40 results about "Kirkendall effect" patented technology

The invention discloses a hollow spherical NiMn2O4 lithium ion battery cathode material and a preparation method thereof, and belongs to the field of lithium ion battery electrode material technology. Particle size of the hollow spherical material is 1 to 3 micrometers; the spherical shell is made of NiMn2O4 nanometer crystals, and has a porous structure. The porous spherical shell is in favor of penetration of electrolyte, is capable of shortening diffusion distance of lithium ions, and possesses excellent electrochemistry cycling stability and rate capability. The preparation method is based on ''Kirkendall effect'', and the hollow spherical NiMn2O4 can be obtained directly by performing high temperature solid phase reaction. The preparation method comprises following steps: taking solid spherical MnCO3 as a precursor; roasting at a low temperature to obtain porous solid spherical manganese dioxide; and then roasting the porous solid spherical manganese dioxide with a nickel salt to obtain the hollow spherical spinel-type NiMn2O4 cathode material. The preparation method is simple in technologies, do not need a template, and is suitable for large-scaled production.

The invention provides a method for preparing a light Nb-Ti-Al based porous material, and belongs to the technical field of powder metallurgy porous materials. The method comprises the following process procedures: firstly, performing high energy ball milling on niobium powder, titanium powder, aluminum powder and element powder of other alloy elements to obtain mechanical alloyed powder; uniformly mixing Nb-Ti-Al based alloy powder with rotating electrode atomized niobium alloy powder through ball milling and forming at the pressure of 200-700 MPa to obtain a formed blank; performing vacuum pressure-free sintering and thermal treatment on the formed blank to obtain the Nb-Ti-Al based porous material. Pores are formed by virtue of the Kirkendall effect that pores are formed in a substrate because of partial diffusion of the Al element, and the strength of a porous body is improved with the combination of a sintered neck formed by the atomized alloy powder. The light Nb-Ti-Al based porous material is simple in preparation process, and the porous structure is easy to control.

The invention belongs to the field of high-entropy alloy materials and discloses an AlCrFeNiSiTi high-entropy alloy porous material and a preparation method thereof. The AlCrFeNiSiTi high-entropy alloy porous material provided by the invention comprises, by atomic percent, 10%-20% of Al, 10%-20% of Cr, 10%-20% of Fe, 10%-20% of Ni, 10%-20% of Si and 10%-20% of Ti. The AlCrFeNiSiTi high-entropy alloy porous material is prepared through an element powder reactive synthesis method. The principal element powder is adopted as a raw material, only a little lubricating agent needs to be added in thepreparation process, energy consumption is low, and the cost is low. Pores are generated through the Kirkendall effect caused by partial diffusion between elements. The controllability of the pore structure is good. There is no need to add a pore forming agent. No follow-up pore forming agent removal problem exists. The AlCrFeNiSiTi high-entropy alloy porous material and the preparation method thereof have the characteristics of short process and high performance.

The invention discloses a connection method of porous belly core and compact shell, the method is that: choose metal A and B powder in the range of negative 80 to positive 500 items, blend according to atom ratio 1/1, then put into a mixer to mix evenly, then package the A,B metal mixing powder into a compact tube made of metal A directly, after 2.5 to 5.0 MPa mould pressing and forming, weld in vacuum at 350 to 1200 DEG C. for 1 to 2 hours; wherein, the spreading speed of metal B in the metal A is large than that of the metal A in the metal B, the porous material is AB alloy, the compact material is metal A. With the method of powder metallurgy, the invention uses little alloy which can produce Kirkendall effect and welding swelling during welding, to finish welding spreading welding, and makes two parts connected into a whole body without air leakage and has good sealing performance, which can realize the integration forming of the porous material and the compact material, and has simple technics and lowers the production cost greatly.

The invention discloses a preparation method of a hollow structure Co3O4/CeO2 nanoparticle loaded nitrogen doped carbon nanofiber material and application thereof. The preparation method comprises thefollowing steps: 1) preparing a CO<2+>/Ce<3+>/PVP mixed sol; 2) electrospinning the CO2+/Ce3+/PVP mixed sol to obtain a solid carbon fiber film; and 3) preoxidizing the solid carbon fiber film in anair atmosphere of 200-300 DEG C, performing heat treatment in an inert atmosphere of 400-1000 DEG C with programmed temperature rise, and obtaining the hollow structure Co3O4/CeO2 nanoparticle loadednitrogen doped carbon nanofiber composite material by utilizing the Kirkendall effect of nano materials. The preparation method is low in cost, simple and universal. The prepared material is a one-dimensional carbon nanofiber material; hollow Co3O4/CeO2 composite nanoparticles are uniformly embedded in carbon nanofiber; and the material can be used as an electrolytic water oxygen evolution electrocatalytic material and has higher activity and excellent stability.

The invention provides polyethylene glycol vitamin E succinate modified tigecycline loading silver nanoparticles. First, under the stabilizing effect of polyethylene glycol vitamin E succinate, hollow silver nanoparticles are formed through kirkendall effect, and polyethylene glycol vitamin E succinate modified silver nanoparticles are synthesized, thus the stability of the hollow silver nanoparticles is improved, and toxicity caused by oxidation of the silver nanoparticles is reduced. An antibacterial drug tigecycline is effectively loaded by the hollow structure of polyethylene glycol vitamin E succinate modified tigecycline loading silver nanoparticles. With relatively small particle size, the nanoparticles can penetrate through the cell wall of bacteria, destroy cell membrane and enter cytoplasm; and through the synergistic antibacterial effect of silver nanoparticles and tigecycline, the minimal inhibitory concentration and minimal bactericidal concentration of a drug are remarkably reduced, and the drug resistance of escherichia coli against tigecycline is overcome. The silver nanoparticles can serve as a novel antibacterial nano material for preparing antibacterial drug-resistant drugs and is applied to the field of life science and pharmacy.

The invention discloses a silver-end electrode slurry for low-temperature sintering MLCC, which comprises 65.0 to 85.0 wt.% of silver powder, 2.0 to 6.0 wt.% of glass powder and 9.0 to 33.0 wt.% of anorganic carrier, wherein the weight ratio of nano silver powder to microcrystalline silver powder in the silver powder is (0.5 to 2.0) to 1; the ratio of the weight sum of the nano silver powder andthe microcrystalline silver powder to the weight of flake silver powder is (2.0 to 7.0) to 1; the glass powder comprises 38.0 to 55.0 wt.% of ZnO, 5.0 to 25.0 wt.% of SiO2, 5.0 to 40.0wt.% of B2O3, 5.0 to 20.0 wt.% of Al2O3, 1.0 to 6.0 wt.% of K2O and 2.0 to 6.0 wt.% of Cu2O. While the slurry ensures good compactness of the silver layer and can also solve the problem of a void generated at a connection place by Kirkendall effects in the case of high-temperature sintering of internal and external electrodes.

The invention a Ni-Al alloy honeycomb material. The Ni-Al alloy honeycomb material is characterized in that a core is a pure aluminium material or an aluminum alloy material, and is a linear or tube-shaped material specifically, and an outer layer of the Ni-Al alloy honeycomb material is a coating layer made from a pure nickel or nickel base alloy material; and the radial dimension range of a cross-sectional shape is 0.001 mm-10 mm, and the proportion of the diameter of the core linear material or the wall thickness of the core tube-shaped material to the thickness of the coating layer is 0.05 to 1. The invention also relates to a preparation method of the Ni-Al alloy honeycomb material. A hollow structure is formed by utilizing a Kirkendall effect that elements Ni and Al in a nickel-aluminum composite wire or tube are diffused, so that the Ni-Al alloy honeycomb material is obtained, the preparation method solves the problem that the high temperature mechanical properties and high temperature resistance corrosion properties of the conventional metal honeycomb material are universally low, and the preparation method is suitable for large-scale manufacture.

The invention provides a silicon-germanium solid solution and a preparation method and application thereof. According to the silicon-germanium solid solution and the preparation method and application thereof, a composite material containing a silicon precursor and a germanium precursor serves as a cathode, an inert electrode serves as an anode, and a melt containing CaCl2 serves as an electrolyte, so that silicon-germanium solid solution powder is obtained through electrolysis; or, a conductive substrate serves as a cathode, an inert electrode serves as an anode, and a melt containing a silicon precursor, a germanium precursor and CaCl2 serves as an electrolyte, so that a thin film or an array electrode material of the silicon-germanium solid solution on the conductive substrate is obtained through electrolysis. According to the single-step controllable template-free preparation method provided by the invention, the Kirkendall effect is utilized, in the electrolytic process, the diffusion rate of germanium is larger than that of silicon, and a vacancy is formed on one side of the germanium, so that a silicon-germanium solid solution nano hollow structure is obtained; volume change in the charging and discharging processes is effectively relieved, and the cycle performance and rate performance of a battery are significantly improved; and a template is not needed, operation is convenient, and the silicon-germanium solid solution is suitable for large-scale industrial production.

The invention discloses a nickel-cobalt-manganese ternary metal sulfide hollow structure material and preparation and application thereof, and belongs to the field of supercapacitor electrode materials. The preparation method comprises the following steps: by taking ZIF-67 as a template reactant and a cobalt source, carrying out ion exchange on the ZIF-67, nickel salt and manganese salt under a hydrothermal condition, carrying out an H+ etching effect generated by hydrolysis of metal salt and a Kirkendall effect to prepare a NiCoMn-OH hollow structure material; and the hollow structure material and thioacetamide are subjected to solvothermal reaction to prepare the nickel-cobalt-manganese ternary metal sulfide hollow structure material. The nickel-cobalt-manganese ternary metal sulfide hollow structure material prepared by the method has very high specific surface area and specific capacitance, and the specific capacitance can reach 2098.2 F/g when the nickel-cobalt-manganese ternary metal sulfide hollow structure material is used as an electrode material of a supercapacitor.

The invention provides a porous ultrathin grinding wheel for chip cutting and a preparation method thereof. The ultrathin grinding wheel is composed of a super-hard abrasive and a metal-based matrix, the super-hard abrasive comprises diamond and cubic boron nitride, the metal-based matrix is a Ti-Al-based alloy, and a porous structure on the ultrathin grinding wheel is generated by utilizing a Kirkendall effect reaction caused by a diffusion rate difference between Ti/Al elements. The preparation method comprises the steps of carrying out material preparation, carrying out cold press molding, carrying out sintering molding and carrying out machining, wherein the sintering molding is composed of two sintering procedures of pore forming and performance adjusting, the sintering conditions of the pore forming procedure are 600-700 DEG C and 10-240 min, and the sintering conditions of the performance adjusting procedure are 750-1100 DEG C and 5-120 min. According to the porous ultrathin grinding wheel for chip cutting and the preparation method thereof, chemical bonding is achieved through mutual diffusion of Ti elements and the super-hard abrasive, so that the holding force of abrasive particles is improved, and the ultrathin grinding wheel can be further thinned; and the self-sharpening capacity of the ultrathin grinding wheel is improved by introducing the porous structure through the Kirkendall effect between the Ti/Al elements, so that the cutting quality of a chip is improved, and materials such as a pore forming agent do not need to be added, so that the production cost is reduced.

The invention provides a porous nanotube with a rough surface and a dual-element Pt/PdPt/Pt interlayer tube wall and a preparation method of the porous nanotube. The Kirkendall effect is used for enabling platinum ions to generate a nucleation phenomenon on the surface of a palladium nanowire, internal palladium is gradually removed through gaps of a deposition layer, and then the hollow PdPt nanotube with the outer diameter being 8.6 nm and the wall thickness being about 2.2 nm is formed; the nanotube is further processed to form an interlayer structure with a tube wall element of Pt/PdPt/Pt. According to the product PdPt nanotube, the platinum element can be fully exposed on the inner side and the outer side of the nanotube wall, the utilization rate of platinum in the material is greatly increased, the tube wall interlayer contains the PdPt double elements, and the catalytic reaction activity is greatly improved through the stress and strain effect between the double metals. When the catalyst is used as a fuel cell cathode reaction catalyst, the reaction activity of the catalyst is greatly improved in an oxygen reduction reaction, the active specific surface area ECSA of the catalyst is 1.46 times that of commercial Pt/C sold in the market, the mass activity (MA) of the catalyst is 14.3 times that of the commercial Pt/C, and the actual specific activity (SA) of the catalyst is 9.64 times that of the commercial Pt/C.

The invention discloses a hollow carbon-coated copper oxide nanoparticle catalyst and a preparation method and application thereof. The preparation method comprises the steps: in an inert atmosphere, calcining copper metal organic framework powder for the first time, and obtaining a red product; carrying out secondary calcination treatment on the red product in an air atmosphere to obtain a calcined product; and grinding and sieving the calcined product to obtain the hollow carbon-coated copper oxide nanoparticle catalyst. The hollow carbon-coated copper oxide nano-particle catalyst with rich oxygen vacancies is effectively synthesized by utilizing the Kirkendall effect, due to the unique hollow structure and the rich oxygen vacancies, the maximum Faraday efficiency of ammonia of the catalyst is 94.2% under the potential of -0.2 V Vs RHE, the generation rate of ammonia reaches 487.8 mmol g<cat><-1> h<-1>, and the maximum Faraday efficiency of the catalyst is 94.2% under the potential of-0.2 V Vs RHE, and is about 2.4 times of the conversion rate of ammonia in the Haber-Bosch reaction.

The invention discloses a method for preparing a hollow/mesoporous nano structure material by adjusting the Kirkendall effect through a magnetic field. In the process that a hollow/mesoporous nano structure material is prepared through the Kirkendall effect, a hydrothermal reaction step is implemented under an external magnetic field condition. Due to an external magnetic field, the time that a solid nano structure material is transformed into the hollow/mesoporous nano structure material is greatly shortened at a relatively low temperature by virtue of the Kirkendall effect, so that great benefit values are made since the reaction preparation cost is reduced, and current development themes of energy conservation and environment protection are met.

The invention discloses hollow silicon dioxide as well as a preparation method and application thereof. The preparation method comprises the following steps: 1) dispersing monatomic silicon powder in a liquid-phase reaction system to obtain a silicon powder dispersion liquid; and 2) slowly dropwise adding ammonia water into the silicon powder dispersion liquid obtained in the step 1) until the pH value of the reaction system is 10-10.4, and then carrying out hydrothermal reaction. The hollow silicon dioxide is prepared from monatomic silicon powder through interface diffusion, preliminary oxidation and hollowing of silicon atoms and hydroxyl groups in a hydrothermal reaction. The hollow silicon dioxide prepared by utilizing the Kirkendall effect at the interface is compact in surface, has the characteristics of low stress, high mechanical strength and low moisture absorption, and can improve the reliability and reduce the dielectric constant and dielectric loss when being used as a filler of an electronic packaging material; the hollow silicon dioxide provided by the invention has the advantages of simple preparation method, no need of multi-step reaction, low cost and higher application value.

The invention provides a porous Cu-Sn-based ultra-thin grinding wheel for chip dicing and a preparation method thereof. According to the porous Cu-Sn-based ultra-thin grinding wheel, a metal matrix tire of the ultra-thin grinding wheel is Cu-Sn-Ti alloy, and a porous structure of the ultra-thin grinding wheel is generated by utilizing a Kirkendall effect caused by a diffusion rate difference between Cu/Sn elements. The preparation method comprises the steps of material preparation, cold press molding, brazing molding and machining, wherein the brazing molding process comprises two heating procedures of pore forming and active brazing, the parameters of the pore forming procedure are 200-250 DEG C and 30-240 minutes, and the parameters of the active brazing process are 650-950 DEG C and 5-100 minutes. According to the porous Cu-Sn-based ultra-thin grinding wheel and the preparation method thereof, a metal bonding agent and a super-hard abrasive material undergo chemical metallurgical reaction by utilizing an active brazing technology, so that the holding force of abrasive particles is improved, and the ultra-thin grinding wheel can be further thinned; and the self-sharpening capacity of the ultra-thin grinding wheel is improved by introducing the porous structure through the Kirkendall effect between the Cu/Sn elements, so that the chip dicing quality is improved, and in addition, materials such as a pore forming agent do not need to be added, so that the production cost is lowered.