74 results about "Ferromagnetic particle" patented technology

The invention provides an oil aliasing particle detection device based on a multi-frequency eddy current effect, which adopts a multi-mode electromagnetic sensing architecture, integrates three groups of orthogonally arranged solenoid coil detection units in a single detection channel, and respectively loads low-frequency (10-100kHz), intermediate-frequency (100kHz-1MHz) and high-frequency (1-10MHz) excitation signals with different characteristics, so as to detect the aliasing particles in the oil. Based on frequency domain response characteristic differences presented by different metal particles in high, medium and low frequency eddy current fields, a particle material-size-space distribution frequency domain characteristic matrix is constructed through multi-physics field coupling modeling, and synchronous identification and orthogonal decoupling of ferromagnetic particles and non-ferromagnetic particles are realized. According to the invention, the eddy current effect difference characteristics of metal / non-metal particles under excitation of different frequencies are utilized, and a signal decoupling algorithm is combined to realize accurate distinguishing of aliasing particles, so that the reliability of high-flux oil detection is remarkably improved; and a key technical support is provided for engineering application of a microfluid chip technology in the fields of engine wear monitoring, hydraulic system fault early warning and the like.

The invention discloses a water-rich broken surrounding rock directional grouting method based on an external magnetic field. The method comprises the following steps that 1, geological exploration is conducted on a target water-rich broken surrounding rock area; step 2, mixing the base material, the nano ferroferric oxide magnetic particles, the rheology regulating agent, the dispersing agent and the coagulation accelerator according to a mass ratio; 3, injecting alternating current with the frequency of 50-500Hz into the electromagnetic coil to generate a rotating magnetic field with the intensity of 3-10kA / m, and driving the slurry to directionally migrate along the main fracture area; 4, the grouting pressure of the pre-buried pressure sensor is monitored in real time, when the pressure change rate delta P / delta t is larger than or equal to 0.1 MPa / min, the electromagnetic coil injection frequency is switched to alternating current of 1 kHz to 10 kHz, so that the intensity of a magnetic field is improved to 8 kA / m to 15 kA / m, and grouting on the micro-crack area is enhanced; and 5, when the pressure change rate delta P / delta t is smaller than + / -0.1 MPa / min and lasts for 5-10 min, grouting operation is ended. The method aims at solving the problems that in grouting reinforcement of the water-rich fractured stratum, slurry is lost along with water flow, micro-cracks are difficult to fill, and reinforcement bodies are distributed unevenly.

The invention discloses a high dynamic response electromagnetic damping system, and relates to the technical field of dampers. Through cooperation of the sealing driving electromagnet and the resettable tension spring, instantaneous opening and closing of the circulation path of the inner cylinder and the outer cylinder are achieved; the two working modes of gear damping and stepless damping are switched, only the electromagnet needs to be cut off or excited, a valve element does not need to be mechanically inserted and pulled, the dynamic response time can be compressed to the millisecond level, and the high-frequency vibration suppression capacity and the system reliability are greatly improved; a blade-worm gear-motor closed-loop servo structure is adopted, a force sensitive resistor senses the direction and the size of oil flow in real time, and the rotating speed of the blade can be continuously adjusted within the resistance coefficient of 0-100% through a control algorithm; compared with a magnetorheological fluid type scheme depending on magnetic induction shearing, the problems of temperature drift and ferromagnetic particle deposition are solved, and the damping linearity and repeatability are ensured.

A pressure sensing conductive elastomeric composite material, the material comprising a polymer matrix, itself comprising an elastomeric material, and a conduction network within the polymer matrix. The conduction network comprises: a plurality of particle chains, with each particle chain comprising a plurality of metallic ferromagnetic particles, a plurality of liquid metal droplets, and a plurality of non-ferromagnetic conductive platelets, wherein the conductivity of the composite material varies as a function of the pressure applied to the material.

An apparatus and a polishing system for rotational magnetorheological abrasive flow nano-finishing are described. The apparatus includes an upper cylinder with coupled upper piston and a lower cylinder with coupled lower piston. A first motor drives synchronized reciprocating motion of both pistons via respective slider crank mechanisms. A magnet fixture positioned between the cylinders includes permanent magnets arranged in a ring configuration with a central hole for workpiece placement. A second motor rotates the magnet fixture to manipulate magnetic field orientation. The cylinders, pistons and magnet fixture define a space for containing magnetorheological (MR) fluid including ferromagnetic particles, abrasive particles and carrier fluid. The configuration enables controlled fluid flow through the hole while maintaining direct workpiece contact, with ferromagnetic particles exhibiting both rotational and reciprocal movement patterns. This dual-motion finishing approach enables material removal through magnetic field-controlled abrasive action, achieving nano-scale surface quality on complex geometries.

A shaped structure having a fixed ferromagnetic polymer material aligned to a unified alignment direction. The shaped structure may include ferromagnetic particles suspended in the fixed ferromagnetic polymer material, and the ferromagnetic particles are aligned to the unified alignment direction. A method of manufacturing a structure includes forming ferromagnetic polymer precursors, dispensing the ferromagnetic precursors into a shaped structure, applying a magnetic field to cause the ferromagnetic precursors to align to a unified crystallographic orientation, and finishing the shaped structure to form a ferromagnetic polymer with a fixed unified crystallographic orientation and produce the structure.

The invention belongs to the technical field of microbial protection and functional metal coating preparation, and particularly relates to a preparation method of a metal-based graphene oxide and zirconium oxide composite antibacterial coating on a flexible metal foil through magnetic field assisted jet electrodeposition. According to the method, a metal ion electroplating solution containing graphene oxide and zirconium oxide serves as a raw material on a flexible metal substrate, ferromagnetic particles are introduced to serve as a carrier, one-time forming is carried out under the action of a magnetic field through the scanning jet electrodeposition technology, and efficient fixing and uniform distribution of graphene oxide and zirconium oxide in a metal coating are achieved. The prepared coating is compact in structure and high in binding force, after the coating is in contact culture with escherichia coli and staphylococcus aureus for half an hour, the antibacterial rate reaches 94% or above, the antibacterial rate reaches 97% or above, and the coating has excellent stability and reliability. The method disclosed by the invention is simple and convenient in process and high in adaptability, can form a high-performance antibacterial coating on a flexible substrate, is suitable for the antifouling and anticorrosion fields of public health facilities, marine protection and engineering equipment, and has a wide industrial application prospect.

The invention relates to an in-situ ferromagnetic wear particle detection sensor and a detection method, the in-situ ferromagnetic wear particle detection sensor comprises an LC oscillation circuit, an inductance digital converter and a microcontroller, the LC oscillation circuit comprises an induction coil and a first capacitor connected with the induction coil; the detection sensor further comprises a permanent magnet, the induction coil is arranged on one side of the permanent magnet, and when ferromagnetic particles enter the induction coil under the adsorption action of the permanent magnet, inductance change of the induction coil and equivalent parallel resistance change of the induction coil and the particles are caused. The inductance digital converter is used for receiving inductance data and equivalent parallel resistance data output by the LC oscillating circuit, converting the inductance data and the equivalent parallel resistance data into resonant frequency and proximity and outputting the resonant frequency and the proximity, and the microcontroller is used for receiving the resonant frequency and the proximity data, processing the resonant frequency and the proximity data and outputting the processed data outwards. The system has high detection sensitivity, can distinguish particle characteristics, feeds back a machine operation state in real time, and is convenient for operators to maintain the machine in time.

The utility model relates to the field of air purification, in particular to an air purification device for a subway station based on electromagnetic adsorption, which comprises a reverse fan unit, a coarse filter unit and an electromagnetic filter unit, and the electromagnetic filter unit is arranged between the reverse fan unit and the coarse filter unit. The electromagnetic filter unit comprises a filter element and a coil, the filter element comprises a filter element framework and a filter screen, and the filter screen is made of a soft magnetic material. According to the utility model, the electromagnetic filter unit is arranged, the electromagnetic effect principle is utilized, and the coil is electrified, so that a high-gradient magnetic field is generated in the filter element, and ferromagnetic particles in the air are adsorbed by the filter element, so that high-concentration iron-containing particles in the air in the subway station can be removed in a targeted manner, and the subway air quality is remarkably improved; and the body health of passengers and subway workers is protected.

The utility model discloses an aviation lubricating oil supply device, and belongs to the technical field of lubricating oil supply. An aviation lubricating oil supply device comprises a filter box and further comprises a mounting plate detachably arranged on the filter box, outer pipes distributed in an array mode are detachably arranged at the bottom of the mounting plate, a connecting plate is detachably arranged at the top of the mounting plate, a positioning column is arranged in the connecting plate, and a strong magnet of a rotary body columnar structure is fixedly arranged at the bottom of the positioning column. The outer wall of the strong magnet abuts against the inner wall of the outer pipe. The outer pipe made of the non-magnetic material is arranged on the mounting plate, the strong magnet is arranged in the outer pipe, ferromagnetic particles in lubricating oil can be adsorbed on the outer pipe, during cleaning, after the mounting plate is detached from the filter box, the strong magnet is pulled out of the outer pipe through the connecting plate, at the moment, the outer pipe loses magnetism, and the ferromagnetic particles in the lubricating oil can be cleaned. Under cleaning of water flow or wind power, ferromagnetic particles on the outer wall of the outer pipe can be quickly cleaned, and the using effect is improved.

The present invention proposes an atomizer containing stem cell exosomes, and a preparation method and application thereof, which belong to the field of exosome technology. Magnetic ferroferric oxide particles are prepared, the surface of which is modified with tannic acid, loaded with berberine and doxorubicin, and then mixed and incubated with exosomes secreted by adipose mesenchymal stem cells, centrifuged, added to physiological saline, and ultrasonically dispersed uniformly to obtain an atomizer containing stem cell exosomes. The atomizer containing stem cell exosomes prepared by the present invention not only has a simple preparation method and a wide source of raw materials, but the prepared atomizer is administered by spraying and directly enters the lungs. It has the unique performance of magnetic targeted drug delivery, releases drugs in a targeted and fixed-point manner, improves the efficacy of the drug, and effectively promotes tumor cell apoptosis, and plays an anti-lung cancer and anti-pneumonia role.

A power inductor includes a coil and an induced magnetic element. The coil includes two outer loop circuit layers and a plurality of insulation spacing layer. The outer loop circuit layers are stacked up and electrically connected to each other. The outer loop circuit layers have an outer connection end apiece. At least one insulation spacing layer is located between the outer loop circuit layers. The induced magnetic element encapsulates the coil and exposes the outer connection end of each of the outer loop circuit layers. The induced magnetic element includes a plurality of ferromagnetic particles. The ferromagnetic particles include an iron-based alloy particle and an insulation film covering the iron-based alloy particle apiece.

This invention provides a method and system for recycling fluororubber waste, belonging to the field of rubber recycling. The method includes a pre-cooling step, cooling the fluororubber waste; a low-temperature cryogenic crushing step, using a liquid refrigerant to perform a secondary cooling and freezing of the pre-cooled fluororubber waste, and then cryogenically crushing the secondary-cooled fluororubber waste, with the gas from the vaporization of the liquid refrigerant provided to the pre-cooling step for recovering cold energy; a washing step, washing the fluororubber waste during the cryogenic crushing process to remove additive powders; and a magnetic separation step, using a high-gradient magnetic field to remove ferromagnetic particles generated during the cryogenic crushing process from the washed fluororubber waste, obtaining recovered fluororubber particles. Through the processing scheme of this application, the recovered product particles are uniform in size and have few impurities, meeting the quality requirements for fluororubber reuse.

The application discloses a magnetic accessory replaceable particle medium limb rehabilitation training device and belongs to the field of rehabilitation training instruments. The device solves the problems of single resistance direction, complicated adjustment, lack of quantitative feedback and secondary injury of existing hand and ankle training devices. The device comprises a container, the container is filled with ferromagnetic particles, the outer side wall and the bottom are provided with magnetic accessories with different magnetic force gears which can be replaced, the inner side wall and the bottom surface are provided with a pressure sensing module and are in communication connection with a data display transmission module. The device adjusts the particle resistance through the magnetic accessories, provides full-directional diffuse resistance, realizes passive fast multi-stage resistance adjustment, simultaneously collects pressure distribution data in real time, identifies abnormal force mode and gives an early warning, can quantitatively evaluate the training effect and covers hand and ankle rehabilitation training.

The utility model discloses a stainless steel explosion-proof magnetic drive pump which comprises a driving motor, the side edge of the driving motor is connected with a supporting frame through a bolt, one side of the supporting frame is fixedly connected with a pump body through a bolt, the side edge of the pump body is fixedly connected with a flow guiding device through a bolt, and the interior of the flow guiding device is fixedly connected with a filtering assembly through a bolt. According to the scheme, the impeller rotates, the magnetic pole of the side, close to the first magnet ring, of the second magnet ring is the same as that of the first magnet ring, and the like poles repel each other, so that the stability of the impeller during operation is kept, noise generated during operation is reduced, and the service life of the magnetic drive pump is prolonged; liquid enters the pump shell from the flow guide pipe at the other end of the fixed box, the liquid entering the magnetic drive pump is filtered, blockage in the magnetic drive pump is avoided, and meanwhile it is avoided that ferromagnetic particles are adsorbed into the magnetic drive pump, and operation of the magnetic drive pump is affected.

Filter unit (5) for filtering a fluid in a hydraulic system, in particular for a coupling system (2), with a housing (10) for arrangement in the hydraulic system, wherein the housing has a flow section (15) for guiding the fluid along a defined flow path (S) through the filter unit (5), with a magnet (9) for separating ferromagnetic particles from the fluid, wherein the magnet is arranged inside the housing (10), wherein the magnet (9) is designed as a ring magnet (16), wherein the flow path (S) runs through a central opening (23) of the ring magnet (16), wherein a circumferential recess (17) is provided in an inner circumference of the housing (10), wherein the ring magnet (16) is recessed in the recess (17), characterized in that the recess (17) is designed as a stepped annular groove, wherein a receiving area (19) for receiving the magnet (16) is formed by a first step of the stepped annular groove, and a trapping area (18a) for forming a trap for the ferromagnetic particles is formed by a second step of the stepped annular groove, and in that a further trapping area (18b) is formed by a third step, wherein the receiving area (19) is axially located between the two Trap areas (18a,b) is arranged such that the ring magnet (16) is spaced apart from the housing (10) on both sides by means of an annular gap in sections.

The invention provides a multi-particle-size particle damping device based on double cavities and electromagnetic regulation and control. The multi-particle-size particle damping device comprises a damping shell; the damping shell is divided into a first chamber and a second chamber which are independent from each other through an insulating partition plate, and particles with different particle sizes are arranged in the first chamber and the second chamber respectively; an electromagnet is arranged at the end part of each cavity, and an electromagnet coil is wound on the periphery of each electromagnet; a current coil is arranged on the outer side of each cavity in a surrounding mode. According to the device, the two independent cavities are arranged to contain ferromagnetic particles with different particle sizes respectively, intelligent release and excitation of the particles are achieved through electromagnetic control, and therefore self-adaption and low-energy-consumption suppression of broadband vibration is achieved, the vibration reduction efficiency and reliability are remarkably improved, and the application range of the device is widened. Through the device, the problems of narrow vibration reduction frequency band, incapability of adapting to frequency change, high energy consumption and the like in the prior art are solved.

The invention belongs to the technical field of aero-engines, particularly relates to an oil abrasive particle detection device and method for a fuel oil system of a marine gas turbine, and aims to solve the problems of insufficient abrasive particle detection information and easy secondary pollution in the prior art. The device comprises a backwashing system and an abrasive particle separation and detection system, wherein the backwashing system realizes deep cleaning of a filter element through an ultrasonic massage box and a heat exchanger, and prevents secondary pollution of particles at wrinkles by adopting silicone oil paper; the abrasive particle separation system adsorbs ferromagnetic abrasive particles through a high-gradient magnetic field, and the image acquisition system shoots abrasive particle images through a transflective double-color light source and an automatic focusing objective lens. The method comprises the following three steps: firstly, separating abrasive particles through ultrasonic massage vibration and spray backwashing, then depositing the abrasive particles through a magnetic field, and finally, identifying the type of the abrasive particles through image processing and judging the wear degree. The method has the advantages of simplicity and convenience in operation, high detection precision and capability of qualitatively and quantitatively analyzing the abrasive particles, and is suitable for monitoring the wear state of a fuel system.

A power inductor includes a coil and an induced magnetic element. The coil includes two outer loop circuit layers and a plurality of insulation spacing layer. The outer loop circuit layers are stacked up and electrically connected to each other. The outer loop circuit layers have an outer connection end apiece. At least one insulation spacing layer is located between the outer loop circuit layers. The induced magnetic element encapsulates the coil and exposes the outer connection end of each of the outer loop circuit layers. The induced magnetic element includes a plurality of ferromagnetic particles. The ferromagnetic particles include an iron-based alloy particle and an insulation film covering the iron-based alloy particle apiece.

The invention discloses a liquid metal grouting detection method and system based on aviation transient electromagnetism, and the method comprises the steps: forming composite slurry based on a liquid metal substrate and ferromagnetic particles; generating modified slurry based on the composite slurry and a cement-based grouting material; the modified slurry liquid is pressed and injected into a target rock mass fracture; the unmanned aerial vehicle is used for emitting electromagnetic pulses to the target rock mass and collecting secondary field response signals, and detection is completed. An aviation transient electromagnetic technology is adopted to replace a traditional ground geophysical prospecting method, a large-range area is rapidly scanned through the unmanned aerial vehicle carrying equipment, complex terrains (such as mountainous regions and rivers) can be climbed over, shielding of ground buildings can be avoided, the single-day detection efficiency is improved by more than three times, and the detection precision is improved. The method is especially suitable for scenes such as urban dense areas or plateau frozen soil where manual stationing is difficult.

The invention belongs to the technical field of steam turbine generator unit monitoring, and particularly relates to a steam turbine generator unit oil leakage fault prediction method which comprises the following steps: measuring the temperature of an oil return port of a speed regulation steam valve in real time, and if the temperature is abnormally increased, determining that oil leakage occurs in the speed regulation steam valve; the motor current and power of the high-pressure adjusting oil station are measured in real time, and if the motor power is increased, the oil system leaks oil; oil pressure in the oil pipe is monitored in real time, if the oil pressure is reduced, oil leakage occurs, and the specific oil leakage position is comprehensively judged according to the temperature and the motor power; and the granularity of the ferromagnetic particles is monitored at the position needing to be lubricated, and if the granularity becomes small, it is judged that lubricating oil leaks at the lubricating position. The method has the beneficial effects that the monitoring precision is high, detection points are comprehensive, oil leakage and lubricating oil leakage at all positions of the steam turbine generator unit can be effectively detected, the detection result can be quickly processed after being sent, the response is timely and quick, and efficient and safe operation of the steam turbine unit is ensured.

The embodiment of the utility model provides a residual liquid treatment mechanism of a photocuring printer. The residual liquid treatment mechanism comprises a waste liquid collection box; the scraping plate is arranged at the top of the waste liquid collecting box and can move up and down along the box wall; the filter screen is arranged in the waste liquid collecting box and is used for intercepting large-particle impurities in the resin; the inclined guide plate is positioned at the bottom of the waste liquid collecting box, is downwards inclined and is used for guiding the resin to flow into the low-position area of the waste liquid collecting box; the magnetic adsorption assembly is mounted at the position, close to the waste liquid discharging opening, of the inclined guide plate and used for removing ferromagnetic particles in the resin under the action of a magnetic field; wherein the interior of the waste liquid collecting box is provided with a gradually-shrunk structure; a convex edge is arranged on the surface of the inclined guide plate; a stirring rod is arranged on one side of the magnetic adsorption assembly, a driving motor is connected to the stirring rod, and the driving motor drives the stirring rod to rotate regularly. Through the scheme of the embodiment of the invention, the problem of how to optimize the residual liquid collecting container so as to more thoroughly recover the residual resin can be solved.

The invention discloses a magnetic abrasive material based on an ultraviolet curing technology at normal temperature and a preparation method thereof, and belongs to the technical field of precision and ultra-precision machining. The magnetic abrasive material is composed of hard abrasive material particles, ferromagnetic particles and an ultraviolet curing adhesive. The preparation method of the magnetic abrasive material comprises the following steps that the hard abrasive material particles and the ferromagnetic particles are evenly mixed according to a certain mass ratio; adding an ultraviolet curing adhesive in a specific viscosity range, and stirring until the adhesive uniformly coats the surfaces of the particles; compacting the mixture into a thin layer; carrying out multi-direction curing under ultraviolet irradiation to form a cured green body layer; and crushing and screening the cured green body layer to obtain the magnetic grinding material with the required particle size. The method is carried out at the normal temperature, high-temperature treatment is not needed, equipment is simple, cost is low, production efficiency is high, the hardness, toughness and magnetic response performance of the abrasive can be flexibly adjusted and controlled by adjusting the adhesive formula, the particle proportion and the curing process, and the method is suitable for small-batch customized magnetic abrasive production.

The invention provides an on-line detection method for copper particles in industrial lubricating oil liquid. The method comprises the following steps: expanding data of the content of non-ferromagnetic particles and the content of copper particles in the lubricating oil liquid, which are measured by experiments; according to the measured data of the non-ferromagnetic particles and the copper particles, an operation program of a BP neural network is written, the structure of the BP neural network is defined, and parameters are initialized; based on the obtained data of the content of the non-ferromagnetic particles and the content of the copper particles in the oil liquid, repeatedly training the data by utilizing a BP neural network program so as to obtain a statistical relationship between the content of the non-ferromagnetic particles and the content of the copper particles; according to the method, built-in parameters of a BP neural network program are optimized through a genetic algorithm, a statistical relationship with higher accuracy between the non-ferromagnetic particles and the copper particles is obtained and serves as a copper particle prediction model, and the content of the copper particles in the oil can be obtained by measuring the content of the non-ferromagnetic particles in the oil. And establishing a copper particle online detection method.

The utility model discloses a combined type side material blocking device for a roller press, which belongs to the technical field of roller grinding and crushing equipment and comprises a side baffle plate which is arranged on one side of the end part of a press roller; the wear-resistant plate is fixed on the side baffle plate and is positioned between the compression roller and the side baffle plate; the strong magnet is fixed on the side baffle plate, and the side baffle plate is positioned between the strong magnet and the wear-resisting plate; the wear-resisting plate is arranged between the side baffle and the compression roller, the strong magnet is arranged on the side face, opposite to the compression roller, of the side baffle, the strong magnet can generate a magnetic field at the wear-resisting plate, in the material crushing process, ferromagnetic particles can be adsorbed to the wear-resisting plate, and the ferromagnetic particles form a protective layer on the wear-resisting plate; the wear speed of the wear-resisting plate can be effectively reduced, the service life is prolonged, and the wear-resisting plate is detachably connected with the side baffle, so that replacement and maintenance are facilitated.

A power inductor includes a coil, a plurality of insulating spacer layers, and an inductive body. The coil comprises two outer loop circuit layers. The outer loop line layers are stacked and electrically connected with each other. And each outer loop circuit layer is provided with an external connecting end. At least one insulating spacer layer is located between the outer loop circuit layers. The magnetic induction body wraps the coil and exposes the external connection end of each outer loop circuit layer. The magnetizer includes a plurality of ferromagnetic particles. Each ferromagnetic particle includes an iron-based alloy particle and an insulating film covering the iron-based alloy particle. By using the insulating spacer layer, the insulating resistance can be effectively improved, so that the occurrence of short circuit can be avoided.

The invention provides physical vapor deposition equipment which is applied to the technical field of semiconductors. Specifically, a part of components in the physical vapor deposition equipment are transformed into one or more electromagnets, then each electromagnet is electrically connected with a control power supply, and the magnitude and existence of electrifying current of the electromagnets can be respectively controlled through the control power supplies which are correspondingly and electrically connected with different electromagnets; according to the invention, a plurality of electromagnets are arranged in the reaction chamber, so that the plurality of electromagnets generate magnetic fields with controllable distribution in different regions, and the concentration of ferromagnetic particles such as nickel and the like in the reaction chamber is redistributed under the control of the magnetic fields, so that homogeneous metal films with different thicknesses are formed on different region surfaces (different regions) of a single substrate to be coated in the same deposition process; and the uniformity and filling performance of the homogeneous metal film can be simply and efficiently adjusted by controlling the magnetic field, namely, the purposes of improving the deposition speed, the overall deposition uniformity, the deposition efficiency and the fineness of the metal film are achieved.

The invention provides a magnetic composite fluid polishing solution and a preparation method thereof, and belongs to the technical field of recovery and treatment of industrial waste residues. The magnetic composite fluid polishing solution provided by the invention comprises the following components in percentage by mass: 20-50% of carbonyl iron powder, 5-15% of modified nickel slag, 7-20% of abrasive particles, 1-5% of cellulose and 30-50% of magnetic fluid, the preparation method of the modified nickel slag comprises the following steps: mixing nickel slag with alkaline oxide to obtain pretreated nickel slag; and the pretreated nickel slag is subjected to melting oxidation, and the modified nickel slag is obtained. According to the method, the nickel slag is mixed with the alkaline oxide, the alkalinity of the nickel slag is adjusted, and subsequent melting oxidation of the nickel slag is facilitated; and then melting oxidation is carried out, ferromagnetic particles in the nickel slag are reduced, the modified nickel slag is obtained, carbonyl iron powder is partially replaced with the modified nickel slag, and the additional value of the nickel slag can be increased on the basis that the polishing effect of the magnetic composite fluid polishing solution is guaranteed.

The present invention relates to an additive in the form of a composite comprising ferrimagnetic particles of at least one iron-containing oxide, at least one first expanding agent having a structure whose volume can be increased by at least 50% by heating, and optionally at least one second expanding agent different from the at least one first expanding agent, which is at least one gas-releasing expanding agent, wherein the weight percentage of the ferrimagnetic particles, the weight percentage of the at least one first expanding agent and optionally the weight percentage of the at least one second expanding agent, each based on the total weight of the additive, supplement each other to at least 95% by weight, based on the total weight of the additive.Furthermore, the present invention also relates to a method for producing the additive, as well as to an adhesive composition comprising at least one additive according to the invention and its production. The present invention also further relates to the use of the additive in an adhesive composition.