28 results about "Iron nitride" patented technology

The invention relates to the technical field of welding materials, and particularly discloses a high-temperature-resistant flux-cored wire containing rare earth elements and a preparation method of the high-temperature-resistant flux-cored wire. The high-temperature-resistant flux-cored wire containing the rare earth elements comprises a welding wire skin and a flux core. The flux core comprises the following raw materials of dehydrated rutile, dehydrated potassium feldspar, zircon sand, metal chromium powder, metal nickel powder, electrolytic manganese, ferrotitanium, ferro-aluminum, potassium cryolite, potassium titanate, sodium titanate, fine iron powder, yttrium-based iron alloy powder, atomized ferrosilicon, nitrided ferrochrome, bismuth oxide, auxiliaries and the balance reduced iron powder. The auxiliary agent is a mixture of a zirconium-iron alloy, a titanium-iron alloy and an aluminum-magnesium alloy. A specific alloy auxiliary is introduced into the flux core to protect stable transition of rare earth yttrium, yttrium and multiple components synergistically optimize the weld joint performance, 253MA heat-resistant steel is matched, slag and electric arc regulation and control components and a reasonable process are matched, and the welding quality of the welding wire is improved.

The invention discloses a preparation method of a high-hydrogen-resistance pure iron nitriding composite diaphragm, which comprises the following steps: putting a matrix into a controllable atmosphere well type nitriding furnace, raising the temperature in the controllable atmosphere well type nitriding furnace to 460-500 DEG C at the temperature raising rate of 5-15 DEG C / min, and carrying out heat preservation for 2-6 hours to nitride the matrix; the base body is placed in a uniform temperature area of a tubular vacuum heat treatment furnace, the tubular vacuum heat treatment furnace is vacuumized, the temperature in the tubular vacuum heat treatment furnace is increased to 480-520 DEG C at the speed of 5-15 DEG C / mi, and heat preservation is conducted for 0.5-2 hours; taking out the matrix after the temperature in the tubular vacuum heat treatment furnace is reduced to room temperature; the hydrogen resistance of the prepared composite diaphragm can reach 13 times that of a pure iron matrix, the performance improvement amplitude is far higher than 3 times that of single gas nitriding treatment, and the composite diaphragm has the characteristics of good mechanical stability and strong deformation resistance.

The invention relates to the technical field of catalyst preparation, and provides an iron-based catalyst, a preparation method and application thereof, and a method for preparing olefin from synthesis gas. The iron-based catalyst comprises 30-60 parts by mass of a carrier and 40-70 parts by mass of an active component, the active component comprises a composition of which the chemical formula is Fe100AaKbOx (Fe4N) c according to an atomic ratio; wherein A comprises at least one of Mo, W and Cr, the value range of a is 5-30, the value range of b is 1-10, the value range of c is 10-25, and x is the total number of oxygen atoms required by valence of each element in the catalyst. The iron-based catalyst provided by the invention simultaneously contains an iron oxide and an iron nitride, can be used for Fischer-Tropsch synthesis, and is beneficial to improvement of olefin selectivity; the CO conversion rate and the olefin selectivity can be further improved by limiting the ratio of iron oxide to iron nitride on the surface of the catalyst; and the method is suitable for a fluidized bed reactor, and can effectively solve the problem of difficulty in heat removal in high-temperature Fischer-Tropsch synthesis.

The invention belongs to the technical field of environmental functional materials and soil remediation, and particularly relates to a micron-sized zero-valent iron nitride catalyst as well as a preparation method and application thereof. The invention provides a nitrided micron zero-valent iron catalyst which is prepared by doping micron-sized iron powder with urea, the nitrogen content of the catalyst is 0.5 wt%-4.5 wt%, and the particle size of the micron-sized iron powder is 10-300 microns. The preparation method comprises the following steps: putting raw materials urea and micron-sized iron powder into a ball milling tank, adding grinding balls, and carrying out ball milling for 2-10 hours at the rotating speed of 450-550rpm in an air atmosphere; and drying the product after ball milling is finished, thereby obtaining the product. The catalyst is not only suitable for efficient deep treatment of high-concentration organic contaminated leacheate, but also can be directly used for chemical oxidation remediation of contaminated soil, and has remarkable engineering application value.

According to an exemplary embodiment of the present invention, provided is an ammonia decomposition system capable of minimizing the generation of iron nitride as a by-product.

The application discloses a composite heat insulation material with wave absorption performance, a multilayer phase interface structure containing the composite heat insulation material and a preparation method of the multilayer phase interface structure; the composite heat insulation material comprises: a heat insulation material and a wave absorber, wherein the heat insulation material is yttrium zirconium oxide YSZ powder; the wave absorber is samarium iron nitride SmFeN powder; the mass ratio of the heat insulation material to the wave absorber is 1:1; the multilayer phase interface structure containing the composite heat insulation material comprises: a YSZ / SmFeN uniform mixing structure, an interface structure parallel to incident electromagnetic waves, an interface structure vertical to the incident electromagnetic waves and a periodic arrangement interface structure containing both the interface vertical to the incident electromagnetic waves and the interface parallel to the incident electromagnetic waves.

The invention relates to the field of functional polymer materials, and discloses a samarium-iron-nitrogen magnetic EPDM (Ethylene-Propylene-Diene Monomer) foamed rubber composite material and a preparation method thereof.The preparation method comprises the following steps: firstly, uniformly dispersing samarium-iron-nitrogen magnetic powder in an EPDM (Ethylene-Propylene-Diene Monomer) matrix by adopting a mechanical blending method, and forming a foamed rubber matrix with an open-pore or closed-pore structure by adopting a two-stage vulcanization process; and finally, magnetizing by adopting a single-sided multi-stage magnetizing device to obtain the magnetic EPDM foamed rubber composite material. According to the preparation method provided by the invention, the samarium-iron-nitrogen magnetic EPDM foamed rubber composite material with excellent magnetic property, good mechanical property and relatively high foaming ratio can be obtained, the sealing property can be improved by utilizing the excellent magnetic property, and the samarium-iron-nitrogen magnetic EPDM foamed rubber composite material has a good application prospect in the field of magnetic sealing.

The invention provides a preparation method of samarium-iron-nitrogen magnetic powder, which comprises the following steps: mixing iron, samarium oxide and rare earth hydride (as a reducing agent, preferably lanthanum hydride and / or cerium hydride), performing ball milling treatment, and performing briquetting treatment on the obtained mixed material to obtain a green body; performing vacuum heat treatment on the green body to obtain a coarse samarium ferromagnetic powder material; crushing the coarse samarium-iron magnetic powder material, placing the crushed coarse samarium-iron magnetic powder material in an ammonia atmosphere, and carrying out high-temperature nitriding treatment to obtain coarse samarium-iron-nitrogen magnetic powder; and transferring the crude samarium-iron-nitrogen magnetic powder into a washing solution for cleaning treatment so as to remove residual non-magnetic impurities in a solid phase, thereby obtaining the samarium-iron-nitrogen magnetic powder, the preparation method for preparing the samarium-iron-nitrogen magnetic powder has the advantages of being small in reducing agent dosage, low in heat treatment temperature, short in time and the like, and the preparation cost of the samarium-iron-nitrogen magnetic powder is effectively reduced.

The invention relates to the technical field of catalyst preparation, and provides an iron catalyst, a preparation method and application thereof, and a method for preparing olefin through carbon dioxide hydrogenation. The iron catalyst comprises an active component and a carrier in a mass ratio of (40-70): (30-60), the active component comprises a composition with a chemical formula of Fe < 100 > A K O < x > (Fe < 4 > N) < c > according to an atomic ratio; wherein A comprises at least one of Mn, Cu and Zn, the value range of a is 10-30, the value range of b is 1-10, the value range of c is 1-8, and x is the total number of oxygen atoms required by valence of each element in the catalyst. The iron catalyst provided by the invention simultaneously contains an iron oxide and an iron nitride, can be used in a reaction for preparing olefin through carbon dioxide hydrogenation, and is beneficial to improving the conversion rate of carbon dioxide and the selectivity of olefin, especially C4 + olefin; and the method is suitable for a fluidized bed reactor, and can effectively solve the problems of difficulty in heat removal, easiness in temperature runaway and easiness in catalyst deactivation in high-temperature Fischer-Tropsch synthesis.

All example composition may include a plurality of grains including an iron nitride phase. The plurality of grains may have an average wain size between about 10 nm and about 200 nm. An example technique may include treating a composition including a plurality of grains including au iron-based phase to adjust an average grain size of the plurality of grains to between about 20 nm and about 100 ma. The example technique may include nitriding the plurality of grains to form or grow an iron nitride phase.

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 disclosure describes techniques for forming nanoparticles including Fe16N2 phase. In some examples, the nanoparticles may be formed by first forming nanoparticles including iron, nitrogen, and at least one of carbon or boron. The carbon or boron may be incorporated into the nanoparticles such that the iron, nitrogen, and at least one of carbon or boron are mixed. Alternatively, the at least one of carbon or boron may be coated on a surface of a nanoparticle including iron and nitrogen. The nanoparticle including iron, nitrogen, and at least one of carbon or boron then may be annealed to form at least one phase domain including at least one of Fe16N2, Fe16(NB)2, Fe16(NC)2, or Fe16(NCB)2.

Disclosed in the present invention is a preparation method for a micron-sized high-purity α"-Fe16N2 magnetic powder. The preparation method comprises the following steps: 1) sequentially performing high-pressure roller milling, high-energy grinding, and drying treatment on an iron ore concentrate to obtain a micron-sized fine particulate iron oxide powder; 2) performing hydrogen reduction on the micron-sized fine particulate iron oxide powder to obtain a porous active reduced iron powder, wherein the temperature for the hydrogen reduction is controlled within a range of 50ºC below the critical temperature of a reduction transformation pathway; and 3) performing nitriding on the porous active reduced iron powder in an ammonia gas atmosphere to obtain α"-Fe16N2 iron nitride. The method uses an inexpensive iron ore concentrate as a raw material, has a low cost and a simple process, can achieve mass production, and can obtain a micron-sized high-purity α"-Fe16N2 iron nitride powder, which can be then formed by means of a conventional additive manufacturing method to produce a high-performance magnet.

The invention belongs to the technical field of new energy materials, and particularly relates to an iron nitride / gallium nitride / carbon composite heterostructure material and a preparation method and application thereof. In a protective atmosphere, the iron-containing raw material, the gallium-containing raw material and the nitrogen-containing organic compound are subjected to heat treatment, so that the iron-containing raw material and the gallium-containing raw material are subjected to reduction and nitridation reaction, an iron nitride phase and a gallium nitride phase are formed, meanwhile, a carbon phase is formed, and the iron nitride / gallium nitride / carbon composite heterostructure material is obtained. The nitrogen-containing organic compound is introduced under the inert atmosphere condition, so that the iron source and the gallium source are synchronously subjected to reduction and nitridation reactions in the heat treatment process, in-situ synergistic generation of iron nitride and gallium nitride is achieved, an iron nitride phase and a gallium nitride phase form a heterostructure interface on the nanoscale, and the performance of the device is improved. And a stable composite heterostructure is constructed under the confinement effect of a carbon phase, so that the problems that in the prior art, multi-phase materials are difficult to synergistically form, the interface effect is insufficient, the process condition is harsh and the like are solved.

This invention belongs to the field of bonded permanent magnet materials technology, and discloses a high-density molded bonded samarium iron nitride (SMR) magnet and its preparation method. Addressing the shortcomings of existing molded magnets, such as low density, poor magnetic properties, and rapid mold wear, the magnet is made of 80%-95% SMR magnetic powder, binder, and other raw materials, achieving a density ≥7.3 g / cm³ and a maximum magnetic energy product ≥10.5 MGOe. A high-performance, detachable composite mold core, layered venting grooves, and a pressure mold with built-in magnetic field coils are employed. Combined with a preparation process of layered feeding, three-stage directional pressurization, and constant temperature pressure holding, the magnetic powder orientation and air expulsion are synchronized, improving magnet performance and mold life. This method is suitable for industrial mass production and can be applied in fields such as automotive motors and precision instruments.

The invention provides a flux core for high manganese steel, a welding wire, application and deposited metal. The flux core comprises the following components: 32.0 to 45.0 wt% of metal manganese, 18.0 to 32.0 wt% of nickel powder, 6.0 to 12.0 wt% of aluminum powder, 0.7 to 1.5 wt% of graphite, 4.0 to 8.0 wt% of nitrided ferrochrome, 2.0 to 2.5 wt% of chromium carbide, 1.5 to 3.5 wt% of rare earth ferrosilicon, 1.0 to 2.5 wt% of nickel-magnesium alloy, 1.0 to 2.0 wt% of aluminum-magnesium alloy, 5.0 to 8.0 wt% of rutile, 3.0 to 5.0 wt% of potassium feldspar and 0.5 to 2.5 wt% of zirconium quartz. According to the flux-cored wire, Mn, C, Ni, Cr and other alloy elements are reasonably matched, a certain amount of Al element is added, the stacking fault energy is improved, the Mn content is reduced on the premise that the weld joint structure and low-temperature toughness are ensured, the problems that an existing flux-cored wire is large in welding smoke and serious in manganese steam are effectively solved, and the low-harm and efficient welding requirements of high manganese steel are met.

The invention relates to a method for reducing the content of iron nitrides in sponge iron (1), the temperature of the sponge iron (1) being adjusted to a temperature of at least 450°C. In a method for producing a metal melt comprising melting sponge iron (1), a sponge iron that has been denitrided in this way and has a temperature of 450°C to 1000°C is used. A device for reducing (2) the content of iron nitrides in sponge iron (1) comprises a first container (3) for receiving sponge iron (1) and a heating device (4) for setting a temperature of at least 450°C for sponge iron (1) in the first container (3). A device for feeding (8) sponge iron (1) to a melting device (9) for melting sponge iron (1) comprises a device for reducing (2) the content of iron nitrides in sponge iron (1) and a feed line (10) for feeding sponge iron (1), from the device for reducing (2) the content of iron nitrides in sponge iron (1), into the melting device (9).

This invention belongs to the field of functional materials technology and relates to a samarium iron nitride (SFIN)-based anisotropic bonded magnet and its manufacturing method. The manufacturing method includes the following steps: loading magnetic particles into a mold, pre-magnetizing them with a rapidly changing magnetic field, then further magnetizing them with a rapidly changing magnetic field, and applying pressure under the rapidly changing magnetic field to densify the magnetic powder; after demolding, a molded blank is obtained; the molded blank is heated to cross-link and solidify the binder, thus obtaining the target magnet. The manufacturing method provided by this invention not only improves the magnet orientation ability and magnet density under high-temperature pressing (HTPP) technology, obtaining high-performance, high-density SFIN-based bonded magnets with higher magnetism and density than existing technologies, but also significantly improves the orientation ability and magnet density of SFIN-based bonded magnets under low-temperature pressing (HTPP) and room-temperature pressing (room-temperature pressing) technologies, achieving low-temperature, room-temperature, and high-efficiency manufacturing processes for high-performance bonded magnets.

A secondary battery (5) and its preparation method and power supply device are disclosed. The secondary battery (5) includes a positive electrode, a negative electrode, and a separator (10). The separator (10) is located between the positive electrode and the negative electrode. The separator (10) includes a first polymer layer (101) and a material layer (102) disposed on the first polymer layer (101). The material layer (102) includes inorganic materials, including one or more of lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, lithium aluminum titanium germanium phosphate, lithium aluminum titanium phosphate, lithium aluminum tantalum titanium phosphate, lithium tetrathiophosphate, lithium germanium phosphorus sulfide, lithium phosphorus sulfide, iron oxide, copper oxide, titanium dioxide, tin dioxide, manganese dioxide, zinc oxide, zirconium dioxide, chromium nitride, vanadium nitride, nickel nitride, iron nitride, graphene oxide, graphene oxide, fluorinated graphite, fluorinated graphene, fluorinated carbon nanotubes, and fluorinated carbon fibers. The secondary battery (5) has excellent high-rate cycle performance and a long service life.

The application relates to the technical field of magnetic materials, and discloses a praseodymium-coated samarium iron nitride powder and a preparation method thereof. The praseodymium-coated samarium iron nitride powder comprises a samarium iron nitride powder and a coating layer coated on the outer surface of the samarium iron nitride powder; and the material of the coating layer is pure metal. The praseodymium-coated samarium iron nitride powder material is obtained through process steps of pretreatment, target material feeding, target surface pretreatment, coating and post-treatment. The praseodymium-coated samarium iron nitride powder is prepared by a magnetron sputtering device under airtight and oxygen-free conditions, the oxidation degree of the powder is reduced from the source, the oxygen content of the obtained product is significantly lower than that of a product prepared by a traditional process, the dense praseodymium coating layer prevents oxygen and water from invading and avoids process pollution and powder agglomeration, and the praseodymium and the samarium iron nitride produce a magnetic performance synergistic effect, so that the comprehensive magnetic performance of the powder, such as residual magnetism, intrinsic coercive force and magnetic energy product, is effectively improved.

The disclosure is directed to an iron-nitride material having a polycrystalline microstructure including a plurality of elongated crystallographic grains with grain boundaries, the iron-nitride material including at least one of an α″-Fe16N2 phase and a body-center-tetragonal (bct) phase comprising Fe and N. The disclosure is also directed a method producing an iron-nitride material. The method includes some combinations of preparing a raw material comprising iron, carrying out a microstructure build-up by annealing the prepared raw material at an elevated temperature and subsequently quenching the prepared raw material to produce a microstructure build-up material, annealing the microstructure build-up material, reducing the microstructure build-up material in a hydrogen environment, nitriding the reduced material to produce a nitrided material and subsequently quenching the nitrided material to a martensitic transformation temperature, stress annealing the nitrided material, and magnetic field annealing the stress-annealed material.

The invention discloses a preparation method of a ceramic bond sintered samarium-iron-nitrogen permanent magnet, and belongs to the field of rare earth permanent magnet materials. Low-temperature ceramic is adopted as a binding agent, samarium-iron-nitrogen powder and low-temperature ceramic powder are mixed and then subjected to magnetic field orientation, preheating and prepressing, then hot pressed sintering is conducted at the temperature of 500-600 DEG C, and the sintered samarium-iron-nitrogen permanent magnet is prepared. The high-density and high-magnetic-performance samarium-iron-nitrogen permanent magnet is obtained by using the low-temperature ceramic binding agent to activate the sintering process, and the volume ratio of the binding agent is reduced, so that the magnetic performance advantage of samarium-iron-nitrogen is brought into full play, and a magnet piece in a thermal demagnetization state can be obtained according to requirements. The prepared sintered samarium-iron-nitrogen permanent magnet can be applied to the fields of new energy automobiles, industrial motors, robots, consumer electronics, medical equipment and the like, the cost can be reduced, the requirements for miniaturization and corrosion resistance can be met, and the sintered samarium-iron-nitrogen permanent magnet is adaptive to precise devices.

The application discloses a nitrogen vacancy-rich ferrocyanide coupled cobalt catalytic electrode and a preparation method thereof, which comprises a base electrode, a carrier layer and an active layer which are sequentially coated on the base electrode; the carrier layer is an Fe2N layer, and the active layer is a cobalt elementary sub-nanometer cluster layer; the loading capacity of the cobalt elementary sub-nanometer cluster layer is 50-600 μg / cm 2 The ferrocyanide coupled cobalt catalytic electrode has high activity and high stability, can construct a bifunctional synergistic catalytic system of "nitrogen vacancy stable active hydrogen + cobalt cluster activated C-Cl bond", and improves the electrochemical reduction dehalogenation efficiency on halogen-containing organic pollutants.

The application relates to the technical field of magnetic materials, in particular to a samarium iron nitrogen / samarium aluminum copper composite material and a preparation method thereof. The samarium iron nitrogen / samarium aluminum copper composite material comprises samarium iron nitrogen, samarium aluminum copper, a surfactant and a binder; wherein the chemical formula of the samarium iron nitrogen is Sm2Fe 17 N3; the samarium iron nitrogen / samarium aluminum copper composite material reduces the oxidation of a samarium iron nitrogen phase, improves the coercive force of the samarium iron nitrogen / samarium aluminum copper composite material, and has the antioxidant and anticorrosion abilities and better magnetic properties through the addition of the surfactant.

The application relates to the technical field of steel materials, in particular to a high-wear-resistance steel material for a pipe mold and a preparation process thereof, which comprises the following preparation steps: step S1: smelting, step S2: casting and heat treatment, and step S3: preparation of the high-wear-resistance steel material for the pipe mold. In the smelting process, an inoculation modifier composed of an Al-Ti-Nb intermediate alloy and a vanadium iron nitride alloy is used, the Al-Ti-Nb intermediate alloy and the vanadium iron nitride alloy can play a mutual synergistic effect, and the strength and toughness of the steel material body can be improved; through high-temperature solid solution treatment at 1030-1040 DEG C and twice tempering treatment at 540-560 DEG C, the toughness of the steel material body is optimized on the basis of maintaining high hardness, the balance between hardness and toughness is realized; in the preparation process of the high-wear-resistance steel material for the pipe mold, laser cladding material mixed by AlCoCrNiTiB alloy powder and nano ytterbium oxide powder is used to perform surface modification on the steel material body, so that the high-wear-resistance steel material for the pipe mold simultaneously has the characteristics of low friction and wear resistance.

This invention relates to the field of samarium iron nitride (SFeNi) permanent magnet material manufacturing technology, and discloses a method and system for optimizing SFeNi injection molding process parameters using digital twins. This method achieves dynamic optimization by integrating a digital twin with the physical production line. Real-time sensor data from the production line is collected and preprocessed. Based on this, a digital twin containing a particle layer, a melt layer, and a magnetic pole layer is constructed and updated. Using this twin, the agglomeration and orientation of SFeNi particles are predicted in the particle layer, temperature, shear, and magnetic flux distribution are simulated in the melt layer, and magnetic performance indicators are evaluated in the magnetic pole layer. Based on these predictions and evaluations, the material temperature, injection speed, pulsating magnetic field waveform, and holding pressure curve are optimized using an artificial intelligence proxy model. Finally, the optimized parameters are sent to the production line for execution via a programmable logic controller (PLC). This method achieves online adaptive adjustment of process parameters, improving the quality and efficiency of magnet molding.

The application provides a preparation method of samarium-iron-nitrogen magnetic powder, which comprises the following steps: mixing iron, samarium oxide and rare earth hydride (as a reducing agent, preferably lanthanum hydride and / or cerium hydride), performing ball milling treatment, and performing briquetting treatment on the obtained mixture to obtain a blank; performing vacuum heat treatment on the blank to obtain a coarse samarium-iron-magnetic powder material; placing the coarse samarium-iron-magnetic powder material into an ammonia atmosphere after performing crushing treatment, and performing high-temperature nitriding treatment to obtain a coarse samarium-iron-nitrogen magnetic powder; and transferring the coarse samarium-iron-nitrogen magnetic powder into a washing liquid to perform cleaning treatment, so as to remove the residual non-magnetic impurities in the solid phase, and obtain the samarium-iron-nitrogen magnetic powder; the preparation method provided by the application has the advantages of small reducing agent dosage, low heat treatment temperature, short time, etc., and effectively reduces the preparation cost of the samarium-iron-nitrogen magnetic powder.

This invention discloses an iron-nitride-based amorphous and nanocrystalline electromagnetic wave absorbing material, its preparation method, and its applications. The material comprises an in-situ generated Fe4N phase, which forms a composite structure with an iron-based amorphous and / or nanocrystalline matrix. The material possesses a composite phase structure of the amorphous phase and Fe4N phase, or an amorphous phase, α-Fe(Si) phase, and Fe4N phase. The preparation method involves a three-step nitriding treatment of iron-based amorphous and / or nanocrystalline powder: first, stress-relief heat treatment in a nitrogen atmosphere; second, reduction heat treatment in a mixed atmosphere of nitrogen and hydrogen; and third, nitriding heat treatment in a mixed atmosphere of hydrogen and ammonia, resulting in the in-situ generation of the Fe4N phase. This invention can improve the dielectric loss of the material, optimize impedance matching, and enhance electromagnetic wave absorption performance. This material has a minimum reflection loss of -73.28dB in the 1-18GHz frequency band, a -10dB bandwidth of up to 1.99GHz, and a matching thickness as low as 3.85mm. It can be applied to electromagnetic wave absorbing devices in fields such as high-frequency communication, radar detection, and remote sensing navigation.