Tdk Corporation

Naoto Oji

Takahiro Mori

Tatsuya Kato

Takashi Kojima

Takeshi Nomura

Hiroyuki Morita

Yoshihiko Minachi

Akira Sato

Nobuhiro Suto

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

A non-reductive dielectric ceramic material having a main component represented by [(Ca.sub.X Sr.sub.1-X)O].sub.m [(Ti.sub.Y Zr.sub.1-Y)O.sub.2 ] wherein X, Y and m fulfills 0.ltoreq.X.ltoreq.1, 0.ltoreq.Y.ltoreq.0.10 and 0.75.ltoreq.m.ltoreq.1.04, and auxiliary component containing 0.2-5 mol % (calculated MnO) of Mn oxide, 0.1-10 mol % (calculated as Al.sub.2 O.sub.3) of Al oxide and 0.5-15 mol % of a component of formula [(Ba.sub.Z Ca.sub.1-Z)O].sub.V SiO.sub.2 wherein 0.ltoreq.Z.ltoreq.1 and 0.5.ltoreq.V.ltoreq.4.0; and when used in a laminated ceramic condenser using a base metal such as Ni as inner electrode, can be sintered at a temperature not exceeding 1,300.degree. C., shows a small temperature coefficient of capacitance, can be controlled arbitrarily in the range of -150 to +150 ppm/.degree. C., has a specific resistance of no less than 1.times.10.sup.13 .OMEGA.cm at 25.degree. C., displays a small frequency-dependence of dielectric constant and dielectric loss tangent (tan .delta.) and has a long accelerated lifetime of insulating resistance.

Non-reducing dielectric ceramic materials

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Tokyo, Japan

Naoto Oji