464 results about "Grain growth" patented technology

The invention provides a metal material surface difference analysis method which comprises the following steps: calculating Gibbs free energy at different temperatures by adopting a thermodynamic model according to chemical components and an initial microstructure of a material, and drawing a time-temperature-transformation curve of the material through phase diagram analysis software, obtaining a grain growth kinetic parameter and a recrystallization temperature interval; inputting data information of strength, hardness and toughness in different application scenes by utilizing the established multi-objective optimization model, and searching optimal grain size distribution through a genetic algorithm to obtain an optimal microstructure for balancing various performance indexes; according to the optimal microstructure, a heat treatment process route is reversely designed, finite element software is adopted to simulate temperature field and stress field distribution in the heat treatment process, and control parameters of heating, heat preservation and cooling are determined through iterative optimization.

The invention relates to the technical field of hot galvanizing, and discloses an automobile hot galvanizing process parameter optimization method and system based on artificial intelligence, and the method comprises the steps: carrying out window division processing on initial cooling parameters, constructing a cooling rate matrix, and finely depicting heat exchange states of different cooling sections; the problem of insufficient cooling control precision under different cooling speed alternating conditions is solved, a microscopic image is combined to extract the grain main axis direction, calculate the mean value and range of included angles, generate a consistency index set and quantitatively describe the dispersion problem in the grain growth direction, the cooling speed and the consistency index are jointly matched, and a cooling speed structure offset matrix is constructed. The method comprises the following steps: identifying a space mutation region, accurately positioning abnormal coarse or abnormal arrangement positions of crystal grains, and finally screening target cooling parameters according to a cooling index value corresponding to an abnormal region to realize local adjustment of a cooling process, thereby reducing the abnormal growth rate of the crystal grains and improving the direction consistency of the crystal grains.

The invention discloses pressureless sintered aluminum nitride ceramic as well as a preparation method and application thereof. The preparation method comprises the following steps: ball-milling and mixing micron-sized aluminum nitride, a sintering aid, nano-sized molybdenum powder, a dispersing agent, a binder and an organic solvent to prepare slurry; and drying the slurry, granulating, forming, dumping and sintering to obtain the pressureless sintered aluminum nitride ceramic. Wherein the sintering aid is a combination of samarium fluoride and yttrium fluoride. According to the preparation method, oxygen is removed at a low temperature by virtue of strong affinity of the nanoscale molybdenum powder and oxygen, the nanoscale molybdenum powder and the sintering aid jointly play a role in liquid-phase sintering assistance at a high temperature, densified sintering is realized and grain growth is inhibited by adopting pressureless sintering at a relatively low sintering temperature, the aluminum nitride ceramic with both heat conduction and strength is obtained, and meanwhile, a low-resistance second phase is generated; the resistivity of the aluminum nitride ceramic is adjusted while the heat conduction characteristic of the aluminum nitride ceramic is improved, the electrical conductivity of the aluminum nitride material is improved, and finally the aluminum nitride ceramic with high heat conduction and bending strength and moderate resistivity is obtained to meet the use requirements of electrostatic chucks.

The invention relates to the technical field of alloy materials, and discloses a preparation method of a nano WC-Co hard alloy for micro drilling, the nano WC-Co hard alloy comprises the following raw materials by weight: 83-92 wt% of nano tungsten carbide, 7-17 wt% of ultrafine cobalt oxide powder, 0-1.5 wt% of a hard alloy grain growth inhibitor, and 0.2-3 wt% of a forming agent; the method comprises the following steps: 1, mixing nano tungsten carbide, superfine cobalt oxide powder, vanadium carbide and a forming agent, and adjusting a carbon balance point in the powder to be mixed by using free carbon black; 2, sequentially putting the powder and a forming agent into a ball mill, and mixing the materials by taking absolute ethyl alcohol as a ball milling medium; the superfine cobalt oxide powder is used for replacing superfine cobalt powder, so that the extension area of cobalt element powder is increased, the problem that the cobalt powder is extended into a sheet shape is avoided, the cobalt pool phenomenon is effectively reduced, meanwhile, crystal grain growth inhibition carbides are increased, the phenomenon that a binding phase in hard alloy is not uniform is avoided, the service life of the finished micro-small-diameter drill bit special for the PCB is guaranteed, and the service life of the finished micro-small-diameter drill bit special for the PCB is prolonged. And the product quality is further improved.

The invention belongs to the technical field of silicon nitride ceramic substrates, and particularly relates to a high-thermal-conductivity and high-breaking-strength silicon nitride substrate and a sintering method and application thereof. In order to simultaneously improve the thermal conductivity and the breaking strength of the existing silicon nitride ceramic substrate and ensure the stability and the consistency of the performance during the production of the silicon nitride substrate, the method comprises the following steps: coating the surface of a silicon nitride ceramic biscuit subjected to tape casting with isolation powder, carrying out nitrogen or air atmosphere glue removal treatment, and then sintering; in the sintering process, the cooling process is optimized, a multi-temperature heat preservation platform is arranged above the liquid phase conversion temperature, grain growth and grain boundary composition of the silicon nitride ceramic are regulated and controlled, grain size distribution of the silicon nitride ceramic is made to be more uniform, the grain boundary structure is made to be more optimized, and the heat conductivity coefficient and breaking strength of the substrate are remarkably improved. Meanwhile, the uniformity of a temperature field in the sintering furnace can be greatly improved through the sintering method, it is ensured that the product can reach the consistent performance standard in different areas, and the stability and reliability of the product are improved.

The invention discloses a preparation method of thermal shock resistant magnesium aluminate spinel transparent ceramic, and belongs to the technical field of ceramic materials. The preparation method comprises the following steps: (1) synthesizing crystalline MgAl2O4 nano powder by adopting an additive-free hydrothermal method; (2) depolymerizing the powder, performing water-based gel casting to prepare a green body, and performing staged debonding treatment on the green body; (3) carrying out two-step vacuum presintering on the green body; (4) carrying out hot isostatic pressing densification treatment in a subgrain growth temperature region of 1380-1420 DEG C; and (5) carrying out annealing treatment on the densified ceramic. High-purity crystalline powder is synthesized through an additive-free hydrothermal method, grain boundary impurities are eliminated, and the intermediate infrared transmittance is remarkably improved; by combining the synergistic effect of optimized two-step pre-sintering and hot isostatic pressing in a sub-grain region, precise refinement of the grain size is realized; and finally, the bending strength, the fracture toughness and the critical thermal shock temperature difference of the material are greatly improved under the strengthening mechanism of ultrafine grains and defect-free grain boundaries.

The invention discloses a preparation method of a superfine WC-Co hard alloy. 89.8-90% wt of superfine tungsten carbide, 9% wt of superfine Co powder and 1-1.2% wt of composite additive chromium carbide and vanadium carbide are adopted; wherein the weight ratio of chromium carbide to vanadium carbide is 1 / 2; ball-milling the raw materials to obtain a mixture; and the pressed blank is subjected to a specific oscillation pressure and rapid cooling sintering process, the contact form and interface state among particles are improved, the density of the hard alloy is improved, WC grain growth is inhibited, flowing of binding phase Co is promoted, the structure and mechanical properties of the alloy are remarkably improved, and the nanocrystalline WC-Co hard alloy with high strength and high density is obtained.

The invention relates to a high-hardenability gear steel bar for a new energy automobile and a manufacturing method of the high-hardenability gear steel bar. The high-hardenability gear steel bar comprises the following chemical components in percentage by mass: 0.17-0.25% of C, less than or equal to 0.37% of Si, 0.50-0.90% of Mn, 0.85-1.25% of Cr, less than or equal to 0.025% of P, less than or equal to 0.030% of S, less than or equal to 0.30% of Cu, 0.02-0.06% of Ti, 0.02-0.05% of Al, less than or equal to 0.30% of Ni, 0.15-0.45% of Mo, 0.0005-0.0020% of B, 0.020-0.080% of Nb, less than or equal to 0.0030% of Ca, 0.0090-0.0150% of N, less than or equal to The production and manufacturing process comprises the steps of converter treatment, external refining, vacuum degassing, continuous casting, continuous rolling, shearing or saw cutting, stack cooling and finishing flaw detection. According to the invention, fine Nb (C, N) and (Nb, Ti) (C, N) particles are precipitated by microalloying Nb and Ti, the growth of crystal grains is effectively inhibited, and meanwhile, the hardenability of the material is improved by adding a proper amount of B element. According to the invention, Nb, Ti and B are adopted for composite microalloying at the same time, so that the fine-grain and high-hardenability gear steel material is obtained.

The invention belongs to the technical field of photovoltaic solar materials, and particularly relates to a high-conversion-efficiency perovskite precursor material and a preparation method thereof. The high-conversion-efficiency perovskite precursor material is composed of phenyl ammonium cesium composite cations, metal halide, an additive, a nuclear auxiliary agent and a solvent. By compounding phenylethyl ammonium iodide and cesium iodide, phenylammonium and cesium cations are introduced into perovskite crystal lattices, organic-inorganic balance of the material is optimized, phenylammonium promotes formation of a quasi-two-dimensional structure, and damp-heat stability is enhanced; cesium ions fill A-site gaps, so that crystal lattices are tighter, and the thermal stability and the photoelectric conversion efficiency are improved; the synergistic matching addition of the metal halide realizes band gap regulation and control and spectrum matching, and quaternary ammonium salt adjusts nucleation and grain growth, so that a uniform film structure is ensured, and defects are reduced; and guanidine salt passivates defects after crystal growth, stabilizes crystal lattices, and improves charge life and device efficiency.

The invention belongs to the technical field of lithium ion battery materials, and discloses a preparation method of a high-first-effect small-particle single-crystal ultrahigh-nickel ternary positive electrode material. The method comprises the following steps: firstly, uniformly mixing an ultrahigh nickel ternary precursor with a lithium source and a tungsten source, performing mechanical densification and pressing to obtain a blocky solid, and then performing four-section program temperature control calcination to obtain a target material. The interface fusion resistance of single crystal growth can be reduced through mechanical densification; a part of the tungsten element forms a Li2WO4 coating layer, and a part of the dopant phase replaces Ni < 2 + >, so that grain growth can be inhibited, a crystal structure can be stabilized, and the first effect is improved; and the microstructure of the material can be accurately regulated and controlled through four-section temperature-controlled calcination. Through a coating-doping-single crystallization synergistic strategy, the electrochemical performance of the material in liquid and sulfide-based all-solid-state batteries is remarkably improved, the process is controllable, and the application prospect is wide.

The present invention relates to the technical field of hard alloys. Disclosed are a binder-phase-free hard alloy, and a preparation method therefor and the use thereof. Since the content of a binder-phase metal in the binder-phase-free hard alloy as provided is less than or equal to 1 wt%, WC crystal grains are difficult to grow into a plate-shaped morphology by means of dissolution-precipitation in the binder-phase metal, and the diffusion growth rate of each crystal plane and crystal boundary of the WC crystal grains is directionally controlled by adding elements such as boron, titanium, chromium and vanadium and controlling the amounts thereof; therefore, a portion of the crystal grains is controlled to grow into a polygonal lamellar morphology, crystal grains with a polygonal lamellar morphology are prepared under the conditions of substantially no binder-phase metal being present and flattening treatment not being required for raw material powder, the toughness of the binder-phase-free hard alloy is effectively improved, and the hardness is prevented from being significantly reduced to decrease the wear resistance.

The invention discloses a large-size low-grain-size 4N5 oxygen-free copper plate and a preparation method thereof, and the preparation method comprises the steps of first-fire forging, second-fire forging, third-fire forging and heat treatment to obtain the 4N5 oxygen-free copper plate. Through multiple times of upsetting and drawing in the forging process, crystal grains in metal are repeatedly crushed and recrystallized, the crystal grains are refined, then the heat treatment process is combined, the crystal grain size of the oxygen-free copper plate is further refined, large-size crystal grains are reduced, the structure uniformity of the oxygen-free copper plate is better, and the mechanical property of the oxygen-free copper plate is higher. After the low-grain-size 4N5 oxygen-free copper plate prepared through the method is precisely machined, due to the fact that the grain size of the low-grain-size 4N5 oxygen-free copper plate is small, grain growth is not obvious, residual stress is released in the heat treatment process, and then the problem that grains of a large-specification 4N5 oxygen-free copper plate grow abnormally in the high-temperature environment is solved.

The invention discloses a fine-grain tungsten-nickel-iron composite material and a low-temperature sintering preparation method thereof. The composite material takes W as a hard phase, Ni and Fe as binding phases, Y2O3 as a particle reinforcement phase and a grain growth inhibitor, and Sn as an alloy element and a sintering fluxing agent. The preparation method comprises the following steps: 1, carrying out carbon heat and hydrogen reduction on WO3, NiO, Fe2O3 and nano carbon black to obtain composite powder; 2, carrying out wet grinding with Sn and Y2O3 powder, and drying; 3, compression molding; 4, degreasing and pre-sintering treatment; and 5, low-temperature liquid-phase sintering. According to the composite material, low-temperature liquid-phase sintering is achieved by introducing the Sn element and the Y2O3, the wettability and the interface bonding force between W crystal grains and a bonding phase are improved, and the composite material with uniform components and refined crystal grains is obtained; the preparation method improves the tensile strength, microhardness and room temperature plasticity of the composite material, and is suitable for the fields of aerospace, national defense and military industry, nuclear industry, electronic information, metallurgy and the like.

The invention belongs to the field of hard alloy materials, and provides a modified high-performance non-magnetic hard alloy and a preparation process thereof. The surface of a WC particle is chemically plated with a Ni-P-B-Cr-Cu amorphous shell layer, and a binding phase is converted into Ni3P and Ni3B nanophase through two-stage sintering. The WC alloy comprises the following components in parts by weight: 85-95 parts of WC, 12-25 parts of a binding phase and 0.5-1.4 parts of a grain growth inhibitor, the nanophase accounts for 35-50% of the volume of the binding phase and 35-50% of the total volume of the binding phase, and the grain size is 80-125 nm; the average grain size of WC is 0.6-1.0 [mu] m; and the thickness of an interface P enrichment layer is 8-15 nm (the coverage rate is 85-95%). Through interface engineering and controlled crystallization from amorphous to nanocrystalline, the relative magnetic conductivity is 1.001-1.015, the hardness HRA is 90.5-93.0, the strength TRS is 2.2-3.0 GPa, the toughness KWP is 300-450 N / mm, and the magnetic saturation strength is 0.02-0.15 T. The problem of decoupling of the magnetic property and the mechanical property of a traditional non-magnetic hard alloy is solved, and the non-magnetic hard alloy is suitable for magnetic sensitive environments such as semiconductor equipment, precise measurement, MRI tools and oil service logging.

The invention relates to high-entropy carbonitride ceramic with controllable carbon nitrogen ratio, high hardness and high elastic modulus and a preparation method of the high-entropy carbonitride ceramic, and belongs to the technical field of high-entropy ceramics. In order to solve the problem that the existing preparation method is difficult to consider the regulation and control of the carbon nitrogen ratio and the mechanical property of the high-entropy carbonitride ceramic at the same time, the preparation method comprises the following steps: carrying out ball milling and drying on Ti powder, ZrH2 powder, Hf powder, Ta powder, Cr powder and carbon black to obtain mixed powder; performing heat treatment on the mixed powder in a nitrogen atmosphere to obtain ceramic powder; and carrying out spark plasma sintering on the ceramic powder to obtain the high-entropy carbonitride ceramic. The carbon vacancy concentration of a high-entropy system is regulated and controlled by adjusting the molar ratio of the metal powder to the carbon black, then introduction of nitrogen atoms is achieved, the carbon-nitrogen ratio of the ceramic powder is easier to regulate and control, grain growth can be effectively avoided through spark plasma sintering, the compact fine-grain high-entropy carbonitride ceramic can be obtained within a short time, and the high-entropy carbonitride ceramic has a good application prospect. The improvement of the mechanical property of the high-entropy carbonitride ceramic is facilitated.

The invention discloses a TiAlCrZrTa high-entropy alloy and a preparation method of the TiAlCrZrTa high-entropy alloy. The TiAlCrZrTa high-entropy alloy is composed of a matrix phase and dispersion particles, wherein the matrix phase is TiAlCrZrTa, and the dispersion particles comprise Ti-Ta-rich dendritic crystals, Ta-Cr-rich dendritic crystals and a Zr elementary substance; ti-Ta-rich dendritic crystals and Ta-Cr-rich dendritic crystals are dispersed and distributed in a matrix, dislocation movement is hindered, and the alloy strengthening effect is achieved; the Zr elementary substance is segregated at the grain boundary, pinning the grain boundary, inhibiting grain growth and being used for strengthening the alloy; the grain size of particles in the TiAlCrZrTa high-entropy alloy ranges from 5 micrometers to 10 micrometers. The problems that an existing high-entropy alloy preparation technology is complex, crystal grains are coarse and large, and components are not uniform are effectively solved.

The invention belongs to the field of photoelectric materials, and particularly relates to a vacuum vapor deposition perovskite material crystallization method, which is characterized in that vacuum vapor deposition of a perovskite precursor is carried out step by step, and a specific additive containing amide, amino, carboxyl and other functional groups is introduced in the deposition process to realize dynamic regulation and control of perovskite grain growth. According to the method, the perovskite crystallization kinetic process can be regulated and controlled, so that the crystallization of perovskite is optimized, the quality of the film is improved, the defects of the perovskite film are reduced, and the fluorescence quantum yield is improved.

The invention discloses a pyrochlore structure high-entropy ceramic solidified body material as well as a preparation method and application thereof, and belongs to the technical field of nuclear waste solidification. The preparation method of the high-entropy ceramic solidified body material with the pyrochlore structure comprises the following steps: weighing raw material powder of La2O3, Nd2O3, Sm2O3, Gd2O3, Eu2O3 and ZrO2 according to the proportion in (La0. 2Nd0. 2Sm0. 2Gd0. 2Eu0. 2) 2Zr2O7; the weighed raw material powder is subjected to ball milling treatment, and ball-milled powder is obtained; under the inert gas atmosphere, the ball-milled powder is subjected to heat treatment, and heat-treated powder is obtained; and carrying out spark plasma sintering on the heat treatment powder to obtain the pyrochlore structure high-entropy ceramic solidified body material. The powder is treated by using a heat treatment technology, so that the powder is homogenized, a pyrochlore phase is formed, grain growth is more favorably inhibited, a fine grain structure is obtained, and the irradiation stability and the mechanical property of the pyrochlore material are improved.

The invention provides a functional current collector, a pole piece using the same and a battery. The functional current collector comprises a base material and a first copper layer and a second copper layer which are sequentially arranged on at least one surface of the base material, the first copper layer is prepared through a magnetron sputtering process, the second copper layer is prepared through an electroplating process, and the X-ray diffraction peak intensity I (111) of the first copper layer on a crystal face (111) and the X-ray diffraction peak intensity I (200) of the first copper layer on a crystal face (200) meet the condition that I (111) / I (200) is larger than or equal to 6 and smaller than or equal to 8. The first copper layer of the functional current collector provided by the invention satisfies 6 < = I (111) / I (200) < = 8, so that the defects of dislocation, interface and the like during molding caused by grain growth and thermal deformation when the second copper layer is compounded on the surface of the first copper layer can be improved, the defects of the second copper layer are reduced, the compactness is higher, the resistivity of the functional current collector is reduced, and the service life of the functional current collector is prolonged. And the energy density, the cycle life and the safety performance of the battery using the material are improved.

Disclosed are a MAX-Ag conductive composite coating and a preparation method therefor. The conductive composite coating comprises a MAX phase and an Ag phase. The chemical formula of the MAX phase is Mn+1AXn, where M is a transition metal element, A is an Al element, X is a C or N element, and n is an integer ranging from 1 to 3. The MAX phase is of a strip-shaped structure, and the Ag phase is of a nanotwinned structure. The Ag phase aggregates at the grain boundaries of the MAX phase, and the conductive composite coating is of an Ag-wrapped MAX phase structure as a whole. In the present invention, the MAX phase coating is designed, by means of Ag doping, to have a heterogeneous grain shape. The doped Ag affects the growth of MAX phase grains, so that the MAX phase grains are of the strip-shaped structure. Furthermore, the doped Ag is of the nanotwinned structure, and fully wraps the MAX phase grains. Ag is continuously distributed at the MAX grain boundaries. Such a special structure may effectively reduce the scattering of electrons, provide a strong conductive path, and enable the coating to have excellent conductive properties.

The invention discloses a heat treatment method for improving the structure uniformity of an additive-state GH4169 alloy, and belongs to the technical field of heat treatment processes. The method comprises the following steps: carrying out pre-aging treatment on the additive-state GH4169 alloy, and carrying out air cooling to room temperature; then carrying out homogenization treatment, and carrying out water cooling to room temperature; and finally, two-stage aging treatment is conducted, and air cooling is conducted to the room temperature. According to the method, the delta phase is precipitated at the grain boundary in a saturated mode through pre-aging treatment, and grain growth in the follow-up homogenization process is effectively limited through pinning of the grain boundary; the precipitation uniformity of a gamma'phase and a gamma ''phase in subsequent two-stage aging treatment is improved through homogenization treatment, recrystallization can be promoted, the grain structure can be transformed, the texture strength can be reduced, the grain structure uniformity can be improved, and the mechanical property of the additive-state GH4169 alloy can be improved; two-stage aging treatment is adopted, so that a gamma'phase and a gamma ''phase which are uniformly distributed are separated out from the additive-state GH4169 alloy, the effect of aging strengthening is achieved, and the yield strength, the tensile strength, the ductility and other mechanical properties of the additive-state GH4169 alloy are improved.

The invention discloses a method for improving the thermal stability of a gradient nanocrystalline structure, and belongs to the technical field of metal material processing. According to the method, Mg-RE series alloy is used as a matrix, a matrix alloy ingot is heated for solution treatment, surface strengthening is carried out after water quenching and cooling, a gradient nanocrystalline layer is formed on the surface layer of an alloy sample, finally, the alloy sample is transferred into an aging oven for low-temperature aging, and cooling is carried out, so that the magnesium alloy is obtained. According to the method, the thermal stability of the magnesium alloy gradient nanocrystalline is improved through a synergistic strategy of component design and low-temperature aging, so that the grain growth rate of Mg-RE alloy gradient nanocrystalline structures treated by various different surface strengthening methods in a high-temperature environment can be remarkably reduced; the core bottleneck that a traditional magnesium alloy gradient nanocrystalline material is poor in thermal stability and single in applicable surface treatment method is solved; and the process does not need special equipment, can be seamlessly connected with various existing magnesium alloy surface strengthening production lines, and is low in process cost, simple and convenient to operate and easy to industrially popularize.

The present invention discloses a twinned and dispersion-strengthened WC-Ni-based cemented carbide and its preparation method. The alloy is composed of a hard phase component WC, a bonding metal Ni, and supersaturated composite grain growth inhibitors Cr3C2 and VC. The WC hard phase in the alloy is composed of irregular grains with an average grain size of less than 0.5 μm and dispersed small plate-like grains. The typical morphological characteristics of the fine plate-like WC grains in the polished cross-section of the alloy are long strips with an average length of less than 2.2 μm and an average width of less than 0.5 μm. Nano-dispersed phases exist in the Ni-based bonding phase solid solution matrix in the alloy. The present invention uses unsaturated carbon nano-WC powder as raw material, and through ultrafine grain strengthening of the hard phase, strengthening of dispersed fine plate-like crystals, and nano-dispersed phase strengthening of the bonding phase, the alloy is given high hardness, high toughness, and high strength.

The application discloses a preparation of a low-temperature and low-bombardment transparent conductive film and application of the transparent conductive film in a perovskite / crystalline silicon laminated solar cell. The composite film is prepared by magnetron sputtering of TCO ceramic targets with different doping ratios at room temperature. ‑5 The composite transparent conductive oxide film is obtained by adjusting the sputtering pressure and power of the TCO film with different doping ratios and adjusting different growth modes, and the composite transparent conductive oxide film has a low-temperature and low-bombardment property. The lower layer of the composite transparent conductive oxide film is in a columnar crystal growth mode, and the upper layer is in an equiaxed large-grain growth mode. The composite transparent conductive oxide film can be applied in a perovskite / silicon laminated solar cell, can promote the vertical and horizontal transmission capacity of carriers in a TCO transparent electrode, promotes the effective collection and transmission of carrier charges, and thus a high-efficiency perovskite / silicon laminated solar cell is obtained.

The invention belongs to the technical field of ceramic preparation, and particularly relates to a tin oxide ceramic material and a preparation method and application thereof. According to the invention, oxygen vacancies are introduced into the conductive doped oxide, so that the conductivity of tin oxide is greatly improved; the sintering aid promotes liquid-phase sintering of the biscuit in the sintering process, so that the problem of sintering difficulty caused by volatilization of tin oxide at a high temperature of 1200 DEG C is solved, particle rearrangement and mass transfer processes are greatly promoted, and sintering densification of tin oxide is promoted; due to the introduction of gallium oxide, not only is pinning at the tin oxide grain boundary to prevent grain growth and obtain uniform and fine grain size, but also the conductivity of the ceramic material is further improved. The tin oxide ceramic material obtained by the invention has the characteristics of high density, low resistivity and uniform and fine crystal grains. Meanwhile, the preparation process is simple and suitable for industrial production.

The invention belongs to the technical field of refractory materials, and particularly relates to a mullite refractory material with high mechanical property and a preparation method thereof. The mullite refractory material is prepared by taking coal gangue, bauxite and fly ash as raw materials, and the three industrial solid wastes are converted into the refractory material with high additional value, so that the concept of circular economy is met. According to the invention, coal gangue, bauxite and fly ash are used as raw materials, CaF2, V2O5 and lanthanide rare earth oxide are used as sintering aids, the problems of insufficient mechanical properties and overhigh sintering temperature of the mullite refractory material prepared by purely using coal gangue, bauxite and fly ash as raw materials are solved, and the performance of the mullite refractory material can be greatly improved. CaF2 and V2O5 promote substance transport and grain growth, and rare earth oxide inhibits excessive growth of grains. The balance of'promotion 'and'inhibition' is favorable for forming a compact, fine, uniform and interlaced mullite crystal network, and meanwhile, the mullite crystal network has high strength and good toughness.

The invention discloses a high-temperature high-strength zirconium alloy and a manufacturing method thereof and belongs to the field of nuclear engineering materials. The high-temperature and high-strength zirconium alloy comprises the following components in percentage by weight: 1%-10% of Sn, 0.1%-1% of O, 0.01%-3.5% of Al, 0.01%-0.5% of Si and / or 0.01%-0.5% of Ge, and the balance of Zr and inevitable impurities. In the high-temperature and high-strength zirconium alloy, Si and / or Ge can form a precipitated phase which is thermodynamically stable at a high temperature, an alpha-Zr grain boundary is pinned at the high temperature while grain refinement is promoted, solid-state phase change and grain growth in a zirconium alloy matrix at the high temperature are inhibited, and the alloy keeps good mechanical property and structure stability at the high temperature.

The invention relates to the field of high-temperature refractory materials, and discloses a fusion casting method for improving the performance of an AZS octagonal cylinder checker brick, which comprises the following steps: mixing and smelting main raw materials and a composite additive (containing surface-modified nano YAG particles and a rare earth core-shell structure) to obtain a high-purity melt in an inert atmosphere; staged vibration pouring is conducted in the vacuum environment, low-frequency vibration and high-frequency vibration are combined, and the melt filling compactness is improved; an alternating magnetic field is coupled in the gradient cooling process, grain growth is directionally regulated and controlled, and thermal stress is released; and annealing treatment is combined with a surface densified coating, so that the defects are further eliminated, and the erosion resistance is enhanced. According to the invention, through linkage of technologies such as strengthening of a crystal boundary by the composite additive, collaborative optimization of a structure by vibration-magnetic field, inhibition of phase change by a gradient process and the like, the material has excellent thermal shock resistance, high-temperature strength and molten medium corrosion resistance, and is suitable for harsh working conditions such as glass kilns and metallurgical high-temperature equipment.

According to the preparation method of the free-cutting lead brass alloy, trace elements such as tellurium, cobalt, samarium and selenium are added into lead brass, the tellurium, the selenium and the like can easily form low-melting-point compounds with other elements, grain growth can be inhibited, dispersed distribution of fine lead particles is promoted, stress concentration is reduced, and the cutting performance is improved; by adding cobalt, samarium and the like, grain refinement is facilitated, distribution and forms of selenium, tellurium and other elements are changed, alloy fluidity is promoted, dispersed distribution of lead and the like is promoted to be more uniform, the cutting performance is further improved, in addition, dissolution of lead can be inhibited through the passive film layer, the environment-friendly performance is improved, and harm caused by dissolution of lead is reduced.

The invention discloses a high-performance wear-resistant steel ball production process based on powder metallurgy, and aims at solving the problems that a traditional cast steel ball is poor in wear resistance, the powder metallurgy process is low in efficiency and the like, breakthrough is achieved through multi-phase collaborative design and electric field activated sintering, medium-carbon low-alloy steel is used as a matrix, nano TiC (dispersion strengthening) and h-BN (self-lubricating) are compounded, and the high-performance wear-resistant steel ball production process based on powder metallurgy is obtained; a gradient structure (high Cr / high TiC on the surface layer strengthens wear resistance, and low Cr / low TiC on the core part ensures toughness) is constructed; the electric field activated sintering technology is adopted for low-temperature rapid densification (the density is larger than or equal to 99.2%), and grain growth is remarkably inhibited. The technology breaks through the hardness-toughness contradiction, is suitable for high-impact and high-wear extreme working conditions, and provides a low-cost solution for localization of high-performance wear-resistant materials.