1116results about "Nitrogen compounds" patented technology

The invention relates to the technical field of composite film preparation, in particular to a multi-layer co-extrusion nano ceramic coating high-barrier medicine packaging composite film and a preparation method thereof.The multi-layer co-extrusion nano ceramic coating high-barrier medicine packaging composite film comprises a base material layer, a gas barrier layer, a bonding transition layer and a nano ceramic functional coating; the base material layer comprises the following components in parts by mass: 80-100 parts of biaxially oriented polypropylene; 20 to 30 parts of metallocene linear low density polyethylene; 5 to 8 parts of nano titanium dioxide; 0.5 to 1 part of beta-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid; and 0.3 to 0.6 part of calcium stearate. Through the multi-layer co-extrusion and gradient curing technology and the five-layer co-extrusion technology, it is ensured that the thickness of a base film is uniform and interlayer bonding is firm, the adhesive force of the coating is enhanced through plasma surface treatment, and activity retention and uniform distribution of functional components are guaranteed through the segmented curing strategy of the nano ceramic coating; compared with a traditional hot-pressing compounding or solvent coating process of the composite film, the energy consumption and the solvent residue risk are greatly reduced, meanwhile, the production efficiency and the product consistency are improved, and large-scale application is provided for medicine packaging.

The invention relates to the field of aluminum materials, and provides an automobile corrosion-resistant aluminum material and a preparation method thereof.The automobile corrosion-resistant aluminum material is prepared from cerium oxide loaded aluminum oxide nanorods, scandium / boron nitride nanotubes, zirconium powder, magnesium powder, copper powder, manganese powder, silicon carbide nanoparticles, TiB2 nanoparticles, aluminum powder and stearic acid. Wherein the cerium oxide loaded aluminum oxide nanorod is composed of an aluminum oxide nanorod and cerium oxide nanoparticles loaded on the surface of the aluminum oxide nanorod, and the scandium / boron nitride nanotube is composed of a boron nitride nanotube and a scandium nanolayer uniformly coated on the surface of the boron nitride nanotube. The material is prepared through mechanical ball milling, cold isostatic pressing forming, vacuum sintering and aging treatment, and finally the aluminum-based composite material containing the Al3Sc nano precipitated phase and the boron nitride nanotube reinforced phase is formed. And an Al3Sc precipitated phase and an aluminum matrix form a coherent interface, so that the strength, the corrosion resistance and the wear resistance of the material are improved. Through nanostructure optimization, high performance of the aluminum alloy is achieved, and the aluminum alloy is suitable for the fields of automobiles, aerospace and the like.

The invention belongs to the technical field of biomedical engineering, and particularly relates to a single-base resolution laminated two-dimensional material nanopore structure, a DNA sequencing device and a DNA sequencing method. The two-dimensional material nanopore structure comprises an insulating layer and conducting layers arranged on the upper side and the lower side of the insulating layer, through nanopores are formed in the insulating layer and the conducting layers, and the pore diameter of the nanopores is 2-5 nm; the insulating layer and the conductive layer are made of two-dimensional materials. The conductive layers on the two sides serve as upper and lower electrodes, and a power supply is connected between the upper and lower electrodes to form a phase conductive path which is provided with a longitudinal current detection element. A plurality of groups of two-dimensional material nanopore structures are stacked, and meanwhile, a plurality of groups of base pair signals are obtained. According to the invention, the advantages of small thickness, high physical strength and the like of the two-dimensional material nanopore are kept by using a few layers of two-dimensional material films, the vibration of the films is reduced by increasing the number of layers and improving the mechanical strength, so that the signal-to-noise ratio is improved, and the spatial resolution of the nanopore sensor is improved by designing the upper electrode and the lower electrode.

Improved electrocatalysts for promoting a hydrogen evolution reaction (HER) or an oxygen evolution reaction (OER) from alkaline fresh water and seawater are disclosed. By incorporating metals, such as tungsten and rare earth elements, into the nickel molybdenum nitride framework, Ni1-xMoxN, the disclosed electrocatalysts demonstrate improved catalytic activity and stability compared to the original Ni&Ni0.2Mo0.8N catalysts, particularly under high-current alkaline conditions, in water electrolysis for hydrogen and oxygen production.

A phosphor plate includes a plate-like composite including a base material and a phosphor contained in the base material, in which the base material contains spinel, the phosphor includes a phosphor containing a Si element, and in an X-ray diffraction pattern of the phosphor plate using a Cu-Kα ray, in a case in which peak intensity corresponding to the spinel having a diffraction angle 2θ in a range of 36.0° or more and 37.4° or less is set to 1, total intensity of peaks having a diffraction angle 2θ in a range of 32.5° or more and 34.5° or less satisfies 0.5 or less.

The invention relates to the technical field of wear-resistant materials, in particular to a nano wear-resistant composite material and a preparation method and application thereof, and the nano wear-resistant composite material comprises the following raw materials in parts by weight: 45-50 parts of nano tungsten carbide, 10-15 parts of cobalt powder, 7-11 parts of a modified nano titanium nitride agent, 5-7 parts of nano neodymium oxide, and 4-6 parts of a nano TaC-doped complexing agent. According to the nano wear-resistant composite material, the nano tungsten carbide is matched with the cobalt powder and the nano neodymium oxide, the modified nano titanium nitride agent, the doped nano TaC and the synergist are coordinated and matched, and the raw materials are coordinated and synergistic, so that the wear resistance, the yield strength performance and the fatigue resistance of the obtained nano wear-resistant composite material are coordinated and improved; meanwhile, the product is excellent in performance stability under different degrees of salt corrosion conditions.

The invention provides a silicon-carbon negative electrode material and a preparation method thereof, and particularly relates to the technical field of lithium battery negative electrode materials. The silicon-carbon negative electrode material comprises coating porous carbon, coating silicon deposited in channels of the coating porous carbon and an amorphous carbon layer coating the outer layer of the coating porous carbon, the coating porous carbon comprises porous carbon and a first silicon nitride coating; the first silicon nitride coating coats the interiors of pore channels of the porous carbon and the outer surface of the porous carbon; and the coating silicon comprises silicon and a second silicon nitride coating coated on the surface of the silicon. In the silicon-carbon negative electrode material provided by the invention, the porous carbon is protected through the first silicon nitride coating, side reaction is reduced, charge and discharge stress is buffered, and structural damage is prevented. The second silicon nitride coating relieves the stress of the silicon material and protects the structural integrity. The layered silicon nitride enhances the electrochemical performance, and the amorphous carbon layer reduces the side reaction, thereby improving the efficiency and service life of the battery, and ensuring the double improvement of the battery performance and structural stability.

The invention provides silicon nitride and aluminum nitride powder and a preparation method, and relates to the technical field of ceramic powder. The preparation method of the silicon nitride and aluminum nitride powder comprises the following steps: mixing aluminum powder and aluminum nitride raw powder to obtain a first mixture; mixing silicon powder, silicon nitride raw powder and ammonium salt to obtain a second mixture; paving the first mixture and the second mixture in a material frame padded with a carbon felt, and separating the first mixture from the second mixture by using the carbon felt; the material frame is placed in a self-propagating reaction kettle, nitrogen is introduced after vacuumizing, and the first mixture is ignited so as to induce a combustion synthesis reaction of the second mixture; and after the combustion synthesis reaction, cooling to room temperature, releasing the pressure in the self-propagating reaction kettle, taking out a synthetic product, and grinding the synthetic product to obtain silicon nitride powder and aluminum nitride powder. The purity of the powder material can be improved.

Flash Joule heating (FJH) for production of one-dimensional (1D) carbon and / or boron nitride nanomaterials, and 1D materials integrated with 0D, 1D, 2D, and 3D nanomaterials, composites, nanostructures, networks, and mixtures thereof. Such materials produced by FJH include 1D carbon and hybrid nanomaterials, boron nitride nanotubes (BNNTs), turbostratic boron-carbon-nitrogen (BCN), doped (substituted) graphene, and heteroatom doped (substituted) re-flashed graphene.

An exemplary embodiment of the present disclosure provides a method for making an electrolyte, comprising: providing a solid polymer electrolyte (SPE); incorporating boron nitride with the SPE to form a composite polymer electrolyte (CPE), wherein the boron nitride is at least one of exfoliated hexagonal boron nitride (ex-BN) or fluorine-fimctionalized hexagonal boron nitride (BN-F).

The invention provides a preparation method of a molybdenum phosphide / titanium nitride composite material and a battery positive electrode material and a lithium-carbon dioxide battery, and belongs to the technical field of new energy materials. And then a titanium nitride conductor layer is deposited on the molybdenum phosphide by using an atomic layer deposition technology to prepare the molybdenum phosphide / titanium nitride, the molybdenum phosphide is combined as a transition metal phosphide to have stable catalytic performance, and the titanium nitride is used as a conductor to have excellent conductivity. The lithium-carbon dioxide battery positive electrode catalyst with high catalytic activity, high conductivity and excellent stability is obtained through the synergistic effect of the two materials, and when the lithium-carbon dioxide battery positive electrode catalyst is applied to a lithium battery, higher energy density, longer cycle life and better rate capability are shown, so that the overall performance of the battery is improved, and the application prospect is wide. The requirements on high-performance batteries in the fields of electric automobiles, energy storage systems and the like are met.

The invention relates to the technical field of ceramic materials, and discloses a preparation process for producing hexagonal boron nitride by a low-temperature method, which comprises the following specific steps: mixing borax and urea according to a certain mass ratio, and adding into a ball mill for ball milling to obtain a material A with uniform particle size; adding a modified material with a proper mass ratio into the material A, and continuing ball milling to uniformly disperse the modified material to obtain a material B; transferring the material B into a tubular furnace into which high-purity ammonia gas is introduced, heating to about 900 DEG C at a proper rate, and preserving heat for several hours to complete the reaction; and after the reaction is completed, cooling along with the furnace, washing the product with deionized water until the product is neutral, sieving with a 300-mesh sieve, and carrying out vacuum drying at 70-90 DEG C for a certain time to finally prepare the high-crystallinity hexagonal boron nitride. According to the process, boron-nitrogen reaction kinetics is promoted through the modified material, generation of cubic boron nitride impure phases is inhibited, compared with a traditional high-temperature method, energy consumption is remarkably reduced, product purity and crystallinity are improved, and the process is suitable for large-scale production.

Provided is a magnetic powder having good high-frequency characteristics with low iron loss and good efficiency even at high frequencies. The present disclosure relates to an α-Fe-containing rare earth-iron-nitrogen-based magnetic powder, including: a core region containing a rare earth R, Fe, and N, where R represents at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when R contains Sm, Sm constitutes less than 50 atm% of a total R content; and an α-Fe-containing region outside the core region, the α-Fe-containing region containing α-Fe and at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R.

Provided are solid-state hybrid electrolytes. The hybrid electrolytes have a polymeric material layer, which may be a polymer copolymer layer or a gel polymer copolymer layer, disposed on at least a portion of an exterior surface or all of the exterior surfaces of a solid-state electrolyte. A hybrid electrolyte can form an interface with an electrode of an ion-conducting battery that exhibits desirable properties. The solid-state electrolyte can comprise a monolithic SSE body, a mesoporous SSE body, or an inorganic SSE having fibers et strands, which may be aligned. In the case of solid-state electrolytes that have strands, the strands can be formed using a sacrificial template. The hybrid solid-state electrolytes can be used in ion-conducting batteries, which may be flexible, ion-conducting batteries.

To provide silicon-containing aluminum nitride particles, a sintered body, a resin composition, and a method for producing silicon-containing aluminum nitride particles.SOLUTION: Provided are silicon-containing aluminum nitride particles, wherein, when the total of a mass of aluminum and a mass of silicon analyzed from the particles by an inductively coupled plasma optical emission spectrometer and a mass of oxygen and a mass of nitrogen analyzed from the particles by an oxygen-nitrogen analyzer is set to 100 mass%, a total mass ratio of the aluminum and the nitrogen is 90 mass% or more, a mass ratio of the silicon is within a range of 1.5 mass% or more and 10.0 mass% or less, a mass ratio of the oxygen is X mass%, a specific surface area of the particles measured by a BET method is Y 2 / g, and a ratio (X / Y) is within a range of 0.40 or more and 0.85 or less.SELECTED DRAWING: Figure 2

The invention relates to a multi-airflow alternating temperature calcining device for ultra-long nitride single crystal nanofibers. The multi-airflow alternating temperature calcining device comprises a reaction furnace; the mechanical vacuum pressure gauge and the exhaust port are arranged at the top of the reaction furnace; the reaction furnace chamber is arranged in the reaction furnace; the multi-reaction-zone graphite furnace body is arranged in the reaction furnace chamber and comprises a first low-temperature zone, a second high-temperature zone and a third low-temperature zone which are sequentially arranged from bottom to top and are not in contact with one another; the electromagnetic heating controller is arranged on the periphery of the multi-reaction-area graphite furnace body; the graphite boat is movably arranged in the multi-reaction-area graphite furnace body; the movable alumina crucible is arranged in the graphite boat; the graphite columns are arranged at the top and the bottom of the multi-reaction-zone graphite furnace body; the hydraulic cylinder is connected with the graphite column; and a control assembly. Compared with the prior art, the method has the advantages that the nitridation reaction process can be accurately controlled, the fiber quality and the crystal integrity can be improved, and independent and accurate temperature control can be realized.

The invention discloses a preparation method and application of an ultrathin large-size hexagonal boron nitride nanosheet capable of being produced on a large scale, and belongs to the technical field of two-dimensional material preparation. The method comprises the following steps: 1, preparing a boron nitride dispersion solution; 2, performing ultrasonic oscillation on the boron nitride dispersion liquid by using an ultrasonic processor; 3, stirring the boron nitride dispersion liquid subjected to ultrasonic pretreatment at an ultra-high speed by using a wall breaking machine; and 4, centrifuging the stirred boron nitride, taking supernate, washing and drying to obtain the ultrathin large-size boron nitride nanosheet. The preparation method disclosed by the invention has the characteristics of simplicity, high efficiency, economy, environmental protection, high yield, high reliability, large-scale preparation and the like, and the prepared boron nitride nanosheet has the advantages of large sheet diameter, small thickness, uniform particles, high lattice integrity and the like, and can be applied to the fields of thermal management, energy storage and photoelectrochemistry of electronic devices.

The invention relates to the field of inorganic powder preparation, and particularly discloses a preparation method and application of aluminum nitride powder. The preparation method of the aluminum nitride powder comprises the following steps: (1) by taking water as a dispersion medium, dispersing hydroxyl aluminum oxide and a carbohydrate into the dispersion medium, and then carrying out hydrothermal reaction to obtain a precursor; the precursor has a carbon-coated hydroxyl alumina core-shell structure; (2) calcining the precursor in a nitrogen-containing atmosphere to obtain aluminum nitride powder; wherein the volume equivalent diameter of the aluminum hydroxide is less than 0.82 mu m. By implementing the method, the aluminum nitride powder with high purity and excellent particle size distribution can be obtained.

The invention relates to a preparation method of silicon dioxide-boron nitride nanobelt aerogel, which comprises the following steps: dissolving melamine and boric acid in a co-solvent of tert-butyl alcohol and hot deionized water, stirring and mixing, carrying out ultrasonic treatment, freeze-drying and the like to obtain a melamine-boric acid aerogel precursor, placing the precursor in a tubular furnace, and carrying out vacuum drying to obtain the silicon dioxide-boron nitride nanobelt aerogel. Pyrolyzing in an ammonia gas atmosphere to obtain boron nitride nanobelt aerogel; and placing the boron nitride nanobelt aerogel in a xylene solution containing tetraethoxysilane and silicon tetrachloride, taking out the boron nitride nanobelt aerogel, and drying the boron nitride nanobelt aerogel. And hydrolyzing and pyrolyzing in an inert atmosphere to form a silicon dioxide layer on the surface, thereby obtaining the silicon dioxide-boron nitride nanobelt aerogel. The silicon dioxide and boron nitride nanobelt aerogel is low in density and excellent in mechanical property and oxidation resistance.

The invention relates to the technical field of neutron imaging, and discloses a gamma ray inhibition neutron imaging system based on a boron nitride scintillation screen and application thereof.The neutron imaging system comprises the boron nitride scintillation screen, a light path system and a camera, the boron nitride scintillation screen is located in front of the light path system and installed at the position of a neutron incidence window, and the camera is located in front of the light path system; the light path system is connected with the camera, the light path system is provided with different light path units according to the high-flux neutron beam source, the low-flux neutron beam source and long-distance neutron imaging, and the camera is used for receiving the scintillation light processed by the light path system and recording photon information. According to the neutron imaging system, background signals caused by gamma rays can be reduced, so that the signal-to-noise ratio is improved, obtained images are clearer, noise and artifacts are reduced, the imaging quality and detection accuracy of the images are improved, and the neutron imaging system has important application potential in the fields of high-energy physical experiments and industrial detection.

The invention relates to the technical field of preparation of boron nitride materials, in particular to a high-yield preparation method of an amination modified boron nitride nanosheet, which comprises the following steps: S1, mixing boron nitride and 2, 2-bis (trifluoromethyl) diaminobiphenyl in a tank, and adding ball milling beads; s2, inert gas is injected into the tank, sealing treatment is carried out, and dry ball milling treatment is carried out; and S3, dispersing the mixture subjected to ball milling treatment by using an alcohol solvent, centrifuging, filtering and drying to obtain the amination modified boron nitride nanosheet. According to the preparation method disclosed by the invention, 2, 2-bis (trifluoromethyl) diaminobiphenyl is taken as a modification reagent, and dry ball milling is carried out under an inert condition, so that the yield of the obtained amination modified boron nitride nanosheet is up to 67.2-79.2 wt%, and the highest yield can be up to 86.7 wt%; the saturation dispersion degree of the amination modified boron nitride nanosheet in a DMAc dispersion liquid is as high as 5 mg / mL.

The invention discloses a renewable energy-driven nitrogen-carbon-hydrogen coupling fixation nitrogen fertilizer preparation device and method. On-site conversion of renewable energy and zero-carbon synthesis of nitrogen fertilizers (ammonia, ammonium nitrate, ammonium bicarbonate, urea and the like) can be realized under the condition that additional energy and material input are not needed. Energy management and system energy supply are achieved by means of renewable energy source driving and a flexible control technology, and materials such as carbon dioxide, nitrogen and water are continuously obtained from the environment based on a direct air trapping technology; the green nitrogen fertilizer is synthesized by direct selective catalytic conversion of inert nitrogen, oxygen, hydrogen and other materials by using a low-temperature plasma-electro-catalysis composite conversion system and equipment. According to the invention, stable and efficient synthesis of air into the nitrogen fertilizer with high added value is realized under the driving of renewable energy sources, so that instant green fertilizer and chemical supply is provided for remote areas such as high mountains, deserts and islands and areas lacking industrial foundations, and the method has a good application prospect.

The invention relates to the technical field of aerogel materials, in particular to a Si3N4 nanofiber aerogel material and a preparation method thereof. The aerogel material is formed by stacking and assembling multiple layers of Si3N4 nanofiber films, the upper surface of each Si3N4 nanofiber film is of a high-density network structure formed by interweaving Si3N4 nanofibers, and the lower surface of each Si3N4 nanofiber film is of a pearl necklace-shaped structure formed by interweaving Si3N4 nanofibers and Si3N4 nanoparticles. The preparation method disclosed by the invention provides a new thought for developing the structure-enhanced nanofiber aerogel, and the Si3N4 nanofiber aerogel material prepared by the method disclosed by the invention is expected to meet the development requirements of a wave-transparent antenna housing of an ultra-high-speed aircraft on a high-temperature-resistant / heat-insulating / wave-transparent integrated material.

The invention provides a pulse-direct current electrochemistry composite deposition process of a nickel-tungsten-phosphorus alloy coating, and belongs to the technical field of coating preparation, and the pulse-direct current electrochemistry composite deposition process comprises the following steps: carrying out silane coupling agent modification treatment on alpha-aluminum oxide; carrying out modification treatment on the hexagonal boron nitride nanosheet by adopting hexadecyl trimethyl ammonium bromide; carrying out polyacrylic acid modification treatment on the nano silicon dioxide; nickel salt, tungsten salt, phosphorus salt, a complexing agent, a buffering agent, a primary brightener, a secondary brightener, a wetting agent, modified aluminum oxide, modified boron nitride, modified silicon dioxide and deionized water are mixed, stirred and heated, and a composite plating solution is obtained; the substrate serves as a cathode, pulse current is applied to the substrate for pulse electroplating, then the current density of the pulse current is continuously and linearly reduced to a target value, and finally direct current electroplating is conducted under the target value; by optimizing the formula of the composite plating solution and the pulse-direct current composite electroplating process, the nickel-tungsten-phosphorus alloy composite plating layer with high hardness, low friction, high wear resistance and corrosion resistance is finally obtained.

An aluminum nitride powder according to the present invention has an average particle size of 5 to 50 µm and an oxygen content of 0.5 % by mass or less, has polyhedral particles having at least two smooth surfaces 'a' under observation with a scanning electron microscope at 500x magnification, in which for the polyhedral particles with a major axis (L) of 5 µm or more, the average value of the ratio (L / D) of the major axis (L) to the minor axis (D) is within the range of 1 to 1.4. According to the present invention, an aluminum nitride powder having high thermal conductivity when filled in a resin to obtain a resin composition, and good fluidity, can be provided.

The present invention relates to a hexagonal boron nitride nanosheet and a preparation method thereof, the preparation method comprising the following steps: S1, ball-milling a boron-containing compound and a nitrogen-containing compound, mixing them uniformly, heating them in a protective atmosphere, and preparing a precursor; S2, ball-milling the precursor obtained in step S1 and a molten salt, mixing them uniformly, calcining them at high temperature in a protective atmosphere, washing, filtering, and drying them after cooling to room temperature, and obtaining hexagonal boron nitride nanosheets. Compared with the prior art, the present invention can obtain nano-scale hexagonal boron nitride at a relatively low temperature of 1200°C, and the heating process has lower energy consumption and is more cost-saving.

The invention relates to the field of inorganic nonmetal powder materials, and discloses a preparation method of silicon nitride powder, which comprises the following steps: (1) mixing a surfactant, liquid ammonia and an organic solvent to form a to-be-reacted solution, and mixing the to-be-reacted solution with a silicon tetrachloride solution for substitution reaction to obtain a solution containing silicon imine suspended matters; the surfactant is selected from one or more of sodium dodecyl sulfate, polyvinylpyrrolidone, sodium stearate, sodium dodecyl benzene sulfonate, fatty acid methyl ester ethoxylate sulfonate, fatty acid sorbitan, polysorbate-20 and polysorbate-80; the surfactant is selected from one or more of sodium dodecyl sulfate, polyvinylpyrrolidone, sodium stearate, sodium dodecyl benzene sulfonate, fatty acid methyl ester ethoxylate sulfonate, fatty acid sorbitan, polysorbate-20 and polysorbate-80; (2) carrying out suspended matter extraction and impurity removal on the solution containing the silicon imine suspended matter to obtain silicon imine powder; (3) performing thermal decomposition on the silicon imine powder to obtain amorphous silicon nitride powder; and (4) crystallizing the amorphous silicon nitride powder to obtain the alpha-phase silicon nitride powder. The method can reduce the impurity content and agglomeration degree of the precursor so as to improve the quality of the silicon nitride powder.

To provide a method for producing hexagonal boron nitride powder in which a hexagonal boron nitride powder is effectively reacted with a surface treatment agent.SOLUTION: The method for producing modified hexagonal boron nitride powder of the present invention includes a heating step of heating hexagonal boron nitride powder at a temperature of 1300°C or higher and 2200°C or lower in a nitrogen atmosphere, and a first surface treatment step of contacting the re-calcination hexagonal boron nitride powder after the heating step with a first surface treatment agent. From the heating step to the first surface treatment step is performed under an environment of re-calcination hexagonal boron nitride powder at an absolute humidity of 15 g / m3 or less.SELECTED DRAWING: None

The invention provides a preparation method and a low-temperature spray freeze-drying dispersion method of ultra-long BNNT, a boron source, metal nitrate and nano metal oxide are uniformly mixed, mixed gas is introduced, heating annealing is performed to prepare the ultra-long BNNT, the diameter of the prepared ultra-long BNNT is 50-150 nm, the tube length of the BNNT is 100-500 [mu] m, and the wall thickness of the BNNT is 10-30 nm; the mixed gas is nitrogen and ethanol. The agglomeration effect of the nanotube powder is not obvious, the freeze-drying efficiency of the nanotube powder is greatly improved, and the homogeneous dispersion process of the prepared BNNT is simple in process, high in efficiency and good in uniformity and has great industrialization advantages.

The invention provides a method for synthesizing low-oxygen high-alpha-phase silicon nitride powder through direct nitridation of silicon sawdust, and belongs to the technical field of silicon nitride preparation. The method comprises the following steps: carrying out acid pickling, impurity removal and purification treatment on silicon sawdust to obtain a silicon raw material of which the main metal impurities are less than 10ppm and the oxygen content is less than 2%; the silicon raw material and a regulator are mixed according to a preset proportion and subjected to ball milling treatment, a mixed material is obtained, and the regulator comprises sodium chloride and carbon powder; introducing a gaseous nitrogen source, and carrying out vacuum gradient heating nitridation treatment on the mixed material to obtain a silicon nitride crude product; and sequentially carrying out acid pickling, solid-liquid separation, cleaning and drying post-treatment on the silicon nitride crude product to obtain the low-oxygen high-alpha-phase silicon nitride powder. According to the invention, the silicon sawdust is subjected to pickling purification, and the obtained silicon sawdust is directly nitrided at low temperature under the assistance of sodium chloride and carbon powder to synthesize alpha-phase silicon nitride; and then the high-dispersion and high-purity alpha-phase silicon nitride powder can be obtained through an acid pickling-water washing-drying process. The silicon nitride product prepared by the method can be used as a raw material of silicon nitride ceramic.