An NTC compound, a thermistor and a method for producing a thermistor are disclosed. In an embodiment an NTC compound includes a ceramic material of a MnNiO system as a main constituent, wherein the MnNiO system has a general composition Ni.sub.xMn.sub.2O.sub.4-, wherein y corresponds to a molar fraction of Ni of a total metal content of the ceramic material of the MnNiO system, which is defined as c(Ni):(c(Ni)+c(Mn)), and wherein the following applies: 0.500<x<0.610 and 0.197<y<0.240.

The invention relates to a refractory product, a batch composition for producing said product, a method for producing the product and the use of the refractory product.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

The disclosed technology generally relates dielectric materials, and more particularly to a combination of co-fireable dielectric materials that can be attached to each other without the use of adhesives. In an aspect, a composite article comprises a magnetic portion comprising a nickel zinc ferrite. The composite article additionally comprises a non-magnetic portion contacting the magnetic portion, the non-magnetic portion comprising a spinel-structured oxide comprising Mg.sub.2-xAl.sub.2xTi.sub.1-xO.sub.4 and having a dielectric constant between about 7 and 14, wherein 0<x1.

A fused grain is essentially composed of a matrix of a magnesium aluminum oxide of MgAl.sub.2O.sub.4 spinel structure and/or of the MgOMgAl.sub.2O.sub.4 eutectic structure, and of inclusions essentially composed of magnesium oxide. The grain has the following overall chemical composition, as percentages by weight, expressed in the form of oxides: more than 5.0% and less than 19.9% of Al.sub.2O.sub.3, Al.sub.2O.sub.3 and MgO together represent more than 95.0% of the weight of the grain. The cumulative content of CaO and of ZrO.sub.2 is less than 4000 ppm, by weight.

A method of purifying a spinel powder includes contacting a spinel powder with an acid solution to form an acid-washed spinel composition and contacting the acid-washed spinel composition with a basic solution to form a purified composition. The purified powder is suited to formation of low-absorption shaped bodies, such as windows for high intensity laser devices.

Fused grains, in which the grains include a matrix of the zirconia-spinel eutectic coating inclusions composed essentially of a zirconia phase or of a spinel phase, the grains exhibit the following overall chemical composition, as percentages by weight expressed in the form of oxides: more than 45.0% and less than 95.0% of ZrO.sub.2, more than 3.0% and less than 40.0% of Al.sub.2O.sub.3, more than 1.0% and less than 20.0% of MgO, wherein ZrO.sub.2, Al.sub.2O.sub.3 and MgO together represent at least 95.0% of the weight of the grains.

Embodiments disclosed herein relate to using cobalt (Co) to fine tune the magnetic properties, such as permeability and magnetic loss, of nickel-zinc ferrites to improve the material performance in electronic applications. The method comprises replacing nickel (Ni) with sufficient Co.sup.+2 such that the relaxation peak associated with the Co.sup.+2 substitution and the relaxation peak associated with the nickel to zinc (Ni/Zn) ratio are into near coincidence. When the relaxation peaks overlap, the material permeability can be substantially maximized and magnetic loss substantially minimized. The resulting materials are useful and provide superior performance particularly for devices operating at the 13.56 MHz ISM band.

A method includes molding a raw material powder containing a ceramic powder and a thermoplastic resin having a glass transition temperature higher than room temperature into a shape by isostatic pressing and in which a raw material powder slurry is prepared by adding the ceramic powder and the thermoplastic resin to a solvent so that the thermoplastic resin is 2% by weight or more and 40% by weight or less with respect to a total weight of the ceramic powder and the thermoplastic resin, a cast-molded body is to formed by wet-casting the raw material powder slurry into a shape, dried, and subjected to first-stage isostatic press molding at a temperature lower than the glass transition temperature of the thermoplastic resin, then this first-stage press-molded body is heated to the glass transition temperature of the thermoplastic resin or above, and warm isostatic press (WIP) molding is performed.

The disclosed technology generally relates dielectric materials and methods of forming the same, and more particularly to a combination of co-fireable dielectric materials that can be attached to each other without the use of adhesives. In an aspect, a composite article comprises a magnetic portion comprising a nickel zinc ferrite. The composite article additionally comprises a non-magnetic portion contacting the magnetic portion, the non-magnetic portion comprising a spinel-structured oxide comprising Mg.sub.2-xAl.sub.2xTi.sub.1-xO.sub.4 and having a dielectric constant between about 7 and 14, wherein 0<x?1.