Pure copper is purple-red, so it is also called copper. It has excellent thermal conductivity and electrical conductivity. Its conductivity is second only to silver and second to metal. Copper has excellent chemical stability and corrosion resistance and is an excellent metal material for electricians.
Copper alloys widely used in the industry include brass, bronze, and white copper.
The alloy of Cu and Zn is called brass, in which Cu accounts for 60% to 90% and Zn accounts for 40% to 10%. It has excellent thermal conductivity and corrosion resistance and can be used as various instrument parts. Another example is the addition of a small amount of Sn in brass, called naval brass, which has good resistance to seawater corrosion. A small amount of lubricated Pb is added to the brass and can be used as a sliding bearing material.
Bronze is the oldest metal material used by humans. It is a Cu and Sn alloy. The addition of tin significantly improves the strength of copper, and improves its plasticity and corrosion resistance. Therefore, tin bronze is commonly used in the manufacture of wear-resistant parts such as gears and corrosion-resistant parts. Sn is relatively expensive, and a large number of bronze alloys have been obtained by using a large amount of Al, Si, and Mn instead of Sn. Aluminum bronze has better corrosion resistance than tin bronze. Beryllium bronze is the strongest copper alloy. It is non-magnetic and has excellent corrosion resistance. It is a spring material that can compete with steel.
White copper is a Cu-Ni alloy with excellent corrosion resistance and high electrical resistance, so it can be used as a material for components and resistors operating under severe corrosive conditions.
Brass contains zinc and a small amount of tin, lead, aluminum, etc.