Jfe Mineral Company, Ltd.

Kawatetsu Mining Co., Ltd.

Morishige Uchida

In an ultrafine metal powder slurry containing an organic solvent, a surfactant, and an ultrafine metal powder, the surfactant is oleoyl sarcosine, the content of the ultrafine metal powder in the ultrafine metal powder slurry is 70 to 95 percent by mass, and more than 0.05 to less than 2.0 parts by mass of the surfactant is contained relative to 100 parts by mass of the ultrafine metal powder. By the above slurry, reduction in labor and treatment time can be realized in a conductive paste forming process. In addition, since aggregation of particles of the ultrafine metal powder is prevented, an ultrafine metal powder slurry can be provided having superior dispersibility and dry film density.

Ultrafine metal powder slurry

The present invention improves the oxidation resistance of an ultrafine metal powder for use in the internal electrode of a multilayer ceramic capacitance and suppresses an increase in the thickness of a metal internal electrode film resulting from the spheroidization of the molten metal under surface tension during the formation of the metal internal electrode film. The ultrafine metal powder has a sulfur-containing compound of not less than one element selected from the group consisting of Y, Zr, and La present on the surface of the particle thereof and is produced by performing an ultrafine metal powder purification step of dispersing the ultrafine metal powder in a slurry, a surface treatment step of adding an aqueous solution containing a sulfate of not less than one element selected from the group consisting of Y, Zr, and La to the slurry to form the compound on the surface of the metal particle, a filtering step, and a drying step.

Surface-treated ultrafine metal powder, method for producing the same, conductive metal paste of the same, and multilayer ceramic capacitor using said paste

An ultrafine metal powder slurry with high dispersibility includes an organic solvent; a surfactant having a hydrophilic group and a lipophilic group; and an ultrafine metal powder in an amount more than 60% by mass and less than 95% by mass. In the slurry, the hydrophilic group of the surfactant is at least one selected from a sulfonato group, sulfo group, sulfonyldioxy group, polyoxyethylene group with carboxyl group, and polyoxyethylene group with phosphate group, and the lipophilic group is an alkyl containing 12 or more carbon atoms or an alkylphenyl. The ultrafine metal powder slurry includes no aggregated particles, exhibits good dispersibility and is useful as a metal material for conductive pastes. The slurry can save a part of process steps in conventional conductive paste production processes, can shorten a process time and can save in labor.

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Chiba, Japan

Morishige Uchida