Physical properties of bronze
Answers
Bronze Properties
Bronze usually is a golden hard, brittle metal. The properties depend on the specific composition of the alloy as well as how it has been processed. Here are some typical characteristics:
Highly ductile.
Bronze exhibits low friction against other metals.
Many bronze alloys display the unusual property of expanding a small amount when solidifying from a liquid into a solid. For sculpture casting, this is desirable, as it helps to fill a mold.
Brittle, but less so than cast iron.
Upon exposure to air, bronze oxidizes, but only on its outer layer. This patina consists of copper oxide, which eventually becomes copper carbonate. The oxide layer protects the interior metal from further corrosion. However, if chlorides are present (as from seawater), copper chlorides form, which can cause "bronze disease" -- a condition in which corrosion works through the metal and destroys it.
Unlike steel, striking bronze against a hard surface won't generate sparks. This makes bronze useful for the metal used around flammable or explosive materials.