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 metalloids (such as arsenic or silicon). These additions produce a range of alloys some of which are harder than copper alone or have other useful properties, such as strength, ductility, or machinability. The archaeological period during which bronze was the hardest metal in widespread use is known as the Bronze Age. The beginning of the Bronze Age in western Eurasia is conventionally dated to the mid-4th millennium BCE and early 2nd millennium BCE in China; elsewhere, it gradually spread across regions. The Bronze Age was followed by the Iron Age, which started in about 1300 BCE and reached most of Eurasia by about 500 BCE, although bronze continued to be much more widely used than it is in modern times. Because historical artworks were often made of bronzes (alloyed with tin) and brasses (alloyed with zinc), and old documentation sometimes confused the two terms, modern museum and scholarly descriptions of older artworks increasingly use the generalized term "copper alloy" instead of the names of individual alloys. This is done (at least in part) to prevent database searches from failing merely because of errors or disagreements in the naming of historic copper alloys.