What composition makes the hardest and toughest type of Babbitt?

The hardest and toughest type of Babbitt is composed of 90% tin combined with either copper or antimony. This specific alloy composition is primarily chosen for its excellent wear resistance and ability to handle high-load conditions effectively. Tin serves as a base metal which, when combined with copper or antimony, enhances the overall mechanical properties of the alloy.

Copper contributes to the hardness and strength of the Babbitt, while antimony improves the alloy's resistance to deformation and wear under load. This combination results in a material that performs exceptionally well in bearing applications, particularly where high speeds and heavy loads are encountered.

In contrast, other options do not provide the same level of performance for Babbitt applications. For instance, 90% lead with copper, although somewhat workable, lacks the hardness and load-bearing capabilities needed for high-performance applications. Similarly, 85% zinc with aluminum, while durable, does not meet the same toughness and longevity standards. Lastly, 100% tin offers excellent corrosion resistance but lacks the added hardness and toughness that alloys with copper or antimony bring to the table.