2580 results about "Magnetic powder" patented technology

The invention discloses a nondestructive testing device for a steel profile and a testing method of the nondestructive testing device. According to the method disclosed by the invention, the ultrasonic technology is combined with optical imaging, so that synchronous detection of surface and internal defects can be completed at one time. Ultrasonic waves penetrate through the interior of the steel profile, and hidden defects such as cracks and air holes are accurately recognized; the optical camera module captures visible problems such as surface scratches and corrosion in real time. The integrated detection mode avoids the tedious process of step-by-step operation required by a traditional method, for example, magnetic powder detection of surface defects and ultrasonic scanning of an internal structure are not needed, the detection period is greatly shortened, and the method is especially suitable for steel structure buildings, bridge engineering and other scenes with high requirements for detection efficiency and has good application prospects. The full-process automatic design effectively reduces the influence of human intervention, and ensures the scanning continuity of the detection area; the intelligent algorithm automatically analyzes the ultrasonic echo signal and the optical image data, and judges the defect level according to the preset standard, thereby avoiding subjective misjudgment of manual visual inspection.

The invention discloses a preparation method of low-loss high-saturation iron-nickel soft magnetic powder. Comprising the following steps of S1, alloy smelting and S2, atomization. S3, carrying out ball milling treatment; s4, annealing treatment; s5, carrying out surface coating; the low-loss high-saturation iron-nickel soft magnetic powder is prepared from the following raw materials in percentage by weight: 77.6%-78.2% of electrolytic nickel, 21.4%-22.3% of electrolytic iron and 0.1%-1% of an additive, the performance of the iron-nickel soft magnetic powder and a magnetic powder core prepared by the process is improved in multiple aspects, and the iron-nickel soft magnetic powder has great application advantages.

The invention discloses a self-adaptive adjustment method and system for twisting tension of a copper stranded wire. According to a state analysis result, a dynamic coupling adjustment mechanism is started, rapid response adjustment of tension is achieved by adjusting the matching relation between the rotating speed of a stranding cage and the linear speed of a traction wheel and linkage with the exciting current of a magnetic powder brake, tension data are rapidly collected through a sensor, and after filtering and abnormal value processing, the tension is obtained. The fluctuation frequency and amplitude are analyzed immediately, and adjustment is started once the fluctuation frequency and amplitude exceed a set range. During adjustment, the ratio of the rotating speed of the stranding cage to the speed of the traction wheel is adjusted, the current of the magnetic powder brake is linked, mechanical adjustment and electromagnetic braking are matched, and the response speed is much faster than that of traditional single-parameter adjustment. Therefore, the stress of the copper stranded wire in the stranding process is uniform, the wire diameter is not thinned or burrs are not formed on the surface due to sudden change of tension, the stranded wire pitch is uniform, the process requirement is met, and the influence on the stranded wire quality due to sudden change of the tension is avoided as much as possible.

The invention relates to the technical field of inductors, in particular to an inorganic insulation integrally-formed power inductor and a preparation method thereof. The method comprises the following steps: S1, selecting a coil; s2, pre-stretching the coil; s3, pre-coating of inorganic powder is carried out; s4, pressing the magnetic powder; s5, sintering the ceramic layer at high temperature; and S6, integrally forming the inductor. By reasonably selecting the material and shape of the coil and the type of the magnetic powder and combining high-temperature sintering at the temperature of 250 DEG C or above, the magnetic conductivity and the bias resistance are improved, the diversified requirements of high frequency, high temperature, high power density and the like are met, and the performance of insulation, heat conduction and the like can be optimized; according to the integrated forming process, coil pre-packaging and magnetic core forming are completed in one step, production procedures are reduced, process integration and production efficiency are improved, production cost is reduced, the utilization rate of a magnetic core window reaches 100%, and the product size is reduced.

The invention relates to the technical field of magnetic materials, in particular to a ferrite neodymium iron boron composite magnetic material and a preparation method thereof. The ferrite neodymium iron boron composite magnetic material comprises the following raw materials in parts by weight: 20-30 parts of ferrite magnetic powder, 40-50 parts of neodymium iron boron magnetic powder, 5-10 parts of silicon dioxide, 2-5 parts of carbon nanotubes, 0.5-1 part of polyethylene and 0.5-2 parts of polyimide. The high-temperature-resistant and corrosion-resistant permanent magnet has high magnet performance and also has high-temperature-resistant performance and corrosion-resistant performance.

The invention discloses a motor coil winding device and method, and belongs to the technical field of motor manufacturing, the motor coil winding device comprises a winding machine body, the upper surface of the winding machine body is fixedly connected with a pair of supporting plates, and the outer surfaces of the supporting plates are provided with self-adaptive floating wire protection assemblies; a wire dynamic regulation and control assembly is installed on the upper surface of the winding machine body, a fixing piece is installed on the upper surface of the winding machine body, and a winding displacement quality sensing assembly is installed on the portion, close to the fixing piece, of the upper surface of the winding machine body. The magnetorheological fluid in the magnetorheological fluid damper rapidly changes the rheological property under the action of a real-time control magnetic field, vibration transmission is effectively restrained, the phenomenon that a wire is broken due to too large tension is avoided, when it is monitored that the tension is too small, the magnetic powder brake increases the resisting moment and slows down the rotating speed of the pay-off reel to improve the tension, and if the tension is too large, the magnetic powder brake stops working. The magnetic powder brake reduces the resistance moment and accelerates the pay-off, and ensures that the wire is always at the optimal traction angle.

The invention relates to the technical field of mutual inductor production, in particular to a coil winding device for mutual inductor production. The coil winding device comprises a rack and a winding wheel, the winding wheel is rotationally supported on the rack through a plurality of supporting wheels, the winding wheel is provided with a C-shaped notch used for containing an iron core, and the winding wheel comprises a middle ring and side rings located on the two sides of the middle ring; the side rings and the middle ring are coaxial and are arranged in a mutually rotating mode, the circumferential wall of the middle ring is used for winding a copper wire, and one side ring is provided with a wire penetrating ring used for penetrating the end of the copper wire. The tensioning assembly is used for clamping the copper wire between the iron core and the threading ring; the magnetic powder brake is connected to the supporting wheel and provides resistance for the middle ring through the supporting wheel so as to tension the copper wire; and the driving assembly is used for driving the side ring to rotate and winding the copper wire on the iron core. Resistance is provided by the magnetic powder brake through the middle ring of the reel, so that tensioning of a copper wire can be controlled, and the winding quality of the copper wire on an iron core is improved.

The invention discloses a high-sensitivity tactile sensing system based on a magnetic cilia array, a sensor comprises the magnetic cilia array and a sensor array, and the magnetic cilia array is attached to the upper surface of the sensor array; the magnetic cilia array comprises a substrate and cilia structures which are orderly arranged and fixed on the substrate; the cilia structure is made of ecological silicone rubber mixed with magnetic powder, and a plurality of groups of sensors are adopted to form a sensor array to construct a sensing system. By optimizing the magnetization process, uniform distribution of the magnetic particles in each cilium is ensured, and the output stability and sensitivity of the sensor are improved; meanwhile, the multi-sensor array layout is adopted, and high-precision sensing of multi-dimensional tactile information such as pressure, direction and vibration is achieved.

The invention provides an environment-friendly fabric printing and dyeing wastewater treatment system and method, and belongs to the technical field of wastewater treatment. An environment-friendly fabric printing and dyeing wastewater treatment system at least comprises a water storage tank, two flocculation tanks, two sedimentation tanks, a transition tank, an oxidation tank, a secondary sedimentation tank, a BAF tank, a disinfection tank and a discharge tank which are connected in sequence, the two flocculation tanks are connected to the water storage tank at the same time, the two sedimentation tanks are connected to the two flocculation tanks in a one-to-one correspondence mode, and the two sedimentation tanks are connected to the BAF tank in a one-to-one correspondence mode. The two sedimentation tanks are connected to the transition tank at the same time; adding a flocculating agent and magnetic powder into the flocculation basin at the same time; each sedimentation tank is internally provided with a treatment mechanism for accelerating sedimentation of magnetic flocs and rapidly removing suspensions, each sedimentation tank is internally provided with a water outlet assembly capable of being adjusted in height, and the water storage area of the transition tank is lower than the water outlet assembly. The sewage treatment device has the advantage of improving the sewage treatment efficiency.

The invention discloses a heat supply pipeline welding seam detection device, and relates to the technical field of heat supply pipeline processing, the heat supply pipeline welding seam detection device comprises a transmission mechanism 1 and a detection bin, the transmission mechanism 1 is provided with an inverted U-shaped support, the bottom wall of the horizontal section of the inverted U-shaped support is slidably connected with magnetization members in a front-back symmetrical manner, and the inverted U-shaped support is provided with a clamping member and a pretreatment mechanism; a detection bin is arranged on the left side of the first conveying mechanism, and a transferring mechanism, a marking mechanism and a second conveying mechanism are arranged on the detection bin. Through cooperation of the driving assembly and the brushing assembly, the outer wall of the to-be-detected pipe fitting is brushed, the situation that magnetic powder, oxide skin, burrs and the like adhere to the surface of the pipe fitting, the magnetic powder gathering phenomenon caused by non-defect factors is caused, and misjudgment occurs in the detection process is avoided, through cooperation of the driving assembly and the flushing assembly, the pipe fitting is flushed, and the detection efficiency is improved. The scraped impurities are prevented from being attached to the outer wall of the to-be-detected pipe fitting, and meanwhile, the pre-wetting treatment can be carried out, so that the fluorescent magnetic suspension is helped to cover the surface of the pipe fitting more uniformly.

The invention discloses a self-adaptive adjustment magnetic separation-membrane filtration coupling sewage treatment system and a self-adaptive adjustment magnetic separation-membrane filtration coupling sewage treatment method. The system comprises a pretreatment unit, a magnetic separation core unit, a self-adaptive intermediate buffer unit, a membrane filtration unit and a sludge treatment unit which are communicated in sequence. The core of the system is that a plurality of on-line sensors are linked through a central control system, water quality parameters are monitored in real time, the adding amount of magnetic powder and a coagulant, the rotating speed of a stirrer, the membrane flux, the backwashing period and a cleaning program are adjusted in a self-adaptive mode, and intelligent cooperation and accurate regulation and control of magnetic separation and membrane filtration processes are achieved. According to the invention, the problems of easy membrane pollution, high magnetic powder consumption, high operation cost and dependence on manual operation in the traditional process are effectively solved, the service life of the membrane is obviously prolonged, the operation and maintenance cost is reduced, and the effluent quality is stable and meets the high-standard discharge or reuse requirement.

The invention discloses a method and device for testing the fatigue crack growth rate of a metal material based on temperature gradient change, and relates to the technical field of metal material detection. Mounting a constant low-temperature component and a constant high-temperature component close to two ends of the sample respectively; pasting a plurality of thermocouples on the middle surface of the sample; a magnetic powder dynamic moving assembly is installed on the surface of the sample, and a constant-temperature state is given to magnetic powder; loading a bidirectional tension-compression fatigue testing machine along the through hole of the sample; a thermal imager is arranged far away from the parallel sample, and a thermal imaging image is shot; according to the data, the fatigue crack growth rate of the sample at the corresponding temperature is obtained; according to the method, the fatigue crack growth rate of the metal material can be rapidly tested, meanwhile, the temperature gradient is formed in the sample, the influence of the temperature on the crack growth rate can be obtained in different temperature areas, the device required by the whole test is simple in structure, low in cost and convenient to load and disassemble, and the whole efficiency of the test is effectively improved.

The present invention discloses a wall-climbing robot for weld detection, which includes a top plate, a flaw detection mechanism, a magnetic wheel mechanism, a sensor assembly, a liquid supply mechanism, a gravity feedback mechanism, and a controller. An industrial camera in the sensor assembly detects the weld. The controller drives the rotation of four groups of magnetic wheel mechanisms for weld tracking according to the weld detection result. The gravity feedback mechanism drives the water pump in the liquid supply mechanism to continuously spray magnetic suspension liquid on the weld to be detected according to the gravity detection result. The first servo motor in the flaw detection mechanism drives the magnetic particle flaw detector to move downwards to continuously detect the weld to be detected. The device has a simple structure. Through four independent groups of magnetic wheel mechanisms, it can adapt to different container wall surfaces. At the same time, through gravity detection, continuous liquid supply of the liquid supply mechanism is realized, improving the efficiency, accuracy and reliability of weld detection.

The utility model discloses an integrated magnetic flocculation device system and relates to the technical field of water treatment devices. The device comprises a device shell, a central cylinder, a conical mud bucket, a water inlet pipe, a flocculant dosing pipe, a pipeline mixer, a gas inlet pipe for gas stripping, a coagulant aid dosing pipe, a water outlet pipe and a mud discharge pipe, according to the utility model, when water enters, a flocculant is added and mixed on a water inlet pipe by using a pipeline mixer, after water enters the magnetic coagulation area, compressed air is used as a power source for circulation and mixing, a coagulant aid is added above an air release port, supplementary magnetic powder is added to an upper opening of a central cylinder, and water subjected to magnetic coagulation reaction enters the precipitation separation area; when the magnetic coagulation reaction device is used, supernatant is collected by the water collecting tank and then discharged, precipitated sludge containing magnetic powder can slide into the conical sludge bucket to be treated again, redundant sludge is discharged through the sludge discharging pipe, the whole magnetic coagulation reaction and sludge-water separation treatment process is completed in one device, and an independent backflow system is not needed.

The invention belongs to the field of soft magnetic functional materials, and particularly relates to a low-loss high-superposition Fe-Si-Al magnetic powder core and a preparation method thereof, and the preparation method comprises the following steps: preparing a coating agent, passivating coated powder, bonding and lubricating, and pressing and annealing. According to the method, based on the hydrolysis characteristic of metasilicic acid and the hydrolysis promotion effect of the alkaline catalyst, nano-porous silicon dioxide is prepared as a coating agent, meanwhile, the etching effect of alkaline matter on silicon dioxide can effectively increase the specific surface area of the nano-porous silicon dioxide, and the bonding strength of the nano-porous silicon dioxide and iron-silicon-aluminum powder is improved; the vacuum calcination treatment not only removes residual reagents, but also promotes sufficient thermal decomposition of metasilicic acid into silicon dioxide for in-situ coating, and stabilizes the lattice structure of the metasilicic acid. The coating layer of the low-loss high-superposition Fe-Si-Al magnetic powder core is firm in combination, thin and uniform in thickness and stable and compact in structure, the hysteresis loss of the Fe-Si-Al magnetic powder core can be effectively reduced, the direct-current bias performance is improved, and rising of eddy-current loss is avoided.

The invention relates to the field of PU, and particularly discloses a far infrared magnet therapy PU seat skin and a preparation method thereof.The far infrared magnet therapy PU seat skin sequentially comprises a base cloth layer, a solvent-free bonding layer, a high-solid foaming layer, a polyurethane surface layer and a surface layer from bottom to top; the high-solid foaming layer is prepared from the following components in parts by weight: 70 to 90 parts of high-solid resin, 5 to 8 parts of a cross-linking agent, 0.5 to 1.5 parts of a foaming agent, 0.5 to 1.0 part of a flatting agent, 10 to 15 parts of a flame retardant, 0.05 to 0.2 part of color paste, 10 to 20 parts of far infrared ceramic micro powder and 2 to 8 parts of germanite magnetic powder. The seat skin has a good far infrared ray transmission effect and high strength, and has a good health care effect.

The invention belongs to the technical field of neodymium iron boron rare earth permanent magnets, and relates to a cerium-containing neodymium iron boron magnet with high coercivity and high stability and a preparation method thereof. According to the preparation method, the cerium-containing copper auxiliary alloy and the neodymium iron boron magnetic powder are ingeniously combined, the whole preparation process is optimized, and remarkable technical progress and economic benefits are achieved. Firstly, in the aspect of magnetic performance, Ce in a specific proportion is added into the cerium-containing copper auxiliary alloy, the cerium-containing copper auxiliary alloy is used, the coercive force of a magnet is effectively improved, high residual magnetism is kept to a certain degree, and introduction of Cu is beneficial to refining of grains and improvement of a grain boundary phase structure; therefore, the reverse magnetization resistance in the magnet is enhanced, and the magnet can maintain stable performance in a wider temperature range.

The invention relates to the technical field of injection molding magnetic powder materials, and discloses an injection molding magnet material, a preparation method and an injection molding magnet, and the injection molding magnet material is prepared from the following raw materials in parts by weight: 80-92 wt.% of magnetic powder; 3-9 wt.% of a binder A; 3-9 wt.% of a binder B; 0.3 to 2 wt.% of a coupling agent; 0.2 to 1.5 wt.% of an auxiliary agent; the binder A and the binder B are PA10T / X, the relative viscosity of the binder A and the relative viscosity of the binder B range from 1 to 2, and the difference value between the relative viscosity of the binder A and the relative viscosity of the binder B is not less than 0.3. The binding agent A and the binding agent B with different relative viscosities are adopted for improving the mechanical property and the fluidity of the magnetic material correspondingly, it can be guaranteed that the magnetic material has good size stability in a high-humidity environment and has high strength in a low-temperature environment, the fluidity of the magnetic material is greatly improved, and the magnetic material has the good mechanical property. Meanwhile, the material cost of the injection molding magnet material is reduced.

The invention relates to the field of sewage treatment, and discloses an intelligent magnetic coagulation sewage treatment system and method.The system comprises a water purification unit, a multi-source sensing unit, a decision unit and a dynamic execution unit; wherein the water purification unit is composed of a coagulation tank, a flocculation tank, a mixed reaction tank, a sedimentation tank and a magnetic separation device which are sequentially communicated, and each tank is provided with a stirrer; the multi-source sensing unit is used for collecting inflow water quality data, floc morphological characteristics, mud layer thickness and sedimentation rate in real time; the decision-making unit receives the data and then outputs PAC, PAM and magnetic powder adding instructions; the dynamic execution unit comprises an intelligent dosing group, a magnetic separation device and an intelligent sludge discharge valve, the magnetic field intensity can be adjusted according to the treatment load, sludge discharge is controlled based on the sludge layer compactness, and the system has three operation modes of domestication, conventional low carbon and emergency response, so that efficient and low-carbon sewage treatment can be realized, and the treatment efficiency and stability are improved.

A raw material solution containing trivalent iron ions, or trivalent iron ions and ions of a metal element that partially substitutes Fe sites, and an alkaline aqueous solution for neutralizing the raw material solution are added to a reaction system to adjust the pH of the reaction system from 1.0 to 3.0 or lower. Hydroxycarboxylic acid is added to the obtained reaction solution and the pH of the reaction system is then neutralized from 7.0 to 10.0 or lower. The obtained precipitate of a substituent metal element-containing iron oxyhydroxide is coated with silicon oxide, followed by heating so as to form particles of ε-iron oxide in which Fe sites are partially substituted by other metal elements, and then, a slurry containing the particles is classified. The iron-based oxide magnetic powder has a particle shape close to a perfect sphere and is suitable for use in a magnetic recording medium.

The invention discloses a sintered neodymium-iron-boron magnet and a preparation method and application thereof. The magnet comprises main phase crystal particles with RE2Fe14B structures and a grain boundary phase. The grain boundary phase comprises a two-particle grain boundary phase between two main phase crystal particles and a grain boundary triple-phase point composed of more than three main phase crystal particle gaps; the ratio of the number of the main phase crystal particles to the number of grain boundary triphase points is smaller than or equal to 3. According to the sintered neodymium-iron-boron magnet, through proper component design, reasonable control over the (Cu + Ga) / X ratio and control over the thickness of an alloy sheet and the ratio relation between the average width of columnar crystals in the alloy sheet and the granularity of magnetic powder, concentrated distribution of grain boundary three-phase points can be effectively restrained, the grain boundary phase proportion can be increased, grain boundary phase distribution can be optimized, and the performance of the sintered neodymium-iron-boron magnet can be improved. Therefore, both high magnetic performance and high impact toughness are achieved. The sum of the magnetic energy product and the coercive force of the sintered neodymium-iron-boron magnet is larger than or equal to 75, the impact toughness of the sintered neodymium-iron-boron magnet is larger than or equal to 20 kJ / m < 2 >, and the sintered neodymium-iron-boron magnet can be applied to new energy automobile motors, energy-saving

The invention discloses a boiler pressure vessel inner surface crack detection device and method, and relates to the field of crack detection, and the boiler pressure vessel inner surface crack detection device comprises a driving unit, a supporting unit and a magnetic powder detection unit. According to the boiler pressure vessel inner surface crack detection device and method, the magnetic powder detection unit is fixedly supported through the supporting unit, and the cylindrical part is driven to spirally move through the driving unit, so that the inner wall of the cylindrical part is annularly and continuously detected; the magnetic powder smearing piece is automatically driven to smear magnetic powder to the inner wall of the cylindrical piece, meanwhile, the scraping roller automatically scrapes and recovers the magnetic powder in the detected area, the magnetic powder smearing process is more stable and uniform, equipment is more stable in the detection process, meanwhile, the magnetic powder recovery rate is higher after detection, the design is simple, the number of power sources is small, and the equipment cost and the control cost are reduced.

The application relates to the technical field of integrally-formed inductors, in particular to a moisture-resistant soft magnetic composite material and a preparation method thereof and an integrally-formed inductor. The moisture-resistant soft magnetic composite material comprises the following components by mass: 100 parts of soft magnetic powder, 2-5 parts of a resin bonding agent and silicon resin, wherein the mass ratio of the silicon resin to the resin bonding agent is (0.3-2.0):100. The moisture-resistant soft magnetic composite material can avoid the phenomenon of explosion of the integrally-formed inductor during a reflow soldering process after moisture absorption.

The invention provides an inductor structure and a preparation method thereof.The preparation method of the inductor structure comprises the steps that a leading-out wire of a coil is placed on a welding piece of an end pole piece, and the end pole piece comprises a pin piece and the welding piece which are connected with each other; the welding piece is bent, so that the outgoing line is wrapped by the welding piece; the outgoing line and the welding piece are welded together to form a first-order preformed inductor; the first-order preformed inductor is placed in a mold cavity, the mold cavity is filled with magnetic powder, and the pin piece extends out of the mold cavity; carrying out a die-casting process on the mold cavity to enable the magnetic powder to form a magnetic core entity so as to obtain a second-order preformed inductor; and the mold cavity is removed, and the pin pieces are bent and attached to the surface of the magnetic core entity, so that the inductor structure is obtained. The integrally-formed inductor solves the problems that the coil leading-out end and the end pole piece of an existing integrally-formed inductor are low in welding reliability and large in cold joint risk.

The invention discloses a full-automatic ultrasonic and magnetic powder synchronous nondestructive testing system and method for a bearing ring, and belongs to the technical field of bearing nondestructive testing. The testing system comprises a main testing system, a demagnetizer, a truss mechanical arm and an electric control cabinet; the main detection system comprises a detection module, a motion module, a hanging rod module, a jacket module, a magnet yoke, a lifting module, a magnetic liquid nozzle and a liquid collecting tank; the detection module comprises a vision assembly and an ultrasonic assembly which can be movably controlled; the bearing ring is hung on a rotating hanging rod shaft in the hanging rod module and limited. The system can carry out nondestructive testing on all the surfaces and the interior of the rotating bearing ring, the demagnetizer is used for carrying out pre-testing magnetism and post-testing magnetism, the truss mechanical arm is used for transferring the bearing ring, and full-automatic detection is achieved through a control method. According to the invention, the technical problem that all surface and internal defects of the large bearing ring are difficult to automatically and simultaneously detect in a nondestructive manner at one time in the prior art is solved, and the bearing ring with a large size range can be detected.

The present invention discloses an ultra-thin flexible magnetic adsorption eyelash magnetic sheet and a preparation method thereof, which relates to the technical field of magnetic adsorption eyelashes. Each group of eyelash magnetic sheets is composed of upper and lower magnetic sheets. Opposite adsorption magnetic poles are arranged on the two magnetic sheets respectively, and the magnetism of the opposite adsorption magnetic poles shows a gradient distribution of strong at the edge and weak in the middle on the magnetic sheet. The raw materials of the magnetic sheet include samarium iron nitride magnetic powder and polypropylene. Samarium iron nitride is non-toxic and resistant to sweat corrosion, and polypropylene meets the cosmetic grade standard, improving the biological safety and solving the problem of unreliable materials for traditional magnetic adsorption eyelashes. The magnetic sheet is designed as an opposite adsorption magnetization structure, and the upper and lower magnetic sheets can achieve firm adsorption, overcoming the defect of easy falling off of traditional magnetic adsorption eyelashes. The thickness is only 0.14 - 0.24 mm, and it does not break after being folded more than 500 times, conforming to the curvature of the eye, being comfortable to wear, and avoiding the defect of heaviness of traditional magnetic adsorption eyelashes.

The invention provides a high-density mould pressing bonding samarium-iron-nitrogen magnet with an extremely low cavity volume ratio and a preparation method of the high-density mould pressing bonding samarium-iron-nitrogen magnet, and belongs to the technical field of magnets, and the high-density mould pressing bonding samarium-iron-nitrogen magnet is prepared from a binder, a lubricant and the balance of samarium-iron-nitrogen magnetic powder. The preparation method comprises the following steps: performing surface treatment on the samarium-iron-nitrogen magnetic powder; dissolving a binder with an organic solvent, and adding the treated magnetic powder and a lubricant to obtain clinker; preheating a pressing mold, and preheating the clinker to 20-120 DEG C; the pressing force ranges from 6 T / cm < 2 > to 50 T / cm < 2 >, the pressing and pressure maintaining time ranges from 0.3 second to 150 seconds, meanwhile, a mold cavity of the mold is vacuumized, air among powder particles is exhausted, and finish machining is carried out after a compact structural body is formed. Through vacuum grease overflow compression molding, effective filling of cavities in the magnet is achieved, redundant resin overflows out of contact points among magnetic powder particles, the cavity rate of the magnet is remarkably reduced, the density of the samarium-iron-nitrogen magnet under the same pressure condition is remarkably improved, the crushing degree of the magnetic powder particles is reduced, and finally the magnetic performance of the magnet is remarkably improved.

The invention discloses a welding seam change detection device for a steel structure, and relates to the technical field of welding seam detection, the welding seam change detection device comprises a detection platform, a magnetic powder box is arranged in the middle of the upper end of the detection platform, four corners of the upper end of the detection platform are respectively provided with a group of stand columns, and the upper ends of the four groups of stand columns are provided with a group of top plates; fixing frame plates are arranged on the two sides of the lower end of the top plate correspondingly, the side walls of the two fixing frame plates are each provided with a screw rod, a connecting ring is arranged between the ends of the two screw rods, a first motor is arranged on the outer wall of one fixing frame plate, and the first motor is connected with the ends of the corresponding screw rod. The outer walls of the two sets of lead screws are each provided with a set of moving blocks. According to the welding seam change detection device for the steel structure, the position and the shape of the welding seam of the steel structure can be displayed through adsorption of the electromagnet and the magnetic suspension, and people can detect the welding seam of the steel structure more conveniently.

The invention discloses a high-temperature-resistant high-performance neodymium-iron-boron permanent magnet material and a preparation method thereof, and belongs to the technical field of neodymium-iron-boron permanent magnet materials. The material is prepared from neodymium iron boron magnetic powder, auxiliary metal, hyperbranched polyimide polymer modified nano zirconium oxide and a silane coupling agent through mixing, smelting, crushing, sintering, tempering, coating and curing. The hyperbranched polyimide polymer modified nano-zirconia is introduced into the components, so that the permanent magnet material has excellent thermal stability, the permanent magnet material can still keep stable magnetic performance and mechanical performance at high temperature, the attenuation resistance is good, the thermal demagnetization is low, and the interface bonding strength is improved after the nano-zirconia is modified by hyperbranched polyimide. The interfacial compatibility between the nano zirconium oxide and the polyimide is enhanced through click chemical reaction, and the interfacial bonding strength of the nano zirconium oxide on a neodymium iron boron matrix is improved. The three-dimensional branched structure of the hyperbranched polyimide can form physical crosslinking points in the material, so that the mechanical strength of the material is enhanced.

The invention provides a high-performance neodymium-iron-boron magnet formed by MIM (metal injection molding), which comprises the following components in percentage by weight: 28 to 38 weight percent of Re, 4 to 5 weight percent of FeB, 0.05 to 0.2 weight percent of Cu, 0 to 0.15 weight percent of Al, 0.15 to 0.3 weight percent of Ga, 0.2 to 1.5 weight percent of Co, 0.15 to 0.2 weight percent of Zr and the balance of iron and other inevitable impurities, the MIM injection molding process is carried out under the protection of nitrogen, the position of an extrusion material rod opening and the interior of a mold cavity are both under the protection of inert gas, and the extrusion material rod opening and the mold cavity are sealed. Meanwhile, a mold core is in a pulsed magnetic field environment in the injection molding process, it is guaranteed that the magnet has a proper neodymium-rich phase by regulating the rare earth content to be 28-38%, and therefore the coercive force of the magnet is improved, the compactness of the magnet is improved, the production cost is reduced, and through the optimized jet milling technology, the particle size and particle size distribution of neodymium-iron-boron powder are controlled, so that the yield of neodymium-iron-boron powder is improved. And meanwhile, the proportions of the magnetic powder with different particle sizes are adjusted through the sorting wheel, so that gap coating of the pre-coating solute is facilitated, and the injection molding density of the MIM neodymium iron boron is improved.