Dowa Electronics Materials Co., Ltd.

Shinichi Konno

Kenichi Inoue

Toshihiko Ueyama

Ken Inoue

Shinya Sasaki

Takayuki Yoshida

Takashi Hinotsu

Kenji Masada

Koji Tanoue

Hidefumi Fujita

Shingo Teragawa

Daisuke Itoh

Yu Murano

Taro Torigoe

There is produced a fine silver particle dispersing solution which contains: fine silver particles (the content of silver in the fine silver particle dispersing solution being 30 to 95% by weight), which have an average primary particle diameter of greater than 100 nm and not greater than 300 nm and which are coated with an amine having a carbon number of 8 to 12, such as octylamine, serving as an organic protective material; a polar solvent (5 to 70% by weight) having a boiling point of 150 to 300&#xb0; C.; and an acrylic dispersing agent (5% by weight or less with respect to the fine silver particles), such as a dispersing agent of at least one of acrylic acid ester and methacrylic acid ester.

Fine silver particle dispersing solution

A silver particle dispersing solution, which contains 50-70% by weight of silver particles having an average particle diameter of 20 nm or less, is applied on a substrate by the flexographic printing, and then, calcined to produce a booster antenna wherein a silver conductive film, which contains 10-50% by volume of a sintered body of the silver particles and which has a volume resistivity of 3-100 &#x3bc;&#x3a9;&#xb7;cm, a surface resistivity of 0.5&#x3a9;/&#x25a1; or less and a thickness of 1-6 &#x3bc;m, is formed on the substrate. Thus, there is provided a booster antenna which has excellent electrical characteristics and flexibility and which can be inexpensively mass-produced.

Booster antenna and method for producing same

A magnetic powder for magnetic recording medium comprises acicular particles constituted primarily of Fe, wherein the powder contains Co in an amount such that the Co/Fe ratio is 50 at. % or less and the Co is contained in a manner such that the surface portion has a higher concentration than the core portion of the particles, and upon subjecting the magnetic powder for magnetic recording medium to TG measurement, the powder exhibits at least two oxidation starting points: a low-temperature side oxidation starting point and a high-temperature side oxidation starting point. The magnetic powder achieves improved resistance to oxidation without sacrificing magnetic characteristics.

Method of producing magnetic powder for magnetic recording medium

Non-magnetic powder of particles for non-magnetic lower layer applications is provided that enables a multilayer coating type magnetic recording medium having good surface smoothness to be obtained. The particles are iron compound particles having a long axis with a standard geometrical deviation, as obtained from a transmission electron microscope image, that is greater than 1.5, and a short axis with a standard geometrical deviation, as obtained from a TEM image, that is greater than 1.35. The iron compound particles may be hematite or iron oxyhydroxide.

Iron compound particles and magnetic recording medium using same

A ferromagnetic metal powder for a magnetic recording medium that combines good magnetic properties and oxidation stability, and a magnetic recording medium using the powder. A method of producing the magnetic powder comprises using oxygen to form an oxide film, then changing the state of the oxide film by using moderate gas phase activation treatment in an active gas, using, for example, CO or Hor other such gas having reducing properties. ESCA-based measurements show that the binding energy peak of the powder is more to the low energy side compared to when the above treatment is not used, showing that the oxide film has oxidation resistance. The storage stability of a magnetic recording medium is improved by using the powder.

Ferromagnetic powder for a magnetic recording medium, method of producing the powder, and magnetic recording medium using the powder

A nonmagnetic powder, used for the nonmagnetic layer of a coated type magnetic recording medium having a multilayer structure, has good dispersibility in the binder in which it is dispersed to prepare a coating material that is applied to the nonmagnetic layer. The nonmagnetic powder has an iron compound as its principal component and exhibits a maximum pore volume value in a pore diameter range of 0.01 &#x3bc;m to 0.05 &#x3bc;m within a pore diameter range of 0.0018 &#x3bc;m to 0.1 &#x3bc;m in which the relationship between pore diameter and pore volume is calculated by a mercury injection method. The nonmagnetic powder exhibits a cumulative pore volume value in a pore diameter range of 0.0018 &#x3bc;m to 0.01 &#x3bc;m that is not more than 30% of the cumulative pore volume value in the pore diameter range of 0.0018 &#x3bc;m to 0.1 &#x3bc;m.

Nonmagnetic powder comprising acicular iron and having specific porosity for a magnetic recording medium, method of manufacturing same, and magnetic recording medium using same

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Honjo, Japan

Shinichi Konno