Did you mean: rust (in botany), rust fungus, rust (comics), Bernhard Rust, Rust (color), Mathias Rust, Rod Rust, Wilhelm Rust, Donald L. Rust, Joel Rust

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rust

  (rŭst) pronunciation
n.
  1. Any of various powdery or scaly reddish-brown or reddish-yellow hydrated ferric oxides formed on iron and iron-containing materials by low-temperature oxidation in the presence of water.
  2. Any of various metallic coatings, especially oxides, formed by corrosion.
  3. A stain or coating resembling iron rust.
  4. Deterioration, as of ability, resulting from inactivity or neglect.
  5. Botany.
    1. Rust fungus.
    2. A plant disease caused by a rust fungus, characterized by reddish or brownish spots on leaves, stems, and other parts.
  6. A strong brown.

v., rust·ed, rust·ing, rusts.

v.intr.
  1. To become corroded.
  2. To deteriorate or degenerate through inactivity or neglect.
  3. To become the color of rust.
  4. Botany. To develop a disease caused by a rust fungus.
v.tr.
  1. To corrode or subject (a metal) to rust formation.
  2. To impair or spoil, as by misuse or inactivity.
  3. To color (something) a strong brown.

[Middle English, from Old English rūst.]

rust rust adj.
rustable rust'a·ble adj.
 
 

Plant diseases caused by fungi of the order Uredinales and characterized by the powdery and usually reddish spores produced. There are more than 4000 species of rust fungi. All are obligate parasites (require a living host) in nature, and each species attacks only plants of particular genera or species. Morphologically identical species that attack different host genera are further classified as special forms (formae speciales); for example, Puccinia graminis f. sp. tritici attacks wheat and P. graminis f. sp. hordei attacks barley. Each species or special form can have many physiological races that differ in their ability to attack different cultivars (varieties) of a host species. Rusts are among the most destructive plant diseases. Economically important examples include wheat stem rust, white pine blister rust, and coffee rust. See also Uredinales.

Rust fungi have complex life cycles, producing up to five different fruiting structures with distinct spore types that appear in a definite sequence. Macrocyclic (long-cycled) rust fungi produce all five spore types, whereas microcyclic (short-cycled) rust fungi produce only teliospores and basidiospores. Some macrocyclic rust fungi complete their life cycle on a single host and are called autoecious, whereas others require two different or alternate hosts and are called heteroecious. See also Fungi; Plant pathology.


 

A substance, usually in powder form, of light brownish red color, accumulating on the face of steel or iron as a result of oxidation; ultimately weakens or destroys the steel or iron on which it is allowed to form.


 
in botany, name for various parasitic fungi of the order Uredinales and for the diseases of plants that they cause. Rusts form reddish patches of spores on the host plant. About 7,000 species are known. Some grow entirely on one plant; others require two hosts, plants of two species, in order to complete their life cycles. Cedar rust, for instance, grows on cedar and on apple trees, needing both for development. Blister rust of pine grows on pines and either currant or gooseberry bushes. Black stem rust Puccinia graminis is one of the most destructive to wheat, rye, and other grasses; barberry is an alternate host. Rusts attack all cereal crops and many fruits, vegetables, forage crops, ornamental plants, and forest trees. Rusts are hard to eradicate; control measures include the use of rust-resistant varieties of seed and the elimination of alternate hosts in agricultural areas. Rusts are classified in the kingdom Fungi, phylum (division) Basidiomycota, order Uredinales.


 

1. a disease of tropical fish in aquariums caused by the protozoa Oodinium limneticum and characterized by loss of luster of the skin surface. Causes heavy mortality.
2. a bacterial disease of the shell in turtles. See also shell rot.

 

Any of a number of fungal diseases that cause rusty-looking spots on leaves or stems, particularly in cool damp weather.

 
pronunciation

IN BRIEF: The orange-red coating that forms on metal surfaces because of the oxidation of the iron in their contents due to exposure to air and water.

pronunciation Everyone needs a warm, personal enemy or two to keep him free of rust in the movable parts of his mind. — Gene Fowler

 
Wikipedia: rust


Rusted bolt
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Rusted bolt
A blacksmith removing rust with sand prior to welding
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A blacksmith removing rust with sand prior to welding
Rust damage in automobiles can create hidden dangers.
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Rust damage in automobiles can create hidden dangers.
Rusting can completely eat away iron. Note the galvanization on the unrusted portions.
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Rusting can completely eat away iron. Note the galvanization on the unrusted portions.
Iron alloy phases

Austenite (γ-iron; hard)
Bainite
Martensite
Cementite (iron carbide; Fe3C)
Ledeburite (ferrite - cementite eutectic, 4.3% carbon)
Ferrite (α-iron, δ-iron; soft)
Pearlite (88% ferrite, 12% cementite)
Spheroidite

Types of Steel

Plain-carbon steel (up to 2.1% carbon)
Stainless steel (alloy with chromium)
HSLA steel (high strength low alloy)
Tool steel (very hard; heat-treated)

Other Iron-based materials

Cast iron (>2.1% carbon)
Wrought iron (almost no carbon)
Ductile iron

Rust is a general term for iron oxides formed by the reaction of iron with oxygen. Several forms of rust are distinguishable visually and by spectroscopy, and form under different circumstances.[1] The chemical composition of rust is typically hydrated iron(III) oxide (Fe2O3.nH2O), and under wet conditions may include iron(III) oxide-hydroxide (FeO(OH)). Rusting is the common term for corrosion of iron and its alloys, such as steel. Although oxidation of other metals is equivalent, these oxides are not commonly called rust.

As rust has higher volume than the originating mass of iron, its buildup may force apart adjacent parts - a phenomenon known as rust smacking.

Chemistry

The rusting of iron is one of the more widely used examples of corrosion. This electrochemical process requires the presence of water, oxygen and an electrolyte and leads to the formation of hydrated iron oxides.

Net reactions

The overall outcome of rust formation involves reaction of iron with varying amounts of oxygen and water.

  • 2Fe + O2 + 2H2O = 2Fe(OH)2
  • 4Fe + O2 + 6H2O = 4Fe(OH)3
  • 4Fe + O2 + 2H2O = 2Fe2O3•H2O
  • 6Fe + 4O2 = 2Fe3O4

Mechanism

Pure, solid iron oxidizes in water:

Fe(s) => Fe2+(aq) + 2e-

These electrons will quickly react with the disassociated hydrogen ions (in H3O+(aq) form) and the dissolved oxygen in the water (O2(aq)):

4e-(aq) + 4H3O+(aq) + O2(aq) -> 6H2O(l)

Therefore, as seen from the above equation, the more acidic the water, the greater will be the rate of corrosion (since the concentration of H3O+(aq) will be greater.) At extremely low pH’s, the hydrogen ions will react with the electrons producing hydrogen gas instead:

2H+(aq) + 2e-(aq) -> H2(g)

Thus, as seen from the above equations, the pH of the solution (whether it is pure water or water containing electrolytes) rises. This leads to the formation of OH- ions (in cases where the body of water is significantly large, the pH does not rise as sharply, but this is of no consequence since OH- ions are always present, even in pure water.) The cations then react with the OH- or even the H+ ions and dissolved oxygen to form a variety of compounds, which constitute rust:

Fe2+(aq) + 2OH-(aq) -> Fe(OH)2(s)

4Fe2+(aq) + 4H+(aq) + O2(aq) -> 4Fe3+(aq) + 2H2O(l)

Fe3+(aq) + 3OH-(aq) -> Fe(OH)3(s)

From the above equations, it is seen that the pH and amount of dissolved oxygen can affect the outcome of the reactions. In water with limited dissolved oxygen Fe3O4(s) is formed, which is a black solid and commonly called lodestone:

6Fe2+(aq) + O2(aq) + 12OH-(aq) -> 2Fe3O4(s) + 6H2O(l)

The porous Fe(OH)3 rust can slowly disintegrate into a crystallized form, which is the familiar red-brown rust:

2Fe(OH)3(s) -> Fe2O3•H2O(s) + 2H2O(l)

Iron oxide (FeO) can also be formed. The presence of other ions, such as calcium or calcium carbonates reacts with the iron hydroxides and iron oxides to form a variety of precipitates. Other metals corrode via similar chemical processes.

Rust prevention

Hydrated rust is permeable to air and water, allowing the metal to continue to corrode - internally - even after a surface layer of rust has formed. Given sufficient hydration, the iron mass can eventually convert entirely to rust and disintegrate. Corrosion of aluminium is different from steel or iron, in that aluminium oxide formed on the surface of aluminum metal forms a protective, corrosion resistant coating, a process known as passivation. Stainless steel similarly resists rusting by forming a passivation layer of chromium(III) oxide. This is also true of magnesium, copper, titanium, and zinc.

Galvanization consists of coating metal with a thin layer of another such metal. Typically, zinc is applied by either hot-dip galvanizing or electroplating. Zinc is traditionally used because it is cheap, easy to refine and adheres well to steel. In more corrosive environments (such as at sea) cadmium may be used. Galvanization often fails at seams, holes and joints, where the coating is pierced. In these cases the coating provides cathodic protection to metal, where it acts as a galvanic anode rusting in preference.

More modern coatings add aluminium to the coating as zinc-alume, aluminium will migrate to cover scratches and thus provide protection for longer. These rely on the aluminium and zinc oxides protecting the once-scratched surface rather than oxidizing as a sacrificial anode.

There are several other methods available to control corrosion and prevent the formation of rust, colloquially termed rustproofing.

  • Cathodic protection makes the iron a cathode in a battery formed whenever water contacts the iron and also a sacrificial anode made from something with a more negative electrode potential, commonly zinc or magnesium. The electrode itself doesn't react in water, but only provides electrons to prevent the iron rusting.
  • Bluing is a technique that can provide limited resistance to rusting for small steel items, such as firearms; for it to be successful, water-displacing oil must be rubbed onto the blued steel.
  • Corrosion control can be done using a coating to isolate the metal from the environment, such as paint. 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. This may contain rust inhibiting chemicals as well as forming a barrier. Covering steel with concrete provides protection to steel by the high pH environment at the steel-concrete interface. However, if concrete covered steel does corrode, the rust formed can cause the concrete to spall and fall apart. This creates structural problems.

To prevent rust corrosion on automobiles, they should be kept cleaned and waxed. The underbody should be sprayed to make sure it is free of dirt and debris that could trap moisture. After a car is washed, it is best to let it sit in the sun for a few hours to let it air dry. In winter, or in salty conditions, cars should be washed more regularly as road salt (calcium chloride) can accelerate the rusting process.

References

  1. ^ Interview, David Des Marais.

See also

Wikimedia Commons has media related to:

External links


 
Translations: Translations for: Rust

Dansk (Danish)
n. - rust, skimmelsvamp
v. intr. - ruste, blive angrebet af skimmelsvamp
v. tr. - gøre rusten

idioms:

  • rust belt    rustbæltet (område i USA med industri i stærk tilbagegang)

Nederlands (Dutch)
roesten, roest, vastroesten

Français (French)
n. - (Agric, Chim, Hort) rouille
v. intr. - (lit) rouiller, (fig) altérer
v. tr. - (lit) se rouiller, (fig) s'altérer

idioms:

  • rust belt    ceinture de rouille (ancienne zone industrielle)

Deutsch (German)
n. - Rost
v. - rosten, einrosten

idioms:

  • rust belt    (ugs.) Gebiet ehemals profitabler Industrien

Ελληνική (Greek)
n. - σκουριά, οξείδωση
v. - σκουριάζω, οξειδώνομαι

idioms:

  • rust belt    η βιομηχανική ζώνη των βορείων Πολιτειών των ΗΠΑ

Italiano (Italian)
arrugginire, ruggine

idioms:

  • rust belt    industrie in decadenza

Português (Portuguese)
n. - ferrugem (m), ócio (m)
v. - enferrujar, enfraquecer

idioms:

  • rust belt    área onde existe muitas riquezas minerais

Русский (Russian)
ржаветь, ржавчина

idioms:

  • rust belt    Средний Запад и северо-восток США

Español (Spanish)
n. - óxido, herrumbre, orín, moho
v. intr. - oxidarse, enmohecerse, entumecerse
v. tr. - oxidar, herrumbrar, entumecer, enmohecer

idioms:

  • rust belt    zona industrial en decadencia

Svenska (Swedish)
n. - rost, slöhet
v. - rosta, fördärva

中文(简体) (Chinese (Simplified))
锈, 生锈, 衰退, 使生锈, 使荒废, 使变迟钝

idioms:

  • rust belt    铁锈地带, 指从前工业繁盛今已衰落的发达国家一些地区

中文(繁體) (Chinese (Traditional))
n. - 鏽, 生鏽
v. intr. - 生鏽, 衰退
v. tr. - 使生鏽, 使荒廢, 使變遲鈍

idioms:

  • rust belt    鐵鏽地帶, 指從前工業繁盛今已衰落的發達國家一些地區

한국어 (Korean)
n. - (금속의)녹, 나쁜 버릇, 적갈색
v. intr. - 녹슬다, 부식하다, 녹빛이 되다
v. tr. - 녹슬게 하다, 부식 시키다, 둔하게 하다

日本語 (Japanese)
n. - 錆び, さび色, さび病
v. - がさびる, 鈍る, 錆付く

idioms:

  • rust belt    不活発な地域

العربيه (Arabic)
‏(الاسم) صدأ (فعل) يصدأ‏

עברית (Hebrew)
n. - ‮חלודה, חוסר פעולה, עצלות, צבע חום-אדמדם, חולשה כתוצאה מחוסר-פעולה‬
v. intr. - ‮גרם לחלודה‬
v. tr. - ‮החליד, קיבל צבע חלודה, איבד מאיכותו או מיעילותו בשל אי-שימוש או אי-פעילות‬


 
 

Did you mean: rust (in botany), rust fungus, rust (comics), Bernhard Rust, Rust (color), Mathias Rust, Rod Rust, Wilhelm Rust, Donald L. Rust, Joel Rust

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