35results about How to "Improve eddy current loss" patented technology

The invention discloses non-oriented electrical steel with excellent magnetic performance and Rm not smaller than 600 MPa, wherein the non-oriented electrical steel is composed of the following components by weight percent: 2.5-3.5% of Si, 0.1-1.0% of Mn, not more than 1.0% of Ni and Al, not larger than 0.005% of N, not larger than 0.015% of S, not larger than 0.003% of C and not larger than 0.05% of P; the production steps are as follows: smelting and continuously casting a bloom; heating the continuously cast bloom; hot rolling; coiling; normalizing; pickling and cold rolling; continuous annealing; and naturally cooling to the room temperature for future use. The mechanical properties and magnetic performance of the non-oriented electrical steel disclosed by the invention can simultaneously satisfy the requirements of motor steel, namely, Rm is not smaller than 600 MPa, Rel is not smaller than 500 MPa, P1.0/400 is not larger than 17 W/kg, B 5000 is not smaller than 1.66 T, and stators and rotors are processed by the same electromagnetic steel plate to reduce the time and material costs.

The invention provides a magnetic core material, and a preparation method and an application thereof. The magnetic core material comprises a first magnetic powder, a second magnetic powder and a third magnetic powder which are bonded and mixed by a binder. The preparation method comprises the following steps: (1) mixing the first magnetic powder, the second magnetic powder and the third magnetic powder to obtain a ternary magnetic powder; (2) passivating the ternary magnetic powder obtained in the step (1) to obtain a passivated magnetic powder; (3) coating the passivated magnetic powder obtained in the step (2) to obtain a coated magnetic powder; (4) bonding and granulating the coated magnetic powder obtained in the step (3) to obtain magnetic particles; and (5) carrying out compression molding on the magnetic particles obtained in the step (4) to obtain the magnetic core material. The magnetic core material provided by the invention has the characteristics of low forming pressure, high magnetic conductivity and low loss, and the short-circuit risk of a molded inductor is reduced.

The invention relates to a preparation method of a foam aluminium alloy wave-absorbing material, comprising surface pretreatment of foam aluminium alloy substrates, preparation of wave-absorbing coating and spraying of the wave-absorbing coating. The preparation method of the wave-absorbing material comprises the following steps of: (1) adding a coupling agent to polyaniline, adding a rare earth oxide after ball milling wet mixing, drying after ball milling wet mixing, and dry mixing to prepare a composite filler; (2) adding the coupling agent to the composite filler to prepare a coupling filler; (3) uniformly mixing a dispersing agent and a diluent, and adding the mixture to the coupling filler to prepare a dispersed filler; and (4) mixing epoxide resin with polyamide to prepare a film forming matter, grinding the film forming matter together with the dispersed filler, mixing, stirring, carrying out sonic oscillation, stirring and sieving, wherein the screenings are used as wave-absorbing coating. The wave-absorbing agent foam aluminium alloy-based wave-absorbing material doped with rare earth oxide has excellent wave-absorbing performance, and the bandwidth lower than -10dB can reach 13.5GHz in the frequency range of 26.5GHz to 40.0GHz.

The invention discloses a six-pole mixed magnetic bearing. The rotors are coaxially sleeved with left stator iron cores and right stator iron cores which are symmetrically arranged in the axial direction, left stress discs are arranged at the left ends of the rotors, and right stress discs are arranged at the right ends of the rotors, and circular ring-shaped permanent magnets are laminated between yoke portions of the left stator iron cores and the right stator iron cores; the permanent magnets are axially magnetized, six stator magnetic poles are uniformly distributed in each of the left stator iron cores and the right stator iron cores in the circumferential direction, the six stator magnetic poles of each left stator iron core are aligned with the corresponding left stress disc in theradial direction, and the six stator magnetic poles of each right stator iron core are aligned with the corresponding right stress disc in the radial direction; and the two radial control coils whichare in face-to-face and radial direction on the same stator iron core in the left stator iron core and the right stator iron core are connected in series with a same winding direction, and the two radial control coils which are in axial-facing direction on the left stator iron core and the right stator iron core are connected in series with an opposite winding direction. According to the six-polemixed magnetic bearing, suspension force and displacement characteristics and suspension force and current characteristics tend to be linear, and coupling between two radial degrees of freedom is reduced.

The invention relates to an external circulation bypass structure between converter transformer core pulling plate columns, in particular to a circulation bypass structure between large-capacity converter transformer core pulling plate columns, and belongs to the technical field of transformer manufacturing. According to the technical scheme, a plurality of copper cables (4) are arranged in a conductor grip frame (3), the copper cables are connected with coil outgoing wires and then connected with an upper clamp and a lower clamp, and the copper cables, the upper clamp, the lower clamp and core main column pulling plates form short circuit rings (2) along core windows. The external circulation bypass structure has the advantages that on the premise that the structure and the strength of the pulling plates are not changed, losses of the pulling plates are reduced, eddy current losses of cores are greatly reduced, leakage flux is restrained, the structure is simple, and layout is reasonable.

The invention relates to a magnetic fluid sieving device, which mainly comprises a fluid separation sieve and a magnetic loop. The device is characterized in that magnetic wires and nonmagnetic wires in the fluid separation sieve formed by multiple layers of screen meshes in a plurality of independent fluid separation cavities under magnetic poles divide a magnetic field space into several minimal spaces of high gradient magnetic potentials and an equal magnetic potential; magnetic particles in a fluid are enriched in the high gradient magnetic field spaces under the action of magnetic force when the fluid flows through the fluid separation sieve; and when the magnetic poles relatively move along the direction of the nonmagnetic wires, the magnetic particles are acted by the magnetic force of the magnetic poles, move with the magnetic poles along a direction nearly orthogonal to a fluid flow channel, and are separated out. The magnetic fluid sieving device of the invention has the advantages of realization of continuous and efficient separation of the magnetic particles from the fluid, low operation energy consumption, and simple maintenance, and can be used for environmental protection, magnetic metal recovery, and magnetic mineral sorting.

The invention provides a cobalt-containing composite absorbing material and a preparation method thereof. The composite absorbing material comprises a graphene oxide matrix, ferrite, nanometer cobaltand cobaltous carbonate, and the ferrite, the nanometer cobalt and the cobaltous carbonate are loaded on the surface of the graphene oxide matrix. Results of the embodiment show that according to theobtained composite absorbing material, when the matching thickness is 2.44 mm, the maximum absorption -19.13dB is achieved during 12.32 GHz, and the effective absorption frequency band whose reflection loss is lower than -10dB reaches 4.10 GHz; and when the matching thickness is 2.40 mm, the maximum absorption -17.36dB is achieved during 13.34 GHz, the effective absorption frequency band whose reflection loss is lower than -10dB reaches 2.74 GHz, the visible absorbing frequency band is substantially widened, and the absorbing capability is enhanced.

The invention belongs to the technical field of ferrites, and particularly relates to a ferrite magnetic material which comprises main components, auxiliary components and additives, the main components comprise Fe2O3, Mo2O3, Yb2O3, NiO and ZnO, and the auxiliary components comprise WO3 and Nd2O3. Based on the main component amount, the content of Fe2O3 in the main components is 48-52 mol%, the content of Mo2O3 in the main components is 16-24 mol%, the content of Yb2O3 in the main components is 12-20 mol%, the content of NiO in the main components is 9-15 mol%, and the content of ZnO in the main components is 6-10 mol%. Based on the weight of the main components, the content of WO3 is 0.1-1wt%, and the content of Nd2O3 is 0.1-1wt%. The additives are composed of V2O5, SiO2 and CuO. The ferrite material disclosed by the invention has higher magnetic conductivity and lower magnetic loss at the same time under 13.56 MHz, and meets the application requirements of NFC.

The invention discloses an epoxy resin glass fiber composite isolation protection material which is prepared from the following raw materials in parts by weight: 100-150 parts of epoxy resin, 10-15 parts of glass fiber, 10-20 parts of a polyaniline-silicon carbide compound, 35-50 parts of an inorganic flame retardant, 5-10 parts of nano calcium carbonate, 20-55 parts of a rare earth coupling agent and 5-10 parts of a dispersing agent. The inorganic flame retardant is composed of magnesium hydroxide and calcium hydroxide. The invention also discloses an application of the epoxy resin glass fiber composite isolation protection material in isolation protection of a relay protection wiring terminal. The epoxy resin glass fiber composite isolation protection material has good moisture resistance, flame retardance and wave-absorbing anti-interference performance, isolation protection can be better carried out on a wiring terminal, and the safety is improved.

The invention relates to a preparation method of glass ceramic with good thermal conductivity, and belongs to the technical field of glass ceramic materials. According to the invention, waste glass powder and silicon dioxide are used as raw materials, alumina fiber toughening-modified epoxy resin is used as a binder, and aluminum nitride, diamond, copper powder and waste ceramic powder with high thermal conductivity are used as fillers, and the glass ceramic with good thermal conductivity is prepared by doping rare earth lanthanum oxide through low-temperature co-firing. The diamond has high thermal conductivity, low dielectric constant, high resistivity and high breakdown field intensity; the aluminum nitride has excellent electrical properties and thermal properties, is a good thermal shock resistant material, has strong molten metal erosion resistance, is also an electrical insulator, and has good dielectric properties. By means of the low-temperature co-firing process, the preparation method is low in sintering temperature, low in dielectric constant and short in signal delay time; the glass serves as a fluxing agent to promote densification of the glass-ceramic composite material; in addition, the ceramic filler is used for improving the mechanical strength and insulativity of the substrate and preventing warping caused by the surface tension of the glass during sintering.

The invention provides a nickel-containing composite absorbing material and a preparation method thereof. The composite absorbing material comprises graphene oxide substrate, ferrite, nano nickel andnickelous carbonate; the ferrite, the nano nickel and the nickelous carbonate are loaded on the surface of the graphene oxide substrate. The result of the embodiment reveals that when the matching thickness of the composite absorbing material is 2.25 mm, -15.16 dB is absorbed to the maximum when the frequency reaches 14.88 GHz, the effective absorbing frequency band reaches 4 GHz when the reflection loss is lower than -10 dB, the absorbing frequency band is significantly broadened, and the absorbing capability is enhanced.

The invention discloses a metal-carbon composite particle and a preparation method and application thereof. The preparation method of the metal-carbon composite particles comprises the following steps: 1) dispersing cobalt salt or/and nickel salt and trimesic acid in a solvent, and reacting to obtain cobalt or/and nickel-based MOF (Metal Organic Framework); and 2) calcining the cobalt or/and nickel-based MOF in a protective atmosphere to obtain the metal-carbon composite particles. The metal-carbon composite particle has the advantages of excellent microwave absorption performance, wide absorption bandwidth, good impedance matching performance, light weight and simple preparation method, can be used in electromagnetic wave absorption materials, and has a very wide application prospect.

The invention provides a SrNdMnO wave-absorbing material and a preparation method thereof, and relates to the technical field of microwave absorbing materials. The molecular formula of the SrNdMnO wave-absorbing material is Sr1-xNdxMnO3, x is more than 0 and less than or equal to 0.2, and the wave-absorbing material is obtained by adopting gelation reaction, pre-sintering and calcining. The invention overcomes the defects in the prior art, and the wave-absorbing material can absorb electromagnetic waves in the microwave band of 2-18GHz, and has the advantages of wide absorption frequency band, high absorption efficiency (greater than 90%), low absorption frequency, simple preparation process and suitability for large-scale production.

The invention relates to a production method of an electromagnetic wave-absorbing gypsum composite material, and belongs to the technical field of wave-absorbing materials. According to the productionmethod of the electromagnetic wave-absorbing gypsum composite material, antimonous oxide and carbon fibers are mechanically mixed, rare earth is adopted for doping to modify an obtained mixture, an obtained modified mixture is used as filler, through a sol-gel method, ferrous titanate is produced, and is used as an absorbent, gypsum is used as a matrix, and the matrix and the absorbent are subjected to composition to produce the electromagnetic wave-absorbing gypsum composite material; the antimonous oxide not only has wave transmittance, but also has certain absorbing capability, after rareearth doping modification is conducted, the magnetic performance and the wave absorbing performance are effectively improved, the ferrous titanate is an inorganic functional material with microwave absorbing performance, and has good wave absorbing performance, and the carbon fibers can effectively improve the mechanical performance of the material; and an ilmenite structure has a large electricalloss tangent angle, by means of electronic polarization, ionic polarization, molecular polarization or interfacial polarization of a medium, electromagnetic waves are attenuated and absorbed, and theferrous titanate compound has an excellent impedance matching property.