To provide higher contact forces in situations where electrical conductivity is not a prime concern, phosphor bronze can be used as a substitute for cartridge brass which is described in the topic "The Brasses."
The bronzes most often used to replace cartridge brass contain 5% and 8% tin, along with a small amount of phosphorous. These alloys are widely available in strip form and in a variety of tempers, which results in a good range of strength and formability. The advantage over cartridge brass in contact force afforded by the phosphor bronzes pervades all tempers. Significant increases in contact force are available with phosphor bronzes. For example, the 5% tin alloy in the half-hard temper is stronger than half-hard cartridge brass, while in the hard temper it is stronger than hard cartridge brass. With innovative design, the cost penalty for alloys carrying a higher price per pound can often be offset by reducing the weight of material required for each contact.
In addition to phosphor bronze there are other higher strength alloys to be considered for higher contact forces. These are considered in the topic "Higher Strength Alloys."