Wood's metal, also known as Lipowitz's alloy or by the commercial names Cerrobend, Bendalloy, Pewtalloy and MCP 158, is a metal alloy that is useful for soldering and making custom metal parts, but its vapor is toxic to touch or breathe. The alloy is named for Barnabas Wood, who invented and patented the alloy in 1860.[1][2] It is a eutectic, fusible alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by mass. It has a melting point of approximately 70 °C (158 °F).[3][4]
Other uses include making custom-shaped apertures and blocks (for example, electron-beam cutouts and lung blocks) for medical radiation treatment, and making casts of keys that are hard to otherwise duplicate.[5][6]
Like other fusible alloys, e.g. Rose's metal, Wood's metal can be used as a heat-transfer medium in hot baths. Hot baths with Rose's and Wood's metals are not used routinely but are employed at temperatures above 220 °C (428 °F).[7]
Wood's metal has a modulus of elasticity of 12.7 GPa and a yield strength of 26.2 MPa.[8]
Alloy | Melting point | Eutectic? | Bismuth % |
Lead % |
Tin % |
Indium % |
Cadmium % |
Thallium % |
Gallium % |
Antimony % |
---|---|---|---|---|---|---|---|---|---|---|
Rose's metal | 98 °C (208 °F) | no | 50 | 25 | 25 | – | – | – | – | – |
Cerrosafe | 74 °C (165 °F) | no | 42.5 | 37.7 | 11.3 | – | 8.5 | – | – | – |
Wood's metal | 70 °C (158 °F) | yes | 50 | 26.7 | 13.3 | – | 10 | – | – | – |
Field's metal | 62 °C (144 °F) | yes | 32.5 | – | 16.5 | 51 | – | – | – | – |
Cerrolow 136 | 58 °C (136 °F) | yes | 49 | 18 | 12 | 21 | – | – | – | – |
Cerrolow 117 | 47.2 °C (117 °F) | yes | 44.7 | 22.6 | 8.3 | 19.1 | 5.3 | – | – | – |
Bi-Pb-Sn-Cd-In-Tl | 41.5 °C (107 °F) | yes | 40.3 | 22.2 | 10.7 | 17.7 | 8.1 | 1.1 | – | – |
Gallium | 30.0 °C (86 °F) | Pure metal | - | - | - | - | - | - | 100 | – |
Galinstan | −19 °C (−2 °F) | no | <1.5 | – | 9.5–10.5 | 21–22 | – | – | 68–69 | <1.5 |