92results about How to "Avoid volume shrinkage" patented technology

The invention relates to a preparation method for carbon-silicon composite aerogel with low density, high ratio surface area and high pore volume. The method takes silicone gel grains as a framework structure, takes resorcinol and formaldehyde as reactant and prepares the hydrogels by the sol-gel reaction under the catalysis of alkaline catalyst. After the hydrogels are dried, high-temperature carbonization is carried out on the hydrogels under the protection of inert gases, so as to gain the carbon-silicon composite aerogel. The carbon-silicon composite aerogel prepared by the method of the invention has the characteristics of high ratio surface area, large pore volume and low density.

The invention discloses a tailing sand mortar dry blend and a mortar preparation method thereby. The tailing sand mortar dry blend comprises the following raw materials of common portland cement, sand, cellulose ether, naphthalene formaldehyde water reducer and re-dispersible latex powder, wherein the mass ratio of the common portland cement to the sand is 1:2-1:4; the mass of the cellulose ether accounts for 0.02-0.1% of the total mass of the common portland cement and the sand; the mass of the naphthalene formaldehyde water reducer accounts for 0.5-1.2% of total mass of the common portland cement and the sand; the mass of the re-dispersible latex powder is 0.05-0.4% of the total mass of the common portland cement and the sand; and the sand comprises 60-80wt% of tailing sand and the balance of natural sand. According to the embodiment of the tailing sand mortar dry blend, the use amount of the natural sand in the mortar is reduced, and the problem that the natural sand is in shortage is alleviated. In addition, the recycling reasonable application of the tailing sand is realized, and the preparation cost of the mortar is lowered.

The invention relates to a method for enhancing density of a SiC/SiC ceramic matrix composite. The method comprises the following steps: (1) a SiC/SiC ceramic matrix composite with a certain densification degree is immersed in slurry, in which an organic precursor and SiC powder are uniformly dispersed, and impregnation is carried out in an environment of 5-10 KPa vacuum degree for 20-50 min; (2) a material which has undergone vacuum impregnation is dried and the dried material undergoes cross-linking and curing; (3) the cross-linked and cured material undergoes pyrolysis treatment; and (4) the material which has undergone pyrolysis treatment further undergoes densification process in the atmosphere of a gaseous precursor containing Si and C elements by a chemical vapor infiltration technology while infiltration temperature is 850-1100 DEG C, pressure intensity is 10-20 KPa and infiltration time is 4-30 h. The method provided by the invention has advantages of simple operation, short densification time, good repeatability and high densification efficiency and has obvious advantages in the aspect of filling material voids. The method is a method with operability and development prospect.

The invention relates to negative pole lead paste for a lead-carbon super storage battery. The lead paste is prepared by mixing solid raw materials consisting of 1 to 93 percent of lead powder and 2 to 95 percent of lead-carbon composite material by using a paste mixing machine via a dry-mixing method and a wet-mixing method. The lead-carbon composite material of the negative pole lead paste for the lead-carbon super storage battery is prepared by the electro-deposition method and contains 25 to 55 weight parts of lead. The negative pole lead paste can increase the porosity and the utilization rate of negative pole active substances, improve the contraction state of a negative polar plate and enhance the bonding force between the lead paste and the polar plate as well as between the lead powder and the active carbon with high specific area, functions like a negative pole lead paste super capacitor under the condition of high carbon-added quantity, and improves the comprehensive performance of the storage battery.

The invention discloses a heat conduction graphite sheet and a manufacturing method thereof. The heat conduction graphite sheet consists of a polyimide film, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are positioned on the upper and lower surfaces of the polyimide film respectively and are formed by sintering graphite modifiers respectively; each graphite modifier consists of the following components in parts by weight: 20-25 parts of benzophenonetetracarboxylic dianhydride, 14-16 parts of benzenetetracarboxylic anhydride, 22-26 parts of diaminodiphenylmethane, 20-25 parts of dimethyl formamide, 8-10 parts of N-methyl pyrrolidinone, 1.8-2.5 parts of ethylene glycol and 2.5-3 parts of polydimethylsiloxane. The heat conduction performance of the heat conduction graphite sheet is improved in the vertical direction and the horizontal direction, local overheating is avoided, the uniformity of the heat conduction performance is realized, and meanwhile, the stability and reliability of the heat dissipation performance of a product are improved; the cost of the product is greatly reduced.

The present invention relates to a honeycomb type SCR denitration catalyst and a preparation method thereof, and belongs to the field of denitration catalysts. According to the present invention, diatomite and a molecular sieve are used to replace a large number of titanium dioxide as the carrier, such that the high cost problem of the existing catalyst is easily solved, and advantages of good chemical stability, good thermal stability, high activity, low cost, high anti-poisoning property, long service life and the like are provided; the rare earth oxide is added, such that the heat resistance of the catalyst can be improved, and the double effect of lattice structure stabilizing and volume shrinkage preventing can be provided; polyferrocene is the polymer reducing agent so as to easily improve the denitration rate of the denitration catalyst, wherein the denitration efficiency achieves more than or equal to 91%; and the honeycomb type SCR denitration catalyst preparation method has characteristics of simpleness, easy performing, and high production efficiency.

The invention discloses a titanium-silicon-carbon interface modified SiCf/SiC wave-absorbing composite material and a preparation method thereof. The preparation method comprises the steps: putting asilicon carbide fiber prefabricated body in a constant-temperature area of a CVD furnace, and depositing a titanium-silicon-carbon interface layer on the surface of silicon carbide fibers through a chemical vapor infiltration method within a proper temperature range; and soaking in slurry containing polycarbosilane and titanium silicon carbon to be impregnated; and preparing the ceramic matrix composite material through a precursor impregnation pyrolysis method (PIP). The SiCf/SiC composite material containing the Ti3SiC2 interface is prepared, the process is simple, the cost is low, the dielectric constant of the wave-absorbing composite material is effectively regulated and controlled, and a good wave-absorbing effect is achieved.

The invention relates to a rare-earth modified SCR denitrification catalyst and a preparation method therefor, and belongs to the field of denitrification catalysts. The rare-earth modified SCR denitrification catalyst takes aluminum oxide and nano titanium dioxide as carriers and takes rare-earth oxide and cross-linked chitosan resin as active centers; and the prepared catalyst is low in price, good in chemical and thermal stability, relatively high in activity, high in anti-poisoning performance and long in service life. The preparation method for the rare-earth modified low-temperature SCR denitrification catalyst is simple, feasible and high in production efficiency; and raw materials are easily available.

The invention discloses a pouring sealant for filling a gap between a charge and a shell of a warhead. The pouring sealant comprises hydroxyl-terminated polybutadiene, a curing agent, a plasticizer and a curing catalyst, wherein mol ratio of R=[NCO] in the curing agent to [OH] in the hydroxyl-terminated polybutadiene is 0.8-1.2, content of the plasticizer is 0-1.5 times that of the hydroxyl-terminated polybutadiene, and the content of the curing catalyst is 0-0.01wt% that of the hydroxyl-terminated polybutadiene. The pouring sealant disclosed by the invention can be used for effectively solving the problem of an inherent gap between the charge and the shell of the warhead of the conventional weapon, so that use safety performance of the warhead and penetration stability to a target are greatly improved; and by adopting the pouring sealant disclosed by the invention, fabricated charging can be carried out without prefabricating a grain, so that the warheads in various sizes and shapes are directly poured and moulded, the mass production capability is greatly improved and the charging process cost is greatly reduced.

The invention relates to a modified graphene oxide concrete crack repairing material and a preparation method thereof. According to the invention, a sulfydryl-terminated modified graphene oxide dispersion and alkynyl-terminated poly(hydroxypropyl acrylate) are firstly prepared; a large-sized monolithic graphene oxide dispersion is obtained through a clicking reaction of a sulfydryl group and an alkynyl group; and a concrete crack repairing material is prepared by mixing the large-sized monolithic graphene oxide dispersion with concrete components. According to the invention, the uniform large-sized monolithic graphene oxide dispersion is doped into the concrete crack repairing material to promote formation of a regular and uniform hydration product which is aggregated to form an intertwined and cross-linked compact structure, so the best repairing effect to concrete cracks is achieved; meanwhile, a functional waterborne polymer is introduced, so product performances are optimized; andthe modified graphene oxide concrete crack repairing material provided by the invention has the advantages of low cost, simple generation and repairing processes, good social benefits and economic benefits, and practicality.

The invention discloses a composite phase change energy storage material containing ionic liquid and a preparation method thereof and belongs to the technical field of phase change energy storage materials.The composite phase change material is formed by compounding a phase change energy storage material and a supporting material.The phase change energy storage material is formed by mixing one or two of 1-methyl imidazole dihydric phosphate and the propylamine formate ionic liquid and one or two of formate diethanolisopropanolamine, twain-80, polyethylene glycol 400 and fatty alcohol-polyoxyethylene ether WA, wherein the mass ratio of the ionic liquid is 90-95%.The supporting material is expanded graphite.The mass ratio of the phase change energy storage material to the expanded graphite is (6-10):1, and the phase change energy storage material is evenly adsorbed in holes of the expanded graphite.According to the composite phase change energy storage material containing the ionic liquid, the phase change temperature is about 46+/-2.0 DEG C, the phase change latent heat is large (150-180 KJ/Kg), the volume slightly expands, the preparation method is simple, cost is low, no volatility exists, emissions of waste water, waste gas and waste residues are avoided, and large-scale application and popularization are promoted.

The invention discloses a mesoporous nano-crystal tungsten trioxide electrochromic energy-storing film and a preparation method thereof. The method comprises the following steps: dissolving tungsten hexachloride and F127 into absolute ethanol, stirring and ageing to form a dip-coating solution; vertically inserting a conductive substrate into the dip-coating solution, and lifting at constant speeduntil the substrate completely departs from the solution to obtain a conductive substrate covered with a sol film; transferring the sol film to a drying oven to dry to form a gel film; performing high-temperature heat treatment on the gel film and removing a template agent F127 to obtain the mesoporous nano-crystal tungsten trioxide electrochromic energy-storing film. The film prepared by the preparation method has excellent electrochromic property and energy storage property and high cycling stability, can realize large-area preparation and can realize industrialized production easily.

The invention provides a preparation method of ultraviolet-polyurethane (UV-PU) dual-curing rein for 3D printing. The dual-curing resin contains pre-polymers with the structural formula as shown in the formula 1, the formula 2, the formula 3 and the formula 4, wherein R1 represents methyl or hydrogen, R2 and R3 represent alkylene, cycloalkylene and arylidene, R2 and R3 can be the same or different, and R4 is arylidene, alkylene and cycloalkylene. (The formulas are shown in the description). A low-viscosity polyurethane curing agent added into a UV-PU dual-curing system is equivalent to a diluent in the 3D printing process, and serves as a curing agent in the post-curing process, the polyurethane curing agent reacts with hydroxy in the low polymer for further curing, the connection strengthamong the layers of a printout is improved, and meanwhile, the mechanical performance and the thermal stability of the printout are enhanced. The dual-curing 3D printing resin has the advantages of high tensile strength, high breaking elongation, low shrinkage rate and low viscosity.

The invention relates to functional admixture for improving durability of concrete and cement products. The admixture is prepared by mixing a certain number of volume expansion carbonatite powder with alkali-aggregate reaction and an activator, namely grinding the volume expansion carbonatite powder with alkali-aggregate reaction into cement fineness, uniformly stirring with alkali-containing salt, and doping according to the mass of portland cement when the concrete and cement products are prepared. Tests prove that the functional admixture has the effects of reducing volume shrinkage of the concrete and cement products, reducing production cost of the concrete and cement products, effectively improving the compact degree and volume stability of the concrete and cement products, remarkably improving the durable performance of the concrete and cement products, improving the freeze thawing resistance, permeation resistance, carbonization resistance and other durable performances of the concrete and cement products, and prolonging the service lives of the concrete and cement products.

The invention discloses a manufacturing process of a heat-conductive film used for cell phones. The manufacturing process mainly includes the steps of: 1) pre-treating a thin film; 2) smearing a graphite modifier on the thin film; 3) pre-sintering the thin film; 4) calendering: calendering the pre-sintered carbonized film in the step 3) on a calender machine until the thickness of the film is 0.3-0.8 mm; 5) main sintering: heating the calendered polyimide thin film in the step 4) to 800-900 DEG C and maintaining the temperature for 30-60 min, and increasing the temperature to 900-1100 DEG C and maintaining the temperature for 10-30 min, and cooling the film to normal temperature to obtain the heat-conductive film. The manufacturing process is easy to carry out and is low in cost. The heat-conductive film is high in scraping strength and is high in heat conductivity. By uniformly smearing a layer of graphite modifier on both surfaces of the polyimide thin film, the heat conductive property in the vertical and horizontal directions is improved, so that heat dissipation uniformity of the film is achieved.

The invention relates to a denitration and demercuration catalyst and belongs to the field of environment-friendly catalysts. Components of the catalyst form a Mo-V-W/TiO2-Al2O3 system, the functions of denitration and demercuration are achieved at the same time under the effect of the active components Mo, V and W and the carrier TiO2-Al2O3, the structure of tail gas filtering and exhausting equipment can be effectively simplified, and environmental protection cost is reduced. In addition, the catalyst has high dust interference resisting capacity, and still can exert maximum filtering performance on the basis that no frequent halt is needed for removal of accumulated dust, and the catalyst is uniform in aging speed, high in filtering-out capacity and long in service life.

The invention discloses a production process of a high-performance ceramic-lined composite steel pipe, and relates to the field of steel pipes. The production process comprises the following steps: adding 2, 4-diaminotoluene into a three-neck flask, adding dried pyromellitic dianhydride to obtain a product B, uniformly mixing SiO2 and B4C, adding a silane coupling agent, carrying out ultrasonic dispersion to obtain a product C, and adding the product C into the product B to obtain an additive A. The problems that an existing ceramic steel material cannot meet the high-temperature-resistant requirement, cracks are likely to be generated in the impact and vibration process, raw materials are likely to be agglomerated, and the dispersity is poor are solved. When the ceramic steel pipe is impacted, SiO2 dispersed in a matrix can absorb impact energy of microcracks in the matrix and prevent the cracks from expanding, so that the mechanical property of a system is enhanced, B203 in a molten state can flow to the cracks of a ceramic interface to inhibit crack diffusion, and the ceramic interface is denser, therefore, the ceramic steel pipe is resistant to high temperature and not prone to cracks.

The invention discloses a red mud-based cementing material activator and a red mud-based goaf filling material. The red mud-based cementing material activator comprises the following components: desulfurization gypsum, fly ash, sodium carbonate, mirabilite, sodium silicate, sodium dihydrogen phosphate and bauxite. The red mud-based goaf filling material comprises a red mud-based cementing material activator, red mud, steel slag, cement, basalt fiber chopped yarns and sericite reinforced polypropylene master batches. According to the invention, red mud can be effectively excited by adopting the composite exciting agent disclosed by the invention, a filling material with stable structure and performance is formed, and the filling material has good flowability and compressive strength and can meet the filling requirements of a mine goaf; and compared with a traditional cementing material with cement as a main component, the red mud-based goaf filling material provided by the invention also has expansibility, can inhibit volume shrinkage in a cement hardening process, and can solve the problem of void in a current filling area.

The invention relates to the technical field of binder preparation, in particular to a preparation method of a heat stable type insulation binder. Epoxidized soybean oil can play a role in promoting the curing cross-linking of a high-temperature binder, the heat resistance of the binder is improved through adding the cross-linking degree, and meanwhile, the high-temperature binder keeps appropriate cohesion strength. Phosphoric acid is added into a raw material prepared from a phenolic resin, so that the volume shrinkage after high-temperature heat treatment is inhibited, a binding performanceis improved, and favorable thermal shock resistance is realized; through heating reaction, transition metal molybdenum is bonded into a phenolic resin molecule main chain so as to form an O-Mo-O structure connected with a benzene ring in a phenolic resin, so that the thermal decomposition temperature of the insulation binder is improved. Metallic oxide and metal salt are adopted as modified additives, and the voltage impact resistance of the insulation binder can be improved, so that the insulation binder has excellent heat stability and has a wide application prospect.