Arsenical copper

Arsenical copper contains up to 0.5% arsenic which, at elevated temperatures, imparts higher tensile strength and a reduced tendency to scaling. It is typically specified in boiler work, especially locomotive fireboxes.^[1][2][3] It also helps prevent embrittlement of oxygen-free copper by bismuth, antimony and lead by the formation of complex oxides. Copper with a larger percentage of arsenic is called arsenical bronze, which can be work-hardened much harder than copper.

Especially in Egyptian archaeology and ancient Near Eastern archaeology,^[4] arsenical copper is used as a term for the material widely used before the beginning of the New Kingdom, i.e. in the Chalcolithic, Early and Middle Bronze Age, for practical objects, tools, weapons, but also vessels.^[5] This is because the intentionality of the production of alloy was doubted in the earlier literature, even if arsenic was detected in crucibles producing such material.^[6] An industrial-scale production was demonstrated for the Early Bronze Age Iran, at the site of Arisman.^[7] Recent data indicate that also in ancient Egypt, specifically in Middle Kingdom, arsenical bronze was produced intentionally, and the use of the term arsenical bronze is warranted.^[8] Despite these findings, majority of researchers will be still using the term arsenical copper.