19results about How to "Improve anti-ablation performance" patented technology

The invention provides a high-temperature-resistant carbon fiber reinforced phenolic resin composite material and a preparation method thereof. The preparation method comprises the following steps: firstly, carrying out high-temperature oxidation treatment on carbon fibers; secondly, carrying out surface modification on the carbon fibers by using a chemical modifier; then mixing the modified carbon fiber, an antioxidant and a dispersing agent to prepare slurry; performing vacuum filtration on the prepared slurry, and drying to obtain a carbon fiber blank; preparing a phenolic resin infiltration solution, and impregnating the carbon fiber blank with the phenolic resin infiltration solution; and finally, carrying out mold pressing and curing to obtain the high-temperature-resistant carbon fiber reinforced phenolic resin composite The preparation method is simple in required equipment, convenient to operate, stable in process, high in production efficiency and suitable for large-scale industrial production. According to the high-temperature-resistant carbon fiber reinforced phenolic resin composite material prepared by the preparation method, the bonding property between the carbon fiber and the phenolic resin is improved, certain toughness and strength are provided, and meanwhile, the high-temperature-resistant carbon fiber reinforced phenolic resin composite material has the advantages of ablation resistance, good oxidation resistance in a high-temperature environment and the like.

The invention discloses an ablation-resistant EPDM (Ethylene-Propylene-Diene Monomer) thermal insulation material and a preparation method thereof, and belongs to the field of thermal insulation materials, the thermal insulation material is prepared from the following components in parts by mass: 70 to 80 parts of EPDM rubber, 20 to 30 parts of liquid EPDM, 15 to 20 parts of silicon dioxide, 10 to 40 parts of high-temperature-resistant filler, 10 to 15 parts of flame retardant, 10 to 15 parts of heat-resistant fiber and 3 to 5 parts of cross-linking agent. A third monomer of the ethylene propylene diene monomer is ethylidene norbornene, and the ethylene content is 50-60%. The raw materials are placed between double rollers to be mixed, and a mixed sheet is obtained; and performing vulcanization molding on the mixed sheet to obtain the ablation-resistant ethylene-propylene-diene monomer thermal insulation material. The content of the heat-resistant fibers is increased, the aramid fibers are subjected to in-situ carbonization to form a carbonized layer structure frame, and meanwhile, the content of SiO2 is regulated and controlled, so that the content of SiO2 is matched with the increase of the fibers, and the ablation resistance of the thermal insulation material is improved.

The application discloses a kind of multi-element ultra-high temperature nanocomposite ceramic matrix composites and preparation method thereof, the multi-element ultra-high temperature nanocomposite ceramic matrix composites are composed of multi-element ultra-high temperature nanocomposite ceramic and porous fiber body, wherein multi-element ultra-high temperature nanocomposite ceramic is composed of oxygen-free silicon-based ceramic and multi-element transition metal carbonitride uniformly distributed therein, and the preparation method is: at least two metal element complexes are reacted with silicon-based polymer to obtain single-source precursor polymer;Then porous fiber body is placed in single-source precursor polymer solution for multiple times of impregnation pyrolysis, and the composite material provided by the application has a nanocomposite structure, an ultra-high temperature ceramic multi-element single-phase solid solution, the type, content and ratio of metal elements can be adjusted, the ultra-high temperature ceramic in the matrix is uniformly distributed and has a nanoscale grain size, and the method can avoid damage to the fiber during preparation, thereby achieving simultaneous improvement of the mechanical properties and oxidation ablation resistance of the composite material.

A method for preparing a high-temperature ablation-resistant chopped carbon fiber reinforced SiBCN‑MAS composite material, which relates to a method for preparing a SiBCN ceramic-based composite material. The present invention aims to solve the problem that the existing carbon fiber or cracked carbon coated carbon fiber reinforced SiBCN ceramic-based composite materials have poor contact surface bonding and limited improvement in high-temperature ablation resistance. Method: 1. Prepare cracked carbon coated chopped carbon fibers; 2. Prepare SiBCN amorphous ceramic powder; 3. Mix raw materials; 4. Sinter. The present invention is used for the preparation of high-temperature ablation-resistant chopped carbon fiber reinforced SiBCN‑MAS composite materials.

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.

This invention discloses a method for preparing high-entropy ceramic matrix composites using a reactive infiltration process, belonging to the technical field of ceramic matrix composites. The steps are as follows: at least four single-component carbides are ball-milled and mixed with a carbon source, then dispersed in a dispersion liquid to obtain a slurry; continuous fibers are woven into a preform, and an interface layer and a matrix layer are deposited to obtain a semi-dense composite material; the slurry is introduced through vacuum or pressure impregnation; and a high-entropy carbide matrix is ​​generated in situ and densified by reactive infiltration after embedding with a transition metal and its alloy. This invention solves the problems of long process cycles, high porosity, high cost, and insufficient introduction of high-entropy ceramics in existing processes, achieving rapid densification and improving the material's high-temperature stability, oxidation resistance, and ablation resistance. It is suitable for the large-scale production of thermal protection materials for hypersonic vehicles.

The invention relates to a non-expansive refractory coating and a preparation method thereof, the non-expansive refractory coating comprises a component A and a component B. The component A comprises, by mass, 15-25% of high-alumina cement, 8-12% of refractory soil, 5-10% of glass powder, 5-15% of aluminum hydroxide, 5-10% of hollow glass beads, 2-5% of silica fume, 3-5% of an ethyl cellulose composite system, and the balance modified vitrified microbeads; the component B comprises 10-20% of lithium silicate, 5-10% of an acrylic emulsion, 5-15% of a pure acrylic emulsion, 0.1-0.3% of a water reducing agent, 1-2% of a wetting agent, 1-3% of a coalescing agent and the balance of water; the modified glass beads comprise titanium dioxide composite glass beads, tetrabutyl titanate and silver. The coating has the effect of improving the fire resistance of the coating.

The invention provides a ceramic matrix composite air rudder and a preparation method thereof. The air rudder comprises a rudder leading edge, a rudder skin and a rudder framework, and the rudder skin and the rudder leading edge are connected with the rudder framework through connecting screws; wherein the rudder leading edge is formed by molding a hafnium modified C / SiC ceramic matrix composite material, and the rudder skin, the rudder skeleton and the connecting screw are all formed by molding a C / SiC ceramic matrix composite material. According to the scheme, all the components are formed by adopting different ceramic matrix composite materials, the rudder leading edge is made of the hafnium modified C / SiC ceramic matrix composite materials, and the composite materials have excellent high temperature resistance and ablation resistance; the rudder framework and the rudder skin are made of C / SiC ceramic-based composite materials, the composite materials enable the rudder framework and the rudder skin to have excellent bearing capacity, meanwhile, the connecting screws are made of the C / SiC ceramic-based composite materials, and the thermal matching performance of the ceramic-based composite materials, the rudder leading edge, the rudder framework and the rudder skin is good. Therefore, the connection between the rudder leading edge and the rudder skeleton and the rudder skin is more reliable.

The application provides a gradient wave-transparent heat shield forming method, comprising the following steps: S1, preparing a preform of a heat shield; S2, configuring ceramic slurry; S3, fusing the ceramic slurry into the preform of the heat shield to form a green body of the heat shield; S4, placing the green body of the heat shield into the ceramic slurry to densify the green body of the heat shield; and S5, sealing a large port of the green body of the heat shield and performing solution infiltration on the green body of the heat shield by using polytetrafluoroethylene to form the heat shield. The heat shield prepared by the method not only has the functions of bearing and transmitting waves, but also has excellent heat insulation and heat protection functions.

The application discloses a tubular object inner wall double-glow plasma processing device, which comprises an electrode rod and a bottom disc; the bottom disc is connected with a target material tray through a first ceramic support, and the bottom disc is connected with a workpiece tray through a second ceramic support; the target material tray is provided with a target material one and a target material two, and the target material one and the target material two are in a disc shape; a hole with the same inner diameter as the workpiece is reserved on the workpiece tray, and a hollow heat preservation cover is further arranged on the workpiece tray; the workpiece is arranged at the middle position of the target material one and the target material two, and the center lines of the target material one, the target material two, the workpiece and the hollow heat preservation cover are coincident; the target material tray is connected with an electrode rod one, and the workpiece tray is connected with an electrode rod two. The application further discloses a processing method of the tubular object inner wall double-glow plasma processing device. The outer walls of the two metal target materials and the inner wall of the tubular object are at equal intervals and are located on the upper and lower sides of the tubular object, the film layer is uniform and dense, no hole and crack appear, the film layer is combined with the base body in a metallurgical way, and the service life is improved.

The application provides a quartz fiber composite surface high-temperature-resistant waterproof coating and a preparation method thereof. The coating is ytterbium silicate (YbSiO5) ceramic, is prepared by using a low-pressure plasma spraying process, has a thickness of 0.05-0.30 mm, a porosity of not more than 5%, and a thermal expansion coefficient of less than 4*10 ‑6 / K. A laser etching process is selected for a quartz fiber composite pre-spraying treatment process, X-direction and Y-direction fibers are subjected to roughening and densification treatment, and Z-direction fibers are not treated, so as to form a grid. On the one hand, the grid maintains the integrity of the fiber bundle, and on the other hand, the surface roughness is controllable, so that the coating bonding force can be greatly improved. The coating bonding strength is greater than or equal to 1 MPa, the coating has no cracking or peeling in a prepared state, and the surface has super-hydrophobic effect. The ytterbium silicate coating has good durability, can be stored stably for a long time, does not discolor or age and fall off, is resistant to 1600 DEG C ablation, and has a water immersion weight gain rate of not more than 0.02 g / (cm 2 *h) after ablation.

The application provides a manufacturing method of a three-dimensional braided preform with low fiber volume content, which comprises the following steps: selecting fibers, braiding the fibers to form a first three-dimensional braided bundle, and the fiber volume content in the first three-dimensional braided bundle is 40%-60%; braiding the first three-dimensional braided bundle again to form a second three-dimensional braided preform, and the fiber volume content in the second three-dimensional braided preform is 20-35%. The three-dimensional braided bundle with the same thickness is used to replace the fiber bundle composed of single filaments, so that the size and distribution of the gap in the preform are more uniform, which is beneficial to the densification of the subsequent curing process, reduces the porosity, and improves certain structure and physical and chemical performance indexes.

The application relates to the technical field of ablation-resistant materials, in particular to a high-performance composite material and a preparation method thereof, which comprises the following steps: surface modification of coated carbon fibers and carbon nanotubes by using silane coupling agents respectively to obtain modified carbon fibers and modified carbon nanotubes; uniform stirring of polyphenyl ether resin, an antioxidant, anti-precipitation flame-retardant microspheres and the modified carbon nanotubes to obtain a mixture; side feeding of the modified carbon fibers in a double-screw extruder, extrusion granulation and preparation of the high-performance composite material. By adding the coated carbon fibers, the anti-precipitation flame-retardant microspheres and the carbon nanotubes in the resin matrix, the ablation resistance and the friction resistance of the prepared composite material are greatly improved; specifically, the zirconium oxide film is coated on the surface of the carbon fibers, the coated carbon fibers have the characteristics of high-temperature oxidation resistance, corrosion resistance and high hardness, and the coated carbon fibers and the carbon nanotubes jointly act, so that the overall performance of the composite material is enhanced.

The invention relates to a high-toughness ultrahigh-temperature ceramic-based composite material and a preparation method thereof. The method comprises the following steps: preparing a high-thermal-conductivity fiber preform; preparing an interface layer on the fiber surface of the high-thermal-conductivity fiber preform through a chemical vapor deposition method to obtain a porous carbon / carbon matrix; uniformly dispersing the boron nitride nanotubes in the hafnium-zirconium composite ceramic precursor solution through sanding and high-pressure homogeneous dispersion technologies to obtain a boron nitride nanotube reinforced hafnium-zirconium composite ceramic precursor solution; a boron nitride nanotube reinforced hafnium zirconium composite ceramic precursor solution reacts with a porous carbon / carbon matrix through a precursor impregnation and pyrolysis process, and the high-toughness ultrahigh-temperature ceramic matrix composite material is prepared. The high-toughness ultra-high-temperature ceramic matrix composite material prepared by the method comprises a hafnium zirconium carbon solid solution ceramic matrix and has the advantages of excellent mechanical property and ablation resistance and the like, the room-temperature mechanical property (room-temperature toughness) is remarkably improved, and the line ablation rate in an oxyacetylene ablation environment is remarkably reduced.

The application relates to the technical field of ceramic materials, and discloses a preparation method of a high-temperature ablation-resistant (Hf-Zr-Nb)C ternary carbide entropy ceramic. First, HfO2, ZrO2, Nb2O5 and C powder are mixed and then heat-treated in a high-temperature heat treatment furnace to prepare (Hf-Zr-Nb)C entropy ceramic powder by using a carbothermic reduction reaction; then the powder is pressed to obtain a ceramic block; finally, the ceramic block is sintered by using a pressureless sintering device to obtain the (Hf-Zr-Nb)C ternary carbide entropy ceramic. Compared with the existing precursor impregnation and pyrolysis and discharge plasma sintering densification technology, the pressureless sintering technology is simple in process, can greatly reduce the production cost, and can improve the yield. The entropy carbide ceramic block has good ablation resistance. The application provides technical support for the application of the high-temperature ablation-resistant entropy carbide ceramic material to the hot end components of space-aircraft.

The invention discloses a thrust regulating device for a variable thrust solid rocket engine with drive cooling integration, comprising a throat plug assembly, a high-pressure cold air source and a cold air channel; the throat plug assembly is arranged at the convergence section of the nozzle, the throat plug assembly comprises a base and a throat plug, a throat plug driving cavity is arranged in the base, the first end of the throat plug is slidably connected in the throat plug driving cavity, the second end of the throat plug is located at the throat of the nozzle, and a tension piece is connected between the throat plug and the base; the high-pressure cold air source is arranged outside the nozzle, one end of the cold air channel is connected to the throat plug driving cavity, and the other end is connected to the high-pressure cold air source after passing through the wall of the nozzle; an air film hole is arranged on the throat plug, one end of the air film hole is connected to the throat plug driving cavity, and the other end is connected to the nozzle. The invention is applied to the field of rocket engines, and can realize the driving movement of the throat plug on the basis of avoiding adverse effects on the engine charge and performance, and effectively reduce the high-temperature ablation of the throat plug by the combustion chamber gas during the working process.

The application discloses a contact structure with active vacuum arc dispersing function based on internal phase change driving, which comprises a static side contact piece, a static side conductive rod fixedly connected with the static side contact piece, a dynamic side contact piece oppositely arranged with the static side contact piece, and a dynamic side conductive rod fixedly connected with the dynamic side contact piece, wherein arc dispersing devices are arranged in the static side contact piece and the dynamic side contact piece, and the two arc dispersing devices are symmetrically arranged with the radial center line of the contact structure as the symmetric axis. The arc dispersing device is a hollow sealing structure, the side close to the contact surface is a flexible metal diaphragm, the inside is filled with liquid low-boiling point working medium, and the bottom is provided with a capillary core structure made of porous sintered material. The contact structure can drive the phase change of the built-in working medium by the energy of the arc itself, generate transient mechanical pulse to make the arc root continuously move on the anode surface, thereby destroy the stable heat conduction of the arc to the local anode, inhibit the anode ablation from the source, and improve the anti-ablation ability and service life of the vacuum switch.

The present invention discloses a silicon carbide thick epitaxial wafer for high-voltage devices, which effectively solves the problems of crystal defects and poor ablation resistance of the epitaxial wafer. By coating a modified carbon film on a silicon carbide substrate, carbon atoms of the carbon film migrate during epitaxy and annealing to supplement carbon vacancies in the epitaxial layer, thereby achieving the purpose of repairing carbon vacancies and improving the carrier life of the silicon carbide epitaxial wafer. Secondly, aluminum particles are doped in the modified carbon film to improve its ablation resistance. Al has a high melting point and a large latent heat of phase change, high thermal conductivity, and good high-temperature oxidation resistance. The Al2O3 formed by oxidation has the advantages of high melting point, low thermal expansion coefficient, good mechanical properties and corrosion resistance, etc. It can act as a heat insulation layer and prevent oxygen from diffusing into the internal SiC layer, realizing self-healing of surface cracks, significantly improving the ablation resistance of the silicon carbide thick epitaxial wafer, and is also of great significance to the development of semiconductor devices.

The invention discloses a gradient density fiber reinforced phenolic aldehyde / vermiculite composite material and a preparation method thereof, and belongs to the technical field of composite material preparation. The invention aims to solve the problems that an existing composite material homogeneous structure is difficult to consider both surface ablation resistance and internal heat insulation, a coating is easy to peel off and thermal expansion is mismatched. The composite material is prepared through the processes of gradient density preform design, phenolic aldehyde / vermiculite nano-composite impregnation, sol-gel construction of a porous structure, ceramic precursor brush coating and high-temperature cracking to form a compact ceramic layer. The carbon-based composite material which is low in density, high in specific strength, efficient in interior heat insulation and excellent in surface ablation resistance can be obtained.