Tdk Corporation

Nobuhiro Suto

Takahiro Mori

Hiroyuki Morita

Yoshihiko Minachi

Shigeki Yanagida

Tatsuya Katoh

Tatsuya Kato

Naoto Oji

A ferrite magnet and a ferrite sintered magnet including a ferrite magnetic material are provided. A main phase of the ferrite magnetic material includes a ferrite phase having a hexagonal crystal structure, and metal element composition expressed by Ca1-w-x-yR wSr xBayFezMm wherein 0.25&#x3c;w&#x3c;0.5, 0.01&#x3c;x&#x3c;0.35, 0.0001&#x3c;y&#x3c;0.013, y&#x3c;x, 8.7&#x3c;z&#x3c;9.9, 1.0&#x3c;w/m&#x3c;2.1, 0.017&#x3c;m/z&#x3c;0.055 and Si component is at least included as a sub-component, and wherein; when content y1 mass % of the Si component in the ferrite magnetic material, with respect to SiO2, is shown on Y-axis and a total content x1 of z and m is shown on X-axis, a relation between x1 and y1 is within a range surrounded by 4 points placed on X-Y coordinate having the X and Y axes.

Ferrite magnetic material, ferrite magnet, and ferrite sintered magnet

The present invention aims to ensure strength of a thin-walled sintered magnet. A sintered magnet is a ferrite sintered magnet made by sintering a magnetic material. A magnetic powder mixture obtained by mixing magnetic powder with a binder resin is injection-molded into a mold with a magnetic field applied thereto to produce a molded body, which is then sintered to produce the sintered magnet. The sintered magnet has a thickness of 3.5 mm or less in the position of center of gravity thereof. The sintered magnet has a surface roughness Rz of 0.1 &#x3bc;m or more and 2.5 &#x3bc;m or less. The surface roughness Rz is a 10 point average roughness.

Sintered magnet and method for producing the sintered magnet

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Tokyo, Japan

Nobuhiro Suto