Methods for fabricating refractory metal scandate nanocomposite powders with homogeneous microstructured refractory metal grains and a uniform nanosized dispersion of scandia are provided. The powders prepared by the sol-gel methods have a spherical morphology, a narrow distribution of particle sizes and a very uniform dispersion of nanosized scandia particles joined to the tungsten grains. The powder particle sizes can range from nanometers to micrometers. The powders can be pressed into porous cathode structures that can be impregnated with emissive materials to produce high current density and long life cathodes for high-power terahertz vacuum electron devices. The sol-gel fabrication methods allow control over the materials, particle size, particle composition and pore size and distribution of the cathode structure by manipulation of the process parameters.

Disclosed are embodiments of a barium magnesium tantalate including additional components to increase the Q value of the material. In some embodiments, complex tungsten oxides and/or hexagonal perovskite crystal structures can be added into the barium magnesium tantalate to provide for advantageous properties. In some embodiments, no tin is used in the formation of the material.

An abrasive article, comprising a polycrystalline material comprising abrasive grains and a filler material having an average negative coefficient of thermal expansion (CTE) within a range of temperatures between about 70 K to about 1500 K. A method of forming an abrasive article, comprising preparing an abrasive material, preparing a filler material having an average negative coefficient of thermal expansion (CTE) within a range of temperatures between about 150 K to about 1500 K, and forming a polycrystalline material comprising grains of the abrasive material and the filler material.

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.

Disclosed are embodiments of making a barium magnesium tantalate. The method can include providing barium magnesium tantalate and incorporating one of Ba.sub.2MgWO.sub.6, Ba.sub.8LiTa.sub.5WO.sub.24, Ba.sub.8LiTa.sub.5WO.sub.24, Ba.sub.2MgWO.sub.6, Ba.sub.3LaTa.sub.3O.sub.12, Ba.sub.8LiTa.sub.5WO.sub.24, BaLaLiWO.sub.6, Ba.sub.4Ta.sub.2WO.sub.12, Ba.sub.2La.sub.2MgW.sub.2O.sub.12, BaLaLiWO.sub.6, Sr.sub.3LaTa.sub.3O.sub.12, and SrLaTaO.sub.12 into the barium magnesium tantalate to form a solid solution having a high Q value.

A ceramic material, including: BaWO.sub.4-xM.sub.2CO.sub.3-yBaO-zB.sub.2O.sub.3-wSiO.sup.2, where x=0-0.2 mole, y=0-0.05 mole, z=0-0.2 mole, w=0-0.1 mole, M represents an alkali metal ion selected from Li.sup.+, K.sup.+, Na.sup.+, and x, y, z, and w are not zero at the same time.

Disclosed are embodiments of high Q modified materials. In some embodiments, complex tungsten oxides and/or hexagonal perovskite crystal structures can be added to provide for advantageous properties. In some embodiments, no tin is used in the formation of the material.

The present invention relates to a ceramic material for a multilayer capacitor. The ceramic material has a composition according to the following general formula:

Pb.sub.(y−1.5a−0.5b+c+0.5d−0.5e−f)Ca.sub.aA.sub.b(Zr.sub.1−xTi.sub.x).sub.(1−c−d−e−d)E.sub.cFe.sub.dNb.sub.eW.sub.fO.sub.3,

where
A is one or more of the group of Na, K and Ag;
E is one or more of the group of Cu, Ni, Hf, Si and Mn; and
0<a<0.14,
0.05≤x≤0.3,
0≤b≤0.12,
0<c≤0.12,
0≤d≤0.12,
0≤e≤0.12,
0≤f≤0.12,
0.9≤y≤1.5 and
0.001<b+c+d+e+f
applies.

Further, the invention includes a capacitor comprising the described ceramic material.

Disclosed herein are embodiments of low temperature co-fireable scheelite materials which can be used in combination with high dielectric materials, such as nickel zinc ferrite, to form composite structures, in particular for isolators and circulators for radiofrequency components. In some embodiments, the scheelite material can include aluminum oxide for temperature expansion regulation.

Disclosed herein are embodiments of low temperature co-fireable barium tungstate materials which can be used in combination with high dielectric materials, such as nickel zinc ferrite, to form composite structures, in particular for isolators and circulators for radiofrequency components. Embodiments of the material can include flux, such as bismuth vanadate, to reduce co-firing temperatures.