A dielectric composition is provided. The dielectric composition includes: a main component made of: a first complex oxide expressed by a chemical formula {K(Ba.sub.1-xSr.sub.x).sub.2Nb.sub.5O.sub.15}; and a second complex oxide expressed by a chemical formula that differs the chemical formula of the first complex oxide. The second complex oxide is a complex oxide expressed by one of chemical formulae: {(Ca.sub.1-ySr.sub.y)(Zr.sub.1-zTi.sub.z)O.sub.3}; {Ba(Ti.sub.1-uZr.sub.u)O.sub.3}; {(Ca.sub.1-vSr.sub.v)TiSiO.sub.5}; and {(Ba.sub.1-wRe.sub.2w/3)Nb.sub.2O.sub.6}, x satisfies 0.35≦x≦0.75, and a satisfies 0.25≦a≦0.75 when a molar ratio between the first and second complex oxides is defined by a:b in an order and a+b=1.00.

An alumina sintered body having a low dielectric loss tangent and a method for manufacturing the alumina sintered body are provided. An alumina sintered body contains Al.sub.2O.sub.3 99.50 mass % or more, and 99.95 mass % or less and sodium and silicon, wherein at a surface layer A in any given cross-section and a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer A is smaller than the concentration ratio of sodium to silicon at the central portion B.

Disclosed is a rapid, reproducible solution-based method to synthesize solid sodium ion-conductive materials. The method includes: (a) forming an aqueous mixture of (i) at least one sodium salt, and (ii) at least one metal oxide; (b) adding at least one phosphorous precursor as a neutralizing agent into the mixture; (c) concentrating the mixture to form a paste; (d) calcining or removing liquid from the paste to form a solid; and (e) sintering the solid at a high temperature to form a dense, non-porous, sodium ion-conductive material. Solid sodium ion-conductive materials have electrochemical applications, including use as solid electrolytes for batteries.

A process for manufacturing ceramic-metal composite material, comprises dissolving ceramic powder into water to obtain an aqueous solution of ceramic; mixing metal powder having a multimodal particle size where largest particle size is one fourth of the minimum dimension of a device, with the aqueous solution of ceramic to obtain a powder containing ceramic precipitated on the surface of metal particles; mixing the powder containing ceramic precipitated on the surface of the metal particles, with ceramic powder having a particle size below 50 μm, to obtain a powder mixture; adding saturated aqueous solution of ceramic to the powder mixture to obtain an aqueous composition containing ceramic and metal; compressing the aqueous composition to form a disc of ceramic-metal composite material containing ceramic and metal; and removing water from the ceramic-metal composite material; wherein ceramic content of the disc is 10 vol-% to 35 vol-%. Alternatively, ceramic-ceramic composite material may be manufactured.

A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

An antimicrobial material including a substrate and an antimicrobial mixed metal oxide, mixed metal sulfide, or mixed metal oxysulfide in and/or on the substrate is described, as well as antimicrobial coating materials and coatings formed therefrom. The antimicrobial material may be constituted in an antimicrobial surface of a surface-presenting substrate, to combat transmission and spread of microbial disease, e.g., disease mediated by microbial pathogens such as bacteria, viruses, and fungi. Antimicrobial mixed metal oxide, mixed metal sulfide, or mixed metal oxysulfide as described may be contacted with microorganisms to effect inactivation thereof.

The present disclosure provides a glass ceramic composite electrolyte comprising gadolinium doped ceria and glass composite with desired ionic conductivity in the temperature range of 400 to 600° C., suitable for applications in solid oxide fuel cells. Also disclosed is a process for the preparation of the glass ceramic composite electrolyte.

Disclosed is a (K,Na)NbO.sub.3 (abbreviated by “KNN”)-based single crystal ceramic. The KNN-based single crystal ceramic according to the present disclosure is formulated by (K.sub.0.5−x/2Na.sub.0.5−x/2−y□.sub.y/2M.sub.x+y/2)Nb.sub.1−x/3+yO.sub.3, wherein M indicates a metal having a different valence from Na, and □ indicates a metal vacancy. The above formulated KNN-based single crystal ceramic allows compensating for the volatilization of Na in a growing grain due to the addition of M.sup.2+ ions, and substituting M.sup.2+ ions for Na.sup.+ ions to form metal vacancies, thereby making possible the single crystal growth.

Provided are a barium titanate-based piezoelectric ceramics having satisfactory piezoelectric performance and a satisfactory mechanical quality factor (Q.sub.m), and a piezoelectric element using the same. Specifically provided are a piezoelectric ceramics, including: crystal particles; and a grain boundary between the crystal particles, in which the crystal particles each include barium titanate having a perovskite-type structure and manganese at 0.04% by mass or more and 0.20% by mass or less in terms of a metal with respect to the barium titanate, and the grain boundary includes at least one compound selected from the group consisting of Ba.sub.4Ti.sub.12O.sub.27 and Ba.sub.6Ti.sub.17O.sub.40, and a piezoelectric element using the same.

A solid ionic conducting material for use in an electrochemical device comprises an oxyhydroxide or hydrated oxide derived from of an oxide with a perovskite, Brownmillerite, layered oxide, and/or K.sub.4CdCl.sub.6 structure, the elemental composition of the initial oxide being selected to provide suitable conduction properties for the derived anhydrous or hydrated oxyhydroxide or hydrated oxide. A method of making such a solid ionic conducting material, including treatment with water, and an electrochemical device incorporating such a solid ionic conducting material (optionally as an electrolyte) are also disclosed.