22 results about "Magnesium nitride" patented technology

The invention relates to magnesium silicon nitride powder as well as a preparation method and application thereof, and belongs to the technical field of structural ceramic powder materials. The preparation method comprises the following steps: pinning silicon nitride powder into magnesium powder to form magnesium-based composite powder with a micro-nano composite structure on the surface; mixing the magnesium-based composite powder with a dispersing agent to obtain a reaction precursor; carrying out self-propagating synthesis reaction on the reaction precursor to obtain silicon magnesium nitride composite powder; and sequentially carrying out acid pickling treatment and calcination treatment on the silicon magnesium nitride composite powder to obtain the silicon magnesium nitride powder. The yield of the prepared magnesium silicon nitride is 95% or above, the oxygen content of the product is lower than 0.15 wt.%, and the particle size is controlled to be 1-2 microns and is uniformly distributed; the method is suitable for application of sintering aids of high-performance ceramics, refractory material components and reinforcement phases of metal-based composite materials.

The application discloses a method for efficiently preparing aluminum nitride from aluminum ash, and steps are as follows: the aluminum ash is finely ground and preheated, and then fluidized chlorination denitrification is carried out under the assistance of large particles, so that aluminum and aluminum nitride in the aluminum ash are converted into aluminum chloride and nitrogen; the aluminum chloride is recovered through condensation, gasified, preheated, and then reacted with magnesium nitride to generate a mixture of aluminum nitride and magnesium chloride; the mixture is crystallized and purified to obtain high-purity aluminum nitride; the by-produced magnesium chloride is electrolyzed to generate magnesium and chlorine gas; the chlorine gas is recycled for denitrification of the aluminum ash; and the magnesium is reacted with nitrogen to generate magnesium nitride and is recycled for the nitration of the aluminum chloride. The application does not need to make balls and mix carbon, the chlorination denitrification temperature is low and the efficiency is high, the aluminum nitride is prepared by nitration of the aluminum chloride with the magnesium nitride, the product is easy to separate and purify, the by-product magnesium chloride can provide magnesium and chlorine gas for the system through electrolysis, the recycling utilization rate is high, the energy utilization rate of the system is high, the harmless treatment of the aluminum ash and the large-scale efficient preparation of the aluminum nitride can be realized, and the application has good economic and social benefits.

The application relates to a silicon magnesium nitride powder, a preparation method and application thereof. The application belongs to the technical field of structural ceramic materials, and the method comprises the following steps: mixing silicon powder and a conductive agent to perform first-stage ultrafast heat treatment, synthesizing silicon nitride powder; then mixing the silicon nitride powder and magnesium powder to perform second-stage ultrafast heat treatment, synthesizing a silicon magnesium nitride coarse product; and finally performing pulse annealing treatment on the coarse product to obtain the silicon magnesium nitride powder. The obtained silicon magnesium nitride powder has the characteristics of superfine particle size (50nm-150nm), low oxygen content (<=0.15wt%) and high specific surface area (50 m 2 / g-100 m 2 / g), and is suitable for preparing high-toughness ceramic matrix composites.

The invention discloses a GaN-based P-type ohmic contact structure based on a silicon nitride and magnesium nitride composite structure and a preparation method of the GaN-based P-type ohmic contact structure, and the ohmic contact structure is arranged on a P-type GaN layer and comprises a SiN / MgN composite structure. The SiN / MgN composite structure is formed by stacking SiN layers and MgN layers of 1 to 3 cycles; wherein the thickness of the SiN layer is 1-2 nm, and the thickness of the MgN layer is 2-4 nm; the Si doping concentration of the SiN layer is 1 * 10 < 17 >-6 * 10 < 17 > cm <-3 >, and the Mg doping concentration of the MgN layer is 5 * 10 < 19 >-3 * 10 < 21 > cm <-3 >. The preparation method provided by the invention comprises the step of growing the composite structure under the conditions of 750-900 DEG C and 200-500 Torr. The high work function of MgN, the energy band bending of the SiN / PGaN interface and the tunneling effect formed by Mg diffusion are utilized to synergistically reduce the P-type ohmic contact resistance, and the beneficial effects of reducing the voltage of the device and improving the brightness and the lighting effect are achieved.

The application discloses a preparation method of passivated magnesium powder and belongs to the field of metal material passivation. The application provides the preparation method of passivated magnesium powder aiming at the problem that magnesium powder in the micro-nano level is difficult to be passivated, magnesium powder in the micro-nano level is first subjected to nitrogen treatment at high temperature to generate magnesium nitride on the surface, then is subjected to fluoride solvent treatment, the surface magnesium nitride is changed into magnesium fluoride, and then is subjected to treatment through a copper-nickel plating solution, and finally a copper / nickel-magnesium-fluoride complex structure film is formed. The method can delay the oxidation of the magnesium powder and improve the safety of the magnesium powder in the transportation, storage and use processes.

This application relates to a silicon nitride magnesium powder, its stepwise gas-pressure self-propagating preparation method, and its application, belonging to the technical field of high-performance ceramic powder materials. The method involves uniformly mixing magnesium powder, silicon nitride powder, and inorganic salt powder, placing them in a self-propagating reaction system, first performing multi-point ignition under a low-pressure argon atmosphere, and then switching to high-pressure nitrogen conditions to complete the reaction, obtaining silicon nitride magnesium composite powder; subsequently, through multi-step cleaning and low-temperature annealing treatment, the silicon nitride magnesium powder is obtained; the particle size is 1.2μm~2.5μm; the molar content of magnesium is 25%~45%, the molar content of silicon nitride is 55%~75%, the oxygen content is <0.2wt.%, and the specific surface area is 2.0m². 2 / g~8.0m 2 / g; applicable to sintering aids, refractory materials, composite material reinforcing phases and electronic packaging substrates, etc.

The application relates to a strong-interface-bonding low-carbon refractory material based on nitrogen-containing silicon magnesium nitride and a preparation method thereof. The technical scheme is as follows: aluminum powder, silicon magnesium nitride powder and fused white corundum fine powder are mixed, polyvinyl butyral is added, stirring is conducted, the mixture is placed in a tube furnace, heat preservation is conducted under the condition of a nitrogen atmosphere and 600-700 DEG C, and a composite powder is prepared. Phenolic resin is added into alcohol and stirred to obtain a mixture I, the composite powder is added into the mixture I in 1-4 times, ultrasonic dispersion is conducted, and a mixture II is obtained. Then, under stirring, fused white corundum particles, the mixture II, flake graphite and aluminum powder are sequentially added, stirring is conducted, compression molding is conducted, and solidification is conducted; after solidification, the product is placed in a high-temperature tube furnace, heat preservation is conducted at 1200-1500 DEG C under a nitrogen atmosphere, cooling is conducted to 800-1100 DEG C, heat preservation is conducted, and the strong-interface-bonding low-carbon refractory material based on nitrogen-containing silicon magnesium nitride is prepared. The application has the advantages of simple process, short production period and low synthesis temperature, and the prepared product has the advantages of uniform ceramic phase distribution, high interface bonding strength and excellent mechanical properties.

The invention relates to core-shell structure silicon nitride / silicon magnesium nitride powder as well as a preparation method and application thereof, and belongs to the technical field of structural ceramic materials. The method comprises the following steps: providing silicon nitride powder, and carrying out oxidation pretreatment to obtain silicon nitride pretreated powder with an oxidation film layer on the surface; magnesium powder is provided and heated to form magnesium steam, the silicon nitride pretreated powder is placed in a mixed atmosphere containing nitrogen and the magnesium steam to be subjected to a high-temperature sintering reaction, and composite powder is obtained; and carrying out residual magnesium removal treatment on the composite powder, and calcining to obtain the core-shell structure silicon nitride / silicon magnesium nitride powder. The silicon nitride / silicon magnesium nitride powder with the core-shell structure takes silicon nitride as a core and silicon magnesium nitride as a shell, has the advantages of promoting low-temperature high-density sintering of silicon nitride and improving the purity and performance of ceramic, and is suitable for the fields of aerospace engine parts, precision mechanical shaft pumps, cutting tools, biomedical implants, electronic packaging thermal management materials and the like.

The invention relates to silicon magnesium nitride powder as well as a step-by-step air pressure self-propagating preparation method and application thereof, and belongs to the technical field of high-performance ceramic powder materials. The method comprises the following steps: uniformly mixing magnesium powder, silicon nitride powder and inorganic salt powder, putting the mixture into a self-propagating reaction system, carrying out multi-point ignition in a low-pressure argon atmosphere, and then switching to a high-pressure nitrogen condition to complete a reaction, so as to obtain the silicon-magnesium nitride composite powder, then carrying out multi-step cleaning and low-temperature annealing treatment to obtain silicon magnesium nitride powder; the particle size is 1.2 [mu] m-2. 5 [mu] m; the molar content of magnesium is 25%-45%, the molar content of silicon nitride is 55%-75%, and the oxygen content is lt; 0.2 wt.%, the specific surface area of which is 2.0 m < 2 > / g to 8.0 m < 2 > The method is suitable for the fields of sintering aids, refractory materials, composite material reinforced phases, electronic packaging substrates and the like.

This application relates to a silicon nitride magnesium powder, its preparation method, and its applications, belonging to the technical field of structural ceramic powder materials. The preparation method includes: embedding silicon nitride powder into magnesium powder to form a magnesium-based composite powder with a micro / nano composite structure on its surface; mixing the magnesium-based composite powder with a dispersant to obtain a reaction precursor; subjecting the reaction precursor to a self-propagating synthesis reaction to obtain the silicon nitride magnesium composite powder; and sequentially subjecting the silicon nitride magnesium composite powder to acid washing and calcination treatments to obtain the silicon nitride magnesium powder. The prepared silicon nitride magnesium has a yield of over 95%, an oxygen content of less than 0.15 wt.%, and a particle size controlled between 1 μm and 2 μm with uniform distribution; it is suitable for applications such as a sintering aid for high-performance ceramics, a component of refractory materials, and a reinforcing phase in metal matrix composites.

The invention relates to a four-layer metal oxide / metal / metal / metal oxide coating that provides multispectral camouflage. Said coating having camouflage characteristics provides thermal, multispectral and electromagnetic protection by offering reflection, absorption and transmission properties against infrared (IR), ultraviolet (UV) and electromagnetic waves. As the ceramic layer, it comprises titanium dioxide (TiO₂), titanium nitride (TiN), zinc oxide (ZnO), zinc nitride (Zn₃N₂), iron (III) oxide (Fe₂O₃), iron (II) oxide (FeO), iron nitride (Fe₂N), aluminium oxide (Al₂O₃), aluminium nitride (AlN), tin oxide (SnO₂), magnesium oxide (MgO), magnesium nitride (Mg₃N₂), calcium oxide (CaO), calcium nitride (Ca₃N₂), cobalt oxide (CoO), tungsten oxide (WO₃), vanadium oxide (V₂O₅), vanadium nitride (VN), manganese oxide (MnO₃), chromium oxide (Cr₂O₃), chromium nitride (CrN), nickel oxide (NiO), boron oxide (B₂O₃), boron nitride (BN) or barium oxide (BaO). As the metal layer, copper (Cu), aluminium (Al), nickel (Ni), cobalt (Co), silver (Ag), gold (Au), iron (Fe), tungsten (W), tin (Sn), zinc (Zn), magnesium (Mg), vanadium (V), chromium (Cr), lead (Pb) or platinum (Pt) is used to provide protection against thermal cameras and UV rays, while electromagnetic waves are blocked. The adhesive-free layered structure is resistant to wear and provides versatile protection for military clothing and mobile platforms by optimising reflection and transmission.

The application relates to a high-thermal-conductivity high-strength silicon nitride ceramic and a preparation method thereof. The preparation method of the high-thermal-conductivity high-strength silicon nitride ceramic comprises the following steps: (1) wetly mixing raw material powder composed of silicon nitride powder and sintering aids to obtain raw material mixed slurry; (2) sequentially performing forming, degassing, initial sintering and resintering on the raw material mixed slurry to obtain the high-thermal-conductivity high-strength silicon nitride ceramic; wherein the sintering aids comprise: first sintering aids composed of at least one of Sc2O3, Y2O3 and lanthanide oxides and second sintering aids composed of at least one of MgO, magnesium silicide and magnesium nitride; preferably, the molar ratio of the first sintering aids to the second sintering aids is 2-4:4-8.

The invention provides a silicon-based composite negative electrode material for an all-solid-state lithium battery and a preparation method of the silicon-based composite negative electrode material. The silicon-based composite negative electrode material for the all-solid-state lithium battery comprises the following components in percentage by mass: 55-90% of a silicon substrate, which comprises silicon powder or a silicon carbon material; the magnesium doping agent comprises magnesium powder and magnesium nitride, and the mass fraction of the magnesium doping agent is 5%-40%; and the auxiliary component comprises a conductive agent and an adhesive. According to the silicon-based composite negative electrode material for the all-solid-state lithium battery and the preparation method of the silicon-based composite negative electrode material, metal magnesium and magnesium nitride are doped into a silicon-based negative electrode, so that collaborative lithium storage of silicon and lithium deposition is realized, lithium dendrite growth can be effectively inhibited, interface contact is improved, rate performance is improved, and energy density and cycling stability are improved.

The invention relates to magnesium silicon nitride powder as well as a preparation method and application thereof. Belongs to the technical field of structural ceramic materials. Then mixing the silicon nitride powder with magnesium powder, and carrying out secondary ultra-fast heat treatment to synthesize a silicon magnesium nitride crude product; and finally, carrying out pulse annealing treatment on the crude product to obtain the magnesium silicon nitride powder. The obtained silicon magnesium nitride powder has the characteristics of ultrafine particle size (50nm-150nm), low oxygen content (less than or equal to 0.15 wt%) and high specific surface area (50m < 2 > / g-100m < 2 > / g), and is suitable for preparing a high-toughness ceramic matrix composite material.

The present invention relates to an anode for a lithium secondary battery, a method for preparing same, and a lithium secondary battery comprising same, the anode comprising: a current collector; and a protective layer positioned on the current collector, wherein the protective layer contains magnesium nitride (Mg3N2), amorphous carbon, and a binder.

This invention discloses a nano-cubic boron nitride material and its synthesis method, belonging to the technical field of cubic boron nitride materials. First, hexagonal boron nitride is modified by hydroxylation to obtain hydroxyl-rich hexagonal boron nitride. Aluminum hydroxide is grown in situ on the surface of the hydroxyl-rich hexagonal boron nitride using aluminum nitrate hexahydrate as the aluminum source. After high-temperature nitrogen calcination, alumina-supported hexagonal boron nitride is obtained. Then, a nitriding reaction occurs under a high-temperature ammonia atmosphere to obtain aluminum-supported hexagonal boron nitride. The modified hexagonal boron nitride is mixed with lithium magnesium nitride and molded, then subjected to a catalytic phase transition reaction under high temperature and pressure. Finally, it is refined through a gradient purification process to obtain the nano-cubic boron nitride material. By hydroxylating the matrix and constructing the nano-aluminum nitride active phase in situ, the compatibility between the catalyst and the matrix interface is optimized, and microscopic defects at grain boundaries are reduced, giving the material excellent thermal and structural stability, meeting the long-term stable service requirements of precision grinding applications.

The invention relates to a chemical vapor deposition technology for preparing a wide bandgap semiconductor material, and provides a hexagonal boron nitride film, a preparation method thereof, an energy band regulation and control method and a wide spectrum ultraviolet photoelectric detector. Magnesium nitride is used as a doping source, and the doping source is synchronously introduced to the epitaxy of an h-BN film by adopting a chemical vapor deposition method; in-situ doping of the magnesium element in an h-BN crystal lattice is achieved, and the forbidden band width of the h-BN film is regulated from 5.91 eV to 3.38 eV by controlling the magnesium doping concentration. According to the magnesium-doped h-BN film, a wide-spectrum ultraviolet photoelectric detector is prepared based on the magnesium-doped h-BN film, the ultraviolet light absorption range is widened to the wave band of 185-365 nm, and wide-spectrum and high-sensitivity ultraviolet detection is achieved. The doping process is controllable, the energy band regulation and control effect is remarkable, the spectral response limitation of an intrinsic h-BN-based detector is broken through, and the application of a photoelectric device in the fields of environmental monitoring, biochemical analysis and the like is promoted.

This invention discloses an integrated continuous magnesium nitridation hydrolysis ammonia supply system and method, relating to the fields of new energy and ammonia energy. The system includes a high-temperature reaction unit, a continuous hydrolysis reaction unit, and a waste recovery unit. The high-temperature reaction unit is used for the nitridation reaction of magnesium powder and nitrogen gas, and unreacted nitrogen gas is condensed and refluxed to participate in the nitridation reaction again. The continuous hydrolysis reaction unit is used to receive the magnesium nitride generated by the nitridation reaction, drive the magnesium nitride to flow and contact the sprayed reaction liquid to undergo a hydrolysis reaction, generating ammonia gas and reaction byproducts. The waste recovery unit is used to clean and collect the reaction byproducts flowing within the hydrolysis reaction unit. This invention has a reasonable structure; the reaction process in the metal nitridation and hydrolysis ammonia production system is controllable, the reaction is continuous, the products are easy to recover, the ammonia is easy to store, and maintenance time is short.

The invention relates to a whisker modified resin reinforced magnesium silicon nitride material and a preparation method thereof. According to the technical scheme, the preparation method comprises the following steps: by taking magnesium silicon nitride whiskers as reinforcements, performing ultrasonic dispersion through sodium dodecyl benzene sulfonate, then introducing iron nitrate nonahydrate as a magnetic modified precursor, and performing segmented heating reduction heat treatment under a protective atmosphere to form magnetic components on the surfaces of the whiskers so as to obtain a magnetic modified whisker mixture III; magnetically stirring the mixture III and resin in ethanol to form a pre-impregnated reinforcement mixture IV; and finally, mixing the reinforcement with magnesium silicon nitride ceramic powder, compacting, and sintering in a nitrogen atmosphere by adopting a two-stage heating system to finally prepare the whisker modified resin reinforced magnesium silicon nitride material. The crystal whisker modified resin reinforced magnesium silicon nitride material has the characteristics of good dispersity, matched thermal expansion coefficient and matched weak interface bonding strength, and the prepared crystal whisker modified resin reinforced magnesium silicon nitride material has excellent mechanical properties.

The invention discloses a cubic boron nitride polycrystal and a preparation method thereof, and belongs to the technical field of superhard material preparation, the method comprises the following steps: mixing hexagonal boron nitride with two self-synthesized modified compounds silicon functionalized polyborazine and boric acid functionalized polysilazane, magnesium nitride and nano silicon powder, and carrying out ball milling drying and cold press molding to obtain a biscuit; the preparation method comprises the following steps: carrying out stepped heating heat treatment on a green body in a protective atmosphere to finish the stabilization of a precursor, and then carrying out reactive sintering under high-temperature and high-pressure conditions to finally prepare the cubic boron nitride polycrystal. The two modified compounds are converted into stable ceramic phases in heat treatment, and cooperate with a magnesium nitride catalyst, so that the conversion of hexagonal boron nitride to a cubic phase is remarkably promoted, and a grain boundary structure is optimized. The prepared cubic boron nitride polycrystal has the characteristics of high purity, good compactness, high hardness and excellent thermal stability.

This invention relates to the preparation of wide bandgap semiconductor materials using chemical vapor deposition (CVD) technology. It provides hexagonal boron nitride (h-BN) thin films, their preparation methods, bandgap modulation methods, and a broadband ultraviolet photodetector. Using magnesium nitride as the dopant source, the dopant source is simultaneously introduced into the epitaxial layer of the h-BN thin film via CVD, achieving in-situ doping of magnesium in the h-BN lattice. By controlling the magnesium doping concentration, the bandgap of the h-BN thin film is modulated from 5.91 eV to 3.38 eV. Based on this magnesium-doped h-BN thin film, a broadband ultraviolet photodetector is also prepared, broadening the ultraviolet absorption range to the 185-365 nm band, achieving wide-spectrum, high-sensitivity ultraviolet detection. The doping process of this invention is controllable, and the bandgap modulation effect is significant, breaking through the spectral response limitations of intrinsic h-BN-based detectors and promoting the application of optoelectronic devices in environmental monitoring, biochemical analysis, and other fields.

The invention provides a double-layer coated porous silicon material as well as a preparation method and application thereof, and relates to the technical field of lithium ion battery materials. The material is of a core-shell type composite structure and sequentially comprises a porous silicon core, an inner-layer-coated magnesium silicon nitride layer and an outer-layer-coated carbon shell. According to the structure, silicon magnesium nitride grows on the surface of a porous silicon framework in situ and is used for enhancing mechanical support and improving ion transmission efficiency; and the external uniform and compact carbon layer provides an electron conduction path and isolates the electrolyte, so that the interface stability is improved. The preparation method comprises the steps of alloying, ammonia nitrogen atmosphere step-by-step nitriding, carbon source coating, carbonization treatment, acid pickling and the like, the process is controllable, and the structural hierarchy is clear. The obtained material shows excellent electrochemical performance under high-rate and long-cycle conditions, and is suitable for preparation of a high-performance lithium ion battery negative electrode material.