Tungsten and tungsten copper for electronic & electrical

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. 

Molybdenum and molybdenum copper for electronic & electrical

Molybdenum’s role in the electronics market has been an important one since the earliest days of vacuum tubes. Common electronic applications include components used to manufacture electrical devices, including setter tiles for sintering ceramic substrates and multilayer ceramic circuits, as well as physical-vapor deposition masks. Molybdenum is also used for thermal-management applications when paired with copper and is a necessary part of high-power diodes and rectifiers as well as field-emitter components in flat-panel displays.