Nippon Tungsten Co., Ltd.

Nisshin Steel Co., Ltd.

Shuichi Teramoto

Hiroshi Asada

Jun Kurobe

Kenji Okamura

Shigeo Matsubara

Shouji Inoue

Yasutsugu Ueno

Akira Matsuo

Keiji Hara

Keiichi Ozuka

Shingo Mukae

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&#x3c;d&#x2266;2.5 &#x3bc;m. Given a volume fraction f (vol %) of the total amount of the oxide particles in the tungsten cathode material, 0.083&#x2266;f/I holds when a current I(A) such that 0&#x3c;I&#x2266;40 A is applied to an electrode being made of the tungsten cathode material.

Tungsten cathode material

Provided is an electrode () which has a double structure including Cu or a Cu alloy as an electrode body () and a core material () made of W, Mo, a W-based alloy, or a Mo-based alloy embedded in a surface of the electrode body () which is abutted against a material to be welded, the core material () 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 &#x3bc;m or more and an aspect ratio of 1.5 or more. The electrode () 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.

Electrode for spot welding

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Fukuoka, Japan

Shuichi Teramoto