Determination of Electric Current Capacity of Electrode by Means of Fracture with Electric Current (2)

Abstract

Graphite specimens were fractured with an electric current under tensile load for the purpose of determining the electric current capacity of electrodes. Judging from the phemomena attending the fracture, it is presumed that the fracture was caused by sublimation of the specimens.
The following relationship exists between the current density and the fracture time.
i=At^-n
where i is the electric current density and t, the fracture time. n=0.4. The constant A is decided according to the specimen used.
The changes of temperature distribution and thermal stress distribution during the experiment were calculated with an electronic computer. The same relationship was obtained as that between the current density and the fracture time. Judging from the calculated results, it is also presumed that the fracture is caused by sublimation of the specimens.