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Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an
electrochemical Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typi ...
process in which one
metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...
corrodes preferentially when it is in electrical contact with another, different metal, when both in the presence of an
electrolyte An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...
. A similar galvanic reaction is exploited in single-use battery cells to generate a useful electrical voltage to power portable devices. This phenomenon is named after Italian physician
Luigi Galvani Luigi Galvani ( , , ; ; 9 September 1737 – 4 December 1798) was an Italian physician, physicist, biologist and philosopher who studied animal electricity. In 1780, using a frog, he discovered that the muscles of dead frogs' legs twitched when ...
(1737–1798). A similar type of corrosion caused by the presence of an external
electric current An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge c ...
is called ''
electrolytic corrosion Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, different metal, when both in the presen ...
''.


Overview

Dissimilar metals and alloys have different
electrode potential An electrode is an electrical conductor used to make contact with a nonmetallic part of a Electronic circuit, circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can c ...
s, and when two or more come into contact in an electrolyte, one metal (that is more
reactive Reactive may refer to: *Generally, capable of having a reaction (disambiguation) *An adjective abbreviation denoting a bowling ball coverstock made of reactive resin *Reactivity (chemistry) *Reactive mind *Reactive programming See also *Reactanc ...
) acts as
anode An anode usually is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, which is usually an electrode of the device through which conventional current leaves the devic ...
and the other (that is less
reactive Reactive may refer to: *Generally, capable of having a reaction (disambiguation) *An adjective abbreviation denoting a bowling ball coverstock made of reactive resin *Reactivity (chemistry) *Reactive mind *Reactive programming See also *Reactanc ...
) as
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device such as a lead-acid battery. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. Conventional curren ...
. The electropotential difference between the reactions at the two electrodes is the driving force for an accelerated attack on the anode metal, which dissolves into the electrolyte. This leads to the metal at the anode corroding more quickly than it otherwise would and corrosion at the cathode being inhibited. The presence of an electrolyte and an electrical conducting path between the metals is essential for galvanic corrosion to occur. The electrolyte provides a means for
ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
migration Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
whereby ions move to prevent charge build-up that would otherwise stop the reaction. If the electrolyte contains only metal ions that are not easily reduced (such as Na+, Ca2+, K+, Mg2+, or Zn2+), the cathode reaction is the reduction of dissolved H+ to H2 or O2 to OH. Goodisman notes that many chemistry textbooks use an incorrect model for a cell with zinc and copper electrodes in an acidic electrolyte. In some cases, this type of reaction is intentionally encouraged. For example, low-cost household batteries typically contain carbon-zinc cells. As part of a
closed circuit Closed circuit can refer to: *Closed-circuit television *Closed-circuit radio *Closed circuit breathing apparatus, commonly known as rebreathers for portable units, and as component parts of life-support systems for more complex equipment. * ''Clo ...
(the electron pathway), the zinc within the cell will corrode preferentially (the ion pathway) as an essential part of the battery producing electricity. Another example is the
cathodic protection Cathodic protection (CP; ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded " sacrifi ...
of buried or submerged structures as well as
hot water storage tank A hot water storage tank (also called a hot water tank, thermal storage tank, hot water thermal storage unit, heat storage tank, hot water cylinder, and geyser) is a water tank used for storing hot water for space heating or domestic use. Water ...
s. In this case, sacrificial anodes work as part of a galvanic couple, promoting corrosion of the anode, while protecting the cathode metal. In other cases, such as mixed metals in piping (for example, copper, cast iron and other cast metals), galvanic corrosion will contribute to accelerated corrosion of parts of the system.
Corrosion inhibitor 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. The effectiveness of a corrosion inhibitor depends on fluid composition and ...
s such as
sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula . It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite sa ...
or
sodium molybdate Sodium molybdate, Na2MoO4, is useful as a source of molybdenum. This white, crystalline salt is often encountered as the dihydrate, Na2MoO4·2H2O. Preparation Dissolution of MoO3 in sodium hydroxide at 50–70 °C followed by crystallizing t ...
can be injected into these systems to reduce the galvanic potential. However, the application of these corrosion inhibitors must be monitored closely. If the application of corrosion inhibitors increases the conductivity of the water within the system, the galvanic corrosion potential can be greatly increased. Acidity or alkalinity ( pH) is also a major consideration with regard to closed loop bimetallic circulating systems. Should the pH and corrosion inhibition doses be incorrect, galvanic corrosion will be accelerated. In most
HVAC Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. ...
systems, the use of sacrificial anodes and cathodes is not an option, as they would need to be applied within the plumbing of the system and, over time, would corrode and release particles that could cause potential mechanical damage to circulating pumps, heat exchangers, etc.


Examples

A common example of galvanic corrosion occurs in
galvanized iron Galvanization ( also spelled galvanisation) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are coated by submerging them in a bath of ...
, a sheet of iron or steel covered with a zinc coating. Even when the protective
zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
coating is broken, the underlying
steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...
is not attacked. Instead, the zinc is corroded because it is less "noble". Only after it has been consumed can rusting of the base metal occur. By contrast, with a conventional
tin can A steel can, tin can, tin (especially in British English, Australian English, Canadian English and South African English), or can is a container made of thin metal, for distribution or storage of goods. Some cans are opened by removing the to ...
, the opposite of a protective effect occurs: because the
tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...
is more noble than the underlying steel, when the tin coating is broken, the steel beneath is immediately attacked preferentially.


Statue of Liberty

A spectacular example of galvanic corrosion occurred in the
Statue of Liberty The Statue of Liberty (''Liberty Enlightening the World''; ) is a colossal neoclassical sculpture on Liberty Island in New York Harbor, within New York City. The copper-clad statue, a gift to the United States from the people of French Thir ...
when regular maintenance checks in the 1980s revealed that corrosion had taken place between the outer
copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
skin and the
wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.05%) in contrast to that of cast iron (2.1% to 4.5%), or 0.25 for low carbon "mild" steel. Wrought iron is manufactured by heating and melting high carbon cast iron in an ...
support structure. Although the problem had been anticipated when the structure was built by
Gustave Eiffel Alexandre Gustave Eiffel ( , ; Bonickhausen dit Eiffel; 15 December 1832 – 27 December 1923) was a French civil engineer. A graduate of École Centrale des Arts et Manufactures, he made his name with various bridges for the French railway net ...
to
Frédéric Bartholdi Frédéric and Frédérick are the French versions of the common male given name Frederick. They may refer to: In artistry: * Frédéric Back, Canadian award-winning animator * Frédéric Bartholdi, French sculptor * Frédéric Bazille, Impr ...
's design in the 1880s, the insulation layer of
shellac Shellac () is a resin secreted by the female Kerria lacca, lac bug on trees in the forests of India and Thailand. Chemically, it is mainly composed of aleuritic acid, jalaric acid, shellolic acid, and other natural waxes. It is processed and s ...
between the two metals had failed over time and resulted in rusting of the iron supports. An extensive renovation was carried out with replacement of the original insulation with
PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off fro ...
. The structure was far from unsafe owing to the large number of unaffected connections, but it was regarded as a precautionary measure to preserve a national symbol of the United States.


Royal Navy and HMS ''Alarm''

In 1681,
Samuel Pepys Samuel Pepys ( ; 23 February 1633 – 26 May 1703) was an English writer and Tories (British political party), Tory politician. He served as an official in the Navy Board and Member of Parliament (England), Member of Parliament, but is most r ...
(then serving as
Admiralty Admiralty most often refers to: *Admiralty, Hong Kong * Admiralty (United Kingdom), military department in command of the Royal Navy from 1707 to 1964 *The rank of admiral *Admiralty law Admiralty can also refer to: Buildings * Admiralty, Tra ...
Secretary) agreed to the removal of lead sheathing from English
Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
vessels to prevent the mysterious disintegration of their rudder-irons and bolt-heads, though he confessed himself baffled as to the reason the lead caused the corrosion. The problem recurred when vessels were sheathed in copper to reduce marine weed accumulation and protect against
shipworm The shipworms, also called teredo worms or simply teredo (, via Latin ), are marine bivalve molluscs in the family Teredinidae, a group of saltwater clams with long, soft, naked bodies. They are notorious for boring into (and commonly eventual ...
. In an experiment, the Royal Navy in 1761 had tried fitting the hull of the frigate HMS ''Alarm'' with 12-ounce copper plating. Upon her return from a voyage to the West Indies, it was found that although the copper remained in fine condition and had indeed deterred shipworm, it had also become detached from the wooden hull in many places because the iron nails used during its installation "were found dissolved into a kind of rusty Paste". To the surprise of the inspection teams, however, some of the iron nails were virtually undamaged. Closer inspection revealed that water-resistant brown paper trapped under the nail head had inadvertently protected some of the nails: "Where this covering was perfect, the Iron was preserved from Injury". The copper sheathing had been delivered to the dockyard wrapped in the paper which was not always removed before the sheets were nailed to the hull. The conclusion therefore reported to the Admiralty in 1763 was that iron should not be allowed direct contact with copper in sea water.


US Navy littoral combat ship ''Independence''

Serious galvanic corrosion has been reported on the latest US Navy attack littoral combat vessel the USS ''Independence'' caused by steel water jet propulsion systems attached to an aluminium hull. Without electrical isolation between the steel and aluminium, the aluminium hull acts as an anode to the stainless steel, resulting in aggressive galvanic corrosion.


Corroding lighting fixtures

The unexpected fall in 2011 of a heavy light fixture from the ceiling of the
Big Dig The Big Dig was a megaproject in Boston that rerouted the then elevated Central Artery of Interstate 93 that cut across Boston into the O'Neill Tunnel and built the Ted Williams Tunnel to extend Massachusetts Turnpike, Interstate 90 to Logan I ...
vehicular tunnel in
Boston Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeas ...
revealed that corrosion had weakened its support. Improper use of aluminium in contact with stainless steel had caused rapid corrosion in the presence of salt water. The electrochemical
potential difference Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge ...
between stainless steel and aluminium is in the range of 0.5 to 1.0V, depending on the exact alloys involved, and can cause considerable corrosion within months under unfavorable conditions. Thousands of failing lights would have to be replaced, at an estimated cost of $54 million.


Lasagna cell

A "
lasagna Lasagna (, ; ), also known by the plural form lasagne (), is a type of pasta Pasta (, ; ) is a type of food typically made from an Leavening agent, unleavened dough of wheat flour mixed with water or Eggs as food, eggs, and formed in ...
cell" is accidentally produced when salty moist food such as lasagna or sauerkraut is stored in a steel baking pan and is covered with aluminium foil. After a few hours the foil develops small holes where it touches the lasagna, and the food surface becomes covered with small spots composed of corroded aluminium. In this example, the salty food (lasagna) is the electrolyte, the aluminium foil is the anode, and the steel pan is the cathode. If the aluminium foil touches the electrolyte only in small areas, the galvanic corrosion is concentrated, and corrosion can occur fairly rapidly. If the aluminium foil was not used with a dissimilar metal container, the reaction was probably a chemical one. It is possible for heavy concentrations of salt, vinegar or some other acidic compounds to cause the foil to disintegrate. The product of either of these reactions is an
aluminium salt Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity ...
. It does not harm the food, but any deposit may impart an undesired flavor and color.


Electrolytic cleaning

The common technique of cleaning
silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...
ware by immersion in a hot electrolytic bath with a piece of aluminium is an example of galvanic corrosion. Aluminium foil is preferred because of its much greater surface area than that of ingots, although if the foil has a "non-stick" face, this must be removed with steel wool first. The electrolytic bath is usually composed of water and
sodium bicarbonate Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cat ...
, i.e., household baking soda. Silver darkens and corrodes in the presence of airborne sulfur molecules, and the copper in sterling silver corrodes under a variety of conditions. These layers of corrosion can be largely removed through the electrochemical reduction of silver sulfide molecules: the presence of aluminium (which is less noble than either silver or copper) in the bath of sodium bicarbonate strips the sulfur atoms off the silver sulfide and transfers them onto and thereby corrodes the piece of aluminium (a much more reactive metal), leaving elemental silver behind. No silver is lost in the process.


Prevention

There are several ways of reducing and preventing this form of corrosion: * Electrically insulate the two metals from each other. If they are not in electrical contact, no galvanic coupling will occur. This can be achieved by using non-conductive materials between metals of different electropotential. Piping can be isolated with a spool of pipe made of plastic materials, or made of metal material internally coated or lined. It is important that the spool be a sufficient length to be effective. For reasons of safety, this should not be attempted where an electrical earthing system uses the pipework for its
ground Ground may refer to: Geology * Land, the solid terrestrial surface of the Earth * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical circ ...
or has equipotential bonding. * Metal boats connected to a shore line electrical power feed will normally have to have the hull connected to earth for safety reasons. However the end of that earth connection is likely to be a
copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
rod buried within the marina, resulting in a steel-copper "battery" of about 0.5 V. Additionally, the hull of each boat is connected to the hull of all other boats, resulting in further "batteries" between propellers (which may be made of bronze) and steel hulls, which may cause corrosion of the expensive propellers. For such cases, the use of a galvanic isolator is essential, typically two
semiconductor diode A diode is a two- terminal electronic component that conducts electric current primarily in one direction (asymmetric conductance). It has low (ideally zero) resistance in one direction and high (ideally infinite) resistance in the other. A ...
s in series, in parallel with two diodes conducting in the opposite direction (antiparallel). This device is inserted in the protective earth connection between the hull and the shoreline protective conductor. This prevents any current in the protective conductor while the applied voltage is ''less'' than 1.4 V (i.e. 0.7 V per diode), but allows a full current in the case of an electrical fault. There will still be a very minor leakage of current through the diodes, which may result in slightly faster corrosion than normal. * Ensure there is no contact with an electrolyte. This can be done by using water-repellent compounds such as greases, or by coating the metals with an impermeable protective layer, such as a suitable paint, varnish, or plastic. If it is not possible to coat both, the coating should be applied to the more noble, the material with higher potential. This is advisable because if the coating is applied only on the more active material, in case of damage to the coating there will be a large cathode area and a very small anode area, and for the exposed anodic area the corrosion rate will be correspondingly high. * Using antioxidant paste is beneficial for preventing corrosion between copper and aluminium electrical connections. The paste consists of a lower nobility metal than aluminium or copper. * Choose metals that have similar electropotentials. The more closely matched the individual potentials, the smaller the
potential difference Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge ...
and hence the smaller the galvanic current. Using the same metal for all construction is the easiest way of matching potentials. *
Electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...
or other plating can also help. This tends to use more
noble metal A noble metal is ordinarily regarded as a metallic chemical element, element that is generally resistant to corrosion and is usually found in nature in its native element, raw form. Gold, platinum, and the other platinum group metals (ruthenium ...
s that resist corrosion better. Chrome,
nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
, silver and
gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...
can all be used.
Galvanizing Galvanization ( also spelled galvanisation) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are coated by submerging them in a bath of ...
with
zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
protects the steel base metal by sacrificial anodic action. *
Cathodic protection Cathodic protection (CP; ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded " sacrifi ...
uses one or more
sacrificial anode A galvanic anode, or sacrificial anode, is the main component of a galvanic cathodic protection system used to protect buried or submerged metal structures from corrosion. They are made from a metal alloy with a more "active" voltage (more n ...
s made of a metal which is more active than the protected metal. Alloys of metals commonly used for sacrificial anodes include zinc,
magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
, and
aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
. This approach is commonplace in water heaters and many buried or immersed metallic structures. * Cathodic protection can also be applied by connecting a
direct current Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...
(DC) electrical
power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, electric current, current, and frequency to power ...
to oppose the corrosive galvanic current. (See .)


Galvanic series

All metals can be classified into a
galvanic series The galvanic series (or electropotential series) determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experien ...
representing the electrical potential they develop in a given electrolyte against a standard reference electrode. The relative position of two metals on such a series gives a good indication of which metal is more likely to corrode more quickly. However, other factors such as
water aeration Water aeration is the process of increasing or maintaining the oxygen saturation of water in both natural and artificial environments. Aeration techniques are commonly used in pond, lake, and reservoir management to address low oxygen levels or a ...
and flow rate can influence the rate of the process markedly.


Anodic index

The compatibility of two different metals may be predicted by consideration of their anodic index. This parameter is a measure of the electrochemical voltage that will be developed between the metal and gold. To find the relative voltage of a pair of metals it is only required to subtract their anodic indices.Wheeler, Gerson J., The design of electronic equipment: a manual for production and manufacturing, Prentice-Hall, 1972 To reduce galvanic corrosion for metals stored in normal environments such as storage in warehouses or non-temperature and humidity controlled environments, there should not be more than 0.25V difference in the anodic index of the two metals in contact. For controlled environments in which temperature and humidity are controlled, 0.50V can be tolerated. For harsh environments such as outdoors, high humidity, and salty environments, there should be not more than 0.15V difference in the anodic index. For example: gold and silver have a difference of 0.15V, therefore the two metals will not experience significant corrosion even in a harsh environment. When design considerations require that dissimilar metals come in contact, the difference in anodic index is often managed by finishes and plating. The finishing and plating selected allow the dissimilar materials to be in contact, while protecting the more base materials from corrosion by the more noble. It will always be the metal with the most negative anodic index which will ultimately suffer from corrosion when galvanic incompatibility is in play. This is why sterling silver and stainless steel tableware should never be placed together in a dishwasher at the same time, as the steel items will likely experience corrosion by the end of the cycle (soap and water having served as the chemical electrolyte, and heat having accelerated the process).


Electrolytic corrosion

The term "electrolytic corrosion" is most frequently used to indicate corrosion caused by electric current applied to the metal from external sources. The mechanism of this corrosion is essentially the same as for the galvanic corrosion.


See also

*
Corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
*
Galvanic anode A galvanic anode, or sacrificial anode, is the main component of a galvanic cathodic protection system used to protect buried or submerged metal structures from corrosion. They are made from a metal alloy with a more "active" voltage (more n ...
*
Galvanic isolation Galvanic isolation is a principle of isolating functional sections of electrical systems to prevent current flow; no direct conduction path is permitted. Energy or information can still be exchanged between the sections by other means, suc ...
in electrical/electronic circuits *
Galvanic series The galvanic series (or electropotential series) determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experien ...
*
Galvanization Galvanization ( also spelled galvanisation) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are coated by submerging them in a bath of ...
*


References


Sources

*


External links

{{Authority control Corrosion