS)

Long Zhong; Liu Kezhao; Bai Bin; Yan Dongxu

2010-01-01

Nitrogen ion was implanted into uranium surface using plasma immersion ion implantation, and the corrosion resistance of modified layer was studied by corrosion experiment. SEM was used to observe variety of samples surface. In atmosphere, the sample surface had not changed during five months. In heat-humid environment, there was dot-corrosion appearing after two months, but it did not influence the integrity of the modified layer. AES was used to study the diffusion of oxygen and nitrogen during hot-humid corrosion, in three months, both of two elements diffused to the substrate, but the diffusion was weak. The structure of modified layer was not changed. Experimental results show that the modified layer formed by plasma immersion ion implantation has good corrosion resistance.

Corrosion resistance of modified layer on uranium formed by plasma immersion ion implantation

Energy Technology Data Exchange (ETDEWEB)

Long Zhong, E-mail: long2001@163.co [China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Liu Kezhao; Bai Bin; Yan Dongxu [China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China)

2010-02-18

Nitrogen ion was implanted into uranium surface using plasma immersion ion implantation, and the corrosion resistance of modified layer was studied by corrosion experiment. SEM was used to observe variety of samples surface. In atmosphere, the sample surface had not changed during five months. In heat-humid environment, there was dot-corrosion appearing after two months, but it did not influence the integrity of the modified layer. AES was used to study the diffusion of oxygen and nitrogen during hot-humid corrosion, in three months, both of two elements diffused to the substrate, but the diffusion was weak. The structure of modified layer was not changed. Experimental results show that the modified layer formed by plasma immersion ion implantation has good corrosion resistance.

Cathodic corrosion protection of steel pipes; Kathodischer Korrosionsschutz von Rohrleitungsstaehlen

Energy Technology Data Exchange (ETDEWEB)

Buechler, Markus [SGK Schweizerische Gesellschaft fuer Korrosionsschutz, Zuerich (Switzerland); Schoeneich, Hanns-Georg [Open Grid Europe, Essen (Germany)

2011-07-01

The cathodic corrosion protection has been proven excellently in the practical use for buried steel pipelines. This is evidenced statistically by a significantly less frequency of loss compared to non-cathodically protected pipelines. Based on thermodynamic considerations, the authors of the contribution under consideration describe the operation of the cathodic corrosion protection and regular adjustment of the electrochemical potential at the interface steel / soil in practical use. Subsequently, the corrosion scenarios are discussed that may occur when an incorrect setting of the potential results from an operation over several decades. This incorrect setting also can be caused by the failure of individual components of the corrosion protection.

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.

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

Science.gov (United States)

Murillo-Gutiérrez, N. V.; Ansart, F.; Bonino, J.-P.; Kunst, S. R.; Malfatti, C. F.

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.

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

International Nuclear Information System (INIS)

Murillo-Gutiérrez, N.V.; Ansart, F.; Bonino, J-P.; Kunst, S.R.; Malfatti, C.F.

2014-01-01

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.

Applications of cathodic protection for the protection of aqueous and soil corrosion of power plant components

International Nuclear Information System (INIS)

Sinha, A.K.; Mitra, A.K.; Bhakta, U.C.; Sanyal, S.K.

2000-01-01

Power plant components exposed to environments such as water and soil are susceptible to severe corrosion. Many times the effect of corrosion in power plant components can be catastrophic. The problem is aggravated for underground pipelines due to additional factors such as large network of pipelines, proximity to earth mat, high voltage transmission lines, corrosive chemicals, inadequate approach etc. Other components such as condenser water boxes, internals of pipelines, clarifier bridge structures, cooling water inlet gates and pipes etc. which are in continuous contact with water, are subjected to severe corrosion. The nature and locations of all such components are at places which are not accessible for routine maintenance and hence they require long term reliable protection against corrosion. Experience has shown that anti-corrosive coatings are inadequate in preventing corrosion and due to their location regular maintenance coatings are also not feasible. Under such circumstances the applications of cathodic protection provides a long term solution the design of cathodic protection, for such applications differs from the commonly employed cathodic protection for cross-country pipelines and submerged structures due to other complexities in the plant region and maintenance of the applied system. The present paper intends to discuss the applications of cathodic protection with suitable anti-corrosive coatings for protection of various power plant components and the specific features of each type of application. (author)

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

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

International Nuclear Information System (INIS)

Yu, Mei; Xue, Bing; Liu, Jianhua; Li, Songmei; Zhang, You

2015-01-01

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 5 Ω·cm 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 coating

Active corrosion protection performance of an epoxy coating applied on the mild steel modified with an eco-friendly sol-gel film impregnated with green corrosion inhibitor loaded nanocontainers

Science.gov (United States)

Izadi, M.; Shahrabi, T.; Ramezanzadeh, B.

2018-05-01

In this study the corrosion resistance, active protection, and cathodic disbonding performance of an epoxy coating were improved through surface modification of steel by a hybrid sol-gel system filled with green corrosion inhibitors loaded nanocontainer as intermediate layer on mild steel substrate. The green inhibitor loaded nanocontainers (GIN) were used to induce active inhibition performance in the protective coating system. The corrosion protection performance of the coated panels was investigated by electrochemical impedance spectroscopy (EIS), salt spray, and cathodic disbonding tests. It was observed that the corrosion inhibition performance of the coated mild steel panels was significantly improved by utilization of active multilayer coating system. The inhibitor release from nanocontainers at the epoxy-silane film/steel interface resulted in the anodic and cathodic reactions restriction, leading to the lower coating delamination from the substrate and corrosion products progress. Also, the active inhibition performance of the coating system was approved by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDS) analysis on the panels with artificial defects. The inhibitive agents were released to the scratch region and blocked the active sites on the metal surface.

Effect of corrosion protective coatings on compressor blades affected by different erosive exposures

International Nuclear Information System (INIS)

Happle, T.W.

1989-01-01

It was the task of this dissertation to examine and to classify the inorganically bonded aluminum coatings with regard to their suitability as a coating for compressor blades for stationary gas turbines and aerojet engines. Industrial aluminum coatings bonded inorganically were used for the tests. Comparative examinations were done with diffusion-deposited aluminum layers as well as with aluminum layers precipitated electrolytically, and with modified inorganically bonded aluminum coatings (with additional TiN protective coating). The examination program was subdivided into two main tasks: Suitability tests and examination of corrosion fatigue. The suitability tests covered corrosion examinations (with salt spray and intermittent immersion tests), electrochemically controlled corrosion assessments (pitting corrosion behavior) and erosion assessments (erosive and abrasive wear tests). Experimental material was mainly the commercial compressor blade steel X20Cr13, and sample tests were carried out with the higher-strength steel X10CrNiMoV12 2 2. For the practical examination of the erosion resistance of the aluminum coatings, it was required to develop an erosion testing method. It was designed as an erosive and abrasive wear testing method with solid-face fluidized bed. The testing method makes it possible to pre-set all relevant quantities which influence the erosive and abrasive wear. (orig./MM) [de

Synthesis, characterization, and corrosion protection properties of poly(N-(methacryloyloxymethyl) benzotriazole-co-methyl methacrylate) on mild steel

Energy Technology Data Exchange (ETDEWEB)

Srikanth, A.P. [Department of Applied Sciences and Humanities, MIT Campus, Anna University, Chennai 600044 (India); Lavanya, A. [Department of Chemistry, CEG Campus, Anna University, Chennai 600025 (India); Nanjundan, S. [Department of Chemistry, CEG Campus, Anna University, Chennai 600025 (India); Rajendran, N. [Department of Applied Sciences and Humanities, MIT Campus, Anna University, Chennai 600044 (India)]. E-mail: nrajendran@annauniv.edu

2006-12-15

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and {sup 13}C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.

Synthesis, characterization, and corrosion protection properties of poly( N-(methacryloyloxymethyl) benzotriazole- co-methyl methacrylate) on mild steel

Science.gov (United States)

Srikanth, A. P.; Lavanya, A.; Nanjundan, S.; Rajendran, N.

2006-12-01

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and 13C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.

Corrosion protection performance of single and dual Plasma Electrolytic Oxidation (PEO) coating for aerospace applications

International Nuclear Information System (INIS)

Madhan Kumar, A.; Kwon, Sun Hwan; Jung, Hwa Chul; Shin, Kwang Seon

2015-01-01

Plasma Electrolytic Oxidation (PEO) coatings are known to be one of the most appropriate method for corrosion protection of magnesium (Mg) alloy. The improvement of PEO coatings and the optimization of their surface aspects are of major importance. In this current work, the influence of dual PEO coating on strip-cast AZ31 Mg alloy substrate has been evaluated with the aim of improving the surface and corrosion protection aspects. For this purpose, AZ31 Mg substrates are subjected to single and dual PEO processing in silicate and phosphate electrolyte under similar condition. Scanning electron microscopy (SEM) analysis confirmed that the number of pores in PEO coating processed in silicate electrolyte is higher than others. X-ray diffraction analysis of PEO coatings showed that the surface coating is mainly comprised of Mg 2 SiO 4 , Mg 3 (PO 4 ) 2 and MgO with different quantity based on PEO processing. Compared with the AZ31 Mg, the corrosion potential (E corr ) of both type PEO coatings was positively shifted about 250–400 mV and the corrosion current density (i corr ) was lowered by 3-4 orders of magnitude as result of adequate corrosion protection to the Mg alloy in 3.5% NaCl solution. All of the observation obviously showed that the dual PEO coating provides better corrosion protection performance than their respective single due to its synergistic beneficial effect. - Highlights: • Influence of dual PEO coating on AZ31 Mg alloy substrate was evaluated. • XRD confirmed formation of thin MgO inner, Mg 3 (PO 4 ) 2 and Mg 2 SiO 4 outer layer. • SEM results showed uniform coating with no cracks and relatively less micro pores. • Micro hardness of dual PEO coatings is higher than single PEO coatings. • Dual coating provides superior corrosion performance due to its synergistic effect

Aqueous corrosion of borosilicate glasses. Nature and properties of alteration layers

International Nuclear Information System (INIS)

Trotignon, Laurent

1990-01-01

This research thesis addresses physical and chemical processes which occur during aqueous corrosion of silicates, and the study of the properties of their interfaces with solutions, and thus issues related to the fate of high activity nuclear wastes which are embedded in a vitreous matrix as the potential release of radionuclides towards the environment then depends on the glass parcel behaviour submitted to chemical attacks which could alter it, notably by aqueous corrosion. The objective is then to model the dissolution of nuclear glass over long periods of time, and to predict the behaviour of radionuclides. The author compared the corrosion and alteration layers of gradually more complex borosilicate glasses, from a ternary sodium borosilicate glass to a simulated nuclear glass (the French reference glass R7T7). Complexity is increased by adding oxides. After some theoretical recalls on the structure and corrosion of borosilicate glasses, the author presents the studied materials, the corrosion experiments, and analytical techniques used to study alteration layers. The mechanism of formation of altered layers is studied based on corrosion experiments performed at 90 C on the whole set of glasses. Alteration layers formed on corroded glasses are studied and compared by using various techniques: electronic microscopy, high energy ion beams, spectroscopy, infrared, photo-electron spectroscopy. Implications for underground storage of nuclear glasses are discussed

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.

Intergranular corrosion protective of austenitic stainless steel chemical equipment

International Nuclear Information System (INIS)

Kuzyukov, A.N.

1994-01-01

A complex of protective measures was developed for each concrete case of intergranular fracture of equipment, i.e.: decrease in the level of strains, surfacing with materials resistant to intergranular fracture under the conditions; permissible correction of process parameters, permitting a shift in corrosion potential towards decrease in the rate of intergranular corrosion. It is shown that even if the eguipment was subject to interfranular corrosion, but the fracture is not of catastrophic character, it proved possible to develop and apply complex methods of protection from the above types of corrosion fracture and to elongate the service life by 5-15 years

Modelling the effects of porous and semi-permeable layers on corrosion processes

International Nuclear Information System (INIS)

King, F.; Kolar, M.; Shoesmith, D.W.

1996-09-01

Porous and semi-permeable layers play a role in many corrosion processes. Porous layers may simply affect the rate of corrosion by affecting the rate of mass transport of reactants and products to and from the corroding surface. Semi-permeable layers can further affect the corrosion process by reacting with products and/or reactants. Reactions in semi-permeable layers include redox processes involving electron transfer, adsorption, ion-exchange and complexation reactions and precipitation/dissolution processes. Examples of porous and semi-permeable layers include non-reactive salt films, precipitate layers consisting of redox-active species in multiple oxidation states (e.g., Fe oxide films), clay and soil layers and biofilms. Examples of these various types of processes will be discussed and modelling techniques developed from studies for the disposal of high-level nuclear waste presented. (author). 48 refs., 1 tab., 12 figs

Microstructure characteristic and excellent corrosion protection properties of sealed Zn-TiO{sub 2} composite coating for sintered NdFeB magnet

Energy Technology Data Exchange (ETDEWEB)

Yang Xiaokui [School of Materials Science and Engineering, Southwest University, Chongqing 400715 (China); Li Qing, E-mail: liqingd@swu.edu.c [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang Shiyan; Liu Fang; Wang Shaoyin; Zhang Haixiao [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

2010-04-09

In this paper, a protective sealed Zn-TiO{sub 2} composite coating (SCC) was prepared on sintered NdFeB magnet by electrodeposition and sol-gel combined technique. For a comparison, unsealed Zn-TiO{sub 2} composite coating (UCC) was also studied. The surface morphologies of composite coating were studied using scanning electron microscope (SEM). The microstructure of composite coatings and structure of sealing layer were studied by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum, respectively. The anticorrosive properties of composite coatings in neutral 3.5 wt.% NaCl solutions were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. The results of corrosion tests showed that due to the blocking effect of sealing layer, SCC could suppress the corrosion process by holding back the transfer or diffusion of corrosive medium, and therefore showed the excellent corrosion protection properties for sintered NdFeB magnet.

Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

International Nuclear Information System (INIS)

Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

2015-01-01

The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO 2 implanted AISI 304 – examined for different implantation and annealing parameters – is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 10 16 cm −2 (Ti + ) and 1 × 10 17 cm −2 (O + ) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 10 15 cm −2 (Ti + ) and 1 × 10 16 cm −2 (O + ). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO 2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

Hybrid epoxy–silane coatings for improved corrosion protection of Mg alloy

International Nuclear Information System (INIS)

Brusciotti, Fabiola; Snihirova, Darya V.; Xue, Huibin; Montemor, M. Fatima; Lamaka, Svetlana V.; Ferreira, Mario G.S.

2013-01-01

Highlights: ► Hybrid epoxy–silane coatings for corrosion protection of Mg alloy AZ31. ► Electrochemical impedance spectroscopy to study the corrosion behavior. ► Very good corrosion protection after 1 month immersion in 0.05 M NaCl. ► Surface and chemical characterization to understand corrosion processes. ► Influence of organic structure in coatings corrosion performance. - Abstract: New hybrid epoxy–silane coatings, with added functionalities for improved performance and durability, were designed to increase the corrosion protection of magnesium alloys. The corrosion behavior of the coated AZ31 was studied through electrochemical impedance spectroscopy (EIS) in 0.05 M NaCl. The morphology and surface chemistry of the samples were also investigated through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) before and after immersion in the electrolyte. The new hybrid silane coatings showed a high resistance to corrosion that persisted throughout one-month immersion in a pH-neutral NaCl solution.

Corrosion behaviour of layers obtained by nitrogen implantation into boron films deposited onto iron substrates

International Nuclear Information System (INIS)

Marchetti, F.; Fedrizzi, L.; Giacomozzi, F.; Guzman, L.; Borgese, A.

1985-01-01

The electrochemical behaviour and corrosion resistance of boron films deposited onto Armco iron after bombardment with 100 keV N + ions were determined in various test solutions. The changes in the electrochemical parameters give evidence of lower anodic dissolution rates for the treated samples. Scanning electron microscopy and Auger analysis of the corroded surfaces confirm the presence of protective layers. (Auth.)

Restraint deformation and corrosion protection of gold deposited aluminum mirrors for cold optics of mid-infrared instruments

Science.gov (United States)

Uchiyama, Mizuho; Miyata, Takashi; Sako, Shigeyuki; Kamizuka, Takafumi; Nakamura, Tomohiko; Asano, Kentaro; Okada, Kazushi; Onaka, Takashi; Sakon, Itsuki; Kataza, Hirokazu; Sarugaku, Yuki; Kirino, Okiharu; Nakagawa, Hiroyuki; Okada, Norio; Mitsui, Kenji

2014-07-01

We report the restraint deformation and the corrosion protection of gold deposited aluminum mirrors for mid-infrared instruments. To evaluate the deformation of the aluminum mirrors by thermal shrinkage, monitoring measurement of the surface of a mirror has been carried out in the cooling cycles from the room temperature to 100 K. The result showed that the effect of the deformation was reduced to one fourth if the mirror was screwed with spring washers. We have explored an effective way to prevent the mirror from being galvanically corroded. A number of samples have been prepared by changing the coating conditions, such as inserting an insulation layer, making a multi-layer and overcoating water blocking layer, or carrying out precision cleaning before coating. Precision cleaning before the deposition and protecting coat with SiO over the gold layer seemed to be effective in blocking corrosion of the aluminum. The SiO over-coated mirror has survived the cooling test for the mid-infrared use and approximately 1 percent decrease in the reflectance has been detected at 6-25 microns compared to gold deposited mirror without coating.

Corrosion resistance and protection mechanism of hot-dip Zn-Al-Mg alloy coated steel sheet under accelerated corrosion environment; Yoyu Zn-Al-Mg kei gokin mekki koban no sokushin fushoku kankyoka ni okeru taishokusei toi boshoku kiko

Energy Technology Data Exchange (ETDEWEB)

Komatsu, A.; Izutani, H.; Tsujimura, T.; Ando, A.; Kittaka, T. [NKK Corp., Tokyo (Japan)

2000-08-01

Corrosion behavior of hot-dip Zn-6%Al 0-3%Mg alloy coated steel sheets in cyclic corrosion test (CCT) has been investigated. The corrosion resistance was improved with increasing Mg content in the coating layer, and the highest corrosion resistance was observed at 3% Mg. In Zn-6%Al-3%Mg alloy coated steel sheet, the formations of zinc carbonate hydroxide and zinc oxide were suppressed for longer duration compared with Zn-0.2%Al and Zn-4.5%Al-0.l%Mg alloy coated steel sheets. As a result, zinc chloride hydroxide existed stable on the surface of the coating layer. From the polarization behaviors in 5% NaCl aqueous solution after CCT, it was found that the corrosion current density of Zn-6%At-3%Mg alloy coated steel sheet was much smaller than those of Zn-0.2%Al and Zn-4.5%Al-0.1%Mg alloy coated steel sheets. As zinc carbonate hydroxide and zinc oxide had poor adhesion to the coating layer and had porous structures, these corrosion products were considered to have little protective action for the coating layer. Therefore, it was concluded that Mg suppressed the formation of such nonprotective corrosion products. resulting in the remarkable improvement of corrosion resistance. (author)

Niobium–niobium oxide multilayered coatings for corrosion protection of proton-irradiated liquid water targets for ["1"8F] production

International Nuclear Information System (INIS)

Skliarova, Hanna; Renzelli, Marco; Azzolini, Oscar; Felicis, Daniele de; Bemporad, Edoardo; Johnson, Richard R.; Palmieri, Vincenzo

2015-01-01

Chemically inert coatings on Havar"® entrance foils of the targets for ["1"8F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar"®. During current investigation, magnetron sputtered niobium and niobium oxide were chosen as the candidates for protective coatings because of their superior chemical resistance. Aluminated quartz substrates allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modeling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. As far as niobium coatings obtained by magnetron sputtering are columnar, the grain boundaries provide a fast diffusion path for active species of corrosive media to penetrate and to corrode the substrate. Amorphous niobium oxide films obtained by reactive magnetron sputtering showed superior barrier properties according to the corrosion tests performed. In order to prevent degrading of brittle niobium oxide at high pressures, multilayers combining high ductility of niobium with superior diffusion barrier efficiency of niobium oxide were proposed. The intercalation of niobium oxide interlayers was proved to interrupt the columnar grain growth of niobium during sputtering, resulting in improved diffusion barrier efficiency of obtained multilayers. The thin layer multilayer coating architecture with 70 nm bi-layer thickness was found preferential because of higher thermal stability. - Highlights: • Diffusion barrier efficiency of niobium, niobium oxide and their multilayers was studied. • The intercalation of niobium oxide layers interrupted the columnar grain growth of niobium. • The bilayer architectures influenced the stability of the multilayer coatings. • The thin layer multilayer coating with 70 nm double-layer was found superior.

Niobium–niobium oxide multilayered coatings for corrosion protection of proton-irradiated liquid water 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); Renzelli, Marco, E-mail: marco.renzelli@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (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); Felicis, Daniele de, E-mail: daniele.defelicis@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (Italy); Bemporad, Edoardo, E-mail: edoardo.bemporad@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (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)

2015-09-30

Chemically inert coatings on Havar{sup ®} entrance foils of the targets for [{sup 18}F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar{sup ®}. During current investigation, magnetron sputtered niobium and niobium oxide were chosen as the candidates for protective coatings because of their superior chemical resistance. Aluminated quartz substrates allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modeling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. As far as niobium coatings obtained by magnetron sputtering are columnar, the grain boundaries provide a fast diffusion path for active species of corrosive media to penetrate and to corrode the substrate. Amorphous niobium oxide films obtained by reactive magnetron sputtering showed superior barrier properties according to the corrosion tests performed. In order to prevent degrading of brittle niobium oxide at high pressures, multilayers combining high ductility of niobium with superior diffusion barrier efficiency of niobium oxide were proposed. The intercalation of niobium oxide interlayers was proved to interrupt the columnar grain growth of niobium during sputtering, resulting in improved diffusion barrier efficiency of obtained multilayers. The thin layer multilayer coating architecture with 70 nm bi-layer thickness was found preferential because of higher thermal stability. - Highlights: • Diffusion barrier efficiency of niobium, niobium oxide and their multilayers was studied. • The intercalation of niobium oxide layers interrupted the columnar grain growth of niobium. • The bilayer architectures influenced the stability of the multilayer coatings. • The thin layer multilayer coating with 70 nm double-layer was found superior.

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.

Effects of porosity in a model of corrosion and passive layer growth

Directory of Open Access Journals (Sweden)

F.D.A. Aarão Reis

2017-12-01

Full Text Available We introduce a stochastic lattice model to investigate the effects of pore formation in a passive layer grown with products of metal corrosion. It considers that an anionic species diffuses across that layer and reacts at the corrosion front (metal-oxide interface, producing a random distribution of compact regions and large pores, respectively represented by O (oxide and P (pore sites. O sites are assumed to have very small pores, so that the fraction Φ of P sites is an estimate of the porosity, and the ratio between anion diffusion coefficients in those regions is D_r0 and D_r≪1, significant changes are observed in passive layer growth and corrosion front roughness. For small Φ, a slowdown of the growth rate is observed, which is interpreted as a consequence of the confinement of anions in isolated pores for long times. However, the presence of large pores near the corrosion front increases the frequency of reactions at those regions, which leads to an increase in the roughness of that front. This model may be a first step to represent defects in a passive layer which favor pitting corrosion.

Influence of cold worked layer on susceptibility to stress corrosion of duplex stainless steel

International Nuclear Information System (INIS)

Labanowski, J.; Ossowska, A.; Cwiek, J.

2001-01-01

Stress corrosion cracking resistance of cold worked layers on duplex stainless steel was investigated. The surface layers were performed through burnishing treatment. Corrosion tests were performed with the use of Slow Strain Rate Test technique in boiling 35% MgCl 2 solution. It has been shown that burnishing treatment increases corrosion resistance of steel. The factor that improves stress corrosion cracking resistance is crack incubation time. (author)

Ni-P/Zn-Ni compositionally modulated multilayer coatings - Part 2: Corrosion and protection mechanisms

Science.gov (United States)

Bahadormanesh, Behrouz; Ghorbani, Mohammad

2018-06-01

The Ni-P/Zn-Ni compositionally modulated multilayer coatings CMMCs were electrodeposited from a single bath by switching the deposition current density. The corrosion resistance of the deposits was studied and compared with that of monolayers of Ni-P and Zn-Ni alloys via Tafel polarization, EIS and salt spray tests. Characterization of corrosion products by means of EDS and XRD revealed more details from the corrosion mechanism of the monolayers and multilayers. The corrosion current density of Ni-P/Zn-Ni CMMCs were around one tenth of Zn-Ni monolayer. The CMMC with incomplete layers performed lower polarization resistance and higher corrosion current density compared to the CMMC with complete layers. The electrical circuit that was proposed for modeling the corrosion process based on the EIS spectrum, proved that layering reduces the porosity and consequently improves the barrier properties. Although, layering of Zn-Ni layers with Ni-P deposits increased the time to red rust in salt spray test, the time for white rust formation decreased. The corrosion mechanism of both Zn-Ni and Ni-P (containing small amount of Zn) was preferential dissolution of Zn and the corrosion products were comprised of mainly Zn hydroxychloride and Zn hydroxycarbonate. Also, Ni and P did not take part in the corrosion products. Based on the electrochemical character of the layers and the morphology of the corroded surface, the corrosion mechanism of multilayers was discussed.

Corrosion monitoring of iron, protected by an organic coating, with the aid of impedance measurements

International Nuclear Information System (INIS)

Hubrecht, J.; Piens, M.; Vereecken, J.

1984-01-01

The ac impedance measurement has proved to be a useful electrochemical technique for mainly qualitative studies of electrochemical and corrosion systems. Even for complicated systems such as coated metals in corrosive environments this technique has been used with success. The system chosen for the present study is an ARMCO iron plate, coated with a SrCrO 4 -pigmented styrene acrylic polymer, and immersed for several weeks in an aqueous NaCl solution. Impedance measurements analyze a system under test into its constituting phenomena. The dependence of system parameters on coating layer thickness, NaCl concentration, and pigmentation of the coating during the immersion time provides insight into the corrosion and protection mechanisms at the coating/metal interface, besides the behavior of the coating itself

Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

Science.gov (United States)

Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

2015-10-13

Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

Enhancement of the corrosion protection of electroless Ni–P coating by deposition of sonosynthesized ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sharifalhoseini, Zahra [Sonochemical Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of); Entezari, Mohammad H., E-mail: entezari@um.ac.ir [Sonochemical Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of); Environmental Chemistry Research Center, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, 91779 Mashhad (Iran, Islamic Republic of)

2015-10-01

Graphical abstract: Enhancement of the corrosion protection of electroless Ni–P layer by ZnO nanoparticles deposition and the comparison with the classical and sonochemical Ni–P coatings. - Highlights: • Unique effects of ultrasound were investigated on the anticorrosive performance of electroless Ni–P coating. • Sonoynthesis of ZnO NPs and its deposition were performed on the surface of Ni–P coating. • ZnO as an anticorrosive has a critical role in the multifunctional surfaces. • Electrochemical properties of all fabricated samples were compared with each other. - Abstract: Ni–P coatings were deposited through electroless nickel plating in the presence and absence of ultrasound. The simultaneous synthesis of ZnO nanoparticle and its deposition under ultrasound were also carried out on the surface of Ni–P layer prepared by the classical method. The morphology of the surfaces and the chemical composition were determined by scanning electron microscopy(SEM) and energy dispersive spectroscopy (EDS), respectively. Electrochemical techniques were applied for the corrosion behavior studies. The Ni–P layer deposited by ultrasound showed a higher anticorrosive property than the layer deposited by the classical method. The ZnO nanoparticles deposited on the surface of Ni–P layer significantly improved the corrosion resistance.

Positron annihilation in corrosion protective polymeric coatings. Pt. 2

International Nuclear Information System (INIS)

Szeles, C.; Vertes, A.; White, M.L.; Leidheiser, H. Jr.; Lehigh Univ., Bethlehem, PA

1988-01-01

Positron annihilation was studied in four commercial polymeric coatings on iron. Positron lifetime measurements were performed before and after exposure of the coatings to boiling water for 1 h. A correlation was observed between the effect of water exposure on the lifetime spectra and the protective properties of the coatings when exposed to 0.1M sulfuric acid at 60 0 C for 1010 h. The coatings that provided good corrosion protection in the acid showed minor changes in the positron lifetime spectra upon exposure to water. The spectra of coatings that showed poor corrosion protection in the acid showed minor changes in the positron lifetime spectra upon exposure to water. The spectra of coatings that showed poor corrosion protection, on the other hand, exhibited considerable changes in the positron lifetime spectra upon exposure to water. (orig.)

Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

Energy Technology Data Exchange (ETDEWEB)

Hartwig, A.; Decker, M.; Klein, O.; Karl, H., E-mail: helmut.karl@physik.uni-augsburg.de

2015-12-15

The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO{sub 2} implanted AISI 304 – examined for different implantation and annealing parameters – is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 10{sup 16} cm{sup −2} (Ti{sup +}) and 1 × 10{sup 17} cm{sup −2} (O{sup +}) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 10{sup 15} cm{sup −2} (Ti{sup +}) and 1 × 10{sup 16} cm{sup −2} (O{sup +}). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO{sub 2} inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

Corrosion protection of reusable surgical instruments.

Science.gov (United States)

Shah, Sadiq; Bernardo, Mildred

2002-01-01

To understand the corrosion properties of surgical scissors, 416 stainless steel disks and custom electrodes were used as simulated surfaces under various conditions. These simulated surfaces were exposed to tap water and 400-ppm synthetic hard water as Ca2CO3 under different conditions. The samples were evaluated by various techniques for corrosion potential and the impact of environmental conditions on the integrity of the passive film. The electrodes were used to monitor the corrosion behavior by potentiodynamic polarization technique in water both in the presence and absence of a cleaning product. The surface topography of the 416 stainless steel disks was characterized by visual observations and scanning electron microscopy (SEM), and the surface chemistry of the passive film on the surface of the scissors was characterized by x-ray photoelectron spectroscopy (XPS). The results suggest that surgical instruments made from 416 stainless steel are not susceptible to uniform corrosion; however, they do undergo localized corrosion. The use of suitable cleaning products can offer protection against localized corrosion during the cleaning step. More importantly, the use of potentiodynamic polarization techniques allowed for a quick and convenient approach to evaluate the corrosion properties of surgical instruments under a variety of simulated-use environmental conditions.

Thin polycrystalline diamond films protecting zirconium alloys surfaces: From technology to layer analysis and application in nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Ashcheulov, P. [Institute of Physics, Academy of Sciences Czech Republic v.v.i, Na Slovance 2, CZ-182 21, Prague 8 (Czech Republic); Škoda, R.; Škarohlíd, J. [Czech Technical University in Prague, Faculty of Mechanical Engineering, Technická 4, Prague 6, CZ-160 07 (Czech Republic); Taylor, A.; Fekete, L.; Fendrych, F. [Institute of Physics, Academy of Sciences Czech Republic v.v.i, Na Slovance 2, CZ-182 21, Prague 8 (Czech Republic); Vega, R.; Shao, L. [Texas A& M University, Department of Nuclear Engineering TAMU-3133, College Station, TX TX 77843 (United States); Kalvoda, L.; Vratislav, S. [Faculty of Nuclear Science and Physical Engineering, Czech Technical University in Prague, Brehova 7, CZ-115 19, Prague 1 (Czech Republic); Cháb, V.; Horáková, K.; Kůsová, K.; Klimša, L.; Kopeček, J. [Institute of Physics, Academy of Sciences Czech Republic v.v.i, Na Slovance 2, CZ-182 21, Prague 8 (Czech Republic); Sajdl, P.; Macák, J. [University of Chemistry and Technology, Power Engineering Department, Technická 3, Prague 6, CZ-166 28 (Czech Republic); Johnson, S. [Nuclear Fuel Division, Westinghouse Electric Company, 5801 Bluff Road, Hopkins, SC 29209 (United States); Kratochvílová, I., E-mail: krat@fzu.cz [Institute of Physics, Academy of Sciences Czech Republic v.v.i, Na Slovance 2, CZ-182 21, Prague 8 (Czech Republic); Faculty of Nuclear Science and Physical Engineering, Czech Technical University in Prague, Brehova 7, CZ-115 19, Prague 1 (Czech Republic)

2015-12-30

Graphical abstract: - Highlights: • In this work we showed that films prepared by MW-LA-PECVD technology can be used as anticorrosion protective layer for Zircaloy2 nuclear fuel claddings at elevated temperatures (950 °C) when α phase of zirconium changes to β phase (more opened for oxygen/hydrogen diffusion). Quality of PCD films was examined by Raman spectroscopy, XPS, SEM, AFM and SIMS analysis. • The polycrystalline diamond films were of high quality - without defects and contaminations. After hot steam oxidation (950 °C) a high level of structural integrity of PCD layer was observed. Both sp{sup 2} and sp{sup 3} C phases were present in the protective PCD layer. Higher resistance and a lower degree of impedance dispersion was found in the hot steam oxidized PCD coated Zircaloy2 samples, which may suggest better protection of the Zircaloy2 surface. The PCD layer blocks the hydrogen diffusion into the Zircaloy2 surface thus protecting the material from degradation. • Hot steam oxidation tests confirmed that PCD coated Zircaloy2 surfaces were effectively protected against corrosion. Presented results demonstrate that the PCD anticorrosion protection can significantly prolong service life of Zircaloy2 nuclear fuel claddings in nuclear reactors even at elevated temperatures. - Abstract: Zirconium alloys can be effectively protected against corrosion by polycrystalline diamond (PCD) layers grown in microwave plasma enhanced linear antenna chemical vapor deposition apparatus. Standard and hot steam oxidized PCD layers grown on Zircaloy2 surfaces were examined and the specific impact of polycrystalline Zr substrate surface on PCD layer properties was investigated. It was found that the presence of the PCD coating blocks hydrogen diffusion into the Zircaloy2 surface and protects Zircaloy2 material from degradation. PCD anticorrosion protection of Zircaloy2 can significantly prolong life of Zircaloy2 material in nuclear reactors even at temperatures above Zr

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

International Nuclear Information System (INIS)

Behrens, Sabine; Hassel, Thomas; Bach, Friedrich-Wilhelm

2012-01-01

The corrosion protection of the internal space of thick-walled interim and permanent storage facility components, such as Castor 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 μm 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 demonstration

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment.

Science.gov (United States)

Boinovich, Ludmila B; Emelyanenko, Alexandre M; Modestov, Alexander D; Domantovsky, Alexandr G; Emelyanenko, Kirill A

2015-09-02

We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

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

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.

Method for inhibiting corrosion of nickel-containing alloys

Science.gov (United States)

DeVan, J.H.; Selle, J.E.

Nickel-containing alloys are protected against corrosion by contacting the alloy with a molten alkali metal having dissolved therein aluminum, silicon or manganese to cause the formation of a corrosion-resistant intermetallic layer. Components can be protected by applying the coating after an apparatus is assembled.

Corrosion of aluminum components and remedial measures

International Nuclear Information System (INIS)

Sheikh, S.T.; Khalique, A.; Malik, F.A.

2006-01-01

Aluminum has versatile physical properties, mechanical strength, corrosion resistance, and is used in special applications like aerospace, automobiles and other strategic industries. The outdoor exposed structural components of aluminum have very good corrosion resistance due to the thick oxide layer (0.2 -0.4 micro). This study involves the corrosion of aluminum based components, though aluminum is protected by an oxide layer but due to extreme weather and environmental conditions the oxide layer was damaged. The corroded product was removed, pits or cavities formed due to the material removal were filled with epoxy resins and acrylic-based compounds containing fibreglass as reinforcement. Optimum results were obtained with epoxy resins incorporated with 5% glass fibers. The inner surface of the components was provided further protection with a cellulose nitrate compound. (author)

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.

Molybdate Coatings for Protecting Aluminum Against Corrosion

Science.gov (United States)

Calle, Luz Marina; MacDowell, Louis G.

2005-01-01

Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

Plasma source ion implantation process for corrosion protection of 6061 aluminum

International Nuclear Information System (INIS)

Zhang, L.; Booske, J.H.; Shohet, J.L.; Jacobs, J.R.; Bernardini, A.J.

1995-01-01

This paper describes results of an investigation of the feasibility of using nitrogen plasma source ion implantation (PSII) treatment to improve corrosion resistance of 6061 aluminum to salt water. Flat Al samples were implanted with various doses of nitrogen. The surface microstructures and profiles of Al and N in the flat samples were examined using transmission electron microscopy (TEM), scanning Auger microprobe, x-ray diffraction. Corrosion properties of the samples and the components were evaluated using both a 500 hour salt spray field test and a laboratory electrochemical corrosion system. The tested samples were then analyzed by scanning electron microscopy. Corrosion measurements have demonstrated that PSII can significantly improve the pitting resistance of 6061 aluminum. By correlating the analytical results with the corrosion test results, it has been verified that the improved corrosion resistance in PSII-treated coupons is due to the formation of a continuous AlN layer. It was also identified that the formation of a continuous AlN layer. It was also identified that the formation of a continuous AlN layer is mainly determined by the bias voltage and the total integrated implantation dose, and relatively insensitive to factors such as the plasma source, pulse length, or frequency

Element distribution in the corrosion layer and cytotoxicity of alloy Mg-10Dy during in vitro biodegradation.

Science.gov (United States)

Yang, Lei; Hort, Norbert; Laipple, Daniel; Höche, Daniel; Huang, Yuanding; Kainer, Karl Ulrich; Willumeit, Regine; Feyerabend, Frank

2013-11-01

The present work investigates the corrosion behaviour, the element distribution in the corrosion layer and the cytocompatibility of alloy Mg-10Dy. The corrosion experiments were performed in a cell culture medium (CCM) under cell culture conditions close to the in vivo environment. The element distribution on the surface as well as in cross-sections of the corrosion layer was investigated using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. The cytocompatibility of alloy Mg-10Dy with primary human osteoblasts was evaluated by MTT, cell adhesion and live/dead staining tests. The results show that the corrosion layer was enriched in Dy, while the P and Ca content gradually decreased from the surface to the bottom of the corrosion layer. In addition, large amounts of MgCO3·3H2O formed in the corrosion layer after 28 days immersion. Both extracts and the Dy-enriched corrosion layer of alloy Mg-10Dy showed no cytotoxicity to primary human osteoblasts. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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.

Ozone Layer Protection

Science.gov (United States)

... and Research Centers Contact Us Share Ozone Layer Protection The stratospheric ozone layer is Earth’s “sunscreen” – protecting ... GreenChill Partnership Responsible Appliance Disposal (RAD) Program Ozone Protection vs. Ozone Pollution This website addresses stratospheric ozone ...

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.

Mechanism of Corrosion by Naphthenic Acids and Organosulfur Compounds at High Temperatures

Science.gov (United States)

Jin, Peng

Due to the law of supply and demand, the last decade has witnessed a skyrocketing in the price of light sweet crude oil. Therefore, refineries are increasingly interested in "opportunity crudes", characterized by their discounted price and relative ease of procurement. However, the attractive economics of opportunity crudes come with the disadvantage of high acid/organosulfur compound content, which could lead to corrosion and even failure of facilities in refineries. However, it is generally accepted that organosulfur compounds may form protective iron sulfide layers on the metal surface and decrease the corrosion rate. Therefore, it is necessary to investigate the corrosive property of crudes at high temperatures, the mechanism of corrosion by acids (naphthenic acids) in the presence of organosulfur compounds, and methods to mitigate its corrosive effect. In 2004, an industrial project was initiated at the Institute for Corrosion and Multiphase Technology to investigate the corrosion by naphthenic acids and organosulfur compounds. In this project, for each experiment there were two experimentation phases: pretreatment and challenge. In the first pretreatment phase, a stirred autoclave was filled with a real crude oil fraction or model oil of different acidity and organosulfur compound concentration. Then, the stirred autoclave was heated to high temperatures to examine the corrosivity of the oil to different materials (specimens made from CS and 5% Cr containing steel were used). During the pretreatment, corrosion product layers were formed on the metal surface. In the second challenge phase, the steel specimens pretreated in the first phase were inserted into a rotating cylinder autoclave, called High Velocity Rig (HVR). The HVR was fed with a high-temperature oil solution of naphthenic acids to attack the iron sulfide layers. Based on the difference of specimen weight loss between the two steps, the net corrosion rate could be calculated and the protectiveness

''Ftorlon'' coats for corrosion protection of electrodialysis units

International Nuclear Information System (INIS)

Shigorina, I.I.; Egorov, B.N.; Kalinkin, A.V.; Kapustin, A.F.; Shigorin, V.G.; Smirnova, N.M.

1983-01-01

This article examines the coats for protecting components of electrodialysis units (housing, frames, etc.) with respect to chemical stability, electric insulation properties, and with reference to atomic power station (APS) decontamination and radiation resistance. The physicomechanical properties of the coats were investigated by the standard methods. The radiation resistance of the coats was judged from the change in their physicomechanical and protective properties in corrosive media by placing the coat samples in the gamma-field of a Co 60 source at an intensity of 3.5-4 Gr/sec. Recommends the coat SP-CSPE-31 based on chlorosulfonated polythylene (TU-11-118-74) for corrosion protection of the EDU bulky equipment designed for desalination of sea water for industrial and household purposes

Study on the hot corrosion behavior of a cast Ni-base superalloy

Energy Technology Data Exchange (ETDEWEB)

Wang, W.; Guo, J.T.; Zhang, J.; Yuan, C.; Zhou, L.Z.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

2010-07-01

Hot corrosion behavior of Nickel-base cast superalloy K447 in 90% Na{sub 2}SO{sub 4} + 10% NaCl melting salt at 850 C and 900 C was studied. The hot corrosion kinetic of the alloy follows parabolic rate law under the experimental conditions. The external layer is mainly Cr{sub 2}O{sub 3} scale which is protective to the alloy, the intermediate layer is the Ti-rich phase, and the internal layer is mainly the international oxides and sulfides. With increased corrosion time and temperature, the oxide scales are gradually dissolved in the molten salt and then precipitate as a thick and non-protective scale. Chlorides cause the formation of volatile species, which makes the oxide scale disintegrate and break off. The corrosion kinetics and morphology examinations tend to support the basic dissolution model for hot corrosion mechanisms. (orig.)

GCR dismantling: corrosion of vessel internals during decay storage

International Nuclear Information System (INIS)

Gras, J.M.

1991-06-01

Gas-cooled reactor decommissioning confronts EDF with the problem of the corrosion resistance of vessel internals over a decay storage period fixed at 50 years. The layer of magnetite previously formed in the C0 2 should protect structural steelwork from atmospheric corrosion. In any case, estimated steel corrosion after 50 years may be put at below or equal to 0.1 mm and the corresponding swelling induced by corrosion products at 0.2 mm. There should be no risk of hydrogen embrittlement or stress corrosion cracking of threaded fasteners. Corrosion tests aimed at providing further insight into the effects of the magnetite layer and a program for the surveillance of post-decommissioning structural corrosion should nevertheless be envisaged

A study on the corrosion test of equipment material handling hot molten salt

International Nuclear Information System (INIS)

Ro, Seung Gy; Jeong, M.S.; Hong, S.S.; Cho, S.H.; Shin, Y.J.; Park, H.S.; Zhang, J.S.

1999-02-01

On this technical report, corrosion behavior of austenitic stainless steels of SUS 316L and SUS 304L in molten salt of LiCl-Li 2 O has been investigated in the temperature range of 650 - 850 dg C. Corrosion products of SUS 316L in molten salt consisted of two layers, an outer layer of LiCrO 2 and inner layer of Cr 2 O 3 .The corrosion layer was uniform in molten salt of LiCl, but the intergranular corrosion occurred in addition to the uniform corrosion in mixed molten salt of LiCl-Li 2 O. The corrosion rate increased slowly with the increase of temperature up to 750 dg C, but above 750 dg C rapid increase in corrosion rate observed. SUS 316L stainless steel showed slower corrosion rate and higher activation energy for corrosion than SUS 304L, exhibiting higher corrosion resistance in the molten salt. In heat-resistant alloy, dense protective oxide scale of LiCrO 2 was formed in molten salt of LiCl. Whereas in mixed molten salt of LiCl-Li 2 O, porous non-protective scale of Li(Cr, Ni, Fe)O 2 was formed. (Author). 44 refs., 4 tabs., 16 figs

Corrosion behavior of boride layers evaluated by the EIS technique

Energy Technology Data Exchange (ETDEWEB)

Campos, I. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico)], E-mail: icampos@ipn.mx; Palomar-Pardave, M. [Universidad Autonoma Metropolitana-Azcapotzalco, Materials Department, Avenue San Pablo 180 Col. Reynosa Tamaulipas, Mexico D.F. 02200 (Mexico); Amador, A. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico); VillaVelazquez, C. [Instituto Politecnico Nacional. SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F. 07738 (Mexico); Hadad, J. [Tecnologico de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222 Col. Ejidos de Huipulco, Mexico D.F. 14380 (Mexico)

2007-09-30

The corrosion behavior of boride layers at the AISI 304 steel surface is evaluated in the present study. Electrochemical impedance spectroscopy (EIS) technique was used for the evaluation of the polarization resistance at the steel surface, with the aid of AUTOLAB potentiostat. Samples were treated with boron paste thickness of 4 and 5 mm, in the range of temperatures 1123 {<=} T {<=} 1273 K and exposed time of 4 and 6 h. The electrochemical technique employed 10 mV AC with a frequency scan range from 8 kHz to 3 mHz in deaerated 0.1 M NaCl solution. Nyquist diagrams show that the highest values of corrosion resistance are present in the samples borided at the temperature of 1273 K, with treatment time of 4 h and 4 mm of boron paste thickness. The values of corrosion resistance on borided steels are compared with the porosity exhibited in the layers.

Wire-Arc-Sprayed Aluminum Protects Steel Against Corrosion

Science.gov (United States)

Zimmerman, Frank R.; Poorman, Richard; Sanders, Heather L.; Mckechnie, Timothy N.; Bonds, James W., Jr.; Daniel, Ronald L., Jr.

1995-01-01

Aluminum coatings wire-arc sprayed onto steel substrates found effective in protecting substrates against corrosion. Coatings also satisfy stringent requirements for adhesion and flexibility, both at room temperature and at temperatures as low as liquid hydrogen. Developed as alternatives to corrosion-inhibiting primers and paints required by law to be phased out because they contain and emit such toxic substances as chromium and volatile organic compounds.

Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

International Nuclear Information System (INIS)

Wu Liankui; Hu Jiming; Zhang Jianqing

2012-01-01

Highlights: ► Metallic zinc is doped into organosilane films by one-step electrodeposition. ► The composite films exhibit the improved corrosion resistance of mild steels. ► Zinc-doping provides additional cathodic protection to the mild steels. - Abstract: Organosilane/zinc composite films are prepared by one-step electrodeposition onto cold-rolled steels for corrosion protection. Electrochemical impedance spectroscopy measurement, bulk solution immersion and wet heat tests all show that the composite films have improved corrosion performance. X-ray photoelectron spectroscopy measurement suggests the successful encapsulation of metallic zinc. The embedding of metallic zinc results in negative shift in open-circuit potential of the film-covered electrodes. Such cathodic protection effect given by the metallic zinc provides the improved corrosion resistance of the composite films.

Solution-deposited F:SnO₂/TiO₂ as a base-stable protective layer and antireflective coating for microtextured buried-junction H₂-evolving Si photocathodes.

Science.gov (United States)

Kast, Matthew G; Enman, Lisa J; Gurnon, Nicholas J; Nadarajah, Athavan; Boettcher, Shannon W

2014-12-24

Protecting Si photocathodes from corrosion is important for developing tandem water-splitting devices operating in basic media. We show that textured commercial Si-pn(+) photovoltaics protected by solution-processed semiconducting/conducting oxides (plausibly suitable for scalable manufacturing) and coupled to thin layers of Ir yield high-performance H2-evolving photocathodes in base. They also serve as excellent test structures to understand corrosion mechanisms and optimize interfacial electrical contacts between various functional layers. Solution-deposited TiO2 protects Si-pn(+) junctions from corrosion for ∼24 h in base, whereas junctions protected by F:SnO2 fail after only 1 h of electrochemical cycling. Interface layers consisting of Ti metal and/or the highly doped F:SnO2 between the Si and TiO2 reduce Si-emitter/oxide/catalyst contact resistance and thus increase fill factor and efficiency. Controlling the oxide thickness led to record photocurrents near 35 mA cm(-2) at 0 V vs RHE and photocathode efficiencies up to 10.9% in the best cells. Degradation, however, was not completely suppressed. We demonstrate that performance degrades by two mechanisms, (1) deposition of impurities onto the thin catalyst layers, even from high-purity base, and (2) catastrophic failure via pinholes in the oxide layers after several days of operation. These results provide insight into the design of hydrogen-evolving photoelectrodes in basic conditions, and highlight challenges.

Mechanical properties of layers of corrosion products at steel / concrete interface

International Nuclear Information System (INIS)

Dehoux, Anita

2012-01-01

To take account of the development of corrosion products layers in residual lifetime calculations of reinforced concrete structures requires a good knowledge of the mechanical properties of these products. Our study aims to determine the mechanical properties of layers of corrosion products. The approach consists of an identification of the microstructure properties complemented by homogenization calculations to calculate a mesoscopic behavior in linear elasticity of layers of corrosion products. The study includes a series of experimental campaigns at the microscopic scale. Vickers micro indentation tests analyzed by a Gaussian mixture model approach allowed the acquisition of hardness and elastic moduli at the microscale. An identification of the microstructure products is performed by Raman microspectrometry. The microstructure's characterization brings valuable information for homogenization calculations. The first approach has consisted of calculations of random media homogenization by self-consistent and generalized self-consistent schemes. In the second approach, effective modulus calculations were performed using numerical microstructures resulting from 2D images taken with an optical microscope. The corpus is composed of samples of different ages and origins, their microstructures were compared. (author) [fr

Corrosion inhibition performance of imidazolium ionic liquids and their influence on surface ferrous carbonate layer formation

Science.gov (United States)

Yang, Dongrui

Corrosion inhibitors as effective anti-corrosion applications were widely studied and drawn much attention in both academe and industrial area. In this work, a systematic work, including inhibitors selection, anti-corrosion property and characterization, influence on scale formation, testing system design and so on, were reported. The corrosion inhibition performance of four imidazolium ionic liquids in carbon dioxide saturated NaCl solution was investigated by using electrochemical and surface analysis technologies. The four compounds are 1-ethyl-3-methylimidazolium chloride (a), 1-butyl-3-methylimidazolium chloride (b), 1-hexyl-3-methylimidazolium chloride (c), 1-decyl-3-methylimidazolium chloride (d). Under the testing conditions, compound d showed the highest inhibition efficiency and selected as the main object of further study. As a selected representative formula, 1-decyl-3-methylimidazolium chloride was studied in detail about its corrosion inhibition performance on mild steel in carbon dioxide saturated NaCl brine at pH 3.8 and 6.8. Electrochemical and surface analysis techniques were used to characterize the specimen corrosion process during the immersion in the blank and inhibiting solutions. The precorrosion of specimen surface showed significant and different influences on the anti-corrosion property of DMICL at pH 3.8 and 6.8. The corrosion inhibition efficiency (IE) was calculated based on parameters obtained from electrochemical techniques; the achieved IE was higher than 98% at the 25th hour for the steel with a well-polished surface at pH 3.8. The fitting parameters obtained from electrochemical data helped to account for the interfacial changes. As proved in previous research, 1-decyl-3-methylimidazolium chloride could be used as good corrosion inhibitors under certain conditions. However, under other conditions, such chemicals, as well as other species in oil transporting system, could be a factor influencing the evolution of protective surface

The corrosion and protection of less carbon containing steel in subsoil

International Nuclear Information System (INIS)

Kazimov, A. M; Mamedyarova, I. F; Selimkhanova, G. G; Bskhishova, D. A; Ibragimova, S. G.

2007-01-01

Full text: The protection and corrosion resistance of steel in subsoil waters of Baku subway were investigated. Kinetic curves were drawn. The results obtained from the experiment coincide with calculated results. There have been revealed and proposed hudron and fuel oil mixture protecting steel from corrosion in subsoil waters (97.8%) for the internal surface of steel pipes

Erosion Corrosion and Protection of Recycle System with Seawater

Directory of Open Access Journals (Sweden)

Xue Jin

2016-01-01

Full Text Available In order to investigate the corrosion of recycle system with seawater in rights of power plant, the erosion behavior and mechanism of erosion corrosion in this system constructed with several corrosionresistance alloys have been studied and tested in the condition of high speed fluid with a sand particles. Both special protection technologies and results, one designed by high temperature epoxy resin powder coating and another of the associating method of anode protection together with such same coating, have been discussed as well in this case.

A demonstration of on-line plant corrosion monitoring using thin layer activation

International Nuclear Information System (INIS)

Asher, J.; Webb, J.W.; Wilkins, N.J.M.; Lawrence, P.F.; UKAEA Atomic Energy Research Establishment, Harwell. Materials Development Div.)

1981-12-01

The corrosion of a 1 inch water pipe in an evaporative cooling system has been monitored over three periods of plant operation using thin layer activation (TLA). The corrosion rate was followed at a sensitivity of about 1 μm and clearly reflected changes in plant operation. Examination of the test section after removal, both by autoradiography and metallography revealed the extent of corrosion and pitting over the active area. (author)

Recommandations pour la protection des fonds de réservoirs contre la corrosion externe et interne Recommendations for Protecting Tank Bottoms Against External and Internal Corrosion

Directory of Open Access Journals (Sweden)

Chambre Syndicale du Pétrole

2006-11-01

Full Text Available Ce document analyse le sprincipales causes de corrosion externe et inerne des réservoirs de stockage à axe vertical et recommande diverses mesures de prévention. Pour la protection externe, ces mesures concernent la conception des fondations et des fonds et la protection cathodique our la protection interne, elles concernet l'inhibition chimique, la protection cathodique et surtout les revêtements. This article analyzes the leading causes of external ant internal corrosion of vertical-axis storage tanks ant reccomends different prevention measures to protect the outside these measures have to do with the design of the foundations and bottom as well as with cathodic protection. t protect the inside they have to do with chemical inhibition, cathodic production and espacially coatings.

An experimental estimation of the resistance against a high-temperature gas corrosion of C/C composite materials with protective plasma coating

International Nuclear Information System (INIS)

Babin, S.V.; Khripakov, E.V.

2007-01-01

Materials with well-defined structure has been proposed as corrosion- and erosion-resistant coating from the carbon-carbon composite. Experiments on heat and erosion resistance of plasma coatings at carbon-carbon composite materials demonstrate availability of multilayer with upper erosion resistant layer on the basis of aluminium oxide, intermediate layer on the basis of boron-containing components with aluminium additions and damping layer of silicon carbide. Multilayer protective coats offer demand service characteristics of details [ru

Effects of external stresses on hot corrosion behavior of stainless steel TP347HFG

International Nuclear Information System (INIS)

Fu, Jiapeng; Zhou, Qulan; Li, Na; Liu, Zhuhan; Liu, Taisheng

2016-01-01

Highlights: • Hot corrosion tests of TP347HFG under different stresses were conducted. • The corrosion resistance was strengthened by the exertion of tensile stresses. • External stresses promoted faster formation of the protective Cr_2O_3 layer. • Specimens under critical stress 40 MPa condition present the best resistance. - Abstract: Hot corrosion experiments of alloy TP347HFG under different stresses were conducted. Corroded specimens were examined by means of corrosion products, morphology and compositional changes in corrosion scales. The corrosion behavior was strongly associated with the formation of oxides layers. The corrosion resistance was strengthened by the external stress. It seemed that the exertion of stresses caused many micro cracks and defects, which acted as faster and easier diffusion paths for Cr atoms to diffuse to the surface, and thus, promote faster formation of the protective Cr_2O_3 oxide layer. Critical stress 40 MPa was found, specimens under which present the best resistance.

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

Science.gov (United States)

Gentil, Dana; del Campo, Valeria; Henrique Rodrigues da Cunha, Thiago; Henríquez, Ricardo; Garín, Carolina; Ramírez, Cristian; Flores, Marcos; Seeger, Michael

2017-01-01

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. PMID:29292763

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.

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.

Corrosion and carburization behavior of Al-rich surface layer on Ni-base alloy in supercritical-carbon dioxide environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Ho Jung, E-mail: leehojung@kaist.ac.kr; Kim, Sung Hwan, E-mail: sciencetom@kaist.ac.kr; Kim, Hyunmyung, E-mail: h46kim@kaist.ac.kr; Jang, Changheui, E-mail: chjang@kaist.ac.kr

2016-12-01

Highlights: • Al-rich layer was developed on Alloy 600 by Al deposition and EB remelting. • When exposed to S-CO{sub 2} at 600 °C, mostly Cr{sub 2}O{sub 3} with transition Al{sub 2}O{sub 3} was formed. • Carburized region of amorphous C layer was observed at the oxide/matrix interface. • α-Al{sub 2}O{sub 3} was formed after pre-oxidation which resulted in superior resistance. - Abstract: In order to improve the corrosion and carburization resistance in a high-temperature supercritical-carbon dioxide (S-CO{sub 2}) environment, an Al-rich surface layer was developed on Alloy 600 by Al deposition and a subsequent high energy electron beam (EB) remelting. As a result of the EB surface treatment, an Al enriched (5–7 wt.%) micro-alloying zone (40 μm) was produced. When the EB surface-treated Alloy 600 was corroded in S-CO{sub 2} at 600 °C (20 MPa) for 500 h, the surface oxide layer mostly consisted of chromia (Cr{sub 2}O{sub 3}) with small amount of transition alumina (Al{sub 2}O{sub 3}). In addition, a carburized region of an amorphous C layer inter-mixed with the alumina was observed at the oxide/matrix interface. Meanwhile, when the EB surface-treated specimen was pre-oxidized in helium at 900 °C, α-alumina layer was formed on the surface, which showed superior corrosion and carburization resistance in S-CO{sub 2} environment. Therefore, it could be said that the presence of Al-rich surface layer alone is not enough to provide sufficient corrosion and carburization resistance in S-CO{sub 2} environment at 600 °C, unless pre-oxidation at higher temperature is applied to form a more protective α-alumina on the surface.

Laboratory study of reinforcement protection with corrosion inhibitors

International Nuclear Information System (INIS)

Stefanescu, D.; Mihalache, M.; Mogosan, S.

2013-01-01

Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that degradation of the reinforced concrete structures caused by the corrosion of the reinforcing steel represents more than 80% of all damages in the world. Much effort has been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages in new structures. Migrating Corrosion Inhibitor technology was developed to protect the embedded steel rebar/concrete structure. These inhibitors can be incorporated as an admixture or can be surface impregnated on existing concrete structures. The effectiveness of two inhibitors (ethanolamine and diethanolamine) mixed in the reinforced concrete was evaluated by gravimetric measurements. The corrosion behavior of the steel rebar and the inhibiting effects of the amino alcohol chemistry in an aggressive environment were monitored using electrochemical measurements and scanning electron microscopy (SEM) investigations. (authors)

Protection against deposits and corrosion in water systems

Energy Technology Data Exchange (ETDEWEB)

Lehmkuhl, J

1978-11-01

Industry generally, including mining and coal preparation, are in the habit of using large amounts of untreated service water. The service water can be softened or treated with hardness stabilisers in order to prevent deposit formation and corrosion. As often as not, deposits of dirt and attack by microorganisma also have to be eliminated. The article puts forward some suggestions for practical assistance in protecting water systems against the dangers of deposits and corrosion.

Graphene coating for anti-corrosion and the investigation of failure mechanism

International Nuclear Information System (INIS)

Zhu, Y X; Duan, C Y; Chen, Y F; Wang, Y; Liu, H Y

2017-01-01

Graphene produced by chemical vapor deposition (CVD) methods has been considered as a promising corrosion prevention layer because of its exceptional structure and impermeability. However, the anti-corrosion performance and the failure mechanism are still controversial. In this study, graphene layers with different quality levels, crystallite sizes, and layer numbers were prepared on the surface of Cu by a CVD process. The effects of grain boundaries (GBs) on the failure of graphene layers to provide adequate protection were investigated in detail by combining graphene transfer techniques, computation, and anti-corrosion measurements. Our results reveal that corrosion rates decrease marginally upon the increase of graphene layer number, and this rather weak dependence on thickness likely arises from the aligned nature of the GBs in CVD-grown few-layer graphene. This problem can potentially be overcome by layer-by-layer graphene transfer technique, in which corrosion is found to be arrested locally when transferred graphene is present on top of the as-grown graphene. However, this advantage is not reflected in corrosion studies performed on large-scale samples, where cracks or imperfect interfaces could offset the advantages of GB misalignment. With improvements in technology, the layer-by-layer assembly technique could be used to develop an effective anti-corrosion barrier. (paper)

Influence of temperature on corrosion rate and porosity of corrosion products of carbon steel in anoxic bentonite environment

International Nuclear Information System (INIS)

Stoulil, J.; Kaňok, J.; Kouřil, M.; Parschová, H.; Novák, P.

2013-01-01

Highlights: •The corrosion rate is not significantly dependent on temperature. •Corrosion products at higher temperatures have different color. •Corrosion products at higher temperatures are more compact. •The change in corrosion products nature is reversible. -- Abstract: The study focuses on the porosity of layers of corrosion products and its impact on corrosion rate of carbon steel in moist bentonite. Measurements were performed in an aggressive Czech type of bentonite – Rokle B75 at temperatures of 90 and 40 °C. Aggressiveness of B75 bentonite consists in low content of chlorides. Presence of chlorides in pore solution allows formation of more protective magnetite. The evaluation was made by electrochemical techniques (red/ox potential, open circuit potential, linear polarization resistance, impedance spectroscopy) and resistometric sensor measurements. The result imply that the higher the temperature the more compact is the layer of corrosion products that slightly decelerates corrosion rate compared to the state at 40 °C. The state of corrosion products at both temperatures is reversible

Influence of temperature on corrosion rate and porosity of corrosion products of carbon steel in anoxic bentonite environment

Energy Technology Data Exchange (ETDEWEB)

Stoulil, J., E-mail: jan.stoulil@vscht.cz [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague (Czech Republic); Kaňok, J.; Kouřil, M. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague (Czech Republic); Parschová, H. [Department of Power Engineering, Institute of Chemical Technology, Prague (Czech Republic); Novák, P. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague (Czech Republic)

2013-11-15

Highlights: •The corrosion rate is not significantly dependent on temperature. •Corrosion products at higher temperatures have different color. •Corrosion products at higher temperatures are more compact. •The change in corrosion products nature is reversible. -- Abstract: The study focuses on the porosity of layers of corrosion products and its impact on corrosion rate of carbon steel in moist bentonite. Measurements were performed in an aggressive Czech type of bentonite – Rokle B75 at temperatures of 90 and 40 °C. Aggressiveness of B75 bentonite consists in low content of chlorides. Presence of chlorides in pore solution allows formation of more protective magnetite. The evaluation was made by electrochemical techniques (red/ox potential, open circuit potential, linear polarization resistance, impedance spectroscopy) and resistometric sensor measurements. The result imply that the higher the temperature the more compact is the layer of corrosion products that slightly decelerates corrosion rate compared to the state at 40 °C. The state of corrosion products at both temperatures is reversible.

Local environmental conditions and the stability of protective layers on steel surfaces

Energy Technology Data Exchange (ETDEWEB)

Jensen, J P [Technical Univ. of Denmark, Lyngby (Denmark); Bursik, A

1996-12-01

Local environmental conditions determine whether the protective layers on steel surfaces are stable. With unfavorable local environmental conditions, the protective layers may be subject to damage. Taking the cation conductivity of all plant cycle streams <0.2 {mu}S/cm for granted, an adequate feed-water and - if applicable - boiler water conditioning is required to prevent such damage. Even if the mentioned conditions are met in a bulk, the local environmental conditions may be inadequate. The reasons for this may be the disregarding of interactions among material, design, and chemistry. The paper presents many possible mechanisms of protective layer damage that are directly influenced or exacerbated by plant cycle chemistry. Two items are discussed in more detail: First, the application of all volatile treatment for boiler water conditioning of drum boiler systems operating at low pressures and, second, the chemistry in the transition zone water/steam in the low pressure turbine. The latter is of major interest for the understanding and prevention of corrosion due to high concentration of impurities in the aqueous liquid phases. This is a typical example showing that local environmental conditions may fundamentally differ from the overall bulk chemistry. (au) 19 refs.

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.

Recent Research and Development in Solving Atmospheric Corrosion Problems of Steel Industries in Japan

International Nuclear Information System (INIS)

Yamashita, M.; Uchida, H.

2002-01-01

A rust layer, so called 'protective' rust layer, on a weathering low-alloy steel has strong protective ability for atmospheric corrosion of the steel. We have recently found through a large number of spectroscopic studies including Moessbauer spectroscopy that the protective rust layer forms after long-term phase transformation. The phase and structure of the rust definitely control the protective ability of the rust layer. From this recent knowledge, some new technologies have been developed. One is the surface-treatment technique that provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environments such as in marine and chloride (de-icing salts) containing environments. Others are based on selection of effective alloying elements for steel materials. These are particularly important for application in areas where protective rust layer formation may be hindered or prevented. In this paper, we mention recent progress in research and development on rusting protection by rust for atmospheric corrosion of steels in Japan.

Anion embedded sol-gel films on Al for corrosion protection

International Nuclear Information System (INIS)

Sheffer, Mari; Groysman, Alec; Starosvetsky, David; Savchenko, Natali; Mandler, Daniel

2004-01-01

We report here on the successful incorporation of organic anions into a sol-gel film on Al as a means of enhancing the protection against corrosion. Following our previous study where we showed that hydrophobic sol-gel films provided pronounced corrosion inhibition, we studied the corrosion inhibition that phenylphosphonic acid (PPA) has when embedded inside a thin sol-gel coating on Al. The anion of this organic anion tends to stay inside a phenyltrimethoxysilane (PTMOS) based sol-gel film due to π-interactions. Our findings, which are derived primarily from potentiodynamic polarization measurements, electrochemical noise, scanning electron microscopy measurements and Auger electron spectroscopy (AES), clearly show that the organic phosphonate adds to the protection efficiency of the sol-gel film

Magnetic strength and corrosion of rare earth magnets.

Science.gov (United States)

Ahmad, Khalid A; Drummond, James L; Graber, Thomas; BeGole, Ellen

2006-09-01

Rare earth magnets have been used in orthodontics, but their corrosion tendency in the oral cavity limits long-term clinical application. The aim of this project was to evaluate several; magnet coatings and their effects on magnetic flux density. A total of 60 neodymium-iron-boron magnets divided into 6 equal groups--polytetrafluoroethylene-coated (PTFE), parylene-coated, and noncoated--were subjected to 4 weeks of aging in saline solution, ball milling, and corrosion testing. A significant decrease in magnet flux density was recorded after applying a protective layer of parylene, whereas a slight decrease was found after applying a protective layer of PTFE. After 4 weeks of aging, the coated magnets were superior to the noncoated magnets in retaining magnetism. The corrosion-behavior test showed no significant difference between the 2 types of coated magnets, and considerable amounts of iron-leached ions were seen in all groups. Throughout the processes of coating, soaking, ball milling, and corrosion testing, PTFE was a better coating material than parylene for preserving magnet flux density. However, corrosion testing showed significant metal leaching in all groups.

Surface treatment and history-dependent corrosion in lead alloys

International Nuclear Information System (INIS)

Li Ning; Zhang Jinsuo; Sencer, Bulent H.; Koury, Daniel

2006-01-01

In oxygen-controlled lead and lead-bismuth eutectic (LBE), steel corrosion may be strongly history dependent. This is due to the competition between liquid metal dissolution corrosion and oxidation as a 'self-healing' protection barrier. Such effects can be observed from corrosion testing of a variety of surface-treated materials, such as cold working, shot peening, pre-oxidation, etc. Shot peening of austenitic steels produces surface-layer microstructural damages and grain compression, which could contribute to increased Cr migration to the surface and enhance the protection through an impervious oxide. Pre-oxidation under conditions different from operating ones may form more protective oxides, reduce oxygen and metal ion migration through the oxides, and achieve better protection for longer durations. Corrosion and oxidation modeling and analysis reveal the potential for significantly reducing long-term corrosion rates by initial and early-stage conditioning of steels for Pb/LBE services

Surface treatment and history-dependent corrosion in lead alloys

Energy Technology Data Exchange (ETDEWEB)

Li Ning [Los Alamos National Laboratory, Los Alamos, NM (United States)]. E-mail: ningli@lanl.gov; Zhang Jinsuo [Los Alamos National Laboratory, Los Alamos, NM (United States); Sencer, Bulent H. [Los Alamos National Laboratory, Los Alamos, NM (United States); Koury, Daniel [University of Nevada, Las Vegas, NV (United States)

2006-06-23

In oxygen-controlled lead and lead-bismuth eutectic (LBE), steel corrosion may be strongly history dependent. This is due to the competition between liquid metal dissolution corrosion and oxidation as a 'self-healing' protection barrier. Such effects can be observed from corrosion testing of a variety of surface-treated materials, such as cold working, shot peening, pre-oxidation, etc. Shot peening of austenitic steels produces surface-layer microstructural damages and grain compression, which could contribute to increased Cr migration to the surface and enhance the protection through an impervious oxide. Pre-oxidation under conditions different from operating ones may form more protective oxides, reduce oxygen and metal ion migration through the oxides, and achieve better protection for longer durations. Corrosion and oxidation modeling and analysis reveal the potential for significantly reducing long-term corrosion rates by initial and early-stage conditioning of steels for Pb/LBE services.

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).

Corrosion processes of alloyed steels in salt solutions

Energy Technology Data Exchange (ETDEWEB)

Kienzler, Bernhard [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Institut fuer Nukleare Entsorgung

2018-02-15

A summary is given of the corrosion experiments with alloyed Cr-Ni steels in salt solutions performed at Research Centre Karlsruhe (today KIT), Institute for Nuclear Waste Disposal (INE) in the period between 1980 and 2004. Alloyed steels show significantly lower general corrosion in comparison to carbon steels. However, especially in salt brines the protective Cr oxide layers on the surfaces of these steels are disturbed and localized corrosion takes place. Data on general corrosion rates, and findings of pitting, crevice and stress corrosion cracking are presented.

Boron nitride nanosheets as oxygen-atom corrosion protective coatings

International Nuclear Information System (INIS)

Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

2014-01-01

The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion

Slow positron beam study of corrosion behavior of AM60B magnesium alloy in NaCl solution

International Nuclear Information System (INIS)

Yang, W.; Zhu, Z.J.; Wang, J.J.; Wu, Y.C.; Zhai, T.; Song, G.-L.

2016-01-01

Highlights: • Positron annihilation is a sensitive tool to characterize the corrosion layer. • The interfacial voids promoted the formation of Mg(OH) 2 corrosion layer. • Mg(OH) 2 precipitated during early corrosion stage provided a temporary protection. - Abstract: The corrosion behavior of super vacuum die-cast AM60B magnesium alloys immersed in a 5 wt% NaCl solution was investigated by slow positron beam technique, XRD, XPS, SEM and potentiodynamic polarization tests. The XRD and XPS results indicated that Mg(OH) 2 was main corrosion product in the salt solution. With prolonging the immersion time, a significant decrease of Doppler-broadened annihilation line-width parameter near the surface after corrosion was observed and interpreted that the pre-existing interfacial voids between oxide film and matrix might promote the formation of Mg(OH) 2 corrosion layer. Polarization tests found that Mg(OH) 2 could provide a temporary protection.

Corrosion protection of Arctic offshore structures: Final report. [Effects of temperature and salinity on required cathodic protection current

Energy Technology Data Exchange (ETDEWEB)

Sackinger, W.M.; Rogers, J.C.; Feyk, C.; Theuveny, B.

1985-10-01

Results are presented for a research program on corrosion prevention for Arctic offshore structures which are in contact with sea ice for a significant portion of the year. The electrical method most adaptable for structure protection involves the injection of impressed current from several remote anodes buried just beneath the sea floor. The electrical resistivity of annual sea ice as a function of temperature and salinity is presented. Details of the interface layers formed between sea ice and steel in the presence of current injection are shown. A computer program was developed to enable the calculation of protective current density into the structure, in the presence of ice rubble and ridges around the structure. The program and the results of an example calculation are given for a caisson- retained island structure. 81 refs., 103 figs., 3 tabs.

Insitu grown superhydrophobic Zn–Al layered double hydroxides films on magnesium alloy to improve corrosion properties

Energy Technology Data Exchange (ETDEWEB)

Zhou, Meng; Pang, Xiaolu; Wei, Liang; Gao, Kewei, E-mail: kwgao@yahoo.com

2015-05-15

Highlights: • Hierarchical superhydrophobic Zn–Al LDHs film has been fabricated on a magnesium alloy substrate. • The superhydrophobic surface has good long-term stability under atmospheric environment. • The superhydrophobic surface can provide a stable corrosion protection for the Mg alloys. - Abstract: A hierarchical superhydrophobic zinc–aluminum layered double hydroxides (Zn–Al LDHs) film has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method following chemical modification. The characteristics of the films were investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM), and energy dispersive spectroscopy (EDS). XRD patterns and SEM images showed that the micro/nanoscale hierarchical LDHs film surfaces composed of ZnO nanorods and Zn–Al LDHs nanowalls structures. The static contact angle (CA) for the prepared surfaces was observed at around 165.6°. The corrosion resistance of the superhydrophobic films was estimated by electrochemical impedance spectroscopy (EIS) and potentiondynamic polarization measurement. EIS and polarization measurements revealed that the superhydrophobic Zn–Al LDHs coated magnesium alloy had better corrosion resistance in neutral 3.5 wt.% NaCl solution.

Insitu grown superhydrophobic Zn–Al layered double hydroxides films on magnesium alloy to improve corrosion properties

International Nuclear Information System (INIS)

Zhou, Meng; Pang, Xiaolu; Wei, Liang; Gao, Kewei

2015-01-01

Highlights: • Hierarchical superhydrophobic Zn–Al LDHs film has been fabricated on a magnesium alloy substrate. • The superhydrophobic surface has good long-term stability under atmospheric environment. • The superhydrophobic surface can provide a stable corrosion protection for the Mg alloys. - Abstract: A hierarchical superhydrophobic zinc–aluminum layered double hydroxides (Zn–Al LDHs) film has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method following chemical modification. The characteristics of the films were investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM), and energy dispersive spectroscopy (EDS). XRD patterns and SEM images showed that the micro/nanoscale hierarchical LDHs film surfaces composed of ZnO nanorods and Zn–Al LDHs nanowalls structures. The static contact angle (CA) for the prepared surfaces was observed at around 165.6°. The corrosion resistance of the superhydrophobic films was estimated by electrochemical impedance spectroscopy (EIS) and potentiondynamic polarization measurement. EIS and polarization measurements revealed that the superhydrophobic Zn–Al LDHs coated magnesium alloy had better corrosion resistance in neutral 3.5 wt.% NaCl solution

Simultaneous sound velocity and thickness measurement by the ultrasonic pitch-catch method for corrosion-layer-forming polymeric materials.

Science.gov (United States)

Kusano, Masahiro; Takizawa, Shota; Sakai, Tetsuya; Arao, Yoshihiko; Kubouchi, Masatoshi

2018-01-01

Since thermosetting resins have excellent resistance to chemicals, fiber reinforced plastics composed of such resins and reinforcement fibers are widely used as construction materials for equipment in chemical plants. Such equipment is usually used for several decades under severe corrosive conditions so that failure due to degradation may result. One of the degradation behaviors in thermosetting resins under chemical solutions is "corrosion-layer-forming" degradation. In this type of degradation, surface resins in contact with a solution corrode, and some of them remain asa corrosion layer on the pristine part. It is difficult to precisely measure the thickness of the pristine part of such degradation type materials by conventional pulse-echo ultrasonic testing, because the sound velocity depends on the degree of corrosion of the polymeric material. In addition, the ultrasonic reflection interface between the pristine part and the corrosion layer is obscure. Thus, we propose a pitch-catch method using a pair of normal and angle probes to measure four parameters: the thicknesses of the pristine part and the corrosion layer, and their respective sound velocities. The validity of the proposed method was confirmed by measuring a two-layer sample and a sample including corroded parts. The results demonstrate that the pitch-catch method can successfully measure the four parameters and evaluate the residual thickness of the pristine part in the corrosion-layer-forming sample. Copyright © 2017 Elsevier B.V. All rights reserved.

Thin layer activation: measuring wear and corrosion

International Nuclear Information System (INIS)

Delvigne, T.; Leyman, D.; Oxorn, K.

1995-01-01

The technique known as thin layer activation (TLA) is explained and assessed in this article. Widely used, in for example the automotive industry, TLA allows on-line monitoring of the loss of matter from a critical surface, by wear erosion and corrosion. The technique offers extremely high sensitivity thus leading to reduced test times. On-line wear phenomena can be assessed during operation of a mechanical process, even through thick engine walls. (UK)

Development of a phosphating process for corrosion protection in NdFeB magnets

International Nuclear Information System (INIS)

Silva, Adonis Marcelo Saliba

2001-01-01

NdFeB magnets are important materials, which produce better energy efficiency in electrical devices, but they are rather vulnerable to corrosion. In this study, a phosphating treatment for protection against corrosion of NdFeB magnets has been investigated. Phosphating is generally used as a pretreatment in the application of protective coatings. This treatment increases the corrosion assistance in defective areas of the coating as well as improves the adhesion between coating and substrate. A commercial NdFeB magnet produced by powder metallurgy has been used and the effect of the following parameters on phosphating was studied: time of phosphating; pH of phosphating solution; anodic polarization and molybdate addition to the phosphating solution. The results showed a significant increase in the corrosion resistance of magnets phosphated in a solution concentrated between 10-20 g/L NaH 2 PO 4 , pH in the range of 3 to 4.6, acidulated preferably with H 3 PO 4 at room temperature (20±1) deg C. Conversion coatings formed at solutions of pH 3.8 showed better corrosion resistance. Phosphating times longer than 4 hours increased the magnet corrosion resistance 10 to 20 times. This resistance improves with higher immersion times. Anodic polarization of the magnet in the range 200-400 mV SCE accelerated phosphating. Results indicated that molybdate interacts preferentially with Nd rich phase of the magnet. In addition to the newly developed technology in this work for NdFeB corrosion protection, two methodologies have been introduced to facilitate electrochemical analyses: selection of samples of similar electrochemical behavior, based on the current density after 200s of constant anodic polarization; and evaluation of the corrosion protection provided by conversion coatings by monitoring of gas evolution during corrosion in acid solution. (author)

Corrosion protection method by neutral treatment for boilers

International Nuclear Information System (INIS)

Ishikawa, Hisashige

1978-01-01

The corrosion protection method by neutral treatment has been applied in Europe mainly for boilers and nuclear reactors instead of existing all volatile treatment. The cause of corrosion of steel and copper in water and the effect of neutral treatment, that is the effect of protection film of magnetite in steel and cuprous oxide in copper alloy, are explained with the characteristic figure of PH, electromotive force and chemical formula. The experience of applying this neutral treatment to the Wedel thermal power plant and the system flow sheet, the water treatment equipment, relating instrumentations and the water examination are described in detail. Hydrogen peroxide is injected in this neutral treatment. The comparison between the existing water treatment and the neutral treatment and their merits and demerits are explained. (Nakai, Y.)

Research on atmospheric corrosion of steel using synchrotron radiation

International Nuclear Information System (INIS)

Yamashita, M.; Uchida, H.; Konishi, H.; Mizuki, J.

2004-01-01

Correlation between local structure around Cr in the protective rust layer on weathering steel and protective performance of the rust layer is presented as an example of corrosion research using synchrotron radiation which has recently been applied in various research fields as a useful tool. In addition, in situ observation of initial process of rust formation on steel is also mentioned. It was pointed out by considering the X-ray absorption fine structure spectra that the nanostructure of the protective rust layer on weathering steel primarily comprises of small Cr-goethite crystals containing surface adsorbed and/or intergranular CrO x 3-2X complex anions. This CrO x 3-2X explains the protective performance of the rust layer originated by dense aggregation of fine crystals with cation selectivity of the Cr-goethite. It is very advantageous to employ white X-rays for in situ observation of rusting process of a carbon steel covered with electrolyte thin films because rust structure might change very quickly. This in situ observation revealed the effect of ion species on the change in rust phase during wet/dry repeating. It can be said that application of synchrotron radiation on corrosion research is so useful to understand the nanostructure of surface oxides which closely relate to corrosion behavior of metals and alloys. (author)

Micro-EDXRF surface analyses of a bronze spear head: Lead content in metal and corrosion layers

International Nuclear Information System (INIS)

Figueiredo, E.; Valerio, P.; Araujo, M.F.; Senna-Martinez, J.C.

2007-01-01

A bronze spear head from Central Portugal dated to Late Bronze Age has been analyzed by non-destructive micro-EDXRF in the metal surface and corrosion layers. The artifact had previously been analyzed using a conventional EDXRF spectrometer having a larger incident beam. The quantification of the micro-EDXRF analyses showed that lead content in corrosion layers can reach values up to four times higher than the content determined in the metal surface. Results obtained with the higher energy incident beam from the EDXRF equipment, although referring mainly to the corrosion layers, seem to suffer some influence from the surface composition of the metallic alloy

Corrosion Performance of Composite Galvanic Coatings with Variable Concentration of Polymeric Nanoaggregates and/or Cr(III) Conversion Layers

NARCIS (Netherlands)

Koleva, D.A.; Taheri, P.; Tsvetkova, N.; Boshkov, N.; Van Breugel, K.; De Wit, J.H.W.; Mol, J.M.C.

2011-01-01

This paper reports on the corrosion performance of composite zinc layers (~ 8µm) on a steel substrate, considering the influence of nano-aggregates and Cr(III) conversion layers, compared to control (only Zn layers) conditions. The main factors, influencing the corrosion performance of Zn in this

Experiences of corrosion and corrosion protection in seawater systems in the Nordic countries

International Nuclear Information System (INIS)

Henrikson, S.

1985-01-01

A summary is given of the experience of the corrosion resistance of pumps, heat exchangers, valves and pipings in different seawater cooling systems in Scandinavia, including power reactor cooling systems in Finland and Sweden. For pumps and heat exchangers the experience has been so extensive that a clear picture of today's standing can be given. Owing to scanty data concerning valves and pipes, the survey of the corrosion in these components is less well supported. Vertically extended centrifugal pumps are the pumps in general use in power plant cooling systems. To counteract corrosion on pump riser and pump casing having an organic surface coating, and on stainless steel shafts and impellers, these components should be provided with internal and external cathodic protection. For tube and plate type heat exchangers, titanium has proved to be the best material choice. Rubber-enclosed carbon steel pipings, or pipings having a thick coating of epoxy plastic, have shown very strong corrosion resistance in power plant seawater cooling systems. Valves in seawater systems have primarily been affected by corrosion due to poorly executed or damaged organic coating on cast iron. Different seawater-resistant bronzes (red bronze, tin bronze and aluminium bronze) are therefore preferable as valve materials

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.

Corrosion protective performance of amino trimethylene phosphonic acid-metal complex layers fabricated on the cold-rolled steel substrate via one-step assembly

Science.gov (United States)

Yan, Ru; He, Wei; Zhai, Tianhua; Ma, Houyi

2018-06-01

Seeing that amino trimethylene phosphonic acid (ATMP) possesses very strong complexation ability to metal ions and the phosphonic acid group has good affinity for the oxidized iron surface, herein a simple and rapid film-forming method (one-step assembly method) was developed to construct the ATMP-Zn complex conversion layers (ATMP-Zn layers for short) on the cold-rolled steel (CRS) substrate. Zinc ions were found to participate in the formation process of ATMP-based composite film, which made the Zn-containing ATMP film significantly different in appearance, thickness, microstructure and film-forming mechanisms from the Zn-free ATMP film. There was mainly iron (ш) phosphonate in the Zn-free ATMP film, whereas there were Zn2+-ATMP complex and a certain amount of ZnO in the ATMP-Zn composite film. In addition, electrochemical test results clearly indicate that corrosion resistance of ATMP-Zn composite film was greatly enhanced due to the presence of Zn component. Moreover, the corrosion resistance performance could be controlled by adjusting film-forming time, pH and ATMP concentration in the film-forming solutions. The present study provides a new method for the design and fabrication of high-quality environmentally-friendly conversion layers.

EIS study on corrosion and scale processes and their inhibition in cooling system media

International Nuclear Information System (INIS)

Marin-Cruz, J.; Cabrera-Sierra, R.; Pech-Canul, M.A.; Gonzalez, I.

2006-01-01

A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media

EIS study on corrosion and scale processes and their inhibition in cooling system media

Energy Technology Data Exchange (ETDEWEB)

Marin-Cruz, J. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico) and Instituto Mexicano del Petroleo, Coordinacion de Ingenieria Molecular, Competencia de Quimica Aplicada, Eje Central Lazaro Cardenas No. 152, CP 07730, DF (Mexico)]. E-mail: jmarin@imp.mx; Cabrera-Sierra, R. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico); Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE-IPN), Departamento de Metalurgia, UPALM Zacatenco AP 75-874, CP 07338, DF (Mexico); Pech-Canul, M.A. [Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios, Avanzados del IPN, AP 73 Cordemex, CP 97310, Merida, Yucatan (Mexico); Gonzalez, I. [Universidad Autonoma Metropolitana, Departamento de Quimica, Apdo. Postal 55-534, 09340 Mexico, DF (Mexico)]. E-mail: igm@xanum.uam.mx

2006-01-20

A study of the carbon steel/cooling water interface was carried out using electrochemical impedance spectroscopy (EIS). EIS spectra reveal that a layer of corrosion and scale products forms naturally and evolves with the immersion time modifying the carbon steel/cooling water interface and giving rise to corrosion and scale processes. In addition, the nature of the layer formed on the metal was found to depend on the inhibitor used. It was established that the corrosion inhibitor (hydroxyphosphonoacetic acid (HPA)) chelates with Ca(II) ion generating a layer with resistive properties that provides good protection against corrosion. In contrast, the scale inhibitor (1-hydroxy-ethane-1,1-diphosphonic acid (HEDP)) is incorporated into the calcium carbonate crystals at the surface, modifying the structure and diminishing scale formation in the surface; this additive additionally inhibited corrosion. These observations were supported by scanning electronic microscopy (SEM) and corroborate previous studies performed by other techniques on HPA and HEDP. Finally, a synergistic effect was observed between these inhibitors that provides good protection to steel against corrosion and scaling in cooling media.

Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

International Nuclear Information System (INIS)

Xu Jiang; Tao Jie; Jiang Shuyun; Xu Zhong

2008-01-01

In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2 O 3 , MoO 3 , SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

Improved corrosion resistance of spin-valve film

International Nuclear Information System (INIS)

Tetsukawa, H.; Hommura, H.; Okabe, A.; Soda, Y.

2007-01-01

We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head

Improved corrosion resistance of spin-valve film

Energy Technology Data Exchange (ETDEWEB)

Tetsukawa, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Hommura, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Okabe, A. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Soda, Y. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

2007-06-15

We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head.

Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

Energy Technology Data Exchange (ETDEWEB)

Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe{sub 3}O{sub 4} and NiFe{sub 2}O{sub 4}. On the other hand, the inner oxide layers are composed of Cr{sub 2}O{sub 3}, (Ni{sub 1-x}Ni{sub x})(Cr{sub 1-y}Fe{sub y}){sub 2}O{sub 4}, and FeCr{sub 2}O{sub 4}. Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications

Corrosion Compatibility Studies on Inconel-600 in NP Decontamination Solution

International Nuclear Information System (INIS)

Park, Sang Yoon; Jung, Jun Young; Won, Huijun; Choi, Wangkyu; Moon, Jeikwon

2013-01-01

It is well known that corrosion and contamination process in the primary cooling circuit of nuclear reactors are essentially interrelated: the contaminant isotopes are mostly corrosion products activated in the reactor core, and the contamination takes place on the out-core of Inconel-600 surface. This radionuclide uptake takes place up to the inner oxide layer and oxide/metal interface. So, it is necessary to remove inner oxide layer as well as outer oxide layer for excellent decontamination effects. The outer oxide layers are composed of Fe 3 O 4 and NiFe 2 O 4 . On the other hand, the inner oxide layers are composed of Cr 2 O 3 , (Ni 1-x Ni x )(Cr 1-y Fe y ) 2 O 4 , and FeCr 2 O 4 . Because of chromium in the trivalent oxidation state which is difficult to dissolve, the oxide layer has an excellent protectiveness and become hard to be decontaminated. Alkaline permanganate (AP) or nitric permanganate (NP) oxidative phase has been used to dissolve the chromium-rich oxide. A disadvantage of AP process is the generation of a large volume of secondary waste. On the other hand, that of NP process is the high corrosion rate for Ni-base alloys. Therefore, for the safe use of oxidative phase in PWR system decontamination, it is necessary to reformulate the NP chemicals for decrease of corrosion rate. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. To evaluate the general corrosion properties, weight change of NP treated specimens was measured. NP treated specimen surface was observed using optical microscope (OM) and scanning electron microscopy (SEM) for the evaluation of the localized corrosion. The effect of additives on the corrosion of the specimens was also evaluated. This study describes the corrosion compatibility on Inconel-600 and type 304 stainless steel in NP decontamination solution for PWR applications. It is revealed that Inconel-600 specimen is more

Corrosion protection of Mg-5Li alloy with epoxy coatings containing polyaniline

International Nuclear Information System (INIS)

Shao Yawei; Huang Hui; Zhang Tao; Meng Guozhe; Wang Fuhui

2009-01-01

The protective ability of epoxy coating containing polyaniline (PANI coating) on Mg-5Li alloy in 3.5% NaCl aqueous solution has been studied by means of EIS and electrochemical noise measurements (EN). The results of EN and EIS revealed that the PANI coating protected Mg-5Li alloy from corrosion perfectly. XPS results indicated that the presence of polyaniline changed the chemical structure of the corrosion film on the alloy surface. An analysis of the electrochemical noise data based on stochastic analysis indicated that the corrosion growth probability of Mg-5Li alloy beneath the coating was decreased by the addition of polyaniline.

Electrochemical Corrosion Behavior of Oxidation Layer on Fe30Mn5Al Alloy

Directory of Open Access Journals (Sweden)

ZHU Xue-mei

2017-08-01

Full Text Available The Fe30Mn5Al alloy was oxidized at 800℃ in air for 160h, the oxidation-induced layer about 15μm thick near the scale-metal interface was induced to transform to ferrite and become enriched in Fe and depletion in Mn. The effect of the oxidation-induced Mn depletion layer on the electrochemical corrosion behavior of Fe30Mn5Al alloy was evaluated. The results show that in 1mol·L-1 Na2SO4 solution, the anodic polarization curve of the Mn depletion layer exhibits self-passivation, compared with Fe30Mn5Al austenitic alloy, and the corrosion potential Evs SCE is increased to -130mV from -750mV and the passive current density ip is decreased to 29μA/cm2 from 310μA/cm2. The electrochemical impedance spectroscopy(EIS of the Mn depletion layer has the larger diameter of capacitive arc, the higher impedance modulus|Z|, and the wider phase degree range, and the fitted polarization resistant Rt is increased to 9.9kΩ·cm2 from 2.7kΩ·cm2 by using an equivalent electric circuit of Rs-(Rt//CPE. The high insulation of the Mn depletion layer leads to an improved corrosion resistance of Fe30Mn5Al austenitic alloy.

Evaluation of corrosion products formed by sulfidation as inhibitors of the naphthenic corrosion of AISI-316 steel

Science.gov (United States)

Sanabria-Cala, J. A.; Montañez, N. D.; Laverde Cataño, D.; Y Peña Ballesteros, D.; Mejía, C. A.

2017-12-01

Naphthenic acids present in oil from most regions worldwide currently stand as the main responsible for the naphthenic corrosion problems, affecting the oil-refining industry. The phenomenon of sulfidation, accompanying corrosion processes brought about by naphthenic acids in high-temperature refining plant applications, takes place when the combination of sulfidic acid (H2S) with Fe forms layers of iron sulphide (FeS) on the material surface, layers with the potential to protect the material from attack by other corrosive species like naphthenic acids. This work assessed corrosion products formed by sulfidation as inhibitors of naphthenic corrosion rate in AISI-316 steel exposed to processing conditions of simulated crude oil in a dynamic autoclave. Calculation of the sulfidation and naphthenic corrosion rates were determined by gravimetry. The surfaces of the AISI-316 gravimetric coupons exposed to acid systems; were characterized morphologically by X-Ray Diffraction (XRD) and X-ray Fluorescence by Energy Dispersive Spectroscopy (EDS) combined with Scanning Electron Microscopy (SEM). One of the results obtained was the determination of an inhibiting effect of corrosion products at 250 and 300°C, where lower corrosion rate levels were detected. For the temperature of 350°C, naphthenic corrosion rates increased due to deposition of naphthenic acids on the areas where corrosion products formed by sulfidation have lower homogeneity and stability on the surface, thus accelerating the destruction of AISI-316 steel. The above provides an initial contribution to oil industry in search of new alternatives to corrosion control by the attack of naphthenic acids, from the formation of FeS layers on exposed materials in the processing of heavy crude oils with high sulphur content.

Astrakhan-Mangyshlak water main (pipeline): corrosion state of the inner surface, and methods for its corrosion protection. Part III. The effects of KW2353 inhibitor. Part IV. Microbiological corrosion

International Nuclear Information System (INIS)

Reformatskaya, I.I.; Ashcheulova, I.I.; Barinova, M.A.; Kostin, D.V.; Prutchenko, S.G.; Ivleva, G.A.; Taubaldiev, T.S.; Murinov, K.S.; Tastanov, K.Kh.

2003-01-01

The effect of the KW2353 corrosion inhibitor, applied on the Astrakhan-Mangyshlak water main (pipeline) since 1997, on the corrosion processes, occurring on the 17G1S steel surface, is considered. The properties of the surface sediments are also considered. The role of the microbiological processes in the corrosion behavior of the water main (pipeline) inner surface is studied. It is shown, that application of the polyphosphate-type inhibitors, including the KW2353 one, for the anticorrosive protection of the inner surface of the extended water main (pipelines) is inadmissible: at the temperature of ∼20 deg C this corrosion inhibitor facilitates the development of the local corrosion processes on the water main (pipeline) inner surface. At the temperature of ∼8 deg C the above inhibitor discontinues to effect the corrosive stability of the 17G1S steel. The optimal way of the anticorrosive protection of the steel equipment, contacting with the water media, is the increase in the oxygen content therein [ru

Corrosion of Steel in Concrete, Part I – Mechanisms

DEFF Research Database (Denmark)

Küter, André; Møller, Per; Geiker, Mette Rica

2006-01-01

prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress...... of depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...... initiation and propagation of corrosion of steel in concrete are outlined....

Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

Science.gov (United States)

Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

2002-01-01

The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

Prospects of ion implantation and ion beam mixing for corrosion protection

International Nuclear Information System (INIS)

Wolf, G.K.; Munn, P.; Ensinger, W.

1985-01-01

Ion implantation is very useful new low temperature treatment for improving the mechanical surface properties of materials without any dimensional changes. In addition also the corrosion properties of metals can be modified considerably by this technique. The long term corrosion behaviour of implanted metals, however, has been studied only for a very limited number of cases. In this contribution a survey of attempts to do this will be presented. As examples of promising systems for corrosion protection by ion beams iron, steel and titanium were examined with and without pretreatment by ion implantation and ion beam mixing. The corrosion rates of the systems have been obtained by neutron activation analysis and by electrochemical methods. Experimental results are presented on: Palladium implanted in titanium - crevice corrosion in salt solution; Palladium implanted in and deposited on titanium -corrosion in sulfuric acid; Platinum implanted in stainless steel -corrosion in sulfuric acid. (author)

Pitting corrosion protection of low nickel stainless steel

Indian Academy of Sciences (India)

The corrosion protective properties of PANi and PoPD coatings on LN SS in 0.5 M NaCl were evaluated using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) techniques. The potentiodynamic polarization and electrochemical impedance spectroscopic results indicate that the PoPD ...

Influence of Silane modified nano silica on the corrosion protection of zinc rich coating

International Nuclear Information System (INIS)

Nguyen Thuy Duong; To Thi Xuan Hang; Trinh Anh Truc; Pham Gia Vu; Bui Van Truoc; Thai Hoang

2015-01-01

Zinc rich coatings are the best effective primers for corrosion protection of carbon steel in aggressive conditions. For traditional zinc rich primer the zinc content is very high, more than 90 wt.%. The coating adhesion is decreased with the increase of zinc content, so that it is necessary to decrease the zinc content by using additives. In this study the nano silica modified by N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane was prepared and incorporated in zinc rich epoxy coatings containing 85 wt.% zinc powder. The corrosion protection performance of coatings was evaluated by electrochemical impedance spectroscopy. The results obtained show that the presence of nano silica improved corrosion protection of zinc rich epoxy coating and the best protection was obtained with 3 wt.% nano silica. (author)

Improvement of corrosion protection property of Mg-alloy by DLC and Si-DLC coatings with PBII technique and multi-target DC-RF magnetron sputtering

International Nuclear Information System (INIS)

Masami, Ikeyama; Setsuo, Nakao; Tsutomu, Sonoda; Junho, Choi

2009-01-01

Magnesium alloys have been considered as one of the most promising light weight materials with potential applications for automobile and aircraft components. Their poor corrosion resistance, however, has to date prevented wider usage. Diamond-like carbon (DLC) and silicon-incorporated DLC (Si-DLC) coatings are known to provide a high degree of corrosion protection, and hold accordingly promise for enhancing the corrosion resistance of the magnesium alloys. In this work we have studied the effect of coating conditions of DLC coatings as well as Si incorporation into coating on corrosion resistance, deposited onto AZ91 magnesium alloy substrates by plasma based ion implantation (PBII). The influences of a Ti interlayer beneath the DLC, Si-DLC and Ti incorporated DLC (Ti-DLC) coatings fabricated by multi-target direct-current radio-frequency (DC-RF) magnetron sputtering were also examined on both the adhesion strength and corrosion resistance of the materials. We have also examined the effect of the Si content in the Si-DLC coatings made by magnetron sputtering on the alloys' corrosion resistance. The results of potentiodynamic polarization measurements demonstrate that Si-DLC coating deposited by PBII exhibits the highest corrosion resistance in an aqueous 0.05 M NaCl solution. Although Ti layer is helpful in increasing adhesion between DLC coating and AZ91 substrate, it also influences adversely corrosion protection. The ozone treatment of the magnesium alloy's surface before the formation of coatings has been found to improve both adhesion strength and corrosion resistance.

Improvement of corrosion protection property of Mg-alloy by DLC and Si-DLC coatings with PBII technique and multi-target DC-RF magnetron sputtering

Science.gov (United States)

Masami, Ikeyama; Setsuo, Nakao; Tsutomu, Sonoda; Junho, Choi

2009-05-01

Magnesium alloys have been considered as one of the most promising light weight materials with potential applications for automobile and aircraft components. Their poor corrosion resistance, however, has to date prevented wider usage. Diamond-like carbon (DLC) and silicon-incorporated DLC (Si-DLC) coatings are known to provide a high degree of corrosion protection, and hold accordingly promise for enhancing the corrosion resistance of the magnesium alloys. In this work we have studied the effect of coating conditions of DLC coatings as well as Si incorporation into coating on corrosion resistance, deposited onto AZ91 magnesium alloy substrates by plasma based ion implantation (PBII). The influences of a Ti interlayer beneath the DLC, Si-DLC and Ti incorporated DLC (Ti-DLC) coatings fabricated by multi-target direct-current radio-frequency (DC-RF) magnetron sputtering were also examined on both the adhesion strength and corrosion resistance of the materials. We have also examined the effect of the Si content in the Si-DLC coatings made by magnetron sputtering on the alloys' corrosion resistance. The results of potentiodynamic polarization measurements demonstrate that Si-DLC coating deposited by PBII exhibits the highest corrosion resistance in an aqueous 0.05 M NaCl solution. Although Ti layer is helpful in increasing adhesion between DLC coating and AZ91 substrate, it also influences adversely corrosion protection. The ozone treatment of the magnesium alloy's surface before the formation of coatings has been found to improve both adhesion strength and corrosion resistance.

Corrosion and corrosion control

International Nuclear Information System (INIS)

Khanna, A.S.; Totlani, M.K.

1995-01-01

Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

Science.gov (United States)

Danford, M. D.

1994-01-01

The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

Proposed Guidelines for Selection of Methods for Erosion-corrosion Testing in Flowing Liquids

International Nuclear Information System (INIS)

Matsumura, Masanobu

2007-01-01

The corrosion of metals and alloys in flowing liquids can be classified into uniform corrosion and localized corrosion which may be categorized as follows. (1) Localized corrosion of the erosion-corrosion type: the protective oxide layer is assumed to be removed from the metal surface by shear stress or turbulence of the fluid flow. A macro-cell may be defined as a situation in which the bare surface is the macro-anode and the other surface covered with the oxide layer is the macro-cathode. (2) Localized corrosion of the differential flow-velocity corrosion type: at a location of lower fluid velocity, a thin and coarse oxide layer with poor protective qualities may be produced because of an insufficient supply of oxygen. A macro-cell may be defined as a situation in which this surface is the macro-anode and the other surface covered witha dense and stable oxide layer is the macro-cathode. (3) Localized corrosion of the active/passive-cell type: on a metal surface a macro-cell may be defined as a situation in which a part of it is in a passivation state and another in an active dissolution state. This situation may arise from differences in temperature as well as in the supply of the dissolved oxygen. Compared to uniform corrosion, localized corrosion tends to involve a higher wall thinning rate (corrosion rate) due to the macro-cell current as well as to the ratio of the surface area of the macro-anode to that of the macro-cathode, which may be rationalized using potential vs. current density diagrams. The three types of localized corrosion described above can be reproduced in a Jet-in-slit test by changing the flow direction of the test liquid and arranging environmental conditions in an appropriate manner

Eelectrochemical properties and corrosion resistance of carbon-ion-implanted magnesium

International Nuclear Information System (INIS)

Xu, Ruizhen; Yang, Xiongbo; Li, Penghui; Suen, Kai Wong; Wu, Guosong; Chu, Paul K.

2014-01-01

Highlights: • Carbon, as a biocompatible benign element, was implanted into Mg. • A protective amorphous carbon layer was formed after implantation. • Treated sample exhibits good corrosion resistance in two solutions. - Abstract: The corrosion resistance of magnesium-based biomaterials is critical to clinical applications. In this work, carbon as a biocompatible and benign nonmetallic element with high chemical inertness is implanted into pure magnesium to improve the corrosion behavior. X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and Raman scattering reveal the formation of an amorphous carbon layer after ion implantation. Electrochemical studies demonstrate remarkable improvement in the corrosion resistance of magnesium in simulated body fluids (SBF) and Dulbecco’s Modified Eagle Medium (DMEM)

Corrosion processes on weathering steel railway bridge in Prague

OpenAIRE

Urban, Viktor; Křivý, Vít; Buchta, Vojtěch

2016-01-01

This contribution deals with experimental corrosion tests carried out on the weathering steel railway bridge in Prague. The basic specific property of the weathering steel is an ability to create in favourable environment a protective patina layer on its surface. Since 1968 weathering steel is used under the name “Atmofix” in the Czech Republic and can be used as a standard structural material without any corrosion protection. The weathering steel Atmofix is mostly used for bridge structures ...

Corrosion processes of physical vapor deposition-coated metallic implants.

Science.gov (United States)

Antunes, Renato Altobelli; de Oliveira, Mara Cristina Lopes

2009-01-01

Protecting metallic implants from the harsh environment of physiological fluids is essential to guaranteeing successful long-term use in a patient's body. Chemical degradation may lead to the failure of an implant device in two different ways. First, metal ions may cause inflammatory reactions in the tissues surrounding the implant and, in extreme cases, these reactions may inflict acute pain on the patient and lead to loosening of the device. Therefore, increasing wear strength is beneficial to the performance of the metallic implant. Second, localized corrosion processes contribute to the nucleation of fatigue cracks, and corrosion fatigue is the main reason for the mechanical failure of metallic implants. Common biomedical alloys such as stainless steel, cobalt-chrome alloys, and titanium alloys are prone to at least one of these problems. Vapor-deposited hard coatings act directly to improve corrosion, wear, and fatigue resistances of metallic materials. The effectiveness of the corrosion protection is strongly related to the structure of the physical vapor deposition layer. The aim of this paper is to present a comprehensive review of the correlation between the structure of physical vapor deposition layers and the corrosion properties of metallic implants.

Protective effect of KhOSP-10 inhibitor during corrosion, hydrogenadsorption and corrosion cracking of a steel in sulfuric acid

Energy Technology Data Exchange (ETDEWEB)

Mindyuk, A K; Svist, E I; Savitskaya, O P; Goyan, E B; Gopanenko, A N [AN Ukrainskoj SSR, Lvov. Fiziko-Mekhanicheskij Inst.

1975-01-01

The protective propeties of inhibitor KhOSP-10 in the time of corrosion and corrosive cracking of steel 40Kh are higher then those of inhibitors KPI-1, KI-1, I-I-V etc. Its ability to reduce steel hydrogenation is the same as in the case of KPI-1 inhibitor i.e. below that of KI-1. HCl additives enhance the efficiency of inhibitors KPI-1, KI-1, I-1-V etc. up to the protective ability of KhOSP-10. Kinetics of the electrode processes was estimated from polarization curves.

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.

Factors affecting the corrosion of SiC layer by fission product palladium

International Nuclear Information System (INIS)

Dewita, E.

2000-01-01

HTR is one of the advanced nuclear reactors which has inherent safety system, graphite moderated and helium gas cooled. In general, these reactors are designed with the TRISO coated particle consist of four coating layers that are porous pyrolytic carbon (PyC). inner dense PyC (IPyC), silicon carbide (SiC), and outer dense PyC (OPyC). Among the four coating layers, the SiC plays an important role beside in retaining metallic fission products, it also provides mechanical strength to fuel particle. However, results of post irradiation examination indicate that fission product palladium can react with and corrode SiC layer, This assessment is conducted to get the comprehension about resistance of SiC layer on irradiation effects, especially in order to increase the fuel bum-up. The result of this shows that the corrosion of SiC layer by fission product palladium is beside depend on the material characteristics of SiC, and also there are other factors that affect on the SiC layer corrosion. Fuel enrichment, bum-up, and irradiation time effect on the palladium flux in fuel kernel. While, the fuel density, vapour pressure of palladium (the degree depend on the irradiation temperature and kernel composition) effect on palladium migration in fuel particle. (author)

Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

Science.gov (United States)

Xu, Jiang; Zhuo, Chengzhi; Tao, Jie; Jiang, Shuyun; Liu, Linlin

2009-01-01

In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 °C) conditions, amorphous nano-SiO2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical

Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

Science.gov (United States)

Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei

2017-05-01

Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO3 LDHs, Zn-Al-Cl LDHs and Zn-Al-VOx LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VOx LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

Corrosion and protection of uranium alloy penetrators

International Nuclear Information System (INIS)

Weirick, L.J.; Johnson, H.R.; Dini, J.W.

1975-06-01

Penetrators made from either a U--3/4 percent Ti alloy or a U--3/4 percent Mo--3/4 percent Zr--3/4 percent Nb--1/2 percent Ti alloy (''Quad'') corrode mildly in moist air, significantly in moist nitrogen, and severely in salt fog. Adequate protection was provided in moist air and nitrogen by coating with electroplated nickel, electroplated nickel and zinc with a chromate finish, and galvanized zinc with a chromate finish. In salt fog, electroplated nickel offered only temporary protection whereas galvanized zinc and electroplated nickel-zinc provided long-lasting protection. The resistance of uncoated penetrators was affected variously by dissimilar metal couplings. Aluminum protected the Quad alloy and adversely affected the U--3/4 percent Ti alloy, whereas steel enhanced localized corrosion in both. (U.S.)

The influence of time-variable cathodic corrosion protection on a.c. corrosion; Einfluss von zeitlich variierendem kathodischem Korrosionsschutz auf die Wechselstromkorrosion

Energy Technology Data Exchange (ETDEWEB)

Buechler, Markus; Voute, Carl-Heinz; Joos, David [SGK Schweizerische Gesellschaft fuer Korrosionsschutz, Zuerich (Switzerland)

2011-07-01

The current limiting values for corrosion of pipelines under a.c. current stress may be difficult to apply to pipelines, owing to the very heterogeneous bedding of the pipeline, poor jacket quality, or high short-term a.c. voltages. In principle, periodic alternation between very high and very low protective currents may optimize cathodic corrosion protection. This pulsed current strategy was found to be effective in laboratory tests if the operating parameters are set accurately.

Hydrogen–argon plasma pre-treatment for improving the anti-corrosion properties of thin Al2O3 films deposited using atomic layer deposition on steel

International Nuclear Information System (INIS)

Härkönen, Emma; Potts, Stephen E.; Kessels, Wilhelmus M.M.; Díaz, Belén; Seyeux, Antoine; Światowska, Jolanta; Maurice, Vincent; Marcus, Philippe; Radnóczi, György; Tóth, Lajos; Kariniemi, Maarit; Niinistö, Jaakko; Ritala, Mikko

2013-01-01

The effect of H 2 –Ar plasma pre-treatment prior to thermal atomic layer deposition (ALD) and plasma-enhanced atomic layer deposition (PEALD) of Al 2 O 3 films on steel for corrosion protection was investigated. Time-of-flight secondary ion mass spectrometry and transmission electron microscopy were used to observe the changes in the interface. The electrochemical properties of the samples were studied with polarization measurements, and the coating porosities were calculated from the polarization results for easier comparison of the coatings. Prior to thermal ALD the plasma pre-treatment was observed to reduce the amount of impurities at the interface and coating porosity by 1–3 orders of magnitude. The anti-corrosion properties of the PEALD coatings could also be improved by the pre-treatment. However, exposure of the pre-treatment plasma activated steel surface to oxygen plasma species in PEALD led to facile oxide layer formation in the interface. The oxide layer formed this way was thicker than the native oxide layer and appeared to be detrimental to the protective properties of the coating. The best performance for PEALD Al 2 O 3 coatings was achieved when, after the plasma pre-treatment, the surface was given time to regrow a thin protective interfacial oxide prior to exposure to the oxygen plasma. The different effects that thermal and plasma-enhanced ALD have on the substrate-coating interface were compared. The reactivity of the oxygen precursor was shown to have a significant influence on substrate surface in the early stages of film growth and thereafter also on the overall quality of the protective film. - Highlights: • Influence of H 2 –Ar plasma pre-treatment to ALD coatings on steel was studied. • The pre-treatment modified the coating–substrate interface composition and thickness. • The pre-treatment improved the barrier properties of the coatings

Experiencies of corrosion and corrosion protection in seawater-cooling systems in the Nordic countries

International Nuclear Information System (INIS)

Henriksson, S.

1984-10-01

This report summarizes the experience of the corrosion resistance of pumps, heat exchangers, valves, and pipings in different seawater-cooling system. For pumps and heat exchangers the experience has been so extensive that a clear picture of todays status can be given. Owing to more scanty data concerning valves and pipes the survey of the corrosion in these components is less well substantiated. The most common pumps in the cooling systems of power stations are vertically extended shaft pumps. To counteract corrosion on column and casing with organic surface coating and on stainless steel shafts and impellers under shutdown conditions, these should be provided with internal and external cathodic protection. The experience of tin and aluminium bronzes in impellers and shafts in such pumps has been so poor - erosion and cavitaion damage - that a change has usually been made to preferentially ferritic-austenitic Mo-alloyd stainless steels. The combination of stainless steel/Ni-Resist 2 D has been found unsatisfactory owing to the occurrence of galvanic corrosion on the latter material. For heat exchangers, titanium has proved to be far and away the best choice. In the optimal blanket solution for a titanium heat exchangers the tubes are seal-welded to tube sheets of explosion-bonded titanium clad steel. For retubing of old condensers a similar procedure with tubes of high-alloy stainless steel in tube sheets of stainless clad steel is of economic interest. The effect of chlorination of the cooling water, however, remains to be clarified before such a procedure can be unreservedly recommended. Pipings of rubber-lined carbon steel or with thick coatings of solvent-free opoxy resin have shown very good corrosion resistance. Tar-epoxy-resin-coated pipes, however, should usually be provided with internal cathodic protection. Cement-lined carbon steel pipes are used with varying results in the offshore industry. Recently, however, pipes of the high slloy stainless steel

Formation and Role of Gel Fractions in the Corrosion Layer of Zirconium Cladding as the First-stage Protection of the Nuclear Power Plant Fuel

Czech Academy of Sciences Publication Activity Database

Weishauptová, Zuzana; Vrtílková, V.; Bláhová, O.; Maixner, J.

-, č. 16 (2007), s. 29-38 ISSN 1214-9691 R&D Projects: GA ČR GA106/04/0043 Institutional research plan: CEZ:AV0Z30460519 Keywords : zirconium alloys * corrosion layer * hydrated ZrO2 Subject RIV: CF - Physical ; Theoretical Chemistry

Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere

Science.gov (United States)

Li, Dong-liang; Fu, Gui-qin; Zhu, Miao-yong; Li, Qing; Yin, Cheng-xiang

2018-03-01

The corrosion resistance of weathering bridge steels containing conventional contents of Ni (0.20wt%, 0.42wt%, 1.50wt%) and a higher content of Ni (3.55wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low (≤0.42wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher ( 3.55wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe2O2 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42wt% to 1.50wt%, the corrosion resistance of the bridge steel increased only slightly.

Improved mechanical and corrosion properties of nickel composite coatings by incorporation of layered silicates

Energy Technology Data Exchange (ETDEWEB)

Tientong, J. [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States); Ahmad, Y.H. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Nar, M.; D' Souza, N. [University of North Texas, Department of Mechanical and Energy Engineering, Denton, TX 76207 (United States); Mohamed, A.M.A. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Golden, T.D., E-mail: tgolden@unt.edu [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States)

2014-05-01

Layered silicates as exfoliated montmorillonite are incorporated into nickel films by electrodeposition, enhancing both corrosion resistance and hardness. Films were deposited onto stainless steel from a plating solution adjusted to pH 9 containing nickel sulfate, sodium citrate, and various concentrations of exfoliated montmorillonite. The presence of the incorporated layered silicate was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composite films were also compact and smooth like the pure nickel films deposited under the same conditions as shown by scanning electron microscopy. X-ray diffraction results showed that incorporation of layered silicates into the film do not affect the nickel crystalline fcc structure. The nanocomposite films exhibited improved stability and adhesion. Pure nickel films cracked and peeled from the substrate when immersed in 3.5% NaCl solution within 5 days, while the nanocomposite films remained attached even after 25 days. The corrosion resistance of the nickel nanocomposites was also improved compared to nickel films. Nickel-layered silicate composites showed a 25% increase in Young's modulus and a 20% increase in hardness over pure nickel films. - Highlights: • 0.05–2% of layered silicates are incorporated into crystalline nickel films. • Resulting composite films had improved stability and adhesion. • Corrosion resistance improved for the composite films. • Hardness improved 20% and young's modulus improved 25% for the composite films.

Corrosion performance of some titanium-based hard coatings

International Nuclear Information System (INIS)

Matthes, B.; Broszeit, E.; Aromaa, J.; Ronkainen, H.; Hannula, S.P.; Leyland, A.; Matthews, A.

1991-01-01

Tools and machine parts which could benefit from wear-resistant titanium-based hard films are often subject to corrosive environments. Physically vapour-deposited coatings frequently exhibit porosity and even small defects, which can cause rapid local corrosion of the substrate material; there is therefore a requirement for dense and chemically inert coatings. This paper presents corrosion data for titanium-based hard coatings such as TiN, (Ti, Al)N, Ti(B, N) and TiB 2 and also for multilayered structures where additional aluminium-based insulating surface layers (AlN and Al 2 O 3 ) were deposited. The corrosion resistance and porosity of the films were analysed by electrochemical techniques. The degree of metallic bonding can play a significant role in influencing the corrosion resistance of refractory transition-metal-based ceramic coatings. Here we demonstrate that, under potentiodynamic corrosion test conditions, resistance to corrosive attack was relatively poor for TiB 2 , better for (Ti, Al)N and Ti(B, N) and best for TiN. It is also shown that applying the additional protective aluminium-based insulating surface layers on the coating can further improve corrosion resistance. (orig.)

Corrosion protected reversing heat exchanger

International Nuclear Information System (INIS)

Zawierucha, R.

1984-01-01

A reversing heat exchanger of the plate and fin type having multiple aluminum parting sheets in a stacked arrangement with corrugated fins separating the sheets to form multiple flow paths, means for closing the ends of the sheets, an input manifold arrangement of headers for the warm end of of the exchanger and an output manifold arrangement for the cold end of the exchanger with the input air feed stream header and the waste gas exhaust header having an alloy of zinc and aluminum coated on the inside surface for providing corrosion protection to the stack

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

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.

Some Clarifications Regarding Literature on Atmospheric Corrosion of Weathering Steels

Directory of Open Access Journals (Sweden)

I. Díaz

2012-01-01

Full Text Available Extensive research work has thrown light on the requisites for a protective rust layer to form on weathering steels (WSs in the atmosphere, one of the most important is the existence of wet/dry cycling. However, the abundant literature on WS behaviour in different atmospheres can sometimes be confusing and lacks clear criteria regarding certain aspects that are addressed in the present paper. What corrosion models best fit the obtained data? How long does it take for the rust layer to stabilize? What is the morphology and structure of the protective rust layer? What is an acceptable corrosion rate for unpainted WS? What are the guideline environmental conditions, time of wetness (TOW, SO2, and Cl−, for unpainted WS? The paper makes a review of the bibliography on this issue.

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.

In-situ reduced graphene oxide-polyvinyl alcohol composite coatings as protective layers on magnesium substrates

Directory of Open Access Journals (Sweden)

Xingkai Zhang

2017-06-01

Full Text Available A simple and feasible method was developed to fabricate in-situ reduced graphene oxide-polyvinyl alcohol composite (GO-PVA coatings as protective layers on magnesium substrates. Polyvinyl alcohol was used as an in-situ reductant to transform GO into reduced GO. Contiguous and uniform GO-PVA coatings were prepared on magnesium substrates by dip-coating method, and were further thermally treated at 120 °C under ambient condition to obtain in-situ reduced GO-PVA coatings. Owing to the reducing effect of PVA, thermal treatment at low temperature led to effective in-situ reduction of GO as confirmed by XRD, Raman, FTIR and XPS tests. The corrosion current density of magnesium substrates in 3.5 wt% NaCl solution could be lowered to its 1/25 when using in-situ reduced GO-PVA coatings as protective layers.

Inhibition study of additives towards the corrosion of ferrous metal in palm biodiesel

International Nuclear Information System (INIS)

Fazal, M.A.; Sazzad, B.S.; Haseeb, A.S.M.A.; Masjuki, H.H.

2016-01-01

Highlights: • TBA doped biodiesel exhibits fairly good corrosion inhibition efficiency. • TBA forms nitrogen-containing layer on metal surface and protects the corrosion. • Materials exposed to TBA doped biodiesel show less surface roughness. - Abstract: Some efforts have already been given by other researchers to characterize the corrosion behavior of different metals in biodiesel. However, there is very limited information on its remedial measure. Therefore, this study investigates the effects of tert-butylamine (TBA), benzotriazole (BTA), butylate-dhydroxytoluene (BHT), and pyrogallol (PY) on the corrosion of cast iron (CI) and low carbon steel (LCS) through an immersion test in palm biodiesel (B100) at 300 K. Result shows that TBA-doped biodiesel exhibits fairly good corrosion-inhibiting properties for materials exposed to B100. Inhibition efficiency of TBA is found to be 86.54% and 86.71% for CI and LCS, respectively which is far better than other tested additives in this study. The high inhibition efficiency could be attributed to the dominant physical adsorption of N-containing compound which creates a protective layer over the metal surface and prevents corrosion.

Use of Extracted Green Inhibitors as a Friendly Choice in Corrosion Protection of Low Alloy Carbon Steel

Directory of Open Access Journals (Sweden)

Jano, A.

2012-11-01

Full Text Available Mitigation of corrosion impact on environment is an important step in environmental protection. Use of environmentally friendly corrosion protection methods is very important. It is smart to choose cheap and safe to handle compounds as corrosion inhibitors. The use of green inhibitors (extracted inexpensively, from the seed endosperm of some Leguminosae plants, and investigation of their efficiency in corrosion protection is the aim of this study. As green inhibitor one kind of polysaccharides (galactomannan from locust bean gum (also known as carob gum, carob bean gum extracted from the seed of carob tree is used. Corrosion protection efficiency of these extracted green inhibitors was tested for carbon steel marked as: steel 39, steel 44, and iron B 500 (usually applied as reinforcing bars to concrete. Sulfuric acid solution in the presence of chloride ions was used as corrosion media. The composition of corrosion acid media used was 1 mol L-1 H2SO4 and 10-3 mol L-1 Cl- (in the form of NaCl. Electrochemical techniques such as potentiodynamic polarization methods were used for inhibitor efficiency testing.

Analysis of corrosion layers in ancient Roman silver coins with high resolution surface spectroscopic techniques

International Nuclear Information System (INIS)

Keturakis, Christopher J.; Notis, Ben; Blenheim, Alex; Miller, Alfred C.; Pafchek, Rob; Notis, Michael R.; Wachs, Israel E.

2016-01-01

Highlights: • Five ancient silver alloy coins (225 BCE–244 CE) were analyzed using surface characterization techniques. • Both destructive and non-destructive surface characterization methods were developed. • Alloying with copper, even in small amounts, leads to the formation of an outer Cu 2 O corrosion layer. - Abstract: Determination of the microchemistry of surface corrosion layers on ancient silver alloy coins is important both in terms of understanding the nature of archaeological environmental conditions to which these ancient coins were exposed and also to help in their conservation. In this present study, five ancient silver alloy coins (225 BCE–244 CE) were used as test vehicles to measure their immediate surface microchemistry and evaluate the appropriateness and limitations of High Sensitivity-Low Energy Ion Scattering Spectroscopy (HS-LEIS, 0.3 nm depth analysis), High Resolution-X-ray Photoelectron Spectroscopy (HR-XPS, 1–3 nm depth analysis) and High Resolution-Raman Spectroscopy (HR-Raman, ∼1000 nm depth analysis). Additional information about the deeper corrosion layers, up to ∼300–1000 nm, was provided by dynamic HS-LEIS and HR-Raman spectroscopy. While not archeologically significant, the use of these coins of small commercial value provides data that is more representative of the weaker signals typically obtained from ancient corroded objects, which can be in stark contrast to pristine data often obtained from carefully prepared alloys of known composition. The oldest coins, from 225 to 214 BCE, possessed an outermost surface layer containing Cu 2 O, Na, Al, Pb, and adsorbed hydrocarbons, while the more recent coins, from 98 to 244 CE, contained Cu 2 O, Ag, N, F, Na, Al, S, Cl, and adsorbed hydrocarbons in similar corresponding surface layers. It thus appears that alloying with copper, even in small amounts, leads to the formation of an outer Cu 2 O layer. Depth profiling revealed the presence of K, Na, Cl, and S as key

In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films

Directory of Open Access Journals (Sweden)

Junsheng Wu

2017-04-01

Full Text Available A layered double hydroxide (LDH film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM. The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS, scanning electrochemical microscopy (SECM, and a salt-spray test (SST.The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film.

Corrosion, haemocompatibility and bacterial adhesion behaviour of ...

Indian Academy of Sciences (India)

Abstract. TiZrN coating was deposited on 316L stainless steel (SS) by the reactive magnetron co-sputtering tech- nique. .... Uncoated 316L SS exhibited poor corrosion protection ... depletion of native oxide layer present on uncoated substrate.

Fabrication of anticorrosive multilayer onto magnesium alloy substrates via spin-assisted layer-by-layer technique

Energy Technology Data Exchange (ETDEWEB)

Cai Kaiyong, E-mail: Kaiyong_cai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Sui Xiaojing; Hu Yan [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Zhao Li [China National Centre for Biotechnology Development, No. 16, Xi Si Huan Zhong Lu, Haidian District, Beijing 100036 (China); Lai Min; Luo Zhong; Liu Peng; Yang Weihu [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

2011-12-01

To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: {yields} Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. {yields} The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. {yields} The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.

Fabrication of anticorrosive multilayer onto magnesium alloy substrates via spin-assisted layer-by-layer technique

International Nuclear Information System (INIS)

Cai Kaiyong; Sui Xiaojing; Hu Yan; Zhao Li; Lai Min; Luo Zhong; Liu Peng; Yang Weihu

2011-01-01

To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: → Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. → The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. → The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.

High Temperature Corrosion under Laboratory Conditions Simulating Biomass-Firing: A Comprehensive Characterization of Corrosion Products

DEFF Research Database (Denmark)

Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

2014-01-01

characterization of the corrosion products. The corrosion products consisted of three layers: i) the outermost layer consisting of a mixed layer of K2SO4 and FexOy on a partly molten layer of the initial deposit, ii) the middle layer consists of spinel (FeCr2O4) and Fe2O3, and iii) the innermost layer is a sponge......-like Ni3S2 containing layer. At the corrosion front, Cl-rich protrusions were observed. Results indicate that selective corrosion of Fe and Cr by Cl, active oxidation and sulphidation attack of Ni are possible corrosion mechanisms....

Influence of preoxidation on high temperature corrosion of a Ni-based alloy under conditions relevant to biomass firing

DEFF Research Database (Denmark)

Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

2017-01-01

. Complementary characterization methods were employed to study samples after preoxidation as well as after corrosion exposure. The oxides obtained by the preoxidation treatments protected the alloy during corrosion exposure at 560 °C for a period of 168 h. In contrast, non-preoxidized samples suffered corrosion...... attack and formed porous non-protective oxides containing the alloying elements, Ni, Cr, Ti and Al. The influence of the preoxidation layers on the corrosion mechanism is discussed....

Scratch, wear and corrosion resistant organic inorganic hybrid materials for metals protection and barrier

International Nuclear Information System (INIS)

Barletta, M.; Gisario, A.; Puopolo, M.; Vesco, S.

2015-01-01

Highlights: • Polysiloxane coatings as protective barriers to delay erosion/corrosion of Fe 430 B metal substrates. • Methyl groups feature a very small steric hindrance and confer ductility to the Si–O–Si backbone. • Phenyl groups feature a larger steric hindrance, but they ensure stability and high chemical inertness. • Remarkable adhesion to the substrate, good scratch resistance and high wear endurance. • Innovative ways to design of long lasting protective barriers against corrosion and aggressive chemicals. - Abstract: Polysiloxanes are widely used as protective barriers to delay erosion/corrosion and increase chemical inertness of metal substrates. In the present work, a high molecular weight methyl phenyl polysiloxane resin was designed to manufacture a protective coating for Fe 430 B structural steel. Methyl groups feature very small steric hindrance and confer ductility to the Si–O–Si backbone of the organic inorganic hybrid resin, thus allowing the achievement of high thickness. Phenyl groups feature larger steric hindrance, but they ensure stability and high chemical inertness. Visual appearance and morphology of the coatings were studied by field emission scanning electron microscopy and contact gauge surface profilometry. Micro-mechanical response of the coatings was analyzed by instrumented progressive load scratch, while wear resistance by dry sliding linear reciprocating tribological tests. Lastly, chemical inertness and corrosion endurance of the coatings were evaluated by linear sweep voltammetry and chronoamperometry in aggressive acid environment. The resulting resins yielded protective materials, which feature remarkable adhesion to the substrate, good scratch resistance and high wear endurance, thus laying the foundations to manufacture long lasting protective barriers against corrosion and, more in general, against aggressive chemicals

Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

International Nuclear Information System (INIS)

Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei

2017-01-01

Highlights: • Zn-Al LDHs film loaded nitrate anions has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method. • The Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs film were obtained based on anion-exchange mechanism. • The Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs film could effectively protect magnesium alloy. - Abstract: Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO_3 LDHs, Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

Energy Technology Data Exchange (ETDEWEB)

Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei, E-mail: kwgao@yahoo.com

2017-05-15

Highlights: • Zn-Al LDHs film loaded nitrate anions has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method. • The Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs film were obtained based on anion-exchange mechanism. • The Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs film could effectively protect magnesium alloy. - Abstract: Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO{sub 3} LDHs, Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

Corrosion and cathodic protection of buried pipes: study, simulation and application of solar energy

International Nuclear Information System (INIS)

Laoun, Brahim; Serir, Lazhar; Niboucha, Karima

2006-01-01

Cathodic protection is intensively used on steel pipes in petroleum and gas industries. It is a technique used to prevent corrosion which transforms the whole pipe into a cathode of a corrosion cell. Two types of cathodic protection systems are usually used: 1) the galvanic protection systems which use galvanic anodes, also called sacrificial anodes being electrochemically more electronegative than the structure to be protected and 2) the imposed current systems, which through a current generator will deliver a direct current from the anode to the structure to be protected. The aim of this work is to design a cathodic protection system of a pipe by imposed current with auxiliary electric solar energy. (O.M.)

Corrosion resistant surface for vanadium nitride and hafnium nitride layers as function of grain size

Science.gov (United States)

Escobar, C. A.; Caicedo, J. C.; Aperador, W.

2014-01-01

In this research it was studied vanadium nitride (VN) and hafnium nitride (HfN) film, which were deposited onto silicon (Si (100)) and AISI 4140 steel substrates via r.f. magnetron sputtering technique in Ar/N2 atmosphere with purity at 99.99% for both V and Hf metallic targets. Both films were approximately 1.2±0.1 μm thick. The crystallography structures that were evaluated via X-ray diffraction analysis (XRD) showed preferential orientations in the Bragg planes VN (200) and HfN (111). The chemical compositions for both films were characterized by EDX. Atomic Force Microscopy (AFM) was used to study the morphology; the results reveal grain sizes of 78±2 nm for VN and 58±2 nm for HfN and roughness values of 4.2±0.1 nm for VN and 1.5±0.1 nm for HfN films. The electrochemical performance in VN and HfN films deposited onto steel 4140 were studied by Tafel polarization curves and impedance spectroscopy methods (EIS) under contact with sodium chloride at 3.5 wt% solution, therefore, it was found that the corrosion rate decreased about 95% in VN and 99% for HfN films in relation to uncoated 4140 steel, thus demonstrating, the protecting effect of VN and HfN films under a corrosive environment as function of morphological characteristics (grain size). VN(grain size)=78±2.0 nm, VN(roughness)=4.2±0.1 nm, VN(corrosion rate)=40.87 μmy. HfN(grain size)=58±2.0 nm, HfN(roughness)=1.5±0.1 nm, HfN(corrosion rate)=0.205 μmy. It was possible to analyze that films with larger grain size, can be observed smaller grain boundary thus generating a higher corrosion rate, therefore, in this work it was found that the HfN layer has better corrosion resistance (low corrosion rate) in relation to VN film which presents a larger grain size, indicating that the low grain boundary in (VN films) does not restrict movement of the Cl- ion and in this way the corrosion rate increases dramatically.

Significant Corrosion Resistance in an Ultrafine-Grained Al6063 Alloy with a Bimodal Grain-Size Distribution through a Self-Anodic Protection Mechanism

Directory of Open Access Journals (Sweden)

Mahdieh Shakoori Oskooie

2016-12-01

Full Text Available The bimodal microstructures of Al6063 consisting of 15, 30, and 45 vol. % coarse-grained (CG bands within the ultrafine-grained (UFG matrix were synthesized via blending of high-energy mechanically milled powders with unmilled powders followed by hot powder extrusion. The corrosion behavior of the bimodal specimens was assessed by means of polarization, steady-state cyclic polarization and impedance tests, whereas their microstructural features and corrosion products were examined using optical microscopy (OM, scanning transmission electron microscopy (STEM, field emission scanning electron microscopy (FE-SEM, electron backscattered diffraction (EBSD, energy dispersive spectroscopy (EDS, and X-ray diffraction (XRD techniques. The bimodal Al6063 containing 15 vol. % CG phase exhibits the highest corrosion resistance among the bimodal microstructures and even superior electrochemical behavior compared with the plain UFG and CG materials in the 3.5% NaCl solution. The enhanced corrosion resistance is attributed to the optimum cathode to anode surface area ratio that gives rise to the formation of an effective galvanic couple between CG areas and the UFG matrix. The operational galvanic coupling leads to the domination of a “self-anodic protection system” on bimodal microstructure and consequently forms a uniform thick protective passive layer over it. In contrast, the 45 vol. % CG bimodal specimen shows the least corrosion resistance due to the catastrophic galvanic corrosion in UFG regions. The observed results for UFG Al6063 suggest that metallurgical tailoring of the grain structure in terms of bimodal microstructures leads to simultaneous enhancement in the electrochemical behavior and mechanical properties of passivable alloys that are usually inversely correlated. The mechanism of self-anodic protection for passivable metals with bimodal microstructures is discussed here for the first time.

Effect of corrosion product layer on SCC susceptibility of copper containing type 304 stainless steel in 1 M H2SO4

International Nuclear Information System (INIS)

Asawa, M.; Devasenapathi, A.; Fujisawa, M.

2004-01-01

The effect of surface corrosion product layer on the stress corrosion cracking (SCC) susceptibility of type 304 stainless steel with Cu was studied in 1 kmol/m 3 (1 M) sulfuric acid at 353 K temperature. Studies based on the intermittent removal of surface corrosion product layer indicated that the surface film governs the SCC behavior of the alloy by accelerating both the crack initiation and propagation stages. The electrochemical impedance and polarization studies showed the surface layer to be promoting SCC initiation by lowering the uniform corrosion rate and the propagation by shifting the surface corrosion potential to a more noble direction. The elemental analysis of the corrosion product both by the energy dispersive X-ray (EDX) spectroscopy and by X-ray diffraction (XRD) analysis along with the thermodynamic calculations showed the layer to be constituted mainly of metallic copper (Cu) and the mono-hydrated iron sulfate which acts as cathode promoting SCC

Development of new corrosion inhibitor tested on mild steel supported by electrochemical study

Science.gov (United States)

Habeeb, Hussein Jwad; Luaibi, Hasan Mohammed; Dakhil, Rifaat Mohammed; Kadhum, Abdul Amir H.; Al-Amiery, Ahmed A.; Gaaz, Tayser Sumer

2018-03-01

Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol have been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution (HCl) using electrochemical measurements test includes PD (Potentiodynamic), EIS (Electrochemical impedance spectroscopy), OCP (Open circuit potential) and EFM (electrochemical frequency modulation). The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol corrosion inhibitors are effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases.

Dictionary corrosion and corrosion control

International Nuclear Information System (INIS)

1985-01-01

This dictionary has 13000 entries in both languages. Keywords and extensive accompanying information simplify the choice of word for the user. The following topics are covered: Theoretical principles of corrosion; Corrosion of the metals and alloys most frequently used in engineering. Types of corrosion - (chemical-, electro-chemical, biological corrosion); forms of corrosion (superficial, pitting, selective, intercrystalline and stress corrosion; vibrational corrosion cracking); erosion and cavitation. Methods of corrosion control (material selection, temporary corrosion protection media, paint and plastics coatings, electro-chemical coatings, corrosion prevention by treatment of the corrosive media); Corrosion testing methods. (orig./HP) [de

Potassium sorbate-A new aqueous copper corrosion inhibitor

International Nuclear Information System (INIS)

Abelev, Esta; Starosvetsky, David; Ein-Eli, Yair

2007-01-01

This work presents the novel nature of 2,4-hexadienoic acid potassium salt (potassium sorbate (KCH 3 CH=CHCH=CHCO 2 )) as an effective copper aqueous corrosion inhibitor. The influence of pH and potassium sorbate concentration on copper corrosion in aerated sulfate and chloride solutions is reported. Degree of copper protection was found to increase with an increase in potassium sorbate concentration; an optimum concentration of this inhibitor in sulfate solutions was found to be 10 g/L. Copper is highly resistant to corrosion attacks by chloride ions in the presence of potassium sorbate. X-ray photoelectron spectroscopy (XPS) studies suggest that copper protection is achieved via the formation of a mixed layer of cuprous oxide, cupric hydroxide and copper(II)-sorbate at the metal surface

General corrosion of carbon steels in high temperature water

International Nuclear Information System (INIS)

Gras, J.M.

1994-04-01

This short paper seeks to provide a summary of the main knowledge about the general corrosion of carbon steels in high temperature water. In pure water or slightly alkaline deaerated water, steels develop a protective coating of magnetite in a double layer (Potter and Mann oxide) or a single layer (Bloom oxide). The morphology of the oxide layer and the kinetics of corrosion depend on the test parameters controlling the solubility of iron. The parameters exercising the greatest influence are partial hydrogen pressure and mass transfer: hydrogen favours the solubilization of the magnetite; the entrainment of the dissolved iron prevents a redeposition of magnetite on the surface of the steel. Cubic or parabolic in static conditions, the kinetics of corrosion tends to be linear in dynamic conditions. In dynamic operation, corrosion is at least one order of magnitude lower in water with a pH of 10 than in pure water with a pH of 7. The activation energy of corrosion is 130 kJ/mol (31 kcal/mol). This results in the doubling of corrosion at around 300 deg C for a temperature increase of 15 deg C. Present in small quantities (100-200 ppb), oxygen decreases general corrosion but increases the risk of pitting corrosion - even for a low chloride content - and stress corrosion cracking or corrosion-fatigue. The steel composition has probably an influence on the kinetics of corrosion in dynamic conditions; further work would be required to clarify the effect of some residual elements. (author). 31 refs., 9 figs., 2 tabs

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.

Impact of microgalvanic corrosion on the degradation morphology of WE43 and pure magnesium under exposure to simulated body fluid

Energy Technology Data Exchange (ETDEWEB)

Kalb, H., E-mail: Hermann.Kalb@biomed.uni-erlangen.de [Max Schaldach Endowed Professorship for Biomedical Engineering, Center for Medical Physics and Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Henkestrasse 91, Erlangen 91052 (Germany); Rzany, A., E-mail: Alexander.Rzany@biomed.uni-erlangen.de [Max Schaldach Endowed Professorship for Biomedical Engineering, Center for Medical Physics and Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Henkestrasse 91, Erlangen 91052 (Germany); Hensel, B., E-mail: Bernhard.Hensel@biomed.uni-erlangen.de [Max Schaldach Endowed Professorship for Biomedical Engineering, Center for Medical Physics and Technology, Friedrich-Alexander-University Erlangen-Nuremberg, Henkestrasse 91, Erlangen 91052 (Germany)

2012-04-15

Highlights: Black-Right-Pointing-Pointer Localized Corrosion of WE43 and pure magnesium under static exposure to SBF. Black-Right-Pointing-Pointer Vigorous hydrogen evolution at particles, which act as micro-cathodes. Black-Right-Pointing-Pointer Zr at WE43 and Fe at pure magnesium are dominant micro-cathodes. Black-Right-Pointing-Pointer Protection of surrounding bulk and volcano-shaped depositions. Black-Right-Pointing-Pointer A comprehensive corrosion model including a corrosion double-layer is proposed. - Abstract: Corrosion of magnesium alloys was studied during exposure to simulated body fluid (SBF). Microgalvanic processes dominate degradation morphology and formation of the corrosion/conversion layer. Localized corrosion with vigorous hydrogen evolution was observed at zirconium- and iron-rich precipitates that act as micro-cathodes. These are surrounded by volcano-shaped deposits of Mg(OH){sub 2}. Circular areas around cathodic centers were found to be protected from corrosion, while bulk degradation takes place in between. In SBF, conversion to a corrosion double layer was demonstrated. Differences observed for WE43 and pure magnesium (Mg) are discussed within the framework of a comprehensive model of the mechanisms of corrosion.

The Cost Analysis of Corrosion Protection Solutions for Steel Components in Terms of the Object Life Cycle Cost

Directory of Open Access Journals (Sweden)

Kowalski Dariusz

2017-09-01

Full Text Available Steel materials, due to their numerous advantages - high availability, easiness of processing and possibility of almost any shaping are commonly applied in construction for carrying out basic carrier systems and auxiliary structures. However, the major disadvantage of this material is its high corrosion susceptibility, which depends strictly on the local conditions of the facility and the applied type of corrosion protection system. The paper presents an analysis of life cycle costs of structures installed on bridges used in the road lane conditions. Three anti-corrosion protection systems were considered, analyzing their essential cost components. The possibility of reducing significantly the costs associated with anti-corrosion protection at the stage of steel barriers maintenance over a period of 30 years has been indicated. The possibility of using a new approach based on the life cycle cost estimation in the anti-corrosion protection of steel elements is presented. The relationship between the method of steel barrier protection, the scope of repair, renewal work and costs is shown. The article proposes an optimal solution which, while reducing the cost of maintenance of road infrastructure components in the area of corrosion protection, allows to maintain certain safety standards for steel barriers that are installed on the bridge.

The Cost Analysis of Corrosion Protection Solutions for Steel Components in Terms of the Object Life Cycle Cost

Science.gov (United States)

Kowalski, Dariusz; Grzyl, Beata; Kristowski, Adam

2017-09-01

Steel materials, due to their numerous advantages - high availability, easiness of processing and possibility of almost any shaping are commonly applied in construction for carrying out basic carrier systems and auxiliary structures. However, the major disadvantage of this material is its high corrosion susceptibility, which depends strictly on the local conditions of the facility and the applied type of corrosion protection system. The paper presents an analysis of life cycle costs of structures installed on bridges used in the road lane conditions. Three anti-corrosion protection systems were considered, analyzing their essential cost components. The possibility of reducing significantly the costs associated with anti-corrosion protection at the stage of steel barriers maintenance over a period of 30 years has been indicated. The possibility of using a new approach based on the life cycle cost estimation in the anti-corrosion protection of steel elements is presented. The relationship between the method of steel barrier protection, the scope of repair, renewal work and costs is shown. The article proposes an optimal solution which, while reducing the cost of maintenance of road infrastructure components in the area of corrosion protection, allows to maintain certain safety standards for steel barriers that are installed on the bridge.

Evaluation of the protection behaviour of reinforcement steel against corrosion induced by chlorides in reinforced mortar specimens

International Nuclear Information System (INIS)

Crivelaro, Marcos

2002-01-01

In this work various treatments for protecting reinforcing steels against corrosion induced by chlorides have been evaluated. Additives to mortars and surface treatments given to reinforcing steels were evaluated as corrosion protection measures. In the preliminary tests the corrosion resistance of a CA 50 steel treated by immersion in nearly 50 different solutions, was determined. The solutions were prepared with tannins (from various sources) and/or benzotriazole, and during immersion, a surface film formed on the steel. The corrosion resistance of the coated steels was evaluated in a saturated Ca(OH) 2 solution with 5% (wt) NaCl. Preliminary tests were also carried out with mortars reinforced with uncoated steel to which tannin or lignin was added. Two organic coatings, a monocomponent and a bicomponent type, formulated specially for this investigation, with both tannin and benzotriazole, were also tested in the preliminary tests to select the coating with better corrosion protection property. The bicomponent type (epoxy coating) showed better performance than the monocomponent type coating, and the former was therefore chosen to investigate the corrosion performance on CA 50 steel inside mortar specimens. From the preliminary tests, two solutions with tannin from two sources, Black Wattle (Acacia mearnsii) and Brazilian tea (Ilex paraguariensis St. Hill), to which benzotriazole and phosphoric acid were added, were chosen. Mortar specimens reinforced with CA50 steel treated by immersion in these two solutions were prepared. Also, epoxy coated CA50 steel was tested as reinforcement inside mortar specimens. Mortars reinforced with uncoated CA50 steel were also prepared and corrosion tested for comparison. The effect of tannin and lignin as separate additives to the mortar on the corrosion resistance of uncoated steel was also studied. The reinforced mortar specimens were tested with various cycles of immersion for 2 days in 3.5% (wt) NaCl followed by with air

Corrosion fatigue in nitrocarburized quenched and tempered steels

Science.gov (United States)

Khani, M. Karim; Dengel, D.

1996-05-01

In order to investigate the fatigue strength and fracture mechanism of salt bath nitrocarburized steels, specimens of the steels SAE 4135 and SAE 4140, in a quenched and tempered state, and additionally in a salt bath nitrocarburized and oxidizing cooled state as well as in a polished (after the oxidizing cooling) and renewed oxidized state, were subjected to comparative rotating bending fatigue tests in inert oil and 5 pct NaCl solution. In addition, some of the quenched and tempered specimens of SAE 4135 material were provided with an approximately 50-μm-thick electroless Ni-P layer, in order to compare corrosion fatigue behavior between the Ni-P layer and the nitride layers. Long-life corrosion fatigue tests of SAE 4135 material were carried out under small stresses in the long-life range up to 108 cycles with a test frequency of 100 Hz. Fatigue tests of SAE 4140 material were carried out in the range of finite life (low-cycle range) with a test frequency of 13 Hz. The results show that the 5 pct NaCl environment drastically reduced fatigue life, but nitrocarburizing plus oxidation treatment was found to improve the corrosion fatigue life over that of untreated and Ni-P coated specimens. The beneficial effect of nitrocarburizing followed by oxidation treatment on cor-rosion fatigue life results from the protection rendered by the compound layer by means of a well-sealed oxide layer, whereby the pores present in the compound layer fill up with oxides. The role of inclusions in initiating fatigue cracks was investigated. It was found that under corrosion fatigue conditions, the fatigue cracks started at cavities along the interfaces of MnS inclusions and matrix in the case of quenched and tempered specimens. The nitrocarburized specimens, however, showed a superposition of pitting corrosion and corrosion fatigue in which pores and nonmetallic inclusions in the compound layer play a predominant role concerning the formation of pits in the substrate.

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.

The Corrosion Behavior of Stainless Steel 316L in Novel Quaternary Eutectic Molten Salt System

Science.gov (United States)

Wang, Tao; Mantha, Divakar; Reddy, Ramana G.

2017-03-01

In this article, the corrosion behavior of stainless steel 316L in a low melting point novel LiNO3-NaNO3-KNO3-NaNO2 eutectic salt mixture was investigated at 695 K which is considered as thermally stable temperature using electrochemical and isothermal dipping methods. The passive region in the anodic polarization curve indicates the formation of protective oxides layer on the sample surface. After isothermal dipping corrosion experiments, samples were analyzed using SEM and XRD to determine the topography, corrosion products, and scale growth mechanisms. It was found that after long-term immersion in the LiNO3-NaNO3-KNO3-NaNO2 molten salt, LiFeO2, LiFe5O8, Fe3O4, (Fe, Cr)3O4 and (Fe, Ni)3O4 oxides were formed. Among these corrosion products, LiFeO2 formed a dense and protective layer which prevents the SS 316L from severe corrosion.

The effect of zinc thickness on corrosion film breakdown of Colombian galvanized steel

Science.gov (United States)

Sandoval-Amador, A.; E Torres Ramirez, J.; Cabrales-Villamizar, P. A.; Laverde Cataño, D.; Y Peña-Ballesteros, D.

2017-12-01

This work studies the corrosion behaviour of Colombian galvanized steel in solutions of chloride and sulphate ions. The effect of the thickness and exposure time on the film’s breakdown susceptibility and protectiveness of the corrosion products were studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The corrosion products were analysed using SEM-EDS and XRD. The samples with a higher thickness level in the zinc film (Z180) have the lowest corrosion rate. In this case, one of the products that was formed by the chemical reactions that occurred was Zinc hydroxide, which exhibits a passive behaviour as observed in the Pourbaix curves of the obtained potentials and in how the different Ph levels of the solutions worked. The sheets with the highest thickness (Z180) had the best performance, since at the end of the study they showed the least amount of damage on the surface of the zinc layer. This is because the thickness of the zinc layer favours the formation of simonkolleite, which is the corrosion product that protects the material under the conditions of the study.

On the protective effect of KhOSP-10 inhibitor during corrosion, hydrogenadsorption and corrosion cracking of a steel in sulfuric acid

International Nuclear Information System (INIS)

Mindyuk, A.K.; Svist, E.I.; Savitskaya, O.P.; Goyan, E.B.; Gopanenko, A.N.

1975-01-01

The protective propeties of inhibitor KhOSP-10 in the time of corrosion and corrosive cracking of steel 40Kh are higher then those of inhibitors KPI-1, KI-1, I-I-V etc. Its ability to reduce steel hydrogenation is the same as in the case of KPI-1 inhibitor i.e. below that of KI-1. HCl additives enhance the efficiency of inhibitors KPI-1, KI-1, I-1-V etc. up to the protective ability of KhOSP-10. Kinetics of the electrode processes was estimated from polarization curves

Analysis of corrosion layers in ancient Roman silver coins with high resolution surface spectroscopic techniques

Energy Technology Data Exchange (ETDEWEB)

Keturakis, Christopher J. [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Ben [Brandeis University, Waltham, MA 02453 (United States); Blenheim, Alex [Department of Mechanical Engineering, Pennsylvania State University, College Park, PA 16802 (United States); Miller, Alfred C.; Pafchek, Rob [Zettlemoyer Center for Surface Studies, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Michael R., E-mail: mrn1@lehigh.edu [Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Wachs, Israel E., E-mail: iew0@lehigh.edu [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States)

2016-07-15

Highlights: • Five ancient silver alloy coins (225 BCE–244 CE) were analyzed using surface characterization techniques. • Both destructive and non-destructive surface characterization methods were developed. • Alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O corrosion layer. - Abstract: Determination of the microchemistry of surface corrosion layers on ancient silver alloy coins is important both in terms of understanding the nature of archaeological environmental conditions to which these ancient coins were exposed and also to help in their conservation. In this present study, five ancient silver alloy coins (225 BCE–244 CE) were used as test vehicles to measure their immediate surface microchemistry and evaluate the appropriateness and limitations of High Sensitivity-Low Energy Ion Scattering Spectroscopy (HS-LEIS, 0.3 nm depth analysis), High Resolution-X-ray Photoelectron Spectroscopy (HR-XPS, 1–3 nm depth analysis) and High Resolution-Raman Spectroscopy (HR-Raman, ∼1000 nm depth analysis). Additional information about the deeper corrosion layers, up to ∼300–1000 nm, was provided by dynamic HS-LEIS and HR-Raman spectroscopy. While not archeologically significant, the use of these coins of small commercial value provides data that is more representative of the weaker signals typically obtained from ancient corroded objects, which can be in stark contrast to pristine data often obtained from carefully prepared alloys of known composition. The oldest coins, from 225 to 214 BCE, possessed an outermost surface layer containing Cu{sub 2}O, Na, Al, Pb, and adsorbed hydrocarbons, while the more recent coins, from 98 to 244 CE, contained Cu{sub 2}O, Ag, N, F, Na, Al, S, Cl, and adsorbed hydrocarbons in similar corresponding surface layers. It thus appears that alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O layer. Depth profiling revealed the presence of K, Na, Cl, and

Investigation of surface layer on rolled recycled AA5050 in relation to Filiform Corrosion

NARCIS (Netherlands)

2007-01-01

The presence of a heavily deformed surface layer (a few microns thick) on rolled aluminium alloy is understood to be one of the main reasons contributing to the Filiform Corrosion (FFC) susceptibility of the alloy. The surface layer is formed during the thermo-mechanical processing of the sheet

Countermeasures to corrosion on water walls. Part 2; Aatgaerder mot eldstadskorrosion paa panntuber. Etapp 2

Energy Technology Data Exchange (ETDEWEB)

Storesund, Jan; Elger, Ragna; Nordling, Magnus; Viklund, Peter

2011-01-15

Background: The problems with water wall corrosion have been accelerating over the last years. There are a number of reasons for this. Originally mild steels were successfully used in power plant water walls. The magnetite layer that forms at the fire side of the tubes when the boiler is taken into operation protected from corrosion attack. The fuels at that time (oil, coal, gas) were not able to break down the magnetite by corrosion. In addition, there were no restrictions for pollutions and for the combustion itself that could contribute to corrosion attack. The usage of fossil fuels has decreased substantially over the last 25 years, not least by environmental reasons. As a replacement a number of different kinds of bio mass fuels are used. These are typically more or less corrosive and the magnetite layers are attacked. The corrosion is often supported by reducing conditions as a result of the restrictions of the NO{sub x}-pollution. Also the waste fuelled boilers have huge corrosion problems. This has been the case for the last 25 years but nowadays the number of such plants is so much higher and the service data have been turned up. Corrosion protection of the water wall tubes started to be successful in the beginning of the seventies by the introduction of the composite tube. Such tubes are fabricated by mild steel or a low alloy core and corrosion resistant austenite steel or nickel base as an about 2 mm thick corrosion protective coating. Weld cladding of the water wall tubes was introduced in the 1980's as a significantly cheaper alternative to the composite tubes. Thermal spraying and refractory protection are other methods. These corrosion protection methods have not always been effective. For example, depending on incorrect materials selection, incorrect performance and incorrect method selection for the current corrosion or erosion attack. Therefore, there is a need for increased knowledge of which protection method and material that will work

Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

International Nuclear Information System (INIS)

Jo, Duhwan; Kwon, Moonjae; Kim, Jongsang

2012-01-01

Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances

Investigation of parameters governing the corrosion protection efficacy of fusion bonded epoxy coatings

OpenAIRE

Ramniceanu, Andrei

2007-01-01

The primary cause of corrosion in transportation structures is due to chlorides which are applied to bridge decks as deicing salts. The direct cost of corrosion damage to the countryâ s infrastructure is approximately $8.3 billion per year. One of the most common corrosion abatement methods in the United States is the barrier protection implemented through the application of fusion bonded epoxy coatings. The purpose of this study was to investigate various coating and exposure param...

Development of new corrosion inhibitor tested on mild steel supported by electrochemical study

Directory of Open Access Journals (Sweden)

Hussein Jwad Habeeb

2018-03-01

Full Text Available Mild steel is a metal which is commonly used in industrials and manufacturing of equipment for most industries round the world. It is cheaper cost compared with the other metals and its durable, hard and easy-to-wear physical properties make it a major choice in the manufacture of equipment parts. The main problem through the uses of mild steel in industry is its resistance against corrosion, especially in acidic solutions. This case led to raise the cost of maintenance of equipment that used mild steel and as a result increased costs for the company. Organic corrosive inhibitors that also act as green chemicals, 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol have been synthesized. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution (HCl using electrochemical measurements test includes PD (Potentiodynamic, EIS (Electrochemical impedance spectroscopy, OCP (Open circuit potential and EFM (electrochemical frequency modulation. The obtained results indicate that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol acts as a good corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the impedance parameters postulated adsorption on the mild steel specimens' surfaces of, which it going to the formation of protective coating layer. It also shows that 4-hydroxybenzylideneaminomethyl-5-ethyl-1,3,4-thiadiazol corrosion inhibitors are effective in helping to reduce and slow down the corrosion process that occurs on mild steel surface in hydrochloric acid solution. Increase of corrosion inhibitor concentration provides a protective layer of mild steel. However, this protective layer becomes weak when the temperature of the solution increases. Keywords: Hydroxybenzylideneaminomethy, Potentiodynamic, Electrochemical frequency modulation, Impedance

Stress corrosion cracking of an aluminum alloy used in external fixation devices.

Science.gov (United States)

Cartner, Jacob L; Haggard, Warren O; Ong, Joo L; Bumgardner, Joel D

2008-08-01

Treatment for compound and/or comminuted fractures is frequently accomplished via external fixation. To achieve stability, the compositions of external fixators generally include aluminum alloy components due to their high strength-to-weight ratios. These alloys are particularly susceptible to corrosion in chloride environments. There have been several clinical cases of fixator failure in which corrosion was cited as a potential mechanism. The aim of this study was to evaluate the effects of physiological environments on the corrosion susceptibility of aluminum 7075-T6, since it is used in orthopedic external fixation devices. Electrochemical corrosion curves and alternate immersion stress corrosion cracking tests indicated aluminum 7075-T6 is susceptible to corrosive attack when placed in physiological environments. Pit initiated stress corrosion cracking was the primary form of alloy corrosion, and subsequent fracture, in this study. Anodization of the alloy provided a protective layer, but also caused a decrease in passivity ranges. These data suggest that once the anodization layer is disrupted, accelerated corrosion processes occur. (c) 2007 Wiley Periodicals, Inc.

Study of ion plating parameters, coating structure, and corrosion protection for aluminum coatings on uranium

International Nuclear Information System (INIS)

Egert, C.M.; Scott, D.G.

1987-01-01

A study of ion-plating parameters (primarily deposition rate and substrate bias voltage), coating structure, and the corrosion protection provided by aluminum coatings on uranium is presented. Ion plating at low temperatures yields a variety of aluminum coating structures on uranium. For example, aluminum coatings produced at high deposition rates and low substrate bias voltages are columnar with voids between columns, as expected for high-rate vapor deposition at low temperatures. On the other hand, low deposition rate and high bias voltage produce a modified coating with a dense, noncolumnar structure. These results are not in agreement with other studies that have found no relationship between deposition rate and coating structure in ion plating. This discrepancy is probably due to the high deposition rates used in these studies. An accelerated, water vapor corrosion test indicates that the columnar aluminum coatings provide some corrosion protection despite their porous nature; however, the dense noncolumnar coatings provide significantly greater protection. These results indicate that ion-plated aluminum coatings produced at low deposition rates and high substrate bias voltages creates dense coating structures that are most effective in protecting uranium from corrosion

In vitro corrosion of pure magnesium and AZ91 alloy?the influence of thin electrolyte layer thickness

OpenAIRE

Zeng, Rong-Chang; Qi, Wei-Chen; Zhang, Fen; Li, Shuo-Qi

2016-01-01

In vivo degradation predication faces a huge challenge via in vitro corrosion test due to the difficulty for mimicking the complicated microenvironment with various influencing factors. A thin electrolyte layer (TEL) cell for in vitro corrosion of pure magnesium and AZ91 alloy was presented to stimulate the in vivo corrosion in the micro-environment built by the interface of the implant and its neighboring tissue. The results demonstrated that the in vivo corrosion of pure Mg and the AZ91 all...

State of the art in protection of erosion-corrosion on vertical axis tidal current turbine

Science.gov (United States)

Musabikha, Siti; Utama, I. Ketut Aria Pria; Mukhtasor

2018-05-01

Vertical axis tidal current turbine is main part of ocean energy devices which converts the tidal current energy into electricity. Its development is arising too due to increased interest research topic concerning climate change mitigation. Due to its rotating movement, it will be induced mechanical forces, such as shear stress and/or particle impact. Because of its natural operations, vertical axis turbine is also being exposed to harsh and corroding marine environment itself. In order to secure the vertical tidal turbine devices from mechanical wear and corrosion effects which is lead to a material loss, an appropriate erosion-corrosion protection needs to be defined. Its protection actionscan be derived such as design factors, material selections, inhibitors usage, cathodic protections, and coatings. This paper aims to analyze protection method which is necessary to control erosion-corrosion phenomenon that appears to the vertical axis tidal current turbine.

Evolution of corrosion of MnCuP weathering steel submitted to wet/dry cyclic tests in a simulated coastal atmosphere

International Nuclear Information System (INIS)

Hao Long; Zhang Sixun; Dong Junhua; Ke Wei

2012-01-01

Highlights: ► The evolution of rust on MnCuP weathering steel submitted to a simulated coastal atmosphere has been investigated. ► The corrosion evolution of MnCuP weathering steel can be divided into two stages with distinct rust properties. ► A protective rust layer with higher amounts of α-FeOOH and lower Fe 3 O 4 forms as the corrosion proceeds. ► The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited. - Abstract: The evolution of rust on MnCuP weathering steel submitted to a simulated coastal atmosphere was investigated by corrosion weight gain, scanning electron microscopy, X-ray diffraction, and electrochemical methods. The results indicate that the higher corrosion rate during the first stage than that during the second stage is related closely to the rust composition and electrochemical properties. The corrosion rate evolution is caused by the formation of a protective rust layer with a higher relative amount of α-FeOOH. The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited by the protective rust layer.

Layer texture of hot-rolled BCC metals and its significance for stress-corrosion cracking of main gas pipelines

Science.gov (United States)

Perlovich, Yu. A.; Isaenkova, M. G.; Krymskaya, O. A.; Morozov, N. S.

2016-10-01

Based on data of X-ray texture analysis of hot-rolled BCC materials it was shown that the layerwise texture inhomogeneity of products is formed during their manufacturing. The effect can be explained by saturation with interstitial impurities of the surface layer, resulting in dynamical deformation aging (DDA). DDA prevents the dislocation slip under rolling and leads to an increase of lattice parameters in the external layer. The degree of arising inhomogeneity correlates with the tendency of hot-rolled sheets and obtained therefrom tubes to stress-corrosion cracking under exploitation, since internal layers have a compressive effect on external layers, and prevents opening of corrosion cracks at the tube surface.

Electrochemical corrosion behavior of composite MAO/sol-gel coatings on magnesium alloy AZ91D using combined micro-arc oxidation and sol-gel technique

International Nuclear Information System (INIS)

Shang Wei; Chen Baizhen; Shi Xichang; Chen Ya; Xiao Xiang

2009-01-01

Protective composite coatings were obtained on a magnesium alloy by micro-arc oxidation (MAO) and sol-gel technique. The coatings consisted of a MAO layer and a sol-gel layer. The microstructure and composition of the MAO coating and the composite coatings were analyzed by scanning electron microscopy (SEM) and energy dispersive X-rays (EDX). Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and total immersion tests were used to evaluate the corrosion behavior of these coatings in a 3.5 wt.% NaCl solution. The results show that the sol-gel layer provides corrosion protection by physically sealing the pores in the MAO coating and acting as a barrier. The composite coatings can suppress the corrosion process by preventing the corrosive ions from transferring or diffusing to the magnesium alloy substrate. This enhances the corrosion resistance of the magnesium alloy AZ91D significantly

Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

International Nuclear Information System (INIS)

Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming; Xue, Wenbin

2015-01-01

Highlights: • PEC/N can be applied to low melting point metal. • The spectroscopic characterization of plasma discharge is investigated. • Electron concentration and electron temperature are evaluated for PEC/N. • Phase composition of the carbonitrided layer is determined. • PEC/N improves the corrosion resistance of aluminum greatly. - Abstract: In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 10 21 m −3 and 4000 K, respectively. The carbonitrided layer contained Al 4 C 3 , AlN and Al 7 C 3 N 3 phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal

Methods for protection of high-strength welded stainless steel from corrosion cracking

International Nuclear Information System (INIS)

Lashchevskij, V.B.; Gurvich, L.Ya.; Batrakov, V.P.; Kozheurova, N.S.; Molotova, V.A.; Shvarts, M.M.

1978-01-01

The efficiency of protection from corrosion cracking under a bending stress of 100 kgf/mm 2 in a salt mist and in a sulphur dioxide atmosphere, of welded joints of steel 08Kh15N5D2T with metallizing, galvanic and varnish coatings and lubricants, and of steel 1Kh15N4AM3 with sealing compounds has been investigated. Metallization of welded joints with aluminium and zinc efficiently increases corrosion resistance in a salt mist. Galvanic coatings of Cd, Zn, and Cr increase the time to cracking in a salt mist from 2-3 to 60-80 days. The protective properties of varnishes under the effect of a salt mist decrease in the following sequence: epoxy-polyamide enamel EP-140, acrylic enamel C-38, silicone enamels KO-834, KO-811, and KO-814. In an atmosphere containing SO 2 0.15 vol.% at 100% relative humidity, the varnishes investigated, with the exception of the inhibited coating XC-596, show lower protective properties than in a salt mist. The high efficiency of protection from corrosion cracking in a salt mist of slots of steel 1Kh15N4AM3 when using organic sealing compounds U4-21 and U5-21, and also slushing lubricants and oils PVK, TsIATIM-201, K17, and AMS3 was established

Exopolysaccharides from lactic acid bacteria as corrosion inhibitors

Science.gov (United States)

Ignatova-Ivanova, Tsveteslava; Ivanov, Radoslav

2016-03-01

Bacterial EPSs (exopolysaccharides) are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus sp. are presented and discussed. Lactobacillus delbrueckii K27, Lactobacillus delbrueckii B8, Lactobacillus delbrueckii KO43, Lactobacillus delbrueckii K3, Lactobacillus delbrueckii K15 and Lactobacillus delbrueckii K17 was obtained from Collection of Department of General and Applied Microbiology, Sofia University. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% lacose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM (scanning electron microscopy) JSM 5510. It could be underlined that 10% sucrose, 10% lactose and 10% maltose in the media stimulated the process of protection of corrosion.

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.

Protecting solar collector systems from corrosion

Energy Technology Data Exchange (ETDEWEB)

1978-01-01

The main cause of the reduced life of a solar heating system is corrosion of the exterior parts and the internal components. This report outlines ways of reducing the cost of solar heating by reducing the corrosion in solar heating systems, and hence increasing the system's service life. Mechanisms for corrosion are discussed: these include galvanic corrosion and crevice corrosion. Means of minimizing corrosion at the design stage are then described. Such methods, when designing the solar collector, involve ensuring proper drainage of exterior water; eliminating situations where moisture, dirt and pollutants may collect; preventing condensation inside the collector; using proper gaskets and sealants at appropriate places; and selecting optimum materials and coatings. Interior corrosion can be minimized at the design stage by choosing a good heat transfer fluid and corrosion inhibitor, in the case of systems where liquids are used; ensuring a low enough flow rate to avoid erosion; designing the system to avoid crevices; and avoiding situations where galvanic corrosion could occur. Other procedures are given for minimizing corrosion in the construction and operation of solar heating systems. 7 figs., 7 tabs.

Real Time Corrosion Monitoring in Lead and Lead-Bismuth Systems

Energy Technology Data Exchange (ETDEWEB)

James F. Stubbins; Alan Bolind; Ziang Chen

2010-02-25

The objective of this research program is to develop a real-time, in situ corrosion monitoring technique for flowing liquid Pb and eutectic PbBi (LBE) systems in a temperature range of 400 to 650 C. These conditions are relevant to future liquid metal cooled fast reactor operating parameters. THis program was aligned with the Gen IV Reactor initiative to develp technologies to support the design and opertion of a Pb or LBE-cooled fast reactor. The ability to monitor corrosion for protection of structural components is a high priority issue for the safe and prolonged operation of advanced liquid metal fast reactor systems. In those systems, protective oxide layers are intentionally formed and maintained to limit corrosion rates during operation. This program developed a real time, in situ corrosion monitoring tecnique using impedance spectroscopy (IS) technology.

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.

An Electrochemical Investigation into the Corrosion Protection Properties of Coatings for the Active Metal Copper

OpenAIRE

Carragher, Ursula

2013-01-01

In the research presented in this thesis, corrosion protection films were synthesised and characterised. The films were based on polypyrrole (PPy) coatings doped with combinations of tartrate, oxalate and dodecylbenzene sulfonate (DBS) along with the incorporation of multiwalled carbon nanotubes (MWCNT), and viologen films adsorbed at copper. The corrosion protective properties of these films were studied and compared to the uncoated copper substrate. They were assessed and stu...

Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

Science.gov (United States)

Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

2017-11-11

Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

Corrosion Behavior of Low-C Medium-Mn Steel in Simulated Marine Immersion and Splash Zone Environment

Science.gov (United States)

Zhang, Dazheng; Gao, Xiuhua; Su, Guanqiao; Du, Linxiu; Liu, Zhenguang; Hu, Jun

2017-05-01

The corrosion behavior of low-C medium-Mn steel in simulated marine immersion and splash zone environment was studied by static immersion corrosion experiment and wet-dry cyclic corrosion experiment, respectively. Corrosion rate, corrosion products, surface morphology, cross-sectional morphology, elemental distribution, potentiodynamic polarization curves and electrochemical impedance spectra were used to elucidate the corrosion behavior of low-C medium-Mn steel. The results show that corrosion rate in immersion zone is much less than that in splash zone owing to its relatively mild environment. Manganese compounds are detected in the corrosion products and only appeared in splash zone environment, which can deteriorate the protective effect of rust layer. With the extension of exposure time, corrosion products are gradually transformed into dense and thick corrosion rust from the loose and porous one in these two environments. But in splash zone environment, alloying elements of Mn appear significant enrichment in the rust layer, which decrease the corrosion resistance of the steel.

Cerium-loaded algae exoskeletons for active corrosion protection of coated AA2024-T3

International Nuclear Information System (INIS)

Denissen, Paul J.; Garcia, Santiago J.

2017-01-01

Highlights: •Nanoporous diatom algae exoskeletons allow for local inhibitor loading. •Cerium loaded exoskeletons show diffusion controlled release from coatings. •In-situ opto-electrochemical analysis allows for accurate corrosion evaluation. •Raman spectroscopy allows for precise identification of Ce at IMs in a scribe. •High levels of protection were obtained with the Ce-diatom coatings. -- Abstract: The use of micron sized nanoporous diatom algae exoskeletons for inhibitor storage and sustained corrosion protection of coated aluminium structures upon damage is presented. In this concept the algae exoskeleton allows local inhibitor loading, limits the interaction between the cerium and the epoxy/amine coating and allows for diffusion-controlled release of the inhibitor when needed. The inhibitor release and corrosion protection by loaded exoskeletons was evaluated by UV/Vis spectrometry, a home-built optical-electrochemical setup, and Raman spectroscopy. Although this concept has been proven for a cerium-epoxy-aluminium alloy system the main underlying principle can be extrapolated to other inhibitor-coating-metal systems.

Electrochemical behavior of tube-fin assembly for an aluminum automotive condenser with improved corrosion resistance

Directory of Open Access Journals (Sweden)

M.A. Pech-Canul

Full Text Available An aluminum automotive condenser was designed to exhibit high corrosion resistance in the seawater acetic acid test (SWAAT combining zinc coated microchannel tubes and fins made with AA4343/AA3003(Zn/AA4343 brazing sheet. Electrochemical measurements in SWAAT solution were carried out under laboratory conditions using tube-fin assembly and individual fin and tube samples withdrawn from the condenser core. The aim was to gain information on the protective role of the zinc sacrificial layer and about changes in corrosion behavior as a function of immersion time. External corrosion of the tube-fin system was simulated by immersion of mini-core samples under open circuit conditions. The corrosion rate increased rapidly during the first 6 h and slowly afterwards. The short time behavior was related to the dissolution of the oxide film and fast dissolution of the outermost part of the zinc diffusion layer. With the aid of cross-sectional depth corrosion potential profiles, it was shown that as the sacrificial layer gets dissolved, the surface concentration of zinc decreases and the potential shifts to less negative values. The results of galvanic coupling of tube and fins in a mini-cell showed that the tube became the anode while the fins exhibited cathodic behavior. An evolution in the galvanic interaction was observed, due to the progressive dissolution of the sacrificial zinc layer. The difference of uncoupled potentials between tube and fins decreased from 71 mV to 32 mV after 84 h of galvanic coupling. At the end of such period there was still a part of the zinc sacrificial layer remaining which would serve for protection of the tube material for even longer periods and there were indications of slight corrosion in the fins. Keywords: Aluminum, Automotive, Corrosion, Galvanic, Zn coating

Corrosion resistance of Fe-Al alloy-coated steel under bending stress in high temperature lead-bismuth eutectic

International Nuclear Information System (INIS)

Yamaki, Eriko; Takahashi, Minoru

2009-01-01

Formation of thin Fe-Al alloy layers on the surface of cladding and structural materials is effective to protect a base material from corrosion in high temperature LBE. However, it is concerned that these protective layers may be damaged under various stress conditions. This study on Fe-Al alloy coatings deposited by unbalanced magnetron sputtering (UBMS) is focused to evaluate corrosion resistance and integrity of the Fe-Al coating layers with thickness of 0.5 mm under bending stress in high temperature LBE. High chromium steel specimens (HCM12A, Recloy10) with Fe-Al alloy coating were exposed to LBE pool with low oxygen concentration (up to 5.2x10 -8 wt%) at 550 and 650degC under 45kg-loading for 240 and 500 h. No LBE corrosion was observed in the base metal and coating layer after the tests at 550degC for 550 h. The coating layers could be barrier for corrosion resistance from LBE at 550degC, although the coating scales are cracked by the load. At 650degC, because the base metal was contoccured directly with LBE through cracks across the coating layer. Penetration of LBE to base metal and dissolution of beset metal into LBE occurred. Fe-Al coating layer was not corroded by LBE. (author)

Multiscale numerical modeling of Ce3+-inhibitor release from novel corrosion protection coatings

International Nuclear Information System (INIS)

Trenado, Carlos; Wittmar, Matthias; Veith, Michael; Strauss, Daniel J; Rosero-Navarro, Nataly C; Aparicio, Mario; Durán, Alicia; Castro, Yolanda

2011-01-01

A novel hybrid sol–gel coating has recently been introduced as an alternative to high toxic chromate-based corrosion protection systems. In this paper, we propose a multiscale computational model to estimate the amount and time scale of inhibitor release of the active corrosion protection coating. Moreover, we study the release rate under the influence of parameters such as porosity and viscosity, which have recently been implicated in the stability of the coating. Numerical simulations obtained with the model predicted experimental release tests and recent findings on the compromise between inhibitor concentration and the stability of the coating

Hot Corrosion Behavior of Stainless Steel with Al-Si/Al-Si-Cr Coating

Science.gov (United States)

Fu, Guangyan; Wu, Yongzhao; Liu, Qun; Li, Rongguang; Su, Yong

2017-03-01

The 1Cr18Ni9Ti stainless steel with Al-Si/Al-Si-Cr coatings is prepared by slurry process and vacuum diffusion, and the hot corrosion behavior of the stainless steel with/without the coatings is studied under the condition of Na2SO4 film at 950 °C in air. Results show that the corrosion kinetics of stainless steel, the stainless steel with Al-Si coating and the stainless steel with Al-Si-Cr coating follow parabolic laws in several segments. After 24 h corrosion, the sequence of the mass gain for the three alloys is the stainless steel with Al-Si-Cr coating coating coating. The corrosion products of the three alloys are layered. Thereinto, the corrosion products of stainless steel without coating are divided into two layers, where the outside layer contains a composite of Fe2O3 and FeO, and the inner layer is Cr2O3. The corrosion products of the stainless steel with Al-Si coating are also divided into two layers, of which the outside layer mainly consists of Cr2O3, and the inner layer is mainly SiO2. The corrosion film of the stainless steel with Al-Si-Cr coating is thin and dense, which combines well with substrate. Thereinto, the outside layer is mainly Cr2O3, and the inside layer is Al2O3. In the matrix of all of the three alloys, there exist small amount of sulfides. Continuous and protective films of Cr2O3, SiO2 and Al2O3 form on the surface of the stainless steel with Al-Si and Al-Si-Cr coatings, which prevent further oxidation or sulfide corrosion of matrix metals, and this is the main reason for the much smaller mass gain of the two alloys than that of the stainless steel without any coatings in the 24 h hot corrosion process.

Microstructural evaluation of the lacquered layer quality after corrosion load

Directory of Open Access Journals (Sweden)

Jaroslava Svobodova

2015-03-01

Full Text Available Surface pre-treatment is one of the most important steps before applying the final surface treatment. These pre-treatments, like phosphating, alkaline degreasing, pickling in acids, is used to remove impurities from the surface of the base material and to create appropri-ate conditions for adhesion of the final coating (metal coatings, organic coatings. Currently are on the rise surface treatments technologies, which are based on nanotechnology. It's a new generation of chemical products for the chemical surface preparation. This paper deals with the evaluation of microstructure of painted sheet metal after corrosion load with salt spray in the corrosion chamber. Metal sheets used for the experiment have been produced from low-carbon non alloy steel. For pre-treatment of the sheet metal was used alkaline degreasing (CC, iron phosphating (Feph and nanotechnology based product Alfipas (Zr in combinations: group A - CC + Zr, group B - Feph + Zr and group C - CC + Feph + Zr. The aim of this paper is to analyze the behavior of painted sheet metal after corrosion load and evaluate the effect of pretreatment to resistance of painted surface layer.

Critical Factors for the Transition from Chromate to Chromate-Free Corrosion Protection

Science.gov (United States)

2005-06-15

ascorbate, glutathione, and L-cystine that lead to DNA damage [15, 16]. One mechanistic hypothesis for Cr6+-induced DNA damage entails a Fenton -type...to damage of DNA [17]. Alternative mechanisms to the Fenton -type interaction have been proposed by Lay et al. [18], who suggest that the DNA...underlying 2024-T3 core in maintenance operations where grinding-out of cosmetic corrosion surfaces is routine. Corrosion protection of the 2024-T3

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.

Effect of Al and Ce oxide layers electrodeposited on OC4004 stainless steel on its corrosion characteristics in acid media

International Nuclear Information System (INIS)

Stoyanova, E.; Nikolova, D.; Stoychev, D.; Stefanov, P.; Marinova, T.

2006-01-01

The changes in the corrosion characteristics of stainless steel OC4004 in 0.1 M HNO 3 after electrodeposition of thin Al and Ce oxide films on it has been investigated. The Ce 2 O 3 -CeO 2 layers have been found to possess a pronounced stabilizing effect on the steel passive state and on its corrosion resistance, respectively, whereas the Al 2 O 3 layers do not improve considerably the corrosion behaviour of the SS/Al 2 O 3 system. A twice-lower corrosion current was observed with a ternary SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system in the passive region, while the zones of potentials, where the steel is in a stable passive state, are not changed. The obtained results permit the assumption that the cerium oxides layer acts as an effective cathode playing a determining role with respect to the improvement of the corrosion behavior of the steel. It has been concluded that when the SS/Al 2 O 3 /Ce 2 O 3 -CeO 2 system is used in media containing nitric acid, the corrosion will proceed at potentials where the passive state of steel would not be disturbed

Nanocontainer-based corrosion sensing coating

International Nuclear Information System (INIS)

Maia, F; Tedim, J; Bastos, A C; Ferreira, M G S; Zheludkevich, M L

2013-01-01

The present paper reports on the development of new sensing active coating on the basis of nanocontainers containing pH-indicating agent. The coating is able to detect active corrosion processes on different metallic substrates. The corrosion detection functionality based on the local colour change in active cathodic zones results from the interaction of hydroxide ions with phenolphthalein encapsulated in mesoporous nanocontainers which function as sensing nanoreactors. The mesoporous silica nanocontainers are synthesized and loaded with pH indicator phenolphthalein in a one-stage process. The resulting system is mesoporous, which together with bulkiness of the indicator molecules limits their leaching. At the same time, penetration of water molecules and ions inside the container is still possible, allowing encapsulated phenolphthalein to be sensitive to the pH in the surrounding environment and outperforming systems when an indicator is directly dispersed in the coating layer. The performed tests demonstrate the pH sensitivity of the developed nanocontainers being dispersed in aqueous solutions. The corrosion sensing functionality of the protective coatings with nanocontainers are proven for aluminium- and magnesium-based metallic substrates. As a result, the developed nanocontainers show high potential to be used in a new generation of active protective coatings with corrosion-sensing coatings. (paper)

Gel structure of the corrosion layer on cladding pipes of nuclear fuels

Czech Academy of Sciences Publication Activity Database

Medek, Jiří; Weishauptová, Zuzana

2009-01-01

Roč. 393, č. 2 (2009), s. 306-310 ISSN 0022-3115 R&D Projects: GA ČR GA106/04/0043 Institutional research plan: CEZ:AV0Z30460519 Keywords : cladding pipes of nuclear fuels * corrosion layer * zirconium alloys Subject RIV: JF - Nuclear Energetics Impact factor: 1.933, year: 2009

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 chemica...

Influence of alloying element of corrosion of Zr-Nb-Sn-Fe-Cu alloy and impedance characteristics of its oxide layer

International Nuclear Information System (INIS)

Park, S. Y.; Lee, M. H.; Choi, B. K.; Jung, Y. H.; Jung, Y. H.

2000-01-01

As a part of the advanced Zr fuel cladding development program, the autoclave corrosion test was performed on the series of Zr-0.2Nb-1.1Sn-Fe-Cu and Zr-0.4Nb-0.8Sn-Fe-Cu alloys in 70 ppm LiOH solution at 360 .deg. C. The oxide characteristics were investigated by using the Electrochemical Impedance Spectroscope(EIS) method. The corrosion resistance of the alloys was evaluated from the corrosion rate determined as a function of the concentration of main alloying elements such as Nb, Sn, Fe and Cu. The equivalent circuit was composed as a result of the spectrum from EIS measurements on the oxide layer that formed at pro- and post-transition regions. By using the capacitance characteristics of equivalent circuit, the thickness of impervious layer, it's electrical resistance and characteristics of space charge layer were evaluated. The corrosion characteristics of the Zr-Nb-Sn-Fe-Cu alloys were successfully explained by applying the EIS test results

Testing and prediction of erosion-corrosion for corrosion resistant alloys used in the oil and gas production industry

Science.gov (United States)

Rincon, Hernan E.

The corrosion behavior of CRAs has been thoroughly investigated and documented in the public literature by many researchers; however, little work has been done to investigate erosion-corrosion of such alloys. When sand particles are entrained in the flow, the degradation mechanism is different from that observed for sand-free corrosive environment. There is a need in the oil and gas industry to define safe service limits for utilization of such materials. The effects of flow conditions, sand rate, pH and temperature on the erosion-corrosion of CRAs were widely studied. An extensive experimental work was conducted using scratch tests and flow loop tests using several experimental techniques. At high erosivity conditions, a synergistic effect between erosion and corrosion was observed. Under the high sand rate conditions tested, erosivity is severe enough to damage the passive layer protecting the CRA thereby enhancing the corrosion rate. In most cases there is likely a competition between the rates of protective film removal due to mechanical erosion and protective film healing. Synergism occurs for each of the three alloys examined (13Cr and Super13Cr and 22Cr); however, the degree of synergism is quite different for the three alloys and may not be significant for 22Cr for field conditions where erosivities are typically much lower that those occurring in the small bore loop used in this research. Predictions of the corrosion component of erosion-corrosion based on scratch test data compared reasonably well to test results from flow loops for the three CRAs at high erosivity conditions. Second order behavior appears to be an appropriate and useful model for representing the repassivation process of CRAs. A framework for a procedure to predict penetration rates for erosion-corrosion conditions was developed based on the second order model behavior observed for the re-healing process of the passive film of CRAs and on computational fluid dynamics (CFD) simulations

Grain boundary defects initiation at the outer surface of dissimilar welds: corrosion mechanism studies

International Nuclear Information System (INIS)

De Bouvier, O.; Yrieix, B.

1995-11-01

Dissimilar welds located on the primary coolant system of the French PWR I plants exhibit grain boundary defects in the true austenitic zones of the first buttering layer. If grain boundaries reach the interface, they can extend to the martensitic band. Those defects are filled with compact oxides. In addition, the ferritic base metal presents some pits along the interface. Nowadays, three mechanisms are proposed to explain the initiation of those defects: stress corrosion cracking, intergranular corrosion and high temperature intergranular oxidation. This paper is dealing with the study of the mechanisms involved in the corrosion phenomenon. Intergranular corrosion tests performed on different materials show that only the first buttering layer, even with some δ ferrite, is sensitized. The results of stress corrosion cracking tests in water solutions show that intergranular cracking is possible on a bulk material representative of the first buttering layer. It is unlikely on actual dissimilar welds where the ferritic base metal protects the first austenitic layer by galvanic coupling. Therefore, the stress corrosion cracking assumption cannot explain the initiation of the defects in aqueous environment. The results of the investigations and of the corrosion studies led to the conclusion that the atmosphere could be the only possible aggressive environment. This conclusion is based on natural atmospheric exposure and accelerated corrosion tests carried out with SO 2 additions in controlled atmosphere. They both induce a severe intergranular corrosion on true sensitized austenitic materials. This corrosion studies cannot conclude definitively on the causes of the defect initiation on field, but they show that the atmospheric corrosion could produce intergranular attacks in the pure austenitic zones of the first buttering layer of the dissimilar welds and that this corrosion is stress assisted. (author). 1 ref., 6 figs., 4 tabs

Applicability of Al-powder-alloy coating to corrosion barriers of 316SS in liquid lead-bismuth eutectic

International Nuclear Information System (INIS)

Kurata, Yuji; Sato, Hidetomo; Yokota, Hitoshi; Suzuki, Tetsuya

2011-01-01

A new Al-alloy coating method using Al, Ti and Fe powders has been applied to 316SS in order to develop corrosion resistant coating in liquid lead-bismuth eutectic (LBE). The 316SS plates with coating layers of different Al concentrations were exposed to liquid LBE with controlled oxygen concentrations of 10 -6 to 10 -4 mass% at 823 K for 3600 ks. While surface oxidation and grain boundary corrosion accompanied by liquid LBE penetration are observed in 316SS without Al-alloy coating, the Al-alloy coating is effective to protect such severe corrosion attacks in liquid LBE. Although the coating layer containing 2.8 mass% Al does not always keep sufficient corrosion resistance, good corrosion resistance is obtained through the Al-oxide film formed in liquid LBE in the coating layer where the average Al concentration is 4.2 mass%. Cracks are formed in the coating layer containing 17.8 mass% Al during the coating process. The Al-powder-alloy coating applied to 316SS is promising as a corrosion resistant coating method in liquid LBE environment. (author)

Corrosion Evaluation and Corrosion Control of Steam Generators

International Nuclear Information System (INIS)

Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M.

2008-06-01

Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants

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....

Nanoscale coatings for erosion and corrosion protection of copper microchannel coolers for high powered laser diodes

Science.gov (United States)

Flannery, Matthew; Fan, Angie; Desai, Tapan G.

2014-03-01

High powered laser diodes are used in a wide variety of applications ranging from telecommunications to industrial applications. Copper microchannel coolers (MCCs) utilizing high velocity, de-ionized water coolant are used to maintain diode temperatures in the recommended range to produce stable optical power output and control output wavelength. However, aggressive erosion and corrosion attack from the coolant limits the lifetime of the cooler to only 6 months of operation. Currently, gold plating is the industry standard for corrosion and erosion protection in MCCs. However, this technique cannot perform a pin-hole free coating and furthermore cannot uniformly cover the complex geometries of current MCCs involving small diameter primary and secondary channels. Advanced Cooling Technologies, Inc., presents a corrosion and erosion resistant coating (ANCERTM) applied by a vapor phase deposition process for enhanced protection of MCCs. To optimize the coating formation and thickness, coated copper samples were tested in 0.125% NaCl solution and high purity de-ionized (DIW) flow loop. The effects of DIW flow rates and qualities on erosion and corrosion of the ANCERTM coated samples were evaluated in long-term erosion and corrosion testing. The robustness of the coating was also evaluated in thermal cycles between 30°C - 75°C. After 1000 hours flow testing and 30 thermal cycles, the ANCERTM coated copper MCCs showed a corrosion rate 100 times lower than the gold plated ones and furthermore were barely affected by flow rates or temperatures thus demonstrating superior corrosion and erosion protection and long term reliability.

Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

Energy Technology Data Exchange (ETDEWEB)

Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

2015-08-30

Highlights: • PEC/N can be applied to low melting point metal. • The spectroscopic characterization of plasma discharge is investigated. • Electron concentration and electron temperature are evaluated for PEC/N. • Phase composition of the carbonitrided layer is determined. • PEC/N improves the corrosion resistance of aluminum greatly. - Abstract: In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 10{sup 21} m{sup −3} and 4000 K, respectively. The carbonitrided layer contained Al{sub 4}C{sub 3}, AlN and Al{sub 7}C{sub 3}N{sub 3} phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal.

Corrosion and conservation of weapons and military equipment

Directory of Open Access Journals (Sweden)

Bore V. Jegdić

2012-01-01

Full Text Available This paper analyzed the conditions for the occurrence of corrosion processes on historically important weapons and military equipment made of steel during the period in outdoor environment. A considerable attention has been given to the characteristics of the most important corrosion products formed on the steel surface. The formation of akaganite, β-FeOOH is a sign of active corrosion under a layer of corrosion products. The conditions that cause the formation and regeneration of hydrochloric and sulphuric acid during the exposure to the elements were analyzed. The most often applied methods of diagnostics and procedures of removing active corrosion anions (desalination were described as well. The NaOH solution of certain pH values still has the most important application for the desalination process. The procedures for cleaning the surface before the application of protective coatings and the application of chemicals that transform rust into stable compounds were discussed. As protective coatings, different types of organic coatings plated on well-prepared steel surfaces were used and sometimes special types of waxes as well. This paper presents the results of the tests of corrosion products taken from the exhibits of weapons and military equipment from the Military Museum in Belgrade.

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.

Surface Modification of Zinc with an Oxime for Corrosion Protection in Chloride Medium

Directory of Open Access Journals (Sweden)

Ganesha Achary

2013-01-01

Full Text Available The surface treatment of zinc was done with different concentrations of an oxime (2E-2-(hydroxylamino-1,2-diphenylethanol molecule by the immersion method. The electrochemical corrosion studies of surface-treated zinc specimens were performed in aqueous sodium chloride solution (1 M, pH 5.0 at different temperatures in order to study the corrosion mechanism. The recorded electrochemical data indicated a basic modification of the cathodic corrosion behavior of the treated zinc resulting in a decrease of the electron transfer rate. The zinc samples treated by immersion in the inhibiting organic solution presented good corrosion resistance. Using scanning electron microscopy (SEM, it was found that a protective film was formed on the surface of zinc.

Exopolysaccharides from lactic acid bacteria as corrosion inhibitors

Directory of Open Access Journals (Sweden)

Ignatova-Ivanova Tsveteslava

2016-03-01

Full Text Available Bacterial EPSs (exopolysaccharides are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus sp. are presented and discussed. Lactobacillus delbrueckii K27, Lactobacillus delbrueckii B8, Lactobacillus delbrueckii KO43, Lactobacillus delbrueckii K3, Lactobacillus delbrueckii K15 and Lactobacillus delbrueckii K17 was obtained from Collection of Department of General and Applied Microbiology, Sofia University. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% lacose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM (scanning electron microscopy JSM 5510. It could be underlined that 10% sucrose, 10% lactose and 10% maltose in the media stimulated the process of protection of corrosion.

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.

Characterization and properties of shock and corrosion resistant of titanium based coatings

International Nuclear Information System (INIS)

Motoiu, P.; Rosso, M.

2001-01-01

Thermal spraying technologies are an effective way to ensure surface protection against destructive effects of wear, corrosion and oxidizing phenomena. These technologies can be applied in majority of industrial sectors in order to improve properties of new parts or for reconditioning worn out parts technology. Ideally, it would be comfortable to have a material able to resist to all type of wear, but the work condition intricacy combined with economic reason have lead to the development of a big number of powder materials that are used in thermal spraying technologies. The titanium powders are suitable for coating layers which have a good behavior in 'metal on metal friction', toughness, shock and corrosion resistance. In particular, titanium layers obtained by plasma spraying are used in different aerospace and non aerospace applications due to the combination of low density, very good mechanical properties and high corrosion resistance. The accomplishment of new titanium thermal layers is effectively used in order to increase the lifetime of different engine parts securing the thermal protection in use, resistance to high corrosion and oxidizing phenomena. This paper deals about the mechanical properties of Ti based coatings applied by plasma spray process on steel substrates, the obtained results show the possibility to apply titanium coatings where special and high performance materials are needed. (author)

Silicon protected with atomic layer deposited TiO2

DEFF Research Database (Denmark)

Seger, Brian; Tilley, David S.; Pedersen, Thomas

2013-01-01

The semiconducting materials used for photoelectrochemical (PEC) water splitting must withstand the corrosive nature of the aqueous electrolyte over long time scales in order to be a viable option for large scale solar energy conversion. Here we demonstrate that atomic layer deposited titanium di...

Effect of nanograin-boundary networks generation on corrosion of carburized martensitic stainless steel.

Science.gov (United States)

Boonruang, Chatdanai; Thong-On, Atcharawadi; Kidkhunthod, Pinit

2018-02-02

Martensitic stainless steel parts used in carbonaceous atmosphere at high temperature are subject to corrosion which results in a large amount of lost energy and high repair and maintenance costs. This work therefore proposes a model for surface development and corrosion mechanism as a solution to reduce corrosion costs. The morphology, phase, and corrosion behavior of steel are investigated using GIXRD, XANES, and EIS. The results show formation of nanograin-boundary networks in the protective layer of martensitic stainless steel. This Cr 2 O 3 -Cr 7 C 3 nanograin mixture on the FeCr 2 O 4 layer causes ion transport which is the main reason for the corrosion reaction during carburizing of the steel. The results reveal the rate determining steps in the corrosion mechanism during carburizing of steel. These steps are the diffusion of uncharged active gases in the stagnant-gas layer over the steel surface followed by the conversion of C into C 4- and O into O 2- at the gas-oxide interface simultaneously with the migration of Cr 3+ from the metal-oxide interface to the gas-oxide interface. It is proposed that previous research on Al 2 O 3 coatings may be the solution to producing effective coatings that overcome the corrosion challenges discussed in this work.

Corrosion protection of galvanized steels by silane-based treatments

Science.gov (United States)

Yuan, Wei

The possibility of using silane coupling agents as replacements for chromate treatments was investigated on galvanized steel substrates. In order to understand the influence of deposition parameters on silane film formation, pure zinc substrates were first used as a model for galvanized steel to study the interaction between silane coupling agents and zinc surfaces. The silane films formed on pure zinc substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and atomic force microscopy. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation reactions in aqueous solutions. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is almost independent of the solution dipping time. The molecular orientation of applied silane films is determined by the pH value of applied silane solutions and the isoelectric point of metal substrates. The deposition window in terms of pH value for zinc substrates is between 6.0 and 9.0. The total surface energy of the silane-coated pure zinc substrates decreases with film aging time, the decrease rate, however, is determined by the nature of silane coupling agents. Selected silane coupling agents were applied as prepaint or passivation treatments onto galvanized steel substrates. The corrosion protection provided by these silane-based treatments were evaluated by salt spray test, cyclic corrosion test, electrochemical impedance spectroscopy, and stack test. The results showed that silane coupling agents can possibly be used to replace chromates for corrosion control of galvanized steel substrates. Silane coatings provided by these silane treatments serve mainly as physical barriers. Factors that

Electrochemical behavior of tube-fin assembly for an aluminum automotive condenser with improved corrosion resistance

Science.gov (United States)

Pech-Canul, M. A.; Guía-Tello, J. C.; Pech-Canul, M. I.; Aguilar, J. C.; Gorocica-Díaz, J. A.; Arana-Guillén, R.; Puch-Bleis, J.

An aluminum automotive condenser was designed to exhibit high corrosion resistance in the seawater acetic acid test (SWAAT) combining zinc coated microchannel tubes and fins made with AA4343/AA3003(Zn)/AA4343 brazing sheet. Electrochemical measurements in SWAAT solution were carried out under laboratory conditions using tube-fin assembly and individual fin and tube samples withdrawn from the condenser core. The aim was to gain information on the protective role of the zinc sacrificial layer and about changes in corrosion behavior as a function of immersion time. External corrosion of the tube-fin system was simulated by immersion of mini-core samples under open circuit conditions. The corrosion rate increased rapidly during the first 6 h and slowly afterwards. The short time behavior was related to the dissolution of the oxide film and fast dissolution of the outermost part of the zinc diffusion layer. With the aid of cross-sectional depth corrosion potential profiles, it was shown that as the sacrificial layer gets dissolved, the surface concentration of zinc decreases and the potential shifts to less negative values. The results of galvanic coupling of tube and fins in a mini-cell showed that the tube became the anode while the fins exhibited cathodic behavior. An evolution in the galvanic interaction was observed, due to the progressive dissolution of the sacrificial zinc layer. The difference of uncoupled potentials between tube and fins decreased from 71 mV to 32 mV after 84 h of galvanic coupling. At the end of such period there was still a part of the zinc sacrificial layer remaining which would serve for protection of the tube material for even longer periods and there were indications of slight corrosion in the fins.

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.

Outdoor corrosion of zinc coated carbon steel, determined by thin layer activation

International Nuclear Information System (INIS)

Agostini, M.L.; Laguzzi, G.; De Cristofaro, N.; Stroosnijder, M.F.

2001-01-01

Thin Layer Activation was applied in the frame of a European programme addressed to the evaluation of the corrosion the behaviour of different steels. This included outdoor exposure of zinc coated carbon steel in a rural-marine climatic environment, for a period of several months. The zinc layer of specimens was 10 micrometers thick. For the TLA studies 65Zn radio nuclides were produced along the full depth of the coating, by a cyclotron accelerated deuteron beam. For quantification of the material release, activity versus depth was determined using different thickness of Zn coatings on top the carbon steel. After exposure corrosion product were removed from the surface using a pickling solution and the residual activity was determined by gamma spectrometry. The high sensitivity of the method allowed the evaluation of relatively small thickness losses (i.e. 1.2 micrometer). Thickness loss results, obtained by the TLA method, were compared with those arising from the Atomic Absorption analysis of zinc detected in the pickling solutions. A good agreement was observed between the different methods

Corrosion Evaluation and Corrosion Control of Steam Generators

Energy Technology Data Exchange (ETDEWEB)

Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

2008-06-15

Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

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.

Application of thin layer activation technique for monitoring corrosion of carbon steel in hydrocarbon processing environment.

Science.gov (United States)

Saxena, R C; Biswal, Jayashree; Pant, H J; Samantray, J S; Sharma, S C; Gupta, A K; Ray, S S

2018-05-01

Acidic crude oil transportation and processing in petroleum refining and petrochemical operations cause corrosion in the pipelines and associated components. Corrosion monitoring is invariably required to test and prove operational reliability. Thin Layer Activation (TLA) technique is a nuclear technique used for measurement of corrosion and erosion of materials. The technique involves irradiation of material with high energy ion beam from an accelerator and measurement of loss of radioactivity after the material is subjected to corrosive environment. In the present study, TLA technique has been used to monitor corrosion of carbon steel (CS) in crude oil environment at high temperature. Different CS coupons were irradiated with a 13 MeV proton beam to produce Cobalt-56 radioisotope on the surface of the coupons. The corrosion studies were carried out by subjecting the irradiated coupons to a corrosive environment, i.e, uninhibited straight run gas oil (SRGO) containing known amount of naphthenic acid (NA) at high temperature. The effects of different parameters, such as, concentration of NA, temperature and fluid velocity (rpm) on corrosion behaviour of CS were studied. Copyright © 2018 Elsevier Ltd. All rights reserved.

Corrosion and antifouling characteristics of technetium 99 in seawater

International Nuclear Information System (INIS)

Spitsyn, V.I.; Strekalov, P.V.; Balakhovskij, O.A.; Mikhajlovskij, Yu.N.

1982-01-01

The results are presented of studying the corrosive and antifouling properties of metallic technetium-99 in the Barents Sea and the Sea of Japan. Foil of 99 Tc glued on acrylic plastic served as a sample. High corrosion resistance and antifouling properties exhibited by 99 Tc in seawater point to favorable prospects of further studies aimed at development of new methods for protection against corrosion and fouling of metallic structures and parts with the use of technetium. The antifouling properties of technetium would evidently be used most efficiently when coating materials of high corrosion resistance to seawater (titanium, stainless steels, special alloys, etc.) with layers of technetium. The use of technetium for coating low-alloyed or carbon steels employed in seawater is yet problematic

Corrosion resistance of high-performance materials titanium, tantalum, zirconium

CERN Document Server

2012-01-01

Corrosion resistance is the property of a material to resist corrosion attack in a particular aggressive environment. Although titanium, tantalum and zirconium are not noble metals, they are the best choice whenever high corrosion resistance is required. The exceptionally good corrosion resistance of these high–performance metals and their alloys results from the formation of a very stable, dense, highly adherent, and self–healing protective oxide film on the metal surface. This naturally occurring oxide layer prevents chemical attack of the underlying metal surface. This behavior also means, however, that high corrosion resistance can be expected only under neutral or oxidizing conditions. Under reducing conditions, a lower resistance must be reckoned with. Only very few inorganic and organic substances are able to attack titanium, tantalum or zirconium at ambient temperature. As the extraordinary corrosion resistance is coupled with an excellent formability and weldability these materials are very valua...

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

Mechanism study of c.f.c Fe-Ni-Cr alloy corrosion in supercritical water

International Nuclear Information System (INIS)

Payet, M.

2011-01-01

Supercritical water can be use as a high pressure coolant in order to improve the thermodynamic efficiency of power plants. For nuclear concept, lifetime is an important safety parameter for materials. Thus materials selection criteria concern high temperature yield stress, creep resistance, resistance to irradiation embrittlement and also to both uniform corrosion and stress corrosion cracking.This study aims for supplying a new insight on uniform corrosion mechanism of Fe-Ni-Cr f.c.c. alloys in deaerated supercritical water at 600 C and 25 MPa. Corrosion tests were performed on 316L and 690 alloys as sample autoclaves taking into account the effect of surface finishes. Morphologies, compositions and crystallographic structure of the oxides were determined using FEG scanning electron microscopy, glow discharge spectroscopy and X-ray diffraction. If supercritical water is expected to have a gas-like behaviour in the test conditions, the results show a significant dissolution of the alloy species. Thus the corrosion in supercritical water can be considered similar to corrosion in under-critical water assuming the higher temperature and its effect on the solid state diffusion. For alloy 690, the protective oxide layer formed on polished surface consists of a chromia film topped with an iron and nickel mixed chromite or spinel. The double oxide layer formed on 316L steel seems less protective with an outer porous layer of magnetite and an inhomogeneous Cr-rich inner layer. For each alloy, the study of the inner protective scale growth mechanisms by marker or tracer experiments reveals that diffusion in the oxide scale is governed by an anionic process. However, surface finishes impact deeply the growth mechanisms. Comparisons between the results for the steel suggest that there is a competition between the oxidation of iron and chromium in supercritical water. Sufficient available chromium is required in order to form a thin oxide layer. Highly deformed or ultra fine

Hydrogen assisted cracking and CO2 corrosion behaviors of low-alloy steel with high strength used for armor layer of flexible pipe

Science.gov (United States)

Liu, Zhenguang; Gao, Xiuhua; Du, Linxiu; Li, Jianping; Zhou, Xiaowei; Wang, Xiaonan; Wang, Yuxin; Liu, Chuan; Xu, Guoxiang; Misra, R. D. K.

2018-05-01

In this study, hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) were carried out to study hydrogen assisted cracking behavior (HIC, SSCC and HE) of high strength pipeline steel used for armor layer of flexible pipe in ocean. The CO2 corrosion behavior of designed steel with high strength was studied by using immersion experiment. The experimental results demonstrate that the corrosion resistance of designed steel with tempered martensite to HIC, SSCC and HE is excellent according to specific standards, which contributes to the low concentration of dislocation and vacancies previously formed in cold rolling process. The corrosion mechanism of hydrogen induced cracking of designed steel, which involves in producing process, microstructure and cracking behavior, is proposed. The designed steel with tempered martensite shows excellent corrosion resistance to CO2 corrosion. Cr-rich compound was first formed on the coupon surface exposed to CO2-saturated brine condition and chlorine, one of the corrosion ions in solution, was rich in the inner layer of corrosion products.

Study of the properties of plasma deposited layers of nickel-chrome-aluminium-yttrium coatings resistant to oxidation and hot corrosion

Directory of Open Access Journals (Sweden)

Mihailo R. Mrdak

2012-04-01

Full Text Available The aim of this study was to examine the properties of Ni22Cr10Al1Y layers in order to obtain optimal structural - mechanical properties with the optimization of depositing parameters. Powder was deposited by the atmospheric plasma spray (APS process with the current intensity of 600, 700 and 800A, with a corresponding plasma gun power supply of 22KW, 34KW and 28KW. The evaluation of the Ni22Cr10Al1Y coating layers was made on the basis of their microhardness, tensile strength and microstructure performance. The best performance was obtained in the layers deposited with 800A and the 34KW plasma gun power supply. The coating with the best characteristics was tested to oxidation in the furnace for heat treatment without a protective atmosphere at 1100°C for one hour. The examination of the morphology of Ni22Cr10Al1Y powder particles was carried out on the SEM (Scanning Electron Microscope as well as the EDS analysis of the best layers. The microstructure of the deposited coating layers was examined with a light microscope. The microstructure analysis was performed according to the TURBOMECA standard. The mechanical properties of layers were evaluated by the method HV0.3 for microhardness and by tensile testing for bond strength. The research has shown that plasma gun power supply significantly affects the mechanical properties and microstructure of coatings that are of crucial importance for the protection of components exposed to high temperature oxidation and hot corrosion.

Characterization of wear mechanism by tribo-corrosion of nickel base alloys

International Nuclear Information System (INIS)

Ionescu, C.C.

2012-01-01

Some components of nuclear power plants, as steam generator tubes are made from Ni base alloys. These components are exposed to severe environment of high temperature and high pressure and submitted to contact mechanical stresses. These Ni - based alloys properties are determined by their ability to form on their surface an inner protective barrier film mainly composed of Cr 2 O 3 . The steam generator tubes are among the most difficult components to maintain, on the hand, because of their safety importance and secondly, the exchange tubes are subject to various degradation mechanisms, because of the harsh conditions of work. Wear by tribo-corrosion is a physicochemical aging mechanism which occurs in the management of the nuclear power plants life time. Tribo-corrosion is an irreversible process which involves mechanical and chemical / electrochemical interactions between surfaces in relative motion, in the presence of a corrosive environment. The goal of this study was to quantify in terms of quantity and quality the wear generated by tribo-corrosion process on Ni - Cr model alloys. Two model alloys: Ni -15Cr and Ni -30Cr were used to highlight, evaluate and compare the influence of the chromium content on the formation of the protective oxide layer and the role played by the latter one on the kinetics and mechanisms of wear by tribo-corrosion. The tribo-corrosion experiments were performed by using a pin-on-disc tribometer under controlled electrochemical conditions in LiOH - H 3 BO 3 solution. The corrosion - wear degradation of the protective layer during continuous and intermittent unidirectional sliding tests was investigated by a three-stage tribo-corrosion protocol. In the first stage, electrochemical techniques (open circuit potential measurements and electrochemical impedance measurements) were used without applying unidirectional sliding to monitor and evaluate the characteristics of protective oxide layer formed on the surface of the two model alloys

Corrosion protection performance of palm and mineral oil media

International Nuclear Information System (INIS)

Wan Nik Sani, W.B.; Ani, F.N.; Masjuki, H.H.

2002-01-01

In European forest, especially Scandinavian, almost all forest machines are filled with biodegradable fluid. The fluid is of synthetic type. The ratio between the lowest cost of mineral oil and the synthetic fluid is about 1:4. The high cost of this biodegradable fluid can be a major obstacle to be used in developing countries. Malaysia and South East Asia are known for its natural beauties. However, a spill of mineral based oils to their land and seas may result in long term water and soil contamination. Thus crop or agricultural based oil product can provide the solution to this problem. However, considering the demand placed on the oil in service, the service performance such as relation to component compatibility with the crop based oil is crucial to be investigated. The ability of crop based oils to protect and reduce corrosion formation is still unexplored. It is important for each oil to preserve its oxidation stability and remain non-corrosive during service. This paper reports the results of copper corrosion tests. The test includes mass change monitoring, oxide scales and microscopic analysis using Scanning Electron Microscope (SEM). Relative Increase of total acid number and weight loss during copper immersion has proved that metal corrosion in contact with oil was caused by oil degradation that produces acidic compounds. Coppers that were immersed in oil temperature of 60 0 C show that increase of temperature in presence of transition metal induces oil degradation. (Author)

Novel hybrid sol-gel coatings for corrosion protection of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Lamaka, S.V.; Montemor, M.F.; Galio, A.F.; Zheludkevich, M.L.; Trindade, C.; Dick, L.F.; Ferreira, M.G.S.

2008-01-01

This work aims to develop and study new anticorrosion films for AZ31B magnesium alloy based on the sol-gel coating approach. Hybrid organic-inorganic sols were synthesized by copolymerization of epoxy-siloxane and titanium or zirconium alkoxides. Tris(trimethylsilyl) phosphate was also used as additive to confer additional corrosion protection to magnesium-based alloy. A sol-gel coating, about 5-μm thick, shows good adhesion to the metal substrate and prevents corrosion attack in 0.005 M NaCl solution for 2 weeks. The sol-gel coating system doped with tris(trimethylsilyl)-phosphate revealed improved corrosion protection of the magnesium alloy due to formation of hydrolytically stable Mg-O-P chemical bonds. The structure and the thickness of the sol-gel film were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The corrosion behaviour of AZ31B substrates pre-treated with the sol-gel derived hybrid coatings was tested by electrochemical impedance spectroscopy (EIS). The chemical composition of the silylphosphate-containing sol-gel film at different depths was investigated by X-ray photoelectron spectroscopy (XPS) with depth profiling

Mechanism of formation of corrosion layers on nickel and nickel-based alloys in melts containing oxyanions--a review

International Nuclear Information System (INIS)

Tzvetkoff, Tzvety; Gencheva, Petia

2003-01-01

A review of the corrosion of Ni and Ni-based alloys in melts containing oxyanions (nitrate, sulphate, hydroxide and carbonate) is presented, emphasising the mechanism of growth, the composition and structure of the passivating oxide films formed on the material in such conditions. First, the thermodynamical background involving solubility and point defect chemistry calculations for oxides formed on Ni, Cr and Ni-Cr alloys in molten salt media is briefly commented. The main passivation product on the Ni surface has been reported to be cubic NiO. In the transition stage, further oxidation of the compact NiO layer has been shown to take place in which Ni(III) ions and nickel cation vacancies are formed. Transport of nickel cation vacancies has been proposed to neutralise the charges of the excess oxide ions formed in the further oxidation reaction. Ex situ analysis studies reported in the literature indicated the possible formation of Ni 2 O 3 phase in the anodic layer. During the third stage of oxidation, a survey of the published data indicated that oxygen evolution from oxyanion melts is the predominant reaction taking place on the Ni/NiO electrode. This has been supposed to lead to a further accumulation of oxygen ions in the oxide lattice presumably as oxygen interstitials, and a NiO 2 phase formation has been also suggested. Literature data on the composition of the oxide film on industrial Ni-based alloys and superalloys in melts containing oxyanions are also presented and discussed. Special attention is paid to the effect of the composition of the alloy, the molten salt mixture and the gas atmosphere on the stability and protective ability of corrosion layers

The influence of yttrium (Y) on the corrosion of Mg-Y binary alloys

International Nuclear Information System (INIS)

Liu Ming; Schmutz, Patrik; Uggowitzer, Peter J.; Song Guangling; Atrens, Andrej

2010-01-01

Research highlights: → The Y-intermetallic can accelerate corrosion and Y can increase the protectiveness of the surface layer. → In 0.1 M NaCl, the corrosion rate of Mg-Y alloys increased with increasing Y due to the Y intermetallic. → In 0.1 M NaCl, there was filiform corrosion. → In 0.1 M Na 2 SO 4 , the corrosion rate of Mg-Y alloys decreased with increasing Y in the range 3-7%Y. → Hydrogen evolution was observed from particular parts of the alloy surface. - Abstract: Corrosion of Mg-Y alloys was studied using electrochemical evaluations, immersion tests and direct observations. There were two important effects. In 0.1 M NaCl, the corrosion rate increased with increasing Y content due to increasing amounts of the Y-containing intermetallic. In 0.1 M Na 2 SO 4 , the corrosion rate decreased with increasing Y content above 3%, attributed to a more protective surface film, despite the intermetallic. The corrosion rate evaluated by electrochemical impedance spectroscopy was somewhat smaller than that evaluated from H evolution as expected from the Mg corrosion mechanism. A mechanism is proposed for filiform corrosion. Direct in situ corrosion observations revealed that a predominant feature was hydrogen evolution from particular parts of the alloy surface.

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.

Improvement of corrosion resistance of transparent conductive multilayer coating consisting of silver layers and transparent metal oxide layers

International Nuclear Information System (INIS)

Koike, Katsuhiko; Yamazaki, Fumiharu; Okamura, Tomoyuki; Fukuda, Shin

2007-01-01

An optical filter for plasma display panel (PDP) requires an electromagnetic shield with very high ability. The authors investigated a transparent conductive multilayer coating consisting of silver (Ag) layers and transparent metal oxide layers. The durability of the multilayer sputter coating, including the silver layer, is very sensitive to the surrounding atmosphere. For example, after an exposure test they found discolored points on the multilayer sputter coatings, possibly caused by migration of silver atoms in the silver layers. In their investigation, they modified the top surface of the multilayer sputter coatings with transition metals to improve the corrosion resistance of the multilayer coating. Specifically, they deposited transition metals 0.5-2 nm thick on the top surface of the multilayer coatings by sputtering. They chose indium tin oxide (ITO) as the transparent metal oxide. They applied the multilayer sputter coatings of seven layers to a polyethylene terephthalate (PET) film substrate. A cross-sectional structure of the film with the multilayer coatings is PET film/ITO/Ag/ITO/Ag/ITO/Ag/ITO. They evaluated the corrosion resistance of the films by a salt-water immersion test. In the test, they immersed the film with multilayer coatings into salt water, and then evaluated the appearance, transmittance, and electrical resistance of the multilayer coatings. They investigated several transition metals as the modifying material, and found that titanium and tantalum drastically improved the resistance of the multilayer coatings to the salt-water exposure without a significant decline in transmittance. They also investigated the relation between elapsed time after deposition of the modifying materials and resistance to the salt water. Furthermore, they investigated the effects of a heat treatment and an oxide plasma treatment on resistance to the salt water

Modeling corrosion and constituent release from a metal waste form

International Nuclear Information System (INIS)

Bauer, T. H.; Fink, J. K.; Abraham, D. P.; Johnson, I.; Johnson, S. G.; Wigeland, R. A.

2000-01-01

Several ANL ongoing experimental programs have measured metal waste form (MWF) corrosion and constituent release. Analysis of this data has initiated development of a consistent and quantitative phenomenology of uniform aqueous MWF corrosion. The effort so far has produced a preliminary fission product and actinide release model based on measured corrosion rates and calibrated by immersion test data for a 90 C J-13 and concentrated J-13 solution environment over 1-2 year exposure times. Ongoing immersion tests of irradiated and unirradiated MWF samples using more aggressive test conditions and improved tracking of actinides will serve to further validate, modify, and expand the application base of the preliminary model-including effects of other corrosion mechanisms. Sample examination using both mechanical and spectrographic techniques will better define both the nature and durability of the protective barrier layer. It is particularly important to assess whether the observations made with J-13 solution at 900 C persist under more aggressive conditions. For example, all the multiplicative factors in Table 1 implicitly assume the presence of protective barriers. Under sufficiently aggressive test conditions, such protective barriers may very well be altered or even eliminated

Oxide layers for silicon detector protection against enviroment effects

International Nuclear Information System (INIS)

Bel'tsazh, E.; Brylovska, I.; Valerian, M.

1986-01-01

It is shown that for protection of silicon detectors of nuclear radiations oxide layers could be used. The layers are produced by electrochemical oxidation of silicon surface with the following low-temperature annealing. These layers have characteristics similar to those for oxide layers produced by treatment of silicon samples at elevated temperature in oxygen flow. To determine properties of oxide layers produced by electrochemical oxidation the α-particle back-scattering method and the method of volt-farad characteristics were used. Protection properties of such layers were checked on the surface-barrier detectors. It was shown that protection properties of such detectors were conserved during long storage at room temperature and during their storage under wet-bulb temperature. Detectors without protection layer have worsened their characteristics

Development and application of corrosion and protection database using intranet; Intoranetto wo riyo shita zairyo fushoku detabesu no kochiku to katsuyo

Energy Technology Data Exchange (ETDEWEB)

Futatsugi, Takashi.; Baba, Fumio.; Suzuki, Tsuguo. [Ajinomoto Co., Inc., Tokyo (Japan). Technology and Engineering Laboratories

1999-05-15

A new corrosion and protection database system, which stores a large amount of documents and informations about corrosion and protection, such as case histories, materials data, fabrication methods and repairing methods, has been developed. Users of the database system can be accessed using WWW browser via Intranet. This database can be operated by easy handling with only click and drug. The database system is expected to offer a wide knowledge for corrosion related engineers and to decrease corrosion troubles. (author)

Corrosion Properties of Dissimilar Friction Stir Welded 6061 Aluminum and HT590 Steel

Science.gov (United States)

Seo, Bosung; Song, Kuk Hyun; Park, Kwangsuk

2018-05-01

Corrosion properties of dissimilar friction stir welded 6061 aluminum and HT590 steel were investigated to understand effects of galvanic corrosion. As cathode when coupled, HT590 was cathodically protected. However, the passivation of AA6061 made the aluminum alloy cathode temporarily, which leaded to corrosion of HT590. From the EIS analysis showing Warburg diffusion plot in Nyquist plots, it can be inferred that the stable passivation layer was formed on AA6061. However, the weld as well as HT590 did not show Warburg diffusion plot in Nyquist plots, suggesting that there was no barrier for corrosion or even if it exists, the barrier had no function for preventing and/or retarding charge transport through the passivation layer. The open circuit potential measurements showed that the potential of the weld was similar to that of HT590, which lied in the pitting region for AA6061, making the aluminum alloy part of the weld keep corrosion state. That resulted in the cracked oxide film on AA6061 of the weld, which could not play a role of corrosion barrier.

A stable organic-inorganic hybrid layer protected lithium metal anode for long-cycle lithium-oxygen batteries

Science.gov (United States)

Zhu, Jinhui; Yang, Jun; Zhou, Jingjing; Zhang, Tao; Li, Lei; Wang, Jiulin; Nuli, Yanna

2017-10-01

A stable organic-inorganic hybrid layer (OIHL) is direct fabricated on lithium metal surface by the interfacial reaction of lithium metal foil with 1-chlorodecane and oxygen/carbon dioxide mixed gas. This favorable OIHL is approximately 30 μm thick and consists of lithium alkyl carbonate and lithium chloride. The lithium-oxygen batteries with OIHL protected lithium metal anode exhibit longer cycle life (340 cycles) than those with bare lithium metal anode (50 cycles). This desirable performance can be ascribed to the robust OIHL which prevents the growth of lithium dendrites and the corrosion of lithium metal.

Effect of Al Hot-Dipping on High-Temperature Corrosion of Carbon Steel in N2/0.1% H2S Gas

Directory of Open Access Journals (Sweden)

Muhammad Ali Abro

2016-02-01

Full Text Available High-temperature corrosion of carbon steel in N2/0.1% H2S mixed gas at 600–800 °C for 50–100 h was studied after hot-dipping in the aluminum molten bath. Hot-dipping resulted in the formation of the Al topcoat and the Al-Fe alloy layer firmly adhered on the substrate. The Al-Fe alloy layer consisted primarily of a wide, tongue-like Al5Fe2 layer and narrow Al3Fe layer. When corroded at 800 °C for 100 h, the Al topcoat partially oxidized to the protective but non-adherent α-Al2O3 layer, and the interdiffusion converted the Al-Fe alloy layer to an (Al13Fe4, AlFe3-mixed layer. The interdiffusion also lowered the microhardness of the hot-dipped steel. The α-Al2O3 layer formed on the hot-dipped steel protected the carbon steel against corrosion. Without the Al hot-dipping, the carbon steel failed by forming a thick, fragile, and non-protective FeS scale.

Effects of surface modification with hydroxyl terminated polydimethylsiloxane on the corrosion protection of polyurethane coating

International Nuclear Information System (INIS)

Jeon, Jae Hong; Shon, Min Young

2014-01-01

Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ⅠZⅠ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior

Corrosion Resistance of a Cast-Iron Material Coated With a Ceramic Layer Using Thermal Spray Method

Science.gov (United States)

Florea, C. D.; Bejinariu, C.; Munteanu, C.; Istrate, B.; Toma, S. L.; Alexandru, A.; Cimpoesu, R.

2018-06-01

Cast-iron 250 used for breake systems present many corrosion signs after a mean usage time based on the environment conditions they work. In order to improve them corrosion resistance we propose to cover the active part of the material using a ceramic material. The deposition process is an industrial deposition system based on thermal spraying that can cover high surfaces in low time. In this articol we analyze the influence of a ceramic layer (40-50 µm) on the corrosion resistance of FC250 cast iron. The results were analyzed using scanning electron microscopy (SEM), X-ray energy dispersive (EDS) and linear and cyclic potentiometry.

Corrosion resistance of Zn-Al layered double hydroxide/poly(lactic acid) composite coating on magnesium alloy AZ31

Science.gov (United States)

Zeng, Rong-Chang; Li, Xiao-Ting; Liu, Zhen-Guo; Zhang, Fen; Li, Shuo-Qi; Cui, Hong-Zhi

2015-12-01

A Zn-Al layered double hydroxide (ZnAl-LDH) coating consisted of uniform hexagonal nano-plates was firstly synthesized by co-precipitation and hydrothermal treatment on the AZ31 alloy, and then a poly(lactic acid) (PLA) coating was sealed on the top layer of the ZnAl-LDH coating using vacuum freeze-drying. The characteristics of the ZnAl-LDH/PLA composite coatings were investigated by means of XRD, SEM, FTIR and EDS. The corrosion resistance of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the ZnAl-LDH coating contained a compact inner layer and a porous outer layer, and the PLA coating with a strong adhesion to the porous outer layer can prolong the service life of the ZnAl-LDH coating. The excellent corrosion resistance of this composite coating can be attributable to its barrier function, ion-exchange and self-healing ability.

Surface films and corrosion of copper

International Nuclear Information System (INIS)

Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M.

1999-03-01

In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

Corrosion and anticorrosion. Industrial practice

International Nuclear Information System (INIS)

Beranger, G.; Mazille, H.

2002-01-01

This book comprises 14 chapters written with the collaboration of about 50 French experts of corrosion. It is complementary to another volume entitled 'corrosion of metals and alloys' and published by the same editor. This volume comprises two parts: part 1 presents the basic notions of corrosion phenomena, the properties of surfaces, the electrochemical properties of corrosion etc.. Part 2 describes the most frequent forms of corrosion encountered in industrial environments and corresponding to specific problems of protection: marine environment, atmospheric corrosion, galvanic corrosion, tribo-corrosion, stress corrosion etc.. The first 8 chapters (part 1) treat of the corrosion problems encountered in different industries and processes: oil and gas production, chemical industry, phosphoric acid industry, PWR-type power plants, corrosion of automobile vehicles, civil engineering and buildings, corrosion of biomaterials, non-destructive testing for the monitoring of corrosion. The other chapters (part 2) deal with anticorrosion and protective coatings and means: choice of materials, coatings and surface treatments, thick organic coatings and enamels, paints, corrosion inhibitors and cathodic protection. (J.S.)

Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

Science.gov (United States)

Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja; Jellesen, Morten Stendahl; Ambat, Rajan

2017-11-01

Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively. Moreover, the use of sodium silicate resulted in the formation of distinct microstructure and incorporation of silicate into the oxide film. These oxide films reduced the anodic activity 4 times, while the corrosion protection by silicate containing oxide was the function of its concentration. Further, in acid salt spray and filiform corrosion tests, oxide layer containing silicate exhibited two times higher corrosion resistance.

In vitro corrosion of pure magnesium and AZ91 alloy—the influence of thin electrolyte layer thickness

Science.gov (United States)

Zeng, Rong-Chang; Qi, Wei-Chen; Zhang, Fen; Li, Shuo-Qi

2016-01-01

In vivo degradation predication faces a huge challenge via in vitro corrosion test due to the difficulty for mimicking the complicated microenvironment with various influencing factors. A thin electrolyte layer (TEL) cell for in vitro corrosion of pure magnesium and AZ91 alloy was presented to stimulate the in vivo corrosion in the micro-environment built by the interface of the implant and its neighboring tissue. The results demonstrated that the in vivo corrosion of pure Mg and the AZ91 alloy was suppressed under TEL condition. The AZ91 alloy was more sensitive than pure Mg to the inhibition of corrosion under a TEL thickness of less than 200 µm. The TEL thickness limited the distribution of current, and thus localized corrosion was more preferred to occur under TEL condition than in bulk solution. The TEL cell might be an appropriate approach to simulating the in vivo degradation of magnesium and its alloys. PMID:26816655

Corrosion protection of metals by phosphate coatings and ecologically beneficial alternatives. Properties and mechanisms

International Nuclear Information System (INIS)

Weng Duan.

1995-01-01

The corrosion and protection characteristics of inorganic zinc and manganese phosphate coatings in aqueous solution have been examined by physical methods, accelerated corrosion tests and electrochemical polarization and impedance measurements. Some water-soluble organic films have been evaluated for the temporary protection of metal parts as the ecologically beneficial alternatives to phosphate coatings. The results show that zinc phosphate is a better insulator than manganese phosphate, but the porosity of the former is inferior to that of the latter. In neutral and alkaline solutions the anodic current of both zinc and manganese phosphates decreases and their open potential moves in a positive direction. In acidic medium both the polarization current and the open potential are close to those of the substrate. Confirmed by the impedance measurements, the corrosion of phosphated steel in acidic solution is controlled by a dissolution reaction, in neutral medium is first reaction controlled then diffusion controlled, and in alkaline environment only diffusion controlled. The insulation of acrylate+copolymer, epoxy and inhibitor+bonding materials is superior to that of zinc or manganese phosphates. In general, most of the alternatives can afford a better temporary protection for metal parts compared to inorganic phosphate coatings. The corrosion failure of inorganic phosphate coatings is mainly induced by the electrochemical dissolution of the substrate. This electrochemical process initiates at the bottom of the pores within the coating. In neutral solution, the hydrolysis of corrosion products decrease the pH value of the solution in the anodic zone, resulting in an acidic dissolution of phosphate coatings. At the same time, the depolarization of oxygen increases the pH value in the cathodic zone, causing an alkaline hydrolysis of phosphates. (author) figs., tabs., 149 refs

Examples illustrating the effects of high-temperature corrosion and protective coatings on the creep-to-rupture behaviour of materials resistant to very high temperatures

International Nuclear Information System (INIS)

Sachova, E.; Hougardy, H.P.; Granacher, J.

1989-01-01

Assessing the creep stress, it is assumed in general that the sub-surface effects in a specimen correspond to those at the surface. Particularly in very high temperature environments, however, oxidation is an additional effect to be taken into account, and there are other operational stresses to be reckoned with, as e.g. hot gas corrosion of gas turbine blades. The reduction of the effective cross section due to corrosion for instance of the material affected by long-term creep leads to an increase in stresses and thus shortens the period up to rupture. Protective coatings will prevent or at least delay corrosion. The paper reports the performance of various protective coatings. Pt-Al coatings have have been found to remain intact even on specimens with the longest testing periods up to rupture, to an extent that there was no oxidation at the grain boundaries proceeding from the surface to the sub-surface material. The same applies to the plasma-sprayed coatings, although in some cases pores had developed in the coating. The chromium alitizations were used up irregularly over the surface of some specimens tested at 1000deg C. Chromizing layers have been found to be more strongly damaged than the other coatings tested under comparable conditions. (orig./RHM) [de

Corrosion behavior of carbon steel in wet Na-bentonite medium

International Nuclear Information System (INIS)

Yeon, Jae-Won; Ha, Young-Kyoung; Choi, In-Kyu; Chun, Kwan-Sik

1996-01-01

Corrosion behaviors of carbon steel in wet Na-bentonite medium were studied. Corrosion rate of carbon steel in wet bentonite was measured to be 20 μm/yr at 25 deg C using the AC impedance technique. This value is agreed with that obtained by weight loss at 40 deg C for 1 year. The effect of bicarbonate ion on the corrosion of carbon steel in wet bentonite was also evaluated. The carbon steels in wet bentonite having 0.001, 0.01, and 0.1 M concentration of bicarbonate ion gave corrosion rates of 20, 8, and 0.2 μm/yr, respectively. Corrosion potentials of specimens were also measured and compared with the AC impedance results. Both results indicated that bicarbonate ion could effectively reduce the corrosion rate of carbon steels in bentonite due to the formation of protective layer on the carbon steel. (author)

Chemical passivation as a method of improving the electrochemical corrosion resistance of Co-Cr-based dental alloy.

Science.gov (United States)

Rylska, Dorota; Sokołowski, Grzegorz; Sokołowski, Jerzy; Łukomska-Szymańska, Monika

2017-01-01

The purpose of the study was to evaluate corrosion resistance of Wirobond C® alloy after chemical passivation treatment. The alloy surface undergone chemical passivation treatment in four different media. Corrosion studies were carried out by means of electrochemical methods in saline solution. Corrosion effects were determined using SEM. The greatest increase in the alloy polarization resistance was observed for passive layer produced in Na2SO4 solution with graphite. The same layer caused the highest increase in corrosion current. Generally speaking, the alloy passivation in Na2SO4 solution with graphite caused a substantial improvement of the corrosion resistance. The sample after passivation in Na2SO4 solution without graphite, contrary to others, lost its protective properties along with successive anodic polarization cycles. The alloy passivation in Na3PO4 solution with graphite was the only one that caused a decrease in the alloy corrosion properties. The SEM studies of all samples after chemical passivation revealed no pit corrosion - in contrast to the sample without any modification. Every successive polarization cycle in anodic direction of pure Wirobond C® alloy enhances corrosion resistance shifting corrosion potential in the positive direction and decreasing corrosion current value. The chemical passivation in solutions with low pH values decreases susceptibility to electrochemical corrosion of Co-Cr dental alloy. The best protection against corrosion was obtained after chemical passivation of Wirobond C® in Na2SO4 solution with graphite. Passivation with Na2SO4 in solution of high pH does not cause an increase in corrosion resistance of WIROBOND C. Passivation process increases alloy resistance to pit corrosion.

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.

Constructing superhydrophobic WO3@TiO2 nanoflake surface beyond amorphous alloy against electrochemical corrosion on iron steel

Science.gov (United States)

Yu, S. Q.; Ling, Y. H.; Wang, R. G.; Zhang, J.; Qin, F.; Zhang, Z. J.

2018-04-01

To eliminate harmful localized corrosion, a new approach by constructing superhydrophobic WO3@TiO2 hierarchical nanoflake surface beyond FeW amorphous alloy formed on stainless steel was proposed. Facile dealloying and liquid deposition was employed at low temperature to form a nanostructured layer composing inner WO3 nanoflakes coated with TiO2 nanoparticles (NPs) layer. After further deposition of PFDS on nanoflakes, the contact angle reached 162° while the corrosion potential showed a negative shift of 230 mV under illumination, resulting in high corrosion resistance in 3.5 wt% NaCl solution. The tradeoff between superhydrophobic surface and photo-electro response was investigated. It was found that this surface feature makes 316 SS be immune to localized corrosion and a pronounced photo-induced process of electron storage/release as well as the stability of the functional layer were detected with or without illumination, and the mechanism behind this may be related to the increase of surface potential due to water repellence and the delayed cathodic protection of semiconducting coating derived mainly from the valence state changes of WO3. This study demonstrates a simple and low-cost electrochemical approach for protection of steel and novel means to produce superhydrophobic surface and cathodic protection with controllable electron storage/release on engineering scale.

EUROCORR 2007 - The European corrosion congress - Progress by corrosion control. Book of Abstracts

International Nuclear Information System (INIS)

2007-01-01

This book of abstracts contains lectures, workshops and posters which were held on the European Corrosion Congress 2007 in Freiburg (Germany). The main topics of the sessions and posters are: 1. Corrosion and scale inhibition; 2. Corrosion by hot gases and combustion products; 3. Nuclear corrosion; 4. Environment sensitive fracture; 5. Surface Science; 6. Physico-chemical methods of corrosion testing; 7. Marine corrosion; 8. Microbial corrosion; 9. Corrosion of steel in concrete; 10. Corrosion in oil and gas production; 11. Coatings; 12. Corrosion in the refinery industry; 13. Cathodic protection; 14. Automotive Corrosion; 15. Corrosion of polymer materials. The main topics of the workshops are: 1. High temperature corrosion in the chemical, refinery and petrochemical industries; 2. Bio-Tribocorrosion; 3. Stress corrosion cracking in nuclear power plants; 4. Corrosion monitoring in nuclear systems; 5. Cathodic protection for marine and offshore environments; 6. Self-healing properties of new surface treatments; 7. Bio-Tribocorrosion - Cost 533/Eureka-ENIWEP-Meeting; 8. Drinking water systems; 9. Heat exchangers for seawater cooling

Criteria for Corrosion Protection of Aluminum-Clad Spent Nuclear Fuel in Interim Wet Storage

International Nuclear Information System (INIS)

Howell, J.P.

1999-01-01

Storage of aluminum-clad spent nuclear fuel at the Savannah River Site (SRS) and other locations in the U. S. and around the world has been a concern over the past decade because of the long time interim storage requirements in water. Pitting corrosion of production aluminum-clad fuel in the early 1990''s at SRS was attributed to less than optimum quality water and corrective action taken has resulted in no new pitting since 1994. The knowledge gained from the corrosion surveillance testing and other investigations at SRS over the past 8 years has provided an insight into factors affecting the corrosion of aluminum in relatively high purity water. This paper reviews some of the early corrosion issues related to aluminum-clad spent fuel at SRS, including fundamentals for corrosion of aluminum alloys. It updates and summarizes the corrosion surveillance activities supporting the future storage of over 15,000 research reactor fuel assemblies from countries over the world during the next 15-20 years. Criteria are presented for providing corrosion protection for aluminum-clad spent fuel in interim storage during the next few decades while plans are developed for a more permanent disposition

Contribution to the study of the influence of zinc bath composition on corrosion resistance of coatings obtained by galvanization

International Nuclear Information System (INIS)

Cabrillac, Claude

1969-01-01

This research thesis deals with the influence of zinc purity on the corrosion resistance of a coating obtained by galvanization, and on its effect on cathodic protection. This study therefore addresses methods and tests processes (notably salt spray test) aiming at assessing the efficiency of steel protection by hot galvanization, and aims at highlighting the influence of galvanization bath purity or composition on corrosion resistance of galvanized layers

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.

Microstructures and properties of low-chromium high corrosion-resistant TiC-VC reinforced Fe-based laser cladding layer

International Nuclear Information System (INIS)

Zhang, Hui; Zou, Yong; Zou, Zengda; Wu, Dongting

2015-01-01

Highlights: • The cladding layer with 3.0%Cr and 0.25%CeO 2 showed a good corrosion resistance. • Passive film formed on the cladding layer without Cr and CeO 2 was Fe 3 O 4 . • Fe 3 O 4 displayed p type semiconductivity. • Passive film formed on the cladding layer with Cr and CeO 2 was Fe(OH) 3 and Cr(OH) 3 . • Fe(OH) 3 displayed n type while Cr(OH) 3 displayed p type semiconductivity. - Abstract: Effects of 3.0 wt.%Cr and/or 0.25 wt.%CeO 2 on microstructures and properties of TiC-VC reinforced Fe-based cladding layer were investigated by using X-ray diffractometry (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). Passive films formed on cladding layers surface were investigated by using X-ray photoelectron spectroscopy (XPS) and Mott-Schottky analysis. Results showed that phases of cladding layers were α-Fe, γ-Fe, TiC, VC and TiVC 2 . There were no obvious effects of adding 3.0 wt.%Cr and/or 0.25 wt.%CeO 2 on cladding layers phases. The microstructure of the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO 2 was lath martensite and retained austenite. Microhardness of the cladding layer with 0.25 wt.%CeO 2 decreased slightly. Microhardness and corrosion resistance of the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO 2 both increased, the corrosion resistance increased 7.33 times while the EIS Nyquist spectrum transformed into a capacitive arc. The passive film formed on the cladding layer without Cr and CeO 2 was Fe 3 O 4 which displayed p type semiconductivity. The passive film formed on the cladding layer with 3.0 wt.%Cr and 0.25 wt.%CeO 2 was composed of Fe(OH) 3 and Cr(OH) 3 , which displayed n and p type semiconductivity respectively

Characterizing the structural degradation in a PEMFC cathode catalyst layer : carbon corrosion

Energy Technology Data Exchange (ETDEWEB)

Young, A.; Stumper, J. [Ballard Power Systems, Burnaby, BC (Canada); Gyenge, E. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering

2009-07-01

The structural degradation resulting from carbon corrosion of a cathode catalyst layer in a polymer electrolyte membrane fuel cell (PEMFC) was investigated in this study. In order to oxidize the catalyst carbon support, the PEMFC catalyst layer was subjected to a 30 hour accelerated stress test that cycled the cathode potential from 0.1 to 1.5 VRHE at 30 and 150 second intervals. The rate and amount of carbon loss was determined by measuring the carbon dioxide in the exhaust gas. The structural degradation of the catalyst layer was characterized and correlated to the PEMFC performance using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and polarization analyses. This analysis revealed a clear thinning of the cathode catalyst layer and gas diffusion layer carbon sub-layer, and a reduction in the effective platinum surface area due to the carbon support oxidation. The thinned cathode catalyst layer changed the water management, and increased the voltage loss associated with the oxygen mass transport and catalyst layer ohmic resistance. In order to further develop and verify this methodology for other degradation mechanisms, emphasis was placed on EIS measurements.

Corrosion of thin, magnetron sputtered Nb_2O_5 films

International Nuclear Information System (INIS)

Pillis, Marina Fuser; Geribola, Guilherme Altomari; Scheidt, Guilherme; Gonçalves de Araújo, Edval; Lopes de Oliveira, Mara Cristina; Antunes, Renato Altobelli

2016-01-01

Highlights: • Niobium oxide based films were obtained by DC magnetron sputtering. • Different deposition times were tested. • The best corrosion resistance was obtained for the Nb_2O_5 film produced at 15′. • Film porosity determines the corrosion resistance. - Abstract: Niobium oxide based thin films were deposited on AISI 316 stainless steel substrates using reactive DC magnetron sputtering. Structure, composition and corrosion resistance of the niobium oxide films were studied. The corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The concentration of niobium and oxygen in the films was obtained by Rutherford backscattering spectroscopy (RBS). The film structure was analyzed by X-ray diffractometry. The corrosion resistance of the substrate was improved by the Nb_2O_5 layers. The best protective performance was achieved for the deposition time of 15 min.

Numerical model of RC beam response to corrosion

Science.gov (United States)

German, Magdalena; Pamin, Jerzy

2018-01-01

The chloride-induced corrosion of reinforcement used to be represented by Tuutti's model with initiation and propagation phases. During the initiation phase chlorides penetrate the concrete cover and accumulate around reinforcement bars. The chloride concentration in concrete increases until it reaches a chloride threshold value, causing deterioration of the passive layer of reinforcement. Then the propagation phase begins. During the propagation phase steel has no natural anti-corrosion protection, a corrosion current flows and this induces the production of rust. A growing volume of corrosion products generates stresses in concrete, which leads to cracking, splitting, delamination and loss of strength. The mechanical response of RC elements to reinforcement corrosion has mostly been examined on the basis of a 2D cross-section analysis. However, with this approach it is not possible to represent both corrosion and static loading. In the paper a 3D finite element model of an RC beam with the two actions applied is presented. Rust is represented as an interface between steel and concrete, considering the volumetric expansion of rust.

An assessment of thermal spray coating technologies for high temperature corrosion protection

International Nuclear Information System (INIS)

Heath, G.R.; Heimgartner, P.; Gustafsson, S.; Irons, G.; Miller, R.

1997-01-01

The use of thermally sprayed coatings in combating high temperature corrosion continues to grow in the major industries of chemical, waste incineration, power generation and pulp and paper. This has been driven partially by the development of corrosion resistant alloys, improved knowledge and quality in the thermal spray industry and continued innovation in thermal spray equipment. There exists today an extensive range of thermal spray process options, often with the same alloy solution. In demanding corrosion applications it is not sufficient to just specify alloy and coating method. For the production of reliable coatings the whole coating production envelope needs to be considered, including alloy selection, spray parameters, surface preparation, base metal properties, heat input etc. Combustion, arc-wire, plasma, HVOF and spray+fuse techniques are reviewed and compared in terms of their strengths and limitations to provide cost-effective solutions for high temperature corrosion protection. Arc wire spraying, HP/HVOF and spray+fuse are emerging as the most promising techniques to optimise both coating properties and economic/practical aspects. (orig.)

49 CFR 195.581 - Which pipelines must I protect against atmospheric corrosion and what coating material may I use?

Science.gov (United States)

2010-10-01

... corrosion and what coating material may I use? 195.581 Section 195.581 Transportation Other Regulations... Corrosion Control § 195.581 Which pipelines must I protect against atmospheric corrosion and what coating... atmosphere, except pipelines under paragraph (c) of this section. (b) Coating material must be suitable for...

Molybdate/phosphate composite conversion coating on magnesium alloy surface for corrosion protection

International Nuclear Information System (INIS)

Yong Zhiyi; Zhu Jin; Qiu Cheng; Liu Yali

2008-01-01

In this paper, a new conversion coating-molybdate/phosphate (Mo/P) coating on magnesium alloy was prepared and investigated by electrochemical impedance spectra (EIS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and salt-water immersion experiments, respectively. The results demonstrated that the Mo/P coating contained composite phases, which were consisted of metaphosphate as well as molybdate oxide with an 'alveolate-crystallized' structure. The composite Mo/P conversion coating had better corrosion resistance performance than molybdate (Mo) coating, and even had almost comparable corrosion protection for Mg alloy to the traditional chromate-based coating.

Modelling aqueous corrosion of nuclear waste phosphate glass

Energy Technology Data Exchange (ETDEWEB)

Poluektov, Pavel P.; Schmidt, Olga V.; Kascheev, Vladimir A. [Bochvar All-Russian Scientific Research Institute for Inorganic Materials (VNIINM), Moscow (Russian Federation); Ojovan, Michael I., E-mail: m.ojovan@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2017-02-15

A model is presented on nuclear sodium alumina phosphate (NAP) glass aqueous corrosion accounting for dissolution of radioactive glass and formation of corrosion products surface layer on the glass contacting ground water of a disposal environment. Modelling is used to process available experimental data demonstrating the generic inhibiting role of corrosion products on the NAP glass surface. - Highlights: • The radionuclides yield is determined by the transport from the glass through the surface corrosion layer. • Formation of the surface layer is due to the dissolution of the glass network and the formation of insoluble compounds. • The model proposed accounts for glass dissolution, formation of corrosion layer, specie diffusion and chemical reactions. • Analytical solutions are found for corrosion layer growth rate and glass components component leaching rates.

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)

Development of corrosion resistant materials for an electrolytic reduction process of a spent nuclear fuel

International Nuclear Information System (INIS)

Jong-Hyeon Lee; Soo-Haeng Cho; Jeong-Gook Oh; Eung-Ho Kim

2008-01-01

New alloys were designed and prepared to improve their corrosion resistance in an electrolytic reduction environment for a spent oxide fuel on the basis of a thermodynamical assessment. A considerable solubility of Si was confirmed in the Ni alloys and their corrosion resistance was drastically increased with the addition of Si. It was confirmed that a protective oxide layer was formed during a corrosion test due to a reaction among the alloying elements such as Cr, Al and Si. (authors)

Atomic layer deposited ZrO2 nanofilm on Mg-Sr alloy for enhanced corrosion resistance and biocompatibility.

Science.gov (United States)

Yang, Qiuyue; Yuan, Wei; Liu, Xiangmei; Zheng, Yufeng; Cui, Zhenduo; Yang, Xianjin; Pan, Haobo; Wu, Shuilin

2017-08-01

The biodegradability and good mechanical property of magnesium alloys make them potential biomedical materials. However, their rapid corrosion rate in the human body's environment impairs these advantages and limits their clinical use. In this work, a compact zirconia (ZrO 2 ) nanofilm was fabricated on the surface of a magnesium-strontium (Mg-Sr) alloy by the atomic layer deposition (ALD) method, which can regulate the thickness of the film precisely and thus also control the corrosion rate. Corrosion tests reveal that the ZrO 2 film can effectively reduce the corrosion rate of Mg-Sr alloys that is closely related to the thickness of the film. The cell culture test shows that this kind of ZrO 2 film can also enhance the activity and adhesion of osteoblasts on the surfaces of Mg-Sr alloys. The significance of the current work is to develop a zirconia nanofilm on biomedical MgSr alloy with controllable thickness precisely through atomic layer deposition technique. By adjusting the thickness of nanofilm, the corrosion rate of Mg-Sr alloy can be modulated, thereafter, the degradation rate of Mg-based alloys can be controlled precisely according to actual clinical requirement. In addition, this zirconia nanofilm modified Mg-Sr alloys show excellent biocompatibility than the bare samples. Hence, this work provides a new surface strategy to control the degradation rate while improving the biocompatibility of substrates. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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)

Silica doped with lanthanum sol–gel thin films for corrosion protection

International Nuclear Information System (INIS)

Abuín, M.; Serrano, A.; Llopis, J.; García, M.A.; Carmona, N.

2012-01-01

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: ► Silica sol–gel films doped with lanthanum ions were synthesized. ► Films from lanthanum-acetate and La-alkoxide were prepared for comparison purposes. ► La-acetate is an affordable chemical reactive preferred for the industry. ► Films properties were explored by scanning electron microscopy and X-Ray absorption spectroscopy. ► An alternative to anticorrosive pre-treatments for metallic surfaces is suggested.

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.

Slippery liquid-infused porous surfaces fabricated on aluminum as a barrier to corrosion induced by sulfate reducing bacteria

International Nuclear Information System (INIS)

Wang, Peng; Lu, Zhou; Zhang, Dun

2015-01-01

Highlights: • Slippery liquid-infused porous surfaces (SLIPS) were fabricated over aluminum. • SLIPS depress the adherence of sulfate reducing bacteria in static seawater. • SLIPS inhibit the microbiological corrosion of aluminum in static seawater. • The possible microbiological corrosion protection mechanism of SLIPS is proposed. - Abstract: Microbiological corrosion induced by sulfate reducing bacteria (SRB) is one of the main threatens to the safety of marine structure. To reduce microbiological corrosion, slippery liquid infused porous surfaces (SLIPS) were designed and fabricated on aluminum substrate by constructing rough aluminum oxide layer, followed by fluorination of the rough layer and infiltration with lubricant. The as-fabricated SLIPS were characterized with wettability measurement, SEM and XPS. Their resistances to microbiological corrosion induced by SRB were evaluated with fluorescence microscopy and electrochemical measurement. It was demonstrated that they present high resistance to bacteria adherence and the resultant microbiological corrosion in static seawater

Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

DEFF Research Database (Denmark)

Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja

2017-01-01

. Moreover, the use of sodium silicate resulted in the formation of distinct microstructure and incorporation of silicate into the oxide film. These oxide films reduced the anodic activity 4 times, while the corrosion protection by silicate containing oxide was the function of its concentration. Further......Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively......, in acid salt spray and filiform corrosion tests, oxide layer containing silicate exhibited two times higher corrosion resistance....

Corrosion and protection of spent Al-clad research reactor fuel during extended wet storage

International Nuclear Information System (INIS)

Ramanathan, Lalgudi V.

2009-01-01

A variety of spent research reactor fuel elements with different fuel meats, geometries and 235 U enrichments are presently stored under water in basins throughout the world. More than 90% of these fuels are clad in aluminum (Al) or its alloy and are susceptible to corrosion. This paper presents an overview of the influence of Al alloy composition, galvanic effects (Al alloy/stainless steel), crevice effects, water parameters and synergism between these parameters as well as settled solids on the corrosion of typical Al alloys used as fuel element cladding. Pitting is the main form of corrosion and is affected by water conductivity, chloride ion content, formation of galvanic couples with rack supports and settled solid particles. The extent to which these parameters influence Al corrosion varies. This paper also presents potential conversion coatings to protect the spent fuel cladding. (author)

Corrosion Resistance Behavior of Single-Layer Cathodic Arc PVD Nitride-Base Coatings in 1M HCl and 3.5 pct NaCl Solutions

Science.gov (United States)

Adesina, Akeem Yusuf; Gasem, Zuhair M.; Madhan Kumar, Arumugam

2017-04-01

The electrochemical behavior of single-layer TiN, CrN, CrAlN, and TiAlN coatings on 304 stainless steel substrate, deposited using state-of-the-art and industrial size cathodic arc PVD machine, were evaluated in 1M HCl and 3.5 pct NaCl solutions. The corrosion behavior of the blank and coated substrates was analyzed by electrochemical impedance spectroscopy (EIS), linear polarization resistance, and potentiodynamic polarization. Bond-coat layers of pure-Ti, pure-Cr, alloyed-CrAl, and alloyed-TiAl for TiN, CrN, CrAlN, and TiAlN coatings were, respectively, first deposited for improved coating adhesion before the actual coating. The average coating thickness was about 1.80 µm. Results showed that the corrosion potentials ( E corr) of the coated substrates were shifted to more noble values which indicated improvement of the coated substrate resistance to corrosion susceptibility. The corrosion current densities were lower for all coated substrates as compared to the blank substrate. Similarly, EIS parameters showed that these coatings possessed improved resistance to defects and pores in similar solution compared to the same nitride coatings developed by magnetron sputtering. The charge transfer resistance ( R ct) can be ranked in the following order: TiAlN > CrN > TiN > CrAlN in both media except in NaCl solution where R ct of TiN is lowest. While the pore resistance ( R po) followed the order: CrAlN > CrN > TiAlN > TiN in HCl solution and TiAlN > CrN > CrAlN > TiN in NaCl solution. It is found that TiAlN coating has the highest protective efficiencies of 79 and 99 pct in 1M HCl and 3.5 pct NaCl, respectively. SEM analysis of the corroded substrates in both media was also presented.

Corrosion behaviour of cladded nickel base alloys

International Nuclear Information System (INIS)

Brandl, W.; Ruczinski, D.; Nolde, M.; Blum, J.

1995-01-01

As a consequence of the high cost of nickel base alloys their use as surface layers is convenient. In this paper the properties of SA-as well as RES-cladded NiMo 16Cr16Ti and NiCr21Mo14W being produced in single and multi-layer technique are compared and discussed with respect to their corrosion behaviour. Decisive criteria describing the qualities of the claddings are the mass loss, the susceptibility against intergranular corrosion and the pitting corrosion resistance. The results prove that RES cladding is the most suitable technique to produce corrosion resistant nickel base coatings. The corrosion behaviour of a two-layer RES deposition shows a better resistance against pitting than a three layer SAW cladding. 7 refs

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Corrosion resistance of plasma-anodized AZ91D magnesium alloy by electrochemical methods

International Nuclear Information System (INIS)

Barchiche, C.-E.; Rocca, E.; Juers, C.; Hazan, J.; Steinmetz, J.

2007-01-01

Anodic coatings formed on magnesium alloys by plasma anodization process are mainly used as protective coatings against corrosion. The effects of KOH concentration, anodization time and current density on properties of anodic layers formed on AZ91D magnesium alloy were investigated to obtain coatings with improved corrosion behaviour. The coatings were characterized by scanning electron microscopy (SEM), electron dispersion X-ray spectroscopy (EDX), X-ray diffraction (XRD) and micro-Raman spectroscopy. The film is porous and cracked, mainly composed of magnesium oxide (MgO), but contains all the elements present in the electrolyte and alloy. The corrosion behaviour of anodized Mg alloy was examined by using stationary and dynamic electrochemical techniques in corrosive water. The best corrosion resistance measured by electrochemical methods is obtained in the more concentrated electrolyte 3 M KOH + 0.5 M KF + 0.25 M Na 3 PO 4 .12 H 2 O, with a long anodization time and a low current density. A double electrochemical effects of the anodized layer on the magnesium corrosion is observed: a large inhibition of the cathodic process and a stabilization of a large passivation plateau