Aluminium bronze is a type of

bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

in which

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 ...

is the main

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

ing

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 ...

added to

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 ...

(for alloys with aluminum as the major component, see aluminum copper alloy), in contrast to standard bronze (copper and

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 ...

) or

brass Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally copper and zinc. I ...

(copper and

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 ...

). A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper; other alloying agents such as

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

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 ...

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

, and

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

are also sometimes added to aluminium bronzes.

Compositions

The following table lists the most common standard aluminium bronze wrought alloy compositions, by ISO 428 designations. The percentages show the proportional composition of the alloy by weight. Copper is the remainder by weight and is not listed:

Material properties

Aluminium bronzes are most valued for their higher strength and

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 ...

resistance as compared to other bronze alloys. These alloys are

tarnish Tarnish is a thin layer of corrosion that forms over copper, brass, aluminum, magnesium, neodymium and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in ...

-resistant and show low rates of corrosion in

atmospheric An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere ...

conditions, low

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

rates at high temperatures, and low reactivity with

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

ous compounds and other

exhaust Exhaust, exhaustive, or exhaustion may refer to: Law * Exhaustion of intellectual property rights, limits to intellectual property rights in patent and copyright law ** Exhaustion doctrine, in patent law ** Exhaustion doctrine under U.S. law, i ...

products of

combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...

. They are also resistant to corrosion in

sea water Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximate ...

. Aluminium bronzes' resistance to corrosion results from the aluminium in the alloys, which reacts with atmospheric

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

to form a thin, tough surface layer of

alumina Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly ...

(aluminium oxide) which acts as a barrier to corrosion of the copper-rich alloy. The addition of

can improve corrosion resistance. Another notable property of aluminium bronzes are their biostatic effects. The copper component of the alloy prevents colonization by marine organisms including

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

barnacle Barnacles are arthropods of the subclass (taxonomy), subclass Cirripedia in the subphylum Crustacean, Crustacea. They are related to crabs and lobsters, with similar Nauplius (larva), nauplius larvae. Barnacles are exclusively marine invertebra ...

s, and

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

s, and therefore can be preferable to

stainless steel Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...

or other non-cupric alloys in applications where such colonization would be unwanted. Aluminium bronzes tend to have a golden color.

Applications

Aluminium bronzes are most commonly used in applications where their resistance to corrosion makes them preferable to other engineering materials. These applications include

plain bearing file:NYC 100-driving-axle-friction-bearing.jpg, Plain bearing on a 1906 S-Motor locomotive showing the axle, bearing, oil supply and oiling pad file:Linear-table with detail numbered.png, A sliding table with four cylindrical bearings file:GWR Spo ...

s and

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...

components on

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

, guitar strings, valve components,

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...

components (especially for seagoing ships), underwater fastenings in

naval architecture Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and op ...

, and ship

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

s. Aluminium bronze is also used to fulfil the ATEX directive for Zones 1, 2, 21, and 22. The attractive gold-toned coloration of aluminium bronzes has also led to their use in

jewellery Jewellery (or jewelry in American English) consists of decorative items worn for personal adornment such as brooches, ring (jewellery), rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the ...

. Aluminium bronzes are in the highest demand from the following industries and areas: *General sea water-related service *

Water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Th ...

* Oil and

petrochemical Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable s ...

industries (''i.e.'' tools for use in non-sparking environments) *Specialised anti-corrosive applications *Certain structural retrofit building applications Aluminium bronze can be welded using the MIG welding technique with an aluminium bronze core and pure

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

gas. Aluminium bronze is used to replace gold for the casting of dental crowns. The alloys used are chemically inert and have the appearance of gold. The Doehler Die Casting Co. of Toledo, Ohio were known for the production of Brastil, a high tensile corrosion resistant bronze alloy. Italy pioneered the use for coinage of an aluminium-bronze alloy called bronzital (literally "Italian bronze") in its 5- and 10-centesimi from 1939. Its alloy was finalized in 1967 to 92% copper, 6% aluminium, and 2% nickel, and was since used in the 20, 200 and 500

Italian Lira The lira ( , ; : lire, , ) was the currency of Italy between 1861 and 2002. It was introduced by the Kingdom of Italy (Napoleonic), Napoleonic Kingdom of Italy in 1807 at par with the French franc, and was subsequently adopted by the different s ...

coins until 2001. Bronzital has since been used for the

Australian Australian(s) may refer to: Australia * Australia, a country * Australians, citizens of the Commonwealth of Australia ** European Australians ** Anglo-Celtic Australians, Australians descended principally from British colonists ** Aboriginal Aus ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

1- and 2-dollar coins, the pre-2009 Mexican 20- and 50-centavo coins, the inner cores of the bi-metallic Mexican 1-, 2- and 5-peso coins, the pre-2017 Philippine 10-peso coin, the Canadian 2 dollar coin (a.k.a. the 'toonie'), and the outer rings of the Mexican 10-, 20-, 50- and 100-peso coins. Nordic Gold, composed of 89% copper, 5% aluminium, 5% zinc, and 1% tin, is a more recently developed aluminium-bronze alloy for coinage. It was first used for the Swedish 10-kronor coin in 1991, and became widespread after the introduction of Nordic gold 10, 20 and 50-cent

Euro coins There are eight euro coin denominations, ranging from one cent to two euro (the euro is divided into a hundred cents). The coins first came into use in 2002. They have a common Obverse and reverse, reverse, portraying a map of Europe, but each cou ...

in 2002. Aluminium bronze is used in marine applications due to its excellent corrosion resistance in seawater. It is found in marine hardware like

propellers A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

, pumps, and valves, as well as in shipbuilding components and hull fittings. For its non-magnetic properties, it is also used in naval vessels, particularly in

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

equipment.

References

External links

* *Copper Development Association
"Publication Number 80: Aluminium Bronze Alloys Corrosion Resistance Guide", PDF
. Retrieved April 9, 2014. *Copper Development Association
"Publication Number 82: Aluminium Bronze Alloys Technical Data"
Retrieved April 9, 2014 {{Authority control Bronze Copper alloys Aluminium–copper alloys