55results about How to "High open porosity" patented technology

A porous silicon nitride capillary core for a loop heat pipe is formed by firing raw materials including silicon nitride powder, a sintering aid and a pore forming agent, wherein the content of silicon nitride is not smaller than 90% by weight. The average grain size of the silicon nitride powder ranges from 0.1 micrometer to 10 micrometers, and the proportion of the alpha-phase silicon nitride is larger than 90%. Micropores included in the porous silicon nitride capillary core communicate with one another, the pore diameter of the micropores ranges from 0.5 micrometer to 5 micrometers, and the open porosity is larger than 50%. The porous silicon nitride capillary core is formed by sintering the silicon nitride powder, has good chemical stability and is resistant to corrosion of acid and alkali, decomposition of working media in the loop heat pipe can be effectively restrained, and the service life of the loop heat pipe is prolonged. Meanwhile, the porous silicon nitride capillary core is high in brittleness and good in machining performance, the surface micropores cannot be closed during outer wall finish machining, and the high open porosity of the capillary core is guaranteed.

The invention discloses a method for preparing a porous silicon-nitride ceramic material, which comprises the following steps of: stirring starch and water at the temperature of 40-90 DEG C to prepare pre-gelatinized starch; adding silicon nitride, a sintering aid, a bonding agent and a defoaming agent to the pre-gelatinized starch, and uniformly mixing through ball milling to prepare a mixed slurry; molding the mixed slurry through casting, and carrying gout degassing, curing, complete sample-freezing and freeze-drying processing to prepare a porous silicon-nitride ceramic blank body; removing organic volatile substances in the porous silicon-nitride ceramic blank body through heating; and sintering, and cooling a sample along with a furnace after sintering. The silicon-nitride ceramic material prepared by utilizing the preparation method disclosed by the invention has high open porosity (which can reach 60-90 percent) and low density (0.32-1.28g / <cm>3), the bending strength can be regulated within the range of 5-140MPa, and the application-performance requirements of materials in the fields of high-temperature gas and liquid filtration, purification and separation, chemical catalytic carriers and the like can be met.

The invention provides a lithium ion battery negative electrode slurry and a lithium ion battery negative electrode and battery prepared by using the negative electrode slurry. The lithium ion battery negative electrode slurry includes a negative active material, a binder, a solvent and a pore-forming agent. The pore-forming agent is selected from one or more azo compounds and / or sulfonyl hydrazide compounds. Without reducing the compaction density of the negative electrode piece, it can increase the porosity of the electrode piece, increase the uniformity of pore distribution, increase the effective conduction area of ​​lithium ions in the liquid phase, and improve the battery's performance while ensuring the high energy density of the battery. The rate performance and low-temperature performance are also improved, while the capacity is also improved.

The invention relates to the field of preparation of porous materials and provides a Ti 2 AlC porous material and preparation method thereof, comprising: uniformly mixing titanium powder, aluminum powder and dry activated carbon powder, the mass ratio of carbon powder to aluminum powder is 65-69:33, dry activated carbon powder and carbon powder and The mass ratio of the aluminum powder is 2-10:100; the mixed powder is pre-pressed to obtain a green body; the green body is heated to 190-210°C and kept for 1.8-2.2h; the temperature rise is less than 25°C / min Warm at a rate of 560-640°C, keep warm for 2.8-3.3h; then raise the temperature to 1280-1350°C at a heating rate of less than 25°C / min, and keep warm for 1-2h; cool to room temperature at a cooling rate of less than 18°C / min Ti 2 AlC porous material. The method is simple, and the obtained porous material has uniform pores, high porosity, and no problems such as pore-forming agent residue and green body deformation.

The invention discloses an antibacterial air filter membrane based on a polyacrylonitrile / graphene oxide / tea polyphenol compound. The antibacterial air filter membrane takes a non-woven fabric as a base material, and a composite membrane formed by the polyacrylonitrile / graphene oxide / tea polyphenol compound is deposited on the surface of the base material; the mass ratio of polyacrylonitrile to graphene oxide to tea polyphenol is (16 to 30) : (4 to 10) : (1 to 16). Meanwhile, the invention provides a corresponding preparation method. A microscopic structure of the antibacterial air filter membrane provided by the invention is as follows: polyacrylonitrile (PAN) nano-fibers form a staggered net-shaped structure aggregate, and the diameter is about 50 to 300nm; the graphene oxide (GO) is dispersed between the PAN fibers and between crossed points of the fibers; the diameter distribution of the GO is relatively great, and is in a micron grade; a structure that the nano-fibers is combinedwith a micron layered object is formed by the GO and the PAN. By adopting the structure disclosed by the invention, the thickness of the filter membrane can be improved and the porosity of the filtermembrane is kept; the filtering efficiency of the filter membrane is improved, and the pressure drop of the filter membrane is effectively kept; the filter membrane has the effect of filtering PM2.5 (Particulate Matter 2.5) in the air and has good antibacterial performance.

The invention discloses a preparation method of porous tantalum-based oxynitride ceramics, which comprises the following steps: S1, uniformly grinding tantalum-based oxynitride powder and then drying to obtain dry oxynitride powder; S2, placing the oxynitride dry powder in Carry out compression molding in a mold to obtain a sheet-shaped green body; S3, place the sheet-shaped green body vertically in a reaction vessel and set the sheet-shaped green body and the reaction container at intervals, and perform pressureless discharge plasma sintering under a protective atmosphere to obtain oxygen Nitride ceramic sheet; S4, decarbonizing the oxynitride ceramic sheet to obtain a porous tantalum-based oxynitride ceramic. The invention has the advantages of short sintering time, high heat transfer efficiency and high product purity.

The invention discloses a preparation method of a low-pressure and high-energy SiC semiconductor spark plug material. The method comprises the steps as follows: 1) 45%-70% of SiC powder, 5%-15% of ZrO2 powder, 10%-30% of Al2O3 powder and 10%-30% of composite oxide powder constituting a glass system are selected in the volume ratio, are uniformly mixed and pass a 200-mesh sieve to be stored for later use; 2) PVA with the solid content being 8% is added in the weight ratio of powder to PVA being 95:5 and manually and uniformly mixed, and the mixture passes a 80-mesh sieve and is pressed under the pressure of 80 MPa to form a green body; 3) the green body is placed in an air furnace to be sintered, heated to 450 DEG C at the heating rate of 5 DEG C / h and kept at the constant temperature for 12 h; 4) the green body with glue removed is placed in a vacuum sintering furnace, filled with Ar, heated to 1,600-1,800 DEG C at the heating rate of 5 DEG C / min to be sintered and kept at the constant temperature for 1-3 h. The prepared SiC semiconductor composite has excellent performance of low ignition voltage, high spark capacity, capability of avoiding effects of air pressure and environmental media, heat shock resistance, electric spark corrosion resistance, good extinguishment restart and high-attitude performance and the like.