Tin bronze is an alloy composed of copper (Cu) and Tin (Sn). Those with a tin content of 20 percent are known as bell bronze.
Bronze is rarely used as a pure binary alloy, but rather is more often found as an additional component in an alloy. Thus, the material properties can be customized based on the amount of the additive. In wrought alloys phosphorous and zinc are the two most common additives, whereas lead, nickel and iron are more often used in the creation of casting alloys. Such alloys are refered to as multi-component (composition) bronzes.
Because pure copper is realtively soft, bronze, through the addition of Tin, has a greater hardness and tensile strength. Additionally, bronze is very resistant to corrosion and wear, also with the presence of sea water. The electrical and thermal conductivity remains good with a small tin content, even if it is not as optimal as those of pure copper. However as tin content increases, the conductivity decreases as the tensile strength and hardness increases. Bronze also offers good spring and sliding properties and has excellent fatigue strength.
Depending on how they are processed, wrought and casting alloys can be distinguished:
- Wrought alloys are suitable for hot and cold forming by rolling, pressing and drawing technique; in addition to copper they contain up to 8.5 precent tin.
- Casting alloys generally have a tin content between nine and 12 percent.