155 results about "Ultra-high-temperature ceramics" patented technology

The invention belongs to the technical field of carbide ceramics, and concretely relates to a high-entropy carbide ultrahigh temperature ceramic powder and a preparation method thereof. The molecularformula of the ceramic powder is XCy, wherein X is at least two of Zr, Ti, Hf, V, Nb, Ta, Cr, Mo and W, and y is equal to or more than 0.6 and less 1.0. The ceramic powder has a single phase face-centered cubic structure, and has a free carbon content of 0.035 wt% or below. The ceramic powder is prepared through the steps of ball-milling mixing of at least two metal powders and C powder, and pressureless plasma sintering. The high-entropy carbide ultrahigh temperature ceramic powder is a single-phase solid solution, has the single phase face-centered cubic structure, and also has the advantages of low free carbon content, high purity, loose structure, fragility, and facilitation of post-processing applications.

The invention discloses a C/C composite material superhigh temperature ceramic coating, and a preparation method thereof. The C/C composite material superhigh temperature ceramic coating is composed of an anti-oxidation SiC transition internal layer and a superhigh temperature ablation-resistant ceramic external layer; the superhigh temperature ablation-resistant ceramic external layer is composedof more than one ingredients selected from SiC, ZrC, HfC, TaC, TiC, ZrB2, HfB2, TaB2, and TiB2. The preparation method is suitable for industrialized production, is simple in equipment, is convenientin operation, is capable of controlling coating thickness, satisfying preparation requirements of large size C/C composite material superhigh temperature ceramic coating with complex shapes, and is asuperhigh temperature ceramic coating preparation method with excellent development potential.

The invention relates to a method for preparing a Cf/ZrC-SiC superhigh-temperature ceramic composite material through a hot-pressing sintering/precursor cracking process, and concretely relates to an in-situ preparation method for the Cf/ZrC-SiC superhigh-temperature ceramic composite material by combining a precursor cracking process and a hot-pressing sintering process. The method comprises: introducing ZrSi2 powder into carbon fiber fabric, employing the hot-pressing sintering process for in-situ generation of ZrC and SiC ceramic base bodies, and employing the precursor cracking process to perform final densification processing, so as to obtain the compact Cf/ZrC-Si superhigh-temperature ceramic composite material. The superhigh-temperature ceramic composite material prepared by employing the preparation method has excellent superhigh temperature usage performance, and the method is simple in process and short in time consumption. The obtained Cf/ZrC-SiC superhigh-temperature ceramic composite material can basically satisfy practical application of some heatproof structural members, and has wide application prospect in extreme environments such as super hypersonic speed flight, aerosphere reentry, trans-atmospheric flight, rocket propulsion system and the like.

The invention belongs to the technical field of carbide ceramics, and concretely relates to a high-entropy boron-containing carbide ultrahigh temperature ceramic powder and a preparation method thereof. The molecular formula of the ceramic powder is XCyBz, wherein X is at least two of Zr, Ti, Hf, V, Nb, Ta, Cr, Mo and W, y is equal to or more than 0.6 and less 1.0, z is more than 0 and equal to orless than 0.4, and y + z = 1. The ceramic powder has a single phase face-centered cubic structure. The preparation method comprises the following steps: carrying out ball-milling mixing on at least two metal powders and C powder, carrying out pressureless plasma sintering and crushing to obtain carbide powder, mixing the carbide powder with B2O3 powder and a carbon source, and then performing high temperature sintering and crushing to obtain the ceramic powder. The ceramic powder is a single-phase solid solution, has the face-centered cubic structure, and contains the boron element, so the ceramic powder integrates the high temperature resistance of carbides and the oxidation resistance of borides, and can be used to prepare an ablation and oxidation resistant high-entropy boron-containing carbide ultrahigh temperature ceramic block or composite material.

The invention discloses a method for preparing an UHTC (Ultra-High Temperature Ceramic) matrix composite material through modification of a UHTC powder basal body. The method comprises the steps of: introducing UHTC powder and a carbon organic precursor into C/SiC with a gas hole ratio of 30 vol% to 40 vol% by adopting a vacuum pressure impregnation way; and performing in-situ reaction on melting silicon and splitting carbon in the basal body, and compacting the material through the combination of RMI (Reactive Melt Infiltration) so as to prepare a C/SiC-UHTC composite material. For one aspect, the SiC basal body protects fibers from being eroded by the melting silicon so as to improve mechanical properties of the material as the C/SiC with the gas hole ratio of 30 vol% to 40 vol% is adopted as a prefabricated body; and for the other aspect, a certain amount of the UHTC powder is introduced into the prefabricated body to improve anti-ablation performances.

A tough ultra-high temperature ceramic (UHTC) composite comprises grains of UHTC matrix material, such as HfB₂, ZrB₂ or other metal boride, carbide, nitride, etc., surrounded by a uniform distribution of acicular high aspect ratio reinforcement ceramic rods or whiskers, such as of SiC, is formed from uniformly mixing a powder of the UHTC material and a pre-ceramic polymer selected to form the desired reinforcement species, then thermally consolidating the mixture by hot pressing. The acicular reinforcement rods may make up from 5 to 30 vol % of the resulting microstructure.

A coated carbon-carbon composite material with multiple ceramic layers to provide oxidation protection from ultra-high-temperatures, where if the carbon-carbon composite material is uninhibited with B₄C particles, then the first layer on the composite material is selected from ZrB₂ and HfB₂, onto which is coated a layer of SiC coated and if the carbon-carbon composite material is inhibited with B₄C particles, then protection can be achieved with a layer of SiC and a layer of either ZrB₂ and HfB₂ in any order.

The invention relates to a preparation method of carbon fiber reinforced ultra-high temperature ceramic matrix composite material, belonging to the field of ceramic matrix composite material. The present invention firstly impregnates the soluble precursor containing ultra-high temperature ceramic constituent elements into the composite material, and then synthesizes the ultra-high temperature ceramic phase in situ through the reaction between various substances at high temperature, so as to increase the content of the ultra-high temperature ceramic phase in the matrix of the composite material and the purpose of distribution uniformity. A fiber-reinforced ultra-high temperature ceramic matrix composite material with high content of ultra-high temperature ceramics and uniform distribution is obtained by further densifying the composite material. The method has the advantages of simple process, strong repeatability and simple operation.

The invention discloses active amorphous brazing filler metal for brazing ZrB2-SiC ceramic materials, a preparation method for the active amorphous brazing filler metal and a brazing process, particularly relates to Cu-Ti-Ni-Zr high-temperature active amorphous brazing filler metal for brazing ZrB2-SiC ultra-high-temperature ceramic materials, a preparation method for the Cu-Ti-Ni-Zr high-temperature active amorphous brazing filler metal and a brazing process, and belongs to brazing filler metal in the amorphous and metallurgy fields. The components of the brazing filler metal comprise, by atomic percentage, 36.0-42.0% of Cu, 30.0-35.0% of Ti, 16.0-23.0% of Zr and the balance Ni. The melting temperature of the active amorphous brazing filler metal is 1110-1150 K, and the brazing temperature is 1183-1273 K. The Cu-Ti-Ni-Zr high-temperature active amorphous brazing filler metal obtained through the rapid condensation technology has good wettability. The room temperature shearing strength of the ZrB2-SiC ultra-high-temperature ceramic materials brazed through the amorphous brazing filler metal in a vacuum brazing mode can be as high as 160 MPa and much higher than that of Cu-based and Ag-based brazing filler metal.

The invention relates to a preparation method of a carbon fiber-reinforced ultra high-temperature ceramic-base composite material capable of being repeatedly ablated for use. Vacuum pressure is adopted to soak and combine reaction melt, the reaction melt is permeated in the conventional carbon fiber-reinforced ultra high-temperature ceramic-base composite material, and rear-earth metal elements such as La, Y, Yb, Sc, and the like are added to achieve effects of reducing volatilization of SiO2 at a high temperature, stabilizing a ZrO2/HfO2 crystal form and generating rare-earth zirconate or rear-earth hafnate. After ablation, glass-state SiO2 is formed on the material surface and filled between ZrO2 and HfO2; and a compaction layer of the rare-earth zirconate/the rear-earth hafnate is mixed to protect the material very well, so that repeatable ablation of the ultra high-temperature ceramic-base composite material is possible.

The invention discloses a ceramic matrix composite and a preparation method and application thereof, belongs to the technical field of ultra-high temperature ceramic matrix composites, and relates to a preparation method of a high-strength, high-toughness, high-density and fine-grain organization material. Zirconium diboride powder is used as a matrix phase, and zirconium disilicide powder is used as a sintering aid, so that the optimum sintering temperature, sintering pressure and sintering time of the ceramic matrix composite are lower than the requirements of the hot pressing sintering technology in the prior art; a multi-wall carbon nanotube is used as an additive for improving the internal organization structure of the ceramic matrix composite, obviously reduces the crystal grain size of the ceramic matrix composite, and improves the breaking tenacity of the ceramic matrix composite to 6.98 MPa.m<1/2>. The preparation method uses a two-step hot pressing sintering technology with fast and low-temperature characteristics to prepare the zirconium diboride ceramic matrix composite with high density and mechanical properties, and facilitates the subsequent large-scale production preparation and fiber toughening technology.

The invention provides a Cf/HfC-TaC-C composite material and a preparation method thereof, wherein a carbon fiber preform as a skeleton is immersed in a precursor solution containing a hafnium-tantalum precursor copolymer, and curing and cracking are performed to obtain the Cf/HfC-TaC-C composite material. According to the present invention, the process is simple, and the preparation period is short; and the prepared ultra-high temperature ceramic matrix composite material has advantages of excellent high-temperature resistance, excellent oxidation resistance and excellent ablation resistance,can be used as the high temperature thermal structure material of highly-hypersonic aircrafts and rocket propulsion systems, and has wide application prospect.

The invention relates to ultrahigh temperature resistant ceramic and preparation technology thereof, in particular provides a zirconium-aluminum-silicon-carbon-silicon carbide composite material and a method for preparing the zirconium-aluminum-silicon-carbon-silicon carbide composite material by in-situ reactive hot pressing. Zr powder, Al powder, Si powder and C powder in a certain stoichiometric ratio are used as raw materials; the raw materials are mixed for 5 to 50 hours by using a physical and mechanical method and are cold-pressed into cakes under the pressure of 5 to 20MPa; and the cakes are filled into a graphite mold and are heated to 1,600 to 2,400 DEG C in a hot pressing furnace into which inert gas serving as protective gas is introduced (or in vacuum) for in-situ hot pressing reaction for 0.1 to 4 hours under the hot pressing pressure of 20 to 40MPa. In the invention, the zirconium-aluminum-silicon-carbon-silicon carbide composite material with high hardness, high strength, high toughness, high ultrahigh-temperature resistance and the like can be synthesized at a relatively low temperature in a short time; and the material obtained by the method can be used at the ultrahigh temperature of above 1,600 DEG C.

The invention provides a Cf/ZrC-SiC ultra-high temperature ceramic-based composite material and a preparation method thereof. The preparation method comprises the steps of: (1) mixing a pore-forming agent, a carbon source and a ZrC ceramic precursor so as to obtain a modified ZrC-C ceramic precursor; (2) introducing the modified ZrC-C ceramic precursor into a carbon fiber prefab, and then performing curing, cracking and carbothermic reduction to obtain a nanoporous Cf/ZrC-C prefab; and (3) infiltrating molten silicon or molten silicon-zirconium alloy into the porous Cf/ZrC-C prefab, and carrying out an infiltration reaction to obtain the Cf/ZrC-SiC ultra-high temperature ceramic-based composite material.

The invention relates to a preparation method for an ultra-high-temperature ceramic modified C/C composite material. The preparation method comprises: carrying out a reaction on an ultra-high-temperature ceramic precursor solution at a high temperature by adopting a chemical liquid phase vaporized deposition process technology to generate a ceramic and pyrolytic carbon; depositing the ceramic and pyrolytic carbon; in a carbon fiber preform; and finally carrying out thermal treatment to obtain the ultra-high-temperature ceramic modified C/C composite material. The innovation of the preparation method provided by the invention is that the ultra-high-temperature ceramic modified C/C composite material is prepared by adopting the chemical liquid phase vaporized deposition process, so that the problems that a conventional process method is long in production period, has a certain damage to fiber and the like are overcome, and the ultra-high-temperature ceramic modified C/C composite material which is uniformly distributed is prepared within a short time. In the method, the component proportion, the chemical liquid phase vaporized deposition process parameters and the thermal treatment process have a great influence on the experimental result. By adjusting the experimental parameters, the ultra-high-temperature ceramic which is uniformly distributed can be obtained in the C/C composite material, so that the anti-oxidizing and ablation-resisting performances of the C/C composite material are favorably enhanced.

The invention relates to a preparation method of a screw, in particular to a preparation method of a high temperature resistant ceramic matrix composite screw. The preparation method of the high temperature resistant ceramic matrix composite screw comprises the following steps: (1) preparing a fiber perform; (2) depositing pyrolytic carbon in the fiber perform; (3) carrying out primary processing according to the size of the screw, after leaving a processing allowance, processing the fiber perform into a continuous screw rod; (4) depositing an SiC matrix in the screw rod; (5) carrying out secondary processing according to the size of the screw, and finishing in place; (6) by taking an ultra-high temperature ceramic precursor as a raw material, introducing an ultra-high temperature ceramic matrix; (7) processing the continuous screw rod into single screws, and preparing SiC coatings on the surfaces respectively; and (8) carrying out thread processing according to the requirements of the screw to obtain a screw product. According to the preparation method, by organically combining preparation and processing of a screw material, the prepared screw resists high temperature, is intact in screw tooth size and high in accuracy and has higher mechanical performance and oxidation resistance performance.

The invention relates to a manufacturing technology for super high temperature endurable ceramic. The feature is that it uses Zr powder, Al powder and C powder as raw material, taking ball milling for 10-30 hours, pressing to cake shape under 10-20MPa, encasing into graphite mold, heating to 1600-1900 degree centigrade in hot-pressing furnace at 2-50 degree centigrade per minutes under protection of noble gas, taking home position hot pressing/ solid-liquid phase reacting for 0.5-4 hours, and the hot pressing pressure is 30-40MPa. The invention could compound high purity, high intension, and corrosion proof zirconium aluminum carbon block material at low temperature and in short tie. The material could be used in the environment temperature over 1600 degree centigrade.

The invention relates to a preparation method of a zirconium boride-based ultra-high temperature monolithic material, in particular to a preparation method of an in-plane isotropic zirconium boride-based ultra-high temperature monolithic structure ceramic with high damage tolerance, and aims to solve the problems that ZrB2-based ultra-high temperature ceramic has poor damage tolerance and seriousin-plane anisotropy exists in ZrB2-based fiber monolithic ceramic. The preparation method includes: dissolving polyether sulfone in N-methylpyrrolidone, and conducting ball milling mixing with ZrB2 powder and SiC powder to obtain a ZrB2-SiC slurry, and subjecting the ZrB2-SiC slurry to extrusion curing to obtain continuous ZrB2-SiC ceramic fiber; dispersing ZrB2 powder, SiC powder and Graphene indeionized water to obtain a ZrB2-SiC-Graphene slurry; coating the continuous ZrB2-SiC ceramic fiber with the ZrB2-SiC-Graphene slurry, performing drying, and conducting prepressing, high temperature glue discharge and hot pressing sintering. The method provided by the invention solves the in-plane anisotropy problem of uniaxially arranged ZrB2-based fiber monolithic ceramic, and improves the damage tolerance. The method provided by the invention is suitable for preparation of zirconium boride-based ultra-high temperature monolithic structure ceramic.

The invention relates to a boride-silicon carbide-boron carbide ternary ceramic matrix composite material and a production method thereof. The invention relates to a ternary ceramic matrix composite material and a production method thereof, and solves the problem of poor toughness of the existing ultrahigh temperature ceramic materials. The inventive boride-silicon carbide-boron carbide ternary ceramic matrix composite material is made from, by volume percentages, 50%-80% of borides, 10%-30% of silicon carbide and 5%-30% of boron carbide. The production method comprises the following steps: (1) wet mixing and sieving; and (2) hot-press sintering. The maximal bending strength of the boride-silicon carbide-boron carbide ternary ceramic matrix composite material reaches 890 MPa, and the maximal fracture toughness thereof reaches 7.1 MPa/m<2>.

The invention relates to a ZrB2-SiC-SiB6 superhigh-temperature ceramic material and a preparing method thereof, in particular to a method for preparing an SiB6 particle and SiC particle dual-phase reinforced ZrB2 superhigh-temperature ceramic material through a hot pressed sintering method. The material has excellent high-temperature oxidation resistance, is simple in preparing process and short in period and belongs to the technical field of high-temperature thermal-protecting materials. According to a scattering method of powder of the ZrB2-SiC-SiB6 superhigh-temperature ceramic material, three kinds of powder of ZrB2, SiC and SiB6 are evenly scattered and mixed through a high-speed ball milling method, and then mixed powder can be obtained through a drying and grinding method. According to the preparing method of the ZrB2-SiC-SiB6 superhigh-temperature ceramic material, a high-temperature hot pressed sintering method is chosen, effects of different sintering techniques on the material are systematically analyzed, and a relative-compact block material can be obtained in a reasonable sintering technique condition.

The invention relates to an ultra high temperature ceramic based aerogel material and a preparation method thereof. The preparation method comprises the following steps: a soluble transition metal precursor, organosilicon and soluble carbon and boron sources are dissolved in a solvent to obtain a mixed solution for reaction at 30 to 80 DEG C to obtain a precursor sol, or the soluble transition metal precursor, the organosilicon and the soluble carbon source are dissolved in a solvent to obtain a mixed solution for reaction at 30 to 80 DEG C to obtain a precursor sol; the obtained composite precursor is cured to obtain an aerogel preform; and the ultra high temperature ceramic based aerogel material is obtained by ceramic conversion of the obtained aerogel preform under protection of atmosphere at 1000 to 1800 DEG C.

The invention discloses a textured boride base ultra-high temperature ceramic material and its preparation method. The ceramic material is a boride-silicide base composite material and is prepared from raw materials of group IVB metal, boron, silicon and transition metal. In addition, the microstructure of the composite material contains boride crystal grains of anisotropic grain growth and directional arrangement. The ceramic material is prepared by the following steps of: firstly performing reactive hot-pressing sintering to prepare densified boride base ceramic with the anisotropy crystal grain microstructure, and carrying out microstructure modulation on the ceramic which has undergone reactive hot-pressing sintering by a hot forging method to realize directional arrangement of the crystal grains of anisotropic grain growth. Therefore, the textured boride base ultra-high temperature ceramic material with the anisotropic grain growth crystal grain microstructure is obtained. According to the invention, relative density of the obtained ceramic material is greater than 98%; Lotgering orientation factor f (001) can reach up to 0.91; and its oxidation resistance, thermal conductivity and other properties all show obvious anisotropy.

The invention discloses a method for improving the bonding strength of an anti-oxidation coating on the surface of a carbon-based or ceramic-based composite material, and belongs to the technical field of anti-oxidation of carbon-based and ceramic-based composite materials. The method comprises: preparing a SiC bottom layer on the surface of a substrate material by using a CVD process; carrying out pre-oxidation treatment on the substrate material deposited with SiC to form silicon oxide on the surface; preparing a super-high temperature ceramic anti-oxidation middle layer on the surface of the pre-oxidized sample by using a slurry brushing-sintering process; and depositing a SiC outer layer on the surface of the sample. According to the present invention, with the pre-oxidation process, the bonding strength between the brushing middle layer and the SiC bottom layer can be effectively improved so as to obtain the high-bonding strength SiC/ZrB2-SiC/SiC three-layer composite anti-oxidation coating.