79results about How to "Good thermal expansion performance" patented technology

The present invention relates to relates to welding method, and is especially ultrasonic brazing process of obtain composite brazed seam in aluminum-base composite material. The process includes the following steps: 1. filling brazing alloy; 2. primary brazing; and 3. ultrasonic vibration treatment to obtain composite brazed seam in aluminum-base composite material. The said brazing process can obtain brazed joint with greatly improved mechanical performance and heat expansion performance, low heat expansion coefficient, and high strength near that of the mother material.

The invention discloses a resin composition which comprises the following solids by weight: (a) 100 parts of a bismaleimide resin prepolymer, (b) 5-80 parts of cyanate ester, (c) 0-50 parts of a flame retardant and (d) 0-65 parts of inorganic filler, wherein the bismaleimide resin prepolymer is obtained by carrying out reaction on an allyl compound and bismaleimide resin and the ratio of bismaleimide resin and allyl compound by weight is 100: (10-120). According to the resin composition disclosed by the invention, by adopting siloxane containing allyl at the tail end as a modifier of bismaleimide resin and limiting the content of siloxane in the modifier, unreacted siloxane resin is not generated in reaction, so that the advantages and characteristics of siloxane resin can be fully exerted and the interlaminar adhesive force at the high temperature is greatly improved. Moreover, the thermal expansion properties of the solids are optimized, so that the resin composition satisfies the requirements on high precision electronic substrate materials.

A braze alloy composition for sealing a ceramic component to a metal component in an electrochemical cell is presented. The braze alloy composition includes nickel, germanium, and an active metal element. The braze alloy includes germanium in an amount greater than about 5 weight percent, and the active metal element in an amount less than about 10 weight percent. A method for sealing a ceramic component to a metal component in an electrochemical cell and, an electrochemical cell sealed thereby, are also provided.

The invention discloses a cylinder body of an actuating cylinder, which comprises an inner lining (1) and a first fiber composite material layer (2) bonded outside the inner lining, wherein the first fiber composite material layer is laminated by a first fiber material and a resin matrix. The invention also discloses concrete pumping equipment comprising the cylinder body. Accordingly, the invention further discloses a manufacturing method of the cylinder body of the actuating cylinder, which comprises an inner lining forming step of forming the inner lining, and a bonding step of forming the first fiber composite material layer with the first fiber material and the resin matrix and bonding the first fiber composite material layer to the outer part of the inner lining. According to the technical scheme, the cylinder body of the actuating cylinder has higher strength and lighter weight, is better in fatigue resistance and corrosion resistance, and has low thermal expansibility. Besides, since the inner lining of the cylinder body can meet the requirements for tightness of the cylinder body inner wall and the wear resistance upon contact with a piston, the inner lining does not affect the service performance of the cylinder body.

A braze alloy composition for sealing a ceramic component to a metal component in an electrochemical cell is presented. The braze alloy composition includes nickel, silicon, boron, and an active metal element. The braze alloy includes nickel in an amount greater than about 50 weight percent, and the active metal element in an amount less than about 10 weight percent. An electrochemical cell using the braze alloy for sealing a ceramic component to a metal component in the cell is also provided.

The invention provides cerium-calcium bi-element co-doped lanthanum zirconate nano ceramic powder and a preparation method thereof. The preparation method includes following steps: preparing a mixed solution, and mixing the same with a precipitant to obtain hydroxide colloid; separating and washing the hydroxide colloid to obtain precipitate; press-filtering the precipitate to obtain semi-solid-state hydroxide gel; well mixing the semi-solid-state hydroxide gel with a dispersant to obtain a mixture; distilling the mixture, and drying to obtain solid powder; calcining the solid powder to obtain the cerium-calcium bi-element co-doped lanthanum zirconate nano ceramic powder. The structural formula of the cerium-calcium bi-element co-doped lanthanum zirconate nano ceramic powder is (La1-2xCexCax)2(Zr0.7Ce0.3)2O7, wherein x is greater than or equal to 0.05 and smaller than or equal to 0.2. The preparation method is few in process and easy to control.

The invention discloses a calendering system, which comprises a support, at least two feeding devices, at least one pressing device, a receiving device and a temperature regulating device. Wherein, at least two feeding devices are used to continuously output the substrate and the first film respectively; at least one pressing device is arranged on the support, and is used to press the first film from the feeding device on the substrate; the receiving device It is used to continuously collect the second film formed after pressing by the pressing device; the temperature regulating device is arranged between the feeding device and the pressing device, and is used to adjust the temperature of the first film from the feeding device. In the calendering system of this structure, a temperature adjustment device is installed between the feeding device and the closing device to adjust the physical properties of the first film before the pressing process, so that the thermal expansion, ductility, and flexibility of the first film are improved. The calendering quality of the film, the structure of the whole calendering system is simple and easy to operate.

The invention provides a metal laminated plate and a preparation thereof. The metal laminated plate consists of a polyimide resin layer and a metal layer, wherein the thermal expansion coefficient ofthe polyimide resin layer is 18 to 30 ppm/DEG C, and the hygroscopic expansion coefficient of the polyimide resin layer is 2 to 16 ppm; and the peeling strength between the polyimide resin layer and the metal layer is 10 to 20 N/mm. The method for preparing the metal laminated plate comprises the following steps: firstly, dissolving aromatic tetracarboxylic dianhydride and aromatic diamine in an polar aprotic solvent for reaction to form solution of polyamic acid, wherein the aromatic diamine may be benzidine, para-phenylene diamine, or 4,4'-diamino diphenyl ether; and secondly, coating the polyamic acid solution on the metal layer, and performing imidization to obtain the metal laminated layer. The metal laminated layer prepared by the method has the characteristics of high binding forcebetween the polyimide resin layer and the metal layer, high dimensional stability of the polyimide resin layer and small hygroscopic expansion coefficient.

The present invention relates to an alkoxysilylated epoxy compound, a composite exhibiting good heat resistance properties, low CTE and high glass transition temperature and not requiring a coupling agent, a composition including the same, a cured product formed of the composition, a use of the cured product, and a method of preparing the epoxy compound having alkoxysilyl group. An epoxy compound having an epoxy group and an alkoxysilyl group, a composition including the epoxy compound, a curing agent, a filler and/or a reaction catalyst, a cured product of the composition, and a use of the composition including an electronic part are provided. In a composite and/or cured product, the epoxy composition exhibits improved heat resistance properties, decreased CTE, and increased glass transition temperature or Tg-less. The cured product exhibits good flame retardant properties by the introduction of the alkoxysilyl group.

The present invention provides a multilayer laminated plate with spherical fillers and a circuit board thereof. The multilayer laminated plate is formed by alternate stacking and laminating of a plurality of conducting layers and insulating layers, one conducting layer and another adjacent conducting layer in the multilayer laminated plate are brought into conduction by a conductive pole in a buried hole structure in order to improve circuit designability, wherein the insulating layers of the multilayer laminated plate are provided with spherical fillers inside in order to increase heat conductivity of the insulating layers and modulate heat expansibility of the insulating layers. The insulating layers are formed by solidification of semi-solid films via a hot pressboard laminating program, during the hot pressboard laminating program with the proviso of high temperature and high pressure, the semi-solid films melt into resin solution and fill in the buried hole structure, then the resin solution further solidifies to form the insulating layers. The spherical fillers are uniformly distributed in the buried hole structure of the multilayer laminated plate, which can improve the overall heat conductivity and modulate the heat expansibility of the multilayer laminated plate. In addition, the multilayer laminated plate can effectively give off heat when used in circuit board downstream high temperature assembling technology, at the same time, heat resistance as well as process yield rate of the plate can be improved.

The invention discloses a manufacturing method of a cylinder of an actuating cylinder, which comprises a liner layer forming step to form the liner layer (1); and a combining step: a first fiber material preimpregnated with semisolid matrix resin is winded out of the liner layer (1) by a dry winding process so that a first fiber composite material layer (2) formed by the first fiber material and the matrix resin is combined out of the liner layer (1). The cylinder of the actuating cylinder manufactured by the manufacturing method comprises the liner layer and the first fiber composite material layer so that the cylinder is larger in strength, lighter in weight, fatigue resistant and good in anti-corrosion performance as well as smaller in thermal expansion. Furthermore, as the liner layer of the cylinder can meet the requirements of tightness of the inner wall of the cylinder and wear-resistance of the inner wall contacted with a piston, the usability of the cylinder is not affected. In addition, weight of the cylinder can be accurately controlled by using the first fiber composite material layer by the dry winding process, so that the production efficiency is higher.

The invention discloses a manufacturing process of a car lamp reflector. The manufacturing process is characterized in that a bulk molding compound (BMC) is adopted as a material, and the reflector is manufactured in an injection molding machine through the BMC. The manufacturing process comprises the specific steps of 1, mold closing, wherein an upper mold block fast approaches a lower mold block, and after it is determined that no foreign matter exists, a system is converted into high pressure, and a mold plate is closed; 2, in-place forward movement of an injection table; 3, injection molding, wherein a screw is set at the three-section speed, pressure and stroke, and a melting material at the front end of a barrel is injected into a mold cavity; 4, heating and pressure maintaining, wherein the mold cavity is heated, meanwhile, the pressure of the barrel is kept, and finally the mold cavity is cooled and formed; 5, heating and glue melting; 6, retreating of the injection table, wherein the injection table retreats to the designated spot after glue melting is finished; and 7, ejection, wherein a product is ejected out by an ejector pin. The indexes of characteristics of the BMC and the forming condition in the injection molding machine are strictly controlled, so that the injection molding product is stable in stability, high in surface flatness and size precision and good in stability, and an excellent multi-curved-surface special-shaped reflector material is achieved.

The invention discloses a preparation method of an enhanced UO2 nuclear fuel pellet to solve the problems of rapid degrease of the thermal conductivity at a high temperature and rapid weakening of thegaseous fission product retention capacity of UO2 fuel pellets in the prior art. The preparation method comprises the following steps: cold-pressing shaping of UO2-reinforcing phase compound particles having good sphericility to obtain a nuclear fuel pellet blank, and sintering of the nuclear fuel pellet then in an active atmosphere at a high temperature to obtain the enhanced UO2 nuclear fuel pellet. The UO2-reinforcing phase compound particles are prepared from UO2 powder, a reinforcing phase and a lubricant; and the use amount of the reinforcing phase is 0.05-5% of the weight of the UO2 powder. The method is simple, and is scientifically designed; and the thermal conductivity at a high temperature and the gaseous fission product retention capacity of the enhanced UO2 fuel pellet are greatly higher than those of the existing UO2 fuel pellets.

A braze alloy composition for sealing a ceramic component to a metal component in an electrochemical cell is presented. The braze alloy composition includes copper, nickel, and an active metal element. The braze alloy includes nickel in an amount less than about 30 weight percent, and the active metal element in an amount less than about 10 weight percent. An electrochemical cell using the braze alloy for sealing a ceramic component to a metal component in the cell is also provided.

The invention discloses a preparation method of a calcium hexaluminate foamed ceramic with a multilayer structure. The preparation method comprises the following steps: completely immersing a pretreated polyurethane sponge template in slurry I, extruding redundant slurry by rolling, then carrying out high-pressure blast or centrifugal slurry throwing, and drying at 100-120 DEG C for 16-24 hours; then putting the mixture into a muffle furnace at 700-900 DEG C, keeping the temperature for 2-4 hours, and naturally cooling; and completely immersing a calcium hexaluminate foamed ceramic preform in the slurry II, keeping for 3-7 minutes under a vacuum condition, carrying out high-pressure air blowing or centrifugal slurry throwing and natural drying to obtain a calcium hexaluminate foamed ceramic green body, drying for 16-24 hours at 100-120 DEG C, then putting the green body into a high-temperature furnace, carrying out heat preservation for 2-5 hours at 1500-1600 DEG C, and then cooling along with the furnace to obtain the calcium hexaluminate foamed ceramic with the multilayer structure. Through detection, the normal-temperature compressive strength of the prepared microporous multilayer structure calcium hexaluminate foamed ceramic is 3.0-8.0 MPa, the number of times of water cooling circulation is 12-20; and the anti-erosion and anti-scouring capability is excellent.

Heat-expandable microspheres with high encapsulation efficiency of a blowing agent and good heat-expansion performance, a process for reproducibly producing the heat-expandable microspheres and application thereof are provided. The heat-expandable microspheres comprise essentially a thermoplastic resin shell and a blowing agent encapsulated therein, and contain not more than 500 ppm of silicon, not more than 350 ppm of aluminum and not more than 600 ppm of the total of the silicon and aluminum. The heat-expandable microspheres retain at least 70% of the blowing agent encapsulated therein at the temperature which is the average of their expansion-initiation temperature and maximum expansion temperature.

The invention discloses a temperature-sensing wax mixture for a temperature-sensing component, comprising paraffin wax and heat-conducting carbon fibres having a heat conductivity coefficient of greater than 450 w/m.k. A preparation method for the temperature-sensing wax mixture comprises the following steps of: proportioning the paraffin wax and the heat-conducting carbon fibres in a certain proportioning ratio by weight, uniformly mixing, and then grinding for 50-120 hours by adopting a high-energy ball mill under the protection of an inert gas, thus coating a layer of paraffin wax protecting film around the heat-conducting carbon fibres, and then obtaining the temperature-sensing wax mixture. According to the temperature-sensing wax mixture, the heat-conducting carbon fibres are used for replacing copper powder, so that the cost is low, and the thermal expansion is good, and the selected heat-conducting carbon fibres have a heat conductivity coefficient of greater than 450 w/m.k, so that a response speed for temperature sense is greatly increased, and adaptability to application occasions with a high sensitivity requirement on the temperature-sensing component can be met; simultaneously, the heat-conducting carbon fibres and the paraffin wax are mixed and then ground by adopting the high-energy ball mill, thus coating a layer of paraffin wax protecting film around the heat-conducting carbon fibres, so that the heat sensitivity of the whole temperature-sensing wax mixture can be improved, and the process is simple and beneficial to industrialized production.

The invention relates to a preparation method of a thermoplastic polyimide/modified silicon dioxide composite film which can be used for a flexible high-frequency copper clad laminate. The specific steps comprise preparing a nano-silica microsphere emulsion, preparing thermoplastic polyimide, using a silane coupling agent as a surfactant to combine polyimide and silicon dioxide, wherein the surface of nano-SiO2 is coated with the thermoplastic polyimide molecular layer, and the water absorbency of the composite is improved by adding SiO2, SiO2 is uniformly dispersed in the composite film, SiO2is used as a particle to restrict the expansion of the composite film in the thermal expansion process of the composite film, and the thermal expansion performance of the polyimide is effectively improved. After the preparation of silicon dioxide, silicon dioxide directly participates in the composite reaction with a polyimide precursor without drying, thereby avoiding the agglomeration of microspheres in the drying process during industrial production of nano-silicon dioxide, and enhancing the bending resistance of the prepared copper clad laminate.

The invention discloses a polytetrafluoroethylene high-frequency copper-clad plate with high thermal conductivity, and relates to the technical field of high-frequency copper-clad plates. The invention discloses the polytetrafluoroethylene high-frequency copper-clad plate with high thermal conductivity, which comprises two copper layers, and characterized by comprising a high-thermal-conductivitypolytetrafluoroethylene substrate positioned between the two copper layers; the high-thermal-conductivity polytetrafluoroethylene substrate is prepared from the following raw materials in parts by weight: 70-80 parts of a PTFE/BN composite material, 0.8-1.5 parts of a titanate coupling agent, 5-10 parts of titanium powder, 5-8 parts of silicon oxide, 5-8 parts of yttrium oxide, 3-5 parts of aluminum oxide and a proper amount of ethanol. The invention further discloses the preparation method of the PTFE/BN composite material and a preparation method of the high-thermal-conductivity polytetrafluoroethylene substrate. The PTFE high-frequency copper-clad plate provided by the invention has the advantages of excellent heat-conducting property, higher dielectric constant, lower dielectric loss,high peel strength, high mechanical strength, low water absorption and low thermal expansion coefficient.

There is provided a composition including an alkoxysilylated epoxy compound, a composition of which exhibits good heat resistance properties, low CTE and high glass transition temperature or Tg-less and not requiring a separate coupling agent, and inorganic particles, a cured product formed of the composition, and a use of the cured product. An epoxy composition including an alkoxysilylated epoxy compound and inorganic particles, an epoxy composition including an epoxy compound, inorganic particles and a curing agent, a cured product of the composition, and a use of the composition are provided. Since chemical bonds may be formed between the alkoxysilyl group and the inorganic particles and between the alkoxysilyl groups, a composition of the composition including the alkoxysilylated epoxy compound and the inorganic particles exhibits improved heat resistance properties, decreased CTE, and increased glass transition temperature or Tg less.