126 results about "Ultrahigh temperature ceramics" patented technology

The invention relates to a porous TaC superhigh-temperature ceramic and a preparation method thereof. The specific first pore-forming agent and the specific second pore-forming agent are adopted, the first pore-forming agent comprises the metal simple substance and the carbon powder, the second pore-forming agent comprises the metal oxide capable of reacting with TaC, and the melting point of the metal simple substance is between 1495 DEG C and the melting point of the second pore-forming agent, so that the mechanical property of the ceramic and the effect of generating pores can be improved; various properties of the ceramic at high temperature are further improved; the weight ratio of the metal simple substance to the carbon powder to the metal oxide is 1: (0.2-5): (0.2-5), and the compact TaC porous ceramic with large porosity can be prepared on the basis of excellent crystallinity. The design not only ensures excellent crystallinity, but also enables the prepared TaC porous ceramic to have uniform porosity and a compact structure, is suitable for application in an extreme environment, and particularly shows excellent performance in an ultrahigh-temperature occasion.

The invention relates to a double-rare-earth crystal inhibition reinforced modified ultra-high-temperature protective coating as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a CVD-SiC inner coating on the surface of a matrix material by adopting a chemical vapor deposition method; a slurry sintering method is adopted, and a double rare earth (DRE) doped silicon-based structure anti-oxidation middle layer is prepared on the surface of the CVD-SiC inner coating; and preparing the PVD-ZrC thermal ablation prevention outer coating on the rare earth doped silicon-based anti-oxidation layer by adopting a physical vapor deposition method. According to the SiC / dRe coated Si-ZrSi2-ZrB2 / ZrC coating provided by the invention, the crystallization growth of SiO2-TGO in a silicon-based component structure is inhibited by doping rare earth oxide (REO) and / or rare earth carbide (REC), so that the stress accumulation and thermal expansion mismatch effect of the coating in a thermal service process is greatly relieved. Meanwhile, the complementary advantages of silicon-based ceramic and ultra-high-temperature ceramic in the aspects of oxidation resistance and ablation resistance are fully combined, the thermal protection capacity of the coating under the ultra-high-temperature condition is improved, the service life of the coating is remarkably prolonged, and the service stability of the coating is remarkably improved.

The invention relates to the field of superhigh-temperature ceramic coating precursor powder, in particular to a preparation method of ZrB2-SiC-ZrSix gradient superhigh-temperature ceramic coating precursor powder. The preparation method comprises the following steps: firstly, taking Zr, B4C and Si as raw materials, mixing according to a proportion, and then briquetting; and putting the briquetting material into a combustion synthesis furnace, and starting a combustion synthesis reaction in a vacuum environment. And after the combustion synthesis reaction is finished, taking out a product, and carrying out secondary crushing to obtain ZrB2-SiC-ZrSix gradient ultra-high-temperature ceramic coating precursor powder. The problem of high-temperature cracking caused by large difference of thermal expansion coefficients of components of a traditional alloying system and a graphite matrix is avoided. The problem that a traditional SiC-based system is difficult to alloy is solved, alloying compounding of the amorphous metal silicide ZrSix is coordinated, and the high-oxygen-barrier strengthening method has the advantage that high-oxygen-barrier strengthening is achieved through multiphase alloying of powder.

The invention provides ZrB2 / SiC / TiB2 ultrahigh-temperature ceramic and a preparation method thereof, and belongs to the field of ultrahigh-temperature ceramic. The preparation method comprises the following steps: preparing SiC / TiB2 composite particles, modifying and compounding the SiC / TiB2 composite particles, preparing ceramic slurry, forming and calcining. The compounding step comprises the following steps: putting modified SiC / TiB2 composite particles and modified ZrB2 particles into N-methyl pyrrolidone, uniformly stirring, adding 4, 4 '-bismaleimide diphenylmethane, and stirring at 110-115 DEG C for 2.8-3.2 hours to obtain ZrB2 / SiC / TiB2 particles; the ceramic product prepared by the invention is high in interface bonding strength, uniform in internal structure, relatively high in toughness and strength, good in temperature resistance, stable in overall performance and excellent in comprehensive performance.

The invention belongs to the technical field of ultrahigh-temperature ceramic materials, and discloses a high-purity porous tantalum carbide ceramic and a preparation method and application thereof.The preparation method comprises the steps that a porous graphite substrate is horizontally placed in a vertical vapor deposition chamber, after the chamber is vacuumized, argon is introduced, the reaction air pressure is increased to 10-100 mbar, and the graphite substrate is heated to the deposition temperature of the tantalum element; inorganic tantalum salt and hydrogen are conveyed into the cavity, and tantalum element deposition of the first area is achieved; argon is introduced into the reaction chamber, the reaction air pressure is pressurized, the carrier gas flow of the inorganic tantalum salt is increased, the deposition temperature of the tantalum element is increased, tantalum element deposition of the second area is achieved, and the process is repeated to achieve sequential deposition of the tantalum element on the porous graphite substrate from inside to outside; after the tantalum element is completely deposited, the high-purity porous graphite substrate is heated and reacts to obtain tantalum carbide, reaction conditions are adjusted, so that reaction airflow gradually permeates at different depths of the porous material, and Ta is uniformly deposited at different positions.

The invention discloses a metal-free catalyst ZrC whisker as well as a preparation method and application thereof, and belongs to the technical field of ultrahigh-temperature ceramic materials. The preparation method comprises the following steps: dissolving a zirconium source and sodium fluoride in N-N, dimethylformamide to prepare a metal salt solution; adding a carbon source into the metal salt solution to obtain a spinning precursor solution; wherein the carbon source is simultaneously used as a carbon source and a spinning auxiliary agent, and the carbon source is polyacrylonitrile or polyvinylpyrrolidone; carrying out electrostatic spinning by adopting the spinning precursor solution to obtain a primary spun yarn; and carrying out high-temperature carbonization on the initial spinning yarns to obtain the ZrC crystal whiskers. As no metal catalyst is used, the ZrC whisker prepared by the method is free of impurities and high in purity, and large-scale and simple preparation of the ZrC whisker can be realized.

A preparation method of porous hafnium carbide superhigh-temperature ceramic is characterized by comprising the following steps: dispersing graphene oxide in a solvent to form a graphene oxide dispersion liquid, mixing a monomer hafnium source solution with the graphene oxide dispersion liquid, and carrying out hydrothermal treatment on a hafnium oxide carbon precursor network structure to obtain the porous hafnium carbide superhigh-temperature ceramic. The organic-inorganic hybrid precursor is subjected to two-stage heat treatment, the first stage is inorganic treatment, the second stage is carbon thermal reduction reaction, and the porous hafnium carbide ultrahigh-temperature ceramic material is obtained. Graphene oxide is used as a structure-directing agent and an in-situ carbon source, a monomer hafnium source is uniformly anchored on the surface of a GO sheet layer on the molecular scale, an organic-inorganic hybrid precursor is formed, after the precursor is subjected to hydrothermal crosslinking, Hf species and a carbon skeleton are highly mixed on the nanoscale, and the Hf / GO composite material is obtained. And the subsequent carbon thermal reduction reaction can be efficiently completed in a low-temperature interval of 1300-1450 DEG C.

The invention provides a preparation method of an ultrahigh-temperature ceramic-based composite material with a layered structure, and relates to the technical field of ceramic-based composite materials. The method specifically comprises the steps that a PyC interface is deposited on the surface of a porous prefabricated body, then a SiC matrix and a PyC matrix are sequentially deposited on the surface of the PyC interface, then the porous prefabricated body is placed in molten salt powder containing metal powder and chlorine salt powder to be subjected to embedding treatment, then a carbon source is introduced, alloy powder serves as a raw material, reaction melt infiltration treatment is conducted on the carbon composite material, and the SiC / PyC composite material is obtained. The superhigh-temperature ceramic matrix composite material with the layered structure is obtained. Compared with the prior art, the preparation method has the advantages that molten salt is used as assistance, the ultra-high-temperature ceramic layered matrix is prepared on the semi-compact C / SiC composite material by adopting an embedding method, and finally, the densification of the composite material is realized by using a reaction melt infiltration process, so that the problem that the mechanical property of the ultra-high-temperature ceramic matrix composite material is poor due to the fact that carbon fibers are damaged by an existing RMI process is solved.

The invention relates to a low-expansion, ablation-resistant and heat-insulating integrated composite material and a preparation method thereof, and belongs to the field of ceramic-based composite materials. Comprising the following steps: putting a fiber reinforcement into a high-temperature furnace, and carrying out glue removal treatment in a vacuum state to remove a surface glue layer; adding low-expansion ceramic powder and ultrahigh-temperature ceramic powder into the ceramic precursor, and carrying out ball milling and uniform mixing to obtain a mixed solution; introducing the mixed solution into the central area of the fiber preform by adopting an injection mode, soaking the fiber preform in the mixed solution, soaking the mixed solution into the fiber preform by adopting a vacuum impregnation and pressure impregnation mode, and fully impregnating, compounding and curing; and putting the cured green body into a high-temperature atmosphere furnace for cracking, and obtaining composite materials with different densities by controlling the number of times of impregnation and cracking. The prepared composite material has excellent heat insulation, ablation resistance and bearing performance, has more reliable thermal stability and reliability, is simple in process and short in period, and can be applied to the fields of ultra-high-speed aircrafts and the like.

The invention relates to a high-performance hafnium-based ultrahigh-temperature ceramic-based composite material and a preparation method thereof. The method comprises the following steps: depositing pyrolytic carbon on the carbon fiber surface of a carbon fiber preform through a CVD (Chemical Vapor Deposition) method; preparing a hafnium oxide interface layer on the surface of the pyrolytic carbon through an atomic layer deposition method, and performing ultra-fast annealing treatment to form a pyrolytic carbon-hafnium oxide composite interface layer; carrying out a reaction with a matrix containing a pyrolytic carbon-hafnium oxide composite interface layer through an impregnation pyrolysis method; a hafnium carbide coating is prepared on the surface of the composite material matrix through a CVD method; and preparing a hafnium oxide coating on the surface of the hafnium carbide coating through an atomic layer deposition method, and carrying out ultra-fast annealing treatment to prepare the high-performance hafnium-based ultra-high-temperature ceramic-based composite material. According to the preparation method, the pyrolytic carbon-hafnium oxide composite interface layer is prepared by adopting an atomic layer deposition process and depending on ultra-fast annealing treatment, and meanwhile, the hafnium carbide-hafnium oxide composite coating is prepared, so that the mechanical property of the composite material in a high-temperature aerobic environment is remarkably improved.

The invention relates to an ultra-high-temperature ceramic nanowire toughened ultra-high-temperature anti-ablation coating and a preparation method thereof. The anti-ablation capability of C / C can be further improved. The process method comprises the following steps: firstly, preparing a PyC inner coating on a C / C green body by utilizing an isothermal CVD (Chemical Vapor Deposition) method; a catalyst is introduced to the surface of the PyC inner coating by brushing a Ni (NO3) 2 ethanol solution, and ultrahigh-temperature ceramic HfC nanowires (hereinafter referred to as HfCnw) are grafted through catalytic chemical deposition; and the SiC / HfC composite coating is prepared by a slurry brushing method. According to the PyC / HfCnw / HfC-SiC coating provided by the invention, the ceramic coating is subjected to cross-scale toughening / reinforcement through HfCnw, and meanwhile, the complementary advantages of the HfC-SiC composite coating in the aspects of oxidation resistance and ablation resistance are fully utilized, so that the mechanical properties, oxidation resistance and thermal shock resistance of the coating are improved, and the service life of C / C in a high-temperature oxygen-containing gas flow scouring environment is prolonged.

The invention relates to a preparation method of a composite coating with high structural stability, repeated use and ultra-high temperature ablation resistance. The preparation method comprises the following steps: (1) uniformly mixing ultrahigh-temperature ceramic powder, modifier powder, a dispersing agent and a solvent to obtain a mixture; (2) adding chopped fibers into the mixture, and performing ultrasonic dispersion to obtain slurry; (3) immersing a base material in the obtained slurry so that the surface of the base material is uniformly coated with the slurry, and then drying and curing to form a coating on the surface of the base material; (4) performing high-temperature heat treatment on the base material after the coating is formed in the step (3) in an inert atmosphere; and (5) densifying the coating subjected to high-temperature heat treatment through precursor impregnation cracking or reactive infiltration to obtain the reusable ultra-high-temperature ablation-resistant composite coating with high structural stability.

The invention discloses a method for improving the surface bonding strength of an ultra-high-temperature ceramic coating through additive coarsening, and belongs to the technical field of ceramic coating preparation. Bonding layer slurry is arranged on the surface of the ultra-high-temperature ceramic coating to obtain a bonding layer, then rough layer slurry is arranged on the surface of the bonding layer to be coarsened to obtain a rough layer, and the rough layer is prepared into the ultra-high-temperature ceramic coating through additive coarsening. The maximum height difference Ry of the surface in the rough layer is controlled to range from 0.15 mm to 0.5 mm, and finally sintering treatment is conducted to obtain the rough ceramic coating. According to the method, the bonding firmness of the surface coating of the ceramic material and other materials can be remarkably improved, the possible negative influence of a subtractive roughening process on the mechanical property of the material is effectively avoided, meanwhile, the method does not depend on specific equipment and material growth characteristics, and therefore the method has a wider application prospect.

The invention relates to the field of ultra-high-temperature smelting furnace temperature control systems, and discloses an ultra-high-temperature smelting furnace temperature control system based on a modular thermal field, which comprises a smelting furnace body used for accommodating raw materials and providing an ultra-high-temperature reaction environment of 1800-2200 DEG C; the modularized thermal field unit is fixed on the inner side of the smelting furnace body and comprises a plurality of standardized and interchangeable thermal field modules, and a lining of each thermal field module is made of a gradient composite ultra-high-temperature ceramic refractory material; the intelligent temperature control system comprises high temperature sensor modules which are arranged in all thermotechnical areas and used for collecting temperature, current and furnace charge data in real time; a data acquisition and preprocessing module, a machine learning control module and an execution module; a fail-safe module; and a man-machine interaction module. Compared with the prior art, the system has the advantages that through combination of modular thermal field design, gradient composite refractory materials, machine learning intelligent control and multi-physical field simulation, accurate, stable, efficient and safe control over the high-temperature smelting process is achieved.

The invention provides a micron-scale high-melting-point oxide sheet layer enhanced ultra-high-temperature ceramic-based anti-ablation composite coating and a preparation method thereof.The preparation method comprises the steps that ultra-high-temperature carbide / boride ceramic powder, silicide powder and high-melting-point metal oxide powder are mechanically mixed, and spraying mixed powder with uniform components is obtained; the mixed powder is sprayed on the surface of a base body in a plasma spraying mode, and the ultra-high-temperature ceramic-based anti-ablation composite coating containing a micron-scale oxide lamellar structure is obtained; the lamellar high-melting-point oxide phase is introduced into the ultrahigh-temperature ceramic-based composite silicide coating, so that the problem that the silicon-containing glass phase is easy to lose and splash under high-heat-flow scouring is effectively solved. The high-melting-point oxide sheet layer serves as a physical barrier, can effectively limit flowing of a silicon-containing glass liquid phase in the ablation process and allows gaseous oxidation products to escape at the same time, so that a firmly-attached composite oxide layer is formed, and the oxidation resistance and the anti-scouring and anti-stripping capacity of the coating are greatly improved.

The invention relates to a preparation method of a high-thermal-conductivity Cf / SiC composite material, belongs to the technical field of fiber reinforced ceramic matrix composite material preparation, solves the technical problems of long preparation period and high cost, and comprises the following steps: chemical vapor infiltration: depositing a pyrolytic carbon interface on the fiber surface of a fiber preform; preparing a catalyst solution; immersing the fiber preform deposited with the pyrolytic carbon interface into a catalyst solution, and carrying out vacuum impregnation; carrying out heat treatment on the pretreated fiber preform; carrying out chemical vapor infiltration on the Cf / SiC composite material on which the SiC nanowires grow; carrying out impregnation pyrolysis on the precursor, and carrying out vacuum impregnation on an ultrahigh-temperature ceramic precursor and a phenolic resin solution; and infiltrating the reaction melt to obtain the high-thermal-conductivity Cf / SiC composite material. The method is used for preparing the high-thermal-conductivity Cf / SiC composite material.

The invention discloses a preparation method and application of ultrahigh-temperature-resistant tantalum carbide ceramic aerogel, and belongs to the field of ultrahigh-temperature ceramic aerogel preparation. The preparation method of the ultrahigh-temperature-resistant tantalum carbide ceramic aerogel comprises the following steps: mixing a complexing agent and tantalum alkoxide in a polyol solvent for reaction, then adding organic acid for catalytic polymerization, then adding phenolic resin and a gel catalyst to obtain a tantalum carbide precursor solution, and carrying out sol-gel reaction to obtain tantalum carbide precursor wet gel; performing drying treatment on the tantalum carbide precursor wet gel to obtain tantalum carbide precursor aerogel, and performing pyrolysis to obtain the tantalum carbide ceramic aerogel. The tantalum alkoxide is modified by using the complexing agent, the polyhydric alcohol and the organic acid, the precursor solution in which the raw materials can stably coexist at room temperature is obtained, an oxide ceramic gel network does not need to be synthesized in the preparation process, normal-pressure drying can be performed, and the obtained tantalum carbide ceramic aerogel has the characteristics of high purity and low residual carbon content.

Various examples are provided related to ultrathin polymer-derived ultra-high temperature ceramic (UHTC). In one example, a ceramic coating includes a polymer-derived ceramic (PDC); an UHTC; and a ceramic adhesive comprising alumina (Al2O3). For example, the PDC can include silicon carbide and the UHTC can include a titanium carbide. A thickness of the ceramic coating can be less than 1 mm. In another example, a method includes providing the ceramic coating and applying the ceramic coating to a surface of a structure. For example, the structure can be an aircraft, a ship, a missile, or a rocket.

The invention discloses a preparation method of an ultrahigh-temperature ceramic and refractory metal silicide composite coating on the surface of refractory alloy, and designs a preparation method of an ultrahigh-temperature ceramic and refractory metal silicide composite coating, which comprises the following steps: (1) preparing ZrC ceramic powder with better sphericity by adopting a spray granulation method; the preparation method comprises the following steps: (1) preparing an ultrahigh-temperature ceramic / refractory metal ((Zr, Ta) C-Ta (W)) coating with a gradient structure on a Ta-10W substrate by adopting a high-speed laser cladding process; and (3) a refractory metal phase in the (Zr, Ta) C-Ta (W) coating is converted into a corresponding silicide phase through an embedding siliconizing technology, and therefore the ultrahigh-temperature ceramic / refractory metal silicide ((Zr, Ta) C-TaSi2) composite coating is obtained. The novel composite coating disclosed by the invention has the properties of uniform tissue components, relatively high hardness, high compactness, continuous multi-layer structure, high-temperature ablation resistance and the like.

The application relates to a dual-phase mosaic middle-entropy oxide anti-ablation ceramic and a preparation method thereof, and belongs to the technical field of ceramic materials. The method comprises the following steps: firstly, high-temperature heat treatment is adopted to prepare dual-phase middle-entropy oxide ceramic powders ((Hf, Zr, Ti)O2 and (Hf, Zr)TiO4) with different proportions; and then, a composite-phase mosaic structure ceramic is prepared by means of pressureless sintering. The method not only provides a theoretical basis for optimal anti-cyclic ablation performance component design of Hf-Zr-Ti-based multicomponent ultrahigh-temperature ceramic, but also lays a material foundation for the application of the prepared ceramic powder in substrate modification and coating preparation in the future. In addition, the pressureless sintering preparation of the dual-phase mosaic middle-entropy oxide anti-ablation ceramic block can realize low-cost and large-scale production. The process can not only realize low-cost and large-scale production, but also obtain uniformly distributed dual-phase middle-entropy oxides, fully exert the mutual synergistic effect among multicomponent oxides, and simultaneously improve the resistance to cyclic thermal shock and the anti-ablation performance of the ceramic block.

The invention provides an ultrahigh-temperature ceramic composite material with tensile plasticity and a preparation method thereof, and relates to the field of ceramic composite materials. The preparation method of the ultrahigh-temperature ceramic composite material with tensile plasticity comprises the following steps: extrusion molding, curing treatment and hot pressed sintering. The extrusion molding method comprises the step of simultaneously carrying out extrusion molding on the first ceramic slurry, the second ceramic slurry and the third ceramic slurry to obtain the fiber-reinforced ultra-high-temperature ceramic green body with the sandwich structure. According to the preparation method of the ultra-high-temperature ceramic composite material with tensile plasticity, the problems that existing ultra-high-temperature ceramic is prone to brittle fracture under the tensile load and poor in fracture toughness, tensile strength and tensile plasticity can be solved, and the brittle fracture tendency of the ultra-high-temperature ceramic under the tensile load effect in the ultra-high-temperature environment is improved.

The application discloses a preparation method of zirconium boride-based porous ultrahigh-temperature ceramic, and the method comprises the following steps: obtaining at least two kinds of zirconium boride powder with different particle sizes, mixing the obtained zirconium boride powder, and drying the mixed zirconium boride powder to obtain zirconium boride-based powder; the obtained zirconium boride-based powder is loosely stacked in a sintering container; the sintering container containing the zirconium boride-based powder is sintered in a protective gas atmosphere, and then zirconium boride-based porous ultrahigh-temperature ceramic is obtained. The preparation method provided by the application can quickly prepare zirconium boride-based porous ultrahigh-temperature ceramic, and the prepared zirconium boride-based porous ultrahigh-temperature ceramic has the characteristics of high compressive strength and low thermal conductivity.

The invention relates to a hafnium-based ultrahigh-temperature ceramic-based composite material and a preparation method thereof. The method comprises the following steps: mixing and weaving carbon nanotube fibers and PAN-based carbon fibers to obtain carbon nanotube fiber / carbon fiber bidirectional cloth; preparing the carbon nanotube fiber / carbon fiber bidirectional cloth into a sharp wedge profiling preform by adopting a lamination sewing process; preparing a pyrolytic carbon interface layer on the fiber surface of the sharp wedge profiling preform through a chemical vapor deposition method; the hafnium-zirconium composite ceramic precursor solution is used for dipping and filling internal pores of the sharp wedge profiling preform with the pyrolytic carbon interface layer, and the hafnium-based ultrahigh-temperature ceramic-based composite material is prepared through curing and cracking reaction. The carbon nanotube fiber / carbon fiber bidirectional cloth is woven to obtain a novel structure sharp wedge profiling preform, and a hafnium zirconium carbon solid solution is introduced as a ceramic matrix, so that the ablation resistance, the mechanical property and the heat conductivity of the ceramic matrix composite material are remarkably improved; the problem that a ceramic-based composite material prepared by a traditional technology is insufficient in ablation resistance and thermal conductivity is solved.

The invention relates to the field of ultrahigh-temperature ceramic materials, and discloses rare earth element doped quinary high-entropy boride powder and a preparation method thereof. The preparation method of the rare earth element doped quinary high-entropy boride powder comprises the following steps: 1) taking metal oxide powder, boron carbide powder and graphite powder as raw materials, and performing wet mixing to prepare mixed powder, 2) briquetting the mixed powder to prepare a green body, putting the green body into a high-temperature carbon tube furnace into which protective gas is introduced, heating, and carrying out pressureless sintering to obtain clinker; and 3) grinding the clinker to obtain the rare earth element doped high-entropy boride powder. The rare earth element doped quinary high-entropy boride powder prepared by the method has the advantages of high purity, no impurity phase, uniform metal element distribution and high rare earth element content, the preparation process is simple, the cost is low, the reaction temperature is lower, and large-scale production is facilitated.

A kind of multi-component ultra-high temperature ceramic fiber and its preparation method, belong to continuous ultra-high temperature ceramic fiber preparation technical field.Different from the method for preparing ultra-high temperature ceramic fiber by using the blend of silicon-based ceramic precursor and ultra-high temperature metal component precursor as raw material, the preparation method of the ultra-high temperature metal component precursor can realize the uniform dispersion of multi-component, and the refractory metal component content in the precursor is high, which can effectively improve the temperature resistance grade of the fiber and the high-temperature mechanical properties, oxidation resistance and other properties.The non-fusible treatment of fiber precursor is realized by using a combination of various pre-crosslinking methods, effectively solving the problems of difficult non-fusible treatment of fiber precursor caused by low softening point and few active groups of the precursor, and difficult to obtain shaped ceramic fiber.The ultra-high temperature ceramic fiber prepared by the present application has excellent high-temperature mechanical properties and oxidation resistance, and can be used as a reinforcing material for ultra-high temperature ceramic fiber reinforced ceramic matrix composites.

The application discloses a boron nitride nanotube dielectric network enhanced ZrB2-based ultrahigh-temperature ceramic wave-absorbing material and a preparation method thereof, and belongs to the technical field of wave-absorbing materials. The ultrahigh-temperature ceramic wave-absorbing material is prepared from a ZrB2 precursor and boron nitride nanotubes; the pyrolysis product of the ZrB2 precursor is spherical ZrB2 particles, and the spherical ZrB2 particles form a matrix; the boron nitride nanotubes are distributed in a network in the matrix. Part of the boron nitride nanotubes are inserted into the ZrB2 particles, and a hetero-interface exists between the boron nitride nanotubes and the matrix. The boron nitride nanotubes introduced in the application are distributed in a network in the matrix, effectively prevent the movement and transition of electrons, reduce the conductivity of the composite material, optimize the dielectric constant and impedance matching of the PDC-ZrB2, improve the wave-absorbing performance of the PDC-ZrB2, widen the selection of wave-absorbing materials in the high-temperature field, and solve the technical problem of impedance mismatching when the polymer converted ZrB2 ceramic is applied as a wave-absorbing material.

Zirconium oxide is used as a zirconium source, organic matter powder with high char yield is used as a carbon source, and mixed powder of the zirconium oxide and the organic matter powder is used as a precursor of zirconium carbide ceramic, so that the photocuring 3D printing slurry is prepared. The curing depth of the photo-curing 3D printing zirconium carbide-based ultra-high-temperature ceramic slurry can be remarkably improved, and a zirconium carbide-based ultra-high-temperature ceramic precursor blank can be quickly printed. Furthermore, by combining with reasonable selection of the sintering temperature, the preparation of the zirconium carbide-based ultra-high-temperature ceramic component can be realized.

The invention relates to a ceramic-based composite material with an ultrahigh-temperature ceramic coating and a preparation method of the ceramic-based composite material. The method comprises the following steps: annealing the ceramic-based composite material in a vacuum atmosphere, and then bombarding the surface of the annealed ceramic-based composite material by using argon ions to obtain a pretreated ceramic-based composite material; preparing an organic solution containing the yttrium ion doped hafnium-based metal organic framework material; brushing the surface of the pretreated ceramic-based composite material with an organic solution, and annealing in a vacuum atmosphere to obtain a modified ceramic-based composite material; and evaporating silicon and carbon on the surface of the modified ceramic-based composite material by using a physical vapor deposition method, and then annealing by using a Joule heat ultrafast synthesis process to prepare the ceramic-based composite material with the ultrahigh-temperature ceramic coating. The ceramic-based composite material with ultrahigh-temperature ceramic coating protection prepared by the invention has excellent high-temperature resistance, oxidation resistance and reusability, and can be used for preparing thermal structure materials in the field of aerospace.

The invention relates to the field of carbon fiber materials, in particular to a carbon fiber composite material and a preparation method and application thereof. The invention provides a preparation method of a carbon fiber composite material. The preparation method comprises the following steps: S1) coating the surface of a carbon fiber material subjected to surface modification by adopting a phenylboronic acid solution with composite slurry of ZrB2 and ZrC; s2) sintering the material obtained in the step S1) in a protective gas atmosphere; and S3) heating and oxidizing the material obtained in the step S2) in an oxygen-containing gas atmosphere to obtain the carbon fiber composite material. According to the preparation method provided by the invention, the anti-oxidative ablation ultra-high-temperature ceramic coating can be formed on the carbon fibers, the surface of the obtained carbon fiber composite material is provided with the anti-oxidative ablation ultra-high-temperature ceramic coating, and the anti-oxidative ablation ultra-high-temperature ceramic coating not only is high in ablation resistance, but also is good in stability.

Various examples are provided related to ultrathin polymer-derived ultra-high temperature ceramic (UHTC). In one example, a ceramic coating includes a polymer-derived ceramic (PDC); an UHTC; and a ceramic adhesive comprising alumina (Al2O3). For example, the PDC can include silicon carbide and the UHTC can include a titanium carbide. A thickness of the ceramic coating can be less than 1 mm. In another example, a method includes providing the ceramic coating and applying the ceramic coating to a surface of a structure. For example, the structure can be an aircraft, a ship, a missile, or a rocket.