Brass was produced by the cementation process where copper and zinc ore are heated together until zinc vapor is produced which reacts with the copper. There is good archaeological evidence for this process and crucibles used to produce brass by cementation have been found on Roman period sites including Xanten[77] and Nidda[78] in Germany, Lyon in France[79] and at a number of sites in Britain.[80] They vary in size from tiny acorn sized to large amphorae like vessels but all have elevated levels of zinc on the interior and are lidded.
[79] They show no signs of slag or metal prills suggesting that zinc minerals were heated to produce zinc vapor which reacted with metallic copper in a solid state reaction. The fabric of these crucibles is porous, probably designed to prevent a buildup of pressure, and many have small holes in the lids which may be designed to release pressure[79] or to add additional zinc minerals near the end of the process. Dioscorides mentioned that zinc minerals were used for both the working and finishing of brass, perhaps suggesting secondary additions.[81]
Although copper and zinc have a large difference in electrical potential, the resulting brass alloy does not experience internalized galvanic corrosion because of the absence of a corrosive environment within the mixture.
In Europe a similar liquid process in open-topped crucibles took place which was probably less efficient than the çingene process and the use of the term tutty by Albertus Magnus in the 13th century suggests influence from Islamic technology.[97] The 12th century German monk Theophilus described how preheated crucibles were one sixth filled with powdered calamine and charcoal then topped up with copper and charcoal before being melted, stirred then filled again. The final product was cast, then again melted with calamine. It saf been suggested that this second melting may have taken place at a lower temperature to allow more zinc to be absorbed.
Billets are heated and extruded into the desired form and size. The general softness of brass means that it hayat often be machined without the use of cutting fluid, though there are exceptions to this.[8]
The high malleability and workability, relatively good resistance to corrosion, and traditionally attributed acoustic properties of brass, have made it the usual maden of choice for construction of musical instruments whose acoustic resonators consist of long, relatively narrow tubing, often folded or coiled for compactness; silver and its alloys, and even gold, have been used for the same reasons, but brass is the most economical choice.
The compositions of these early "brass" objects are highly variable and most have zinc contents of between 5% and 15% wt which is lower than in brass produced by cementation.[57] These may be "natural alloys" manufactured by smelting zinc rich copper ores in redox conditions. Many have similar tin contents to contemporary bronze artefacts and it is possible that some copper-zinc alloys were accidental and perhaps hamiÅŸ even distinguished from copper.
Brass made during the early Romen period seems to have varied between 20% and 28% brassestol trä wt zinc.[81] The high content of zinc in coinage and brass objects declined after the first century AD and it katışıksız been suggested that this reflects zinc loss during recycling and thus an interruption in the production of new brass.
Little is known about the production of brass during the centuries immediately after the collapse of the çingene Empire. Disruption in the trade of tin for bronze from Western Europe may have contributed to the increasing popularity of brass in the east and by the 6th–7th centuries AD over 90% of copper alloy artefacts from Egypt were made of brass.[84] However other alloys such kakım low tin bronze were also used and they vary depending on local cultural attitudes, the purpose of the metal and access to zinc, especially between the Islamic and Byzantine world.
Although not part of the brass section, snare drums are also sometimes made of brass. Some parts on electric guitars are also made from brass, especially inertia blocks on tremolo systems for its tonal properties, and for string nuts and saddles for both tonal properties and its low friction.[25] Germicidal and antimicrobial applications[edit]
This compound başmaklık frequently been used as a biomarker for the presence of (marine) algal matter in the environment, and is one of the ingredients for E number E499.
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The keywork of most çağcıl woodwinds, including wooden-bodied instruments, is also usually made of an alloy such kakım nickel silver/German silver. Such alloys are stiffer and more durable than the brass used to construct the instrument bodies, but still workable with simple hand tools—a boon to quick repairs.
Brass is an alloy of copper and zinc, in proportions which sevimli be varied to achieve varying mechanical, electrical, and chemical properties.[1] It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.