The present invention relates to a method for preparing a phase-separated lead telluride-lead sulfide nanopowder using solution synthesis and a phase-separated lead telluride-lead sulfide nanopowder prepared by the method. The method includes: (a) mixing tellurium and a first solvent, followed by ultrasonic irradiation to prepare a tellurium precursor solution; (b) mixing an organosulfur compound and a second solvent, followed by ultrasonic irradiation to prepare a sulfur precursor solution; (c) mixing lead oxide, a third solvent, and a fourth solvent and heating the mixture to prepare a lead precursor solution; (d) adding the tellurium precursor solution to the lead precursor solution and allowing the mixture to react; (e) adding the sulfur precursor solution to the reaction mixture of step (d) and allowing the resulting mixture to react; and (f) cooling the reaction mixture of step (e) to room temperature to prepare a phase-separated lead telluride-lead sulfide nanopowder.

Disclosed is a chalcogenide material including germanium (Ge), selenium (Se), arsenic (As), silicon (Si) and indium (In). In the chalcogenide material, a content of selenium (Se) is 49 at % to 56 at %, a content of indium (In) is 1.1 at % or less, and a sum of contents of germanium (Ge) and silicon (Si) is 18 at % to 21 at %.

The present invention relates to a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries. The a nitrogen-doped sulfide-based solid electrolyte for all-solid batteries includes a compound with an argyrodite-type crystal structure represented by the following Formula 1:

Li.sub.aPS.sub.bN.sub.cX.sub.d[Formula 1] wherein 6a7, 3<b<6, 0<c1, 0<d2, and each X is the same or different halogen atom selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I).

The invention relates to a polycrystalline IR transparent material produced by sintering chalcogenide powder, e.g., ZnS powder, using hot uniaxial pressing followed by hot isostatic pressing. The microstructure of the material described in this disclosure is much finer than that found in material produced using the state of the art process. By using a powder with a particle size fine enough to improve sintering behavior but coarse enough to prevent a lowering of the wurtzite-sphalerite transition temperature, a highly transparent material with improved strength is created without degrading the optical properties. A high degree of transparency is achieved during hot pressing by applying pressure after the part has reached a desired temperature. This allows some degree of plastic deformation and prevents rapid grain growth which can entrap porosity. The crystallographic twins created during this process further inhibit grain growth during hot isostatic pressing.

A thermoelectric composite material includes MXene inserted at a boundary of a crystal grain consisting of a thermoelectric material. Accordingly, the thermoelectric composite material may have a reduced thermal conductivity and an increased electrical conductivity. Furthermore, a mechanical property of the thermoelectric composite material may be improved. Thus, the thermoelectric composite material may improve a thermoelectric ability of a thermoelectric module.

A sintered polycrystalline body and a method of forming the sintered polycrystalline body are disclosed. The sintered polycrystalline body comprises a plurality of particles cubic boron nitride dispersed in a matrix. The matrix includes materials selected from compounds of any of titanium and aluminium. The polycrystalline body further comprises 0.1 to 5.0 volume % of lubricating chalcogenide particles dispersed in the matrix. The chalcogenide particles have a coefficient of friction of less than 0.1 with respect to a workpiece material. Preferably sulfide particles are used as lubricant. Preferably 30-70 vol.-% cBN is contained. Sintering takes place at 1100-1600 C. and 4-8 GPa.

A complex proppant particle is made of a coal dust and binder composite that is pyrolyzed. Constituent portions of the composite react together causing the particles to increase in density and reduce in size during pyrolyzation, yielding a particle suitable for use as a proppant.

A method is provided for producing a pulverulent precursor material of the general formula M1.sub.xM2.sub.y(Si,Al).sub.12(O,N).sub.16 or M1.sub.2-zM2.sub.zSi.sub.8Al.sub.4N.sub.16 having the method steps A) producing a pulverulent mixture of starting materials, B) calcining the mixture under a protective gas atmosphere and subsequent grinding, wherein in method step A) at least one nitride with a specific surface area of greater than 2 m.sup.2/g is selected as starting material. A pulverulent precursor material and the use thereof are additionally provided.

A method of manufacturing a sulfide-based solid electrolyte through a wet process is provided. The method includes preparing a slurry by adding a solvent to a mixture including lithium sulfide and a sulfide of a group 14 or group 15 element and amorphizing the mixture by milling the slurry. The slurry is dried in order to remove the solvent. The dried mixture is crystallized by heat-treating to form the sulfide-based solid electrolyte.

A heat insulation material obtained by sintering a raw material comprising: 52 to 93 weight % of alumina particles having an average particle diameter of 100 nm or smaller, 1 to 45 weight % of one or more crystal transition suppression materials selected from silica particles, silica stone, talc, mullite, silicon nitride, silica fume, wollastonite, bentonite, kaolin, sepiolite and mica particles, 0 to 40 weight % of a radiation scattering material, and 1 to 20 weight % of fibers.