White metal
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The white metals are a series of often decorative bright metal
A white metal alloy may include
Silver
In compliance with British law, the British fine art trade uses the term "white metal" in auction catalogues to describe foreign silver items which do not carry British Assay Office hallmarks, but which are nonetheless understood to be silver and are priced accordingly.
Tin-lead and tin-copper alloys
Tin-lead and tin-
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.
Alloys consist of small particles of a hard compound embedded in the tough, ductile background of a solid solution. In service the latter can wear away slightly, leaving the hard compound to carry the load. This wear also provides channels to allow in lubricant (oils). All bearing metals contain antimony (Sb), which forms hard cubic crystals.
| % Sn | % Sb | % Cu | % Pb | Applications |
|---|---|---|---|---|
| 93 | 3.5 | 3.5 | – | Light and medium internal combustion engine big-end bearings |
| 86 | 10.5 | 3.5 | – | Light and medium internal combustion engine main bearings |
| 80 | 11 | 3.0 | 6.0 | General-purpose heavy bearings (lead increases plasticity) |
| 60 | 10 | 28.5 | 1.5 | Heavy-duty marine engine bearings, electrical machines |
| 40 | 10 | 1.5 | 48.5 | Low-cost, general-purpose, medium-duty bearings |
See also
References
- ^ a b "White Metals". Belmont Metals. Retrieved April 18, 2021.
- ^ US patent 1252, Isaac Babbitt, "Mode of making boxes for axles and gudgeons", issued 17 Jul 1839.
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