Kawasaki Steel Corporation

Bridgestone Corporation

Hitomi Hatano

Tasuku Saito

Takayuki Maruyama

Yuichi Ishino

Takashi Haraoka

Takao Ogino

Katsuhiro Nagayama

Shigeru Takano

Kenichi Uehara

Noriyoshi Fukuda

Takayuki Torii

Kaori Takagi

Yasunobu Iizuka

A fuel cell separator including (a) about 100 parts by weight of graphitized meso-carbon microbeads, (b) about 10 to 35 parts by weight of one of a thermosetting resin and a thermoplastic resin, and (c) about 1 to 40 parts by weight of at least one carbonaceous material selected from the group consisting of graphite powder, carbon black, and fine carbon fibers. The fuel cell separator exhibits low electrical resistivity, low volume resistivity, superior gas impermeability, and superior dimensional accuracy without a graphitizing treatment after molding. A fuel cell using the fuel cell separators can be produced while saving energy using a simplified facility and has superior generation efficiency.

Fuel cell separator, a fuel cell using the fuel cell separator, and a method for making the fuel cell separator

An electrorheological fluid is constituted by using a dispersed phase of a carbonaceous powder having an oxygen content above 10% by weight but not more than 20% by weight and having an average particle diameter of 0.01-100 .mu.m, obtained by: heat-polymerizing a condensed polycyclic aromatic compound containing a main component of naphthalene by using HF/BF.sub.3 as a catalyst to obtain a 100% meso-phase pitch having a softening point within a range of 150.degree.-400.degree. C.; heat-treating and making the pitch infusible in an oxidizing atmosphere at a temperature not more than a fusing temperature of the pitch and not less than 50.degree. C. but not more than 400.degree. C. to allow the pitch to have an oxygen content of 12-25% by weight; and then heat-treating and carbonizing the pitch in an inert gas atmosphere at a temperature not less than 300.degree. C. but not more than 700.degree. C. It is thus possible to obtain an electrorheological fluid having low current consumption, a high electrorheological effect and excellent long-term durability, even when the carbonaceous powder having high oxidation resistance and a high oxygen content is used.

Carbonaceous powder to be dispersed in electrorheological fluid and

A method for producing a carbonaceous powder which can be used as dielectric fine particles to be dispersed in an insulating oil to produce an electrorheological fluid is provided. The method comprises the steps of subjecting a starting organic material selected from the group consisting of coal, coal tar, coal tar pitch, liquefied coal, coke, petroleum, petroleum tar, petroleum pitch, and resins to a heat treatment at a maximum temperature of 300.degree. to 800.degree. C. to produce carbonaceous material; pulverizing and classifying the material to produce carbonaceous particles having a mean particle size of 0.5 to 40 .mu.m and a maximum particle size of up to 50 .mu.m; and subjecting the particles to an additional treatment at an elevated temperature and/or a reduced pressure, said additional treatment being carried out at a temperature lower than said maximum temperature of the heat treatment. The resulting carbonaceous powder may optionally be subjected to a further pulverization treatment.

Method for producing carbonaceous powder for electrorheological fluid

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Chiba, Japan

Hitomi Hatano