Kabushiki Kaisha Toshiba

Mikio Okawa

Tsutomu Okutomi

Atsushi Yamamoto

Tsuneyo Seki

Tadaaki Sekiguchi

Seishi Chiba

Mitsutaka Honma

Hiroshi Endo

Hiromitsu Takeda

Masako Nakahashi

Mitsutaka Homma

Makoto Shirokane

Tatsuo Yamazaki

Tsutomu Yamashita

Kiyofumi Otobe

Shozi Niwa

Yoshinari Satoh

Seiichi Suenaga

Yoshiko Majima

Shigeru Miyakawa

A contact material for a vacuum interrupter includes: (a) from 25 to 70% by volume of a highly conductive component selected from the group consisting of Ag, Cu and combinations thereof, and (b) from 30 to 75% by volume of an arc-proof component comprising a carbide of an element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and combinations thereof, wherein the average grain size of the said arc-proof component is from 0.3 to 3 micrometers and the average grain distance of the arc-proof component is within the range of 0.1 to 1 micrometer. Contacts for a vacuum interrupter obtained from the contact material have improved wear resistance, large current interruption characteristic, wear resistance, and chopping characteristic, and low temperature rise characteristic.

Contact material for a vacuum interrupter

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

Disclosed is a contact material for vacuum circuit breakers and a manufacturing process thereof. The contact material includes a copper component, a chromium component and a bismuth component, and has a metallographic structure comprising: a first phase including the copper component and the bismuth component; and a second phase including the chromium component and interposed among the first phase. In this structure, the boundary surface between the first phase and the second phase appears in a structural cross section of the alloy composition as a substantially smooth boundary line, such that when a segment of the boundary line is defined by two arbitrary points which lie on the boundary line at a straight distance of 10 .mu.m, the ratio of the length of the segment to the straight distance of 10 .mu.m lies within a range of approximately 1.0 to 1.4. Moreover, the boundary line may be approximate to a circle such that the ratio of the length of the boundary line to the length of the circumference of an ideal circle having the same area as the area defined by the boundary line lies within a range of approximately 1.0 to 1.3. In the above contact material, the chromium component is preferably included at a content of approximately 20 % to 60% by weight, and the ratio of the bismuth component to the sum of the bismuth component and the copper component preferably lies within a range of approximately 0.05% to 1.0% by weight.

Contact material for vacuum circuit breakers

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 method of manufacturing a semiconductor device comprising a ceramics cylinder, a metal seal member closing an open end of the cylinder, a semiconductor element located within the cylinder and having electrodes, and leads or electrodes connected to the electrodes of the semiconductor element and extending from the cylinder. The method comprises the steps of coating powder of active metal consisting of Ti and/or Zr on the end face of the ceramics cylinder without heating the ceramics cylinder, in an amount of 0.1 mg/cm.sup.2 to 10 mg/cm.sup.2, mounting a layer of brazing filler metal on the end face of the ceramics cylinder, which have been coated with the powder of the active metal, placing the metal seal member on the layer of brazing filler metal, and heating the ceramics cylinder, the metal seal member, and the layer of brazing filler metal, thereby melting the layer of brazing filler metal and, thus, brazing the metal seal member to the open end of the ceramics cylinder.

Method of manufacturing a semiconductor device

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 method of manufacturing an air-tight ceramic container is disclosed. This method includes the steps of coating an active metal consisting of Ti and/or Zr on an opening end face of a ceramic tubular member in an amount of 0.1 to 10 mg/cm.sup.2, thereby forming an active metal layer, placing a brazing filler metal on the active metal layer, placing a metal cover member for shielding an opening portion of the ceramic tubular member so that a peripheral portion end face of the metal cover member is in contact with the brazing filler metal, and melting the brazing filler metal by heating, thereby brazing the metal cover member to the opening end face of the ceramic tubular member.

Air-tight ceramic container

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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Tama, Japan

Mikio Okawa