A process for the manufacture of a refractory block including more than 80% zirconia, in percentage by weight based on the oxides. The process includes the following successive stages: melting, under reducing conditions, of a charge including more than 50% zircon, in percentage by weight, such as to reduce the zircon and obtain a molten material, application of oxidizing conditions to the molten material, casting of the molten material, and cooling until at least partial solidification of the molten material in the form of a block. Also, the process can include heat treatment of the block.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

A method for making ceramic composites via sintering a mixture of alumina and oil fly ash. The alumina is in the form of nanoparticles and/or microparticles. The oil fly ash may be treated with an acid prior to the sintering. The composite may comprise graphite carbon derived from oil fly ash dispersed in an alumina matrix. The density, mechanical performance (e.g. Vickers hardness, fracture toughness), and thermal properties (e.g. thermal expansion, thermal conductivity) of the ceramic composites prepared by the method are also specified.

A Cr—Si sintered body contains Cr and Si. The Cr—Si sintered body contains a crystalline CrSi.sub.2 phase and a crystalline Si phase. A content of the Si phase in the Cr—Si sintered body is 40% by mass or more. A relative density of the Cr—Si sintered body relative to a true density of the Cr—Si sintered body is 95% or more. The CrSi.sub.2 phase has an average crystal grain size of 40 μm or less, and the Si phase has an average crystal grain size of 30 μm or less. A total content of impurities in the Cr—Si sintered body is 200 ppm by mass or less, and the impurities are composed of at least one element selected from the group consisting of Mn, Fe, Mg, Ca, Sr, and Ba.

The present invention relates to inorganic fibres having a composition comprising: 61.0 to 70.8 wt % SiO.sub.2; 28.0 to 39.0 wt % CaO; 0.10 to 0.85 wt % MgO other components, if any, providing the balance up to 100 wt %,

The sum of SiO.sub.2 and CaO is greater than or equal to 98.8 wt % and the other components comprise less than 0.70 wt % Al.sub.2O.sub.3, if any.

A method for making a carbon carbon, carbon ceramic matrix, or carbon silica composite, comprising melt processing a resin comprising a polyaryletherketone (PAEK) and at least one reinforcing additive to make a precursor part, pyrolyzing the precursor part to make a pyrolyzed part, infusing a liquid second resin into the pyrolyzed part to make an infused part, and pyrolyzing the infused part. Other methods comprise processing aligned reinforcing additives and a resin comprising a PAEK to make an aligned reinforcing additives PAEK, aligned 1-2 dimensional flake material, or aligned 1-2 dimensional platelet material, to create a fabric, prepreg or tape comprising the aligned reinforcing additives and impregnated PAEK. Other methods comprise impregnating continuous fiber tape or fabric with a resin comprising PAEK and at least one reinforcing additive or co-weaving a continuous fiber or fabric with a PAEK fiber comprising PAEK and at least one reinforcing additive.

Described are cementitious reagent materials produced from globally abundant inorganic feedstocks. Also described are methods for the manufacture of such cementitious reagent materials and forming the reagent materials as microspheroidal glassy particles. Also described are apparatuses, systems and methods for the thermochemical production of glassy cementitious reagents with spheroidal morphology. The apparatuses, systems and methods make use of an in-flight melting/quenching technology such that solid particles are flown in suspension, melted in suspension, and then quenched in suspension. The cementitious reagents can be used in concrete to substantially reduce the CO.sub.2 emission associated with cement production.

The present disclosure relates to a magnesium-based raw material and a preparation method thereof. According to the technical solution, 40-60 wt % fused magnesia particles, 30-40 wt % fine monoclinic zirconia powder, 5-20 wt % fine zirconium oxychloride powder, 0.5-1.5 wt % calcium hydroxide nanopowder, 0.2-0.5 wt % calcium hydroxide nanopowder, and 0.1-0.3 wt % maleic acid are stirred for 15 min to mix well in a high-speed mixing mill at a constant temperature of 25° C. to obtain a mixed powder; and the mixed powder is mixed through a ball mill at a constant temperature of 25° C. for 3 min, roasted in a high temperature furnace at 250-400° C. for 0.5-3 h, and finally cooled to room temperature.

Embodiments are directed to the field of ceramics and relate to electron-emitting ceramics such as those which can be used as cathode material for electron emissions in space flight systems, for example. Embodiments specify an electron-emitting ceramic which has an improved temperature conductivity with a simultaneously continuous electron emission. The electron-emitting ceramic contains at least>70 vol. % C12A7 electride and a proportion of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, In, Sn, Sb, Te, Tl, Pb, or Bi as metal and/or with Ti, wherein the proportion of the metals lies between>0 and<30 vol. %, and the ceramic has a density of at least 85% of the theoretical density of the ceramic and the ceramic contains 0 to maximally 10 vol. % production-specific impurities.

Provided is a thermoelectric material satisfying (MX).sub.1+a(TX.sub.2).sub.n and having a superlattice structure, wherein M is at least one element selected from the group consisting of Group 13, Group 14, and Group 15, T is at least one element selected from Group 5, X is a chalcogenide element, a is a real number satisfying 0<a<1, and n is a natural number of 1 to 3.