Abstract: A cordierite ceramic contains a main component having a composition including Mg of 12.6% by mass or more and 14.0% by mass or less in terms of an oxide, Al of 33.4% by mass or more and 34.4% by mass or less in terms of an oxide and Si of 52.0% by mass or more and 53.6% by mass or less in terms of an oxide, an accessory component having any one of Y, Yb, Er, and Ce in an amount of 4.5% by mass or more and 15.0% by mass or less in terms of an oxide based on 100% by mass of the main component, wherein cordierite, disilicate and spinel are present as crystal phases, a coefficient of thermal expansion of ?120 ppb/° C. to +120 ppb/° C., a four-point bending strength of 170 MPa or more, a low thermal expansion performance and an excellent mechanical strength.

Abstract: A dielectric ceramic includes a main crystal phase containing Ba, Nd and Ti; and a remainder, part of Ti contained in the main crystal phase being substituted with Al, a content of the Al contained in the main crystal phase to a total content of Al in the main crystal phase and the remainder being greater than or equal to 10% on Al2O3 basis. Accordingly, provided is a dielectric ceramic having a high relative permittivity ?r, a high Qf value and a stable resonant-frequency temperature coefficient ?f close to 0 ppm/° C. Also provided is a dielectric filter which is provided with the dielectric ceramic and in which a desired relative permittivity can be obtained with stability and a high Qf value can be obtained, and excellent performance capability can be maintained for a long period of time with stability in a place where wide temperature variations are encountered.

Abstract: Provided is a dielectric ceramic containing yttrium, manganese, and aluminum, and having a composition formula expressed by ?BaO.?Nd2O3.?TiO2, wherein mole ratios ?, ? and ? satisfy 14???21, 4???21, and 65???75, respectively. In this case, the equation: ?+?+?=100 is established.

Abstract: A ceramic sintered body contains Al2O3 crystal grains, internal TiC crystal grains existing in the Al2O3 crystal grains and external TiC crystal grains other than the internal TiC crystal grains. The Al2O3 crystal grains and the external TiC crystal grains retain stress caused by the difference in thermal expansion coefficient remaining after sintering, so that the Al2O3 crystal 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.

Abstract: Provided is a dielectric ceramic containing yttrium, manganese, and aluminum, and having a composition formula expressed by ?BaO.?Nd2O3.?TiO2, wherein mole ratios ?, ? and ? satisfy 14???21, 4???21, and 65???75, respectively. In this case, the equation: ?+?+?=100 is established.

Abstract: Greater emphasis has been placed on smoothness of the floating surface for the applications with floating height of 10 nm or less. To obtain a smooth floating surface, it must be polished with diamond abrasive having a mean particle size of 0.1 ?m or less, and conventional ceramic sintered body has poor machinability and it is impossible to use the magnetic heads made of this ceramic sintered body at a floating height of 10 nm or less. The ceramic sintered body according to the present invention contains Al2O3 crystal grains, internal TiC crystal grains existing in the Al2O3 crystal grains and external TiC crystal grains other than the internal TiC crystal grains. The Al2O3 crystal grains and the external TiC crystal grains retain stress caused by the difference in thermal expansion coefficient remaining after sintering, so that the Al2O3 crystal grains and the external TiC crystal grains pull each other in the interface therebetween.

Abstract: The present invention relates to a magnetic head substrate comprising a sintered body containing 35% by mass to 60% by mass of alumina and 40% by mass to 65% by mass of a conductive compound. The conductive compound contains at least one selected from carbide, nitride and carbonitride of tungsten. The sintered body has a maximum crystal particle size of 4 ?m or less (except for 0 ?m). Furthermore, the present invention provides a magnetic head provided with a slider formed of the magnetic head substrate and a recording medium driving device provided with the magnetic head.

Abstract: 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 ∈r and Q factor in a high frequency region, and decrease the absolute value of the temperature factor &tgr;f of resonant frequency.

Abstract: 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.

Abstract: 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.

Abstract: 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 &egr;r and Q factor in a high frequency region, and decrease the absolute value of the temperature factor &tgr;f of resonant frequency.