48results about How to "Adjust the coefficient of thermal expansion" patented technology

The invention discloses a complete set of a titanium ceramic powder for a dental department and a preparation method thereof. The titanium ceramic powder comprises bonded ceramic powder, color-maskingceramic powder and body ceramic powder. The bonded ceramic powder comprises the following components in percentage by weight: 50-55 percent of SiO2, 5-10 percent of Al2O3, 8-15 percent of B2O3, 10-15percent of SnO2, 0-1 percent of CaO, 1-3 percent of ZrO2, 4-10 percent of Na2O, 5-8 percent of K2O, 0-1 percent of Li2O, 1-4 percent of BaO and 0-1 percent of F; the color-masking ceramic powder comprises 50-60 percent of SiO2, 3-10 percent of Al2O3, 0.5-1 percent of CaO, 20-30 percent of SnO2, 0-1 percent of TiO2, 0.5-1 percent of ZrO2, 7-10 percent of Na2O, 5-8 percent of K2O and 0.5-4 percentof BaO; and the body ceramic powder comprises 60-70 percent of SiO2, 4-10 percent of Al2O3, 0.5-1 percent of CaO, 1-5 percent of B2O3, 5-10 percent of Na2O, 5-10 percent of K2O, 0.5-1 percent of Li2Oand 5-8 percent of BaO. In the titanium ceramic powder, besides the body ceramic powder, a crystal phase is added in the bonded ceramic powder and the color-masking ceramic powder by an intermediate material technology for secondary synthesis process, thereby not only regulating the thermal expansion coefficient of ceramic materials, but also being beneficial to reducing the ceramic temperature and being simultaneously beneficial to improving the bonding strength of titanium and ceramic.

A copper line-clad aluminum silicon carbide ceramic substrate applicable to radiation of a high-power LED is characterized by consisting of an aluminum silicon carbide layer (1), a copper and aluminum oxide layer (2) and copper lines (3), wherein the copper and aluminum oxide layer (2) is arranged on the alumina layer (1); the copper lines (3) are arranged on the copper and aluminum oxide layer (2); the distance between the copper lines (2) is 0.1-1mm; the widths of the copper lines (2) are 200-1000 microns; the heights of the copper lines (2) are 0.01-2mm; the copper line-clad aluminum silicon carbide ceramic substrate is manufactured by the following steps: weighing SiO2, coke and a fluxing agent, and preparing the raw materials into porous silicon carbide; heating an aluminum block and melting the aluminum block into liquid aluminum, mixing the liquid aluminum with the porous silicon carbide in a certain ratio, and preparing the mixture into aluminum silicon carbide powder and a high-thermal conductivity aluminum silicon carbide substrate; cladding copper on the aluminum silicon carbide substrate, heating at a high temperature to form an eutectic melt, and forming an aluminum silicon carbide ceramic substrate layer, the copper and aluminum oxide layer and a copper layer from the bottom up; and etching conductive copper lines. The ceramic substrate has a good application prospect in the aspect of the radiation of the high-power LED.

The present invention discloses a bismuthate low-melting point and lead-free sealing grass and a preparation method thereof. The bismuthate low-melting point and lead-free sealing grass powder comprises, by mass, 75-90% of base glass and 10-25% of a filler, wherein the filler is a zirconium phosphate salt with an expansion coefficient of -5*10<-6>k<-1>-5*10<-6>k<-1>. The bismuthate low-melting point and lead-free sealing grass of the present invention has characteristics of lead-free property and green environmental protection, can replace the lead-containing glass so as to eliminate the pollution due to the lead, and has excellent chemical stability. The production process is simple and the cost is low. Compared to other filler-doped sealing glass powders, the sealing temperature of the present invention is low, the glass transition temperature of the present invention is 330-370 DEG C, the softening temperature of the present invention is 370-410 DEG C, the sealing temperature of the present invention is less than 450 DEG C. With adjusting the proportion of the filler, the adjustable expansion coefficient can be realized at the low sealing temperature, wherein the adjustment range is (70-90)*10<-7>/DEG C, such that different requirements of the sealing device to the expansion coefficient of the sealing material can be met, and the sealing for VFD, PDP, CRT and other glass products can be directly performed.

The invention relates to a composite high-temperature molybdenum disilicide-base material and a preparation method thereof. The method can prepare the composite high-temperature material under lower production cost, which has the highest room temperature toughness equivalent to that of high-temperature alloys, higher high temperature intensity, high temperature creep resistant performance and certain plastic processing performance; the substrate of the composite high-temperature material is a composite substrate composed of MoSi2 and Si3N4, wherein the average crystal grain size of the MoSi2 is smaller than 2 microns, and the average grain diameter of the Si3N4 particulates is smaller than 1 microns. The method adopts the following technical proposal: Mo2N powder or powder of Mo5Si3 or Mo3Si are used as initial powder to obtain composite powder Mo3Si-Mo5Si3-Si3N4 or Mo5Si3-MoSi2-Si3N4 after being processed by siliconization or nitridation-siliconization, the composite powder is further enhanced and mixed with materials such as Si powder, SiC powder and the like, and is pressing molded, and then a blank is sintered under the temperature of 1415 to 1550 DEG C, and finally the sintered blank is plastic deformed, thus obtaining a required dense article of the composite high-temperature material.

The invention discloses a boride modified glass ceramic based composite high-temperature oxidation resisting coating. The composite high-temperature oxidation resisting coating fired on the surface of a refractory metal matrix is prepared from boride and silicate glass, wherein the boride is at least one or two of HfB2, ZrB2 and TiB2; besides, the invention further discloses a preparation method of the coating. The method comprises steps as follows: 1, the surface of the refractory metal matrix is treated; 2, boride particle modified glass ceramic composite slurry is prepared; 3, a preset layer is obtained by presetting the slurry on the surface of the refractory metal matrix, and the boride modified glass ceramic based composite high-temperature oxidation resisting coating is obtained vacuum high-temperature firing. The composite high-temperature oxidation resisting coating is used for high-temperature protection of the refractory metal matrix and can continuously protect the refractory metal matrix at the protection temperature of 400-1,600 DEG C for 5 h or longer.

The invention discloses a preparation method of a high temperature-resistant and high-insulation sealing glass. The preparation method has the advantages that silicon dioxide is used as a skeleton structure; by adding BaO (barium oxide) as a generating body of glass, the melting temperature of the glass is lowered, the heat expansion coefficient of the glass is adjusted, and the fluidity of the glass is improved; by adding Al2O3 (aluminum oxide), an AlPO4 (aluminium phosphate) unit can be formed in the glass, and a straight chain is changed into a network structure, so that the structure of the glass is stable, and the chemical stability is improved; by adding ZrO2 (zirconium dioxide), the chemical stability of the glass is favorably improved; by replacing one part of BaO by other divalent metal oxides, such as CaO (calcium oxide), the melting temperature of the glass is lowered, the expansion coefficient of the glass is adjusted, and the chemical stability of the glass is improved; by adding TiO2 (titanium dioxide), the glass has high and low dielectric constants, and the electric insulation property of the glass is improved; by adding As2O5 (diarsenic pentoxide) into the formation of the glass structure, the separating from the network skeleton of the glass is avoided; the sealing temperature of the sealing glass is 1000 to 1050 DEG C, and the heat expansion coefficient is 70 to 100*10<-7>/DEG C; after sealing, the high temperature and high pressure resistant properties are good, and the insulation property is excellent.

The invention discloses lithium-sodium-potassium codoped dental microcrystalline glass and a preparation method and application thereof. The glass is prepared from, by mass, 65%-75% of SiO2, 5%-10% of Li2O, 5%-10% of Na2O, 5%-10% of K2O, 4%-6% of P2O5 and 4%-6% of ZrO2. The sum of the mass fractions of the components is 100%. A glass block is firstly obtained through a fusion pouring method, a glass intermediate R2SiO3 (R=Li, Na and K) easy to machine is obtained after devitrification treatment is carried out, then secondary thermal treatment is carried out, and the finished microcrystalline glass with R2Si2O5 (R=Li, Na and K) as a main crystalline phase is obtained. The microcrystalline glass has excellent bending strength and other mechanical properties and can be used for dental all-ceramic repair materials.

The invention discloses a preparation method and a sealing process of an explosion-proof primary lithium battery cover group and sealing glass. A glass material which is resistant to electrolyte corrosion, excellent in electrochemical performance, controllable in mechanical strength and used for sealing the primary lithium battery cover group is provided, and the compressive strength of the glass is controlled by designing glass components and the sealing thickness. The explosion-proof principle is that when the internal pressure of the battery is greater than the designed pressure in the use process, namely the pressure of the battery is overloaded, the pressure-bearing strength of the glass material is just reached, so that the glass is cracked, the internal pressure of the battery is slowly released, and the battery does not have dangerous situations such as violent explosion. The shell is made of stainless steel series and carbon steel series, the stainless steel series comprises 304L, 316L and the like, and the core column is made of series iron-nickel alloys such as alloys 4J28, 4J50, 4J52 and the like. A SiO2-B2O3-BaO-Na2O3 glass system is selected as a main body, and various metal oxides are added to adjust the thermal expansion coefficient, the glass softening temperature, the chemical stability and the mechanical properties of the glass.

The invention discloses a titanium alloy protective coating which is characterized in that the coating is an amorphous silica-glass composite coating formed by diffusing and distributing 20-40 weight percent of amorphous silica particles in a glass matrix, wherein the glass matrix in the composite coating comprises the following raw materials in parts by mass: 30-40 parts of silica, 20-30 parts of boron oxide, 2-5 parts of aluminum oxide, 5-15 parts of magnesium oxide, 5-15 parts of calcium oxide and 10-20 parts of sodium oxide. The method for preparing the titanium alloy protective coating comprises the following steps: preparing glass powder; preparing slurry for the composite coating, pretreating the surface of the titanium alloy, coating the slurry and sintering the composite coating. The composite coating prepared in the invention can be sintered at a low temperature and has excellent high-temperature oxidization resistance. Meanwhile, the composite coating is low in raw material cost, simple and feasible in preparation process and suitable for industrial production.

The invention belongs to the technical field of ceramic glaze preparation, and particularly relates to a composition for preparing matte white glaze, and a firing method of the matte white glaze. According to the matte white glaze provided by the invention, slag powder, calcined kaolin and talc are matched for use, so that the problem that bubbles are generated on the glaze due to the fact that alarge amount of gas is released in the slag powder firing process can be avoided, the texture of the glaze is improved, the roughness of the glaze is improved, the thermal expansion coefficient of theglaze is adjusted, and the problem that the glaze cracks due to the fact that a large amount of slag powder is added into the glaze is reduced; the slag powder has high fluidity under a high-temperature firing condition, and the calcined kaolin and the talc are matched for use, so that bubbles generated on the glaze surface can be inhibited while the problem of high fluidity of the slag powder ata high temperature is controlled, the glaze surface is smooth, and the glaze surface texture is improved; and a large amount of slag powder can be utilized to realize recycling of the slag powder, and environmental pollution and resource waste can be effectively reduced.

The invention belongs to the field of sealing glass and preparation thereof, and particularly relates to a preparation method and a packaging process of a sealing glass material for a lithium- manganese dioxide battery cover group. The preparation method of the sealing glass material for the lithium-manganese dioxide battery cover group comprises the following steps: 1) selecting the following raw materials in molar percentage: 40-60% of SiO2, 5-25% of B2O3, 0-5% of Al2O3, 5-15% of BaO, 5-15% of Na2O, 0-5% of K2O, 0-5% of MgO, 0-5% of CaO, 0-5% of TiO2, 0-5% of ZrO2, 0-5% of ZnO and 0-5% of Cr2O3, wherein various oxides should comprise various salts and acid-base compounds thereof. According to the preparation method of the sealing glass material for the lithium-manganese dioxide battery cover group and the sealing process of the sealing glass material, the corrosion resistance of the lithium-manganese dioxide battery cover group glass is improved, the air tightness of a sealing piece is guaranteed, the chemical stability and high-temperature and high-pressure insulativity of the sealing piece are improved, and the preparation process is simple, and suitable for industrial production.

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.

A polyamic acid composition is formed by polymerizing a dianhydride monomer and a diamine monomer, and the molar ratio of the dianhydride monomer to the diamine monomer ranges from 0.9 to 1.1. the diamine monomer comprises a diamine monomer containing a liquid crystal unit, a diamine monomer containing a soft structure and a diamine monomer containing a nitrogen heterocyclic ring; in the diamine monomer, the molar percentage of the diamine monomer containing the nitrogen heterocyclic ring is 3%-8%, and the sum of the molar percentage of the diamine monomer containing the liquid crystal unit and the molar percentage of the diamine monomer containing the soft structure is 92%-97%. The invention also provides a polyimide copper-clad plate prepared by cyclizing the polyamide acid composition and a circuit board prepared by applying the polyimide copper-clad plate.

The invention discloses a lightweight aluminum alloy composite material which comprises 0.5-2% of a lubricating phase, 0.5-15% of a ceramic phase and the balance of a matrix alloy, wherein the matrix comprises the following elements in percentage by mass: 20-30% of silicon, 2-4% of copper, 2-4% of magnesium, 0.1-0.5% of zirconium, 0.1-2% of iron, 0.1-2% of nickel and the balance of aluminum; the lubricating phase is molybdenum disulfide, and the ceramic phase is one or a combination of two of zirconium oxide and silicon carbide powder. The invention further discloses a compressor roller prepared from the lightweight aluminum alloy composite material and a preparation method of the compressor roller. The lightweight aluminum alloy composite material provided by the invention has good wear-resistant and high-strength properties, is light in weight, is used for manufacturing parts, such as rollers, and is small in specific gravity and low in noise, the wear-resistant and corrosion-resistant properties are improved, and the maintenance caused by wear is greatly reduced.

The invention relates to frit composition, frit paste composition comprising the frit composition, a sealing method adopting the glass frit paste composition and an electric device for sealing with the sealing method. According to the frit composition, a manganese-nitrogen compound which has a specific molecular formula and adopts an anti-perovskite crystal structure is taken as filler and has a negative thermal expansion characteristic in a certain temperature range, the overall thermal expansion coefficient of the frit composition can be well adjusted, accordingly, the overall thermal expansion coefficient of the cured glass frit can approach that of a glass substrate, and the frit composition can be better matched with the glass substrate.

The invention discloses a palladium/ceramic composite film. The composite film is loaded on a porous carrier. The composite film is formed by combining metal palladium or a palladium alloy and ceramics, wherein the volume of the palladium or the palladium alloy accounts for 30%-99%. The composite film is prepared through a physical vapor deposition method. A magnetron sputtering method is preferably adopted for preparing, and the composite film is obtained through sputtering of a palladium or palladium alloy target and a ceramic target at the same time. Through combining of a palladium film and the ceramics, on one hand, ceramic particles are dispersed and distributed in the continuous palladium or palladium alloy, the function of pinning is achieved for the palladium grain boundary, and palladium grain high-temperature grain growth and roughening difficulty is increased; and on the other hand, through introduction of the ceramics, the function of adjusting the palladium film heat expansion coefficient can be achieved, palladium film and ceramics or glass heat expansion mismatching is reduced, and the high-temperature structure stability of the palladium film is improved.

A pipe inner wall plasma in-situ reaction composite processing technology is characterized in that: the processing technology comprises the following steps: (1) preparing thermal reaction powder; (2) preparing the workpieces for processing; (3) starting the workbench, opening the gas and cooling water switch of the plasma equipment, opening the power supply and starting arc by high frequency, adjusting the technological parameter range of the plasma beam, adjusting the rotation speed of the workpiece, and adjusting the feeding speed of the plasma generator; (4) closing the plasma power supply and the switches of the air bottle and powder feeder, and closing the cooling water switch; (5) arranging the processed workpieces in order for use later. The tapered composite coating with high strength can be obtained by the technology.

The invention discloses a preparation method of carbon nanotube composite metal paste. The preparation method comprises the following steps: S1, preparing a carbon nanotube subjected to first metal surface modification; S2, mixing the first metal surface modified carbon nano tube with metal powder and an organic carrier to form carbon nano metal paste; wherein the mass mixing ratio of the carbon nano tube to the metal powder ranges from 1: 59 to 1: 19, and the mass mixing ratio of the first metal surface modified carbon nano tube and the metal powder to the organic carrier ranges from 1: 3 to1: 5.7. According to the invention, the technical problems of low thermal conductivity, low electric conductivity and poor shear strength after the existing nano copper paste is sintered are solved, and the electric conductivity, the thermal conductivity, the shear strength and the connection strength of a sintered layer are improved.

The invention discloses a machine tool bed cast from waste ceramics. The machine tool bed has the advantages of being high in stability, low in thermal expansion coefficient, good in pressure and tension resistance, and the like, and in addition, as waste ceramics are adopted as a raw material, the problem that waste ceramics are randomly disbanded, hard to recycle, and the like, is solved, and the purpose of turning wastes into wealth is achieved. The machine tool bed cast from waste ceramics is mainly prepared from the following raw materials in parts by weight: 70-75 parts of waste ceramicpieces or waste ceramic granules, 8-15 parts of waste ceramic powder, 7-10 parts of an epoxy resin, 1.75-2.5 parts of a curing agent, 1 part of a carbon fiber, 1 part of a basalt fiber, 0-1 part of bismuth, Bi, 0-1 part of antimony, 8-10 parts of silicon powder and 0-10 parts of alumina powder.