GALVANIC/DISSIMILAR METAL CORROSION What It Is and How to Avoid It ASSDA Technical FAQ No 1 1 Edition 2, May 2009
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Environmentally Friendly Anticorrosive Polymeric Coatings
applied sciences Review Environmentally Friendly Anticorrosive Polymeric Coatings Mirko Faccini 1,* , Lorenzo Bautista 2, Laura Soldi 2, Ana M. Escobar 2 , Manuela Altavilla 1, Martí Calvet 2 , Anna Domènech 2 and Eva Domínguez 2 1 Centro de Excelencia en Nanotecnología (CEN), Leitat Chile, Calle Román Díaz 532, Providencia, Santiago 7500724, Chile; [email protected] 2 Leitat Technological Center, Surface Chemistry Area, Applied Chemistry & Materials Department, Terrassa 08225, Barcelona, Spain; [email protected] (L.B.); [email protected] (L.S.); [email protected] (A.M.E.); [email protected] (M.C.); [email protected] (A.D.); [email protected] (E.D.) * Correspondence: [email protected] Abstract: This paper provides a synthetic and comprehensive overview on environmentally friendly anticorrosive polymeric coatings. Firstly, the economic and environmental impact of corrosion is presented to highlight the need of anticorrosive polymeric coatings as a flexible and effective solution to protect a metal. Secondly, the implementation of regulations together with the consumer awareness for environmental considerations and protection of health are the driving force for a progressive but significant change in the sector. Therefore, within the protective organic coatings market, this article provides a review of the most recent developments in environmentally friendly solutions, including bio-based and water-borne epoxy, hyperbranched polyester for low- volatile organic compounds (VOC) coatings, waterborne polyurethane and non-isocyanate polyurethanes (NIPUs), and graphene or bio-based fillers for acrylics. Moreover, this paper outlines new trends such as smart additives, bio- based corrosion inhibitors, and functional antibiocorrosive coatings as superhydrophobics. Finally, Citation: Faccini, M.; Bautista, L.; industrially relevant applications of environmentally friendly anticorrosive polymeric coatings Soldi, L.; Escobar, A.M.; Altavilla, M.; including solutions for marine and off-shore industries are summarized. -
Development of a Low Resistance Low Corrosion Cathode Plate
Development of a low resistance, low corrosion cathode plate for electrowinning and electrorefining Nigel J. Aslin1*1, Christian Pasten2, Addin Pranowo3, Graham J. Heferen4 1. Glencore Technology, Australia ABSTRACT For nearly 40 years Glencore Technology (formerly Mount Isa Mines Copper Refineries) has been the mainstay supplier of permanent cathode plates to the copper industry with its ISA PROCESS and KIDD PROCESS cathode plates. Improvement to the cathode plate design remains a key area for research, and on-going developments by Glencore Technology have led to the commercialisation of a new design. The ISAKIDD cathode plate is universally suited to both electro-refining and electro- winning bringing major cost efficiencies to the operations through improvements in hanger bar strength, corrosion resistance and electrical conductivity. A variation of the this design uses a ‘steer- horn’ shaped hanger bar to lower the resistance path across the cathode plate giving significant tank- house power savings in electrowinning refineries. Technical aspects and results of commercial trials of the ISAKIDD and ‘HP’ cathode plate are discussed in this paper. A novel new contact system which allows shorting frames to be used with Stainless Steel hanger bars will also be tested. Trial results will demonstrate savings in a typical EW tankhouse of up to 720k USD per year in power costs alone, with further savings in maintenance costs and operational efficiencies. *Corresponding author: Glencore Technology, Technical Manager, c/- Copper Refineries Pty Ltd, Hunter St, Stuart, 4811, QLD, Australia. Phone: +61 418887034. Email: [email protected] 1 INTRODUCTION Glencore Technology were the pioneers of Permanent cathode technology for copper and remain committed to continuous improvement and innovation of the technology forty years later. -
Galvanic Corrosion
10 GALVANIC CORROSION X. G. ZHANG Teck Metals Ltd., Mississauga, Ontario, Canada A. Introduction graphite, are dispersed in a metal, or on a ship, where the B. Definition various components immersed in water are made of different C. Factors in galvanic corrosion metal alloys. In many cases, galvanic corrosion may result in D. Material factors quick deterioration of the metals but, in other cases, the D1. Effects of coupled materials galvanic corrosion of one metal may result in the corrosion D2. Effect of area protection of an attached metal, which is the basis of cathodic D3. Effect of surface condition protection by sacrificial anodes. E. Environmental factors Galvanic corrosion is an extensively investigated subject, E1. Effects of solution as shown in Table 10.1, and is qualitatively well understood E2. Atmospheric environments but, due to its highly complex nature, it has been difficult to E3. Natural waters deal with in a quantitative way until recently. The widespread F. Polarity reversal use of computers and the development of software have made G. Preventive measures great advances in understanding and predicting galvanic H. Beneficial effects of galvanic corrosion corrosion. I. Fundamental considerations I1. Electrode potential and Kirchhoff’s law I2. Analysis B. DEFINITION I3. Polarization and resistance I4. Potential and current distributions When two dissimilar conducting materials in electrical con- References tact with each other are exposed to an electrolyte, a current, called the galvanic current, flows from one to the other. Galvanic corrosion is that part of the corrosion that occurs at the anodic member of such a couple and is directly related to the galvanic current by Faraday’s law. -
Galvanic Corrosion Final
GALVANIC CORROSION by Stephen C. Dexter, Professor of Applied Science and Marine Biology, (302) 645-4261 Galvanic corrosion, often misnamed “electrolysis,” is one common form of corrosion in marine environments. It occurs Table 1 when two (or more) dissimilar metals are brought into electri- GALVANIC SERIES cal contact under water. When a galvanic couple forms, one of In Flowing Seawater the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode Voltage Range of Alloy and corrodes slower than it would alone. Either (or both) metal Alloy vs. Reference Electrode* in the couple may or may not corrode by itself (themselves) in MagnesiumAnodic or -1.60 to -1.63 seawater. When contact with a dissimilar metal is made, how- Active End ever, the self-corrosion rates will change: corrosion of the Zinc -0.98 to -1.03 anode will accelerate; corrosion of the cathode will decelerate Aluminum Alloys -0.70 to -0.90 or even stop. We can use the seawater Galvanic Series, shown Cadmium -0.70 to -0.76 in Table 1, to predict which metal will become the anode and Cast Irons -0.60 to -0.72 how rapidly it will corrode. Steel -0.60 to -0.70 Aluminum Bronze -0.30 to -0.40 The seawater Galvanic Series is a list of metals and alloys Red Brass, Yellow Brass, ranked in order of their tendency to corrode in marine environ- Naval Brass -0.30 to -0.40 ments. If any two metals from the list are coupled together, the Copper -0.28 to -0.36 one closer to the anodic (or active) end of the series, the Lead-Tin Solder (50/50) -0.26 to -0.35 upper end in this case, will be the anode and thus will corrode Admiralty Brass -0.25 to -0.34 faster, while the one toward the cathodic (or noble) end will Manganese Bronze -0.25 to -0.33 corrode slower. -
Material for Teachers
For Teachers How Best to Maintain a Metal Bridge? Teacher Guide This decision making exercise is intended to reinforce previous knowledge on rusting. It introduces through simple laboratory experiments, which students can plan (if the students are unaware), the need for oxygen and water to be present for rusting to occur. The exercise also allows students to explore the use of a sacrificial metal to protect iron and includes theoretical understanding of reactions between dissimilar metals (depending on the conceptual level required by the curriculum). As a major aspect of the script, a decision making exercise is introduced. Students are called upon to reflect on factors (besides scientific ideas) that need to be taken into account in making a decision on the most appropriate way to protect a metal bridge. This may range from doing nothing - the cheapest, to galvanising it - a scientific answer. In between could be environmental, economic or societal solutions. All are possibilities, but the difficulty is to decide which is the most appropriate and then to explain the choice. Lesson Learning Outcomes Lesson 1 At the end of this lesson, students are expected to be able to: • State that iron rusts • Suggest ways to investigate the factors that cause iron to rust Lesson 2 At the end of this lesson, students are expected to be able to: • Undertake and understand experiments that can be performed to show the factors that cause iron to rust Developer: Jack Holbrook Institute: ICASE Country: UK Lesson 3 At the end of this lesson, students are expected to be able to: • Explain why oxygen and water are needed for iron to rust • Suggest a formula for rust Lesson 4 At the end of this lesson, students are expected to be able to : • Suggest experimental procedures to determine the sacrificial metal when two metals are put together • Predict the likely outcome when metals are put together in an atmosphere that prvides both oxygen and water. -
Galvanneal Zinc Coating – Paintable & Weldable Galvanized
Specifications Prime Steel Designations & Weights Engineering Data WIZcoat™ galvannealed strut is pro- WIZcoat™ galvannealed strut is pro- Galvannealed G-Strut® is produced duced from prime, hot-rolled carbon duced from steel that is designed to from hot roll carbon steel (ASTM 570) to steel substrate. Material conforms to meet requirements for forming, draw- the following mill certification physical/ the ASTM A653 specification and is ing, bending, welding and painting mechanical properties. Average yield produced from structural grade steel – conforming to designations and test strength: 42,700 pounds; Average ten- (See Engineering Data.) limits in accordance with provisions of sile strength, 62,600 pounds; Average Rockwell B (RB Value) range: 62 – 74. Produced on Gregory’s own specialty ASTM A653. Modified Sendzimir Hot-Dip Galvanizing Finish ISO CERTS - Quality Control Line, coils are alkaline-cleaned, pickled The silvery matte finish and low reflec- Gregory Industries upholds the highest and galvannealed in one continuous tivity of galvannealed coatings provides industry standards, conforming to and process. excellent weldability and paint-adher- maintaining ISO 9001; 2000 – ANSI/ Galvanneal Zinc Coating Paintability ence properties without special surface ISO/ASQ Q9001-2000 certification for the manufacture and supply of galva- WIZcoat™ galvannealed strut is designed treatment. – Paintable & Weldable Galvanized – nized steel coils. [Certificate # 112358- for superior paint adhesion. The process Galvannealed Coating Specs. 0, registration # 1132-01]. induces an ideal surface that is a zinc (Standard & metric) alloy well suited to painting. The resulting Galvannealed Minimum Minimum Minimum G-STRUT® benefits from this detailed surface forms microscopic crevices that Coating Triple Spot Triple Spot Single Spot QC process. -
Corrosion Protection of Metal Connectors in Coastal Areas
Corrosion Protection for Metal Connectors and Fasteners in Coastal Areas in Accordance with the National Flood Insurance Program NFIP Technical Bulletin 8 / June 2019 Comments on the Technical Bulletins should be directed to: DHS/FEMA Federal Insurance and Mitigation Administration (FIMA) Risk Management Directorate Building Science Branch 400 C Street, S.W., Sixth Floor Washington, DC 20472-3020 Technical Bulletin 8 (2019) replaces Technical Bulletin 8 (1996), Corrosion Protection for Metal Connectors in Coastal Areas for Structures Located in Special Flood Hazard Areas in accordance with the National Flood Insurance Program. Cover photographs: Inset photo: Corrosion of galvanized connectors (FEMA, Fire Island, NY, after Hurricane Sandy). Outset photo: Longer strap connectors helped maintain the connection between the beam and floor joists (FEMA, Seaside Heights, NJ, after Hurricane Sandy).. NFIP Technical Bulletin 8 contains information that is proprietary to and copyrighted by the American Society of Civil Engineers and information that is proprietary to and copyrighted by the International Code Council, Inc. All information is used with permission. For more information, see the FEMA Building Science Frequently Asked Questions website at http://www.fema.gov/ To order publications, contact the FEMA frequently-asked-questions-building-science. Distribution Center: Call: 1-800-480-2520 If you have any additional questions on FEMA Building (Monday–Friday, 8 a.m.–5 p.m., EST) Science Publications, contact the helpline at FEMA- Fax: 719-948-9724 [email protected] or 866-927-2104. Email: [email protected] You may also sign up for the FEMA Building Science email Additional FEMA documents can be subscription, which is updated with publication releases found in the FEMA Library at and FEMA Building Science activities. -
Corrosion Basics
CORROSION BASICS (from Swain (1996) and Schultz (1997)) What is corrosion? • Webster’s Dictionary - corrode (v.) To eat away or be eaten away gradually, especially by chemical action. • NACE Corrosion Basics - corrosion may be defined as the deterioration of a material (usually a metal) because of a reaction with the environment. Why do metals corrode? Most metals are found in nature as ores. The manufacturing process of converting these ores into metals involves the input of energy. During the corrosion reaction the energy added in manufacturing is released, and the metal is returned to its oxide state. Metal Ore reduction (add electrons)→ Metal oxidation (strip electrons)→ Corrosion Products In the marine environment, the corrosion process generally takes place in aqueous solutions and is therefore electrochemical in nature. Corrosion consequences Economic - corrosion results in the loss of $8 - $126 billion annually in the U.S. alone. This impact is primarily the result of: 1. Downtime 2. Product Loss 3. Efficiency Loss 4. Contamination 5. Overdesign Safety / Loss of Life Corrosion can lead to catastrophic system failures which endanger human life and health. Examples include a 1967 bridge collapse in West Virginia which killed 46. The collapse was attributed to stress corrosion cracking (SCC). In another example, the fuselage of an airliner in Hawaii ripped open due to the combined action of stress and atmospheric corrosion. Corrosion cell Corrosion occurs due to the formation of electrochemical cells. In order for the corrosion reaction to occur five things are necessary. If any of these factors are eliminated, galvanic corrosion will not occur. THIS IS THE KEY TO CORROSION CONTROL! The necessary factors for corrosion to proceed are: 1. -
A New Versatile Concept in Cathodic Protection
® A New Versatile Concept in Cathodic Protection Developed and Patented by NASA N M V I R O E N T N A L E S Y E D S T E R E M R E G I S T A New Type of Galvanic Protection Developed and Patented by NASA A new reinforced concrete structure is designed to have a long service life – typically in excess of 50 years. Unfortunately, many structures fall short of this goal, requiring expensive repair and protection work in the future. A major reason for the premature deterioration of our reinforced concrete infrastructure is corrosion of the reinforced steel. Galvanic protection of embedded steel rebar for existing structures. Suppresses corrosion in carbonated and chloride-contaminated concrete. Extends life of concrete structures. Galvanic protection of embedded steel rebar for existing structures. Suppresses corrosion in carbonated and chloride contaminated concrete and extends life. Since GalvaCorr® is 90% metal, GalvaCorr® is a three component moisture cured metallic rich scratching the surface of the coating. The new coating provides cathodic protection and when coating will reveal connected to the steel rebar galvanically stops corrosion. a metallic sheen. • Can be applied by spray, brush or roll coating. • Recommended for bridges, decks, ramps and garages. • Can be applied to uneven surfaces and to the underside of structures. The use of a sacrificial metal to protect another metal goes back a century. This proven technology has been used in many forms. Now there is a new form available to protect the embedded steel rebars in concrete structures. Note rust bubbling GalvaCorr® is a room temperature liquid coating that can be out at the base of sprayed or hand applied to concrete structures. -
Bimetallic Corrosion
Guides to Good Practice in Corrosion Control No. 5 Bimetallic Corrosion Corrosion Research and Testing For more information on corrosion research and testing contact [email protected] Or visit our website: www.npl.co.uk/electrochemistry National Corrosion Service The National Corrosion Service (NCS) is operated by NPL on behalf of the National Measurement System to provide a gateway to corrosion and materials expertise for UK users. By acting as a focal point for corrosion enquiries the NCS can make the UK’s entire base of experts available to solve problems or can use in-house expertise or teams to carry out consultancy. The NCS also raises awareness of corrosion problems and methods of control. For more information on NCS services and products please contact us at: [email protected] A free advice service is available to UK Residents and Companies on materials and general corrosion related matters. You can also contact the NCS by phone on 020 8943 6142. This is an update of a Department of Trade and Industry publication first issued in 1982. The new version has been prepared by Dr. R. Francis of RF Materials under contract from NPL for the Department of Business, Energy and Industrial Strategy. Edited by Dr. A Turnbull and Dr. G. Hinds, NPL. Although every effort is made to ensure that the information contained in this document is accurate and up to date, NPL does not make any representations or warranties, whether express, implied by law or by statute, as to its accuracy, completeness or reliability. NPL excludes all liabilities arising from the use of this brochure to the fullest extent permissible by law. -
19. the Galvanic (Electrochemical) Series
19. THE GALVANIC (ELECTROCHEMICAL) SERIES INTRODUCTION All conductive elements (all metals) have different electrical potentials. These electrical potentials put each metal in a hierarchy of activity, with the most active metals at the top of the lists, and the least active at the bottom. This order of electrochemical activity is called the Galvanic Series. A metal higher in the Galvanic Series will corrode preferentially to a metal below it in the Series. The greater the distance apart the metals are in the Galvanic Series, the higher the current that will fl ow between them if they are connected in the presence of an electrolyte (a conducting solution; usually water containing dissolved salts). Some metals like aluminium and zinc develop tough oxide fi lms. These fi lms give them exceptionally good corrosion resistance, although they are among the most active metals. The position of zinc on the Galvanic Series, above most other metals, means that it will corrode preferentially if it contacts any of these metals and moisture is present. This characteristic of zinc is an important part of its exceptional performance in protecting steel from corrosion. Many steel products are galvanized using continuous galvanizing processes. These semi-fabricated steel items (columns, beams, angles etc.) are subject to further processes like slitting, cutting, drilling, punching and welding. This leaves the steel uncoated on cut edges and other areas damaged by processing. The galvanic protection provided by the adjacent zinc coating provides these steel products with their anti-corrosion performance, otherwise rapid corrosion would occur on these exposed areas. A counter example occurs with chrome-plated steel. -
Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM
metals Article Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM Armen Kvryan, Kari Livingston, Corey M. Efaw, Kyle Knori, Brian J. Jaques, Paul H. Davis, Darryl P. Butt and Michael F. Hurley * Department of Materials Science and Engineering, College of Engineering, Boise State University, Boise, ID 83725-2090, USA; [email protected] (A.K.); [email protected] (K.L.); [email protected] (C.M.E.); [email protected] (K.K.); [email protected] (B.J.J.); [email protected] (P.H.D.); [email protected] (D.P.B.) * Correspondence: [email protected]; Tel.: +1-208-426-4075 Academic Editors: Vineet V. Joshi and Alan Meier Received: 3 February 2016; Accepted: 6 April 2016; Published: 19 April 2016 Abstract: The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM) was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS) measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 M NaCl, corrosion occurred at the braze-316L interface preceded by preferential dissolution of the Cu-rich phase within the braze alloy. Braze corrosion was driven by galvanic couples between the braze alloys and stainless steel as well as between different phases within the braze microstructure.