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: Provided is an electrode (1) which has a double structure including Cu or a Cu alloy as an electrode body (2) and a core material (3) made of W, Mo, a W-based alloy, or a Mo-based alloy embedded in a surface of the electrode body (2) which is abutted against a material to be welded, the core material (3) being formed by using W, Mo, the W-based alloy, or the Mo-based alloy which is in the form of a fibrous structure extended by sintering, swaging, and annealing in an electrode axis direction, the fibrous structure having a horizontal cross-sectional average particle diameter of 50 ?m or more and an aspect ratio of 1.5 or more. The electrode (1) can be used as an inexpensive electrode obtained by suppressing particle dropping/attrition and defects in electrodes for spot welding, in which heat and pressure are applied repeatedly, stably enhancing durability.

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: Provided is an electrode (1) which has a double structure including Cu or a Cu alloy as an electrode body (2) and a core material (3) made of W, Mo, a W-based alloy, or a Mo-based alloy embedded in a surface of the electrode body (2) which is abutted against a material to be welded, the core material (3) being formed by using W, Mo, the W-based alloy, or the Mo-based alloy which is in the form of a fibrous structure extended by sintering, swaging, and annealing in an electrode axis direction, the fibrous structure having a horizontal cross-sectional average particle diameter of 50 ?m or more and an aspect ratio of 1.5 or more. The electrode (1) can be used as an inexpensive electrode obtained by suppressing particle dropping/attrition and defects in electrodes for spot welding, in which heat and pressure are applied repeatedly, stably enhancing durability.

Abstract: The present invention is directed to provide a tungsten-based sintered body having a relative density of 99.5% or more (a porosity of 0.5 volume % or less) and a uniform and isotropic structure, which has not been able to be achieved by conventional techniques. In particular, the tungsten-based sintered body is intended for use as a discharge lamp electrode, a sputtering target, a crucible, a radiation shielding member or a resistance welding electrode. The intended tungsten-based sintered body is produced by subjecting a tungsten-based powder to a CIP process at a pressure of 350 MPa or more to form a powder compact, sintering the powder compact in a hydrogen gas atmosphere at a sintering temperature of 1600° C. or more for a holding time of 5 hours or more to form a sintered compact, and subjecting the sintered compact to a HIP process in an argon gas atmosphere under conditions of 150 MPa or more and 1900° C. or more.