A method for producing a photo-luminescent material, including the following steps: (1) producing, according to a sol-gel method, a sol and then a gel of first precursors of a first substance from the sol; (2) crushing the gel; (3) optionally, annealing the gel in order to form first particles of the first substance of which the average size is between 1 pm and 20 um; (4) producing a colloidal dispersion of second particles of a second substance, different from the first substance or identical to the first substance, of which the average size is between 5 nm and 400 nm; (5) mixing the colloidal dispersion with the sol in step (1) before forming the gel or with the first particles after step (3); and (6) annealing the mixture obtained in step (5), resulting in an increase in the compactness of the mixture, the average size of the second particles after annealing being between 100 nm and 900 nm. A photo-luminescent material including a mixture of first particles of a first photo-luminescent substance of which the average size is between 1 pm and 20 pm and second particles of a second photo-luminescent substance, different from the first photo-luminescent substance or identical to the first photo-luminescent substance, of which the average size is between 100 nm and 900 nm.

The present invention provides a piezoelectric material not containing lead and potassium, having a high relative density, a high Curie temperature, and a high mechanical quality factor, and exhibiting good piezoelectricity. The piezoelectric material contains 0.04 percent by mole or more and 2.00 percent by mole or less of Cu relative to 1 mol of metal oxide represented by General formula (1) below.
((Na.sub.1-zLi.sub.z).sub.xBa.sub.1-y)(Nb.sub.yTi.sub.1-y)O.sub.3 (in Formula, 0.70≦x≦0.99, 0.75≦y≦0.99, and 0<z<0.15, and x<y)  General formula (1)

A method of making a proppant may include adding a dry ceramic precursor to a granulator, adding a slurry to the granulator, granulating the dry ceramic precursor and the slurry to form densified granules, and firing the densified granules to form a ceramic proppant. The dry ceramic precursor may include an alumina- or aluminosilicate-containing material, such as, for example, at least one of kaolin, ball clay, bauxitic kaolin, smectite clay, bauxite, gibbsite, boehmite, metakaolin, or diaspora. The slurry may include a recycled proppant material, such as, a fired recycled proppant material or a green recycled proppant material.

A dielectric thin film containing MgO as a main component, wherein the dielectric thin film is composed of a columnar structure group containing at least one columnar structure A constructed by single crystal and at least one columnar structure B constructed by polycrystal, respectively, and in the cross section of the direction perpendicular to the dielectric thin film, when the area occupied by the columnar structure A is set as C.sub.A and the area occupied by the columnar structure B is set as C.sub.B, the relationship between C.sub.A and C.sub.B satisfies 0.4≦C.sub.B/C.sub.A≦1.1.

Provided is a zirconia sintered body that suppresses discoloration due to porcelain. The zirconia sintered body comprises at least one of a coloring agent A: erbium oxide and a coloring agent B: nickel oxide, and a composite oxide of zirconium and vanadium.

Electronic devices are produced from dielectric compositions comprising a mixture of precursor materials that, upon firing, forms a dielectric material comprising a barium-strontium-titanium-tungsten-silicon oxide.

To provide a zirconia sintered body having both excellent translucency and bending strength, specifically a zirconia sintered body having both translucency and strength suitable as a denture for front tooth, and a process for its production. A translucent zirconia sintered body containing more than 4.0 mol % and at most 6.5 mol % of yttria and less than 0.1 wt % of alumina, and having a relative density of at least 99.82%, a total light transmittance of at least 37% and less than 40% to light with a wavelength of 600 nm at a thickness of 1.0 mm, and a bending strength of at least 500 MPa, and a process for its production.

A preparation method of an alumina ceramic valve core ceramic chip and a product thereof. The alumina ceramic valve core ceramic chip is obtained by the steps of mixing alumina, a sintering aid and a toughening agent according to a raw material ratio, ball-milling, drying, cold isostatic pressing, sintering and the like. The alumina ceramic valve core ceramic chip is prepared by adopting nano alumina and zirconium oxide as the sintering aid, so that the material has excellent bending strength, fracture toughness, hardness and low wear rate, the bending strength can reach 357.8-360.06 MPa, the fracture toughness is 4.32-4.56 MPa.sup.1/2, the Vickers hardness is 1592.7-1614.8 MPa. the wear rate is 0.04-0.09%, and the alumina ceramic valve core ceramic chip is an ideal material for preparing a faucet valve core.

A Li.sub.3Mg.sub.2SbO.sub.6-based microwave dielectric ceramic material easy to sinter and with high Q value, and a preparation method thereof are disclosed. A chemical formula of the material is Li.sub.3(Mg.sub.1-xZn.sub.x).sub.2SbO.sub.6, wherein 0.02≤x≤0.08. The preparation method includes: 1) mixing and ball-milling Sb.sub.2O.sub.3 and Li.sub.2CO.sub.3 according to a chemical ratio and then drying, and conducting pre-sintering to obtain a Li.sub.3SbO.sub.4 phase; and 2) mixing and ball-milling MgO, ZnO and Li.sub.3SbO.sub.4 powder according a chemical ratio of Li.sub.3(Mg.sub.1-xZn.sub.x).sub.2SbO.sub.6 and then drying, conducting granulation and sieving after adding an adhesive, pressing into a cylindrical body, and sintering the cylindrical body into ceramic in the air at 1325° C. and under normal pressure, wherein a dielectric constant is 7.2-8.5, a quality factor is 51844-97719 GHz, and a temperature coefficient of resonance frequency is −14-1 ppm/° C.

Provided is a three-dimensional object producing method for producing a three-dimensional object using primary particles containing at least a ceramic material, the three-dimensional object producing method including: a forming step of forming a layer using secondary particles containing the primary particles and a binder resin; and an applying step of applying a liquid for dissolving the binder resin to the layer formed in the forming step, wherein a central particle diameter of the primary particles is 5 micrometers or less.