Official Answer
Answer
Phosphor Bronze (typically Alloy C51000) is used primarily for its 'non-sparking' properties. In environments with volatile gases or dust (ATEX zones), a steel ring striking a steel housing during installation or failure could generate a spark and trigger an explosion. Phosphor Bronze is also non-magnetic and provides good corrosion resistance. However, its tensile strength is significantly lower than carbon steel (approx. 90-110 ksi). Engineers must compensate for this by designing wider radial walls or using the material only in 'low-load' positioning applications. Its lower $E$ ($16 imes 10^6$ psi) also means it has less 'grip' on the groove, necessitating careful RPM limit calculations.
