Tin base white metals are used where the bearings are subjected to

Pure metals are soft, tough and ductile with a high coefficient of friction. Intermetallic compounds are hard and wear-resistant but brittle. By themselves, these do not make ideal bearing materials.
The white metals are any of several light-colored alloys used as a base for plated silverware, ornaments or novelties, as well as any of several lead-based or tin-based alloys used for things like bearings, jewellery, miniature figures, fusible plugs, some medals and metal type.