A transparent complex oxide sintered body is manufactured by sintering a compact in an inert atmosphere or vacuum, and HIP treating the sintered compact, provided that the compact is molded from a source powder based on a rare earth oxide: (Tb.sub.xY.sub.1-x).sub.2O.sub.3 wherein 0.4≤x≤0.6, and the compact, when heated in air from room temperature at a heating rate of 15° C./min, exhibits a weight gain of at least y % due to oxidative reaction, y being determined by the formula: y=2x+0.3. The sintered body has a long luminescent lifetime as a result of controlling the valence of Tb ion.

Provided is a cubic boron nitride sintered body including more than or equal to 85 volume percent and less than 100 volume percent of cubic boron nitride particles, and a remainder of a binder, wherein the binder contains WC, Co, and an Al compound, the binder contains W.sub.2Co.sub.21B.sub.6, and, when I.sub.A represents an X-ray diffraction intensity of a (111) plane of the cubic boron nitride particles, I.sub.B represents an X-ray diffraction intensity of a (100) plane of the WC, and I.sub.C represents an X-ray diffraction intensity of a (420) plane of the W.sub.2Co.sub.21B.sub.6, a ratio I.sub.C/I.sub.A of the I.sub.C to the I.sub.A is more than 0 and less than 0.10, and a ratio I.sub.C/I.sub.B of the I.sub.C to the I.sub.B is more than 0 and less than 0.40.

Methods and ceramic matrix composite articles formed thereby, as well as systems for making such ceramic matrix composite articles and carrying out such methods are disclosed herein. The methods include preparing a ceramic matrix composite by steps including (a) providing reinforcing fiber, such as carbon fiber, for impregnation; (b) heat treating the reinforcing fiber; (c) impregnating the heat treated reinforcing fiber with a composition comprising a ceramic forming polymer to form a fiber reinforced, ceramic forming polymer pre-preg; and (d) heat molding the fiber reinforced, ceramic forming polymer pre-preg to form a molded ceramic matrix composite article.

A cubic boron nitride sintered material includes: 20 to 80 volume % of cBN grains; and 20 to 80 volume % of a binder phase, wherein the binder phase includes first binder grains and second binder grains, in each of the first binder grains, a ratio of the number of atoms of the first metal element to a total of the number of atoms of the titanium and the number of atoms of the first metal element is more than or equal to 0.01% and less than 10%, in each of the second binder grains, this ratio is more than or equal to 10% and less than or equal to 80%, and in an X-ray diffraction spectrum of the cubic boron nitride sintered material, one or both of conditions 1 and 2 are satisfied.

Disclosed is a method for preparing an alumina-based solid solution ceramic powder by using an aluminum oxygen combustion synthesis water mist process, which comprises: drying raw materials and then mixing same until uniform to obtain a mixed material; loading the mixed material into a high-pressure reactor, igniting same in an oxygen-containing atmosphere, carrying out a high-temperature combustion synthesis reaction to form a high-temperature melt and then carrying out heat preservation for 1-60 s; and then opening a nozzle, ejecting the high-temperature melt through the nozzle and rapidly cooling same through a liquid phase, thus obtaining the alumina-based solid solution ceramic powder.

The present invention provides an Al.sub.2O.sub.3—ZrO.sub.2—Y.sub.2O.sub.3—TiN nanocomposite ceramic powder and a preparation method thereof, and belongs to the field of ceramic materials. In the ceramic powder provided by the present invention, a molar ratio of Zr:Al:Y:Ti is (30-70):(10-30):(0.4-1):(5-20). The nanocomposite ceramic powder provided by the present invention is good in dispersibility, and does not generate agglomeration, and the mechanical properties of a ceramic material obtained after sintering of the nanocomposite ceramic powder provided by the present invention are better. Proved by results of embodiments, the hardness of a ceramic material obtained by sintering of the nanocomposite ceramic powder provided by the present invention is 28-35 GPa, and abrasion ratio is 4500-6000:1.

High-purity gallium nitride particles having a low oxygen content suitable for a raw material or a sintered body is provided. Gallium nitride particles characterized in that the oxygen content is 0.5 at % or less and the total impurity amount of elements, Si, Ge, Sn, Pb, Be, Mg, Ca, Sr, Ba, Zn and Cd, is less than 10 wtppm are used.

The present disclosure provides for ceramic composite materials and methods of making ceramic composite materials. In an aspect, the ceramic composite materials can be made of polymer derived ceramics (PDCs) as the matrix, while substrates can be used as the microwave absorbing phases.

A process for producing a process for producing a LnM.sub.2Cu.sub.3O.sub.x high-temperature superconductive powder, the process comprising: i) providing an aqueous solution of Ln, M and Cu and at least one mineral acid; ii) adding at least one sequestrating agent and, optionally, at least one dispersant to the solution to form a precipitate; iii) recovering the precipitate from the solution; and iv) heating the precipitate in a flow of oxygen to form the LnM.sub.2Cu.sub.3O.sub.x powder, wherein Ln is a rare earth element, preferably Y, Ce, Dy, Er, Gd, La, Nd, Pr, Sm, Sc, Yb, or a mixture of two or more thereof, and wherein M is selected from Ca, Sr, and Ba.

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.