573 results about "Whisker" patented technology

The invention belongs to the field of macromolecule inorganic chemistry, and in particular relates to a method for preparing a graphene toughened silicon carbide ceramic composite material. Specifically, the method comprises the following steps: by taking graphite oxide as a carbon source, wrapping the surface of reduced graphene oxide with a layer of SiO2 granules by using a hydrothermal method so as to form a good interface layer between graphene and SiC, uniformly dispersing, and implementing carbon thermal reduction reaction at the interface of graphene and SiO2 in the high-temperature sintering process so as to growth silicon carbide crystal whisker and granules in situ, thereby improving the interface strength and the oxidation resistance, achieving an interface intensification function, improving crack expansion resistance and further improving the fracture toughness of ceramic. The method aims at the defects that graphene is poor in dispersity and high-temperature oxidation resistance in a conventional graphene/silicon carbide composite material, in-situ growth, crack self-healing and toughness mechanisms are applied to a preparation technique of a graphene/silicon carbide material, and thus graphene toughened silicon carbide ceramic with excellent mechanical properties and interface binding properties can be prepared.

The invention provides a high-tenacity polycrystalline composite material. The high-tenacity polycrystalline composite material particularly comprises, by mass, 72%-92% of polycrystalline super-hard phase, 7.5%-25% of binding agents and 0.5%-15% of toughening agents. The toughening agents are one of aluminum oxide whiskers, silicon nitride whiskers, silicon carbide whiskers, carbon nano tubes and graphene or the combination of several of the aluminum oxide whiskers, the silicon nitride whiskers, the silicon carbide whiskers, the carbon nano tubes and the graphene. The invention further provides a high-tenacity polycrystalline blade prepared from the high-tenacity polycrystalline composite material and a preparation method of the high-tenacity polycrystalline blade. The preparation method comprises the steps of isostatic forming, vacuum heat treatment activation, and high-temperature and high-pressure sintering. The high-tenacity polycrystalline blade has good tenacity and cutting performance, and the preparation technique is simple and easy to implement.

The invention relates to a manufacturing method of an electronic-grade polyimide film with low linear expansion coefficient. The method is characterized by comprising the steps that (1) the step-by-step condensation polymerization technology or the blending compounding technology is used for obtaining two or more polyamide acid glue solutions comprising rigid structures and soft structures at the same time and are different in rigidity and softness; (2) ultrafine inorganic whiskers, like zinc oxide whiskers, silicon carbide whiskers and zirconium tungstate whiskers, which are subjected to surface organic modification already and/or nanoparticle materials are smashed and cavitated through high-energy-density supersonic waves, and then the functional fillers are compounded with polybasic polyamide acid in an in-situ micro-nano mode; (3) the compounded glue solutions are subjected to filtration, vacuum defoamation, extrusion casting filming, chemical amidization or thermal amidization, infrared complete amidization, high-temperature thermal forming processing, corona processing and a reeling process, and therefore the electronic-grade polyimide film with the thickness being 7.5-125 micrometers, the linear expansion coefficient being 5-18ppm/DEG C, and good physical mechanical performance is obtained.

The present invention has an object to provide a tin-plated film and a method for producing the same, capable of preventing whiskers from being generated and simultaneously preventing the surface of a substrate to be plated, which is not covered with a tin-plated film, from discoloring due to oxidation, by which prevention of whisker generation, suppression of whisker growth, and prevention of discoloring of a substrate to be plated are compatible with simplified operations ensuring excellent productivity. The method is provided with the steps of removing a part of a tin-plated film formed on copper or copper alloy; processing to prevent discoloring of the copper or copper alloy from which the tin-plated film is removed; and applying heat energy to the tin-plated film of the copper or copper alloy which is processed to prevent discoloring.

The invention discloses a high-heat-conductivity high-toughness composite material which is prepared from the following ingredients in parts by mass: 100 parts of matrix resin, 1-10 parts of a granular heat conductivity filler, 25-40 parts of a flake heat conductivity filler, 1-10 parts of a crystal whisker heat conductivity filler, 1-10 parts of a toughening agent and 0.1-0.5 part of a coupling agent. The invention further discloses a preparation method of the high-heat conductivity high-toughness composite material. A main body of a three-dimensional heat conductivity network is formed by graphite in the material; the crystal whisker heat conductivity filler penetrates through a resin layer and then is connected with graphite heat conductivity layers which are isolated by the resin; and the granular heat conductivity filler generates more mutual particle contact points. Thus, as the heat conductivity fillers of different shapes are effectively stacked, more heat conductivity paths are formed, and the heat conductivity property of the composite material is effectively improved; and meanwhile the granular heat conductivity filler and the crystal whisker heat conductivity filler have the toughening and enhancing functions on the composite material, so that the composite material has the advantages of high both heat conductivity and toughness.

The invention relates to a formula design for a thermoplastic halogen-free low-smoke flame-retardant cable insulating material and the manufacturing process thereof, concretely, using polyethene copolymer and/or modified ethylene-propylene rubber as a substrate, adding in halogen-free and nontoxic flame-retardant agent (nano magnesium hydroxide or aluminum hydroxide) and inorganic crystal whisker strengthening material as primary components, and adding in proper assistant, proportioning, mixing, plasticizing and making grains to make the insulating material. Its technical characters: not containing halogen, P, Al and other heavy metals; having god mechanical property, machining property and superior flame retardancy and having excellent thermal deforming, thermal ageing and thermal shock properties. The made cables have high safety and reliability. It is applied to the cables operating at 70 deg.C-105 deg.C long time, such as ship cables, cables for nuclear power plants, power and control cables for high-rise buildings, etc.

The invention belongs to the field of the preparation of ceramic matrix composites, and particularly relates to a SiC whisker reinforced SiC ceramic matrix composite and a preparation method thereof. The SiC whisker reinforced SiC ceramic matrix composite is prepared from a preform through a Si or Si alloy infiltration reaction, and the preform is prepared by compressing and molding a raw material comprising a rice hull SiC whiskerized product. By the method, the preparation process is simple, the temperature of the infiltration reaction is low, external pressure is not required, and the preform can be prepared into complicate shapes and can be used for preparing members with complicated shapes. A main composition phase SiC of the composite comes from rice hull, the raw material is rich, the cost is low, the manufacturing cost of the ceramic matrix composite can be remarkably reduced, the resource is saved and the environment is protected. The SiC ceramic matrix composite has good performance, SiC whiskers have the effect of strengthening materials, and the SiC whisker reinforced SiC ceramic matrix composite can be used for applicable occasions of SiC reaction sintering ceramic material products such as sliding bearings, corrosion-resistant and wear-resistant pipelines, valves and fan blades, military and civil body armors and the like.

There is provided a method and composition for applying a wear resistant composite coating onto a metal surface of an electrical component. The method comprises contacting the metal surface with an electrolytic plating composition comprising (a) a source of tin ions and (b) non-metallic particles, and applying an external source of electrons to the electrolytic plating composition to thereby electrolytically deposit the composite coating onto the metal surface, wherein the composite coating comprises tin metal and the non-metallic particles.

The invention discloses a crystal whisker toughened tungsten carbide cobalt-base hard alloy material and the preparing method. It takes powder metallurgy technology, employs tungsten carbide- cobalt as base material, adds titanium carbide crystal whisker and prepares toughened tungsten carbide cobalt-base hard alloy material through a certain process. It is characterized in that: (1) employs powder metallurgy technology and prepares out product with different shapes. (2) the rigidity is high, compression strength and toughness are good, the titanium carbide crystal whisker increases toughness on basis of guranteeing strength of said alloy, and it aslo can be used to replace cobalt and as adhesive phase, to improve material performance. (3) the process is simplea nd cost is low. The hard alloy material can be used in mechanics, metallurgy, mine, first-order instrument and military, and uesd to prepare kinds of blade and drilling button, and new knife tool material.

A method of sintering a ZrB₂—SiC composite body at ambient pressures, including blending a first predetermined amount of ZrB₂ powder with a second predetermined amount of SiC powder, wherein both powders are characterized by the presence of surface oxide impurities. Next the blended powders are mixed to yield a substantially homogeneous powder mixture and a portion of the substantially homogeneous powder mixture is formed into a green body. The body is fired to a first temperature, wherein substantially all surface oxide impurities are reduced and/or volatilized to substantially eliminate oxides from the green body, and the body is heated to a second temperature and sintered to yield a composite body of at least about 99 percent theoretical density and characterized by SiC whisker-like inclusions distributed substantially evenly in a ZrB₂ matrix.

The invention provides a mullite-whisker-reinforced anorthite porous ceramic and a preparation method thereof. The preparation method comprises the following steps: preparing pure-phase high-length-diameter-ratio high-dispersibility mullite whisker by a solid reaction process, preparing a porous ceramic billet from the mullite whisker, alpha-aluminum oxide, silicon dioxide and calcium carbonate powder by a foam gelcasting process, and finally, sintering at 1450 DEG C for 5 hours to obtain the mullite-whisker-reinforced anorthite porous ceramic. The material prepared by the method has the advantages of high porosity, low thermal conductivity and high strength. The apparent porosity of the sample, in which the addition amount of the mullite whisker is 50 wt.%, is up to 90%; the room-temperature vacuum thermal conductivity is only 0.045 W/m.K; and the compression strength is up to 1.1 MPa. The research shows that the added mullite whisker inhibits the growth of the anorthite grains, and the high porosity, complicated pore structure and fine grains are main reasons for low thermal conductivity. The tight combination between the added whisker and base greatly enhances the strength of the material.

The invention discloses a compounded wave-absorbing material of grapheme/four-pin zinc oxide whisker and a preparation method thereof, and belongs to the field of microwave absorption. Natural scale graphite is used as a raw material to prepare reduction-oxidation graphene; the obtained reduction-oxidation graphene is dispersed into an alcohol solution for ultrasound treatment for 3-5 h to obtain reduction-oxidation graphene dispersion liquid with the concentration of 0.3-0.6 mg/ml; adding four-pin zinc oxide whisker into the reduction-oxidation graphene dispersion liquid, wherein the mass fraction of graphene is 4-8% and the mass fraction of four-pin zinc oxide whisker is 8-12%; performing magnetic mixing for 30-40 min wherein the rotating speed is controlled at 400-600 rpm/min and the temperature is controlled within 20-40 DEG C; placing the mixed solution into a drying oven for drying, and keeping the temperature at 60-80 DEG C for 6-8 h, so as to obtain the compounded wave-absorbing material. The preparation process is simple, the prepared wave-absorbing material is excellent in wave-absorbing property, strong in wave-absorbing ability, wide in wave-absorbing frequency band, and strong in regulatory property; high absorption at different frequency can be realized by thickness adjustment.

The invention discloses a ceramic cutting tool and the preparation method thereof special for a smashing line board or a circuit board, and belongs to the art of the smashing equipment. The ceramic cutting tool takes crystal whisker as the plasticizing material; tungsten carbide as the substrate material; titanium carbide as anti-friction agent; carbon as deoxidizing agent; and chromic compound, lanthanum oxide and cerium oxide as additive. The ingredients are evenly blended and directly molded by heat pressing. The raw material is not taken out until being fully mixed, and is then positioned into the sample heat pressing groove of a hot-press machine. The thermo-compression intensity of pressure is 10-40MPa, and the hot-press temperature ranges from 1,480 to 1,600DEG C. The flexible ceramic cutting tool of the invention is provided with good resilience, wearlessness, high rigidity and chemical stability. The technique of the cutting tool is quite simple and the production period is far shorter than the production period of the conventional preparation method that carries the compression molding of the evenly mixed raw materials first and then the sinter molding. The cutting tool material is fit for the cutting tool special for the making of a waste line board and the smashing equipment of the circuit board.

The invention discloses a high-porosity porous ceramic tube formed by interlocking uniform mullite whiskers and a preparing method of the ceramic tube. Three types of powder including an aluminum source, a silicon source and a whisker growth catalyst are evenly mixed and then dispersed in an organic solution which is obtained by dissolving PESF and PVP in an NMP solvent, the liquid is mixed and ball-milled evenly and then placed in a die for extrusion phase conversion forming, and a ceramic tube blank is obtained. The blank is sintered at the temperature of 1300-1500 DEG C, the whiskers grow in situ and form an interlocked structure, and therefore the high-porosity mullite whisker porous ceramic tube with the porosity larger than 70% and the breaking strength larger than about 3 MPa is obtained. The mullite whisker porous ceramic tube can be applied in the fields of thermal insulation and preservation, noise reduction, catalyst carrier and gas-solid separation and the like.

The invention provides a silicon carbide whisker reinforced silicon nitride ceramic composite material and a preparation method thereof. A matrix of the silicon carbide whisker reinforced silicon nitride ceramic composite material is silicon nitride ceramic; a reinforced material is silicon carbide whisker. The preparation method comprises the following steps: mixing the silicon carbide whisker with silicon powder and granulating, and then adding a sintering aid, a monomer crosslinking agent, a dispersing agent and pure water to be mixed to prepare a premix solution; adding an initiator and a catalyst into the premix solution, using aluminium oxide as a ball-milling medium to conduct ball mill for a period of time in a nylon tank, performing filtration and drying, sintering dried powder into a ceramic by adopting hot isostatic pressing, performing shape processing on the ceramic, and conducting nitridation on the ceramic finally. The silicon carbide whisker reinforced silicon nitride ceramic is improved in high-temperature strength, wear resistance, and abrasion resistance, so that silicon nitride ceramic can be more perfectly applied to wider field.

The invention relates to a high-temperature-resistant high-strength tough silicon nitride based wave-transparent composite material and a preparation method thereof. The preparation method comprises the following steps: preparing a porous Si3N4 whisker biscuit through gel casting, and performing drying and rubber discharging to obtain a porous Si3N4 preform; and preparing a boron nitride (BN) interface in the whisker preform through a chemical vapor infiltration (CVI) process, and preparing a multilayer alternate BN/Si3N4 matrix through the CVI process. In accordance with the design requirements for the structure and performance of a high-temperature wave-transparent antenna housing, the microstructure of each layer, the number of layers and the layer thickness of the multilayer alternateBN/Si3N4 matrix are regulated and controlled through CVI regulation and control to realize the regulation, control and optimization of the structure and performance of the composite material, therebyobtaining the high-temperature-resistant high-strength high-toughness Si3N4 based wave-transparent composite material which realizes broadband wave transmission and has excellent thermophysical properties.

The present invention provides a metallic material for electronic components having a low degree of whisker formation and a high durability, and connector terminals, connectors and electronic components using the metallic material. The metallic material for electronic components includes: a base material; on the base material, an lower layer constituted with one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co and Cu; on the lower layer, an upper layer constituted with an alloy composed of one or both of Sn and In (constituent elements A) and one or two or more of Ag, Au, Pt, Pd, Ru, Rh, Os and Ir (constituent elements B), wherein the thickness of the lower layer is 0.05 μm or more; the thickness of the upper layer is 0.005 μm or more and 0.6 μm or less; and in the upper layer, the relation between the ratio, the constituent elements A/(the constituent elements A+the constituent elements B) [mass %] (hereinafter, referred to as the proportion of Sn+In) and the plating thickness [μm] is given by

plating thickness≦8.2×(proportion of Sn+In)^−0.66 [herein, (the proportion of Sn+In)≧10 mass %].

The invention discloses a cooling polycarbonate composite material and a preparation method thereof as well as a preparation method of a daylight lamp holder bracket. The cooling polycarbonate composite material comprises the following raw materials by weight percent: 80-82wt% of polycarbonate, 5-15wt% of micron-scale aluminum oxide whisker fiber, 3-10wt% of micron-scale alumina, 3-10wt% of micron-scale magnesium oxide, 2-6wt% of compatilizer, 1-3wt% of a dispersant, 1-3wt% of a lubricating agent, 0.3-1wt% of a coupling agent, 0.5-1wt% of an antioxidant, and 0.5-1wt% of an anti-ultraviolet agent. The cooling polycarbonate composite material disclosed by the invention is good in mechanical property and chemical property, good in corrosion resistance and high-temperature resistance, good in product stability, convenient to process and mold, and environmental friendly, and can be recycled; the daylight lamp holder bracket prepared from the cooling polycarbonate composite material is low in surface temperature; a light-emitting diode (LED) is low in junction temperature, rapid to cool, and good in insulativity; the overall lamp is light in weight; the defect of short service life of the traditional product is removed; the insecurity factors generated when an aluminum substrate guides the cooling effect are removed.

The invention belongs to the research field of metal matrix composites and relates to a high thermal conductivity graphite whisker/copper composite and a preparation method thereof. The composite comprises two parts, namely matrix pure copper and plated reinforced phase high thermal conductivity graphite whisker, wherein the volume fraction of the pure copper is 40 to 70 percent, and the volume fraction of the plated graphite whisker is 30 to 60 percent. The composite adopts the following production process steps: firstly, the surface of graphite whisker is plated with copper or molybdenum byadopting a chemical plating or salt bath plating method, so as to form a plating with the thickness of 1 to 2 Mum; and secondly, the plated graphite whisker and copper powder are uniformly mixed in the proportion of (30 to 60) to (70 to 40), and then the mixture is sintered at 820 to 980 DEG C by adopting an SPS Spark Plasma Sintering powder metallurgic method, so as to prepare the graphite whisker/copper composite. The invention provides the preparation method of the graphite whisker/copper composite used in the electronic packaging field, and the graphite whisker/copper composite has the advantages of high thermal conductivity, controllable thermal expansion coefficient, high density, easiness in processing and the like, thereby meeting requirements in the modern electronic packaging field.