An electro-conductive B.sub.4C—TiB.sub.2 has a microstructure in which large B.sub.4C grains are coated by small TiB.sub.2 grains. The composite ceramic includes 10˜30% by volume of TiB.sub.2. A method for preparing the electro-conductive B.sub.4C—TiB.sub.2 composite ceramic includes: (1) weighing B.sub.4C, TiC, and amorphous B powder; (2) mixing evenly and drying thoroughly the powders; and (3) loading the mixed powder into a graphite mold; and placing the graphite mold in a spark plasma sintering furnace for sintering under vacuum, where the sintering is performed at 2000° C. and 50 MPa for 5˜20 min.

Particles of a refractory metal or a refractory-metal compound capable of decomposing or reacting into refractory-metal nanoparticles, elemental silicon, and an organic compound having a char yield of at least 60% by weight are combined to form a precursor mixture. The mixture is heating, forming a thermoset and/or metal nanoparticles. Further heating form a composition having nanoparticles of a refractory-metal silicide and a carbonaceous matrix. The composition is not in the form of a powder

A cBN-based ultra-high pressure sintered body contains cBN particles and a binder phase. The binder phase contains at least one of a nitride or oxide of Al or a nitride, carbide, or carbonitride of Ti, and a metal boride having an average particle diameter of 20 to 300 nm is dispersed in an amount of 0.1 to 5.0 vol % in the binder phase. The metal boride includes a metal boride (B) containing at least one of Nb, Ta, Cr, Mo, and W as a metal component and containing no Ti and a metal boride (A) containing only Ti as a metal component. In a case where a ratio (vol %) of the metal boride (A) in the metal boride is represented by V.sub.a and a ratio (vol %) of the metal boride (B) is represented by V.sub.b, a ratio of V.sub.b/V.sub.a is 0.1 to 1.0.

The invention relates to nickel-coated hexagonal boron nitride nanosheet composite powder, its preparation and high-performance composite ceramic cutting tool material. The composite powder has a core-shell structure with BNNS as the core and Ni as the shell. The self-lubricating ceramic cutting tool material is prepared by wet ball milling mixing and vacuum hot-pressing sintering with a phase alumina as the matrix, tungsten-titanium carbide as the reinforcing phase, nickel-coated hexagonal boron nitride nanosheet composite powder as the solid lubricant and magnesium oxide and yttrium oxide as the sintering aids. The invention also provides preparation methods of the nickel-coated hexagonal boron nitride nanosheet composite powder and the self-lubricating ceramic cutting tool material.

A crack self-healing functionally gradient material for ceramic cutting tools and a preparation method thereof. The material for ceramic cutting tools has a symmetrical gradient structure, and based on the percentage by mass, components of each layer include 50%-80% of Ti(C.sub.7,N.sub.3), 25%-5% of (W.sub.7,Ti.sub.3)C and 20%-0% of TiSi.sub.2; contents of components of layers that are symmetrical relative to a central layer are the same and a thickness is symmetrically distributed; a content of Ti(C.sub.7,N.sub.3) gradually increases from the surface layer to the central layer, contents of (W.sub.7,Ti.sub.3)C and Ti Si.sub.2 gradually decrease by 5% from the surface layer to the central layer, and the contents of Ni and Mo gradually increase from the surface layer to the central layer.

A film is formed by use of a composition containing (A) a binder resin, (B) a hard particle, and (C) a solid lubricant selected from the group containing molybdenum disulfide and graphite, wherein the composition contains tungsten carbide as the hard particle, and wherein weight ratio of (B) the hard particles and (C) the solid lubricant, (B)/(C), is in the range of 1 to 3.

A process of forming a Si-containing ceramic comprises forming a Si-based polymeric composition. The process includes neutralizing a charge of said Si-based polymeric composition. The process includes adding thermal energy under a controlled atmosphere to the Si-based polymeric composition. A turbine engine component comprises an airfoil and the airfoil comprises a Ceramic Matrix Composite (CMC) material.

The present invention relates to a process for preparing a composite, ultra-refractory, fibre-reinforced ceramic material obtained through the infiltration of carbon and/or silicon carbide fibres with a ceramic suspension comprising yttrium, lanthanum and/or scandium compounds, and the subsequent densification of the composite. The fibre-reinforced UHTC compounds obtained by the process can be used for making items intended for use in extreme temperature and pressure conditions.

The invention relates to an item made of a material consisting of a plurality of ceramic phases, said material including: a majority ceramic phase comprising nitrides and/or carbonitrides of one or more element(s) selected from among Ti, Zr, Hf, V, Nb, and Ta, said majority ceramic phase being present in a percentage by weight comprised between 60 and 98%, at least one minority ceramic phase, with either one single minority ceramic phase formed of zirconium and/or aluminium silicide, or several minority ceramic phases formed respectively of carbides of one or more element(s) selected from among Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W and of zirconium oxides and/or aluminium oxides, said at least one minority ceramic phase being present in its entirety in a percentage by weight comprised between 2 and 40%.

The present invention also relates to the method for manufacturing this item.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer, an organically modified silicon dioxide preceramic polymer, and, optionally, at least one filler. The preceramic resin formulation is formulated to exhibit a viscosity of from about 1,000 cP at about 25° C. to about 5,000 cP at a temperature of about 25° C. The at least one filler comprises first particles having an average mean diameter of less than about 1.0 μm and second particles having an average mean diameter of from about 1.5 μm to about 5 μm. Impregnated fibers comprising the preceramic resin formulation are also disclosed, as is a composite material comprising a reaction product of the polycarbosilane preceramic polymer, organically modified silicon dioxide preceramic polymer, and the at least one filler. Methods of forming a ceramic matrix composite are also disclosed.