Disclosed are: damage-resistant ECMCs that need to work and remain elastic between minus 120° C. and positive 300° C.; ECMCs that need to be able to contain a flame of 1900° C. for more than 90 minutes; and composite structures, especially highly stressed structures. One of the characteristic problems of ceramic matrices is their fragility. Indeed, when a fracture starts, it propagates easily in the matrix. Disclosed are elastic ceramic matrix composites (ECMCs), for which: the ceramic matrix is split into solid “ceramic microdomains” (CMDs); the CMDs are connected to one another by a dense network of “elastic microelements” (EMEs); and the bonds between the EMEs and the CMDs are strong chemical bonds, preferably covalent.

Disclosed are: damage-resistant ECMCs that need to work and remain elastic between minus 120° C. and positive 300° C.; ECMCs that need to be able to contain a flame of 1900° C. for more than 90 minutes; and composite structures, especially highly stressed structures. One of the characteristic problems of ceramic matrices is their fragility. Indeed, when a fracture starts, it propagates easily in the matrix. Disclosed are elastic ceramic matrix composites (ECMCs), for which: the ceramic matrix is split into solid “ceramic microdomains” (CMDs); the CMDs are connected to one another by a dense network of “elastic microelements” (EMEs); and the bonds between the EMEs and the CMDs are strong chemical bonds, preferably covalent.

A process for manufacturing ceramic-metal composite material, comprises dissolving ceramic powder into water to obtain an aqueous solution of ceramic; mixing metal powder having a multimodal particle size where largest particle size is one fourth of the minimum dimension of a device, with the aqueous solution of ceramic to obtain a powder containing ceramic precipitated on the surface of metal particles; mixing the powder containing ceramic precipitated on the surface of the metal particles, with ceramic powder having a particle size below 50μ.Math.τ.Math., to obtain a powder mixture; adding saturated aqueous solution of ceramic to the powder mixture to obtain an aqueous composition containing ceramic and metal; compressing the aqueous composition to form a disc of ceramic-metal composite material containing ceramic and metal; and removing water from the ceramic-metal composite material; wherein ceramic content of the disc is 10 vol-% to 35 vol-%. Alternatively, ceramic-ceramic composite material may be manufactured.

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

A prepreg including a support with, for more than 90% of the weight thereof, of ceramic fibers, and a thermoreversible liquefiable gel covering, at least in part, at least one portion of the ceramic fibers. The liquefiable gel including: 20% to 60% of ceramic particles and 0% to 10% of metal particles, both as percentage by volume based on the volume of the liquefiable gel; 0.2% to 10% of a thermoreversible hydrocolloid and 0% to 7% of one or more other constituents, both as a percentage by weight on the basis of the total weight of the ceramic particles and metal particles; the balance to 100% being water. It being possible for the ceramic particles and the metal particles to be replaced, partially or completely, by precursors of ceramic particles and of metal particles, respectively, capable of forming, by heat treatment above 200° C., ceramic particles and metal particles, respectively.

A turbine engine has: a first member (22) having a surface bearing an abradable coating, the abradable coating (36) being at least 90% by weight ceramic; and a second member (24) having a surface bearing an abrasive coating. The abrasive coating (56) has a metallic matrix (64) and a ceramic oxide abrasive (66) held by the metallic matrix, the first member and second member mounted for relative rotation with the abrasive coating facing or contacting the abradable coating. At least 50% by weight of the ceramic abrasive has a melting point at least 400K higher than a melting point of at least 20% by weight of the ceramic of the abradable coating.

A turbine engine has: a first member (22) having a surface bearing an abradable coating, the abradable coating (36) being at least 90% by weight ceramic; and a second member (24) having a surface bearing an abrasive coating. The abrasive coating (56) has a metallic matrix (64) and a ceramic oxide abrasive (66) held by the metallic matrix, the first member and second member mounted for relative rotation with the abrasive coating facing or contacting the abradable coating. At least 50% by weight of the ceramic abrasive has a melting point at least 400K higher than a melting point of at least 20% by weight of the ceramic of the abradable coating.

A coated particle having excellent thermal expansion control and electrical insulation properties includes a core of a first inorganic compound containing a metal or semimetal element P; and a shell of a second inorganic compound containing a metal or semimetal element Q. The first inorganic compound satisfies 1, and the coated particles satisfy 2 and 3. 1: |dA(T)/dT| is ≥10 ppm/°C at T1 of -200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the first inorganic compound)/(a c-axis lattice constant of a crystal in the first inorganic compound). 2: in XPS of a surface of each of the coated particles, a ratio of a number of atoms of Q contained in the shell to a number of atoms of P contained in the core t is 45 to 300. 3: an average particle diameter of each coated particle is 0.1 to 100 .Math.m.

A coated particle having excellent thermal expansion control and electrical insulation properties includes a core of a first inorganic compound containing a metal or semimetal element P; and a shell of a second inorganic compound containing a metal or semimetal element Q. The first inorganic compound satisfies 1, and the coated particles satisfy 2 and 3. 1: |dA(T)/dT| is ≥10 ppm/°C at T1 of -200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the first inorganic compound)/(a c-axis lattice constant of a crystal in the first inorganic compound). 2: in XPS of a surface of each of the coated particles, a ratio of a number of atoms of Q contained in the shell to a number of atoms of P contained in the core t is 45 to 300. 3: an average particle diameter of each coated particle is 0.1 to 100 .Math.m.