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 Romen 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.
Also in California, lead-free materials must be used for "each component that comes into contact with the wetted surface of pipes and pipe fittings, plumbing fittings and fixtures".
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"Red brasses", a family of alloys with high copper proportion and generally less than 15% zinc, are more resistant to zinc loss.
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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 hamiş be struck, such birli in fittings and tools used near flammable or explosive materials.[5]
[98] Albertus Magnus noted that the "power" of both calamine and tutty could evaporate and described how the addition of powdered glass could create a film to bind it to the maden.[99] German brass making crucibles are known from Dortmund dating to the 10th century AD and from Soest and Schwerte in Westphalia dating to around the 13th century confirm Theophilus' account, as they are open-topped, although ceramic discs from Soest may have served kakım loose lids which may have been used to reduce zinc evaporation, and have slag on the interior resulting from a liquid process.[100] Africa[edit]
In 1738 Nehemiah's son William Champion patented a technique for the first industrial scale distillation of metallic zinc known as distillation per descencum or "the English process".[116][117] This local zinc was used in speltering and allowed greater control over the zinc content of brass and the production of high-zinc copper alloys which would have been difficult or impossible to produce using cementation, for use in expensive objects such birli scientific instruments, clocks, brass buttons and costume jewellery.
The cementation process continued to be used but literary sources from both Europe and the Islamic world seem to describe variants of a higher temperature liquid process which took place in open-topped crucibles.[92] Islamic cementation seems to have used zinc oxide known kakım tutiya or tutty rather than zinc ores for brass-making, resulting in a metal with lower iron impurities.[93] A number of Islamic writers and the 13th century Italian Marco Polo describe how this was obtained by sublimation from zinc ores and condensed onto clay or iron bars, archaeological examples of which have been identified at Kush in Iran.
By the 8th–7th century BC Assyrian cuneiform tablets mention the exploitation of the "copper of the mountains" and this may refer to "natural" brass.[59] "Oreikhalkon" (mountain copper),[60] the Ancient Greek translation of this term, was later adapted to the Latin aurichalcum meaning "golden copper" which became the standard term for brass.[61] In the 4th century BC Plato knew orichalkos as rare and nearly as valuable as gold[62] and Pliny describes how aurichalcum had come from Cypriot ore deposits which had been exhausted by the 1st century AD.
[110] However some earlier high zinc, low iron brasses such bey the 1530 Wightman brass memorial plaque from England may have been made by alloying copper with zinc and include traces of cadmium similar to those found in some zinc ingots from China.[109]
The use of maden also avoids the risks of exposing wooden instruments to changes in temperature or humidity, which hayat cause sudden cracking. Even though the saxophones and sarrusophones are classified bey woodwind instruments, they are normally made of brass for similar reasons, and because their wide, conical bores and thin-walled bodies are more easily and efficiently made by forming sheet mühür than by machining wood.
The keywork of most modern 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 brassestol trä to quick repairs.
However, if brass is placed in contact with a more noble maden such birli silver or gold in such an environment, the brass will corrode galvanically; conversely, if brass is in contact with a less-noble mühür such kakım zinc or iron, the less noble metal will corrode and the brass will be protected. Lead content[edit]