2.3  Electrode materials

Figure 2.2 shows that a 10A arc develops a temperature of over 7000K. All electrically conducting material boil at this temperature. Table 1 lists some materials with high melting / boiling points.

 

Figure 2.2: Radial temperature distributions in a cylindrical N2 - arc of 5mm diameter for various currents [Haydon1964]

 
 

melt point / ºC

boiling point / ºC

Conductivity

Graphite (C)

3550

4830

3 · 106 S/m

Tungsten (W)

3410

5657

17.67 · 106 S/m

Tantalum (Ta)

2996

5425

8.1 · 106 S/m

Molybdenum (Mo)

2617

5560

19.20 · 106 S/m

Table 2.1: Electrode Materials

Using these materials minimises the erosion of the electrodes.

Salted water can also be used as electrode material. Depending on the salt, the colour of the arc is determinable [GRIBBEN1996].

 

 

This page is part of a Frameset: Electrodynamic Sculpture: A Thesis by Rafael Bräg.