Phosphor bronze properties: Which of the following accurately summarises the key engineering advantages of phosphor bronze (Cu–Sn–P)?

Introduction / Context:
Phosphor bronze is a copper–tin alloy with a small phosphorus addition. It is widely used for springs, bearings, electrical contacts, and marine hardware. Knowing its property package helps designers select it over brass, aluminium bronze, or beryllium copper for specific applications.

Given Data / Assumptions:

• Chemistry: copper base with several percent tin and trace phosphorus.
• Applications require wear resistance, corrosion resistance, and formability.
• Elasticity here refers to useful springiness (modulus and yield balance).

Concept / Approach:
Tin in bronze improves strength and corrosion resistance, especially in marine and industrial atmospheres. Phosphorus acts as a deoxidiser during melting and forms fine phosphides that improve wear resistance and fatigue properties. Many grades cold work well, enabling springs and thin-section components with good elastic recovery. Therefore, the most complete statement of its advantages is “all of these.”

Step-by-Step Solution:
Identify contributions: Sn → strength/corrosion; P → deoxidation/wear improvement.Relate to performance: good bearing life, spring behaviour, and formability.Compare to options: each listed property is valid.Select the comprehensive option “all of these”.

Verification / Alternative check:
Materials handbooks cite phosphor bronze for marine springs, bushings, and wear plates owing to the property bundle listed.

Why Other Options Are Wrong:
Choosing any single property underestimates the alloy’s balanced performance.

“None of these” contradicts well-established characteristics.

Common Pitfalls:
Confusing phosphor bronze with brass (Cu–Zn) or aluminium bronze; overlooking that springiness depends on both modulus and yield strength, which are favourable in phosphor bronzes.

Final Answer:
all of these