Solder alloys
Solder alloys are metallic materials that are used to connect metal workpieces. This is achieved by melting the alloy and then cooling it down. The choice of specific alloy depends on its melting point, chemical reactivity, mechanical properties, toxicity, and other properties. Hence a wide range of solder alloys exist, and only major ones are listed below. Since early 2000s the use of lead in solder alloys is discouraged by several governmental guidelines in the European Union, Japan and other countries, such as Restriction of Hazardous Substances Directive and Waste Electrical and Electronic Equipment Directive.Solder alloys
Properties
The thermal conductivity of common solders ranges from 30 to 400 W/, and the density from 9.25 to 15.00 g/cm3.
| Material | Thermal conductivity
| Melting point
|
| Sn-37Pb | 50.9 | 183 |
| Sn-0.7Cu | 53 | 227 |
| Sn-2.8Ag-20.0In | 53.5 | 175–186 |
| Sn-2.5Ag-0.8Cu-0.5Sb | 57.26 | 215–217 |
| Pb-5Sn | 63 | 310 |
| Lead | 35.0 | 327.3 |
| Tin | 73.0 | 231.9 |
| Aluminum | 240 | 660.1 |
| Copper | 393–401 | 1083 |
| FR-4 | 1.7 | |
