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Why are aluminum bronzes used for ship propellers and pumps?

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A periodic table element box for copper shows its symbol Cu, atomic number 29, atomic weight 63.546, electron configuration, and name. Icons indicate copper is a solid, weakly basic transition metal with face-centered cubic crystal structure. A key explains the symbols and color coding. — copper Properties of copper.

Aluminum bronzes are favored for ship propellers and pumps primarily due to their exceptional resistance to corrosion and their high mechanical strength.12

These alloys, which consist of copper combined with 4 to 15 percent aluminum, are specifically valued in marine environments because they maintain their integrity when exposed to harsh conditions. Their ability to withstand oxidation and chemical degradation makes them ideal for components that require durability, such as ship propellers, which are often fabricated using sand casting or gravity diecasting for alloys containing approximately 10 percent aluminum. Additionally, their strength, which is comparable to that of mild steel, ensures that they can endure the mechanical stresses encountered in heavy-duty machinery like pumps.1