295 results about "Porous silicon carbide" patented technology

A method for manufacturing a porous silicon carbide sintered body that includes manufacturing a silicon carbide molded body by using a raw material composition containing at least silicon carbide powder, silicon powder, and a binder. The method further includes carrying out a degreasing treatment on the silicon carbide molded body to manufacture a silicon carbide degreased body, and carrying out a firing treatment on the silicon carbide degreased body to manufacture a porous silicon carbide sintered body. The raw material composition has about 1 to about 3% by weight of the total amount of the silicon carbide powder and the silicon powder in a content of the silicon powder. And, the firing treatment is carried out at a temperature allowing silicon carbide powder to mutually form intergranular necks through counter diffusion.

A jig for firing a silicon carbide based material of the present invention is a jig for firing a silicon carbide based material, which is used for placing a silicon carbide based molded body thereon upon firing of the silicon carbide based molded body, wherein a SiO source layer is formed on at least a part of the surface of the jig for firing a silicon carbide based material.

The invention discloses a preparation method of a porous silicon carbide nanofiber. The preparation method comprises the following steps of: (1) preparing a carbon nanofiber precursor polymer spinning solution; (2) performing electrostatic spinning to prepare a polymer nanofiber; (3) carrying out pre-oxidization crosslinking on the polymer nanofiber; (4) carrying out high-temperature firing on the pre-oxidized polymer nanofiber to prepare a carbon nanofiber; and (5) carrying out carbon thermal reduction on the carbon nanofiber and silicon powder to obtain the porous silicon carbide nanofiber. According to the preparation method, the morphology, the diameter and the ordering of the obtained silicon carbide nanofiber can be effectively regulated and controlled through simple means; the production cycle is relatively short so that expanded production can be conveniently realized and the preparation process is simple so that the industrial production can be conveniently realized; the porous silicon carbide nanofiber has wide application prospect in the fields of high-temperature filtration, high-temperature catalysis, catalyst carriers, heat insulation and sound insulation, gas separation, chemical sensors and the like.

Disclosed herein are a Raman spectroscopy structure comprising a porous material substrate, and a method of performing Raman spectroscopy of a sample disposed adjacent to the structure comprising the porous material substrate. Generally, the substrate includes one or more layers of a porous material such as porous silicon, porous polysilicon, porous ceramics, porous silica, porous alumina, porous silicon-germanium, porous germanium, porous gallium arsenide, porous gallium phosphide, porous zinc oxide, and porous silicon carbide. It has been discovered that such a substrate material, when excited with near-infrared light, does not exhibit undesired background fluorescence characteristic of other known Raman spectroscopy substrates.

The invention relates to a silicon carbide ceramic membrane and a preparation method thereof, belonging to the field of preparation of porous ceramic materials. The preparation method comprises the following steps: mixing SiC aggregate, a sintering aid, a toughening aid and a high-molecular binder in proportion; and then successively carrying out stirring and ball milling, molding, high temperature sintering, coating and sintering so as to obtain the porous silicon carbide ceramic membrane. The silicon carbide ceramic membrane prepared in the invention has the advantages of high porosity, great toughness, low sintering temperature, thermal shock resistance, etc., and can be widely applied to the field of high temperature gas-solid separation.

The invention relates to the technical field of porous ceramic materials and film separation, in particular to a low-temperature sintering acid and alkali resistant porous silicon carbide ceramic filmand a preparation method thereof. The method sequentially comprises the following steps of (1) support body manufacturing; (2) transition layer processing; (3) filtering layer processing; (4) film sintering process. The method provided by the invention has the characteristics that the sintering temperature is low; the production energy consumption is low; the process method is simple; the equipment requirements are low; the production cost and the investment cost are low; the control is flexible; the shaping is easy; the method is suitable for industrial customization and meets the scaled production. The porous silicon carbide ceramic film produced by the method has the characteristics of good hydrophilcity, great filtering flux, high porosity, high filtering precision, high mechanical intensity, good acid and alkali resistant performance and long service life.

The invention, belonging to the technical field of catalyst and its application, particularly relates to an ultrafine molecular sieve structured catalytic material based on a porous silicon carbide carrier and a preparation method thereof. The material comprises ultrafine molecular sieve crystals as active elements and has a hierarchically porous structure, and the whole ultrafine molecular sieve coating has catalytic activity. The method is characterized by coating a colloidal molecular sieve precursor on the surface of a modified foam silicon carbide carrier, converting the molecular sieve precursor into ultrafine molecular sieve crystals by vapor phase treatment to realize the firm combination between the coating and the carrier. According to the invention, by controlling the synthesis conditions of the colloidal molecular sieve precursor and the method of adding a pore forming agent, the size of the molecular sieve crystals, silica-alumina ratio and intercrystalline porosity can be controlled; a pore structure and the type of the molecular sieve can be designed according to the geometrical structure of a target product; and the capacity of accommodating carbon is raised, the mass transfer capability of the catalyst is reinforced, and the life of catalyst is prolonged while keeping the high activity of the ultrafine molecular sieve and high target product selectivity.

The invention belongs to the field of inorganic non-metallic materials and relates to a method for preparing porous silicon carbide ceramic. The method comprises that alkaline silica sol and silicon carbide ceramic powder are subjected to ball milling mixing to form silicon carbide ceramic water-based suspension slurry, a surfactant is added into the silicon carbide ceramic water-based suspension slurry, the mixture is stirred and foams at designed multiplying power, the foaming slurry is added with a coagulation accelerator, the mixture is stirred to form uniform slurry, the uniform slurry is poured into a mold without hydroscopicity, the alkaline silica sol is gelation-cured under the action of the coagulation accelerator, the blank is subjected to mold release and drying, then the blank is immersed with a certain amount of a C source-containing solution, and after solvent volatilization, the blank is subjected to reactive sintering at a high temperature in an argon protective atmosphere to produce the porous silicon carbide ceramic. The method has simple processes, low equipment requirements, uniform aperture distribution, controllable porosity and less pollution and can be used for industrial production of the porous silicon carbide ceramic with high porosity.

The invention discloses porous SiC fibers and a preparation method thereof. The porous SiC fibers are characterized in that the content of Si accounts for 50-60wt%, the content of C accounts for 30-40wt%, and the balance is O, the fibers are felty, the diameter of the fibers is 0.5-2.0 mu m, the porosity is greater than 60vol%, wherein the mesopore volume is greater than 50vol%, and the specific surface area is 400-800 m<2>/g. The preparation method is characterized in that poly carbon silicon alky suspension solution which can spin electrically is prepared by utilizing a precipitation fractionation principle, electrostatic spinning of the extremely dilute carbon silicon alky solution is realized, a large number of mesopore structures are introduced, thus firstly preparing poly carbon silicon alky porous fibers, and then after non-melting and sintering, the porous SiC fibers are prepared. The porous SiC fibers have good application prospects in fields such as high-temperature catalysis, heat insulation, heat preservation, sound insulation and the like. The method has universality and can be used for realizing electrostatic spinning of extremely dilute solution of other precursor polymers and for preparing corresponding porous ceramic fibers.

The invention discloses a method for preparing porous silicon carbide ceramic with high porosity which comprises preparing mix-coated powder from silicon powder, phenol resin and ethanol by a predetermined proportion, then carrying out low-temperature low-pressure modeling to produce ceramic blanks, high temperature carbonizing the ceramic blanks, finally sintering at high temperature to obtain the end product whose factor of porosity is greater than 80%.

The invention discloses a rice-husk-based porous silicon carbide ceramic material and a preparing method thereof. The rice-husk-based porous silicon carbide ceramic material is mainly prepared from rice husks and a mixture, and mass of the mixture is 30%-70% of that of the rice husks; the mixture is prepared from, by mass, 1%-30% silicon powder, 5%-40% carbon source, 1%-15% catalyst and 30%-70% binding agent. Agricultural residue rice husk serves as the main raw material of the rice-husk-based porous silicon carbide ceramic material, and is mixed with silicon powder, carbon source, catalyst and binder to prepare a semi-finished product after formation, drying and calcination; the source of the raw material which are used has wide source and low cost, the prepared product has the advantages of high porosity, big mechanical strength, good filtering effect, excellent thermal shock resistance, micro and fine hole diameter of pore, adjustable micro-morphology and the like, has wide development space and application prospect, and is suitable for industrial popularization and application.

The invention discloses a method using selective laser sintering process to produce a silicon carbide ceramic part. The method includes: weighing carbon powder, silicon carbide powder, binder and curing agent according to preset mass ratio, pouring into a ball milling tank, and performing ball milling to obtain binder-silicon carbide mixed powder; using a computer to perform three-dimensional digital modeling on the to-be-produced part, inputting three-dimensional digital model information into a selective laser sintering forming machine, using the binder-silicon carbide mixed powder as the raw material, and using selective laser sintering fast forming process to perform powder sintering forming to obtain the silicon carbide biscuit of the part; heating and curing the silicon carbide biscuit; placing the cured silicon carbide biscuit into a medium-temperature tubular sintering furnace under Ar protection so as to perform carbonization treatment to obtain a porous silicon carbide blank; performing infiltration sintering treatment on the porous silicon carbide blank under a vacuum condition to obtain the compact silicon carbide ceramic part.

A copper line-clad aluminum silicon carbide ceramic substrate applicable to radiation of a high-power LED is characterized by consisting of an aluminum silicon carbide layer (1), a copper and aluminum oxide layer (2) and copper lines (3), wherein the copper and aluminum oxide layer (2) is arranged on the alumina layer (1); the copper lines (3) are arranged on the copper and aluminum oxide layer (2); the distance between the copper lines (2) is 0.1-1mm; the widths of the copper lines (2) are 200-1000 microns; the heights of the copper lines (2) are 0.01-2mm; the copper line-clad aluminum silicon carbide ceramic substrate is manufactured by the following steps: weighing SiO2, coke and a fluxing agent, and preparing the raw materials into porous silicon carbide; heating an aluminum block and melting the aluminum block into liquid aluminum, mixing the liquid aluminum with the porous silicon carbide in a certain ratio, and preparing the mixture into aluminum silicon carbide powder and a high-thermal conductivity aluminum silicon carbide substrate; cladding copper on the aluminum silicon carbide substrate, heating at a high temperature to form an eutectic melt, and forming an aluminum silicon carbide ceramic substrate layer, the copper and aluminum oxide layer and a copper layer from the bottom up; and etching conductive copper lines. The ceramic substrate has a good application prospect in the aspect of the radiation of the high-power LED.

The present invention relates to an eco-friendly method for preparing a porous silicon carbide structure, which is capable of preparing a porous silicon carbide structure having meso- or macro-sized pores without using a harmful phenolic resin as a carbon source.

The invention relates to a method for removing carbon monoxide or volatile organic contaminants, which is realized by contacting polluted air with filler contained in a reactor. The filler of the reactor is porous graphitizing carbon or porous silicon carbide or porous graphitizing carbon or porous silicon carbide which is loaded with reactive metal components; the filler is used as adsorbent or oxidation catalyst and is heated up by accessing to electric current to realize regeneration of the adsorbent or activation of the catalyst. The method of the invention is applicable to removal of the carbon monoxide and the volatile organic contaminant discharged by households, cars or industrial polluting sources and has the advantages of safety and energy saving.

The invention provides a preparation method of a flexible porous silicon carbide micro-nano fibrofelt, relating to silicon carbide fibers. The invention provides a preparation method of a flexible porous silicon carbide micro-nano fibrofelt which is small in fiber diameter and enriched in nano-pores and can realize a flexible porous characteristic. The preparation method comprises the following steps of: mixing and uniformly stirring a good solvent and a non-solvent in proportion to obtain a mixed solvent; dissolving a silicon carbide ceramic precursor containing a silicon polymer in the mixed solvent, adding an electrolyte, and stirring until the components are fully dissolved to obtain an electrostatic spinning solution; performing electrostatic spinning on the obtained electrostatic spinning solution through an electrostatic spinning device, and continuously spinning to obtain precursor micro-nano fibrofelts with different thicknesses; and heating the obtained precursor micro-nano fibrofelts, performing drying and oxidation crosslinking, then heating again under the protection of an inert atmosphere, and performing high temperature pyrolysis to obtain the flexible porous silicon carbide micro-nano fibrofelt. The process is simple and high in production efficiency; and the fiber diameter of the obtained fibrofelt is 0.5-3 microns, and the nano-pore diameter is 5-100 nanometers.

The invention relates to porous silicon carbide ceramic and a preparation method thereof. The preparation method comprises the following steps: mixing silicon carbide, aluminum hydroxide, fumed silica, water, a dispersant and a binder so as to obtain slurry, wherein the sum of the mass of aluminum hydroxide and fumed silica accounts for 5 to 30% of the sum of the mass of silicon carbide, aluminum hydroxide and fumed silica, and a mol ratio of aluminum hydroxide to fumed silica is 2-5: 1; drying the slurry so as to obtain mixed powder; molding the mixed powder to obtain a green body; and sintering the green body in an air atmosphere at 1310 to 1340 DEG C so as to obtain the porous silicon carbide ceramic. The preparation method can prepare the porous silicon carbide ceramic with good bending resistance at a low sintering temperature.

The present invention relates to a method for preparing a porous silicon carbide ceramic based on a template. According to the present invention, the template method thinking and the characteristics of the CVI process are creatively combined, the CVI method is used to prepare the porous SiC ceramic, and the porous SiC ceramic obtained through the method has characteristics of uniform pore size, controlled porosity and large specific surface area; with the method, the technical problems of complex preparation process, high sintering temperature and the like of other template methods can be solved; and the complex member is easily prepared through the process, and the use range of the porous SiC ceramic prepared through the method is substantially expanded.

After a slurry containing powdered silicon and a resin used as a carbon source is applied by impregnation to a carbon powder-made porous structural body having a bone structure, which is formed from powdered carbon, and is then carbonized at 900 to 1,300° C. in a vacuum or an inert gas atmosphere, reaction sintering is performed at a temperature of 1,300° C. or more in a vacuum or an inert gas atmosphere. Accordingly, since a carbonized porous structural body can be obtained which has open pores generated by a volume-reduction reaction at the same time when porous silicon carbide having a good wettability to molten silicon is formed, this carbonized porous structural body is impregnated with molten silicon at a temperature of 1,300 to 1,800° C. in a vacuum or an inert gas atmosphere.

A spherical porous silicon carbide ceramic material with biologic structure is prepared from the seeds of agricultural crops (millet, rice, soybean, etc) through carbonizing in argon gas, the gas-phase osmosis of Si, liquid-phase osmosis of Si, or sol-gel carbothermal reduction for siliconizing, heat treating at 600-800 deg.C, and washing with hydrochloric acid and hydrofluoric acid.

The invention discloses a silicon carbide/copper silicon alloy codual-continuous composite and a preparation method thereof. The composite material comprises the following components in volume fraction: 35-50 percent of porous silicon carbide ceramics and 50-65 percent of copper silicon alloy, wherein the atomic percentage composition of silicon in the copper silicon alloy is 15-40 percent. The preparation method comprises two key processing steps of: preparing the porous silicon carbide ceramics and vacuum infiltrating porous silicon carbide through the copper silicon alloy. Silicon is adopted as an alloying element of copper, so that the problems of wettability and reactivity between copper and silicon carbide are solved simultaneously. In addition, the invention adopts a vacuum infiltrating process as a near net forming preparation process, and specialized die casting equipment and a specific module are not needed, so that the preparation process is simple, has low cost, and can be used for manufacturing various composites with complicated shapes.