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Creatine
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For the use of creatine to increase athletic performance, see Creatine supplements.
Not to be confused with creatinine.
Creatine
Names
Systematic IUPAC name
2-[Carbamimidoyl(methyl)amino]acetic acid
Other names
N-Carbamimidoyl-N-methylglycine; Methylguanidoacetic acid
Identifiers
CAS Number
57-00-1 Y
3D model (JSmol)
Interactive image
Interactive image
3DMet B00084
Beilstein Reference
907175
ChEBI
CHEBI:16919 N
ChEMBL
ChEMBL283800 Y
ChemSpider
566 Y
DrugBank
DB00148 Y
ECHA InfoCard 100.000.278
EC Number 200-306-6
Gmelin Reference
240513
KEGG
C00300 Y
MeSH Creatine
PubChem CID
586
RTECS number MB7706000
UNII
MU72812GK0 Y
InChI[show]
InChI=1S/C4H9N3O2/c1-7(4(5)6)2-3(8)9/h2H2,1H3,(H3,5,6)(H,8,9) Y
Key: CVSVTCORWBXHQV-UHFFFAOYSA-N Y
SMILES[show]
C[n](Cc(:[o]):[oH]):c(:[nH]):[nH2]
CN(CC(O)=O)C(N)=N
Properties
Chemical formula
C4H9N3O2
Molar mass 131.14 g·mol−1
Appearance White crystals
Odor Odourless
Melting point 255 °C (491 °F; 528 K)
Solubility in water
13.3 g L−1 (at 18 °C)
log P −1.258
Acidity (pKa) 3.429
Basicity (pKb) 10.568
Isoelectric point 8.47
Thermochemistry
Specific
heat capacity (C)
171.1 J K−1 mol−1 (at 23.2 °C)
Std molar
entropy (So298)
189.5 J K−1 mol−1
Std enthalpy of
formation (ΔfHo298)
−538.06–−536.30 kJ mol−1
Std enthalpy of
combustion (ΔcHo298)
−2.3239–−2.3223 MJ mol−1
Pharmacology
ATC code
C01EB06 (WHO)
Pharmacokinetics:
Biological half-life
3 hours
Hazards
GHS pictograms
GHS signal word WARNING
GHS hazard statements
H315, H319, H335
GHS precautionary statements
P261, P305+351+338
Related compounds
Related alkanoic acids
Sarcosine
Dimethylglycine
Glycocyamine
N-Methyl-D-aspartic acid
beta-Methylamino-L-alanine
Guanidinopropionic acid
Related compounds
Dimethylacetamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is Y N ?)
Infobox references
Creatine (/ˈkriːətiːn/ or /ˈkriːətɪn/[1][2]) is a nitrogenous organic acid that occurs naturally in vertebrates. Its main role is to facilitate recycling of adenosine triphosphate (ATP), the energy currency of the cell, primarily in muscle and brain tissue. This is achieved by recycling adenosine diphosphate (ADP) to ATP via donation of phosphate groups. Creatine also acts as a pH buffer in tissues.[3]
Creatine synthesis primarily occurs in the liver and kidneys.[3][4] On average, it is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults.[4][5] Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet.[4][6] Most of the human body's total creatine and phosphocreatine stores are found in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues.[5][6]
Creatine was identified in 1832 when Michel Eugène Chevreul isolated it from the basified water-extract of skeletal muscle. He later named the crystallized precipitate after the Greek word for meat, κρέας (kreas). In solution, creatine is in equilibrium with creatinine.[7] Creatine is a derivative of the guanidinium cation.
Contents
[hide]
1 Biosynthesis
2 Phosphocreatine system
3 Health effects
3.1 Supplements
3.2 Pharmacokinetics
3.3 Pregnancy and breastfeeding
3.4 Muscle disorders
3.5 Heterocyclic amines
3.6 Parkinson's disease
4 See also
5 References
6 External links
Biosynthesis[edit]
Creatine is not an essential nutrient[8] as it is naturally produced in the human body from the amino acids glycine and arginine. In the first step of the biosynthesis these two amino acids are combined by the enzyme arginine:glycine amidinotransferase (AGAT, EC:2.1.4.1) to form guanidinoacetate, which is then methylated by guanidinoacetate N-methyltransferase (GAMT,EC:2.1.1.2), using S-adenosyl methionine as the methyl donor. Creatine itself can be phosphorylated by creatine kinase to form phosphocreatine, which is used as an energy buffer in skeletal muscles and the brain.
Synthesis primarily takes place in the kidney and liver, with creatine then being transported to the muscles via the blood. The majority of the human body's total creatine and phosphocreatine stores are located in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues.[5][6][9] On average, creatine is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults.[4][5] Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet.[5][6] Some small studies suggest that total muscle creatine is significantly lower in vegetarians than non-vegetarians, as expected since vegetables are not a primary source of creatine. However, subjects happened to show the same levels after using supplements.[10] Given that creatine can be synthesized from the above-mentioned amino acids, protein sources rich in these amino acids can be expected to provide sufficient native biosynthesis in the body.[8]
Genetic deficiencies in the creatine biosynthetic pathway lead to various severe neurological defects.[11] Clinically, there are three distinct disorders of creatine metabolism. Deficiencies in the two synthesis enzymes can cause L-arginine:glycine amidinotransferase deficiency and guanidinoacetate methyltransferase deficiency. Both biosynthetic defects are inherited in an autosomal recessive manner. A third defect, creatine transporter defect is caused by mutations in SLC6A8 and inherited in a X-linked manner. This condition is related to the transport of creatine into the brain.[12]
Phosphocreatine system[edit]
Creatine, which is synthesized in the liver and kidneys, is transported through the blood and taken up by tissues with high energy demands, such as the brain and skeletal muscle, through an active transport system. The concentration of ATP in skeletal muscle is usually 2–5 mM, which would result in a muscle contraction of only a few seconds.[13] Fortunately, during times of increased energy demands, the phosphagen (or ATP/PCr) system rapidly resynthesizes ATP from ADP with the use of phosphocreatine (PCr) through a reversible reaction with the enzyme creatine kinase (CK). In skeletal muscle, PCr concentrations may reach 20–35 mM or more. Additionally, in most muscles, the ATP regeneration capacity of CK is very high and is therefore not a limiting factor. Although the cellular concentrations of ATP are small, changes are difficult to detect because ATP is continuously and efficiently replenished from the large pools of PCr and CK.[13] Creatine has the ability to increase muscle stores of PCr, potentially increasing the muscle’s ability to resynthesize ATP from ADP to meet increased energy demands.[14][15][16]
The pathway for the synthesis of creatine
Arg – Arginine; GATM – Glycine amidinotransferase; GAMT – Guanidinoacetate N-methyltransferase; Gly – Glycine; Met – Methionine; SAH – S-adenosyl homocysteine; SAM – S-adenosyl methionine.
The color scheme is as follows:enzymes, coenzymes and the Met part, substrate names, the Gly part, the Arg part
Health effects[edit]
Supplements[edit]
Main article: Creatine supplements
Creatine supplements are used by athletes, bodybuilders, wrestlers, sprinters, and others who wish to gain muscle mass. The Mayo Clinic states that creatine has been associated with asthmatic symptoms.[17]
A 2009 systematic review discredited concerns that creatine supplementation could affect hydration status and heat tolerance and lead to muscle cramping and diarrhea.[18][19]
There are reports of kidney damage with creatine use, such as interstitial nephritis; patients with kidney disease should avoid use of this supplement.[17] In similar manner, liver function may be altered, and caution is advised in those with underlying liver disease, although studies have shown little or no adverse impact on kidney or liver function from oral creatine supplementation.[20] In 2004 the European Food Safety Authority (EFSA) published a record which stated that oral long-term intake of 3 g pure creatine per day is risk-free.[21] A 2003 study on athletes who took creatine for 21 months found no significant changes in markers of kidney function;[22] a 2008 study on athletes who took creatine for 3 months found no evidence of kidney damage during that time.[23] A review found creatine to have no effects on liver or kidney function in over months of supplementation in both young and old population. However authors still cautioned against using high doses(>3g-5g) in those with impaired kidney functioning, and suggested further studies are needed relating to claims of mutagenicity and carcinogenicity.[24]
Long-term administration of large quantities of creatine is reported to increase the production of formaldehyde, which has the potential to cause serious unwanted side effects.[citation needed] However, this risk is largely theoretical because urinary excretion of formaldehyde, even under heavy creatine supplementation, does not exceed normal limits.[25][26]
Extensive research has shown that oral creatine supplementation at a rate of five to 20 grams per day appears to be very safe and largely devoid of adverse side-effects,[27] while at the same time effectively improving the physiological response to resistance exercise, increasing the maximal force production of muscles in both men and women.[28][29]
Many meta analyses found that creatine treatment resulted in no abnormal kidney, liver, heart, or muscle function.[30][31] It is ineffective as a treatment for amyotrophic lateral sclerosis.[32]
While some research indicates that supplementation with pure creatine is safe, a 2011 survey of 33 supplements commercially available in Italy found that over 50% of them exceeded the European Food Safety Authority recommendations in at least one contaminant. The most prevalent of these contaminants was creatinine, a breakdown product of creatine also produced by the body.[33] Creatinine was present in higher concentrations than the European Food Safety Authority recommendations in 44% of the samples. About 15% of the samples had detectable levels of dihydro-1,3,5-triazine or a high dicyandiamide concentration. Heavy metals contamination was not found to be a concern, with only minor levels of mercury being detectable. Two studies reviewed in 2007 found no impurities.[30]
Pharmacokinetics[edit]
This graph shows the mean plasma creatine concentration (measured in μmol/L) over an 8-hour period following ingestion of 4.4 grams of creatine in the form of creatine monohydrate (CrM), tri-creatine citrate (CrC), or creatine pyruvate (CrPyr).[34]
Endogenous serum or plasma creatine concentrations in healthy adults are normally in a range of 2–12 mg/L. A single 5 g (5000 mg) oral dose in healthy adults results in a peak plasma creatine level of approximately 120 mg/L at 1–2 hours post-ingestion. Creatine has a fairly short elimination half-life, averaging just less than 3 hours, so to maintain an elevated plasma level it would be necessary to take small oral doses every 3–6 hours throughout the day. After the "loading dose" period (1–2 weeks, 12–24 g a day), it is no longer necessary to maintain a consistently high serum level of creatine. As with most supplements, each person has their own genetic "preset" amount of creatine they can hold. The rest is eliminated as waste. A typical post-loading dose is 2–5 g daily.[35][36][37]
Pregnancy and breastfeeding[edit]
While research is limited, some recent retrospective studies show higher maternal serum creatine to correlate with higher birth weight and better birth outcomes. However, as of 2014, there were no randomised controlled trials establishing its effectiveness when supplemented, for neuroprotection of the fetus.
Pasteurized cow's milk contains higher levels of creatine than human milk.[38][39]
Muscle disorders[edit]
A meta analysis found that creatine treatment increased muscle strength in muscular dystrophies, and potentially improved functional performance.[40] Creatine treatment does not appear to improve muscle strength in people who have metabolic myopathies.[40] High doses of creatine leads to increased muscle pain and an impairment in activities of daily living when taken by people who have McArdle disease.[40] It has also been implicated in decreasing mutagenesis in DNA.[41]
Heterocyclic amines[edit]
When creatine is mixed with protein and sugar at high temperatures (above 148 °C), the resulting reaction produces heterocyclic amines (HCAs). Such a reaction happens when grilling or pan frying meat.[42] Creatine content (as a percentage of crude protein) can be used as an indicator of meat quality.[43]
A Meta-analysis from 2011 concluded that "search for the excretion of heterocyclic amines remains a future task to definitively exclude the unproved allegation made by some national agencies".[31]
Parkinson's disease[edit]
Creatine's impact on mitochondrial function has led to research on its efficacy and safety for slowing Parkinson's disease. The current evidence base does not provide a reliable foundation for treatment decisions, due to risk of bias, small sample sizes, and the short duration of trials.[44]
See also[edit]
Adenosine triphosphate
Beta-Alanine
Creatine phosphate
References[edit]
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Jump up ^ Wells, J. C. (2000). Longman Pronunciation Dictionary. Harlow, England: Pearson Education Ltd.
^ Jump up to: a b Barcelos RP, Stefanello ST, Mauriz JL, Gonzalez-Gallego J, Soares FA (2016). "Creatine and the Liver: Metabolism and Possible Interactions". Mini Rev Med Chem. 16 (1): 12–8. doi:10.2174/1389557515666150722102613. PMID 26202197. The process of creatine synthesis occurs in two steps, catalyzed by L-arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT), which take place mainly in kidney and liver, respectively. This molecule plays an important energy/pH buffer function in tissues, and to guarantee the maintenance of its total body pool, the lost creatine must be replaced from diet or de novo synthesis.
^ Jump up to: a b c d Brosnan JT, da Silva RP, Brosnan ME (2011). "The metabolic burden of creatine synthesis". Amino Acids. 40 (5): 1325–31. doi:10.1007/s00726-011-0853-y. PMID 21387089. Creatinine loss averages approximately 2 g (14.6 mmol) for 70 kg males in the 20- to 39-year age group. ... Table 1 Comparison of rates of creatine synthesis in young adults with dietary intakes of the three precursor amino acids and with the whole body transmethylation flux
Creatine synthesis (mmol/day) 8.3
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External links[edit]
Creatine bound to proteins in the PDB
International Society of Sports Nutrition position stand: Creatine
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text:
Rust
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about the chemical compound. For other uses, see Rust (disambiguation).
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2012) (Learn how and when to remove this template message)
Colors and porous surface texture of rust
Steels and other iron–carbon alloy phases
Ferrite
Austenite
Cementite
Graphite
Martensite
Microstructures
Spheroidite
Pearlite
Bainite
Ledeburite
Tempered martensite
Widmanstatten structures
Classes
Crucible steel
Carbon steel
Spring steel
Alloy steel
Maraging steel
Stainless steel
Weathering steel
Tool steel
Other iron-based materials
Cast iron
Gray iron
White iron
Ductile iron
Malleable iron
Wrought iron
v
t
e
Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances.[1] Rust consists of hydrated iron(III) oxides Fe2O3·nH2O and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3).
Given sufficient time, oxygen, and water, any iron mass will eventually convert entirely to rust and disintegrate. Surface rust is flaky and friable, and it provides no protection to the underlying iron, unlike the formation of patina on copper surfaces. Rusting is the common term for corrosion of iron and its alloys, such as steel. Many other metals undergo similar corrosion, but the resulting oxides are not commonly called rust.[citation needed]
Other forms of rust exist, like the result of reactions between iron and chloride in an environment deprived of oxygen. Rebar used in underwater concrete pillars, which generates green rust, is an example. Although rusting is generally a negative aspect of iron, a particular form of rusting, known as "stable rust," causes the object to have a thin coating of rust over the top, and if kept in low relative humidity, makes the "stable" layer protective to the iron below, but not to the extent of other oxides, such as aluminum.[2]
Contents
[hide]
1 Chemical reactions
1.1 Oxidation of iron
1.2 Associated reactions
2 Prevention
2.1 Rust-resistant alloys
2.2 Galvanization
2.3 Cathodic protection
2.4 Coatings and painting
2.5 Bluing
2.6 Inhibitors
2.7 Humidity control
3 Treatment
4 Economic effect
5 Cultural symbolism
6 Gallery
7 References
7.1 Further reading
8 External links
Chemical reactions
Heavy rust on the links of a chain near the Golden Gate Bridge in San Francisco; it was continuously exposed to moisture and salt spray, causing surface breakdown, cracking, and flaking of the metal.
Outdoor Rust Wedge display at the Exploratorium shows the enormous expansive force of rusting iron
Rust is another name for iron oxide,[3] which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. Although some people refer to rust generally as "oxidation", that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.
The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. If chloride ions are present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.
Oxidation of iron
When impure (cast) iron is in contact with water, oxygen, other strong oxidants, or acids, it rusts. If salt is present, for example in seawater or salt spray, the iron tends to rust more quickly, as a result of electrochemical reactions. Iron metal is relatively unaffected by pure water or by dry oxygen. As with other metals, like aluminium, a tightly adhering oxide coating, a passivation layer, protects the bulk iron from further oxidation. The conversion of the passivating ferrous oxide layer to rust results from the combined action of two agents, usually oxygen and water.
Other degrading solutions are sulfur dioxide in water and carbon dioxide in water. Under these corrosive conditions, iron hydroxide species are formed. Unlike ferrous oxides, the hydroxides do not adhere to the bulk metal. As they form and flake off from the surface, fresh iron is exposed, and the corrosion process continues until either all of the iron is consumed or all of the oxygen, water, carbon dioxide, or sulfur dioxide in the system are removed or consumed.[4]
When iron rusts, the oxides take up more volume than the original metal; this expansion can generate enormous forces, damaging structures made with iron. See economic effect for more details.
Associated reactions
The rusting of iron is an electrochemical process that begins with the transfer of electrons from iron to oxygen.[5] The iron is the reducing agent (gives up electrons) while the oxygen is the oxidising agent (gains electrons). The rate of corrosion is affected by water and accelerated by electrolytes, as illustrated by the effects of road salt on the corrosion of automobiles. The key reaction is the reduction of oxygen:
O2 + 4 e− + 2 H2O → 4 OH−
Because it forms hydroxide ions, this process is strongly affected by the presence of acid. Indeed, the corrosion of most metals by oxygen is accelerated at low pH. Providing the electrons for the above reaction is the oxidation of iron that may be described as follows:
Fe → Fe2+ + 2 e−
The following redox reaction also occurs in the presence of water and is crucial to the formation of rust:
4 Fe2+ + O2 → 4 Fe3+ + 2 O2−
In addition, the following multistep acid–base reactions affect the course of rust formation:
Fe2+ + 2 H2O ⇌ Fe(OH)2 + 2 H+
Fe3+ + 3 H2O ⇌ Fe(OH)3 + 3 H+
as do the following dehydration equilibria:
Fe(OH)2 ⇌ FeO + H2O
Fe(OH)3 ⇌ FeO(OH) + H2O
2 FeO(OH) ⇌ Fe2O3 + H2O
From the above equations, it is also seen that the corrosion products are dictated by the availability of water and oxygen. With limited dissolved oxygen, iron(II)-containing materials are favoured, including FeO and black lodestone or magnetite (Fe3O4). High oxygen concentrations favour ferric materials with the nominal formulae Fe(OH)3−xOx⁄2. The nature of rust changes with time, reflecting the slow rates of the reactions of solids.
Furthermore, these complex processes are affected by the presence of other ions, such as Ca2+, which serve as electrolytes which accelerate rust formation, or combine with the hydroxides and oxides of iron to precipitate a variety of Ca, Fe, O, OH species.
Onset of rusting can also be detected in laboratory with the use of ferroxyl indicator solution. The solution detects both Fe2+ ions and hydroxyl ions. Formation of Fe2+ ions and hydroxyl ions are indicated by blue and pink patches respectively.
Prevention
Cor-Ten is a special iron alloy that rusts, but still retains its structural integrity
Because of the widespread use and importance of iron and steel products, the prevention or slowing of rust is the basis of major economic activities in a number of specialized technologies. A brief overview of methods is presented here; for detailed coverage, see the cross-referenced articles.
Rust is permeable to air and water, therefore the interior metallic iron beneath a rust layer continues to corrode. Rust prevention thus requires coatings that preclude rust formation.
Rust-resistant alloys
See also: Stainless steel and Weathering steel
Stainless steel forms a passivation layer of chromium(III) oxide.[6][7] Similar passivation behavior occurs with magnesium, titanium, zinc, zinc oxides, aluminium, polyaniline, and other electroactive conductive polymers.[citation needed]
Special "weathering steel" alloys such as Cor-Ten rust at a much slower rate than normal, because the rust adheres to the surface of the metal in a protective layer. Designs using this material must include measures that avoid worst-case exposures, since the material still continues to rust slowly even under near-ideal conditions.[citation needed]
Galvanization
Main article: Galvanization
Interior rust in old galvanized iron water pipes can result in brown and black water.
Galvanization consists of an application on the object to be protected of a layer of metallic zinc by either hot-dip galvanizing or electroplating. Zinc is traditionally used because it is cheap, adheres well to steel, and provides cathodic protection to the steel surface in case of damage of the zinc layer. In more corrosive environments (such as salt water), cadmium plating is preferred. Galvanization often fails at seams, holes, and joints where there are gaps in the coating. In these cases, the coating still provides some partial cathodic protection to iron, by acting as a galvanic anode and corroding itself instead of the underlying protected metal. The protective zinc layer is consumed by this action, and thus galvanization provides protection only for a limited period of time.
More modern coatings add aluminium to the coating as zinc-alume; aluminium will migrate to cover scratches and thus provide protection for a longer period. These approaches rely on the aluminium and zinc oxides reprotecting a once-scratched surface, rather than oxidizing as a sacrificial anode as in traditional galvanized coatings. In some cases, such as very aggressive environments or long design life, both zinc and a coating are applied to provide enhanced corrosion protection.
Typical galvanization of steel products which are to subject to normal day to day weathering in an outside environment consists of a hot dipped 85 µm zinc coating. Under normal weather conditions, this will deteriorate at a rate of 1 µm per year, giving approximately 85 years of protection.[citation needed]
Cathodic protection
Main article: Cathodic protection
Cathodic protection is a technique used to inhibit corrosion on buried or immersed structures by supplying an electrical charge that suppresses the electrochemical reaction. If correctly applied, corrosion can be stopped completely. In its simplest form, it is achieved by attaching a sacrificial anode, thereby making the iron or steel the cathode in the cell formed. The sacrificial anode must be made from something with a more negative electrode potential than the iron or steel, commonly zinc, aluminium, or magnesium. The sacrificial anode will eventually corrode away, ceasing its protective action unless it is replaced in a timely manner.
Cathodic protection can also be provided by using a special-purpose electrical device to appropriately induce an electric charge.[8]
Coatings and painting
Main article: Rustproofing
Flaking paint, exposing a patch of surface rust on sheet metal
Rust formation can be controlled with coatings, such as paint, lacquer, or varnish that isolate the iron from the environment. Large structures with enclosed box sections, such as ships and modern automobiles, often have a wax-based product (technically a "slushing oil") injected into these sections. Such treatments usually also contain rust inhibitors. Covering steel with concrete can provide some protection to steel because of the alkaline pH environment at the steel–concrete interface. However rusting of steel in concrete can still be a problem, as expanding rust can fracture or slowly "explode" concrete from within.[citation needed]
As a closely related example, iron bars were used to reinforce stonework of the Parthenon in Athens, Greece, but caused extensive damage by rusting, swelling, and shattering the marble components of the building.[citation needed]
When only temporary protection is needed for storage or transport, a thin layer of oil, grease, or a special mixture such as Cosmoline can be applied to an iron surface. Such treatments are extensively used when "mothballing" a steel ship, automobile, or other equipment for long-term storage.
Special antiseize lubricant mixtures are available, and are applied to metallic threads and other precision machined surfaces to protect them from rust. These compounds usually contain grease mixed with copper, zinc, or aluminium powder, and other proprietary ingredients.[citation needed]
Bluing
Main article: Bluing (steel)
Bluing is a technique that can provide limited resistance to rusting for small steel items, such as firearms; for it to be successful, a water-displacing oil is rubbed onto the blued steel and other steel.
Inhibitors
Main article: Corrosion inhibitor
Corrosion inhibitors, such as gas-phase or volatile inhibitors, can be used to prevent corrosion inside sealed systems. They are not effective when air circulation disperses them, and brings in fresh oxygen and moisture.
Humidity control
See also: Dehumidifier and Desiccant
Rust can be avoided by controlling the moisture in the atmosphere.[9] An example of this is the use of silica gel packets to control humidity in equipment shipped by sea.
Treatment
Rust removal from small iron or steel objects by electrolysis can be done in a home workshop using simple materials such as a plastic bucket, tap water, lengths of rebar, washing soda, baling wire, and a battery charger.[10]
Rust may be treated with commercial products known as rust converter which contain tannic acid or phosphoric acid which combines with rust; removed with organic acids like citric acid and vinegar or the stronger hydrochloric acid; or removed with chelating agents as in some commercial formulations or even a solution of molasses.[11]
Economic effect
Main article: Corrosion
Rusting rebar has expanded and spalled concrete off the surface of this reinforced concrete support
Rust is associated with degradation of iron-based tools and structures. As rust has a much higher volume than the originating mass of iron, its buildup can also cause failure by forcing apart adjacent parts — a phenomenon sometimes known as "rust packing". It was the cause of the collapse of the Mianus river bridge in 1983, when the bearings rusted internally and pushed one corner of the road slab off its support.
Rust was an important factor in the Silver Bridge disaster of 1967 in West Virginia, when a steel suspension bridge collapsed in less than a minute, killing 46 drivers and passengers on the bridge at the time. The Kinzua Bridge in Pennsylvania was blown down by a tornado in 2003, largely because the central base bolts holding the structure to the ground had rusted away, leaving the bridge anchored by gravity alone.
Reinforced concrete is also vulnerable to rust damage. Internal pressure caused by expanding corrosion of concrete-covered steel and iron can cause the concrete to spall, creating severe structural problems. It is one of the most common failure modes of reinforced concrete bridges and buildings.
Structural failures caused by rust
The collapsed Silver Bridge, as seen from the Ohio side
The Kinzua Bridge after it collapsed
Cultural symbolism
Rust is a commonly used metaphor for slow decay due to neglect, since it gradually converts robust iron and steel metal into a soft crumbling powder. A wide section of the industrialized American Midwest and American Northeast, once dominated by steel foundries, the automotive industry, and other manufacturers, has experienced harsh economic cutbacks that have caused the region to be dubbed the "Rust Belt".
In music, literature, and art, rust is associated with images of faded glory, neglect, decay, and ruin.
Gallery
Rusted and pitted struts of the 70-year-old Nandu River Iron Bridge
Concentric rust patterns breaking through a painted surface
A leaking water pump caused severe corrosion of this engine block
A Rusted Bolivian train
A severely rusted lock
A rusted but otherwise intact Pineapple grenade that was previously buried in the ground near Opheusden, Netherlands
References
Jump up ^ "Interview, David Des Marais". NASA. 2003. Archived from the original on 2007-11-13.
Jump up ^ Ankersmit, Bart; Griesser-Stermscheg, Martina; Selwyn, Lindsie; Sutherland, Susanne. ""Rust Never Sleeps: Recognizing Metals and Their Corrosion Products"" (PDF). depotwijzer. Parks Canada. Archived (PDF) from the original on 9 August 2016. Retrieved 23 July 2016.
Jump up ^ Sund, Robert B.; Bishop, Jeanne (1980). Accent on science. C.E. Merrill. ISBN 9780675075695. Archived from the original on 2017-11-30.
Jump up ^ Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5.
Jump up ^ Gräfen, H.; Horn, E. M.; Schlecker, H.; Schindler, H. (2000). "Corrosion". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.b01_08.
Jump up ^ Ramaswamy, Hosahalli S.; Marcotte, Michele; Sastry, Sudhir; Abdelrahim, Khalid (2014-02-14). Ohmic Heating in Food Processing. CRC Press. ISBN 9781420071092.
Jump up ^ Heinz, Norbert. "Corrosion prevention - HomoFaciens". www.homofaciens.de. Retrieved 2017-11-30.
Jump up ^ "Cathodic Protection Systems - Matcor, Inc". Matcor, Inc. Archived from the original on 2017-03-30. Retrieved 2017-03-29.
Jump up ^ Gupta, Lorraine Mirza, Krishnakali. Young Scientist Series ICSE Chemistry 7. Pearson Education India. ISBN 9788131756591. Archived from the original on 2017-11-30.
Jump up ^ "Rust Removal using Electrolysis". antique-engines.com. Archived from the original on March 30, 2015. Retrieved April 1, 2015.
Jump up ^ "Rust Removal with Molasses". Archived from the original on September 25, 2016. Retrieved November 29, 2017.
Further reading
Waldman, J. (2015): Rust - the longest war. Simon & Schuster, New York. ISBN 978-1-4516-9159-7
External links
Wikimedia Commons has media related to Rust.
Look up rust in Wiktionary, the free dictionary.
corrosion case studies Analysis of corrosion
Corrosion Doctors Rusting article
Retrieved from "https://en.wikipedia.org/w/index.php?title=Rust&oldid=821297613"
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