A dielectric composition including a complex oxide containing bismuth, zinc, and niobium, includes a crystal phase formed of the complex oxide and having a pyrochlore type crystal structure, and an amorphous phase. When the complex oxide is represented by a composition formula Bi.sub.xZn.sub.yNb.sub.zO.sub.1.75+, in which x, y, and z satisfy relations of x+y+z=1.00, 0.20y0.50, and 2/3x/z3/2.

An aluminum nitride plate satisfies both of a relation 1: c1>97.5% and a relation 2: c2/c1<0.995 where c1 is a c-plane degree of orientation that is defined as a ratio of a diffraction intensity of (002) plane to a sum of the diffraction intensity of (002) plane and a diffraction intensity of (100) plane when the surface layer of the aluminum nitride plate is subjected to an X-ray diffraction measurement, and c2 is a c-plane degree of (002) plane to the sum of the diffraction intensity of (002) plane and the diffraction intensity of (100) plane when a portion other than the surface layer of the aluminum nitride plate is subjected to the X-ray diffraction. Moreover, in the aluminum nitride plate, a difference in nitrogen content between the surface layer and the portion other than the surface layer is less than 0.15% in weight ratio.

An aluminum nitride plate satisfies a c1>97.5%, a c2>97.0%, a w1<2.5 degrees, and a w1/w2<0.995 where c1 is a c-plane degree of orientation that is defined as a ratio of a diffraction intensity of (002) plane when a surface layer of the aluminum nitride plate is subjected to an X-ray diffraction measurement, and c2 is a c-plane degree of orientation that is defined as a ratio of the diffraction intensity of (002) plane when a portion other than the surface layer of the aluminum nitride plate is subjected to the X-ray diffraction measurement, wherein w1 is a half-value width in an X-ray rocking curve profile of (102) plane of the surface layer and w2 is a half-value width in the X-ray rocking curve profile of (102) plane of the portion other than the surface layer.

A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.

In one aspect, composite carbide compositions are described herein which can facilitate the efficient and/or economical manufacture of articles comprising SiC. Briefly, a composite carbide composition comprises silicon carbide (SiC) particles and a silica interparticle phase covalently bonded to the SiC particles.

A transparent ceramic material is manufactured by molding a source powder into a compact, the source powder comprising a rare earth oxide consisting of at least 40 mol % of terbium oxide and the balance of another rare earth oxide, and a sintering aid, sintering the compact at a temperature T (1,300 C.T1,650 C.) by heating from room temperature to T1 (1200 C.T1T) at a rate of at least 100 C./h, and optionally heating from T1 at a rate of 1-95 C./h, and HIP treating the sintered compact at 1,300-1,650 C. The ceramic material has improved diffuse transmittance in the visible region and functions as a magneto-optical part in a broad visible to NIR region.

A method of treating at least one silicon carbide fibre, the method including a) formation of a silica layer at the surface of a silicon carbide fibre having an oxygen content less than or equal to 1% in atomic percentage, the silica layer being formed by contacting this fibre with an oxidizing medium having a temperature greater than or equal to 50 C. and pressure greater than or equal to 1 MPa, and b) removal of the silica layer formed by hydrothermal treatment of the fibre obtained after implementation of step a) in which the fibre is treated with water at a pressure between saturating vapour pressure and 30 MPa and at a temperature less than or equal to 400 C.

A method for forming an ultra-high temperature (UHT) composite structure includes dispensing a polymeric precursor with a spinneret biased at a first DC voltage; forming a plurality of nanofibers from the polymeric precursor; receiving the plurality of nanofibers with a collector biased at a second DC voltage different than the first DC voltage; and changing a direction of movement of the plurality of nanofibers between the spinneret and the collector with a plurality of magnets having a magnetic field by adjusting the magnetic field.

The present application discloses a method for fabricating a ceramic heating body with a porous heating film, which relates to technical field of fabricating method of heating body; the method including mixing, ball-milling, defoaming, molding and drying, sintering, paraffin filling, machining, coating, metalizing sintering, and electrode leading; the beneficial effects of the present application is simple in whole fabricating method, and by using a box furnace to sinter the green body under an oxidizing atmosphere and normal pressure, the fabricated ceramic heating body is heated uniformly and the heating efficiency is high.

The present invention provides titanium nitride-reinforced zirconia toughened alumina (ZTA) ceramic powder and a preparation method thereof, and belongs to the technical field of ceramic materials. The preparation method provided in the present invention includes the following steps: mixing an aluminum salt, a zirconium salt, a yttrium salt, and a titanium salt with water to obtain a mixed aqueous solution, where the aluminum salt, the zirconium salt, the yttrium salt, and the titanium salt are water-soluble inorganic salts; mixing the obtained mixed aqueous solution and an alkaline precipitant for precipitation, to obtain hydroxide precipitate powder; successively conducting first calcination and second calcination on the obtained hydroxide precipitate powder, to obtain oxide solid solution powder; and subjecting the obtained oxide solid solution powder to selective nitridation reaction, to obtain titanium nitride-reinforced ZTA ceramic powder.