57results about How to "Controllable coefficient of thermal expansion" patented technology

The invention discloses a preparation method of a nanometer carbon fiber-copper composite material, which belongs to the technical field of preparation of electronic component composite materials. The method comprises the following steps: plating nanometer carbon fibers with a certain volume fraction of copper or copper-nickel alloy by chemical plating or electroplating, reducing the metalized nanometer carbon fibers in hydrogen, then preparing a nanometer carbon fiber-copper composite material blank by hot isostatic pressing or discharge plasma sintering, finally performing hot rolling cogging, and performing cold rolling to realize oriented arrangement of the nanometer carbon fibers, so as to prepare the nanometer carbon fiber-copper composite material. The prepared nanometer carbon fiber composite material has a density lower than that of copper, is adjustable in thermal expansion coefficient, is high in thermal conductivity in the parallel fiber direction, and is widely used in microelectronic packaging, laser diodes, IGBT and semiconductors, radiating fins, and cover plates.

The invention discloses a diamond particle reinforced metal matrix composite material and a preparation method and application thereof. The preparation method comprises the steps of 1, preparing an interface layer; 2, preparing a metal layer; 3, premolding; and 4, carrying out densification treatment. According to the diamond particle reinforced metal matrix composite material and the preparationmethod and application thereof, the adopted sintering of a two-step solid-phase method combined with the premolding and densification treatment is characterized by complementing for each other, fostering strengths and circumventing weaknesses, so that the the characteristic that the solid-phase sintering method capable of preparing a material with smaller particle size is retained, the size of thematerial prepared in a single batch is larger, the thickness reaches the centimeter level or a higher level, the production efficiency is higher, and the cost is greatly reduced; the prepared material has higher thermal conductivity, adjustable thermal expansion coefficient and better uniformity and reliability, and can be directly cut for processing by an electric spark wire; and meanwhile, thepremolding before the densification treatment can solve the problem that a bag sintered by directly adopting hot isostatic pressing is deformed too much so as to result in too much waste of the material, and the material utilization rate is higher.

The invention relates to a soft magnetic composite material and a preparation method thereof, relating to a soft magnetic material and the preparation method thereof, and aiming to solve the problem that the coefficients of thermal expansion of an inorganic insulating layer and magnetic powder greatly differs from each other and the coefficient of thermal expansion of the inorganic insulating layer can not be changed. The soft magnetic composite material consists of magnetic powder, a silicon dioxide layer coated by the magnetic powder and a glass layer coated outside the silicon dioxide layer. The preparation method comprises the following steps: firstly, pre-treating the magnetic powder; secondly, coating the silicon dioxide layer on the surface of the magnetic powder; thirdly, coating the glass layer outside the silicon dioxide layer; fourthly, preparing a blank material of the soft magnetic composite material; and fifthly, preparing the soft magnetic composite material. The soft magnetic composite material is applied to the fields of switch magnetic resistance, resonance inductance, anti-lock brake sensors, electromagnetic drive devices, brushless direct current motors, rotating machinery and low-frequency filters.

The invention relates to a preparation method of a microchannel heat sink for high-heat flux heat dissipation. The method includes the following steps that: a) materials are selected; b) a microchannel is made inside a plate; c) three-dimensional microchannel deformation-free modeling is performed; d ) and a metal frame, a ceramic frame, an outer lead, an IC device, a sensor and a heater are integrated on an active microchannel heat sink, so that system miniaturization can be realized, mechanical support and environmental protection are provided for a chip and an internal circuit, and an input and output function is realized for the chip and the internal circuit. The thermal expansion coefficient of the product is adjustable; and heat generated by devices or a system can be taken away from the heat sink through a high-thermal conductivity medium, the temperature of the surface of the heat sink can be decreased as much as possible and remain constant. The microchannel heat sink has the advantages of small size, large heat dissipation area, good solderability and high stability, and can meet the requirement of high-power density heat dissipation, and can be in sealed connection with other components or parts.

The invention relates to a silicon carbide and silicon particle reinforced aluminum-copper based composite material and a preparation method thereof, and belongs to the field of the particle reinforced metal based composite material. The composite material is composed of the components by the weight percentage: 15-25 wt.% of silicon carbide, 45-50 wt.% of silicon and 25-40wt.% of an aluminum-copper alloy; the silicon carbide and silicon particles as a reinforcement phase are uniformly distributed in the aluminum-copper alloy matrix, and the aluminum-copper alloy matrix forms a three-dimensional reticular structure. A powder metallurgy method is used for preparation. The obtained aluminum based composite material has uniform structure, is fully dense, has the comprehensive performance of light weight, low expansion, high modulus, high strength, resistance to space radiation environment, easy processing and the like, is suitable for use in space environments, and can be used as related component materials in the aviation and aerospace fields.

The invention discloses a thermal expansion coefficient adjustable Cu heat sink and a preparation method thereof, belonging to the technical field of semiconductor laser unit chip packaging, and solving the problems that the thermal expansion coefficient of a metal heat sink is high, the heat conductivity coefficients of most ceramic heat sinks are poor, and the ceramic heat sinks with low expansion and high heat conductivity properties are high in price and are difficult to process in the prior art. The heat sink consists of Cu being 20-80vol.% and ceramic particles being 20-80vol.%, wherein the ceramic particles are TiB2, TiC, ZrB2 or ZrC. The thermal expansion coefficient of the Cu heat sink can be adjustable in the range of 5.91*10<-6>/K to 13.44*10<-6>/K by adjusting the content of the ceramic particles, and further the thermal expansion coefficient of the Cu heat sink is matched with that of a semiconductor laser unit chip; the internal stress for welding is reduced; the reliability of the semiconductor laser unit is improved; the service life of the semiconductor laser unit is prolonged; the thermal expansion coefficient adjustable Cu heat sink and the preparation method thereof are applicable to heat dissipation and packaging of semiconductor laser unit chips.

The invention relates to a soft magnetic composite material taking glass powder as a coating layer and a preparation method of the soft magnetic composite material, relating to the soft magnetic material and the preparation method thereof. In the invention, the problem that in the traditional soft magnetic composite material of an inorganic coating layer, excellent mechanical property of the soft magnetic composite material and excellent magnetic property of the soft magnetic composite material resulting from an annealing mean can not coexist, and the difference of coefficients of thermal expansion between an inorganic insulating layer and magnetic powder is greater is solved. The soft magnetic composite material taking the glass powder as the coating layer consists of the magnetic powder, a silicon dioxide layer coated by the magnetic powder and a glass powder layer coated outside the silicon dioxide layer. The preparation method comprises the following steps: firstly, pre-treating the magnetic powder; secondly, coating the silicon dioxide layer on the surface of the magnetic powder; thirdly, coating the glass powder layer outside the silicon dioxide layer; fourthly, preparing a blank material; and fifthly, annealing the blank material. The soft magnetic composite material taking the glass powder as the coating layer and the preparation method of the soft magnetic composite material are applied to the fields of switch magnetic resistance, resonance inductance, anti-lock brake sensors, electromagnetic driving devices, brushless direct current motors, rotating machinery and low-frequency filters.

The invention belongs to the technical field of composite materials, and specifically relates to a SiC/Al2(WO4)3/Al composite material with an adjustable thermal expansion. Al is used as a matrix; a low thermal expansion material SiC is used as a reinforcement; meanwhile, a certain amount of Al2(WO4)3 powder is added in for achieving a reduction of the thermal expansion coefficient. Al2(WO4)3 is a negative thermal expansion material that is able to resist a high temperature and is stable in property. On one aspect, Al2(WO4)3 is added in for reducing the thermal expansion coefficient of the original SiC/Al composite material; on the other aspect, Al2(WO4)3 is added in for reducing the content of the highly hard abrasive SiC and increasing the subsequent processing performance of the composite material. The SiC/Al2(WO4)3/Al composite material with the adjustable thermal expansion is prepared by a powder metallurgy technology. The thermal expansion coefficient of the SiC/Al2(WO4)3/Al composite material is significantly lower than that of the SiC/Al composite material. Accordingly, the requirement to the thermal expansion coefficient of electronic packaging materials is met better.

The invention provides a metal-based composite material and a preparation method and application thereof. According to the metal-based composite material disclosed by the invention, the reinforcement particles are distributed in the metal matrix in a gradient manner, so that the metal-based composite material has excellent comprehensive performance, including relatively high heat conductivity coefficient, adjustable thermal expansion coefficient, relatively high hardness, relatively low density and good and long-term stable performance, and is an ideal heat dissipation packaging material. According to the metal-based composite material, in the metal-based composite material, the reinforcement particles are distributed in the metal matrix in a gradient mode, the gradient material can relieve the internal thermal stress of the material under the cyclic change of the high-temperature and low-temperature environment, and the failure of electronic components due to the thermal problem can be solved. For example, a silicon carbide aluminum-based composite material (SiCp/Al) with a high volume fraction ratio has excellent comprehensive performance, including relatively high heat conductivity coefficient, adjustable thermal expansion coefficient, relatively high hardness and relatively low density, and is an ideal material in the field of electronic packaging.

The invention relates to the field of high-molecular materials, and concretely relates to a method for preparing a polyimide film. The method comprises the following steps: (1) selecting at least one diamine monomer and at least one dianhydride monomer, and adjusting the molar ratio of the diamine monomer to the dianhydride monomer according to a calculating formula in order to obtain the moles of the diamine monomer and the dianhydride monomer when a target thermal expansion coefficient is achieved; and (2) reacting the selected diamine and dianhydride monomers in a solvent according to the above moles to obtain a polyamic acid solution, and performing film formation and imidization on the polyamic acid solution to obtain the polyimide film. The method of the invention adopts a structure containing a hydrogen bond, the dianhydride and diamine monomers are selected, and the ratio of the two monomers is adjusted to effectively adjust the thermal expansion coefficient of the polyimide film, so the obtained polyimide film has excellent mechanical performances and high-temperature application performances, and has the thermal expansion coefficient matching with an adhered substrate to avoid the deformation and curling of the polyimide film due to the difference in thermal expansion coefficients.

The invention discloses a high-temperature-resistant inorganic adhesive and a preparation method thereof. The high-temperature-resistant inorganic adhesive contains sodium water glass, meta-kaolin, silicon phosphate, styrene-acrylic emulsion, magnesium oxide, polyacrylic acid and spherical aluminum oxide. The high-temperature-resistant inorganic adhesive provided by the invention has the advantages of low curing temperature, safety and environmental protection, can tolerate the high temperature of 300 DEG C or above for a long time, can have good adhesive property with ceramics in the range of normal temperature to 300 DEG C, has good water resistance and acid and alkali resistance, has a compact cured body structure, and can isolate air and moisture permeation.

The invention discloses a uranium dioxide-based fuel pellet with an adjustable thermal expansion coefficient and enhanced thermal conductivity, and a preparation method thereof. According to the preparation method, metal beryllium (Be) with high thermal conductivity and high thermal expansion coefficient and metal molybdenum (Mo) with high thermal conductivity and a low thermal expansion coefficient are added into a uranium dioxide pellet matrix, the component ratio of Be/Mo is regulated and controlled, the densified fuel pellet is sintered at a high temperature, so that the thermal conductivity of the uranium dioxide fuel pellet is enhanced, the thermal expansion coefficient of the uranium dioxide pellet is adjusted, the residual thermal stress of the fuel pellet is reduced, and the service cycle of the fuel pellet is prolonged so as to meet the harsh reactor work design requirements of the cladding-pellet fuel element under the normal work condition and the accident work condition ofthe reactor, improve the safety and the economy of the existing commercial pressurized water reactor, effectively delay the closing time of the air gap between the cladding and the fuel pellet underthe accident condition and delay the mechanical interaction between the fuel and the cladding to substantially improve the safety margin of the reactor under the accident condition.

The invention discloses a preparation method of an aluminum-silicon composite material for electronic packaging. The preparation method is characterized by comprising the following steps of S1, preparing pure aluminum and pure silicon, and smelting aluminum-silicon alloy to obtain an aluminum-silicon alloy melt; S2, performing gas atomization powder preparation on the aluminum-silicon alloy melt,and sieving powder to obtain aluminum-silicon alloy powder; S3, performing cold briquetting on the aluminum-silicon alloy powder to obtain an aluminum-silicon alloy green compact; S4, performing semi-solid forming on the aluminum-silicon alloy green compact after cold pressing to obtain an aluminum-silicon composite material; and S5, performing annealing treatment on the aluminum-silicon compositematerial. The aluminum-silicon composite material for electronic packaging prepared by the method is fine in silicon phase size, is passivated in silicon phase corner angle, is uniformly distributedin an aluminum matrix and has good microstructure characteristics and comprehensive properties.

The invention relates to a metal-based composite material device based on gas-liquid phase change and a preparation method thereof. The composite material device comprises a metal tube shell forming aclosed cavity, and a porous medium layer arranged in the middle of the metal tube shell and soaked with a liquid working medium, wherein the porous medium layer is arranged in the metal tube shell, the liquid filling port is arranged at one end outside the metal tube shell and connected with the porous medium layer, a heat source device can be arranged at the other end outside the metal tube shell, the liquid working medium can generate gas-liquid phase change after being heated, and the porous medium layer divides a closed cavity of the metal tube shell into two steam channels. Compared withthe prior art, the invention effectively solves the problem that the traditional single metal or ceramic heat dissipation material is difficult to consider the requirements of high thermal conductivity, controllable thermal expansion coefficient and high comprehensive mechanical properties at the same time, and provides a new direction for the development of high-power density devices.

The embodiment of the invention provides a thermoplastic composite material taking engineering plastic as a matrix. The composite material is prepared from the following components in parts by weight:20-80 parts of thermoplastic engineering plastic, 20-80 parts of functional filler, 1-10 parts of coupling agent, 0.5-1 part of antioxidant and 0.5-2 parts of other auxiliaries, the functional filleris prepared from 0-80 parts of negative thermal expansion material and 0-80 parts of silicon dioxide microbeads, and the total weight part of the thermoplastic engineering plastic and the functionalfiller is 100 parts. The thermoplastic composite material has an extremely low linear thermal expansion coefficient, good heat resistance and high stability, can be used for preparing high-precision structural parts such as optical communication and 5G equipment, and improves the long-term operation precision of precision equipment products. The embodiment of the invention also provides a preparation method of the composite material and a high-precision plastic part.