Phosphor bronze is an alloy of copper with 3.5 to 10% of tin and a significant phosphorus content of up to 1%. The phosphorus is added as deoxidizing agent during melting.
These alloys are notable for their toughness, strength, low coefficient of friction, and fine grain. The phosphorus also improves the fluidity of the molten metal and thereby improves the castability, and improves mechanical properties by cleaning up the grain boundaries.
Phosphor bronze is used for springs, bolts and various other items used in situations where resistance to fatigue, wear and chemical corrosion are required e.g. ship’s propellers in a marine environment. The alloy is also used in some dental bridges. Additionally, it can be found in some electrical circuits due to its low resistance to current.
Grades A, C and E — C51000, 52100, 50700 are commonly used nonferrous spring alloys. The combination of good physical properties, fair electrical conductivity and moderate cost make Phosphor Bronze round, square, flat and special shaped wire desirable for many springs and contacts and a wide variety of wire forms where cost of properties does not prescribe Beryllium Copper