514 results about "Pyrolytic carbon" patented technology

The invention belongs to the technical field of semiconductors, and particularly relates to a gradient transition composite tantalum carbide coating and a preparation method thereof.The gradient transition composite tantalum carbide coating is located on the surface of a graphite substrate material and sequentially comprises a pyrolytic carbon coating, a tantalum carbide-pyrolytic carbon composite coating and a tantalum carbide coating from inside to outside; wherein the thermal expansion coefficient of the pyrolytic carbon coating is 2.5-4.5 * 10 <-6 > / K, the thermal expansion coefficient of the composite coating is 4.5-6.0 * 10 <-6 > / K, and the thermal expansion coefficient of the tantalum carbide coating is 6.1-8.0 * 10 <-6 > / K. According to the gradient transition structure of the coating, the problem that thermal expansion coefficients between the coating and a base body are not matched is solved, the thermal shock resistance of the coating is effectively improved, meanwhile, the pinning effect can be achieved, the adhesive force between the coatings is enhanced, and the service life of a product is prolonged; compared with a single tantalum carbide coating, crack accumulation and through holes cannot be generated.

The invention discloses a method for preparing a waste gas purification catalyst from red mud and electrolytic manganese residues, a product and application thereof, and belongs to the field of solid waste resource utilization. According to the method, the preparation process is simple, efficient resource utilization of the red mud and the electrolytic manganese residues can be achieved through reasonable burdening, hydrothermal reaction and pyrolysis carbonization processes, and no other waste liquid or secondary solid waste is generated in the preparation process. The prepared waste gas purification catalyst is excellent in catalytic performance and can be used for quickly converting harmful gas of 1, 2-dichlorobenzene.

The invention belongs to the technical field of pyrolytic carbon black quality detection methods, and particularly relates to a method for determining the specific surface area of carbon black. The method for measuring the specific surface area of the carbon black comprises the following steps: firstly, adding an additive into the carbon black, stirring, centrifuging and filtering; the auxiliary agent is prepared by compounding polyacrylamide, dipolyglycerol dioleate and water; adding water for cleaning, centrifuging, filtering and drying; and finally calculating the specific surface area of the carbon black through a gas adsorption method. According to the method, the carbon black is pretreated, so that the influence of surface oxygen-containing functional groups, aromatic ring impurities and the like on nitrogen adsorption is effectively eliminated, and the problem that the pore structure of the carbon black is damaged by high-temperature degassing in a traditional method is solved through proper microwave irradiation, so that the measured specific surface area result is closer to a true value; methodologies such as precision and repeatability are more stable.

A method for preparing pyrolytic carbon black, especially for preparing pyrolytic carbon black with low ash content and high specific surface area, the method comprising: (1) providing a pyrolytic carbon black particle; (2) preparing a saturated solution of an alkali metal carbonate and immersing the carbon black of step (1) into the above-mentioned saturated solution; removing water from the saturated solution to obtain carbon black deposited with an alkali metal carbonate; (3) immersing the carbon black deposited with an alkali metal carbonate into an acid solution and performing ultrasonic treatment; (4) then filtering, washing and drying to obtain carbon black particles. A large amount of carbon dioxide generated by the reaction of the alkali metal carbonate deposited on the carbon black with the acid, in combination with ultrasonic treatment, greatly reduces the ash content and increases the specific surface area.

The invention discloses a method for recovering phosphorus through anaerobic digestion by adding sludge-based biochar, which comprises the following steps of: firing dewatered sludge serving as a raw material under an anaerobic condition to obtain carbonized carbon; or firing under an aerobic condition to obtain pyrolytic carbon, adding any sludge-based biochar obtained by firing into the hydrothermal dewatered sludge, and carrying out anaerobic digestion on the hydrothermal dewatered sludge; the hydrothermal dewatered sludge is obtained by performing hydrothermal pretreatment on dewatered sludge; and carrying out phosphorus recovery on the sludge-based biochar subjected to anaerobic digestion by utilizing a magnetic separation method. Compared with the traditional method for recovering the phosphate fertilizer from the sludge incineration ash, the recovery method disclosed by the invention is green and pollution-free, belongs to a sludge treatment mode of treating waste with waste, realizes effective combination of a heat treatment mode and a biological treatment mode, and has a good practical application value. Moreover, the prepared sludge-based biochar has the property of magnetism, so that the recovery rate of the subsequent blue iron ore is increased, and the separation difficulty and economic investment are reduced.

A composite, comprising a binder, the binder comprising one or more of polymeric, metallic, or ceramic, or pyrolytic carbon binder and a nanostructured carbon having a cellular structure. The cellular structure comprises one or more cell walls having a structure formed by a template and one or more cavities. Each cavity is substantially enclosed by the one or more cell walls and substantially unimpregnated by a liquid or solid.

The invention discloses a preparation method of an anthracite-based soft and hard carbon composite negative electrode material of a sodium ion battery, and relates to a preparation method of a soft and hard carbon composite negative electrode material. The invention aims to solve the technical problems of tedious operation and high cost of the existing preparation method of the soft and hard carbon composite sodium ion battery negative electrode material. The method comprises the following steps: crushing anthracite until the particle size is less than 75 microns, and then heating to 1000-1400 DEG C under the protection of inert gas for pyrolysis and carbonization to obtain an anthracite-based soft carbon material; and grinding and mixing with a hard carbon material to obtain the soft and hard carbon composite negative electrode material. The initial specific capacity of the soft and hard carbon composite negative electrode material is 259-260 mAh / g, the coulombic efficiency of the first circle reaches 73%-75%, the capacity retention ratio reaches 81%-84% after 500 cycles, and the soft and hard carbon composite negative electrode material has good comprehensive performance, and meanwhile, the preparation method is simple and low in cost. The invention can be used in the field of sodium-ion batteries.

The invention belongs to the technical field of lithium ion battery negative electrode materials, and particularly relates to a method for preparing porous carbon through secondary utilization of porous carbon airflow fine powder, which comprises the following steps: (S1) mixing the porous carbon airflow fine powder and a binder according to a mass ratio of 100: (15-30), and then carrying out curing reaction to obtain a precursor; the binder comprises thermosetting phenolic resin, an epoxy silane coupling agent and fumed silica; (S2) after crushing and screening the precursor, performing pyrolysis carbonization in an inert atmosphere to obtain pyrolytic carbon; and (S3) activating the pyrolytic carbon under an activation atmosphere condition to obtain the porous carbon material. According to the method, the specific adhesive is utilized, the airflow fine powder which is difficult to recycle is well reutilized, additional equipment does not need to be added, the airflow fine powder does not need to be subjected to complicated particle size screening, and secondary utilization of the airflow fine powder can be completed through existing equipment.

The invention relates to the field of ceramic matrix composite bolt preparation, in particular to a high-strength ceramic matrix composite bolt production and processing technology which comprises the following steps: obtaining a rod-shaped preform with a cladding structure and a core structure, hanging the rod-shaped preform in a vapor deposition furnace, and depositing a pyrolytic carbon interface layer on the fiber surface of the rod-shaped preform to obtain the high-strength ceramic matrix composite bolt. Carrying out high-temperature treatment; placing the treated rod-shaped prefabricated body in a vacuum dipping barrel; pumping the ceramic precursor slurry into a barrel, carrying out argon pressurization, heating, heat preservation and furnace cooling, then taking out the ceramic precursor slurry, respectively carrying out vacuum cracking treatment under low-temperature and high-temperature conditions, and after heat preservation, naturally cooling the ceramic precursor slurry to room temperature in an argon atmosphere; preparing a silicon carbide matrix to obtain segmented bars; the segmented bars are ground and machined; and a ceramic coating is prepared on the surface of the bolt with the outer threads machined, the ceramic coating is silicon carbide, and the ceramic-based composite material bolt is obtained. The method aims at optimizing the cracking temperature in the cracking treatment process of the ceramic matrix composite bolt.

The invention relates to the technical field of runner inserts in fusion reactor cladding structures, in particular to a SiC ceramic-based composite runner insert and a preparation method and application thereof.The preparation method includes the steps that a pyrolytic carbon interface is deposited on SiC prefabricated cloth, and the SiC prefabricated cloth deposited with the pyrolytic carbon interface is obtained; the preparation method comprises the following steps: mixing SiC powder, ZrO2 powder and Al2O3 powder to obtain a filler powder mixture, mixing the filler powder mixture with water, and then adding polycarbosilane to obtain mixed slurry; the mixed slurry is coated on SiC prefabricated cloth, a SiC prefabricated cloth deposition silicon carbide substrate is subjected to densification treatment and finish machining, then a silicon carbide coating is prepared through chemical vapor deposition, and the SiC ceramic-based composite flow channel plug-in is obtained. The preparation method aims at further enhancing the heat insulation performance and the insulating performance of the SiC ceramic-based composite flow channel plug-in, improving the heat insulation performance of the SiC ceramic-based composite flow channel plug-in and improving the heat insulation performance of the SiC ceramic-based composite flow channel plug-in. The average temperature at the outlet of the runner insert is increased, the pressure drop of the magnetofluid is reduced, high-efficiency energy conversion is realized, and meanwhile, long-term safe operation of a reactor is ensured.

The invention relates to the technical field of negative electrode materials, in particular to a cylindrical silicon-carbon negative electrode material and a preparation method and application thereof. The silicon-carbon negative electrode material comprises a cylindrical porous carbon skeleton with the diameter of 5-15 [mu] m and the length of 2-20 [mu] m, 10-65% of amorphous nanometer silicon is deposited on the inner wall of a pore channel, a pyrolytic carbon layer is coated on the inner wall of the pore channel, and the carbon skeleton can be doped with 0-10% of nitrogen. The preparation method comprises the steps of resin extrusion molding, carbonization, pore forming, airflow crushing, nanometer silicon deposition and pyrolytic carbon coating. The obtained material has excellent compression resistance and conductivity, is simple to prepare, and can improve the capacity, the first effect and the conductivity and reduce the expansion rate when being used for a lithium battery.

The invention provides a preparation method of a high-temperature-resistant graphite pipe for spectral analysis, and belongs to the technical field of spectral analysis, and the preparation method comprises the following steps: S1, preparing a high-purity graphite pipe matrix and carrying out surface activation treatment; s2, preparing composite sol, wherein the composite sol is formed by mixing silica sol, molybdate and phytic acid; s3, infiltrating the composite sol into the graphite matrix by adopting a vacuum-pressurization alternate impregnation process; s4, carrying out stepped heating heat treatment in an inert environment to form a SiC-MoSi composite reinforced phase; and S5, depositing a pyrolytic carbon layer on the inner wall of the graphite pipe. The silica sol, the molybdate and the phytic acid have a synergistic effect to form a SiC-MoSi composite phase, the phytic acid can prevent the molybdate from gathering and can promote the growth of SiC whiskers in heat treatment, so that the anti-oxidation temperature of the graphite pipe is increased, the temperature resistance and the heat stability of the graphite pipe are improved, and the anti-oxidation performance of the graphite pipe is improved. And finally, the use frequency of the graphite pipe is greatly increased.

The invention relates to a preparation method of a ceramic-based composite material, in particular to a preparation method of a ceramic-based composite material with a pyrolytic carbon-carbon nanotube interface, which is used for solving the problem that in the aspect of improving the thermal conductivity of an interface layer, metals such as Fe, Co, Ni and the like are widely used as catalysts for growing carbon nanotubes at present, so that the thermal conductivity of the interface layer is improved. Carbon nanotubes obtained through a traditional preparation method are prone to agglomeration and uneven in distribution, the risk of the preparation process is high, the carbon nanotubes are not suitable for large-scale production, although metal particles can be reduced through a chemical plating method, the particle sizes of the metal particles are not controlled, the distribution of the metal particles is uneven, and the requirement of a chemical vapor reduction method for distribution of an earlier-stage metal salt solution is high. And the defect is difficult to realize easily. According to the preparation method of the ceramic-based composite material with the pyrolytic carbon-carbon nanotube interface, the ceramic-based composite material with the pyrolytic carbon-carbon nanotube interface is finally obtained through pretreatment, solution A preparation, metal salt solution in-situ reduction and chemical vapor deposition in sequence.

The invention discloses a hazelnut shell-based porous adsorption carbon material as well as a preparation method and application thereof, and the method for preparing the hazelnut shell-based porous adsorption carbon material comprises the following steps: carrying out pyrolysis carbonization on hazelnut shells to obtain hazelnut shell carbon; grinding and mixing the hazelnut shell carbon and an activating agent, and activating and pore-forming; and performing acid pickling, water washing and drying on the activated and pore-formed material to obtain the hazelnut shell-based porous carbon material. The hazelnut shell is used as a raw material, and the hazelnut shell-based porous adsorption carbon material with high specific surface area, high hardness, high pore volume, excellent adsorption performance and excellent cycle stability is prepared through an alkali activation process by combining the characteristics of high hardness and rich alkali metal and alkaline earth metal of the hazelnut shell; the method can be effectively applied to treatment of textile wastewater, papermaking wastewater or dye wastewater and the like, pollutants can be removed, resource utilization of waste biomass can be achieved, and the development concept of treating pollution with waste is achieved.

The invention discloses a ceramic component gradient modified C / C-SiC-ZrC composite material and a preparation method thereof, and belongs to the technical field of carbon / carbon composite material matrix modification preparation, a carbon fiber preform and a heating element are placed in chemical liquid phase vaporization deposition equipment, a precursor solution is added until the carbon fiber preform is fully soaked, and a ceramic component gradient modified C / C-SiC-ZrC composite material is obtained; and carrying out chemical liquid phase vaporization deposition reaction to obtain the low-density C / C composite material with porosity in unidirectional gradient distribution. And putting the mixture into a graphite crucible with a carbon-rich area facing downwards and a carbon-less area facing upwards, completely putting the graphite crucible into the ceramic powder for modification, reacting and infiltrating, and cooling to room temperature to obtain the C / C-SiC-ZrC composite material with the gradient modified ceramic components. The end with high ceramic content endows the material with a high-temperature thermal protection function, the end with high pyrolytic carbon content can effectively conduct heat generated in a ceramic-rich area, and the end with low ceramic content can effectively conduct heat generated in a ceramic-rich area. Due to the gradient design from the ceramic-rich area to the carbon-rich area, the material has high-temperature oxidation resistance and ablation resistance and is light, and lightweight design of an aerospace thermal protection structure is facilitated.

The invention relates to the technical field of polymer waste treatment, and discloses a composite curing agent for curing chlorine and sulfur in polymer waste microwave thermal conversion and a preparation method and application thereof, and the method comprises the following steps: dissolving calcium nitrate and aluminum nitrate in deionized water to form an active component I solution; dissolving at least one of zinc nitrate, copper nitrate, ferric nitrate, manganese nitrate and cerium nitrate as an active component II in the active component I solution, adding citric acid into the formed mixed solution to form gel, and drying to obtain an active matter; and mixing the active matter, silicon carbide and bentonite, ball-milling, extruding and granulating, and calcining to obtain the composite curing agent. The composite curing agent disclosed by the invention can efficiently recover pyrolytic carbon, pyrolytic oil and pyrolytic gas while effectively and synergistically curing chlorine and sulfur pollution elements in situ; the curing rate of the chlorine / sulfur element can reach 80%, the recovery rate of the composite curing agent can reach 98%, and meanwhile, the raw material cost is low, and the problems of secondary pollution and equipment corrosion are avoided.

The invention discloses an expansion-resistant lithium battery pole piece material for an unmanned aerial vehicle and a preparation method of the expansion-resistant lithium battery pole piece material, and belongs to the technical field of lithium batteries. Silicon dioxide / carbon fiber composite powder serves as a matrix, the surface of the matrix is coated with a long-chain alkyl cardanol grafted glucose layer, and pyrolysis carbonization is performed to obtain the expansion-resistant lithium battery pole piece material. Carboxyl groups in glucose and isocyanate on the surface of the modified silicon dioxide / carbon fiber composite powder are subjected to an amine esterification reaction, carbon dioxide is generated, the porosity of the material is further improved, cardanol-coated lithium-containing composite powder is obtained, nanometer aluminum oxide is deposited on the cardanol-coated lithium-containing composite powder through a coprecipitation method, and the composite material is obtained. By forming a ternary composite structure with the silicon dioxide / carbon fiber composite powder as a core layer, the carbonized long-chain alkyl cardanol grafted glucose as a middle layer and the nanometer aluminum oxide as an outermost layer, the volume expansion can be better and synergistically relieved on the premise that the porosity is not affected.

The invention provides a high-strength winding thin-wall SiC composite cladding tube and a preparation method thereof. A preparation method of a high-strength winding thin-wall SiC composite cladding tube comprises the steps that silicon carbide fibers are wound and laid around a core mold, the winding pre-tightening force is smaller than or equal to 10 N. The winding mode comprises the first mode that one layer of annular winding is conducted firstly, then one layer of spiral winding is conducted, and the number of fiber intersection points in the whole annular direction at a certain position of the outer surface of the core mold is 1. One-layer annular winding is carried out firstly, then two-layer spiral winding is carried out, the number of fiber intersection points in the whole annular direction at a certain position of the outer surface of the core mold is 3, and a prefabricated body is obtained; carrying out a densification deposition process on the preform, wherein the densification deposition process comprises PyC pyrolytic carbon interface deposition, CVI chemical vapor infiltration and CVD chemical vapor deposition; and precise inner circle and outer circle machining is conducted, and the SiC composite cladding pipe is obtained. According to the preparation method disclosed by the invention, through a specific dry winding mode and a densification deposition process, the SiC composite material tube blank is higher in density and better in mechanical property.

The invention provides a method for improving the reduction performance of pyrolytic carbon in biological sludge and application of the pyrolytic carbon in reduction of steel dust and sludge, and aims at solving the problems of high energy consumption and high carbon emission of a traditional reducing agent in the steel industry and promoting efficient utilization of biomass resources in the field of steel and iron metallurgy. The method comprises the following steps: extracting biological sludge carbon through a toluene solvent to remove oil, and deashing through a sulfuric acid solution, so that the adsorption capacity and catalytic performance of the biological sludge carbon are enhanced, and the reduction efficiency of the biological sludge carbon in the ferrous metallurgy process is improved. The biological sludge carbon subjected to dust removal and oil removal treatment has the specific surface area of 159 m < 2 > / g, the pore volume of 0.14 cm < 3 > / g and the average pore size of 3.4 nm, the specific surface area is remarkably increased, the metallization ratio after the reduction reaction is also greatly improved, and the effectiveness of the method in the aspect of improving the reduction performance of the biological sludge carbon is proved. The carbon emission of the iron and steel industry can be reduced, and powerful support is provided for sustainable development of the iron and steel industry.

The invention relates to the field of energy, in particular to a graded porous carbon material and a preparation method thereof.The method comprises the steps that thermoplastic phenolic resin is prepared, and the thermoplastic phenolic resin is low-molecular-weight resole; curing the thermoplastic phenolic resin to obtain thermosetting phenolic resin; carbonizing the thermosetting phenolic resin to obtain a carbide; and activating the carbide to obtain the graded porous carbon. According to the method, the micro-mesoporous graded carbon is formed, conveying holes matched with the deposition pore volume are provided, the pore channel resistance is reduced, and the silicon loading efficiency is improved; the graphitization degree is obviously improved, so that the conductivity of pyrolytic carbon is improved.

The invention discloses a preform for a carbon-carbon composite material or a carbon-ceramic composite material, the preform is formed on the basis of a three-dimensional annular carbon fiber preform, and the preparation method adopts two times of CVI densification treatment, two times of graphitization treatment and two times of reaction melting infiltration so as to form a sandwich layer of a ceramic layer and a pyrolytic carbon layer. The friction plate of the carbon-ceramic composite material formed by the prefabricated body has a double-layer structure composed of a sandwich layer-shaped silicon carbide ceramic layer and a carbon layer, and the strength of the friction plate is higher than that of a carbon-ceramic brake disc prepared in the prior art. According to the preparation and weaving mode, the friction coefficient during braking is greatly improved, and the damage of formed silicon carbide to carbon fibers is finally avoided through two-time graphitization treatment.

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 discloses a method for preparing CNTs and hydrogen-rich gas through sludge pyrolysis, sludge is subjected to pyrolysis after being conditioned by ferric salt, pyrolysis gas is collected and reduced under the action of a Ni-Fe / NF catalyst, the Ni-Fe / NF catalyst is prepared and obtained, and the Ni-Fe / NF catalyst is obtained by dipping foamed nickel in a mixed solution containing nickel nitrate and ferric nitrate and reducing the foamed nickel. Under the action of the Ni-Fe / NF catalyst, on the basis of not changing pyrolysis conditions and not influencing preparation of pyrolytic carbon and pyrolytic oil by sludge pyrolysis, the pyrolysis gas is synchronously converted into the Ni-Fe / NF catalyst with higher value, so that the economic values of the sludge and the pyrolysis gas are improved, the influence on the environment is reduced, and the engineering application of the sludge pyrolysis technology is favorably realized.

The invention discloses a lignocellulose biomass-based hard carbon negative electrode material as well as a preparation method and application thereof. The method comprises the following steps: carrying out hydrothermal pretreatment on lignocellulose biomass by using low-corrosivity maleic acid, and regulating and controlling the composition of the lignocellulose biomass, the maleic acid and the lignocellulose to obtain a precursor rich in lignin and cellulose; in the pyrolysis and carbonization process, the thermal stability of the precursor is improved, and the lignin can more effectively inhibit the rapid concentrated pyrolysis of cellulose, so that the rearrangement of pyrolysis products is weakened. The method is beneficial for preventing overgrowth of hard carbon graphite microcrystals during high-temperature carbonization, so that the hard carbon material with large interlayer spacing and abundant small-size closed pores is prepared. The hard carbon material shows high specific capacity and excellent rate capability when being applied to the negative electrode of the sodium-ion battery. Meanwhile, xylose and furfural generated by decomposition of hemicellulose in a liquid phase can be effectively collected, and full-component utilization of biomass is achieved. The requirements of green production are met, and industrial application is easy to realize.

The invention relates to the technical field of coal gangue pyrolysis separation, and discloses a coal gangue pyrolysis carbon ash separation reactor which comprises a base and further comprises a processing mechanism which comprises a driving disc fixedly connected to the top end of the base, a driving assembly arranged above the base and a feeding cylinder arranged on the driving assembly, the conveying assembly and the separating mechanism are arranged above the base, the separating mechanism comprises a fixing plate fixedly connected to the top end of the base and a separating assembly arranged on the outer side of the fixing plate, and the processing barrel is driven by a driving disc to obliquely rotate, so that coal gangue repeatedly slides up and down in the barrel and collides with multiple layers of filter plates; according to the device, hot air flow is promoted to be in full contact with materials while particles are crushed, the problem of uneven local temperature of traditional static pyrolysis is avoided, meanwhile, a linear array structure is formed by the filter plates and the connecting rods, the material disturbance frequency is increased, 360-degree rotary heating is achieved in cooperation with hot air flow introduced through an air valve, the pyrolysis efficiency and uniformity are remarkably improved, and carbon residues are reduced.

The invention discloses a method for preparing a C / C-SiC composite material through multi-stage recovery of carbon / carbon composite material processing waste, and belongs to the technical field of C / C composite material preparation. The method comprises the following steps: carrying out multi-stage screening treatment on the carbon / carbon composite material processing waste, and screening and separating short carbon fibers and pyrolytic carbon powder; mixing the screened short carbon fibers and pyrolytic carbon powder with phenolic resin, industrial silicon powder and SiC powder, and preparing a fiber reinforced resin block in a mold pressing manner; and carrying out one-step continuous carbonization and ceramic heat treatment on the fiber reinforced resin block to finally obtain the C / C-SiC composite material. According to the method, high-added-value recycling of the C / C processing waste is achieved, the process is simple, the cost is low, operation is convenient and fast, the problems of resource waste and environmental pollution caused by existing waste treatment are solved, and the prepared C / C-SiC composite material is excellent in performance and can be widely applied to the fields of aerospace, high-end manufacturing and the like.

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 provides a fiber-bismuth ferrite-polymer converted ceramic wave-absorbing composite material and a preparation method and application thereof, and the fiber-bismuth ferrite-polymer converted ceramic wave-absorbing composite material comprises the following components by volume fraction: 10-40% of a fiber reinforcement, 1-10% of a fiber interface and 50-89% of a ceramic matrix, the ceramic matrix comprises a bismuth ferrite-based ceramic phase which accounts for 10-45% of the ceramic matrix and a polymer conversion ceramic phase which is distributed around the bismuth ferrite-based ceramic phase and accounts for 55-90% of the ceramic matrix, and the polymer conversion ceramic phase is selected from one or more of SiC, Si3N4, SiOC, SiCN and SiBCN; the fiber interface is selected from one or more of pyrolytic carbon, boron nitride and silicon carbide. The bismuth ferrite-based material is combined with the fiber-reinforced polymer conversion ceramic, so that the wave-absorbing effect can be further improved, and the high-temperature stability and oxidation resistance of the material can be remarkably improved.

The application discloses a preparation method of a carbon molecular sieve adsorbent for methane-nitrogen separation. The method comprises the following steps: 1) grinding graphite powder and placing the same in a metal salt solution, drying after sufficient stirring to obtain modified graphite; 2) placing phenolic resin powder in a metal salt solution, drying after sufficient stirring to obtain modified resin; 3) mixing the modified graphite and the modified resin, adding tar into the mixture, kneading and then extruding into a strip shape; 4) sufficiently drying the formed material, then transferring the material into a gas atmosphere calcination furnace, and calcining the material under an inert gas atmosphere for a certain time; and 5) performing programmed temperature heating on the obtained material under an inert gas atmosphere, introducing a carbon source, and depositing pyrolytic carbon on the surface of the material by a gas phase deposition method to obtain a carbon molecular sieve adsorption material. The carbon molecular sieve material is used as an adsorbent by adopting a pressure swing adsorption technology, has high adsorption capacity for nitrogen and high methane-nitrogen selectivity in methane-nitrogen separation application, and has a good industrial application prospect.