776 results about "Remanence" patented technology

The present invention relates to a magnet powder formula of hexagonal type magnetoplumbite permanent magnetic ferrite, sintered magnet and method of producing the same. The invention provides a sintered permanent magnetic ferrite and magnet powder capable of acquiring remanence of more than 4500 Gs and Intrinsic coercivity of more than 5000 Oe at the same time, pointing to problems of unable to acquire high magnetic property and high Intrinsic coercivity at the same time in prior technology, and method of producing the same. major formula of the invention is a permanent magnetic ferrite powder containing hexagonal type magnetoplumbite permanent magnetic ferrite of the following formula as main phase: A[1-x-y]Ca[x]R[y]Fe[2n-z]M[z]O[19], A represents Sr or Sr and Ba, R represents at least one of La, Pr, Nd or Bi, and La is needed; M represents at least one of Co, Ni and Zn, and Co is needed; x, y, z represents addition percentage of each main metal elements.

An alloy of Fe_{100-a-b-c-d-x-y-z}Cu_aNb_bM_cT_dSi_xB_yZ_z and up to 1 atomic % impurities; M is one or more of Mo or Ta, T is one or more of V, Cr, Co or Ni and Z is one or more of C, P or Ge, wherein 0.0 atomic % a <1.5 atomic %, 0.0 atomic % b <3.0 atomic %, 0.2 atomic % c 4.0 atomic %, 0.0 atomic % d <5.0 atomic %, 12.0 atomic %<x<18.0 atomic %, 5.0 atomic %<y<12.0 atomic % and 0.0 atomic % z<2.0 atomic %, and wherein 2.0 atomic % (b+c) 4.0 atomic %, produced in the form of a strip and having a nanocrystalline structure in which at least 50% by volume of the grains have an average size of less than 100 nm, a remanence ratio J_r/J_s<0.02, J_r being the remanent polarisation and J_s being the saturation polarisation, and a coercitive field strength H_c which is less than 1% of the anisotropic field strength H_a and/or less than 10 A/m.

The invention relates to a weak magnetism detecting instrument based on time-resolved remanence relaxation detection and application thereof. The detecting instrument consists of a detecting unit provided with a sensitive element with high sensitivity therein, a sample bracket, a pulse magnetic field generator, a signal data acquiring and converting system and a computer. The working principle of the detecting instrument is that the superparamagnetic nanomaterial is magnetized via pulse by means of a pulse magnetic field with a steep edge, then a magnetism sensitive element with a high sensitivity is utilized to carry out track analysis on the remanence relaxation generated by the superparamagnetic nanomaterial under the action of the pulse magnetic field, and then a quantitative detection of superparamagnetic nanomaterial is realized. By means of the instrument, biological analysis with high sensitivity can be realized by combining with nano-particles or magnetic beads. The instrument and method of the invention have fast detection speed, low cost, high sensitivity and good stability, and are suitable for fields of biological analysis, disease diagnosis, food security, environment monitoring and the like.

The invention discloses a sintered Nd-Fe-B permanent-magnet material and a preparation method thereof. The molecular formula of the sintered Nd-Fe-B permanent-magnet material is (NdPr)aFe[100%-a-b-c]BbMc, wherein M is one or a plurality of Dy, Ho, Nb, Zr, Co, Ga, Al and Cu; a, b and c represent the mass percentages of the corresponding elements; a is greater than or equal to 20% and smaller than or equal to 32%, b is greater than or equal to 0.9% and smaller than or equal to 1.2%, and c is greater than or equal to 0% and smaller than or equal to 6%; and the mass of the element Pr accounts for 20-49% of the mass of PrNd alloy. Compared with the prior art, the sintered Nd-Fe-B permanent-magnet material has the following advantage: the content of the element Pr in the Nd-Fe-B permanent-magnet material is increased by adjusting the composition and content of the Nd-Fe-B permanent-magnet material, so that the mass percentage of the element Pr in the light rare earth Nd is increased to 20-49%. Compared with the prior Nd-Fe-B permanent-magnet material, the Nd-Fe-B permanent-magnet material obtained by the invention has the advantages that the high coercive force can be maintained and simultaneously the cost is greatly lowered without reducing the remanence.

The invention discloses current transformer remanence measurement system and method. An upper computer receives current transformer data signals transmitted by a data unit. Related data processing is performed to calculate remanence coefficient. Operation states of an operating unit are automatically judged during measurement, and on and off of a relay are controlled. When the primary side of a current transformer is open, the secondary side is sequentially subjected to positive charging, discharging and revere charging until the current transformer is saturated. Flux variations in positive charging process, discharging process and revere charging process are obtained by calculation. The three flux variations are then calculated to obtain accurate remanence coefficient. Therefore, errors in remanence coefficient measurement caused when initial core flux of the current transformer is not zero are eliminated, accuracy in remanence coefficient measurement for the current transformer is increased, and fairness in electric energy measurement and trade settlement for the current transformer is guaranteed. The current transformer remanence measurement system and method have promising application prospect.

Disclosed are a rare earth permanent magnet and a preparation method. The preparation method of the rare earth permanent magnet is capable of improving coercivity of the magnet while keeping binding strength of a base body and a plated layer or coated layer after plating or coating on the basis without reducing remanence and magnetic energy product of the magnet and includes: firstly dissolving powder of fluoride containing R2, nitrate containing R3 and phosphate containing R4 into water or alcohol to prepare solution; uniformly applying the solution on the surface of a magnet to be treated; then dewatering or performing alcohol treatment on the magnet to be treated; finally, enabling the magnet to be treated to be subjected to diffusion heat treatment to obtain the treated magnet. By the aid of the preparation method, uniformity of the powder on the surface of the magnet can be improved, powder residues on the surface of the magnet after heat diffusion are reduced, the coercivity of the magnet is improved, and the binding strength of the magnet of the base body and the plated layer or coated layer after plating or coating is kept constant.

The invention discloses a transformer remanence detection and demagnetization method which comprises the following steps: collecting residual flux content of a test transformer, and inputting the residual flux content into an intelligent analysis system; reading the residual flux content of the test transformer through a human-computer interaction interface, and inputting corresponding control instructions; controlling the output of a frequency conversion voltage-regulating unit through the control instructions; and outputting by the frequency conversion voltage-regulating unit a low-frequency AC voltage required for demagnetization, and carrying out demagnetization on the test transformer. The invention also discloses a transformer remanence detection and demagnetization device which comprises an AC power supply module, a power supply conversion module, a DC power supply module, a control acquisition module, the frequency conversion voltage-regulating unit, a man-machine interaction unit, a data acquisition module, the intelligent analysis system and the test transformer. The low-frequency AC voltage is utilized for demagnetization, thereby reducing power capacity and size of the demagnetization device; and through the man-machine interaction unit, operation personnel can obtain the demagnetization processing progress accurately and visually, and input the corresponding control instructions, thereby realizing thorough demagnetization of the test transformer.

The invention discloses a method for preparing a sintered samarium-cobalt magnet. The method comprises the following steps of: preparing a first samarium-cobalt alloy and a second samarium-cobalt alloy; performing primary crushing on the first samarium-cobalt alloy and the second samarium-cobalt alloy; mixing first samarium-cobalt alloy primarily crushed magnetic powder and second samarium-cobalt alloy primarily crushed magnetic powder, and performing fine crushing, so that primarily crushed mixed magnetic powder is refined, and components are homogenized; and performing magnetic field orientation forming, cold isostatic pressing, sintering, solid solution treatment and ageing treatment on samarium-cobalt magnetic powder obtained by fine crushing in sequence. The method has the advantages that the first samarium-cobalt alloy has high remanence component characteristic, the second samarium-cobalt alloy has high coercivity component characteristic, the sintered samarium-cobalt magnets with various magnetic properties can be obtained by adjusting the mixing ratio of the first samarium-cobalt alloy primarily crushed magnetic powder to the second samarium-cobalt alloy primarily crushed magnetic powder, and the process is stable and low in cost.

The invention belongs to the permanent-magnet material field and provides a method for preparing permanent magnet oxysome material, which mainly comprises a novel technique adopted in wet ball-milling stage, that is, being receiving wet ball-milling to reach a certain granularity, a pre-sintering material firstly receives low-temperature resintering, and then receives wet remilling for a short time, so as to prepare needed slurry for facilitating sintering after forming. Through adopting the method provided by the invention, the sample coercitive force is effectively upgraded to obtain excellent comprehensive magnetic property on the basis that magnetic remanence is not reduced.

The invention provides a heavy rear earth adhering method of a sintered NdFeB magnet, and belongs to the technical field of rear earth magnetic functional materials and preparation. The preparation technology particularly includes the steps that the sintered NdFeB magnet after surface pretreatment is placed in a heavy rear earth salt organic solution, under the action of currents, heavy rear earth elements are deposited on the surface of the sintered NdFeB magnet and form a dense heavy rear earth metal thin layer, and then the heavy rear earth elements in a heavy rear earth metal film diffuse into the magnet through grain boundaries in the process of high temperature diffusion treatment or high temperature diffusion and low temperature tempering two-stage thermal treatment. Coercivity of a sintered NdFeB rear earth permanent magnetic material prepared through the method is remarkably improved, remanence is not obviously reduced, heavy rear earth consumption is small, the process is simple and controllable, efficiency is high, and the method is suitable for industrial production.

A functional block for assembly includes at least one element and a magnetic film attached to the element and having a magnetic remanence (M_R/M_S) of less than about 0.2, having a coercive field (H_c) of less than about 100 Oersteds (100 Oe) and having a permeability (μ) of greater than about two (2). At least one element is selected from the group consisting of a semiconductor device, a passive element, a photonic bandgap element, a luminescent material, a sensor, a micro-electrical mechanical system (MEMS), an energy harvesting device and combinations thereof. An article for assembly includes a substrate and a patterned magnetic film disposed on the substrate and defining at least one receptor site. The patterned magnetic film is magnetized primarily in a longitudinal direction and is characterized by a BH product of greater than about 1 megaGauss Oe.

A motor includes poles P having a remanence Mr of 0.9 T or more, a coercivity HcJ of 0.80 MA/m or more, and a maximum energy product (BH)_max of 150 kJ/m³ or more, which sets a center point Pc of the magnetic poles in a circumferential direction on a rotor outer circumferential surface to a maximum thickness t_max, wherein when a line connecting the Pc and a rotational axis center Rc is Pc-Rc, a straight line connecting an arbitrary point Px in the circumferential direction on the rotor outer circumferential surface and the Rc is Px-Rc, an apex angle of the lines Pc-Rc and Px-Rc is θ, a number of pole pairs is Pn, a circumferential direction magnetic pole end is Pe, and a magnetic pole end biasing distance ΔL_Pe of the circumferential direction magnetic pole ends Pe is α×t_max (α is a coefficient).

The invention discloses a neodymium iron boron magnet, a preparation method and a device applying the same, belonging to the field of magnetic materials. The magnet comprises the following components in percentage by weight according to the general formula: 27 to 35 percent of R representing one or two rare-earth elements except Gd, 0.55 to 2 percent of Gd, 0.5 to 3.5 percent of Co, 0.05 to 0.5 percent of M1 representing one transition metal element such as Cu, Al or Ge, 0 to 0.5 percent of M2 being one or two transition metal elements except Co and M1, 0.9 to 1.2 percent of B (namely boron) and the balance of Fe and unavoidable impurities. The neodymium iron boron magnet disclosed by the invention is compounded with Gd, Co, M1 and M2, thus the reversible magnetic induction temperature coefficient alpha and the coercive force temperature coefficient beta are better improved, the coercive force of the magnet is greatly improved while the magnetic energy product and residual magnetism are guaranteed not to reduce, the heavy rare earth element Gd is effectively utilized, and the performance is improved while the manufacturing cost is well saved.

The present invention is Mn-Zn ferrite with high magnetic permeability in wide temperature range and its preparation process. The Mn-Zn ferrite consists of main components including Fe2O3 51-56 mol%, MnO 34-40 mol% and ZnO 6-12 mol%, and supplementary components. The Mn-Zn ferrite has relatively high initial magnetic permeability, power consumption difference lower than 70 kW/cu m in the temperature range of 25-120 deg.c at 100 KHz and 200 mT, minimum power consumption below 350 kW/cu m in the said temperature range, remanence below 85 mT at Hú¢1194 A/m and 25 deg.c, and excellent DC superposition characteristic.

The invention relates to a security element for protecting documents of value, which has magnetic material. Furthermore, the invention relates to a document of value, a transfer material and method for producing such security elements and documents of value as well as a method and an apparatus for checking such a security element or document of value. According to the invention the security element has at least two magnetic materials, wherein the magnetic materials have different coercive field strengths and are applied onto and/or incorporated in the security element in such a manner that their remanence is equally high.

The invention aims to provide a method for measuring a parameter of magnetic characteristic of a permanent magnet, which adopts a data compression algorithm to carry out characteristic point extraction, redundant data deletion and data storage reduction on a magnetic strength value acquired from the outside of the permanent magnet. The spatial magnetic strength value outside the permanent magnet can be acquired through a magnetic field measurement system; the characteristic point is extracted by the data compression algorithm; a three-dimensional finite element model of the permanent magnet is established; remanence and coercive force are initially set; an emulation value of the magnetic strength of the characteristic point is obtained through emulation calculation; the remanence and the coercive force are constantly corrected by comparing the emulation value with a measured value until the difference of the emulation value and the measured value is smaller than a certain error range, thereby obtaining the remanence and the coercive force of the permanent magnet. The whole flow is realized through a software system. The invention provides a method for measuring the parameter of the aged magnetic characteristic, and has the characteristics of high automation degree and strong flexibility.

The invention discloses a measuring device for a hysteresis loop made of a ferromagnetic material and an application method of the measuring device. The measuring device for the hysteresis loop made of the ferromagnetic material comprises an excitation circuit, a control circuit, an integrating circuit, a sampling resistor circuit, a liquid crystal display circuit, a key detecting circuit and an oscilloscope. According to the method, step values of excitation voltage and excitation resistance are set through programming a singlechip; the oscilloscope displays the hysteresis loop to be measured; and an upper computer measures and analyzes the coercivity, the remanence induction strength, the maximum field, the maximum magnetic induction strength and the magnetic hysteresis loss of the ferromagnetic material according to the hysteresis loop. The original mechanical switch and manual knob type switch control mode is replaced by a program control mode, and shortcomings that contacts of a knob switch are in a poor contact state easily, gears are easy to loosen, and the like are overcome. By an experimental instrument developed in the invention, the reliability of experimental equipment can be increased, and the service life of the experimental equipment can be prolonged. Owing to the program control mode, the step values of the excitation voltage are low, gears of the excitation voltage are sufficient, measurement precision is high, and practicality and accuracy are good.

The invention provides a sintered Nd base magnet which is free of a decline of remanence, has a high coercive force, especially at the edges thereof, is unsusceptible to demagnetization even at high temperature, and is suited for use in permanent magnet rotary machines.

The invention discloses a preparation method of a rare-earth permanent magnet, a preparation device and a rare-earth permanent magnet prepared thereby, and relates to the preparation technology of sintered rare-earth permanent magnet with high coercivity. The invention is characterized in that the preparation method is carried out in two-chamber vacuum equipment which can be communicated with each other and also can carry out pressure increasing and decreasing treatment and heating treatment, and comprises the following steps of: firstly putting an evaporation material in a first chamber for crushing; putting a treated piece in a second chamber, vacuumizing the second chamber and enabling the vacuum degree of the second chamber to be equivalent to that of the first chamber; transferring the treated piece into the first chamber and carrying out heat diffusion treatment in the first chamber; carrying out pressure decreasing on the first chamber, and enabling the vacuum degree of the first chamber to be equivalent to that the second chamber; and transferring the treated piece back into the second chamber, and carrying out aging treatment in the second chamber. The preparation method disclosed by the invention has the advantages that no powder is remained on the surface of the magnet; the metal powder is adopted for evaporation, so that the evaporation efficiency is greatly increased, and the purpose of providing high-coercivity and high-remanence magnet by using fewer heavy rare-earth materials can be realized; and simultaneously, the magnet has stronger corrosion resistance.

The invention relates a double-permanent magnet outer-rotor permanent magnet biased radial magnetic bearing comprising outer magnetic conductive rings, outer permanent magnets, stator cores, excitation windings, inner magnetic conductive rings, inner permanent magnets and rotor cores, wherein four magnetic poles consist of each stator core, eight magnetic poles of the left end and the right end of the magnetic bearing consist of two stator cores, and magnetic poles in the positive and the negative directions of an X axis and a Y axis respectively consist of the eight magnetic poles; each stator magnetic pole is wound with the excitation winding; the rotor cores are positioned outside the stator cores; the outer magnetic conductive rings are positioned outside the rotor cores; the outer permanent magnets are positioned among the outer magnetic conductive rings; the outer magnetic conductive rings are connected with the rotor cores; certain gaps are retained on the inner surfaces of the rotor cores and the outer surfaces of the stator cores to form air gaps; and the permanent magnets are positioned among the inner magnetic conductive rings. The invention solves the problem of large remanence moment of the traditional permanent magnet biased outer-rotor radial magnetic bearing for space.