34results about How to "Fine grain size" patented technology

The present invention belongs to an activated sintering method of a high-density aplitic non-magnetic Tungsten-Cu alloy. Tungsten-Cu composite powders are adopted as raw materials with an average particle size of less than 500nms, and the average size of the tungsten particles is less than 300nms. The base bodies of needed shapes and sizes are prepared adopting conventional moulding method and directly sent into a welding furnace to be sintered in a mixed atmosphere of protection and reducibility or in an atmosphere of reducibility. The sintering temperature is 1100-1340 degrees Celsius system, the heat holding time is 40-60 minutes and the present invention adulterates no activating agents. The prepared aplitic Tungsten-Cu alloy adopting the present invention is characterized in that the grain granularity is fine, the average grain size of tungsten is less than or equal to 800nms, the organizational structure is evenly distributed and the relative density of the alloy is more than 99 percent. The high density Tungsten-Cu alloy prepared using the invention has an excellent mechanical property and thermal conductivity, guards against the aliquation of copper efficiently, and is fine in granularity and high in intensity, plasticity and thermal conductivity. The invention is simple in technics, easy to control, pollution-free, low in investment cost, low in energy consumption and applicable to a mass industrial production.

There is provided a novel bearing steel composition and a method of forming a bearing. The bearing steel composition comprises: Carbon 0.4 to 0.8 wt%; Nitrogen 0.1 to 0.2 wt%; Chromium 12 to 18 wt%; Molybdenum 0.7 to 1.3 wt%; Silicon 0.3 to 1 wt%; Manganese 0.2 to 0.8 wt%; and Iron 78 to 86.3 wt%.

The invention discloses a novel build-up welding alloy in order to solve the problem that aluminium composite materials have coarsening structure and is difficult to be controlled by the preparation process. The build-up welding alloy comprises , Ni, C, Co, Nb, Cr, Fe, Ti, Al and W, and mass percents of each component are as follows: rare earths: 6-8%; Ni: 45-48%; C: 0.6%; Co: 6-8%; Nb: 4%; Cr: 4-6%; Fe: 2-3%; Ti: 0.8-1.2%; Al: 4%;the residuel of W; in which, rare earths is yttria(Y2O3) or cesium (Cs), C is added in the form of graphite. The disclosed build-up welding alloy of the invention, as fused coating metal, is build-up welded on the surface of aluminium alloy based body using laser build-up welding arts to produce fine crystal grain surface aluminium alloy composite materials, and the surface of aluminium alloy product is intensified and improved.

The invention provides an alloy magnetic material and a preparation method thereof, and belongs to the field of metal materials. The alloy magnetic material comprises the following components in percentage by weight: 29 to 33 percent of Nd, 0.9 to 1.3 percent of Cu, 0.9 to 1.3 percent of Al, 0.06 to 0.08 percent of Nb, 0.1 to 0.2 percent of Co, 0.9 to 1.2 percent of Ce, 0.9 to 1.2 percent of B, 2 to 6 percent of Dy and the balance of Fe. The preparation method comprises the following steps of: proportioning the components of the alloy magnetic material, preparing iron alloy powder, preparing composite aluminum-copper alloy powder, mixing the iron alloy powder and the composite aluminum-copper alloy powder, forming by using a highly-oriented magnetic field, performing cold isostatic pressing, performing vacuum high temperature sintering, performing double tempering to obtain the alloy magnetic material. The alloy magnetic material is high in magnetic property and low in material cost; and the preparation method for the alloy magnetic material is simple, low in production cost, safely operated and suitable for industrial production.

The invention discloses an antifreeze concrete, and belongs to the technical field of architecture construction. The antifreeze concrete comprises the components of cement, aggregate, fly ash, superfine slag powder, antifreeze water reducing agent and water, wherein the antifreeze water reducing agent is composed of, by weight, 40-50% of microcrystalline muscovite powder, 15-25% of ethylene bi-stearamide, 10-20% of triterpenoid saponins, 5-10% of bentonite, and 5-10% of naphthalene sulfonate. When the antifreeze water reducing agent is added to the concrete, on the one hand the compactness of the concrete can be greatly improved, on the other hand the average air void spacing coefficient and water binder ratio can be significantly reduced, the average air void spacing coefficient can be reduced to 20 micro meters or below, the water binder ratio can be reduced to 0.20 or below, in the meantime the strength of the concrete is also greatly improved, and the strength can reach C90 or above, so that excellent freeze resistance performance can be obtained; the antifreeze concrete is particularly suitable for use in the cold north or underground, and good engineering quality is guaranteed.

The invention develops a preparation method of a hierarchical porous alumina foam ceramic comparable to aerogel. The method includes the steps of: 1) preparing nano aluminum sol particles; 2) adding asurfactant into a suspensoid of the aluminum sol particles prepared in step 1) to obtain a sol suspensoid; 3) adjusting the pH of the sol suspensoid obtained in step 2) to 4-10; 4) foaming the product obtained in step 3) by mechanical agitation to obtain an ultra-stable aluminum sol foam slurry; and 5) drying the slurry obtained in step 4) to obtain the alumina porous ceramic. The foam structurehas uniform and complete air holes, and adopts tens of microns of closed pores based first-level pores as the main body, and the pore wall has a mesoporous second-level pore structure. Compared with the existing foam ceramics, the new material has higher specific surface area and air hole rate, and is comparable to aerogel as a light heat insulation material.

The invention discloses an impermeable concrete, and belongs to the technical field of building civil engineering. The impermeable concrete is composed of cement, aggregate, fly ash, bentonite, admixtures and water, wherein the admixtures are prepared from, by mass, 30%-40% oyster shell powder, 15%-25% ethylene bis stearamide, 10%-20% triterpenoid saponin, 6%-12% triethanolamine, 5%-10% bentonite,3%-6% dodecyl dihydroxyethyl betaine and 2%-5% naphthalene sulfonate. According to the impermeable concrete, the admixtures are added, the freeze prevention and freeze resistance performance are guaranteed, at the same time, the anti-permeability performance is greatly improved, the anti-permeability grade of the impermeable concrete reaches above P12, and the impermeable concrete is especially suitable for the case of concrete impermeability requirements such as buildings in the cold north.

The invention discloses a technology for manufacturing a low-temperature mold pressing tee through an X80 steel plate. According to the technology, a tee pipe fitting is prepared through the X80 steelplate by combining a welding technology with a pressing forming technology, the grain size and strength loss allowances caused by multiple times of heating and long heating time in the machining process are increased, and the tee pipe fitting can be normally used for a long time in the -45 DEG C extremely cold weather. The tee pipe fitting prepared through the technology has the small grain size,high strength and low welding crack sensitivity coefficient, the homogeneity degree of all parts of the product is greatly improved, and the tee pipe fitting can be suitable for the -45 DEG C operating environment.

The invention provides a polycrystalline diamond combined with a compound generated through in-situ reaction and a preparation method of the polycrystalline diamond and belongs to the technical field of superhard composite materials. The preparation method comprises the following steps: carrying out ball milling on Ti powder, Si powder and nano-diamond, and carrying out mechanical alloying to obtain a binding agent material, wherein the molar ratio of the Ti powder to the Si powder is equal to 3, and the molar ratio of the nano-diamond to the Si powder is greater than 2 and is less than or equal to 5; and mixing the binding agent material with micron diamond, pre-pressing the obtained mixture, and carrying out high-temperature and high-pressure sintering on the obtained pre-pressed blank to obtain the polycrystalline diamond combined with the compound generated through in-situ reaction. Due to excessive addition of the nano-diamond and high-pressure environment, the nano-diamond is left after reacting with Ti and Si and can be reserved; and the problem that Ti, Si and compounds thereof which are not completely reacted are easily left in a shed frame area away from the diamond when Si, Ti, B, Ni are added in a traditional PCD preparation method and soft spots are left is solved.

The invention relates to a system and method for producing Inconel composite alloys by double-process ball making, wherein the system includes: a crushing and screening device, a first mixing device, a ball pressing device and a first drying device connected in sequence; The ore grinding device, the second mixing device, the pelletizing device and the second drying device; the rotary hearth furnace with a double-layer material distribution system connected to the first drying device and the second drying device respectively; A smelting device connected to a rotary hearth furnace. The present invention uses the mixed pellets of chromite and lateritic nickel ore as raw material, and adopts double-layer material distribution system and double-process ball making method according to the unique characteristics of raw materials, strictly controls the particle size and diameter of the two raw material pellets, and improves the speed of rotation. Heat utilization and production capacity of the hearth furnace.

The invention discloses a sol-gel preparation method of aluminum hydroxide. The preparation method comprises the following steps: step one, preparing an aluminum chloride solution from aluminum chloride and deionized water, and then dropwise adding hydrochloric acid into the solution to adjust the pH value; step two, adding the prepared solution into a reaction flask provided with a reflux apparatus, a magnet stirrer, and a temperature meter, carrying out reactions in a water bath at a constant temperature, then heating under stirring, and refluxing; step three, after the reactions, cooling to the room temperature, filtering, washing the reaction product by acetone, and then drying the reaction product in a baking oven so as to obtain the aluminum hydroxide powder. In the provided preparation method, the raw materials are dispersed into a solvent to prepare a solution with low viscosity in advance, thus the uniformity in the molecular level can be achieved in a very short time, compared to the reactions performed in a solid, and the chemical reactions can be carried out more easily in a solution, so the synthesis temperature is lower, moreover, the obtained product is finer, and the flame retardant effect is better.

The invention relates to the technical field of refractory materials. The magnesium aluminate spinel crucible for the high-temperature alloy comprises the following raw materials: magnesium aluminatespinel, SiC, graphite, an antioxidant and a binding agent, the magnesium aluminate spinel comprises magnesium aluminate spinel particles and magnesium aluminate spinel powder, and the SiC comprises SiC particles and SiC powder; the method comprises the following steps: putting the raw materials into a stirrer according to a weight ratio, and stirring to obtain pug; putting the stirred pug into a sealed container for ageing; putting the aged pug into a rubber mold, putting the rubber mold into an isostatic pressing machine, and carrying out pressure molding to obtain a semi-finished product; putting the formed semi-finished product into a drying kiln to be dried; and putting the dried semi-finished product into a firing kiln, and firing to obtain the finished crucible. The crucible disclosed by the invention has high thermal shock resistance and high erosion resistance, and the service life of the crucible at the use temperature of not higher than 1300 DEG C can reach 100 heat times orabove.

The invention provides a high-strength stainless steel wire for interventional medical treatment. The high-strength stainless steel wire comprises the following chemical components in percentage by mass: 0.01%-0.09% of C, 0.01%-1.00% of Si, 0.01%-2.00% of Mn, 0.005%-0.05% of P, 0.01%-0.30% of S, 7%-15% of Ni, 14%-20% of Cr, 0.01%-0.08% of N, 0.01%-0.5% of La+Ce, 0.01%-1% of Y and the balance of Fe, wherein the equivalent weight of Ni is less than or equal to 35, and the equivalent weight of Ni is equal to Ni+0.65Cr+0.98Mo+1.05Mn+0.35Si+12.6 C. A preparation method of the stainless steel wire comprises the steps of vacuum melting, blank forging, wire rough blank drawing and wire drawing. Stainless steel is based on the chemical components, and a certain Ni equivalent is guaranteed. A certain martensite volume fraction is obtained by designing the pass compression amount, the drawing speed and the drawing temperature, so that the strength is regulated and controlled. A martensite structure with a certain crystal face orientation is obtained by combining a drawing die and the pass sectional area compression amount. In addition, through the grain refining effect of rare earth elements and the precipitation strengthening effect of in-situ authigenic rare earth nitride, the high-strength steel wire is finally obtained.

The invention provides an overlay coating on a blade substrate and a preparation method thereof. The overlay coating comprises at least four alternately deposited TiN layers and TiCN layers, at leastfive alternately deposited TiCNO layer and TiN layers, an AlTiCNO layer, an aluminum oxide nucleating layer and an aluminum oxide coating, wherein the thickness of each of the TiN layers and TiCN layers is 0.5-1.0 [mu]m, the thickness of each of the TiCNO layer and TiN layers is 0.5-1.0 [mu]m, the thickness of the AlTiCNO layer is 0.1-1.5 [mu]m, the thickness of the aluminum oxide nucleating layeris 0.1-0.8 [mu]m, and the thickness of the aluminum oxide coating is 3-10 [mu]m. The preparation method comprises the step of depositing the coatings successively on a hard alloy blade at corresponding temperatures, atmospheres and air pressures by means of a chemical vapor deposition method. The blade coated by the coating is higher in hardness and wear resistance, higher in wear-resistant degree and longer in service life.

The invention discloses a WCrRuTaV refractory high-entropy hard alloy with NbCr2 as a binder and a preparation method of the WCrRuTaV refractory high-entropy hard alloy, and belongs to the technical field of hard alloy materials. Refractory metal elements W, Cr, Ru, Ta and V are adopted as raw materials, and high-entropy hard alloy powder is prepared through mechanical alloying; and the high-entropy hard alloy powder and the NbCr2 powder are evenly mixed and then subjected to spark plasma sintering, and the block hard alloy material is obtained. The NbCr2-bonded WCrRuTaV refractory high-entropy hard alloy obtained through the method has the superfine grain size and the high density, meanwhile, the hard alloy is uniform in component distribution and excellent in performance, and therefore the NbCr2-bonded WCrRuTaV refractory high-entropy hard alloy has the good application prospect.