| abstract |
Disclosed is an improved tungsten cathode material which is used for TIG welding, plasma welding, plasma cutting, electric discharge processing, a discharge lamp and the like. The tungsten cathode material is reduced in the amount of use of thorium that is a radioactive element, and has longer life and higher performance. Specifically disclosed is a tungsten cathode material wherein oxide particles, which contain not less than 50 vol% of oxide of at least one element selected from the group consisting of Sm, Nd, Gd and La in total, are dispersed and the average particle diameter d of the oxide particles satisfies the relation of 0 < d ≤ 2.5 μm. If the volume fraction of the total amount of the oxide particles in the tungsten cathode material is represented by f (vol%), the relation 0.083 ≤ f/I is satisfied when the current I (A) applied to an electrode that is formed from the tungsten cathode material is within the range of 0 < I ≤ 40 A. |