Abstract: A tungsten cathode material to be used for TIG welding, plasma spraying, plasma cutting, electro-discharge machining, discharge lamps, and the like is improved; use of the radioactive element thorium is reduced; and a long life and a high performance are realized. In a tungsten cathode material, oxide particles containing an oxide or oxides of at least one selected from the group consisting of Sm, Nd, Gd, and La in a total amount of 50 vol % or more are dispersed, the oxide particles having an average particle diameter d satisfying the relationship 0<d?2.5 ?m. Given a volume fraction f (vol %) of the total amount of the oxide particles in the tungsten cathode material, 0.083?f/I holds when a current I(A) such that 0<I?40 A is applied to an electrode being made of the tungsten cathode material.

Abstract: A tungsten cathode material to be used for TIG welding, plasma spraying, plasma cutting, electro-discharge machining, discharge lamps, and the like is improved; use of the radioactive element thorium is reduced; and a long life and a high performance are realized. In a tungsten cathode material, oxide particles containing an oxide or oxides of at least one selected from the group consisting of Sm, Nd, Gd, and La in a total amount of 50 vol % or more are dispersed, the oxide particles having an average particle diameter d satisfying the relationship 0<d?2.5 ?m. Given a volume fraction f (vol %) of the total amount of the oxide particles in the tungsten cathode material, 0.083?f/I holds when a current I(A) such that 0<I?40 A is applied to an electrode being made of the tungsten cathode material.