Dowa Electronics Materials Co., Ltd.

Fujifilm Corporation

Shuji Kaneda

Hiroyuki Suzuki

Toshio Tada

Yutaka Hisaeda

Hirohisa Omoto

Kimikazu Motomura

Tatsuya Kariyasu

Kosuke Iha

Hidefumi Fujita

Satoshi Shiki

Daisuke Itoh

Provided is an Al-containing hexagonal ferrite magnetic powder which produces an excellent durability-improving effect on a magnetic recording medium, wherein uniform pulverization of the magnetic powder can be easily achieved by dispersion treatment in preparation of a magnetic coating material even in cases where the magnetic powder has a small primary particle size or has a composition which is likely to produce hard secondary particles. The magnetic powder for a magnetic recording medium is an Al-containing hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, and has a particle size distribution in which the volume ratio of particles having a particle size of 30 μm or more as measured by a laser diffraction particle size distribution analyzer with a dispersion pressure of 100 kPa is 5.0% or less, and an activation volume Vact of 1800 nmor less.

Magnetic powder for magnetic recording medium

Provided is a hexagonal ferrite magnetic powder for a magnetic recording medium, containing hexagonal ferrite magnetic particles having aluminum hydroxide adhered on the surface thereof, the hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, a Co/Fe molar ratio of 0.002 to 0.030, and a Nb/Fe molar ratio of 0.005 to 0.050, and having an Fe site valence Aof 3.015 to 3.040 as calculated by A=(3+2&#xd7;[Co/Fe]+5&#xd7;[Nb/Fe])/(1+[Co/Fe]+[Nb/Fe]) wherein [Co/Fe] represents the Co/Fe molar ratio and [Nb/Fe] represents the Nb/Fe molar ratio, and preferably having an activation volume Vact of 1400 to 1800 nm. This magnetic powder simultaneously achieves an increase in magnetic characteristics including SNR of a magnetic recording medium and a further increase in durability thereof.

Hexagonal ferrite magnetic powder

After there is prepared a conductive paste which contains fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, coarse copper particles having an average particle diameter of 0.3 to 20 &#x3bc;m, a glycol solvent, such as ethylene glycol, and at least one of a polyvinylpyrrolidone (PVP) resin and a polyvinyl butyral (PVB) resin and wherein the total amount of the fine copper particles and the coarse copper particles is 50 to 90% by weight, the weight ratio of the fine copper particles to the coarse copper particles being in the range of from 1:9 to 5:5, the conductive paste thus prepared is applied on a substrate by screen printing to be preliminary-fired by vacuum drying, and then, fired with light irradiation by irradiating with light having a wavelength of 200 to 800 nm at a pulse period of 500 to 2000 &#x3bc;s and a pulse voltage of 1600 to 3800 V to form a conductive film on the substrate.

Conductive paste and method for producing conductive film using same

A method suitable for mass production of nanoparticles with a uniform particle diameter is provided. It is an object to provide a powder of the nanoparticle obtained by this method, a dispersion containing the nanoparticles, and a paste containing the nanoparticles. There is provided a method for manufacturing silver particles including the step of reducing silver in a silver solution containing a protective agent composed of an organic material and a copper component in an amount of 1 to 1,000 ppm relative to the amount of silver to obtain particles having an average particle diameter (D) of 5 to 100 nm as measured using a transmission electron microscope.

Fine silver particle powder, method for manufacturing the same, silver paste using the powder and method of use of the paste

Fine silver particle powder, method for manufacturing the same, silver paste using the powder, and method of use of the paste

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Okayama, Japan

Shuji Kaneda