Babbitt metal, also called white metal, a…

Babbitt metal, also called white metal, a low-friction, tin-based alloy used to provide the bearing surface in a plain bearing, is invented in 1839 by Isaac Babbitt in Taunton, Massachusetts, USA.

The term is used today to describe a series of alloys used as a bearing metal.

Babbit metal is characterized by its resistance to galling.

Soft and easily damaged, the alloy seems at first sight an unlikely candidate for a bearing surface, but this appearance is deceptive.

The structure of Babbit metal is made up of small hard crystals dispersed in a matrix of softer alloy.

As the bearing wears the harder crystal is exposed, with the matrix eroding somewhat to provide a path for the lubricant between the high spots that provide the actual bearing surface.

Common compositions for Babbitt alloys include 90% tin 10%, copper; 89% tin, 7% antimony, 4% copper; and 80% lead, 15% antimony, 5% tin.

(Used extensively in engine bearings today, it was originally used as a cast-in-place bulk bearing material but is now more commonly used as a thin surface layer in a complex, multi metal structure.)