The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiO-Ta.sub.2O.sub.5-based microwave dielectric ceramic material sintered at low temperature and its preparation method. It is guided by ion doping modification, not only considering the substitution of ions with similar radius, such as Zn.sup.2+ replacing Ni.sup.2+ ions, V.sup.5+ replacing Ta.sup.5+ ions; Meanwhile, the selected doped oxide still has the property of low melting point. Therefore, the microwave dielectric properties of NiO-Ta.sub.2O.sub.5-based ceramic material can be improved and the appropriate sintering temperature can be reduced. In the invention, by adjusting the molar content of each raw material, the NiO-Ta.sub.2O.sub.5-based ceramic material with low-temperature sintering, stable temperature and excellent microwave dielectric property is directly synthesized at one time, which can be widely applied to the technical field of LTCC.

The present invention relates to parts of transparent corundum ceramics and the production and use of said parts.

Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

A Li ion conductor having a composition different from a conventional composition is provided. The Li ion conductor contains at least one selected from a group Q consisting of Ga, V, and Al, Li, La and O. A part of an Li site is optionally substituted with a metal element D, a part of an La site is optionally substituted with a metal element E, and parts of Ga, V and Al sites are optionally substituted with a metal element J. A mole ratio of an amount of Li to a total amount of La, the element E, Ga, V, Al, and the element J is not lower than 8.1/5 and not higher than 9.5/5. A mole ratio of a total amount of Ga, V, and Al to a total amount of La and the element E is not lower than 1.1/3 and not higher than 2/3.

Disclosed are a multi-layer composite ceramic plate and a manufacturing method thereof. The composite ceramic plate includes at least one basic sandwich structure. The manufacturing method includes: preparing a sheet-like green body with ceramic powders; pre-sintering the green body at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic member with certain strength; forming a metal electrode layer on an upper surface of the pre-sintered ceramic member; placing the pre-sintered ceramic member in a mold, with the upper surface coated with the metal electrode layer facing upwards; providing a ceramic precursor layer on the upper surface of the pre-sintered ceramic member; carrying out hot-pressing sintering in the axial direction of the pre-sintered ceramic member at the sintering temperature to form an integral structure, wherein by the hot-pressing sintering, a second ceramic layer is formed by the pre-sintered ceramic member, a first ceramic layer is formed by the ceramic precursor layer, and the metal electrode layer is located between the first ceramic layer and the second ceramic layer to from a basic sandwich structure together with the first ceramic layer and the second ceramic layer.

A temperature-stable modified NiO—Ta.sub.2O.sub.5-based microwave dielectric ceramic material and a preparation method thereof are provided. Using ion doping modification to form solid solution structure is an important measure to adjust microwave dielectric properties, especially the temperature stability. Based on formation rules of the solid solution, ion replacement methods are designed including Ni.sup.2+ ions are replaced by Cu.sup.2+ ions, and (Ni.sub.1/3Ta.sub.2/3).sup.4+ composite ions are replaced by [(Al.sub.1/2Nb.sub.1/2).sub.ySn.sub.1-y].sup.4+ composite ions, which considers that cations with similar ionic radii to Ni.sup.2+ and Ta.sup.5+ ions can be introduced into the NiTa.sub.2O.sub.6 ceramic for doping under the same coordination environment (coordination number=6), and therefore a ceramic material with the NiTa.sub.2O.sub.6 solid solution structure can be obtained. The microwave dielectric ceramic material with excellent temperature stability and low loss is finally prepared by adjusting molar contents of each of doped ions, and its microwave dielectric properties are excellent.

A method of fabricating a fiber preform filled with refractory ceramic particles, includes placing a fiber texture including refractory ceramic fibers in a mold cavity; injecting a slip including a powder of refractory ceramic particles present in a liquid medium, the slip being injected into the pores of the fiber texture present in the mold cavity, injection being performed through at least a first face or a first edge of the fiber texture; and draining the liquid medium of the slip that has penetrated into the fiber texture through the porous material part, the draining being performed at least through a second face or a second edge of the fiber texture different from the first face or the first edge, the porous material part also serving to retain the refractory particle powder in the pores of the fiber texture to obtain a fiber preform filled with refractory particles.

Provided is an inorganic structure including a plurality of inorganic particles; and a binding part that covers a surface of each of the inorganic particles and binds the inorganic particles together, wherein the binding part contains: an amorphous compound containing silicon, oxygen, and one or more metallic elements; and fine particles having an average particle size of 100 nm or less. Also provided is a method for producing an inorganic structure including: a step for obtaining a mixture by mixing a plurality of inorganic particles, a plurality of amorphous silicon dioxide particles, and an aqueous solution containing a metallic element; and a step for pressurizing and heating the mixture under conditions of a pressure of 10 to 600 MPa and a temperature of 50 to 300° C.

A piezoelectric material including a perovskite-type metal oxide represented by the following general formula (1); Bi; and Mn, wherein the content of Bi is 0.1-0.5 mol % with respect to 1 mol of the metal oxide, the content of Mn is 0.3-1.5 mol % with respect to 1 mol of the metal oxide, and the piezoelectric material satisfies (L.sub.4−L.sub.5)/L.sub.5≧0.05 and (L.sub.8−L.sub.9)/L.sub.9≧0.05 when the lengths of twelve Bi—O bonds with Bi that is located at a 12-fold site with respect to O in a perovskite-type unit cell as a starting point are taken to be L.sub.1 to L.sub.12 in length order:

(Ba.sub.1-xM1.sub.x)(Ti.sub.1-yM2.sub.y)O.sub.3  (1)

wherein 0≦x≦0.2, 0≦y≦0.1, and M1 and M2 are mutually different metal elements which have a total valence of +6 and are selected from other elements than Ba, Ti, Bi and Mn.

Translucency of a yttria-stabilized zirconia ceramic is improved to achieve even higher translucency than what is currently offered on the market, without greatly altering its mechanical properties. The enhancement is done by incorporating magnesium-containing dopants into the microstructure of yttria-stabilized zirconia ceramic dental ceramics.