Application of Fusible Alloys

Molten fusible alloys can be used as coolants because they are stable under heating and have higher thermal conductivity than most other coolants. Especially alloys made from metals with high thermal conductivity such as indium or sodium. Metals with low neutron cross-sections are used to cool nuclear reactors.

Such alloys are used in the manufacture of fusible plugs that are inserted in the roof of steam boilers as a protective measure when the allowable water level is too low. When this happens, the plug, which is no longer covered by water, is heated to melting temperature and allows the contents of the boiler to escape into the furnace. In a sprinkler, the orifice of each sprinkler is closed with a plug of fusible metal fastened to a plug that melts and releases water when the temperature rises above a predetermined limit due to a fire in the room .

Bismuth in cooling expands by about 3.3% by volume. Alloys with at least half the bismuth content also show this behavior. This can be used for the installation of small parts, eg for machining, as they will be held securely.