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.

It is described a process for producing transparent ceramic bodies with at least two zones having different garnet composition, in particular in which one of said zones has composition Y.sub.3AI.sub.5O.sub.12. The invention is especially useful for the production of transparent ceramic bodies having preset complex shapes and/or a controlled complex distribution of doping ions.

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.

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.

Disclosed is a method of manufacturing a ceramic powder, which includes forming a slurry by mixing of first ceramic particles, binder and water, spraying and drying the slurry to form a first ceramic core portion, and thermally treating and shaping the first ceramic core portion. The first ceramic core portion has a first flexural strength and a first coefficient of thermal expansion. The method further includes forming another slurry to form a second ceramic shell portion formed by second ceramic particles and covering the first ceramic core portion. The second ceramic shell portion has a second flexural strength and a second coefficient of thermal expansion. The ceramic powder is formed by thermally treating and shaping the first ceramic core portion and the second ceramic shell portion.

The present invention relates to a method for producing a three-dimensional macroporous filament construct having interconnected microporous filaments showing a suitable surface roughness and microporosity. The method includes the steps of: a) preparing a suspension having particles of a predetermined material, a liquid solvent, one or more binders and optionally one or more dispersants, b) depositing the suspension in the form of filaments in a predetermined three-dimensional pattern, preferably in a non-solvent environment, thereby creating a three-dimensional filament-based porous structure, c) inducing phase inversion, whereby said filaments are transformed from a liquid to a solid state, by exposing the filaments during the deposition of the filaments with a non-solvent vapour and to a liquid non-solvent, d) thermally treating the structure of step d) by calcining and sintering the structure. The invention further provides a three-dimensional macroporous filament construct having interconnected microporous filaments showing a specific surface roughness and microporosity. The invention also relates to various uses of the construct, including its use for the manufacture of a biomedical product, such as a synthetic bone implant or bone graft.

The present invention relates to a method for producing a three-dimensional macroporous filament construct having interconnected microporous filaments showing a suitable surface roughness and microporosity. The method includes the steps of: a) preparing a suspension having particles of a predetermined material, a liquid solvent, one or more binders and optionally one or more dispersants, b) depositing the suspension in the form of filaments in a predetermined three-dimensional pattern, preferably in a non-solvent environment, thereby creating a three-dimensional filament-based porous structure, c) inducing phase inversion, whereby said filaments are transformed from a liquid to a solid state, by exposing the filaments during the deposition of the filaments with a non-solvent vapour and to a liquid non-solvent, d) thermally treating the structure of step d) by calcining and sintering the structure. The invention further provides a three-dimensional macroporous filament construct having interconnected microporous filaments showing a specific surface roughness and microporosity. The invention also relates to various uses of the construct, including its use for the manufacture of a biomedical product, such as a synthetic bone implant or bone graft.

Disclosed are methods for forming boron nitride-containing aggregates that exhibit improved wear by attrition, and resulting filled polymers that exhibit significantly improved thermal conductivity. The boron nitride-containing aggregates are prepared according to a method that includes wet granulating boron nitride powder with a granulation solution to form wet boron nitride-containing granules; and drying the wet boron nitride-containing granules to cause evaporation of solvent in the granulation solution, thereby forming boron nitride-containing granules. Sintering achieves the desired boron nitride-containing aggregates.

According to an example, a composition may include a high melt temperature build material in the form of a powder; a first low melt temperature binder in the form of a powder; and a second low melt temperature binder in the form of a powder; and in which the first low melt temperature binder melts at a temperature that is different from the second low melt temperature binder.