Tungsten is practically the only material used for electron emitters. Although other, more electropositive, metals would yield higher emission rates, the advantage of tungsten is its extremely low vapour pressure even at high temperatures.
This property is also important for electrical contact materials. While more conductive metals like copper or silver evaporate (erode) under the conditions of an electric arc, tungsten withstands these.
Tungsten is one of the most important components in modern integrated circuitry and tungsten-copper heat sinks are used to remove the heat of microelectronic devices.