The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiTa.sub.2O.sub.6-based microwave dielectric ceramic material co-sintered at low temperature and its preparation method. Based on the low melting point characteristics of CuO and B.sub.2O.sub.3, and the radius of Cu.sup.2+ ions is similar to that of Ni.sup.2+ and Ta.sup.5+ ions, the chemical general formula of the invention is designed as xCuO-(1-x)NiO-[7.42y+(xy/14.33)]B.sub.2O.sub.3—Ta.sub.2O.sub.5, and the molar content of each component is adjusted from raw materials. The main crystalline phase of NiTa.sub.2O.sub.6 is synthesized at a lower pre-sintering temperature, and NiTa.sub.2O.sub.6-based ceramic material with low-temperature sintering characteristics and excellent microwave dielectric properties are directly synthesized at one time, which broadened the application range in LTCC field.

The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiTa.sub.2O.sub.6-based microwave dielectric ceramic material co-sintered at low temperature and its preparation method. Based on the low melting point characteristics of CuO and B.sub.2O.sub.3, and the radius of Cu.sup.2+ ions is similar to that of Ni.sup.2+ and Ta.sup.5+ ions, the chemical general formula of the invention is designed as xCuO-(1-x)NiO-[7.42y+(xy/14.33)]B.sub.2O.sub.3—Ta.sub.2O.sub.5, and the molar content of each component is adjusted from raw materials. The main crystalline phase of NiTa.sub.2O.sub.6 is synthesized at a lower pre-sintering temperature, and NiTa.sub.2O.sub.6-based ceramic material with low-temperature sintering characteristics and excellent microwave dielectric properties are directly synthesized at one time, which broadened the application range in LTCC field.

Disclosed herein are compounds, methods, and tools which comprise composite matrices of tungsten tetraborides and ceramics.

Disclosed herein are compounds, methods, and tools which comprise composite matrices of tungsten tetraborides and ceramics.

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.

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.

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.

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.

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.