Lead, Tin, and Low Melting Alloys Information
Lead, tin, and low melting alloys are non-ferrous alloys that are easily meltable with relatively low melting temperatures. They are used in the manufacture of solders, semiconductors, batteries, optical, and decorative products. Low melting alloys include bismuth, indium, lead, and tin metals and alloys.
Bismuth is a low melting point metal used as a substitute for lead in solders. Bismuth has a unique property in common with water; liquid bismuth (10.0 g/cc) is denser than solid bismuth (9.78 g/cc). Pure bismuth metal is the most naturally diamagnetic of all elemental metals. Bismuth has a lower thermal conductivity compared to all metals except mercury. Bismuth tellurides are excellent thermoelectric materials and are finding use in CPU coolers.
Indium is used to form several low melting alloys and solders. Indium based solders can "cold weld" because indium tends to be more oxide free, so heat and chemicals are not typically required compared to conventional solders. Indium based solder also reduces gold scavenging - extraction of gold from metal electronic contacts. Indium is also a constituent of Indalloy® (a registered trademark of Indium Corporation) Gallinstan® (a registered trademark of Geratherm Medical AG), Ga-In-Sn alloys, and mercury substitutes, which are liquids at room temperature. Indium is used to manufacture fusible alloys that melt at a specific temperature range
Lead is a metal with a low melting point, a high density, and low hardness. It has a bluish-white color when cut, but tarnishes to a dull gray after exposure to air. It has poor electrical conductivity, is highly resistant to corrosion, and is very malleable. Lead is poisonous at certain levels. It can be toughened by the addition of a small amount of antimony. Lead and lead alloys are used in balancing weights, radiation shielding, battery electrodes, and solders.
Tin is a silvery, malleable metal with a low melting point and low hardness. Tin and tin alloys are used in coatings and platings, as alloying additives, in battery electrodes, and as solders.
Other low melting alloys include antimony and cadmium.
Selecting metals and metal alloys requires an analysis of the desired specifications. Dimensions to consider include:
- Outer diameter (OD)
- Inner diameter (ID)
- Overall length
- Overall thickness
Other specifications of importance (based on application) include product shape, tensile strength, yield strength, melting point, conductivity, corrosion resistance, ductility, and malleability. These properties differ based on the material or alloy composition.
Low melting metal alloys are used as a constituent in fusible alloys for use in fuses, thermostats, switches, barometers, thermal management products, tube bending, lens blocking, potting molds, wax pattern dies and punch anchoring, fire suppression water sprinklers, and workpiece holding.