A corrosion inhibitor or anti-corrosive is a chemical compound added to a liquid or gas to decrease the corrosion rate of a metal that comes into contact with the fluid.[1] The effectiveness of a corrosion inhibitor depends on fluid composition and dynamics. Corrosion inhibitors are common in industry, and also found in over-the-counter products, typically in spray form in combination with a lubricant and sometimes a penetrating oil. They may be added to water to prevent leaching of lead or copper from pipes.[2]
A common mechanism for inhibiting corrosion involves formation of a coating, often a passivation layer, which prevents access of the corrosive substance to the metal. Permanent treatments such as chrome plating are not generally considered inhibitors, however: corrosion inhibitors are additives to the fluids that surround the metal or related object.
Benzotriazole inhibits corrosion of copper by forming an inert layer of this polymer on the metal's surface
The nature of the corrosive inhibitor depends on (i) the material being protected, which are most commonly metal objects, and (ii) on the corrosive agent(s) to be neutralized. The corrosive agents are generally oxygen, hydrogen sulfide, and carbon dioxide. Oxygen is generally removed by reductive inhibitors such as amines and hydrazines:
Boilers. Volatile amines are added to boiler water to minimize the effects of acid. In some cases, the amines form a protective film on the steel surface and, at the same time, act as an anodic inhibitor. An inhibitor that acts both in a cathodic and anodic manner is termed a mixed inhibitor.
Copper surfaces. Benzotriazole is used to inhibit the corrosion and staining of.[5]
Paint. A pigment with anticorrosive properties is zinc phosphate. Compounds derived from tannic acid or zinc salts of organonitrogens (e.g. Alcophor 827) can be used together with anticorrosive pigments. Other corrosion inhibitors are Anticor 70, Albaex, Ferrophos, and Molywhite MZAP.
Corrosion of tap water pipes can be influenced by a number of factors such as the pH, buffering capacity, and hardness.[6] Methods of control include directly adjusting the pH, adding phosphates, silicates as an alternative corrosion inhibitor, or adding bicarbonates for buffer.[2]
Orthophosphates may be added in tap watertreatment systems to prevent leaching of lead and copper from water pipes and reduce the ion content in tap water to safer, legal levels.[2]Polyphosphates can be used to control iron and manganese, which cause discoloration, but do not control lead and copper. The water industry commonly uses a blended-phosphates formulation to deal with both issues.[7] Phosphates convert any leached ions into a layer of scale that acts to separate the metal piping from the water.[8]
Phosphate-type inhibitors may cause eutrophication issues downstream or directly encourage algal growth in uncovered, treated water reservoirs. As a result, local water systems may elect to use alternative methods.[9]
In areas with widespread lead and copper piping systems, corrosion control using inhibitors and monitoring techniques is central to water safety. Figures such as the chloride-to-sulfate mass ratio (CSMR) can be used to estimate the risk of corrosion at galvanic connections (i.e. desimilar pipe/solder connections, such as a lead-to-iron transition). The 2014 Flint water crisis was caused by a combination of source water change and a lack of corrosion control. The new, higher-CSMR water not only dissolved lead and iron from the pipes themselves, but also broke up previous layers of lead-containing rusty scale in pipes, allowing them to enter the water supply.[8]
Fuel additivesedit
DCI-4A, widely used in commercial and military jet fuels, acts also as a lubricity additive. Can be also used for gasolines and other distillate fuels.
"Corrosion Resistance - DECC Company". www.decc.com. Retrieved 2015-10-15.*"Nitriding for Corrosion and Wear Fatigue Resistance". Corrosionpedia. Retrieved 2018-06-19.
Referencesedit
^Hubert Gräfen, Elmar-Manfred Horn, Hartmut Schlecker, Helmut Schindler "Corrosion" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim, 2002. doi:10.1002/14356007.b01_08
^ abc"Optimal Corrosion Control Treatment Evaluation Technical Recommendations for Primacy Agencies and Public Water Systems" (PDF). United States Environmental Protection Agency. 2019.
^Ma, I. A. Wonnie; Ammar, Sh.; Kumar, Sachin S. A.; Ramesh, K.; Ramesh, S. (2022-01-01). "A concise review on corrosion inhibitors: types, mechanisms and electrochemical evaluation studies". Journal of Coatings Technology and Research. 19 (1): 241–268. doi:10.1007/s11998-021-00547-0. ISSN 1935-3804. S2CID 244716439.
^M. Finšgarand and I. Milošev "Inhibition of copper corrosion by 1,2,3-benzotriazole: A review" Corrosion Science 2010, Volume 52, Pages 2737-2749 doi:10.1016/j.corsci.2010.05.002
^"Drinking Water Pipe Systems | Engineering | Community Water Fluoridation | Division of Oral Health | CDC". www.cdc.gov. 5 November 2018.
^"Why do water systems add phosphate to drinking water? What are the health effects of drinking water containing phosphates?". EPA.gov. 2 March 2023.
^ abPieper, Kelsey J.; Tang, Min; Edwards, Marc A. (21 February 2017). "Flint Water Crisis Caused By Interrupted Corrosion Control: Investigating "Ground Zero" Home". Environmental Science & Technology. 51 (4): 2007–2014. Bibcode:2017EnST...51.2007P. doi:10.1021/acs.est.6b04034. PMID 28145123. S2CID 26186807.
^The Cadmus Group, Inc. (July 22, 2004). "Investigation of Potential Environmental Impacts due to the use of Phosphate-based Corrosion Inhibitors in the District of Columbia" (PDF). archive.epa.gov.
External linksedit
, Norman Hackerman,(August, 2006), Electrochemistry Encyclopedia[dead link]
May 15, 2024
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A corrosion inhibitor or anti corrosive is a chemical compound added to a liquid or gas to decrease the corrosion rate of a metal that comes into contact with the fluid 1 The effectiveness of a corrosion inhibitor depends on fluid composition and dynamics Corrosion inhibitors are common in industry and also found in over the counter products typically in spray form in combination with a lubricant and sometimes a penetrating oil They may be added to water to prevent leaching of lead or copper from pipes 2 A common mechanism for inhibiting corrosion involves formation of a coating often a passivation layer which prevents access of the corrosive substance to the metal Permanent treatments such as chrome plating are not generally considered inhibitors however corrosion inhibitors are additives to the fluids that surround the metal or related object Contents 1 Types 2 Applications 2 1 Tap water 2 2 Fuel additives 3 See also 4 External links 5 References 6 External linksTypes edit nbsp Benzotriazole inhibits corrosion of copper by forming an inert layer of this polymer on the metal s surface The nature of the corrosive inhibitor depends on i the material being protected which are most commonly metal objects and ii on the corrosive agent s to be neutralized The corrosive agents are generally oxygen hydrogen sulfide and carbon dioxide Oxygen is generally removed by reductive inhibitors such as amines and hydrazines O2 N2H4 2 H2O N2 In this example hydrazine converts oxygen a common corrosive agent to water which is generally benign Related inhibitors of oxygen corrosion are hexamine phenylenediamine and dimethylethanolamine and their derivatives Antioxidants such as sulfite and ascorbic acid are sometimes used Some corrosion inhibitors form a passivating coating on the surface by chemisorption Benzotriazole is one such species used to protect copper For lubrication zinc dithiophosphates are common they deposit sulfide on surfaces The suitability of any given chemical for a task in hand depends on many factors including their operating temperature 3 Applications editCorrosion inhibitors are commonly added to Coolants Fuels Some components include zinc dithiophosphates 4 Hydraulic fluids Engine oil Boilers Volatile amines are added to boiler water to minimize the effects of acid In some cases the amines form a protective film on the steel surface and at the same time act as an anodic inhibitor An inhibitor that acts both in a cathodic and anodic manner is termed a mixed inhibitor Copper surfaces Benzotriazole is used to inhibit the corrosion and staining of 5 Paint A pigment with anticorrosive properties is zinc phosphate Compounds derived from tannic acid or zinc salts of organonitrogens e g Alcophor 827 can be used together with anticorrosive pigments Other corrosion inhibitors are Anticor 70 Albaex Ferrophos and Molywhite MZAP Oil field industry Antiseptics such as benzalkonium chloride are used to counter microbial corrosion Oil refineries Corrosive hydrogen sulfide is removed using air and amines by conversion to polysulfides Tap water edit Corrosion of tap water pipes can be influenced by a number of factors such as the pH buffering capacity and hardness 6 Methods of control include directly adjusting the pH adding phosphates silicates as an alternative corrosion inhibitor or adding bicarbonates for buffer 2 Orthophosphates may be added in tap water treatment systems to prevent leaching of lead and copper from water pipes and reduce the ion content in tap water to safer legal levels 2 Polyphosphates can be used to control iron and manganese which cause discoloration but do not control lead and copper The water industry commonly uses a blended phosphates formulation to deal with both issues 7 Phosphates convert any leached ions into a layer of scale that acts to separate the metal piping from the water 8 Phosphate type inhibitors may cause eutrophication issues downstream or directly encourage algal growth in uncovered treated water reservoirs As a result local water systems may elect to use alternative methods 9 In areas with widespread lead and copper piping systems corrosion control using inhibitors and monitoring techniques is central to water safety Figures such as the chloride to sulfate mass ratio CSMR can be used to estimate the risk of corrosion at galvanic connections i e desimilar pipe solder connections such as a lead to iron transition The 2014 Flint water crisis was caused by a combination of source water change and a lack of corrosion control The new higher CSMR water not only dissolved lead and iron from the pipes themselves but also broke up previous layers of lead containing rusty scale in pipes allowing them to enter the water supply 8 Fuel additives edit DCI 4A widely used in commercial and military jet fuels acts also as a lubricity additive Can be also used for gasolines and other distillate fuels DCI 6A for motor gasoline and distillate fuels and for U S military fuels JP 4 JP 5 JP 8 DCI 11 for alcohols and gasolines containing oxygenates DCI 28 for very low pH alcohols and gasolines containing oxygenates DCI 30 for gasoline and distillate fuels excellent for pipeline transfers and storage caustic resistant DMA 4 solution of alkylaminophosphate in kerosene for petroleum distillatesSee also editCathodic Protection for Vehicles Corrosion Cosmoline CRC Corrosion Inhibitor 5 56 Hot dip galvanizing Iron pillar of Delhi Marvel Mystery Oil Mexel Oil additive Tinning Truscon Laboratories Volatile corrosion inhibitor Rust converterExternal links edit What is corrosion resistance www corrosionist com Archived from the original on 2016 03 04 Retrieved 2015 10 15 Engineering ToolBox www engineeringtoolbox com Retrieved 2015 10 15 Protective Coatings and Inorganic Anti Corrosion Pigments www astm org Retrieved 2015 10 15 Electro Galvanized Steel Rolled Steel Products Rolled Steel Products www rolledsteel com Retrieved 2015 10 15 Anti corrosion coatings www performancecoatings org Retrieved 2018 06 25 Corrosion Resistance DECC Company www decc com Retrieved 2015 10 15 Nitriding for Corrosion and Wear Fatigue Resistance Corrosionpedia Retrieved 2018 06 19 References edit Hubert Grafen Elmar Manfred Horn Hartmut Schlecker Helmut Schindler Corrosion Ullmann s Encyclopedia of Industrial Chemistry Wiley VCH Weinheim 2002 doi 10 1002 14356007 b01 08 a b c Optimal Corrosion Control Treatment Evaluation Technical Recommendations for Primacy Agencies and Public Water Systems PDF United States Environmental Protection Agency 2019 Ma I A Wonnie Ammar Sh Kumar Sachin S A Ramesh K Ramesh S 2022 01 01 A concise review on corrosion inhibitors types mechanisms and electrochemical evaluation studies Journal of Coatings Technology and Research 19 1 241 268 doi 10 1007 s11998 021 00547 0 ISSN 1935 3804 S2CID 244716439 Octel Starreon Refinery Fuel Additives Corrosion Inhibitors for hydrocarbon fuels corrosion inhibitor and corrosion protection to fuel distribution system M Finsgarand and I Milosev Inhibition of copper corrosion by 1 2 3 benzotriazole A review Corrosion Science 2010 Volume 52 Pages 2737 2749 doi 10 1016 j corsci 2010 05 002 Drinking Water Pipe Systems Engineering Community Water Fluoridation Division of Oral Health CDC www cdc gov 5 November 2018 Why do water systems add phosphate to drinking water What are the health effects of drinking water containing phosphates EPA gov 2 March 2023 a b Pieper Kelsey J Tang Min Edwards Marc A 21 February 2017 Flint Water Crisis Caused By Interrupted Corrosion Control Investigating Ground Zero Home Environmental Science amp Technology 51 4 2007 2014 Bibcode 2017EnST 51 2007P doi 10 1021 acs est 6b04034 PMID 28145123 S2CID 26186807 The Cadmus Group Inc July 22 2004 Investigation of Potential Environmental Impacts due to the use of Phosphate based Corrosion Inhibitors in the District of Columbia PDF archive epa gov External links editCorrosion control informations and documents Developing corrosion inhibitor models A paper on corrosion inhibition modeling Corrosion inhibition Norman Hackerman August 2006 Electrochemistry Encyclopedia dead link Retrieved from https en wikipedia org w index php title Corrosion inhibitor amp oldid 1209508250, wikipedia, wiki, book, books, library,
