Isopipes (13) for making glass sheets using a fusion process are provided. The isopipes are made from alumina materials which have low levels of the elements of group IVB of the periodic chart, i.e., Ti, Zr, and Hf, as well as low levels of Sn. In this way, the alumina isopipes can be used with glasses that contain tin (e.g., as a fining agent or as the result of the use of tin electrodes for electrical heating of molten glass) without generating unacceptable levels of tin-containing defects in the glass sheets, specifically, at the sheets' fusion lines. The alumina isopipes disclosed herein are especially beneficial when used with tin-containing glasses that exhibit low tin solubility, e.g., glasses that have (RO+R.sub.2O)/Al.sub.2O.sub.3 ratios between 0.9 and 1.1, where, in mole percent on an oxide basis, (RO+R.sub.2O) is the sum of the concentrations of the glass' alkaline earth and alkali metal oxides and Al.sub.2O.sub.3 is the glass' alumina concentration.

A multilayer ceramic capacitor includes a ceramic body including dielectric layers and first and second internal electrodes disposed to face each other with respective dielectric layers interposed therebetween; and first and second external electrodes disposed on outer surfaces of the ceramic body, wherein the dielectric layer contains zirconium (Zr), a Zr content is 2×Zr/(Ba+Ca+Ti+Zr) based on an atomic ratio, a first crystal grain is composed of a core part having a Zr content of 3.0 at % or less and a shell part having a Zr content of 4.0 to 15.0 at %, and a number fraction of the first crystal grain to all crystal grains in the dielectric layer is 4% or more.

A refractory, coarse ceramic product including at least one granular refractory material, has an open porosity of between 22 and 45 vol.-%, in particular of between 23 and 29 vol.-%, and a grain structure of the refractory material, wherein the medium grain size fraction with grain sizes of between 0.1 and 0.5 mm is 10 to 55 wt.-%, in particular 35 to 50 wt.-%, and wherein the remainder of the grain structure is a finest grain fraction with grain sizes of up to 0.1 mm and/or coarse-grain fraction with grain sizes of more than 0.5 mm.

The invention relates to a method for the preparation of a blank of a ceramic material, wherein a first ceramic material and then a second ceramic material of different compositions are filled into a die and wherein the materials are pressed and after pressing are sintered. A layer of the first ceramic material is thereby filled into the die and a first cavity formed in the layer, the second ceramic material is then filled into the first open cavity and the materials pressed together and then heat-treated.

A silicon nitride ceramic material for a mobile phone rear cover and a preparation method therefor. The method comprises: using a mixture of a silicon source, a colorant, and a sintering aid as raw materials, mixing the raw material components, and performing shaping and sintering to obtain the silicon nitride ceramic material. The toughness of the silicon nitride ceramic material can reach more than 12 MPa.Math.m.sup.1/2; the thermal conductivity thereof can reach 40 to 70 W/m.Math.K; and a dielectric loss thereof is 10.sup.−4.

A refractory article can include a body including a content of alumina of at least 60 wt %, a content of silica of not greater than 20 wt %, a content of zirconia of not greater than 20 wt % for a total weight of the body. In a particular embodiment, the body includes a third phase including composite grains including mullite and zirconia. The third phase including the composite grains can be present within a range including at least 1 wt % and not greater than 35 wt % for a total weight of the body.

The present invention discloses a dielectric ceramic formula enabling one to obtain a multilayer ceramic capacitor by alternatively stacking the ceramic dielectric layers and base metal internal electrodes. The dielectric ceramic composition comprises a primary ingredient:

[(Na.sub.1-xK.sub.x).sub.sA.sub.1-s].sub.m[(Nb.sub.1-yTa.sub.y).sub.uB1.sub.vB2.sub.w)]O.sub.3

wherein:
A is at least one selected from the alkaline-earth element group of Mg, Ca, Sr, and Ba;
B1 is at least one selected from the group of Ti, Zr, Hf and Sn;
B2 is at least one selected from transition metal elements;
and wherein:
x, y, s, u, v, and w are molar fractions of respective elements, and m is the molar ratio of [(Na.sub.1-xK.sub.x).sub.sA.sub.1-s] and [(Nb.sub.1-yTa.sub.y).sub.uB1.sub.vB2.sub.w)]. They are in the following respective range:
0.93≤m≤1.07;
0.7≤s≤1.0;
0.00≤x≤0.05; 0.00≤y≤0.65;
0.7≤u≤1.0; 0.0≤v≤0.3; 0.001≤w≤0.100;
a first sub-component composes of at least one selected from the rare-earth compound,
wherein the rare-earth element is no more than 10 mol % parts with respect to the main component; and
a second sub-component composes a compound with low melting temperature to assist the ceramic sintering process, said frit, which is Li free and could be at least one selected from fluorides, silicates, borides, and oxides. The content of frit is within the range of 0.01 mol % to 15.00 mol % parts with respect to the main component.

A process of manufacturing a chromium alloyed molybdenum silicide portion of a heating element comprising the steps of: forming a mixture of a chromium powder and a silicon powder; reacting the mixture to a reaction product in an inert atmosphere at a temperature of at least 1100° C. but not more than 1580° C.; converting the reaction product to a powder comprising CrSi.sub.2; forming a powder ceramic composition by mixing the powder comprising CrSi.sub.2 with a MoSi.sub.2 powder and optionally with an extrusion aid; forming the portion of the heating element; and sintering the portion of the heating element in a temperature of from about 1450° C. to about 1700° C.; characterized in that the chromium powder and the silicon powder are provided separately to the mixture.

The invention relates to a coloured zirconia ceramic dental mill blank having fluorescing properties, processes of production such a mill blank and uses thereof, in particular for producing zirconia ceramic dental restorations.

The dental mill blank having a shape allowing the dental mill blank to be attached or fixed to a machining device, the dental mill blank comprising a porous zirconia material, the porous zirconia material comprising the oxides Zr oxide calculated as ZrO.sub.2: from about 80 to about 97 wt.-%, Al oxide calculated as Al.sub.2O.sub.3: from about 0 to about 0.15 wt.-%, Y oxide calculated as Y.sub.2O.sub.3: from about 1 to about 10 wt.-%, Bi oxide calculated as Bi.sub.2O.sub.3: from about 0.01 to about 0.20 wt.-%, Tb oxide calculated as Tb.sub.2O.sub.3: from about 0.01 to about 0.8 wt.-%, and optionally one or two of the following oxides: Er oxide calculated as Er.sub.2O.sub.3: from about 0.01 to about 3.0 wt.-%, Mn oxide calculated as MnO.sub.2: from about 0.0001 to about 0.08 wt.-%, wt.-% with respect to the weight of the porous zirconia material.

A dielectric ceramic composition and a multilayer ceramic capacitor comprising the same includes a barium titanate (BaTiO.sub.3)-based base material main ingredient and an accessory ingredient, and the accessory ingredient includes a third trivalent lanthanide rare earth element A and terbium (Tb) as rare earth elements, and a molar ratio (Tb/A) of a content of terbium (Tb) to the content of the trivalent lanthanide rare earth element A satisfies 0.15≤Tb/A<0.50.