68results about How to "Avoid graphitization" patented technology

The invention relates to carbon paper and a preparation method thereof and particularly relates to special high-performance carbon paper for a gas diffusion layer of a fuel cell and a preparation method of the carbon paper. By taking short carbon fibers, plant fibers, heat bonding fibers and carbon black as raw materials, the carbon paper is prepared by the following steps: defibering, pulping and proportioning; then carrying out papermaking by adopting a wet-method papermaking process; and carrying out waterproof pigment coating treatment. The ratios of all the raw materials are as follows in parts by weight: 65-75 parts of the short carbon fibers, 10-15 parts of the plant fibers, 10-15 parts of the heat bonding fibers and 0-10 parts of the carbon black. According to the special high-performance carbon paper for the gas diffusion layer of the fuel cell and the preparation method of the carbon paper, a production process combining wet-method formation, hot pressing and coating is adopted and has the characteristics of simple process flow, easiness for controlling product quality, environment-friendly production process and the like; the material ratio of each raw material can be accurately controlled in the production so as to be good for controlling the product quality.

The invention discloses a method for producing a diamond tool for grinding a concrete floor, which comprises the following steps: proportional irregular glomerocryst diamond and man-made diamond are uniformly distributed on the surface of a tire casing; a gap between the diamond is filled with metallic bond, and according to the ratio by weight, the metallic bond comprises 40 to 70 percent of cobaltco, 10 to 20 percent of copper, 15 to 20 percent of tungsten carbide, 5 to 10 percent of stannum and 0.5 to 3 percent of trace element; the operation of cold press molding is carried out, sections formed by the cold press molding are delivered to a vacuum hot press sintering furnace to be sintered, and the temperature is kept from 850 DEG C to 900 DEG C and the pressure from 10 to 15 tons; and the sintered sections are welded on a metal base body. The diamond tool produced by the method not only can increase the grinding efficiency and maintain the stable performance, but also can greatly prolong the service life.

The invention discloses a diamond grinding wheel, which has multi-layer abrasive particle orderly arrangement, is high in bonding strength and is convenient to repair after being worn, and a production method thereof. The production method comprises steps of processing a grinding wheel basal body, cleaning and the like. According to the diamond grinding wheel and the production method thereof disclosed by the invention, a laser material increasing technology is adopted to accurately process, so that processing precision and processing quality are improved; a sandwich structure is adopted for sintering, so that the abrasive particles are prevented from moving, protruding height of the abrasive particles is guaranteed to be consistent, orderly arrangement of the diamond abrasive particles is realized, a chip space during grinding is great, grinding force is reduced, a grinding temperature is reduced, grinding efficiency is improved, and grinding surface quality is improved; power of a laser unit is controlled for controlling a sintering temperature, so that the diamond abrasive particles are prevented from graphitizing, and a metal bonder is combined with the diamond abrasive particles in a high-strength metallurgical mode; a manufacturing process further can be simplified; and the diamond grinding wheel is finished layer by layer after being worn, and then is continuously used, so that finishing is convenient, and the service life of the diamond grinding wheel is long.

The invention relates to an apparatus for forming SiC on a nucleus. The apparatus comprises a first enclosure (100) defined by at least one wall (102, 110, 112) and able to receive a SiC nucleus (122), a SiC powder reservoir (118) and means (120) for heating the enclosure and, according to the invention, the wall (102, 110, 112) is essentially covered by at least one SiC layer (116).

The invention relates to a method for improving the quality of diamond seed crystals with a hydrogen plasma multiple etching/annealing cyclic process, and relates to a method for improving diamond seed crystal quality. With prior arts, a method for improving diamond seed crystal quality has the defects of high time consumption and complicated operation. Seed crystal surface quality degradation can also be caused easily. The invention aims at solving the above problems. The method comprises the steps of 1, diamond seed crystal cleaning; 2, welding; 3, seed crystal placement; and 4, hydrogen plasma etching/annealing. With the hydrogen plasma etching/annealing treatment, crystal defect, surface and sub-surface damages on diamond seed crystal surfaces caused by mechanical polishing, and diamond seed crystal internal stress and defects can be removed at a same time in a same instrument; crystallinity can be improved, and high-quality seed crystals can be obtained; and the operation is greatly simplified, such that time and cost are saved. The method provided by the invention is applied in the technical field of crystal growth.

The invention relates to an additive manufacturing method for a diamond tool. The method includes the steps that a diamond abrasive particle layer is formed at first; then a thin laser brazing layer is formed on the upper surface of the diamond abrasive particle layer, and the step is executed repeatedly until multiple thin laser brazing layers are formed on the upper surface of the diamond abrasive particle layer to cover diamond abrasive particles; the steps are repeated, and accordingly (N-1) laser brazing diamond abrasive particle layers are obtained; and an Nth laser brazing diamond abrasive particle layer is obtained, the laser brazing process is completed, and thus the laser brazing diamond tool with N layers of abrasive particles is prepared. The invention further relates to the diamond tool prepared through the method. According to the additive manufacturing method for the diamond tool, paraxial jet diamond abrasive particles are adopted for conducting multi-layer laser brazing, burning loss oxidation and graphitization of the diamond abrasive particles in the brazing process are avoided, the service life of a laser brazing diamond grinding wheel is prolonged, and orderly distribution and automatic production of the abrasive materials can be realized easily.

The invention relates a method for laser brazing tool of monolayer diamond. The method comprises the following steps: providing a basal body of a diamond tool; coating a brazing material on the surface of a diamond tool basal body to prepare a diamond tool blank; providing a jetting system including a hopper and a spray gun connected with the hopper; providing diamond abrasive grains and placing the diamond abrasive grains into the hopper; providing a laser brazing system including a laser generator and a laser brazing working head; aligning the laser brazing working head and the spray gun to a tool blank surface; starting the laser brazing system and the jetting system, and doing synchronous motion of the laser brazing working head and the spray gun to ensure that focused laser beams produced by the laser brazing working head are positioned in front of the working head and are irradiated on the preposed brazing material so as to molten the brazing material; and after laser light spot, the diamond abrasive grains are sprayed by adopting the spray gun into a brazing molten tank. The diamond abrasive grains are jetted by adopting a paraxle to carry out laser brazing, so that burning oxidization and graphitization of the diamond abrasive grains during brazing are avoided.

The invention provides a method for preparing a diamond abrasive material tool with orderly distributed abrasive particles by utilizing a mask through single-layer chemical vapor deposition. The method comprises the following steps of after pretreating a substrate, coating a photoresist on the surface, and paving the mask on the surface of the photoresist; distributing diamond abrasive materials on the surface of the mask, vibrating the substrate, and enabling the abrasive materials to enter distribution holes of the mask; and removing excess diamond abrasive materials outside the distributionholes, taking the mask down, carrying out chemical vapor deposition on the substrate adhered with the diamond abrasive materials, forming a diamond coating, and obtaining the diamond abrasive material tool. Compared with the prior art, the method provided by the invention has the following beneficial effects that (1) the method provided by the invention can be used for preparing the tool with theorderly distributed diamond abrasive materials with the fine granularity being 100mum, and is suitable for precision grinding machining; and (2) the method provided by the invention is simple in adopted equipment, less in steps, simple and convenient to operate, and beneficial to mass production.

The invention discloses a preparation method of a diamond enhanced high-entropy alloy composite coating. The method comprises the following steps that a mechanical method is adopted for treating the surface of a workpiece in advance and carrying out oil and dust removing, Cu, Ni-Cr-B-Si, Co-Cr-B-Si and Fe-Cr-B-Si are subjected to ball milling and mixing to prepare high-entropy alloy powder, afterbeing mixed, the mixture is prefabricated on the surface of a steel base body and subjected to induction heating to prepare the high-entropy alloy coating, then under protection of inert gas Ar, heating is carried out, diamond with the particle diameter being 3*35 micrometers is pressed, and the diamond enhanced high-entropy alloy composite coating is prepared. The coating has higher hardness andwear resisting performance, the diamond is pressed at a high temperature, thus graphitizing of the diamond in the heating process is avoided, in addition, a small amount of carbide is formed on the interface of the diamond, and the connecting strength is improved. The high-entropy alloy base body and the diamond have the characteristics of high strength and high wear resistance, and thus the coating has good wear resisting performance and good corrosion resisting performance.

The invention belongs to the technical field of ceramics, and discloses high-thermal-conductivity and high-wear-resistance silicon nitride ceramic as well as a preparation method and application thereof. The preparation method of the silicon nitride ceramic comprises the following steps: adding diamond with a metal coating, Si3N4, a sintering aid MgO and Yb2O3 powder into ethanol and a Si3N4 ball-milling medium, carrying out ball-milling and mixing, and carrying out ball-milling and drying to obtain mixed powder; and heating the mixed powder to 1600-1700 DEG C under the axial pressure of 30-100 Mpa and under a protective atmosphere, conducting heat preservation, and carrying out spark plasma sintering. The silicon nitride ceramic provided by the invention has high thermal conductivity andwear resistance, good cutting performance and long cutting life, and can be applied to the field of ceramic cutters.

The invention discloses a method for preparing a diamond sintered body by using discharge plasmas in a sintering mode. The mass ratio of the total mass of silicon powder and titanium powder to the diamond is (1-1.5):1; the mass ratio of the silicon powder to the titanium powder is (0.9-3.5):1; the method comprises the following steps of: putting the raw materials into a steel ball-milling tank; further putting a corundum milling ball of 18mm in diameter into the steel ball-milling tank, wherein the ratio of the ball material to the raw materials is 2:1; sealing up the steel ball-milling tank and opening a vacuum valve so as to vacuum the steel ball-milling tank; putting the ball-milling tank into a planet type ball mill, wherein the rotation speed of the planet type ball mill is 300r/min and the inverse frequency is 30Hz; continuously ball-milling for 30minutes, subsequently taking down the ball-milling tank and cooling down; and carrying out SPS sintering on the mixture under 10-100MPa at 1,100-1,650 DEF C for 5-20minutes so as to obtain the diamond sintered body. The method is simple in process, short in sintering time and low in energy consumption; the sintered diamond sintered body is fine in crystal grain and uniform in structure, the bending strength is improved to 200-440MPa, and the compactness is increased to 80-98%.

The invention provides a preparation method of a diamond-ceramic composite material based on photocuring molding, which comprises the following steps: weighing diamond powder and titanium powder, and plating titanium on the surface of diamond through a molten salt method to obtain a diamond titanium-plated layer; coating the titanium-plated surface of the diamond with paraffin through a ball milling method, and obtaining a paraffin layer; weighing the secondarily coated diamond particles and glass phase ceramic powder, uniformly mixing in a ball mill, then drying in a drying oven, taking out and sieving to obtain diamond-glass phase ceramic mixed powder; putting the obtained mixed powder, light-cured resin, a dispersing agent and the like into a homogenizer, and uniformly mixing to obtain light-cured diamond-ceramic composite material slurry; then, performing DLP printing in an additive manufacturing technology; and carrying out thermal sintering to obtain the photo-cured DLP printed part containing the diamond-glass phase ceramic composite material. The part prepared through the method has the beneficial effects of being high in forming precision, high in shape complexity and good in comprehensive mechanical property.

The invention discloses a heat exchanger applicable to recovery of water heat from an ascension tube of a coke oven and belongs to the technical field of waste heat recovery. The heat exchanger comprises an inner tube, an outer tube and the heat exchange tube, and further comprises a fin, wherein the inner tube and the outer tube are concentrically arranged in a sleeving manner; the heat exchangetube is arranged between the inner tube and the outer tube, and connected to the inner tube through the fin; the cross section of the fin is designed to be an arc-shaped plate or a bent plate; and twofree ends of the fin are correspondingly connected with the inner tube and the heat exchange tube. According to the heat exchanger, the inner tube wall temperature is stabilized at 360 DEG C or above, so that the problem caused by the condensation of tar on the inner wall of the inner tube can be avoided, and the heat exchange efficiency of the heat exchanger can be guaranteed; and through the fin and the heat exchange tube which are arranged outside of the inner tube, the impact of thermal expansion on the structure of the heat exchanger can be effectively eliminated, the isolation of a heatexchange medium from coke oven gas can be achieved, and the potential safety hazard caused by the accidental leakage of the heat exchange medium or the coke oven gas can be avoided.

The invention discloses an efficient preparation method of a diamond/metal matrix composite material, and relates to a preparation method of a diamond/metal matrix composite material. The problems that an existing method for preparing a carbide coating on the surface of diamond is large in energy loss, graphitization of the diamond is prone to occurring, and the technology is complex are solved. The method comprises the following steps of weighing diamond powder with a metal coating, filling a graphite mold with the diamond powder, performing compacting, carrying out low-temperature diffusion treatment and high-temperature reaction treatment, and carrying out air pressure infiltration. According to the preparation method, a preheating temperature curve is changed, the diamond is subjected to low-temperature long-time diffusion and high-temperature short-time reaction, graphitization of the diamond is avoided through the high-temperature short-time reaction, a compact carbide coating is synthesized on the surface of the diamond in situ in the preparation process of the composite material, the energy loss is reduced, the process is simple, the efficiency is high, the product quality and stability are easy to control, the cost is low, and industrial production and application are easy to realize. The method is suitable for preparing the diamond/metal matrix composite material.

The invention belongs to the field of processing tools for stones and ceramics, and particularly relates to a self-lubricating diamond circular saw web. The circular saw web comprises a saw web base body, a diamond braze-welding base body which is brake-welded with diamond particles, and self-lubricating filler, wherein grooves are processed in the edge of the saw web base body at equal spacing; the diamond braze-welding base body is partially inserted into the grooves of the saw web base body for being fixed; the diamond braze-welding base body is partially exposed to the surface of the saw web base body; and the self-lubricating filler is filled in the exposed diamond braze-welding base body, so that the peripheral surface of the circular saw web is smooth and complete. A single-layer braze-welding diamond technology, an abrasive particle orderly arranging technology and a solid lubricating technology are applied to a manufacturing process of the diamond saw web, so that firm holdingof abrasive particles can be realized, and using efficiency of the abrasive particles can be improved; and meanwhile, diamond can be prevented from generating graphitization at a high temperature, and a plurality of problems in the using process of the diamond saw web can be effectively solved, so that using performance of the diamond saw web is improved.

The invention discloses welding equipment for welding first welded parts and second welded parts, which are oppositely arranged. The welding equipment comprises a worktable, a clamping tool, a laser module and a cooling system, wherein the second welded parts are arranged on the worktable; the clamping tool is connected to the worktable; the first welded parts are clamped on the clamping tool; fluxes are fixed between the first welded parts and the second welded parts; the laser module is connected to the worktable, and is arranged corresponding to the fluxes or the second welded parts; and the cooling system is arranged on the clamping tool and connected with the first welded parts for cooling the first welded parts. The welding equipment can improve the strength and the plasticity of thewelded parts after welding to prevent the brittle failure.

The invention relates to a ceramic bonding agent, a preparation method and application thereof and a diamond grinding tool. The preparation method comprises the following steps that raw materials areprovided, wherein the raw materials comprise zinc nitrate, lithium nitrate, aluminum nitrate, magnesium nitrate, zirconium oxide, silica sol, organic fuel, a dispersing agent and an organic carbon source; the raw materials are dissolved in a solvent to form a mixed solution, and then the mixed solution is atomized and subjected to a combustion reaction so as to obtain a combustion powder product;and heat preservation treatment is carried out on the combustion powder product in inert gas atmosphere, so that partial silicon oxide in the combustion powder product and carbon elementary substancesare subjected to a carbothermal reduction reaction and a silicon carbide nanometer crystal whisker is grown in situ, and then calcination treatment is carried out on the combustion powder product under oxidizing atmosphere, so that carbide except for the silicon carbide nanometer crystal whisker formed in the carbothermic reduction process is oxidized to obtain the ceramic bonding agent. The ceramic bonding agent prepared by the method is small in particle size, is uniformly mixed and uniformly doped with SiCnw, and is capable of reducing the sintering temperature of the diamond grinding tool, capable of improving bending strength of the diamond grinding tool and capable of prolonging the service life of the diamond grinding tool.

The invention provides an iron-based material electric field auxiliary machining machine tool and a machining method. The iron-based material electric field auxiliary machining machine tool comprisesa main shaft, a mounting piece, a diamond cutter and a power supply device, wherein the diamond cutter is mounted on the main shaft; the main shaft drives the diamond cutter to rotate; the mounting piece is opposite to the main shaft, and is used for mounting workpieces; and the power supply device is used for introducing variable currents into the workpieces, so that electrons in the workpieces are in a disordered state. In the iron-based material electric field auxiliary machining machine tool and the machining method, the power supply device is provided for introducing the variable currentsinto the workpieces, so that the electrons in the workpieces are in the disordered state, the electron pairing combination is inhibited, and the purpose of inhibiting graphitization of the diamond cutter is achieved; and the iron-based material electric field auxiliary machining machine tool is better in inhibition effect, can be applied to long-distance cutting, needs no complex process requirements and expensive equipment, and is lower in cost.