A refractory object may include a zircon body that is intentionally doped with a dopant including an alkaline earth element and aluminum. The refractory object can have an improved creep deformation rate. In an embodiment, the refractory object can have a creep deformation rate of not greater than about 1.8 E-5 h.sup.−1 at a temperature of 1350° C. and a stress of 2 MPa. In another embodiment, the zircon body may include an amorphous phase including an alkaline earth metal element.

A piezoelectric material composition, a method of manufacturing the same, a piezoelectric device, and apparatus including the piezoelectric device. The piezoelectric device may include a piezoelectric device layer including a first material and a second material surrounded by the first material, a first electrode portion disposed at a first surface of the piezoelectric device layer, and a second electrode portion disposed at a second surface of the piezoelectric device layer opposite to the first surface, wherein the piezoelectric device layer comprises a piezoelectric material composition represented by Chemical Formula 1: 0.96(Na.sub.aK.sub.1-a)(Nb.sub.b(T.sub.1-b))O.sub.3-(0.04-x)MZrO.sub.3-x(Bi.sub.cAg.sub.1-c)ZrO.sub.3+d mol % NaNbO.sub.3, wherein T is Sb or Ta, M is Sr, Ba or Ca, a is 0.4≤a≤0.6, b is 0.90≤b≤0.98, c is 0.4≤c≤0.6, d is 0≤d≤5.0, and x is 0≤x≤0.04 and wherein T is Sb or Ta and M is Sr, Ba, or Ca.

The present invention provides a high alumina fused cast refractory that is easily produced and has low porosity and high corrosion resistance, and a method of producing the same. The high alumina fused cast refractory of the present invention has the following chemical composition: 95.0 mass % to 99.5 mass % Al.sub.2O.sub.3, 0.20 mass % to 1.50 mass % SiO.sub.2, 0.05 mass % to 1.50 mass % B.sub.2O.sub.3, 0.05 mass % to 1.20 mass % MgO and balance. The method of producing the high alumina fused cast refractory of the present invention includes obtaining a mixture by mixing an Al.sub.2O.sub.3 source material, a SiO.sub.2 source material, a B.sub.2O.sub.3 source material and an MgO source material, and fusing the mixture.

A ceramic composite and a method of preparing the same are provided. The method of preparing the ceramic composite includes mixing an aluminum slag and a carbon accelerator to obtain a mixture and reacting the mixture at a temperature equal to or greater than 1600° C. in a nitrogen atmosphere to obtain a ceramic composite. The aluminum slag includes aluminum, oxygen, nitrogen, and magnesium. The weight ratio of the oxygen to the aluminum is 0.6 to 2. The weight ratio of the nitrogen to the aluminum is 0.1 to 1.2. The weight ratio of the magnesium to the aluminum is 0.04 to 0.2. The ceramic composite includes aluminum nitride accounting for at least 90 wt % of the ceramic composite.

The invention relates to a method for producing a non-oxide ceramic powder comprising a nitride, a carbide, a boride or at least one MAX phase with the general composition Mn+1AXn, where M=at least one element from the group of transition elements (Sc, Ti, V, Cr, Zr, Nb, Mo, Hf and Ta), A=at least one A group element from the group (Si, Al, Ga, Ge, As, Cd, In, Sn, Tl and Pb), X=carbon (C) and/or nitrogen (N) and/or boron (B), and n=1, 2 or 3. According to the invention, corresponding quantities of elementary starting materials or other precursors are mixed with at least one metal halide salt (NZ), compressed (pellet), and heated for synthesis with a metal halide salt (NZ). The compressed pellet is first enveloped with another metal halide salt, compressed again, arranged in a salt bath and heated therewith until the melting temperature of the salt is exceeded. Optionally, melted silicate can be added, which prevents the salt from evaporating at high temperatures. Advantageously, the method can be carried out in the presence of air.

An alumina-ceramic-based electrical insulator, to a method for producing the insulator, and to a vacuum tube includes the insulator. The electrical insulator is for insulating two electrodes of a vacuum tube through which a charged particle beam flows, the electrical insulator being formed of an alumina-based ceramic. The ceramic comprises a vitreous phase of between 2% and 8% by weight into which at least one metal oxide is diffused from a face of the electrical insulator.

The present invention relates to a ceramic, to a process for preparing the ceramic and to the use of the ceramic as a dielectric in a capacitor.

A method of making abrasive particles includes: providing a slurry comprising non-colloidal solid particles and a liquid vehicle; forming at least a portion of the slurry into shaped bodies contacting a substrate; at least partially drying the shaped bodies to provide shaped abrasive precursor particles; separating at least a portion of the shaped abrasive precursor particles from the substrate; and converting at least a portion of the shaped abrasive precursor particles into shaped abrasive particles. The shaped abrasive particles comprise alpha alumina having an average crystal grain size of 0.8 to 8 microns and an apparent density that is at least 92 percent of the true density. Each shaped abrasive particle has a respective surface comprising a plurality of smooth sides that form at least four vertexes. Shaped abrasive particles, abrasive articles including them, and methods of using are also disclosed.

A piezoelectric thin film 3 contains a metal oxide, the metal oxide contains bismuth, potassium, titanium, iron and element M, the element M is at least one of magnesium and nickel, at least a part of the metal oxide is a crystal having a perovskite structure, and a (001) plane, a (110) plane or a (111) plane of the crystal is oriented in a normal direction dn of the surface of the piezoelectric thin film 3.

A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 having a hexagonal structure, two-crystal grain boundaries 6a formed between two of the M-type ferrite crystal grains 4, and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. This ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains B in an amount of 0.005 to 0.9 mass % in terms of B.sub.2O.sub.3, the two-crystal grain boundaries 6a and the multiple-crystal grain boundaries 6b contain Si and Ca, and in a cross-section parallel to a c-axis of the ferrite sintered magnet, when the number of multiple-crystal grain boundaries 6b having a maximum length of 0.49 to 5 μm per cross-sectional area of 76 μm.sup.2 is N, N is 7 or less.