Tungsten electrode as a hot electron emission material is widely used in argon arc welding, plasma welding, spraying, cutting and other technical fields. Hot electron emission materials shall have the following characteristics:

Strong electron emission capacity, high melting point, low evaporation rate (the operating temperature must be over 2 000K); Excellent mechanical properties at high temperature; Good chemical stability; Abundant raw materials, high processing rate, low cost.

Tungsten has become an important hot electron emission material in industrial applications due to its advantages of low escape work (4.55eV), high melting point (3 410℃), low vapor pressure (8.60×10-10 Pa at 1 700℃), and abundant raw materials.