Kyocera Corporation

Toshiyuki Sue

Yoshihiro Okawa

Masahide Akiyama

Shuji Nakazawa

Takuya Gentsu

Yucong Wang

Hajime Toda

Kouji Enokida

Provided is a dielectric ceramic containing yttrium, manganese, and aluminum, and having a composition formula expressed by &#x3b1;BaO.&#x3b2;NdO.&#x3b3;TiO, wherein mole ratios &#x3b1;, &#x3b2; and &#x3b3; satisfy 14&#x2266;&#x3b1;&#x2266;21, 4&#x2266;&#x3b2;&#x2266;21, and 65&#x2266;&#x3b3;&#x2266;75, respectively. In this case, the equation: &#x3b1;+&#x3b2;+&#x3b3;=100 is established.

Dielectric ceramic, and resonator using the same

A ceramic sintered body contains AlOcrystal grains, internal TiC crystal grains existing in the AlOcrystal grains and external TiC crystal grains other than the internal TiC crystal grains. The AlOcrystal grains and the external TiC crystal grains retain stress caused by the difference in thermal expansion coefficient remaining after sintering, so that the AlOcrystal grains and the external TiC crystal grains pull each other in the interface therebetween. As a result, when the ceramic sintered body is machined, micro-cracks generated in the interface can easily grow due to the residual stress in addition to the shearing force caused by the machining operation, so that machinability is improved.

Ceramic sinter, magnetic head substrate using the same, magnetic head and recording medium drive unit

The dielectric ceramic material of the present invention is constituted from a solid solution of which dominant crystal phase is a perovskite crystal, and the perovskite crystal consists of complex oxide of at least Ba, Sr, Mg, W and rare earth element, and is preferably used for dielectric resonator since this dielectric ceramic material makes it possible to achieve a high values of &isin;r and Q factor in a high frequency region, and decrease the absolute value of the temperature factor &tgr;f of resonant frequency.

Dielectric ceramic material and dielectric resonator using the same

The electromagnetic wave absorber of the present invention is made of a sintered body that contains Fe and at least one element selected from Si, Mg, Zr, Ni, Al and Co, and an attenuation of electromagnetic wave is 2 dB or more at frequencies of 10 GHz and higher so as to provide good electromagnetic wave absorbing characteristic with no corrosive gas generated at all, and is easy to manufacture. The electromagnetic wave absorber is used mainly as a component of a high-frequency circuit package.

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Kirishima, Japan

Toshiyuki Sue