439results about How to "Lower interface thermal resistance" patented technology

The invention relates to high-thermal conductivity lubricating oil and a preparation method thereof. The lubricating oil contains base oil and fluorinated graphene nanosheets, wherein the weight percent of content of the fluorinated graphene nanosheets is 0.01 to 10.0 %; and the preparation method comprises the steps as follows: firstly, preparing the fluorinated graphene nanosheets; and secondly, preparing the lubricating oil containing the fluorinated graphene nanosheets. The lubricating oil provided by the invention has the advantages of excellent antifriction effect, extremely high heat conduction capability and excellent stability and dispersibility.

The invention discloses a wavelength conversion device, a manufacture method thereof, a correlative light-emitting device, and a projection system. The wavelength conversion device comprises a light-emitting layer, a diffuse reflection layer, and a ceramic substrate which are successively stacked. The light-emitting layer comprises fluorescent powder and first glass powder. The volume fraction of the fluorescent powder to the light-emitting layer is from 14.1 to 38.7 percent. The diffuse reflection layer comprises white scattering particles and the first glass powder. The volume fraction of the white scattering particles to the diffuse reflection layer is from 22.0 to 62.9 percent. The coefficient of linear expansion of the ceramic substrate is greater than that of the first glass powder but less than those of the ceramic substrate and the white scattering particles. By adjustment of the volume fraction of the fluorescent powder in the light-emitting layer and the volume fraction of the white scattering particles in the diffuse reflection layer, the light-emitting layer and the diffuse reflection layer have high enough light-emitting efficiency and reflectivity and low internal thermal resistance and interface thermal resistance so as to achieve a beneficial effect of obtaining emergent light with high light-emitting efficiency.

The invention discloses a method for preparing metal reinforced uranium dioxide nuclear fuel pellets. The method mainly comprises two steps: firstly, preparing core-shell structure granules, namely performing low-temperature rapid pre-sintering on UO2 powder by using a Spark Plasma Sintering SPS technique, pelletizing, balling to obtain UO2 pellets, performing physical mixing on the UO2 pellets with metal (one of Mo, Cr, W and the like) micro powder to coat surfaces of the UO2 pellets by the metal micro powder, thereby obtaining metal coated uranium dioxide core-shell structure granules; secondly, preparing a nuclear fuel pellets, namely performing high-temperature liquidation on the metal powder on the surfaces of the UO2 pellets, thereby forming a micro cell structure continuous phase similar to a cytomembrane structure around the UO2 pellets, and obtaining the special metal reinforced UO2 nuclear fuel pellets with a UO2 substrate.

The invention discloses an aqueous heat dissipation coating and a preparation method thereof. The aqueous heat dissipation coating comprises an aqueous dispersoid containing a base resin, nanometer carbon material-coated boron nitride composite powder and optional auxiliary materials. The composite powder comprises boron nitride and a boron nitride-coating nanometer carbon material. The preparation method comprises carrying out grinding dispersion on the aqueous dispersoid containing a base resin and the optional auxiliary materials to obtain dispersive slurry, at least adding slowly the composite powder into the dispersive slurry, carrying out high speed stirring and carrying out standing defoaming. The nanometer carbon material-coated boron nitride composite powder is used as a coating filler so that excellent thermal conductivity of the nanometer carbon material and boron nitride and conductive infrared radiation characteristics of the nanometer carbon material are fully utilized, interface thermal resistance of the nanometer carbon material and boron nitride is reduced, and the coating has the advantages of high thermal conductivity, high infrared radiation rate, construction convenience, safety, environmental friendliness and wide application prospect.

A preparation method of W-plated diamond/aluminum composite relates to a preparation method of a metal-based composite. In order to solve the technical problem that since diamond and aluminum react to produce Al4C3, the obtained composite has poor interfacial adhesion and low heat conductivity. The method includes: first, coating the surface of diamond particles with W; second, preheating; third, infiltrating under pressure: applying a pressure of 10-15 Mpa with an intra-furnace press so that molten aluminum infiltrates the W-coated diamond particles, cooling at a speed of 100 DEG C/h to below 300 DEG C, relieving pressure, turning off a vacuum furnace, and demolding to obtain the W-plated diamond/aluminum composite; diamond is 55-65% in volume fraction, >/=98% in compactness, up to 622 W/(m.K) in heat conductivity, down to 7.08*10-6/K in thermal expansion coefficient and up to 304 Mpa in flexural strength. The invention belongs to the field of preparation of composites.

The invention provides a superhigh-thermal-conductivity continuous diamond skeleton reinforced composite material and a preparation method. The composite material is composed of a continuous diamond reinforced body and a base material. The continuous diamond reinforced body is prepared by depositing diamond films or diamond compound films on diamond particle preforms through a CVD method. The diamond compound films are graphene-wrapped diamond films or carbon-nanotube-wrapped diamond films. The base material is made of metal or polymer. Diamond powder is prepared into the performs, then the diamond films deposit on the surfaces of the performs through the CVD method, the diamond films are formed at the contact positions of adjacent diamond particles, and accordingly continuous heat conducting channels are formed between the isolated diamond particles. The deposited diamond films can serve as heat conducting bridges between the diamond particles, so that the dispersed diamond particles form a connection structure, accordingly high heat conductivity of diamond is fully used by the composite material, and the heat conductivity of the composite material is greatly improved.

The invention provides a preparation method of a thermal conductive film based on a graphene polyimide composite sponge precursor. The preparation method comprises the following steps that a grapheneoxide water solution is mixed with a polyimide precursor solution to obtain a graphene oxide/polyamide acid mixed solution, then the graphene oxide/polyamide acid mixed solution is frozen to obtain agraphene oxide/polyamide acid frozen sponge, a frozen drying method is adopted for drying to obtain a graphene oxide/polyamide acid composite sponge, the graphene oxide/polyamide acid composite spongeis placed in a hot pressing reactor, hot pressing oxidizing pre-processing is adopted and machinery pressuring is conducted to obtain a reduced graphene oxide/polyamide acid composite film, then vacuum hot processing and machinery pressuring are adopted to obtain a graphene/polyimide carbon film, then the graphene/polyimide carbon film is placed in a high-temperature graphitization furnace, and agradient temperature rising method is adopted to achieve graphitization of the carbon film. According to the technical scheme of the preparation method, the problem of dispersion of graphene is improved, the obtained film has a certain flexibility and high mechanical strength, and has better electrical and thermal conductivity, and the preparation technology is simple.

The invention relates to a single-mode high-power vertical cavity surface-emitting laser based on a SiC heat sink. Including N electrode, SiC substrate, N-type DBR, active region, oxidation limiting layer, P-type DBR, SiC (electrode + window + heat sink), SiO2 mask, solder. The present invention is characterized by adopting a flip-chip top-emitting structure. The light output window is made on the P-type DBR, and the top light output method is adopted, and the heat sink is also placed at the end of the P surface. SiC wafers have high thermal conductivity, high electrical conductivity and high transmittance of near-infrared light after being modified by special technology. The P electrode, light window and heat sink in the traditional structure are replaced by SiC wafers, and the functions of the three are combined into one. The SiC wafer is used as an electrode, and the circular P electrode of the traditional VCSEL is replaced by a planar electrode or a non-uniform grid electrode; the SiC wafer is used as a heat sink material, and the thermal expansion coefficient is similar to that of GaAs materials, and it is directly flip-chip connected to the P surface in the epitaxial wafer; The SiC wafer simultaneously becomes the light exit window.

The invention discloses heat dissipation interface material used for packaging of a high-power LED (light emitting diode) lamp and a preparation method thereof. The heat dissipation interface material is obtained by fully mixing flexible AB double-component condensed type room temperature curable silicone resin as matrix and dimethyl silicone oil and functionalized graphene microchip as thermally conductive filler. The unctionalized graphene microchip and silicone resin are mixed thoroughly on a two-roll mill to enable the functionalized graphene microchip to be dispersed in the silicon resin matrix uniformly so as to prepare the heat dissipation interface material with excellent performance. According to the heat dissipation interface material, the contact gap betweena LED chip module metal heat radiating base and a heat dissipation structure of a lamp shell is avoided and the interfacial thermal contact resistance is reduced, thereby forming highly efficient heat dissipation channel and accelerating heat transfer. The material provided by the invention has great benefit for the power, miniaturization, improvement of the reliability of product and increase of the life expectancy of the LED lamp.

The invention belongs to the technical field of a heat radiating plate, and particularly to a graphite copper foil composite heat radiating plate. The graphite copper foil composite heat radiating plate comprises a net-shaped copper foil, and a graphite film which is formed on at least one surface of the net-shaped copper foil through calendaring molding technology. The porosity of the net-shaped copper foil is 40-80%. The hole diameter is 0.002-2 mm. Compared with the prior art, the graphite copper foil composite heat radiating plate is advantageous in that the graphite film is formed on the net-shaped copper foil through calendaring molding technology; because no adhesive is used, interface thermal resistance is greatly reduced, and furthermore interlayer adhesive failure generated on the composite heat radiating plate is effectively prevented, thereby realizing excellent mechanical performance, high heat guiding performance and high heat radiating performance of the composite heat radiating plate, and greatly prolonging service life of the composite heat radiating plate. Furthermore, if porosity of the graphite copper foil composite heat radiating plate is overhigh, mechanical strength of the copper foil is reduced; and if porosity is overlow, combining strength between the copper foil and the graphite film is reduced. If the size of a mesh hole is overlarge, the graphite film cannot be closely combined with the copper foil; and if the size of the mesh hole is oversmall, insufficient combining force between the graphite film and the copper foil is caused.

The invention discloses a preparation method of a high-heat-conductivity diamond-copper composite, and relates to a preparation method of a composite. The problems that an existing preparation methodof diamond-copper composite cannot achieve net shape forming, high quality and large batch preparation of large-size sheet samples is solved. The preparation method comprises the steps that diamond powder is placed into a die and compacted to form a precast body, the precast body is hoisted to the lower end of a lifting rod on the upper portion inside an air pressure infiltration furnace, and a crucible containing copper alloy is placed below the precast body in the furnace; vacuumizing is carried out, heating and copper melting are carried out under protection of inert gas, the lifting rod descends, pressurization infiltration is carried out, pressure is kept for cooling, pressure is released, and finally the die is removed. The preparation method has the beneficial effects that high-efficiency mass production can be achieved, the mechanical property is high, the rate of finished products is high, large-size sheet samples can be prepared, sample heat conductivity is improved, the preparation cost is low, the content of impurities is low, and the forming die and the crucible can be repeatedly used. The preparation method is applicable to preparing the high-heat-conductivity diamond-copper composite and component.

The invention provides a graphene composite heat-conducting gasket which comprises a plurality of layers of graphene foam films arranged in the thickness direction and an adhesive, and the graphene foam films account for 50 wt.%-95 wt.%. The invention also provides a preparation method of the graphene composite heat-conducting gasket, wherein the preparation method comprises the steps: stacking the graphene foam films layer by layer and putting the graphene foam films into a mold, and applying pressure to tightly fit the films; uniformly coating the periphery of the graphene heat-conducting foam films subjected to pressure application with the adhesive, so as to completely coating a plurality of layers of graphene heat-conducting foam films into a block body; after the block body is cured and formed, cutting the block body into sheets along the stacking direction; dipping the cut sheets in dipping glue, taking out the sheets, and carrying out hot press molding on the taken-out sheets; and trimming the edge of the formed sheets, and removing an adhesive bonding area on the edge to obtain the graphene composite heat-conducting gasket. The heat-conducting gasket is low in density, high in heat conductivity in the thickness direction and low in heat resistance.

The invention discloses a high-heat-conduction diamond/copper composite material and a manufacturing method of the high-heat-conduction diamond/copper composite material, and belongs to the field of heat sink materials. A base material of the composite material is metal copper, and a reinforcement material of the composite material is diamond particles wrapped by titanium or chrome. The manufacturing method of the composite material includes the steps that the surfaces of the diamond particles with different particle diameters are plated with the titanium or the chrome with a magnetron sputtering method, a metal copper sheet is placed on the diamond particles for assembling, and the assembly is loaded into a pyrophylite mold after vacuum heat treatment is carried out; ultrahigh-pressure infiltration sintering is carried out under different-sintering-technology condition, and the high-heat-conduction diamond/copper composite material is manufactured. By means of the high-heat-conduction diamond/copper composite material and the manufacturing method, the problem of graphitization of diamond under the high temperature condition is solved, the density of the manufactured composite material is higher than 99%, the heat conductivity of the composite material is 685 W/(m.K), and the composite material can be used as a heat sink material in the fields of electronic packaging and the like.

The invention provides a pump-driven two-phase circuit device for heat dissipation of a high heat flux electronic device. Heat is collected and transported by using an endothermic process in evaporation and an exothermic process in condensation during a circulation flow process of a working medium. An evaporator for the circuit device comprises micro-channels and fins. In an area of high heat flux, the micro-channels are used to dissipate heat and increase a heat transfer coefficient of a partial area, while in an area of low heat flux, the fins are used. Due to great area difference between the micro-channel area and the fin area in the evaporator, when the working medium in the micro-channels enters the fin area, volume quickly expands and temperature of the working medium reduces, so as to help heat dissipation of the device in the fin area. By using different structures and with little resources, heat dissipation problems of devices with different powers are solved. The pump-driven two-phase circuit device for heat dissipation of the high heat flux electronic device can adapt to heat dissipation of electronic devices with different heat flux densities and can satisfy working requirements of electronic devices with a heat flux density of 50 W/cm<2> or above.

The embodiment of the invention provides a graphene/polyimide heat-conduction film and a preparation method thereof, which relate to the field of graphene. The preparation method of the graphene/polyimide heat conduction film mainly comprises the following steps: adding a polyamic acid nano-emulsion taking water as a medium into a graphene dispersion liquid taking water as a medium, and stirring to obtain graphene/polyamic acid composite slurry; and sequentially carrying out self-assembly film formation, imidization, carbonization and graphitization on the graphene/polyamic acid composite slurry. The preparation method is low in cost, environmentally friendly and suitable for mass production, the interface thermal resistance between graphene sheets in the heat conduction film can be reduced, and the heat conductivity is improved.

The invention provides a high-thermal-conductivity metal-based composite material with a graphene-modified interface and a preparation method of the high-thermal-conductivity metal-based composite material. The high-thermal-conductivity metal-based composite material with the graphene-modified interface comprises diamond and graphene-modified metal powder. The preparation method comprises the following steps that 1, annealing reduction is carried out on the metal powder so as to remove oxides on the surface; 2, the metal powder subjected to annealing reduction is coated with a solid carbon source or a gas carbon source, and high-temperature in-situ growth is carried out under the protection of hydrogen atmosphere to obtain graphene-coated metal powder; and 3, the graphene-coated metal powder is mixed with the diamond, and the high-thermal-conductivity metal-based composite material with the graphene-modified interface is prepared through hot-pressing sintering. According to the preparation method, the interface wettability between the metal matrix and the diamond particles is effectively improved, and the thermal resistance of the interface is reduced; and the high-thermal-conductivity graphene is introduced, so that the heat conductivity of the composite material is improved; and the high-thermal-conductivity metal-based composite material can be used as a material for the thermal management of a high-power-density device.