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132results about How to "Small coefficient of thermal expansion" patented technology

A kind of preparation method of fiber reinforced silicon carbide ceramic matrix composite material

The invention proposes a method for preparing a fiber-reinforced silicon carbide ceramic-based composite material, which includes the following steps: using chemical vapor infiltration to deposit one or more layers of continuous interface phases on the fibers of the fiber preform; using a ceramic organic precursor solution to impregnate and deposit The fiber preform with interfacial phase; the impregnated fiber preform is cracked in a vacuum furnace to form a silicon carbide-based composite material matrix; the fiber preform with stable shape obtained in the above steps is removed from the tooling to obtain a molded body; After the body is impregnated with the organic precursor solution and dried, it is cracked in a vacuum furnace and transformed into a ceramic matrix; the above steps are repeated 6 to 8 times to obtain a relatively dense shaped body; the obtained material is further densified by chemical vapor infiltration. The above method is conducive to the preparation of fiber-reinforced ceramic matrix composite materials or components with complex shapes, and the obtained materials have good thermal shock resistance, and at the same time, the ceramic matrix has the characteristics of high bonding strength.
Owner:SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

Heat resistance concrete and preparation method thereof

InactiveCN102531487AGood cohesionSmall coefficient of thermal expansionDamp environmentCoal
The invention relates to heat resistance concrete and a preparation method thereof. The heat resistance concrete is prepared from the following raw materials comprising portland cement, coal ash, basalt with the particle size of between 20 and 40 millimeters, gravels with the continuous level of between 5 and 25, medium-coarse sand, a corrosion inhibitor, a water reducing agent, water and the like. The preparation method comprises the following steps of: selecting the raw materials; mechanically stirring for 2 to 3 minutes; after the raw materials are stirred and mixed uniformly, hierarchically pouring, wherein each layer is 25 to 30 centimeters thick; and after pouring, maintaining for at least 7 days in a damp environment with temperature of between 15 and 25 DEG C. The concrete prepared by stirring the raw materials according to the proportions has high peaceability and favorable viscosity; the performance of the mixture meets the construction requirement; the prepared concrete has the heat resistance of between 700 and 1,200 DEG C, the strength level of between C25 and C30, the high temperature strength of between 3.5 and 20 Mpa and the slumps of between 160 and 180 centimeters, can be pumped for construction, and is suitable for engineering with relatively high temperature and zero acid-base erosion.
Owner:PINGDINGSHAN HENGJI CONCRETE

Preparation method of filled-type thermally conductive silicone rubber composite material

The invention discloses a preparation method of a filled-type thermally conductive silicone rubber composite material. The processing steps of the method are as follows: 1) using alcohol solution to mix carbon-encapsulated copper nanoparticles evenly, and then drying the nanoparticles to prepare dry powder; 2) adding the raw silicone rubber onto a roller, after the raw rubber covers the roller, adding carbon-encapsulated copper nanoparticles dry powder and hydroxy silicone oil in sequence in accordance with the formulation design amounts; mixing the dry powder and the hydroxy silicone oil on the roller repeatedly until being uniform, then adding a vulcanizing agent, and then mixing the mixture uniformly, thin-passing a lower sheet to obtain the silicon rubber compound; 3) putting mixed silicone rubber into a mold, carrying out first vulcanization after cold pressing and mold filling; 4) putting a vulcanization-molded sample on a glass cloth and carrying out post vulcanization on the sample in an air dry oven to obtain finished products. The invention mixes the carbon-encapsulated copper nanoparticles and high-temperature silicone rubber to ensure that the carbon-encapsulated copper nanoparticles are evenly scattered in the silicone rubber substrate to form an integral thermally conductive network chain, thereby improving the thermal conductivity of the silicone rubber.
Owner:GUANGDONG SUNLITE MATERIAL SCI & TECH

Multi-particle ceramic/metal compound heat dissipation substrate and preparation method thereof

The invention discloses a multi-particle ceramic/metal compound heat dissipation substrate and a preparation method thereof. The heat dissipation substrate comprises a ceramic/metal compound material formed by compounding a plurality of ceramics with metal, an insulation layer and a circuit layer, wherein each ceramic and metal compound part is a particle in the ceramic/metal compound material; the total area of particles accounts for 10%-80% that of the ceramic/metal compound material. The heat dissipation substrate has the characteristics of high heat conduction rate, small heat expansion coefficient, low cost, convenience in use and the like, and is applied to the aspects of lamp decorations, communication electronic equipment, power modules, computers, automotive electronics and the like; the stress level of the connection layer of a chip or device substrate and the heat dissipation substrate can be greatly reduced, that the heat dissipation substrate is in close contact with heat sinks of lamps, machine cases and the like can be kept, a heat transfer passage is kept unblocked for a long term, the weight of the metal heat sinks can be reduced, and a heat transfer technology guarantee is provided for greatly prolonging the service lives of components and economically utilizing heat sink materials.
Owner:襄阳新瑞源科技信息有限公司 +1

Corundum-zirconia corundum-titanic acid aluminum no-firing no-soaking sliding brick and preparation method thereof

The invention discloses a corundum-zirconia corundum-titanic acid aluminum no-firing no-soaking sliding brick and a preparation method thereof. The sliding brick is composed of, by weight, 40-55 parts of tabular corundum, 15-25 parts of zirconia corundum, 10-15 parts of titanic acid aluminum, 6-10 parts of spherical calcined alumina, 5-8 parts of metal aluminum powder, 1-2 parts of high-temperature asphalt powder, 1-2 parts of silicon ash, 1-2 parts of antioxidants and 3-5 parts of phenolic resin. According to the corundum-zirconia corundum-titanic acid aluminum no-firing no-soaking sliding brick and the preparation method thereof, the raw materials of the tabular corundum, the zirconia corundum and the titanic acid aluminum are added into the formula, the coefficient of thermal expansion of the material of the sliding brick can be obviously decreased, and the thermal shock stability, the erosion resistance and the slag resistance of the sliding brick are improved; selection and adding amount of the high-temperature asphalt powder, spherical calcined alumina powder and the silicon ash are controlled, and the reasonable strength of the sliding brick in the low-temperature, medium-temperature and high-temperature stages can be achieved; the thermal expansion difference caused by the thermal stress of the temperature difference between inside and outside of the hole diameter of cast steel when the product is used is improved, the crack number is decreased; and the high-temperature comprehensive performance of the sliding brick is remarkably improved, and the service life of the sliding brick is prolonged.
Owner:UNIV OF SCI & TECH LIAONING

Magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material and preparation method thereof

The invention belongs to the field of electronic ceramic materials, and particularly provides a magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material and a preparation method thereof which are used for overcoming the problems of high sintering temperature, large thermal expansion coefficient, low bending strength, high dielectric constant, high dielectric loss and the like of an existing ceramic material. The magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material and the preparation method thereof have the advantagesthat the prepared low-thermal-expansion-coefficient microcrystalline glass has low thermal expansion coefficient (1.0-2.0*10<-6> per DEG C), high bending strength (150-200 MPa), low dielectric constant (5.0-5.5 @1 MHz), low dielectric loss (1.5-3.5*10<-3> @1 MHz) and reliable insulation, thereby satisfying the requirements of an LTCC electronic package substrate material; the magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material can achieve low-temperature sintering at 900-950 DEG C, the process is simple, the stability is high, the production cost is low, and the magnesium-aluminum-silicon low-thermal-expansion-coefficient microcrystalline glass material is suitable for industrial mass production.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

Composite middle layer for performing diffusion bonding on silicon carbide ceramics and bonding process thereof

The invention discloses a composite middle layer for performing diffusion bonding on silicon carbide ceramics and a bonding process thereof. The composite middle layer for performing diffusion bondingon the silicon carbide ceramics is prepared from the following components in percentage by weight: 55 to 65 percent of high-purity titanium hydride powder, 20 to 25 percent of high-purity silicon powder (Si), 12 to 17 percent of high-purity graphite powder (C), and 1 to 3 percent of high-purity aluminum powder (Al). According to the composite middle layer disclosed by the invention, by utilizinga spark plasma sintering technology (SPS), a silicon carbide (SiC) joint, of which the thickness of a bonding layer is 20 micrometers to 100 micrometers, is prepared under a vacuum condition. A bonding layer material mainly consists of a titanium silicon carbide (Ti3SiC2), the silicon carbide (SiC) and titanium carbide (TiC). Through changing the proportions of the raw materials and process parameters of sintering, the highest shearing strength at a room temperature reaches 135.8MPa, and the hardness of the composite material of the bonding layer can reach 28.1GPa, exceeding the hardness of SiC base materials; and therefore, the composite middle layer disclosed by the invention has a higher practical value.
Owner:HEFEI UNIV OF TECH
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