948 results about "Sic fiber" patented technology

A process for producing a silicon-containing CMC article. The process entails depositing one or more coating layers on silicon carbide (SiC) fibers, drawing the coated SiC fibers through a slurry to produce slurry-coated fiber material, and then processing the slurry-coated SiC fiber material to form unidirectional prepreg tapes. The tapes are stacked and then fired to yield a porous preform. The porous preform is then further densified by infiltrating the porosity therein to yield a CMC article. Infiltration can be achieved by a series of polymer infiltration and pyrolysis (PIP) steps, by melt infiltration (MI) after filling the porosity in the preform with carbon or one or more refractory metal, by chemical vapor infiltration (CVI), or by a combination of these infiltration techniques.

A fibrous silicon carbide substrate is disclosed that provides porosity through an open network of pores resulting from an intertangled arrangement of silicon carbide fibers. The fibrous structure is formed from mixing carbon or organic fibers with silicon based additives, and forming a honeycomb substrate. The carbon or organic fibers are heated in an inert environment to form silicon carbide through a reaction of the carbon in the fibers and the silicon-based additives.

A thermal treatment process for improving thermo-mechanical properties of ceramic matrix composite materials such as silicon carbide (SiC) matrix composites is described. The treatment process removes excess silicon and / or other process-related defects from the SiC-based matrix as well as the fiber interfacial coating. This invention can be practiced with minimal strength loss for as-fabricated composites formed from high-strength continuous-length ceramic and carbon-based fibers that are functionally stable to 1600° C. and above. The invention provides a method for significantly improving composite thermal conductivity and creep resistance, and for reducing composite porosity. It has been demonstrated using state-of-the-art 2D woven SiC / SiC composites containing Sylramic-iBN SiC fibers, boron-nitride-based interfacial coatings, and hybrid matrices that are based on SIC formed by chemical vapor infiltration (CVI) and by a combination of CNI, SiC particulate infiltration, polymer infiltration and pyrolysis, and melt infiltration of silicon, silicon-based alloys, and silicides.

The invention relates to a preparation method of a silicon-carbide-fibrofelt-enhanced silica aerogel composite material, and relates to an aerogel composite material. According to the invention, a carbon-rich silicon carbide micro-nano ceramic fibrofelt with small fiber diameter, high porosity, communicating pores, fast impregnation speed, and good compatibility with a substrate is prepared with a static electro-spinning technology combined with a precursor conversion method; a silica sol is prepared with an acid-alkali two-step method; with an infiltration technology, the electro-spun silicon carbide ceramic fibrofelt or precast is soaked into the sol; and through processes such as gel process, aging, curing, solvent exchange, supercritical drying, and the like, the silicon-carbide-fibrofelt-enhanced silica aerogel composite material is obtained. The prepared composite material has the characteristics of low density, large specific surface area, super-hydrophobicity, low thermal conductivity, and the like. The strength and toughness of the material are also greatly improved. The carbon-rich silicon carbide fiber has an infrared shielding effect, such that composite material thermal insulation effect and ultra-high-temperature stability can be improved.

The invention discloses microwave absorbing ceramic of a silicon carbide compound material and a preparation method thereof. The microwave absorbing ceramic has a multifunctional layer laminated structure which comprises a matching layer, a depletion layer, a dielectric layer and a reflecting layer, wherein the matching layer, the depletion layer and the dielectric layer are respectively made of a continuous silicon carbide fiber reinforced silicon carbide-based compound material; the reflecting layer is made of a continuous carbon fiber reinforced silicon carbide-based compound material; andcontinuous silicon carbide fiber and continuous carbon fiber have different electrical resistivity. The preparation method comprises the flowing steps of: selecting a reinforced material; preparing asizing agent; preparing a rough blank; and preparing a finished product. The microwave absorbing ceramic has a wider absorbing frequency band, a higher mechanical property and a heat-resistant function.

The invention discloses a wave-absorbing ceramic made of a silicon carbide composite material and a preparation method thereof. The wave-absorbing ceramic has a multifunctional superimposed structure comprising a matching layer, a consuming layer and a reflecting layer, wherein each functional layer is made of a continuous silicon carbide fiber reinforced silicon carbide-based composite material;and continuous silicon carbide fibers serving as a reinforced material of each functional layer have different resistivity. The preparation method for the wave-absorbing ceramic comprises the following steps of: selecting continuous silicon carbide fiber plain cloth; dipping and cracking the plain cloth of the consuming layer; mixing with polycarbosilane, divinylbenzene, dimethylbenzene and the like to prepare slurry; performing mould pressing, thermal crosslinking and cracking to prepare a wave-absorbing ceramic rough blank; and preparing the wave-absorbing ceramic made of the silicon carbide composite material by adopting a precursor dipping and cracking process. The wave-absorbing ceramic has wide absorption frequency band, high mechanical property and heatproof function.

The invention provides a composite core for a power grid transmission line wire and a preparation method thereof. The composite core has high strength, high toughness, high glass-transition temperature and surface cleanness. Materials of the composite core comprise a resin material and a strengthening material. The resin material comprises a thermosetting resin, a curing agent, an accelerating agent, a releasing agent, a flexibilizer and nanometer particles. The strengthening material is one kind or a plurality of kinds of carbon fiber, glass fiber, basalt fiber, boron fiber, aramid fiber, silicon carbonate fiber and protein bound iodine (PBI) fiber. The content of composite core fiber Vf=50-80%, tensile strength of the composite core is not lower than 2100MPa, and glass transition temperature of the composite core is not lower than 180 DEG C. The toughness of the composite core is remarkably improved, and breakage and cracking probability caused by brittleness factors in production, transportation and wire hanging construction processes are reduced.

The invention discloses a preparation method of a silicon carbide fiber reinforced silicon carbide composite material. The preparation method comprises the following steps of preparing a SiC fiber knitted piece, placing the SiC fiber knitted piece into a vacuum furnace to carry out chemical vapor deposition through adopting methane or propylene as feed gas and a pressure difference method to deposit a carbon coating on the surface of the SiC fiber knitted piece, carrying out a vacuum impregnation process on the SiC fiber knitted piece deposited with the carbon coating through adopting a liquid SiC ceramic precursor as impregnation liquid, putting the impregnated SiC fiber knitted piece into a mold, carrying out thermal molding crosslinking in a dynamic nitrogen atmosphere, putting the crosslinked SiC fiber knitted piece into a cracking furnace to carry out high temperature cracking in a dynamic nitrogen atmosphere, repeating a vacuum impregnation-thermal molding crosslinking-high temperature cracking cycle so as to finish preparation until the weight increment of a sample obtained after the vacuum impregnation-thermal molding crosslinking-high temperature cracking cycle is less than 1% of the weight increment of the sample obtained after the previous cycle. The preparation method has the advantages of short period, low cost, low pollution and toxic effects, etc.

The characteristics of the invention are that the spin finish aid of the organic polymer containing one or multiple of sintering auxiliary agents is in troduced before spinning. The sintering auxiliary agent is at least one of B, Al, Y, Mg, Ti, Zr. The sintering auxiliary agent can be contained in one organic polymer or different organic polymers. The organic polymer is the polymer in silazane class and silicone carbon hydride. The method improves the spinning quality. The fiber produced can bear temperature higher than 1500 deg.C with diameter less than 10 micros, possessing good antioxidation property and mechanical property, being as the new generation of the reinforcement fiber. The method is easy to realize the continuous production.

A method and apparatus for forming a plurality of fibers from (e.g., CVD) precursors, including a reactor adapted to grow a plurality of individual fibers; and a plurality of independently controllable lasers, each laser of the plurality of lasers growing a respective fiber. A high performance fiber (HPF) structure, including a plurality of fibers arranged in the structure; a matrix disposed between the fibers; wherein a multilayer coating is provided along the surfaces of at least some of the fibers with an inner layer region having a sheet-like strength; and an outer layer region, having a particle-like strength, such that any cracks propagating toward the outer layer from the matrix propagate along the outer layer and back into the matrix, thereby preventing the cracks from approaching the fibers. A method of forming an interphase in a ceramic matrix composite material having a plurality of SiC fibers, which maximizes toughness by minimizing fiber to fiber bridging, including arranging a plurality of SiC fibers into a preform; selectively removing (e.g., etching) silicon out of the surface of the fibers resulting in a porous carbon layer on the fibers; and replacing the porous carbon layer with an interphase layer (e.g., Boron Nitride), which coats the fibers to thereby minimize fiber to fiber bridging in the preform.

The invention relates to a method for manufacturing silicon carbide fibre with high temperature resistance. Low molecular silane LPS is used as a raw material and has a reaction with an organic compound containing dense elements to synthesize AL, Y-containing polycarbosilane, namely PACS and PYCS; the PACS and PYCS are manufactured into continuous PACS and PYCS fibre by melt spinning; the PACS and PYCS fibre are subjected to infusible treatment to produce infusible fibre which can control the oxygen content; and the infusible fibre is calcinated and sintered at a high temperature under the protection of an inert atmosphere, thereby preparing SiC fibre with high crystallization and high temperature resistance. The method has the advantages of simple process, convenient operation, easy implementation by utilizing equipment for producing a common SiC fibre and low manufacturing cost; and a product produced by the method has the excellent characteristics of high strength, high temperature resistance, high oxidation resistance, etc. and is suitable for batch preparation in industry.

The disclosed preparation method for SiCf / SiC composite material comprises: selecting Polycarbosilane as predecessor and domestic continual silicon carbide fiber as reinforcement phase; preparing SiC coating on SiC fiber surface; then, preparing SiCf / SiC composite material with predecessor immersion and crack technique; finally, preparing an integral anti-oxidation coating on material surface. This invention needs only simple device and short production period.

The invention relates to a nuclear fuel cladding totally or partially made of a composite material with a ceramic matrix containing silicon carbide (SiC) fibers as a matrix reinforcement and an interphase layer provided between said matrix and said fibers, the matrix including at least one carbide selected from titanium carbide (TiC), zirconium carbide (ZrC), or ternary titanium silicon carbide (Ti3SiC2).When irradiated and at temperatures of between 800° C. and 1200° C., said cladding can mechanically maintain the nuclear fuel within the cladding while enabling optimal thermal-energy transfer towards the coolant.The invention also relates to a method for making the nuclear fuel cladding.

The invention discloses a silicon carbide fibre-reinforced silicon carbide composite microwave-absorbing ceramic. The microwave-absorbing ceramic consists of continuous silicon carbide fibre-reinforced silicon carbide composite material; wherein silicon carbide fibre cloth overlaid layer by layer is used as reinforcement; the silicon carbide fibre cloth is connected into a whole in a way of sewing with carbon fibres in Z direction; the band width, of which the reflectivity is lower than -8dB in frequency band of 8GHz to 18GHz, is 6.5 GHz to 10 GHz at normal temperature; and the density is lower than 2.1 / cm <3>. The method for preparing the microwave-absorbing ceramic comprises the following steps: weaving the continuous silicon carbide fibres into silicon carbide fibre plain cloth; sewing the plain cloth into a whole body in a Z direction by carbon fibres to prepare a preformed body; dipping, pyrolyzing and densifying the preformed body repeatedly by using precursor dipping and pyrolysis technology, thus obtaining the microwave-absorbing ceramic. The product provided by the invention has advantages of simple structure, wide absorbing frequency band, light weight, thin thickness, good mechanical property, etc.

A SiCf / SiC ceramic-based composite material with composite interfaces is characterized by comprising CVD-SiC coating, a PIP-SiC matrix, the composite interfaces and SiC fiber, wherein the CVD-SiC coating is silicon carbide coating prepared through a chemical vapor deposition method, and has the thickness of 100-500 microns; the composite interfaces are formed by alternately and periodically overlapping any two or three of a BN interface, a ZrO2 interface, an LaPO4 interface and an SiC interface, and the cycle period frequency is 3-5 times; the PIP-SiC matrix is silicon carbide formed through in-situ pyrolysis of polycarbosilane; the SiC fiber accounts for 40-60% of the composite material by volume, a pyrolytic carbon layer with the thickness of 5-20 nanometers is formed on the surface thereof. A preparation method comprises the following steps: preparing multiple layers of composite interfaces on the surface of the silicon carbide fiber by different preparation processes, then fillingthe SiC matrix by a PIP method, and finally preparing the surface SiC coating by a CVD method. The SiCf / SiC ceramic-based composite material prepared through the preparation method provided by the invention is high in toughness and strong in antioxidant capacity, and the preparation process is simple.

The invention discloses a preparation method of a silicon carbide fiber with a boron nitride structure surface layer. The preparation method comprises the following steps of: 1, preparing a continuous polycarbosilane fiber through melt spinning; 2, carrying out melting-free treatment; and 3, nitriding for decarbonizing, and then sintering at high temperature. The preparation method has the advantages of simple process, convenience in implementation and low cost. The silicon carbide fiber with the boron nitride structure surface layer, prepared by the invention, has good properties of resisting high temperature and oxidization, is improved in fiber interface, and is enhanced in property of a fiber reinforced composite.

The invention belongs to the field of composite material manufacture, and relates to a method for manufacturing SiC / SiC composite material pin with a precursor infiltration and pyrolysis method. The method is characterized in that firstly, a 1K SiC fiber bundle is taken as a raw material; a fiber prefabricate of the pin is manufactured by adopting a 2D weaving mode; the pin fiber prefabricate is placed in a graphite mould for moulding, and then an interface layer is manufactured through chemical vapor infiltration (CVI); a base body is manufactured through precursor infiltration and pyrolysis (PIP), so that the SiC / SiC composite material pin is manufactured; and the manufactured SiC / SiC composite material pin is high in strength and good in tenacity. Compared with an original two-dimensional stacking structure composite material pin, the SiC / SiC composite material pin has the advantages that no layering problem exists; and before being manufactured into the pin, the two-dimensional stacking structure composite material needs to be cut and manufactured into long-strip-shaped firstly, and then is subjected to pin moulding manufacture, so that layering and performance lowering of the composite material are easily caused, and the two-dimensional stacking structure composite material pin is high in manufacture cost and low in efficiency. According to the method, the manufacture efficiency and mechanical performance stability of the pin are improved, and the method has a wide market promotion and application prospect.

The invention relates to a preparation method of silicon carbide fibers with a silicon nitride surface layer. The preparation method comprises the following steps of: using polycarbosilane (PCS) which is prepared by using organic silicon polymers through high-temperature cracking as raw materials, conducting melt-spinning to obtain continuous PCS polymer fibers, placing the continuous PCS polymerfibers in the atmosphere of air or activated gas for non-melting treatment, placing the non-melting fibers in a high-temperature atmosphere furnace for high-temperature nitration and decarbonization under the atmosphere of ammonia with certain concentration, and further sintering for densification at high temperature to obtain the silicon carbide fibers with the silicon nitride surface layer. Thepreparation method of the silicon carbide fibers with the silicon nitride surface layer has the advantages that the process and the equipment are simple, the cost of the prepared silicon carbide fibers is low and the resistivity is adjustable.

The method provides a method for in-situ growing carbon nanotubes on fiber surfaces, namely a method for directly growing carbon nanotubes on surfaces of fibers (carbon fibers, glass fibers, silicon carbide fibers, alumina fibers, high silica fibers, mullite fibers and the like). In the method, normal hexane, hexane, benzene, toluene, dimethylbenzene, ethanol or acetone is used as a carbon source, ferrocene is used as a catalyst, a sulfur compound such as sulfur, thiophene and the like are used as an accelerator, and hydrogen, argon, nitrogen, helium or the mixture of hydrogen, inert gas and the like is used as carrier gas, a horizontal reacting furnace device is used to direct grow the carbon nanotubes on the fiber surfaces under the conditions that the temperature ranges from 600 DEG C to 1000 DEG C and the carrier gas flow velocity is 10-2000ml / min. The method has the following advantage: the carbon nanotubes are directly grown on the fiber surfaces without depositing catalyst particles on the fiber surfaces in advance, which is beneficial to the large-scale growth of the carbon nanotubes on the surfaces of the fiber fabrics.

The invention relates to a method for preparing a fiber reinforced multiphase ceramic matrix composite material. The method comprises the following steps: using a carbon fiber or silicon carbide fiberas a reinforcement, and combining a slurry method to prepare a fiber prepreg, and then preparing the fiber reinforced multiphase ceramic matrix composite material by hot press forming, carbonizationand infiltration. The powder body such as ZrB2, ZrC, HfB2, and HfC are directly added into a slurry, thereby introducing an ultra-high temperature component, and improving the ultra-high temperature resistance of the composite material. The method overcomes the defects of long preparation period and high cost of the traditional fiber reinforced ultra-high temperature ceramic matrix composite material, and can prepare the ultra-high temperature ceramic matrix composite material with excellent performances in a short cycle and low cost.

A novel polycrystalline stoichiometric fine SiC fiber substantially free of impurities is produced using a novel pre-ceramic polymer. The pre-ceramic polymer is prepared by reacting a mixture of chlorodisilane, boron trichloride, and a vinyl chlorodisilane with an excess of hexamethyldisilazane to form the pre-ceramic polymer resin, which may then be melt-spun, cured, pyrolyzed and heat-treated to obtain the finished SiC fiber. The manufacturing process for the production of the fine SiC ceramic fiber allows for flexibility with respect to cross-linking, in that low-cost thermal treatments may replace more complex methods, while obtaining fibers with improved materials properties as compared to currently available SiC fibers.

The invention discloses a silicon carbide fiber solid fabric for in-situ growing carbon nano tubes, which is formed by mainly weaving silicon carbide fibers. In the invention, in-situ grown carbon nano tubes are uniformly distributed on the surfaces of the silicon carbide fibers and mutually wound to form a reticular structure. The preparation method comprises the following steps of: pretreating the silicon carbide fiber solid fabric; loading a Ni-La-Al composite catalyst by adopting a catalyst precursor vacuum impregnation-reduction method; and finally, carrying out chemical gas-phase deposition to ensure that the carbon nano tubes are in-situ grown on the silicon carbide fiber solid fabric. The invention also discloses a carbon nano tube-silicon carbide fiber mixed enhanced composite material which is prepared by using silicon carbide as a substrate and the silicon carbide fiber solid fabric as a reinforcement body by adopting a traditional precursor impregnation-conversion method. The silicon carbide fiber solid fabric has the advantages of uniform carbon nano tube dispersion, higher and controllable carbon nano tube content, good combination with fibers, and the like.

The invention discloses a multilayer structure of an SiC / SiC (silicon carbide) composite cladding tube and a preparation method of the multilayer structure. The multilayer structure of the SiC / SiC composite cladding tube is formed by alternately overlapping an SiC whisker toughening SiC composite layer and a continuous SiC fiber toughening SiC composite layer according to design needs. A three-layer overlapping structure takes the SiC whisker toughening SiC composite layer as an inner layer, a continuous SiC fiber toughening SiC composite material as a middle layer and a SiC whisker toughening SiC composite material as an outer layer; the multilayer structure can be formed by continuous alternate overlapping according to the design needs. The SiC whisker toughening SiC composite layer in the multilayer structure mainly plays a role of seal leakage prevention, meanwhile, the SiC whisker toughening SiC composite layer has high strength and toughness, the continuous SiC fiber toughening SiC composite layer plays a role of strength supporting, the multilayer structure of the SiC / SiC composite cladding tube has high crack resistance, high heat conductivity, high specific stiffness, high specific strength, excellent thermal shock and the like.

A method of producing fiber-reinforced metallic building components having a complicated three-dimensional geometric shape includes the following steps. First, metal-coated SiC fibers are applied to a metallic sectional piece having a simple geometric shape, and are then held thereon without restraint by a metallic counterpart piece. Then, the unit consisting of the sectional piece, fibers and counterpart piece undergoes plastic deformation in vacuo between mold halves by applying pressure at an elevated temperature, without bonding of the fibers to one another or to the building component metal. By further increasing the pressure and / or temperature, the molded unit is compressed further between the mold halves and is consolidated to a monolithic part by metallic bonding (diffusion welding), whereby the part, either alone or bonded to other parts, forms the building component, after cooling and removing it from the mold halves.

The production process of continuously preparing SiC fibre includes the following steps: dissolving high-molecular polymer in solvent to prepare skin solution, dissolving or dispersing the dispersingagent, high-molecular polymer, SiC powder and sintering adjuvant into solvent to prepare core solution, extruding skin solution and core solution from microhole of skin-core composite spinning component under the pressure to make skin solution cover exterior of the core solution, using wet process or dry process to solidifying fluid-flow wire, drawing, drying and winding so as to obtain raw fibre, its core portion is ceramic powder adhered by polymer and its skin portion is made of pure high-molecular material.

The invention provides a preparation method for high-temperature-resistance high-crystallized near-stoichiometric-ratio continuous SiC fiber. The preparation method comprises the steps: 1) enabling a polycarbosilane polymer to react with heterogeneous element compound to prepare a precursor and then spinning the precursor to obtain continuous fibril; 2) presintering and sintering the continuous fibril after the continuous fibril is treated in a non-melting mode to obtain the high-temperature-resistance high-crystallized near-stoichiometric-ratio continuous SiC fiber. According to the preparation method, heterogeneous elements are introduced into fiber in a precursor synthesizing process, and then boride is introduced into the fiber in non-melting or high-temperature presintering and sintering processes; a synergistic effect between the heterogeneous elements and the boride is utilized, so that SiC fiber crystal grains can rapidly grow under presintering and sintering high-temperature environment, meanwhile the SiC fiber is prevented from generating a loose and porous structure, and densification is achieved; thus, the dense high-crystallized near-stoichiometric-ratio continuous SiC fiber is obtained.

The invention discloses a SiCf / SiC ceramic-based composite material with a composite interface. The SiCf / SiC ceramic-based composite material with the composite interface has the characteristic of comprising a CVD-SiC coating, a PIP-SiC matrix, the composite interface and SiC fiber, wherein the CVD-SiC coating is a silicon carbide coating which is prepared by using a chemical vapor deposition method and has a thickness of 100-500 [mu]m, the composite interface is formed through alternate cyclic overlapping of arbitrary two or three of a BN interface, a ZrO2 interface, a LaPO4 interface and a SiC interface, and the cyclic number is 3-5 times; and the PIP-SiC matrix is silicon carbide formed through in-situ pyrolysis of polycarbosilane, the volume of the SiC fiber accounts for 40-60% of thevolume of the composite material, and a pyrolytic carbon layer of 5-20 nm thick is formed on the surface. The preparation method comprises the steps: preparing the multi-layer composite interface on the surface of the silicon carbide fiber by using different preparation processes, then filling a SiC matrix by using a PIP method, and finally preparing a surface SiC coating by using a CVD method. The prepared SiCf / SiC ceramic-based composite material has high toughness, high oxidation resistance and a simple preparation process.

The invention discloses a method for preparing an integral turbine blade disc based on a SiC fiber ceramic matrix composite material, which is used for solving the technical problem of the poor practicability of the existing integral turbine blade disc preparation method. The technical scheme is as follows. Firstly, a plane polar coordinate weaving method is adopted to prepare a turbine blade discprefabricated body unit layer, so that continuous SiC fibers are arranged in two principal stress directions in the warp direction and the weft direction. Then Z-direction puncture, sewing and die pressing are adopted to finish the shaping of the prefabricated body. A BN interface layer is prepared on the surface of the SiC fiber of the prefabricated body by utilizing a chemical vapor infiltration method. The prefabricated body of the turbine disc is pre-densified by adopting a chemical vapor infiltration process. The turbine disc blade is processed by adopting a cubic boron nitride or diamond special cutter on a multi-axis numerical control machine tool. Finally, an anti-oxidation coating is prepared. As the prefabricated body is provided with the continuous SiC fibers in two main principal directions in the warp direction and the weft direction, the bearing performance of the integral turbine blade disc is improved, the preparation period of the integral turbine blade disc is shortened, and the practicability is good.

In various embodiments, composite materials containing a ceramic matrix and a carbon nanotube-infused fiber material are described herein. Illustrative ceramic matrices include, for example, binary, ternary and quaternary metal or non-metal borides, oxides, nitrides and carbides. The ceramic matrix can also be a cement. The fiber materials can be continuous or chopped fibers and include, for example, glass fibers, carbon fibers, metal fibers, ceramic fibers, organic fibers, silicon carbide fibers, boron carbide fibers, silicon nitride fibers and aluminum oxide fibers. The composite materials can further include a passivation layer overcoating at least the carbon nanotube-infused fiber material and, optionally, the plurality of carbon nanotubes. The fiber material can be distributed uniformly, non-uniformly or in a gradient manner in the ceramic matrix. Non-uniform distributions may be used to form impart different mechanical, electrical or thermal properties to different regions of the ceramic matrix.