A piezoelectric material which is low in load on the environment, and also satisfies both the requirements of a high piezoelectric constant and a high mechanical quality factor. The piezoelectric material comprises a plurality of crystal grains containing Ba, Ca, Ti, Zr, Mn, and O. An average equivalent circle diameter of the crystal grains is not smaller than 1.0 μm and not larger than 10 μm. The crystal grains include crystal grains A each having a first domain with a width of not smaller than 300 nm and not larger than 800 nm, and crystal grains B each having a second domain with a width of not smaller than 20 nm and not larger than 50 nm.

The object of the present invention is to provide a large-sized gallium nitride-based sintered body having a small oxygen amount and high strength, a large-sized gallium nitride-based sintered body having a small oxygen amount and containing a dopant, to obtain a highly crystalline gallium nitride thin film which has become a n-type or p-type semiconductor by a dopant, and methods for producing them.

A gallium nitride-based sintered body, which has an oxygen content of at most 1 atm % and an average particle size (D50) of at least 1 μm and at most 150 μm.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

A ceramic article includes a ceramic matrix composite that has a porous reinforcement structure and a ceramic matrix within pores of the porous reinforcement structure. The ceramic matrix composite includes a surface zone comprised of an exterior surface of the ceramic matrix composite and pores that extend from the exterior surface into the ceramic matrix composite. A glaze material seals the surface zone within the pores of the surface zone and on the exterior surface of the surface zone as an exterior glaze layer on the ceramic matrix composite. The glaze material is a glass or glass-ceramic material. The ceramic matrix composite includes an interior zone under the surface zone, and the interior zone is free of any of the glaze material and has a greater porosity than the surface zone.

A sagger receiving element for burning powdery cathode materials for producing lithium ion accumulators including a rectangular shell comprising four side walls and a base, wherein the sagger receiving element is produced by a burning process from heat-resistant material which withstands temperatures of in particular more than 900° C., and wherein the material of the sagger receiving element is produced on the basis of oxide-bonded SiC, the material having the following chemical composition in percent by weight to a total of 100%: silicon carbide (SiC) content in a range of 40.0%-80.0%, Al.sub.2O.sub.3 content in a range of 10%-43%, total SiO.sub.2 content in a range of 5%-30%, and alkali oxide and iron oxide content of less than 2%.

The novel process enables designing of raw materials and processing parameters, enabling synergistic and simultaneous chemical reactions among the various reactants of the design mix of chemical precursor of brine sludge which includes barium sulphate, magnesium hydroxide, calcium carbonate, sodium chloride, silica, aluminum containing compounds necessary for developing highly efficient shielding phases leading to homogenous matrix of shielding materials.

One embodiment of the present invention provides a conductive ceramic composition comprising: conductive non-oxide ceramic particles; oxide ceramic particles electrostatically bonded or co-dispersed with the non-oxide ceramic particles; and a binder resin.

Disclosed is a method for making a ceramic matrix composite. The method includes infiltrating an initial ceramic matrix composite with a molten silicon infiltration material to form a silicon infiltrated composite; cooling the silicon infiltrated composite; heating a first portion of the cooled silicon infiltrated composite to a temperature in excess of the melt temperature of the silicon infiltration material in the presence of a carbon source; heating a second portion of the cooled silicon infiltrated composite to a temperature in excess of the melt temperature of the silicon infiltration material in the presence of a carbon source after heating the first portion; and cooling the heated portions to form a final ceramic matrix composite, wherein the first portion and second portion of the cooled silicon infiltrated composite are adjacent or overlap.

A preparation method and a product of a metal-matrix composite reinforced by nanoscale carbon materials are provided, including: plating metal layers on surfaces of the nanoscale carbon materials, and then adding mental particles to perform ball milling for dispersion and sintering. Volumes of the nanoscale carbon materials account for 0.01% to 30% of the metal-matrix composite. Size requirements of the nanoscale carbon materials and the metal particles are that: K×a sum of maximum cross-sectional areas of the nanoscale carbon materials in a unit volume ≤ a sum of surface areas of the mental particles in the unit volume; and the K represent a space compensation coefficient. The method is practical and effective, and the nanoscale carbon materials are efficiently and uniformly dispersed in metallic matrix. The obtained composite further has excellent mechanical, electrical and thermal properties, and is applied in metal-matrix composites, nano-electronic components, and bio sensors.

A thermoelectric conversion material made of a sintered body containing a magnesium silicide as a major component includes: a magnesium silicide phase; and a magnesium oxide layer formed on a surface layer of the magnesium silicide phase, in which an aluminum concentrated layer having an Al concentration higher than an aluminum concentration in an inside of the magnesium silicide phase is formed between the magnesium oxide layer and the magnesium silicide phase, and the aluminum concentrated layer has a metallic aluminum phase including aluminum or an aluminum alloy.