Kabushiki Kaisha Toshiba

Tadaaki Sekiguchi

Tsutomu Okutomi

Atsushi Yamamoto

Tsuneyo Seki

Mikio Okawa

Seishi Chiba

Hiroshi Endo

Mitsutaka Honma

Tsutomu Yamashita

Kiyofumi Otobe

Yoshinari Satoh

Yoshiko Majima

The contacts material of the present invention is contacts material including silver-tungsten carbide alloy containing 55-70 weight % of tungsten carbide (WC) of mean particle size 0.1-6 .mu.m wherein is included 0.005-0.2 weight % of carbon in an undissolved state or non-compound state whose equivalent diameter is 0.01-5 .mu.m. The present invention enables the current interruption characteristics of contacts material to be improved.

Contacts material

Disclosed is a manufacturing process of an alloy material comprising a chromium component and a base component which comprises at least one element selected from tile group consisting of copper and silver, the manufacturing process comprising steps of: subjecting a chromium material with a carbon material to heat treatment; and manufacturing the alloy material using the chromium material treated at the heat treatment subjecting step and a raw material for tile base component. At the heat treatment subjecting step, the chromium material, mixed with 50 ppm to 5,000 ppm of the carbon material, is heated to a temperature within the range of 800.degree. C. to 1,400.degree. C. in a non-oxidizing atmosphere. According to this manufacturing process, the level of oxygen content in the alloy material are decreased to be not more than 200 ppm. The obtained alloy material can be used as a contact material for vacuum circuit breakers.

Process for manufacturing a contact material for vacuum circuit breakers

The present invention relates to a contact for a vacuum interrupter obtained by processing a contact-forming material comprising from 20% to 60% by weight of Cr, Bi in an amount of from 0.05% to 1.0% by weight of the total amount of Cu and Bi, and the balance substantially Cu into the shape of a contact, and thereafter subjecting the processed material to vacuum heat treatment. The contact for the vacuum interrupter has both excellent anti-welding characteristics and excellent voltage withstanding characteristics.

Contact for a vacuum interrupter

An Ag-Cu-WC contact forming material for a vacuum interrupter comprising a highly conductive component comprising Ag and Cu and an arc-proof component comprising WC wherein the content of the highly conductive component is such that the total amount of Ag and Cu(Ag+Cu) is from 25% to 65% by weight and the percentage of Ag based on the total amount of Ag and Cu[Ag/(Ag+Cu)] is from 40% to 80% by weight; wherein the content of the arc-proof component is from 35% to 75% by weight; wherein the structure of the highly conductive component comprises a matrix and a discontinuous phase, the discontinuous phase having a thickness or width of no more than 5 micrometers and wherein said arc-proof component comprises a discontinuous grain having a grain size of no more than 1 micrometer.

Contact forming material for a vacuum interrupter

A contact forming material for a vacuum interrupter comprising: from 25% to 65% by weight of a highly conductive component comprising Ag and Cu, and from 35% to 75% by weight of an arc-proof component selected from the group consisting of Ti, V, Cr, Zr, Mo, W and their carbides and borides, and mixtures thereof wherein the highly conductive component of the contact forming material comprises (i) a first highly conductive component region composed of a first discontinuous phase having a thickness or width of no more than 5 micrometers and a first matrix surrounding the first discontinuous phase, and (ii) a second highly conductive component region composed of a second discontinuous phase having a thickness or width of at least 5 micrometers and a second matrix surrounding the second discontinuous phase, wherein the first discontinuous phase in the first highly conductive component region is finely and uniformly dispersed in the first matrix at intervals of no more than 5 micrometers, and wherein the amount of the second highly conductive component region based on the total highly conductive component is within the range of from 10% to 60% by weight.

A contact forming material for a vacuum valve or vacuum circuit breaker comprising (a) a conductive material consisting of copper and/or silver, and (b) an arc-proof material consisting of chromium, titanium, zirconium, or an alloy thereof wherein the amount of said arc-proof material present in said conductive material matrix is no more than 0.35% by weight. This contact forming material is produced by a process which comprises the steps of compacting arc-proof material powder into a green compact, sintering said green compact to obtain a skeleton of the arc-proof material, infiltrating the voids of said skeleton with a conductive material, and cooling the infiltrated material. The contact forming material can provide contacts for a vacuum valve or vacuum circuit breaker which has excellent characteristics such as temperature rise characteristic and contact resistance characteristic.

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Yokohama, Japan

Tadaaki Sekiguchi