White metal 432143 217301525 2008-06-05T13:18:15Z Wizard191 935746 added otheruses template {{otheruses4|metals|the music genre|Christian metal}} The '''white metals''' are any of several light-colored [[alloy]]s used as a base for plated [[silverware]], ornaments or novelties, as well as any of several [[lead]]-base or [[tin]]-base alloys used for things like [[Bearing (mechanical)|bearing]]s, [[jewellery]], [[miniature figure]]s, [[fusible plug]]s, some [[medal]]s and metal [[typesetting|type]]. Some of the [[metal]]s that make up a white metal alloy are [[antimony]], [[tin]], [[lead]], [[cadmium]], [[bismuth]], and [[zinc]]. Not all of these metals are found in all white metal alloys but are mixed to achieve a desired goal or need. An example would be for jewelry. You would need it to be [[casting|castable]], [[polishing|polishable]], have good flow characteristics, have the ability to cast fine detail without an excessive amount of [[porosity]] and cast at between 230 °[[Celsius|C]] and 300 °C (450 °[[Fahrenheit|F]] and 575 °F). It should be noted that 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 [[Assay_office#UK_assay_offices|British Assay Office]] marks, but which are nonetheless understood to be silver and are priced accordingly. ==Tin-lead and tin-copper alloys== Tin-lead & tin-[[copper]] alloys have a low melting point that is ideal for use as [[solder]], but these alloys also have ideal characteristics for [[plain bearing]]s. Most importantly for bearings, the material should be hard and wear resistant and have a low coefficient of friction. It must also be shock resistant, tough and sufficiently ductile to allow for slight misalignment prior to running in. 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]] ([[oil]]s). All bearing metals contain [[antimony]] (Sb) which forms hard cubic crystals. {| class="wikitable" style="text-align:center;" |- ! % Sn ! % Sb ! % Cu ! % Pb ! Applications |- | 93 || 3.5 || 3.5 || - || Light and medium IC engine big end bearings |- | 86 || 10.5 || 3.5 || - || Light and medium IC engine main bearings |- | 80 || 11 || 3.0 || 6 || 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== * [[Babbitt metal]] * [[Britannia metal]] * [[Pewter]] * [[Pot metal]] * [[Punchcutting]] * [[ZAMAK]] ==External links== *[http://www.nomastedio.com/Tienda/toy_soldiers_shop.html Miniatures en métal, soldats & miniatures de plomb, objets de collections] [[Category:Alloys]] [[Category:Bearings]] [[de: Weißmetall]]