39 results about "Homogeneous microstructure" patented technology

The invention concerns novel varistors based on zinc oxide and a method for making same, which consists in using as base products nanocrystalline powders obtained by high-intensity mechanical grinding and in subjecting the mixture resulting from said nanocrystalline powders a consolidating treatment such as sintering, in suitably selected temperature and time conditions so as to retain the smallest possible grain size of ZnO. The resulting varistors have a very fine homogeneous microstructure and an average grain size characteristically not more than 3pm, i.e. five times smaller than standard materials. Said novel varistors have a larger number of grain boundaries per unit length unit and therefore a much higher breakdown voltage. Said voltage is characteristically higher than 10 kV/cm and can reach 17 kV/cm which is almost one order of magnitude above the breakdown voltage of standard varistors. The non-linearity coefficient of the current-voltage curve is also improved, and is greater than 20 and can reach values as high as 60. Moreover, the leakage currents below the breakdown voltage of said varistors, are much lower.

Warhead structures and features are fabricated using direct manufacturing technologies, a method for fabricating bulk warhead structures by sequential and additive deposition of melted feedstock layers. Suitable energy sources for melting the feedstock can be various high energy density technologies including laser, electron beam, plasma arc deposition, and the like. The high energy density in combination with high cooling rates results in structures with homogeneous microstructures. The feedstock can be in the form of wire or powder and is applied to a substrate by introduction to a molten pool on the substrate, accumulating to additively combine with the substrate. The approach provides for warhead structures with singular and combined unique features to include: integral constructions, tailored fragmentation patterns, use of dissimilar materials for special effects, and variable material property constructions for enhanced performance.

High purity niobium metals and alloys containing the same are described. The niobium metal preferably has a purity of at least 99.99% and more preferably at least 99.999%. In addition, niobium metal and alloys thereof are described, which either have a grain size of about 150 microns or less, or a texture in which a (100) intensity within any 5% increment of thickness is less than about 30 random, or an incremental log ratio of (111):(100) intensity of greater than about -4.0, or any combination of these properties. Also described are articles and components made from the niobium metal which include, but are not limited to, sputtering targets, capacitor cans, resistive film layers, wire, and the like. Also disclosed is a process for making the high purity niobium metal which includes the step of reacting a salt-containing niobium and a metal salt along with at least one compound capable of reducing the salt-containing niobium to niobium and in a reaction container. The reaction container or liner in the reaction container and the agitator or liner on the agitator are made from a metal material having the same or higher vapor pressure of melted niobium. The high purity niobium product preferably has a fine and uniform microstructure.

The invention discloses a method for preparing Ni-W alloy by vacuum sintering, comprising the following steps of: using a Ni powder with its purity being no less than 99.9% and a W powder with its purity being no less than 99.9% as raw materials, carrying out ball milling on the two powders at different weight ratio at different time and at different ball milling ratio; compacting, carrying out vacuum sintering on the pressed compact, cooling in furnace, and finally machining the Ni-W alloy into a finished product. The method provided by the invention has simple preparation technology and requires low production cost. By the adoption of the method, nickel-tungsten alloy with high density and homogeneous microstructure can be prepared.

The invention belongs to the technical field of structural optimization design, and discloses a multi-scale topology optimization method based on an agent model. The method comprises the following steps: (1) optimizing by adopting a topological optimization method based on a parameterized level set to obtain optimal topological configurations of various prototype microstructures; (2) carrying outinterpolation on the optimized level set function of the prototype microstructure to obtain equivalent attributes of the non-uniform microstructure, and then constructing a prediction model by takingthe non-uniform microstructure as a sample point to predict the equivalent attributes of all macroscopic units in a macroscopic structure domain; and (3) optimizing material distribution in the macrostructure domain by adopting a variable thickness method, so that the performance of the macrostructure is optimal. By means of the method, the geometric and pointwise macroscopic unit configurations of the macroscopic structure and the joint optimization of the positions of the macroscopic unit configurations in the macroscopic structure domain are achieved, the material potential is brought intoplay to the maximum extent with the low calculation cost, material consumption is saved, and the cost is reduced.

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal or vertical direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting. A multiple layer ingot product is also provided comprising a base alloy layer and at least a first additional alloy layer, the two layers having different alloy compositions, where the first additional alloy layer is bonded directly to the base alloy layer by applying the first additional alloy in the molten state to the surface of the base alloy while the surface temperature of the base alloy is lower than the liquidus temperature and greater than eutectic temperature of the base alloy −50 degrees Celsuis.

Molten metal is injected uniformly into a horizontal mold from a feed chamber in a horizontal direction at a controlled rate, directly on top of the metal already within the mold. A cooling medium is applied to the bottom surface of the mold, with the type and flow rate of the cooling medium being varied to produce a controlled cooling rate throughout the casting process. The rate of introduction of molten metal and the flow rate of the cooling medium are both controlled to produce a relatively uniform solidification rate within the mold, thereby producing a uniform microstructure throughout the casting, and low stresses throughout the casting.

A dental all-ceramic restoration and manufacturing method thereof; the outer surface of the dental all-ceramic restoration has neither visible marks remaining from the removal of the connecting bars (7) nor local grinding traces and chipping, and is smooth with uniform structure. The manufacturing method thereof is wet-forming or milling. No connecting bars are needed to connect the dental restoration bodies (3) with a surrounding mould blank or ceramic blank. This eliminates the need for manually cutting off the connecting bars (7) to separate the forming body from the surrounding ceramic blank, further grinding and polishing process to treat the excessively rough outer surface, and thereby reducing the risk of chipping and premature failure. In the manufacturing processes thereof, the hardened ceramic green body (2) made by wet-forming technique has more homogenous microstructure and less particle packing defects than the dry-pressed blanks and partially sintered blanks. Furthermore, higher surface smoothness can be obtained by milling unsintered hardened ceramic green body than by milling partially sintered blanks. The dental all-ceramic restoration has a high degree of surface finish, and can be directly used without polishing, veneering or glazing.

The invention belongs to the technical field of high-performance composite materials, and specifically relates to a composite material of modified boride filled with epoxy resin, more specifically to a composite material which is obtained by modifying a high-performance ceramic powder surface by an organic functional group and filling organic resin and has homogeneous microstructure and excellent heat resistance and wear resistance. Through an in situ polymerization method for preparation, bisphenol A is firstly dissolved in a NaOH solution completely, the boride powder with the surface modified by the organic functional group is added, ultrasonic oscillation and intense agitation for dispersion are carried out, chloropropylene oxide is then added for polymerization, a curing agent is added, and curing molding is carried out at a high temperature. The prepared composite material of modified boride filled with epoxy resin has structural features of homogeneous material microstructure and excellent heat resistance and wear resistance, and can be applied in high-temperature wear-resistant members required in the industrial fields of aviation, automobile and the like.

The invention discloses a preparation method for a resin binder and diamond grinding tool with a homogeneous microstructure and belongs to the technical field of abrasives, grinding tools and grinding. The preparation method comprises the main steps that a resin binder and a diamond abrasive are treated with surfactant and then are mixed, and then the mixture is mixed with glass hollow microspheres or ceramic hollow spheres evenly coated with a layer of coal ash; filler is put in; die filling is conducted, and hot press molding is adopted; and finally with-die solidification is conducted, andthe resin binder and diamond grinding tool with the homogeneous microstructure is obtained. The preparation method has the beneficial effects that the grinding tool is provided with homogeneous air holes, and chip removal and chip holding are facilitated for the grinding tool; and the grinding tool is high in holding force, good in sharpness and high in grinding efficiency and has a good blade sharpening effect, and workpiece surface machining precision is high.

The invention aims to solve the problem existing in the prior art to prepare a graphene coated silicon carbide composite material, provides a graphene/silicon carbide composite material and a preparation method thereof, and belongs to the technical field of graphene composite materials. The method comprises the steps that laminated graphite with the appropriate size is appropriately mixed with nano silicon carbide particle powder, ethyl alcohol and distilled water are added to serve as a grinding medium and a process control reagent, sufficiently ball milling is conducted for a certain periodof time, and the nano composite material with a graphene coated silicon carbide core-shell structure is prepared. Graphene does not need to be prepared firstly, and preparation of the graphene/siliconcarbide composite material is completed under the ball milling condition. In addition, no dangerous reagents is used in the preparation process, and no high temperature and high pressure process exists. The prepared product has the more uniform microstructure and the isotropous performance.

The invention discloses a hard-tissue bio-medical in-situ synthesized zirconium matrix composite material and a preparation method thereof. The hard-tissue bio-medical in-situ synthesized zirconium matrix composite material comprises the following components by weight percent: 3.5-4.5 percent of copper, 0.1-1.20 percent of niobium and the balance of zirconium sponge. According to the preparation method, the raw materials are weighed according to the weight percents of the components, mixed fully, then smelted by using a non-consumable vacuum arc smelting furnace, and cooled to obtain metal ingots with a homogeneous microstructure. The hard-tissue bio-medical in-situ synthesized zirconium matrix composite material has the advantages of traditional medical titanium alloy, and simultaneously solves the problem that the young's modulus of the traditional medical titanium alloy does not match with the natural bones of the human body as well as the problem of damage to human bodies caused by the mismatching mechanical performance of substitute materials; according to the hard-tissue bio-medical in-situ synthesized zirconium matrix composite material and the preparation method thereof, zirconium matrix is strengthened by using in-situ synthesized Zr3Cu as the reinforcing phase and niobium as the alloying element, the compression strength of the zirconium matrix composite material is effectively improved, and meanwhile the compression strength, the plasticity, the young's modulus and the like of the zirconium matrix composite material are changed by adjusting the content of niobium.

A high-speed electroplating method is provided. The high-speed electroplating method includes the following steps: providing a substrate containing a conductive layer on its surface; coating a dry-film photoresist on the conductive layer of the substrate, and patterning the dry-film photoresist; performing a pretreatment process to clean the substrate; disposing the substrate in an electroplating solution; turning on an ultrasonic oscillation machine to vibrate the electroplating solution, and turning on a jet flow device to agitate the electroplating solution, and performing a pre-electroplating process with a plating current density of 0.5 A/dm² to 5 A/dm², and then performing a high-speed electroplating process with a plating current density of 6 A/dm² to 100 A/dm²; depositing a conductive pillar on areas without the dry-film photoresist; and removing the dry-film photoresist being coated on the conductive layer of the substrate. Thus, the high-speed electroplating method can achieve high-speed electrodeposition with uniform microstructures.

An ethylene/butadiene copolymer comprising statistically distributed ethylene units butadiene units, and trans-1,2-cyclohexane units is provided. The molar fraction of ethylene units in the copolymer is greater than or equal to 50%, relative to the total number of moles of ethylene, butadiene and trans-1,2-cyclohexane units. The microstructure of the copolymer is homogeneous.

A process for preparing such a copolymer and also to the uses of this copolymer, in particular in rubber compositions for tires, is also provided.