41results about How to "No obvious crack" patented technology

The invention discloses a preparation method of a flexible silica aerogel, relating to a silica aerogel. The invention provides the preparation method of the flexible silica aerogel, which takes methyl alkoxy-series silane as a silicon source precursor. The preparation method comprises the steps of mixing methyl trimethoxysilane or methyl trimethoxysilane, an anhydrous ethanol solution and water, further adding hydrochloric acid, regulating the pH value of the solution to 2-2.5, then adding ammonia water to obtain a sol, standing, then preparing a wet gel, further aging the wet gel, and then drying to prepare the flexible silica aerogel. The prepared flexible silica aerogel has the advantages of low density and high porosity, and simultaneously overcomes the shortcomings of poor integrity and great brittleness. According to the preparation method, the complicated steps of complex solvent exchange and gel modification are not required, so that the operation is simple and easy, the process is controllable, the cost is low, the period is short, and the continuous production can be realized.

The invention discloses a preparation technology of a bamboo columnar carbon with ultrahigh performance. The preparation technology comprises steps as follows: S1), selection of a raw material: the raw material is a bamboo carbonized material; S2), grinding and sieving: the raw material is sieved with a 325-mesh sieve, and the bamboo carbonized material of 325 meshes or fewer than 325 meshes is taken as one raw material; S3), powder grinding and material mixing: a small amount of petroleum asphalt is added to the bamboo carbonized material powder of 325 meshes or fewer than 325 meshes for powder grinding and mixing treatment, and a first mixture is obtained; S4), stirring: water is added to the first mixture for stirring; S5), pre-extrusion; S6), pressing and extrusion molding; S7), segmented drying; S8), carbonizing; S9), gradient type activation: the carbonized material is put in an activating furnace to be activated for 1-2 h at the temperature of 750-850 DEG C and then is activated for 1-3 h after the temperature is increased to 850-950 DEG C, and the bamboo columnar activated carbon is obtained. The bamboo columnar activated carbon prepared with the technology has the characteristics that strength, adsorbability and adsorption capacity are high, the ash content is low, adsorption speed and desorption speed are high, obvious cracks on the outer surface are avoided, the yield of follow-up carbonized and activated products is high and the like.

The invention discloses a special-shaped hole machining method and a special-shaped hole and relates to the technical field of laser machining. According to the method, femtosecond or picosecond or nanosecond pulse laser is adopted, and a mode completely based on scanning galvanometer filling machining is provided. The method comprises the steps that firstly, a through hole smaller than the hole diameter requirement is machined so that gasification objects and fusion objects formed in the machining process can be discharged and re-coagulation objects are prevented from depositing; then, roughmachining of a special-shaped hole diffusion section is conducted; then, the laser focusing position is adjusted, broaching is conducted on the basis of a dust discharge through hole, and a cylindrical through hole meeting the hole diameter requirement is machined; and finally, the focus position is precisely adjusted, and the diffusion section is machined layer by layer. By means of the special-shaped hole machining method and the special-shaped hole, heat-induced defects such as recasting layers, microcracks, coating collapse and the like generated in the process that in the prior art, a special-shaped hole is machined, and in particular, the special-shaped hole is machined in a workpiece with the surface coated with a thermal barrier coating are avoided; and in addition, the shape and dimension precision of the special-shaped hole are improved.

The invention discloses a preparation method of an alumina-zirconia composite coating on the surface of a high-thermal-conductivity carbon fiber. The preparation method is a sol-gel method, and comprises the processes of pretreatment of the surface of the carbon fiber; preparation of composite sol; coating and drying treatments of the pretreated carbon fiber after the pretreatment; and low temperature heat treatment of the carbon fiber coated with the composite sol. The carbon fiber coated with the alumina-zirconia composite coating was obtained through the processes. The crystal form of the composite coating prepared by the preparation method is the composite coating of gamma-Al2O3.t-ZrO2. According to the preparation method, the process is simple, the requirements on equipment and operating environment are low, the implementability is strong, raw materials are low in price and easy to obtain, the method is easy to realize and energy-saving and environmentally friendly, the compositecoating with complete coating and adjustable thickness can be prepared on the surface of the high-thermal-conductivity carbon fiber, and the oxidation resistance of the carbon fiber and the thermal conductivity of a carbon fiber reinforced aluminum-based composite material are improved.

The invention relates to a composite hydrogen resisting permeating layer on the surface of metal hydride and a preparation method thereof. The preparation method comprises the steps that through the dipping-pulling method, an organic silica solution or a mingled and modified organic silica solution coating is prepared on the surface of the metal hydride, or a modified organic silica solution coating is mingled on the surface of the metal hydride; after being subjected to segmental constant-temperature drying at 50-250 DEG C, a metal hydride matrix coated with the organic silica solution coating is sealed into a reacting container provided with a vacuumizing pipe and a breather pipe, the reacting container is arranged in a temperature-controlling heating furnace in a sealed mode, mixed gas containing carbon oxygen, nitrogen oxygen or carbon-nitrogen oxygen are introduced, and segmental constant-temperature sintering is conducted at 300-850 DEG C; after temperature-controlling cooling or furnace cooling, the composite hydrogen resisting permeating layer composed of the outer layer of an organic silica solution sintering layer and the inner layer of an in-situ reacting layer containing the carbon oxygen, the nitrogen oxygen or the carbon-nitrogen oxygen is prepared on the surface of the metal hydride matrix. The composite hydrogen resisting permeating layer is compact and continuous and tightly combined with the metal hydride matrix and has a hydrogen resisting permeating effect on the metal hydride matrix.

The invention discloses a straw utilization method. The utilization method comprises the following steps that firstly, straw is pretreated, wherein straw raw materials are cut up, the cut straw, a mixed bacteria solution and a synergist are mixed, clear water is added, and a ferment mixture is obtained after uniform stirring; secondly, the ferment straw is stacked; thirdly, the straw is fermented; fourthly, drying and crushing are conducted; fifthly, granulation is conducted, wherein straw fibers are conveyed into a hoop standard granulator, compression formation is conducted by means of circular dies and compression rollers, and rod-like straw particles are obtained; sixthly, cooling formation is conducted, wherein the compressed straw particles are fed into a cooling machine, and smoothly formed particles are obtained. According to the straw utilization method, the fermented straw can be directly used for production of fodder, methane fermentation, organic fertilizers and poultry feed, through the processes of drying and crushing, granulation and cooling formation, the surfaces of the straw particles are smooth and free of obvious cracks, the straw particles can be used as clean biomass combustion energy, and the utilization method is suitable for large-scale application and popularization.

Disclosed is a preparation method of a high-temperature adhesive suitable for a TC4 titanium-base alloy. The method comprises the following steps of dissolving phenolic resin and MK siloxane resin inisopropanol to prepare resin solutions respectively; mixing the two resin solutions to prepare a glue solution; carrying out mixing on nickel powder, titanium powder, silicon powder, aluminum powder,boron carbide powder and glass powder and then performing ball milling to prepare a uniform filler; and mixing the filler and the glue solution and executing other steps to prepare the adhesive. The preparation method has the advantages that the prepared high-temperature adhesive has the characteristics of being high in temperature resistance, up to 1200 DEG C, high in intermetallic compound generation amount, low in decomposition shrinkage rate, tight in connection with a bonded part, high in bonding strength and the like; and in an anaerobic high-temperature environment of 700-1200 DEG C, the adhesive can provide bonding strength of not less than 20 MPa for the TC4 titanium-based alloy, so that the application of the adhesive technology in high-temperature alloy connection and repair isgreatly improved.

The invention provides a preparation method of a geopolymer precursor and a product, application and a connection method of the geopolymer precursor. The preparation method of the geopolymer precursorcomprises the following steps that a1, potassium silicate, KOH and deionized water are taken to be made into an alkali activator, and the mass ratio of potassium silicate to KOH to deionized water is100: 4.9-6.5: 90-115; and a2, metakaolin and the alkali activator prepared in the step a1 are mixed and stirred uniformly to prepare a geopolymer precursor, and the mass ratio of metakaolin to the alkali activator is 70-100: 195-222. The preparation method of the geopolymer precursor provided by the technical scheme of the invention is simple and easy to operate, and the synthetic raw materials are low in cost; connection can be successful at a low temperature by using a drying oven, the connection cost is low, energy is saved, and the environment is protected; and when a ceramic aluminum piece is connected by using the product, the combination is firm without no obvious cracks, and the connection strength of the joint is relatively high.

The invention discloses a geopolymer coating layer suitable for a metal substrate and a preparation method of the geopolymer coating layer. The preparation method includes the steps of firstly, evenlymixing sodium silicate, NaOH and H2O, and drying to obtain a transparent alkali-activator; secondly, weighing geopolymer synthesizing raw materials and the alkali-activator, and mixing and stirring to obtain flowing-state geopolymer precursor; thirdly, spraying the geopolymer precursor to the surface of metal to obtain a geopolymer coating layer; thirdly, curing the obtained coating layer in theair to obtain the geopolymer coating layer. The preparation method has the advantages that the method is simple, easy to operate and cheap in raw materials; the real geopolymer coating layer uniform in thickness can be prepared, the geopolymer coating layer can be firmly combined with the metal substrate, and the cured coating layer is free of defects such as cracks; in addition, the geopolymer coating layer on the surface of the metal substrate can favorably improve the heat resistance and corrosion resistance of metal and is promising in industrial application prospect.

The invention designs and prepares a bismuth-containing biphase mixed conductor oxygen permeation membrane material with carbon dioxide resistance and high stability, and belongs to the technical field of inorganic functional ceramic manufacturing. The general formula of the bismuth-containing biphase mixed conductor oxygen permeation membrane material is Ce[0.9]Pr[0.1]O[2-delta]-Pr[0.6]Sr[0.4]Fe[1-x]Bi[x]O[3-delta] (CPO-PSF[1-x]B[x]O; x is equal to 0.01, 0.025, 0.05, 0.10, 0.15 or 0.20). The preparation method comprises the steps: firstly, preparing powder by a sol-gel one-pot method, calcining the powder in a muffle furnace at the temperature of 950 DEG C for 12 hours to obtain precursor powder, and then tabletting and sintering the precursor powder to obtain the required mixed conductor oxygen permeation membrane. The required bismuth-containing biphase mixed conductor oxygen permeation membrane material is obtained by regulating and controlling the ratio of the Bi element to the Fe element. The prepared oxygen permeation membrane material has good stability under purging of helium/carbon dioxide and other gases, and the oxygen permeation amount loss is small under the carbon dioxide corrosive atmosphere. The material can be used as a novel gas separation material and a carbon capture material to be applied to the high-temperature complex atmosphere oxygen industry, such as the fields of oxygen-enriched combustion, water decomposition, methane coupling and the like.

The invention belongs to the technical field of material protection, and particularly relates to a carbon material wide-temperature-range anti-oxidation anti-scouring composite ceramic coating and a preparation method thereof. The (ZrxHf< 1-x-y >Tay) B2-SiC multiphase ceramic coating with wide-temperature-range anti-oxidation and anti-scouring performance is prepared by adopting a reaction sintering method for the first time, the wide-temperature-range protection range is large, oxidation protection which can reach the high temperature of 800 DEG C and can reach 3000 DEG C or above can be provided, and at present, coatings with the wide-temperature-range protection performance are not reported. The method is low in cost and easy to operate, and the coating is compact in structure, controllable in thickness, high in binding force and excellent in thermal shock resistance. A (ZrxHf < 1-x-y > Tay) B2-SiC coating sample can bear oxidation corrosion for more than 1000 hours at the temperature of 800-1200 DEG C, and no weight loss exists; oxidation protection for more than 1200 hours can be provided in an oxidation environment of 1500 DEG C; ablation protection can be provided for at least 300 seconds under plasma high-temperature flames of 3000 DEG C; and after 50 times of thermal shock cycles at the room temperature of 1500 DEG C, the coating has no obvious cracks.

The invention discloses a method for detecting the quality of steelmaking auxiliary material dolomite. The method mainly solves the technical problem that the quality of existing dolomite cannot be accurately evaluated. The method for detecting the quality of steelmaking auxiliary material dolomite comprises the following steps: 1) preparing a sample, and crushing the weighed dolomite sample until the particle size of the crushed dolomite sample is 5-10mm; (2) taking a sample mineral phase structure picture; (3) detecting the ore phase structure of the sample; 4) judging the quality of the sample when the average grain size of the sample is <50[mu]m, the grain size standard deviation is <20 um, the sample is uniform in crystal grain distribution and free of obvious cracks among crystal grains, the sample being qualified, that is, the dolomite is not crushed or pulverized in the process of being calcined into the light-burned dolomite; otherwise, the sample quality being unqualified. The method is simple in process, easy and convenient to operate and convenient to implement; the detected quality of the limestone is accurate and reliable, and the detection cost is low.

The invention discloses a composite coating layer for eliminating chromium and VOCs pollution from the source. The composite coating layer comprises a conversion film layer and a coating surface layer; the conversion film layer is prepared from a surface pretreatment solution, and the surface pretreatment solution comprises: an organic compound A with an aromatic ring and at least two phenolic hydroxyl groups in molecules, or a hydrate thereof; an ionic compound B containing zirconium and/or titanium and fluorine elements; a mixed solution C containing manganese fluoride; and an inorganic saltD containing potassium ions or sodium ions; and the coating surface layer is an FEVE type fluorocarbon powder coating layer. The composite coating layer has excellent impact resistance, weather resistance and chemical reagent resistance, the pollution problem of heavy metal chromium and VOCs is eliminated from the source at the same time, and the composite coating layer is green and environmentally friendly. The invention further discloses a preparation method of the composite coating layer.

The invention provides aluminum alloy powder for selective laser melting forming. The aluminum alloy powder is prepared from, by mass, 3.7%-4.3% of Cu, 0.8%-1.2% of Li, 0.25%-0.8% of Mg, 0.25%-0.6% of Ag, 0.2%-1.0% of Sc, 0.1%-0.5% of Zr and the balance Al and unremovable impurity elements. Part of alloy samples obtained through the method are smooth in surface, free of obvious cracks and high in density, after heat treatment, the tensile strength is 580 MPa, the yield strength is 525 MPa, the ductility is 7%, and the satisfactory comprehensive performance of strength and toughness is achieved. The method has a wide application prospect in the field of aerospace.