Bell metal

The higher tin content increases the rigidity of the metal, and increases the resonance. Historically, it was preferred for early cannons. Today, it also has industrial uses, being specified for valve bodies, piston rings, bearings, and bushings. Tin and copper are relatively soft metals that will deform on striking (though tin to a lesser extent than copper), but alloying the two creates bronze, which is harder and less ductile and also one with more elasticity than either of the two original metals. This metal combination produces a tough, long-wearing material that is resistant to oxidation and subject only to an initial surface weathering. Verdigris forms a protective patina on the surface of bells which coats and protects them against further oxidation. Specifically, it is the combination of low internal damping and low internal sound velocity that makes bell metal specially suitable for resonant percussion instruments. Most commonly, as per its colloquial name, bell metal has been and is used for the casting of high-quality bells.