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Brass is an
alloy An alloy is an admixture of metal A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Elec ...
of
copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conductivity, thermal and electrical conductivity. A fres ...

copper
and
zinc Zinc is a chemical element with the Symbol (chemistry), symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-greyish appearance when oxidation is removed. It is the first element in group 12 ele ...

zinc
, in proportions which can be varied to achieve varying mechanical, electrical, and chemical properties. It is a
substitutional alloy An alloy is an admixture of metals, or a metal combined with one or more other Chemical element, elements. For example, combining the metallic elements gold and copper produces red gold, gold and silver becomes white gold, and silver combined ...
: atoms of the two constituents may replace each other within the same crystal structure. Brass is similar to
bronze Bronze is an alloy consisting primarily of copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal con ...
, another alloy containing copper that uses
tin Tin is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers ...

tin
instead of zinc. Both bronze and brass also may include small proportions of a range of other elements including
arsenic Arsenic is a chemical element with the Symbol (chemistry), symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It ...
,
lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate h ...

lead
,
phosphorus Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly Reactivity (chemistry), reactive, phosphor ...

phosphorus
,
aluminum Aluminium (aluminum in American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the United States The United States of America (USA), commonly known as the Unit ...
,
manganese Manganese is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

manganese
, and
silicon Silicon is a chemical element with the Symbol (chemistry), symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a Tetravalence, tetravalent metalloid and semiconductor. It is a member ...

silicon
. Historically, the distinction between the two alloys has been less consistent and clear, and modern practice in museums and
archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. Archaeology is often considered a branch of socio-cultural anthropology, but archaeologists also draw from biological, geological ...
increasingly avoids both terms for historical objects in favor of the more general "
copper alloy Copper alloys are metal alloys that have copper Copper is a chemical element with the Symbol (chemistry), symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductility, ductile metal with very high thermal conduc ...
". Brass has long been a popular material for decoration due to its bright, gold-like appearance; being used for
drawer pull A drawer pull (wire pull or simply pull) is a handle to pull a drawer Image:Drawer.png, Artist's illustration of a drawer box A drawer is a box-shaped container that fits into a piece of furniture in such a way that it can be drawn out horizon ...
s and
doorknobs
doorknobs
. It has also been widely used to make utensils due to properties such as having a low melting point, high workability (both with hand tools and with modern
turning Turning is a machining process in which a cutting tool (machining), cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotation around a fixed axis, rotates. Usually ...

turning
and
milling Milling may refer to: * Milling (grinding), breaking solid materials into smaller pieces by grinding, crushing, or cutting in a mill * Milling (machining), a process of using rotary cutters to remove material from a workpiece * Milling (military tra ...
machines), durability, and
electrical Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon in which an object changes its positio ...
and
thermal conductivity The thermal conductivity of a material is a measure of its ability to heat conduction, conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials ...

thermal conductivity
. Brass is still commonly used in applications where corrosion resistance and low
friction Friction is the force In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), ...

friction
are required, such as
lock Lock may refer to: *Lock and key A lock is a mechanics, mechanical or Electronics, electronic fastening device that is released by a physical object (such as a key, Keycard lock, keycard, fingerprint, Radio-frequency identification, RFID card ...

lock
s,
hinge Image:Hamburgerpaumelle.JPG, A barrel hinge A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other a ...

hinge
s,
gear Cast iron mortise wheel with wooden cogs (powered by an external water wheel) meshing with a cast iron gear wheel, connected to a pulley A pulley is a wheel on an axle or shaft (mechanical engineering), shaft that is designed to support ...

gear
s,
bearing Bearing may refer to: * Bearing (angle), a term for direction * Bearing (mechanical), a component that separates moving parts and takes a load * Bridge bearing, a component separating a bridge pier and deck * Bearing BTS Station in Bangkok See also ...
s,
ammunition Ammunition (informally ammo) is the material fired, scattered, dropped or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weapons ...
casings,
zipper A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding the edges of an opening of fabric A textile is a flexible material made by creating an interlocking network of yarn Yarn is ...

zipper
s,
plumbing Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delive ...

plumbing
,
hose coupling A hose coupling is a connector on the end of a hose to connect (or ''couple'') it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel Steel is an alloy of iron with typically a ...
s,
valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries A slurry composed of glass beads in silicone oil flowing down an inclined plane A slurry is a mixt ...

valve
s, and electrical plugs and sockets. It is used extensively for
musical instruments A musical instrument is a device created or adapted to make musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person who pla ...
such as
horn Horn usually refers to: *Horn (acoustic), a conical or bell shaped aperture used to guide sound ** Horn (instrument), collective name for tube-shaped wind musical instruments *Horn (anatomy), a pointed, bony projection on the head of various anima ...

horn
s and
bell A bell is a struck idiophone, directly struck idiophone percussion instrument. Most bells have the shape of a hollow cup that when struck vibrates in a single strong strike tone, with its sides forming an efficient resonator. The strike may be m ...
s, and also used as a substitute for copper in making
costume jewelry Costume jewelry includes a range of decorative items worn for personal adornment that are manufactured as less expensive ornamentation to complement a particular fashionable outfit or garmentBaker, Lillian. Fifty Years of Collectable Fashion Je ...
,
fashion jewelry
fashion jewelry
, and other imitation jewelry. The composition of brass, generally 66% copper and 34% zinc, makes it a favorable substitute for copper based jewelry, as it exhibits greater resistance to corrosion. Brass is often used in situations in which it is important that sparks not be struck, such as in fittings and tools used near flammable or explosive materials.


Properties

Brass is more malleable than bronze or zinc. The relatively low
melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase exist in Thermodynamic equilibrium, equilibrium. ...

melting point
of brass (, depending on composition) and its flow characteristics make it a relatively easy material to cast. By varying the proportions of copper and zinc, the properties of the brass can be changed, allowing hard and soft brasses. The
density The density (more precisely, the volumetric mass density; also known as specific mass), of a substance is its mass per unit volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter Rho (letter), rho), although the L ...
of brass is . Today, almost 90% of all brass alloys are recycled. Because brass is not
ferromagnetic Ferromagnetism is the basic mechanism by which certain materials (such as iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first tra ...
, it can be separated from ferrous scrap by passing the scrap near a powerful magnet. Brass scrap is collected and transported to the foundry, where it is melted and recast into
billet A billet is a living quarters to which a soldier A soldier is one who fights as part of a military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It ...
s. Billets are heated and extruded into the desired form and size. The general softness of brass means that it can often be machined without the use of
cutting fluidImage:Makino-S33-MachiningCenter-example.jpg, Thin-wall milling of aluminum using a water-based cutting fluid on the milling cutter. Cutting fluid is a type of coolant and lubrication, lubricant designed specifically for metalworking processes, such ...
, though there are exceptions to this. Aluminium makes brass stronger and more corrosion-resistant. Aluminium also causes a highly beneficial hard layer of
aluminium oxide Aluminium oxide is a chemical compound of aluminium Aluminium (aluminum in American English, American and Canadian English) is a chemical element with the Symbol (chemistry), symbol Al and atomic number 13. Aluminium has a dens ...
(Al2O3) to be formed on the surface that is thin, transparent, and self-healing. Tin has a similar effect and finds its use especially in
seawater Seawater, or salt water, is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of E ...

seawater
applications (naval brasses). Combinations of iron, aluminium, silicon, and manganese make brass
wear Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion In earth science, erosion is the action of surface processes (such as Surface runoff, water flow or wind) tha ...

wear
- and tear-resistant. Notably, the addition of as little as 1% iron to a brass alloy will result in an alloy with a noticeable magnetic attraction. Brass will
corrode Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide of rutile. Ti(IV) centers are grey; oxygen centers are red. Notice that oxygen forms three bonds to titanium and titanium forms six bon ...
in the presence of moisture,
chloride The chloride ion is the anion An ion () is a particle, atom or molecule with a net electric charge, electrical charge. The charge of the electron is considered negative by convention. The negative charge of an ion is equal and opposite ...

chloride
s,
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...
s,
ammonia Ammonia is a chemical compound, compound of nitrogen and hydrogen with the chemical formula, formula NH3. A Binary compounds of hydrogen, stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct p ...
, and certain acids. This often happens when the copper reacts with sulfur to form a brown and eventually black surface layer of
copper sulfideCopper sulfides describe a family of chemical compounds and minerals with the formula CuxSy. Both mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Eart ...
which, if regularly exposed to slightly acidic water such as urban rainwater, can then oxidize in air to form a
patina File:Ancienne unité de monnaie en cuivre.jpg, Pre-colonial copper coin formerly used in the Copper Belt (Democratic Republic of the Congo and Zambia). The external layer has been weathered by moisture and rain, leading to the oxidation of copper ...

patina
of green-blue
copper sulfateCopper sulfate may refer to: * Copper(II) sulfate, CuSO4, a common compound used as a fungicide and herbicide * Copper(I) sulfate, Cu2SO4, an unstable compound which is not commonly used {{Short pages monitor