|Color:||Bronze||Material:||Brass (copper Alloy)|
Ornamental Coffins Screws
Product name:Brass decoration
Application: Tombstone ,cemetery or others.
Manufacturer: Sumer International (Beijing) Trading Co.,Ltd
Size: L 8 cm bird shape
Material: Brass (Copper alloy)
Color /finishing: Antique Bronze
Professionally engaged in funeral field over 10 years;
Customized products acceptable;
Good quality and competitive price;
|Physical properties --- Copper|
|Melting point||1357.77 K (1084.62 °C, 1984.32 °F)|
|Boiling point||2835 K (2562 °C, 4643 °F)|
|Density near r.t.||8.96 g/cm3|
|when liquid, at m.p.||8.02 g/cm3|
|Heat of fusion||13.26 kJ/mol|
|Heat of vaporization||300.4 kJ/mol|
|Molar heat capacity||24.440 J/(mol·K)|
Brass making in the Roman World
During the later part of first millennium BC the use of brass spread across a wide geographical area from Britain and Spain in the west to Iran, and India in the east.This seems to have been encouraged by exports and influence from the Middle East and eastern Mediterranean where deliberate production of brass from metallic copper and zinc ores had been introduced. The 4th century BC writer Theopompus, quoted by Strabo, describes how heating earth from Andeira in Turkey produced "droplets of false silver", probably metallic zinc, which could be used to turn copper into oreichalkos.In the 1st century BC the Greek Dioscorides seems to have recognised a link between zinc mineralsand brass describing how Cadmia (zinc oxide) was found on the walls of furnaces used to heat either zinc ore or copper and explaining that it can then be used to make brass.
By the first century BC brass was available in sufficient supply to use as coinage in Phrygia and Bithynia,and after the Augustan currency reform of 23 BC it was also used to make Roman dupondii and sestertii.The uniform use of brass for coinage and military equipment across the Roman world may indicate a degree of state involvement in the industry,and brass even seems to have been deliberately boycotted by Jewish communities in Palestine because of its association with Roman authority.
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 and Nidda in Germany, Lyonin France and at a number of sites in Britain. 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. They show no signs of slag or metalprills 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 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.
Bird pair Brass decoration BD009
A copper disc (99.95% pure) made by continuous casting; etched to reveal crystallites.
BD008 &BD009 brass decoration
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