Resistivity optimization method and system for sintered NdFeB magnets based on alumina doping

Abstract

The present invention relates to the field of magnetic materials, and a method and system for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping, comprising: performing the following operations for each of a plurality of doping ratios: calculating the mass of alumina using the mass of NdFeB and the doping ratio, obtaining an alumina sample using the mass of alumina and the alumina powder, obtaining a NdFeB magnet using primary mixed magnetic powder, calculating the magnetic temperature response coefficient according to the high-temperature magnetic loss rate, the magnetic resistance induction rate and the magnet resistivity, calculating the magnetic energy balance efficiency according to the magnetic temperature response coefficient and the magnet energy efficiency product, summarizing the magnetic energy balance efficiency, obtaining a plurality of magnetic energy balance efficiencies, taking the doping ratio corresponding to the successful magnetic energy efficiency as the successful ratio, obtaining an optimized NdFeB magnet based on the NdFeB magnetic powder, the alumina powder and the successful ratio, and completing the optimization of the resistivity of the sintered NdFeB magnet. The present invention can optimize the resistivity of the NdFeB magnet and improve the comprehensive quality of the NdFeB magnet.

Description

Technical Field

[0001] The present invention relates to the field of magnetic materials, and in particular to a method, system, electronic equipment and computer-readable storage medium for optimizing the resistivity of a sintered NdFeB magnet based on aluminum oxide doping. Background Art

[0002] NdFeB magnets are widely used in motors, generators, sensors and other fields due to their excellent magnetic properties. However, the resistivity of NdFeB magnets is relatively low, and the eddy currents generated during operation are large, resulting in heat loss under the thermal effect of the eddy currents, which in turn affects the performance and life of NdFeB magnets.

[0003] At present, the method for improving the resistivity of sintered NdFeB magnets is usually to dope the NdFeB magnets with oxides so that the doped materials form a stable oxide layer at the grain boundaries of the NdFeB, thereby inhibiting the flow of electrons at the grain boundaries and increasing the resistance.

[0004] Although the existing doping method can improve the resistivity of sintered NdFeB magnets, the influence of different doping ratios on the magnetic properties of NdFeB magnets is not considered when doping oxides. When the doping ratio is too high, the magnetic properties of NdFeB magnets will be seriously reduced. Therefore, how to select a suitable doping ratio, balance the weights of resistivity and magnetic properties, and improve the comprehensive quality of NdFeB magnets has become an urgent problem to be solved. Summary of the invention

[0005] The present invention provides a method for optimizing the resistivity of a sintered NdFeB magnet based on aluminum oxide doping and a computer-readable storage medium, the main purpose of which is to optimize the resistivity of the NdFeB magnet and improve the comprehensive quality of the NdFeB magnet.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping, comprising: obtaining NdFeB magnetic powder and alumina powder, performing a uniform sampling operation on a preset doping ratio range to obtain multiple doping ratios, and performing the following operations on each of the multiple doping ratios: obtaining a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculating the alumina mass using the NdFeB mass and the doping ratio, and obtaining an alumina sample using the alumina mass and the alumina powder; performing a mixing operation on the alumina sample and the NdFeB sample using a pre-constructed mixer to obtain a primary mixed magnetic powder, and obtaining a NdFeB magnet using the primary mixed magnetic powder; obtaining a magnet sample using the NdFeB magnet, performing a detection operation on the magnet sample using a pre-constructed permanent magnet measuring instrument to obtain a test remanence and a sample coercive force, comparing the test remanence with a preset remanence threshold and comparing the sample coercive force with a preset coercive force threshold; if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is less than or equal to the remanence threshold, If the coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet; the target magnets are summarized to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained by using the target magnet, a magnet energy efficiency product is obtained by using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained by using the resistance test sample, and a high-temperature magnetic loss rate is obtained by using the temperature test sample; a magneto-temperature response coefficient is calculated according to the high-temperature magnetic loss rate, the magnetoresistance induction rate and the magnet resistivity, and a magnetic energy balance efficiency is calculated according to the magneto-temperature response coefficient and the magnet energy efficiency product; the magnetic energy balance efficiencies are summarized to obtain multiple magnetic energy balance efficiencies, the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio, and an optimized NdFeB magnet is obtained based on the NdFeB magnetic powder, the alumina powder and the successful ratio, so as to complete the resistivity optimization of the sintered NdFeB magnet.

[0007] Optionally, the method of obtaining NdFeB magnets using primary mixed magnetic powder includes: performing an airflow crushing operation on the primary mixed magnetic powder to obtain intermediate mixed magnetic powder, and extracting an intermediate magnetic powder sample from the intermediate mixed magnetic powder; performing a detection operation on the intermediate magnetic powder sample using a pre-built laser particle size analyzer to obtain a test magnetic powder particle size; comparing the test magnetic powder particle size with a preset magnetic powder particle size threshold, if the test magnetic powder particle size is greater than the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the primary mixed magnetic powder, and returning to the step of performing an airflow crushing operation on the primary mixed magnetic powder until the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold; if the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the target mixed magnetic powder; performing an orientation pressing operation on the target mixed magnetic powder to obtain a preliminary pressed magnetic block, performing a cold isostatic pressing operation on the preliminary pressed magnetic block to obtain a target pressed magnetic block; performing a vacuum sintering operation on the target pressed magnetic block to obtain a sintered magnetic block, and performing a graded tempering operation on the sintered magnetic block to obtain a NdFeB magnet.

[0008] Optionally, the step of performing a graded tempering operation on the sintered magnet block to obtain a neodymium iron boron magnet includes: using a pre-built infrared thermometer to perform a temperature measurement operation on the sintered magnet block to obtain an initial magnet block temperature, taking the time of obtaining the initial magnet block temperature as the starting point and recording the time in real time to obtain a first cooling time; performing a natural cooling operation on the sintered magnet block, and using an infrared thermometer to monitor the sintered magnet block in the natural cooling operation in real time to obtain a real-time temperature; obtaining a current room temperature, and when the real-time temperature reaches the current room temperature, using the sintered magnet block as the first cooling magnet block, and using the first cooling time to calculate a first insulation time, wherein the first insulation time is twice the first cooling time; using the current room temperature and the initial magnet block temperature to calculate the first stage temperature, and the calculation formula is as follows:

[0009] ,in, is the current room temperature, is the initial magnet temperature, is the first stage temperature; the temperature at which the pre-constructed vacuum tempering furnace is heated and kept warm is set as the first stage temperature to obtain the first tempering furnace, and the first cooling magnetic block is heated and kept warm by the first tempering furnace to obtain the first insulation magnetic block, wherein the time for keeping the first cooling magnetic block warm is the first insulation time; the time for obtaining the first insulation magnetic block is taken as the starting point and the time is recorded in real time to obtain the second cooling time, and the second cooling magnetic block and the second insulation time are obtained based on the first insulation magnetic block and the second cooling time, and the second stage temperature is calculated based on the current room temperature and the first stage temperature; the NdFeB magnet is obtained based on the second cooling magnetic block, the second stage temperature and the second insulation time.

[0010] Optionally, the obtaining of the magnet energy efficiency product by using the magnetic energy test sample includes: performing a weighing operation on the magnetic energy test sample to obtain a test mass; performing a detection operation on the magnetic energy test sample by using a permanent magnet measuring instrument to obtain a test magnetic energy product and a test coercive force; and calculating the magnet energy efficiency product by using the test remanence, sample coercive force, test coercive force, test mass and test magnetic energy product corresponding to the magnetic energy test sample, and the calculation formula is as follows:

[0011] ,in, is the magnet energy efficiency product, To test the residual magnetism, is the sample coercivity, To test the coercivity, To test the quality, To test the magnetic energy product, is the natural logarithm.

[0012] Optionally, the method of obtaining the resistivity and magnetoresistance induction rate of the magnet using the resistance test sample includes: starting a pre-constructed constant temperature test box, setting the temperature of the constant temperature test box after starting to be the current room temperature, and obtaining a first constant temperature box; placing the resistance test sample in the first constant temperature box, taking the time when the resistance test sample is placed in the first constant temperature box as the starting point and recording the time in real time to obtain the constant temperature time, and when the constant temperature time reaches a preset constant temperature time threshold, obtaining a first temperature measurement sample; performing a four-probe method test on the first temperature measurement sample in the first constant temperature box to obtain the resistivity of the magnet; updating the current room temperature corresponding to the first constant temperature box to a preset second experimental temperature to obtain a second constant temperature box, wherein the second experimental temperature is greater than the current room temperature; obtaining a second temperature measurement sample and a second resistivity based on the first temperature measurement sample and the second constant temperature box; calculating the magnet temperature variation coefficient using the current room temperature, the second experimental temperature, the magnet resistivity and the second resistivity, and the calculation formula is as follows:

[0013] ,in, is the temperature variation coefficient of the magnet, and are the magnet resistivity and the second resistivity, is the second experimental temperature; and the magnetoresistance induction rate is obtained using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample.

[0014] Optionally, the method of obtaining the magnetic resistance induction rate by using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample includes: placing the second temperature measurement sample in a pre-constructed alternating magnetic field generator to obtain a magnetic field test sample, wherein the alternating magnetic field generator includes: an AC power supply and a hollow solenoid, wherein the hollow solenoid includes: a winding wire, and both ends of the winding wire in the hollow solenoid are connected to the AC power supply; starting the alternating magnetic field generator, taking the time of starting the alternating magnetic field generator as the starting point, and recording the time in real time to obtain the heating time; using the started alternating magnetic field generator to perform eddy current heating operation on the magnetic field test sample, when the heating time reaches a preset heating time threshold, turning off the alternating magnetic field generator to obtain a magnetic field target sample; using an infrared thermometer to perform a temperature measurement operation on the magnetic field target sample to obtain a magnetic field induced temperature; using the second experimental temperature, the magnetic field induced temperature and the heating time threshold to calculate the temperature change rate, and the calculation formula is as follows:

[0015] ,in, is the temperature change rate, is the magnetic field induced temperature, is the temperature rise time threshold; the magnetic resistance induction rate is calculated using the temperature change rate and the magnet temperature change coefficient. The calculation formula is as follows:

[0016] ,in, is the magnetoresistance induction rate.

[0017] Optionally, the method of obtaining the high-temperature magnetic loss rate using the temperature test sample includes: using a pre-built fluxmeter to perform a detection operation on the temperature test sample to obtain an initial magnetic flux; starting a pre-built Helmholtz coil, and using the started Helmholtz coil to perform a magnetization operation on the temperature test sample to obtain a magnetization test sample; using the fluxmeter to perform a detection operation on the magnetization test sample to obtain a test magnetic flux, using the test magnetic flux and the initial magnetic flux to calculate the magnetization difference, and comparing the magnetization difference with a preset difference threshold; if the magnetization difference is greater than the difference threshold, then using the test magnetic flux as the initial magnetic flux, and using the magnetization test sample as the temperature test sample, and returning to the step of performing a magnetization operation on the temperature test sample using the started Helmholtz coil until the magnetization difference is less than or equal to the difference threshold; if the magnetization difference is less than or equal to the difference threshold, then using the magnetization test sample as the target test sample, and using the test magnetic flux as the target magnetic flux; obtaining a test temperature sequence, and extracting the first magnetic flux from the test temperature sequence. test temperatures, where the test temperature sequence contains Test temperature, The initial value is ,and ≤ ; Set the temperature of the pre-built vacuum baking oven to perform the baking operation Test temperature, get baking oven; using the The first baking oven performs a baking operation on the target test sample, and the Baking samples, The baked samples were subjected to natural cooling and the demagnetized samples; using a fluxmeter to The demagnetized samples are tested and the Temperature flux, the first Item is replaced by The temperature flux is obtained to obtain the updated baking series, where the baking test series is as follows:

[0018] ,in, is the first item in the baking test series. is the second item in the baking test series, For the baking test series Item; update the baking sequence as the baking test sequence, and demagnetized samples are used as target test samples, let I= +1, I as , returns the first Test temperature steps until I= +1, the updated baking sequence is used as the target baking sequence; the high temperature magnetic loss rate is calculated using the target baking sequence, and the calculation formula is as follows:

[0019] ,in, is the high temperature magnetic loss rate, is the target magnetic flux, Bake the first number in the target sequence The temperature flux, The number of temperature fluxes in the target bake series.

[0020] Optionally, the calculation formula of the magnetic temperature response coefficient is as follows:

[0021] ,in, is the magneto-thermal response coefficient, is the hyperbolic tangent function.

[0022] Optionally, the calculation formula of the magnetic energy balance efficiency is as follows:

[0023] ,in, is the magnetic energy balance efficiency, is a natural constant.

[0024] To achieve the above-mentioned purpose, the present invention also provides a sintered NdFeB magnet resistivity optimization system based on alumina doping, comprising: an NdFeB magnet acquisition module, used to acquire NdFeB magnetic powder and alumina powder, perform uniform sampling operation on a preset doping ratio range to obtain multiple doping ratios, and perform the following operations on each of the multiple doping ratios: obtain a NdFeB sample using the preset NdFeB mass and NdFeB magnetic powder, calculate the alumina mass using the NdFeB mass and the doping ratio, and calculate the alumina mass using the alumina mass and the alumina mass. Aluminum powder is used to obtain aluminum oxide samples, and a pre-built mixer is used to mix the aluminum oxide samples and NdFeB samples to obtain primary mixed magnetic powder, and the primary mixed magnetic powder is used to obtain NdFeB magnets; a magnet performance screening module is used to obtain magnet samples using NdFeB magnets, and a pre-built permanent magnet measuring instrument is used to perform a detection operation on the magnet samples to obtain a test remanence and a sample coercive force, compare the test remanence with a preset remanence threshold and compare the sample coercive force with a preset coercive force threshold, if the test remanence is greater than or equal to the remanence threshold and the sample If the coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet; the target magnet test module is used to summarize the target magnets to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: using the target magnet to obtain magnetic energy test samples, resistance test samples and temperature test samples, using the magnetic energy test samples to obtain the magnet energy efficiency product, using the resistance test samples to obtain the magnet resistivity and magnetoresistance induction rate, using the temperature test samples to obtain the high-temperature magnetic loss rate, and according to the high-temperature magnetic The magnetic temperature response coefficient is calculated based on the loss rate, magnetic resistance induction rate and magnet resistivity, and the magnetic energy balance efficiency is calculated based on the magnetic temperature response coefficient and the magnet energy efficiency product; the magnet production module is optimized to summarize the magnetic energy balance efficiencies, obtain multiple magnetic energy balance efficiencies, take the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies as the successful magnetic energy efficiency, take the doping ratio corresponding to the successful magnetic energy efficiency as the successful ratio, obtain the optimized NdFeB magnet based on NdFeB magnetic powder, alumina powder and the successful ratio, and complete the resistivity optimization of the sintered NdFeB magnet.

[0025] In order to solve the above problems, the present invention also provides an electronic device, which includes: a memory storing at least one instruction; and a processor executing the instructions stored in the memory to implement the above-mentioned method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping.

[0026] In order to solve the above problems, the present invention also provides a computer-readable storage medium, in which at least one instruction is stored. The at least one instruction is executed by a processor in an electronic device to implement the above-mentioned resistivity optimization method of sintered NdFeB magnets based on alumina doping.

[0027] The present invention is to solve the problem described in the background technology. The present invention obtains NdFeB magnetic powder and alumina powder, performs a uniform sampling operation on a preset doping ratio range, obtains multiple doping ratios, and performs the following operations on each of the multiple doping ratios: obtains a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculates the alumina mass using the NdFeB mass and the doping ratio, obtains an alumina sample using the alumina mass and the alumina powder, performs a mixing operation on the alumina sample and the NdFeB sample using a pre-built mixer to obtain a primary mixed magnetic powder, and obtains a NdFeB magnet using the primary mixed magnetic powder. It can be seen that the embodiment of the present invention improves the resistivity of the sintered NdFeB magnet by doping the alumina sample in the NdFeB sample, and A plurality of NdFeB magnets are manufactured using a plurality of different doping ratios, so as to facilitate subsequent testing of the plurality of NdFeB magnets respectively, screen out the best doping ratio, and then obtain a magnet sample using the NdFeB magnet, perform a detection operation on the magnet sample using a pre-built permanent magnet measuring instrument, obtain a test remanence and a sample coercive force, compare the test remanence with a preset remanence threshold, and compare the sample coercive force with a preset coercive force threshold; if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet. It can be seen that the embodiment of the present invention preliminarily screens out target magnets that meet the requirements by detecting the test remanence and sample coercive force of the magnet sample, thereby improving the accuracy of subsequent screening and saving testing costs. The target magnets are aggregated to obtain a plurality of target magnets, and the following operations are performed on each of the plurality of target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained by using the target magnets, a magnet energy efficiency product is obtained by using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained by using the resistance test sample, and a high-temperature magnetic loss rate is obtained by using the temperature test sample. It can be seen that the embodiment of the present invention tests the magnet energy efficiency product, magnet resistivity, magnetoresistance induction rate and high-temperature magnetic loss rate of the target magnet by using the magnetic energy test sample, the resistance test sample and the temperature test sample, so that the magnetic properties and resistivity of the target magnet can be comprehensively evaluated according to the magnet energy efficiency product, the magnet resistivity, the magnetoresistance induction rate and the high-temperature magnetic loss rate in the subsequent process, thereby improving the comprehensive evaluation of the NdFeB magnet. The magnetic temperature response coefficient is calculated according to the high-temperature magnetic loss rate, the magnetic resistance induction rate and the resistivity of the magnet. The magnetic energy balance efficiency is calculated according to the magnetic temperature response coefficient and the magnet energy efficiency product. It can be seen that the embodiment of the present invention balances the weights of the resistivity and magnetic properties of the target magnet by calculating the magnetic energy balance efficiency, and quantifies the comprehensive quality of the target magnet, so as to facilitate the subsequent use of the magnetic energy balance efficiency to screen out the best doping ratio, summarize the magnetic energy balance efficiency, and obtain multiple magnetic energy balance efficiencies. The largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, and the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio. Based on the NdFeB magnetic powder, the alumina powder and the successful ratio, the optimized NdFeB magnet is obtained, and the resistivity optimization of the sintered NdFeB magnet is completed.It can be seen that the embodiment of the present invention screens out the best success ratio through the magnetic energy balance efficiency, and then uses the success ratio to produce optimized NdFeB magnets, successfully optimizing the resistivity of sintered NdFeB magnets while improving the overall quality of NdFeB magnets. Therefore, the present invention can improve the resistivity of optimized NdFeB magnets and improve the overall quality of NdFeB magnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic flow chart of a method for optimizing the resistivity of a sintered NdFeB magnet based on aluminum oxide doping provided in one embodiment of the present invention; Figure 2 A functional module diagram of a resistivity optimization system for sintered NdFeB magnets based on alumina doping provided by one embodiment of the present invention; Figure 3 A schematic structural diagram of an electronic device for implementing the resistivity optimization method of sintered NdFeB magnets based on alumina doping provided in one embodiment of the present invention.

[0029] Explanation of the reference numerals: 1. electronic device; 10. processor; 11. memory; 12. bus.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0032] The embodiment of the present application provides a method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping. The execution subject of the method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided in the embodiment of the present application. In other words, the method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc.

[0033] Reference Figure 1As shown, it is a schematic flow chart of a method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping provided by one embodiment of the present invention. In this embodiment, the method for optimizing the resistivity of a sintered NdFeB magnet based on alumina doping includes: S1, obtaining NdFeB magnetic powder and alumina powder, performing a uniform sampling operation on a preset doping ratio range to obtain multiple doping ratios, and performing the following operations on each of the multiple doping ratios: obtaining a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculating the alumina mass using the NdFeB mass and the doping ratio, and obtaining an alumina sample using the alumina mass and the alumina powder.

[0034] For example, Xiao Zhang is a processor in a sintered NdFeB magnet factory. He now needs to optimize the resistivity of the sintered NdFeB magnet by doping with alumina, thereby improving the magnetic properties of the sintered NdFeB magnet. So Xiao Zhang tests multiple doping ratios of alumina, and then screens out the doping ratio suitable for optimizing the resistivity.

[0035] Optionally, MQP-B+-20444 B3+ magnetic powder is used as the NdFeB magnetic powder, and JWN-AO-3N-a20 3N high-purity alumina is used as the alumina powder.

[0036] Exemplarily, the doping ratio range is set to (0.1%-0.8%), and the sampling interval of the uniform sampling operation is set to 0.1%, then 8 doping ratios are obtained, namely 0.1%, 0.2%, ..., 0.8%.

[0037] It should be explained that the preset NdFeB mass is related to the mass of sintered NdFeB magnets that the factory expects to produce, and the mass of NdFeB is much smaller than the mass of NdFeB magnetic powder.

[0038] For example, if the mass of NdFeB is 100 g, 100 g of NdFeB magnetic powder is extracted as the NdFeB sample, and the doping ratio is 0.1%, then the mass of aluminum oxide is 0.1 g, and 0.1 g of aluminum oxide powder is extracted as the aluminum oxide sample.

[0039] S2. Using a pre-built mixer to mix the aluminum oxide sample and the NdFeB sample to obtain primary mixed magnetic powder, and using the primary mixed magnetic powder to obtain the NdFeB magnet.

[0040] It should be explained that the mixer is a machine used to mix the aluminum oxide sample and the NdFeB sample. Optionally, a Kede mechanical powder mixer is used as the mixer. The primary mixed magnetic powder refers to the mixed aluminum oxide sample and the NdFeB sample.

[0041] In detail, the method of obtaining NdFeB magnets using primary mixed magnetic powder includes: performing an airflow crushing operation on the primary mixed magnetic powder to obtain intermediate mixed magnetic powder, and extracting an intermediate magnetic powder sample from the intermediate mixed magnetic powder; performing a detection operation on the intermediate magnetic powder sample using a pre-built laser particle size analyzer to obtain a test magnetic powder particle size; comparing the test magnetic powder particle size with a preset magnetic powder particle size threshold, if the test magnetic powder particle size is greater than the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the primary mixed magnetic powder, and returning to the step of performing an airflow crushing operation on the primary mixed magnetic powder until the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold; if the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the target mixed magnetic powder; performing an orientation pressing operation on the target mixed magnetic powder to obtain a preliminary pressed magnetic block, performing a cold isostatic pressing operation on the preliminary pressed magnetic block to obtain a target pressed magnetic block; performing a vacuum sintering operation on the target pressed magnetic block to obtain a sintered magnetic block, and performing a graded tempering operation on the sintered magnetic block to obtain a NdFeB magnet.

[0042] It should be explained that the performing of airflow pulverizing operation on the primary mixed magnetic powder refers to: performing a pulverizing operation on the primary mixed magnetic powder using a pre-built airflow pulverizer. Optionally, Mianyang Jiufang airflow pulverizer JFQ-50 is used as the airflow pulverizer.

[0043] It should be understood that extracting the intermediate magnetic powder sample from the intermediate mixed magnetic powder means: extracting a certain mass of the intermediate mixed magnetic powder as the intermediate magnetic powder sample, and the mass of the intermediate magnetic powder sample is much smaller than the mass of the intermediate mixed magnetic powder.

[0044] It should be explained that the laser particle size analyzer is an instrument for measuring the particle size of the intermediate mixed magnetic powder. Optionally, the LT3600 laser particle size analyzer is used as the laser particle size analyzer. The magnetic powder particle size threshold is set by the processor based on the factory's historical data and production experience. Optionally, the magnetic powder particle size threshold is set to 3 microns.

[0045] Generally speaking, a laser particle size analyzer cannot accurately measure the particle size of each magnetic powder in the intermediate mixed magnetic powder, so the tested magnetic powder particle size is the average particle size of the intermediate mixed magnetic powder.

[0046] It should be understood that the orientation pressing operation performed on the target mixed magnetic powder refers to: using a pre-built magnetic field press to press the target mixed magnetic powder into a shape, wherein the magnetic field strength, magnetic field direction and pressing pressure of the magnetic field press are preset.

[0047] Optionally, the magnetic field strength of the magnetic field press is 2 Tesla, the magnetic field direction is vertically downward from the ground, and the pressing pressure is 100 MPa.

[0048] It should be explained that the magnetic field press is a press modified by adding an electromagnet to the molding press, which can apply a magnetic field with a fixed direction and stable magnetic field strength when pressing the target mixed magnetic powder. And the technology of using the pre-built magnetic field press to press the target mixed magnetic powder into shape is a prior art and will not be repeated here.

[0049] It should be understood that the cold isostatic pressing operation performed on the preliminary pressed magnetic block means: further pressing the preliminary pressed magnetic block using the cold isostatic pressing technology, and the cold isostatic pressing technology is a prior art and will not be described in detail here.

[0050] It should be explained that the vacuum sintering operation performed on the target pressed magnetic block refers to: using a pre-built vacuum sintering furnace to perform a sintering operation on the target pressed magnetic block, wherein the sintering temperature and sintering time of the vacuum sintering furnace are preset. Optionally, the sintering temperature is 1050 degrees Celsius and the sintering time is 5 hours. And the technology of performing a sintering operation on the target pressed magnetic block using a pre-built vacuum sintering furnace is a prior art and will not be repeated here.

[0051] In detail, the step of performing graded tempering on the sintered magnet block to obtain the NdFeB magnet includes: using a pre-built infrared thermometer to perform a temperature measurement operation on the sintered magnet block to obtain an initial magnet block temperature, taking the time of obtaining the initial magnet block temperature as the starting point and recording the time in real time to obtain a first cooling time; performing a natural cooling operation on the sintered magnet block, and using an infrared thermometer to monitor the sintered magnet block in the natural cooling operation in real time to obtain a real-time temperature; obtaining the current room temperature, when the real-time temperature reaches the current room temperature, using the sintered magnet block as the first cooling magnet block, and using the first cooling time to calculate the first insulation time, wherein the first insulation time is twice the first cooling time; using the current room temperature and the initial magnet block temperature to calculate the first stage temperature, the calculation formula is as follows:

[0052] ,in, is the current room temperature, is the initial magnet temperature, is the first stage temperature; the temperature at which the pre-constructed vacuum tempering furnace is heated and kept warm is set as the first stage temperature to obtain the first tempering furnace, and the first cooling magnetic block is heated and kept warm by the first tempering furnace to obtain the first insulation magnetic block, wherein the time for keeping the first cooling magnetic block warm is the first insulation time; the time for obtaining the first insulation magnetic block is taken as the starting point and the time is recorded in real time to obtain the second cooling time, and the second cooling magnetic block and the second insulation time are obtained based on the first insulation magnetic block and the second cooling time, and the second stage temperature is calculated based on the current room temperature and the first stage temperature; the NdFeB magnet is obtained based on the second cooling magnetic block, the second stage temperature and the second insulation time.

[0053] It should be explained that the initial magnet block temperature refers to the temperature of the sintered magnet block. Optionally, a SCIT-M separate infrared thermometer is used as the infrared thermometer.

[0054] It should be understood that the natural cooling operation on the sintered magnet block refers to: allowing the sintered magnet block to cool naturally in a stopped vacuum sintering furnace. The real-time temperature refers to the temperature of the sintered magnet block during the natural cooling operation.

[0055] Exemplarily, if the time to obtain the initial magnetic block temperature is 10:00, then at 10:10, the first cooling time is 10 minutes. Xiao Zhang obtains the current room temperature of 25 degrees Celsius by reading the reading of the thermometer on the indoor wall of the factory. When the real-time temperature is 25 degrees Celsius, the sintered magnetic block is used as the first cooling magnetic block, and the time at this time is read as 11:00, then the first cooling time is 1 hour, and the first insulation time is 2 hours. If the initial magnetic block temperature is 1000 degrees Celsius, the first stage temperature is calculated to be 650 degrees Celsius, so the first cooling magnetic block is placed in a vacuum tempering furnace, and the first cooling magnetic block is heated to 650 degrees Celsius in the vacuum tempering furnace, and kept at 650 degrees Celsius for 2 hours to obtain the first insulation magnetic block.

[0056] Optionally, a vacuum box furnace from Kere Furnace Industry is used as the vacuum tempering furnace.

[0057] It should be understood that the method of obtaining the second cooling magnet block and the second insulation time based on the first insulation magnet block and the second cooling time is the same as the method of obtaining the first cooling magnet block and the first insulation time using the sintered magnet block and the first cooling time. The method of obtaining the neodymium iron boron magnet based on the second cooling magnet block, the second stage temperature and the second insulation time is the same as the method of obtaining the first insulation magnet block using the first cooling magnet block, the first stage temperature and the first insulation time, and they will not be repeated here.

[0058] S3. Obtain a magnet sample using a neodymium iron boron magnet, perform a detection operation on the magnet sample using a pre-built permanent magnet measuring instrument to obtain a test remanent magnetism and a sample coercive force, compare the test remanent magnetism with a preset remanent magnetism threshold and compare the sample coercive force with a preset coercive force threshold; if the test remanent magnetism is greater than or equal to the remanent magnetism threshold and the sample coercive force is greater than or equal to the coercive force threshold, use the neodymium iron boron magnet corresponding to the magnet sample as the target magnet.

[0059] It should be understood that the method of obtaining a magnet sample using a NdFeB magnet means cutting a cube with a preset cutting length from the NdFeB magnet as the magnet sample, and the volume of the magnet sample is much smaller than the NdFeB magnet. Optionally, the cutting length is 5 cm.

[0060] It should be explained that the test remanence refers to the residual magnetization intensity of the magnet sample. The sample coercivity is the intrinsic coercivity of the magnet sample. Optionally, the FE-2100H-200 permanent magnet material measuring device is used as a permanent magnet measuring instrument, and the technology of using the pre-built permanent magnet measuring instrument to perform a detection operation on the magnet sample to obtain the test remanence and sample coercivity is a prior art and will not be repeated here.

[0061] For example, the factory expects that the sintered NdFeB magnets to be produced will be used in a certain motor, and the residual magnetization intensity of the NdFeB magnets required by the motor must be at least greater than 14.5kGS, and the intrinsic coercive force must be at least greater than 17.5kOe. Therefore, the residual magnetism threshold is set to 14.5kGS and the coercive force threshold is set to 17.5kOe.

[0062] S4. Summarize the target magnets to obtain multiple target magnets, and perform the following operations on each of the multiple target magnets: use the target magnets to obtain magnetic energy test samples, resistance test samples and temperature test samples, use the magnetic energy test samples to obtain the magnet energy efficiency product, use the resistance test samples to obtain the magnet resistivity and magnetoresistance induction rate, and use the temperature test samples to obtain the high-temperature magnetic loss rate.

[0063] It can be understood that the use of the target magnet to obtain the magnetic energy test sample, the resistance test sample and the temperature test sample means: cutting out three cubes with a side length equal to the cutting side length from the target magnet, using the cube used for subsequent testing of the magnet energy efficiency product as the magnetic energy test sample, using the cube used for subsequent testing of the magnet resistivity as the resistance test sample, and using the cube used for subsequent testing of the high-temperature magnetic loss rate as the temperature test sample, and the volumes of the magnetic energy test sample, the resistance test sample and the temperature test sample are all much smaller than the target magnet.

[0064] In detail, the method of obtaining the magnet energy efficiency product by using the magnetic energy test sample includes: performing a weighing operation on the magnetic energy test sample to obtain a test mass; performing a detection operation on the magnetic energy test sample by using a permanent magnet measuring instrument to obtain a test magnetic energy product and a test coercive force; calculating the magnet energy efficiency product by using the test remanence, sample coercive force, test coercive force, test mass and test magnetic energy product corresponding to the magnetic energy test sample, and the calculation formula is as follows:

[0065] ,in, is the magnet energy efficiency product, To test the residual magnetism, is the sample coercivity, To test the coercivity, To test the quality, To test the magnetic energy product, is the natural logarithm.

[0066] It should be explained that the test mass, test magnetic energy product and test coercive force refer to the mass, maximum magnetic energy product and coercive force of the magnetic energy test sample, respectively. And the technology of using a permanent magnetometer to perform a detection operation on the magnetic energy test sample to obtain the test magnetic energy product and test coercive force is a prior art and will not be repeated here.

[0067] It can be understood that the test remanence, sample coercive force and test coercive force all reflect the ability of the magnetic energy test sample to maintain magnetism, and the test magnetic energy product reflects the magnetic energy density of the magnetic energy test sample. Therefore, the magnetic energy efficiency product reflects the ability of the magnetic energy test sample to store and release magnetic energy per unit mass. The larger the magnetic energy efficiency product, the stronger the ability of the magnetic energy test sample to store and release magnetic energy per unit mass.

[0068] In detail, the method of using the resistance test sample to obtain the resistivity and magnetoresistance induction rate of the magnet includes: starting a pre-constructed constant temperature test box, setting the temperature of the constant temperature test box after starting to be the current room temperature, and obtaining a first constant temperature box; placing the resistance test sample in the first constant temperature box, taking the time when the resistance test sample is placed in the first constant temperature box as the starting point and recording the time in real time, and obtaining the constant temperature time, when the constant temperature time reaches a preset constant temperature time threshold, obtaining a first temperature measurement sample; performing a four-probe method test on the first temperature measurement sample in the first constant temperature box to obtain the resistivity of the magnet; updating the current room temperature corresponding to the first constant temperature box to a preset second experimental temperature, and obtaining a second constant temperature box, wherein the second experimental temperature is greater than the current room temperature; obtaining a second temperature measurement sample and a second resistivity based on the first temperature measurement sample and the second constant temperature box; calculating the magnet temperature variation coefficient using the current room temperature, the second experimental temperature, the magnet resistivity and the second resistivity, and the calculation formula is as follows:

[0069] ,in, is the temperature variation coefficient of the magnet, and are the magnet resistivity and the second resistivity, is the second experimental temperature; and the magnetoresistance induction rate is obtained using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample.

[0070] Optionally, an XH-THS-series constant temperature and humidity test chamber is used as the constant temperature test chamber.

[0071] Exemplarily, if the resistance test sample is placed in the first constant temperature box at 12:00 and the constant temperature time threshold is set to 30 minutes, then at 12:30, the resistance test sample in the first constant temperature box is used as the first temperature measurement sample.

[0072] It should be explained that the magnetic resistivity is the resistivity of the first temperature measurement sample. The four-probe method test on the first temperature measurement sample refers to: using the four-probe method to measure the resistivity of the first temperature measurement sample. And the technology of using the four-probe method to measure the resistivity of the first temperature measurement sample is an existing technology and will not be repeated here.

[0073] It is understandable that the second experimental temperature is greater than the current room temperature and less than or equal to the highest temperature that can be set in the constant temperature test box, and is set by the processor.

[0074] It should be understood that the method of obtaining the second temperature measurement sample and the second resistivity based on the first temperature measurement sample and the second constant temperature box is the same as the method of obtaining the first temperature measurement sample and the first resistivity using the resistance test sample and the first constant temperature box, and will not be repeated here.

[0075] It can be understood that the temperature variation coefficient of the magnet reflects the degree to which the resistivity of the resistance test sample is affected by temperature. The larger the temperature variation coefficient of the magnet, the more the resistivity of the resistance test sample is affected by temperature.

[0076] In detail, the method of obtaining the magnetic resistance induction rate by using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample includes: placing the second temperature measurement sample in a pre-constructed alternating magnetic field generator to obtain a magnetic field test sample, wherein the alternating magnetic field generator includes: an AC power supply and a hollow solenoid, wherein the hollow solenoid includes: a winding wire, and both ends of the winding wire in the hollow solenoid are connected to the AC power supply; starting the alternating magnetic field generator, taking the time of starting the alternating magnetic field generator as the starting point, and recording the time in real time to obtain the heating time; using the alternating magnetic field generator after starting to perform an eddy current heating operation on the magnetic field test sample, when the heating time reaches a preset heating time threshold, turning off the alternating magnetic field generator to obtain a magnetic field target sample; using an infrared thermometer to perform a temperature measurement operation on the magnetic field target sample to obtain a magnetic field induced temperature; using the second experimental temperature, the magnetic field induced temperature and the heating time threshold to calculate the temperature change rate, the calculation formula is as follows:

[0077] ,in, is the temperature change rate, is the magnetic field induced temperature, is the temperature rise time threshold; the magnetic resistance induction rate is calculated using the temperature change rate and the magnet temperature change coefficient. The calculation formula is as follows:

[0078] ,in, is the magnetoresistance induction rate.

[0079] It should be explained that the alternating magnetic field generator is a device that uses an alternating current power supply and a hollow solenoid to generate an alternating electromagnetic field. Optionally, a Beijing Cuihai CHL124-300 AC solenoid is used as the hollow solenoid. The heating time threshold is related to the frequency of the alternating current generated by the AC power supply and the model of the hollow solenoid, and is set by the processor.

[0080] It should be understood that the use of the started alternating magnetic field generator to perform eddy current heating on the magnetic field test sample means: using the alternating magnetic field generator to generate an alternating electromagnetic field, and causing the magnetic field test sample to generate eddy currents under the action of the alternating electromagnetic field, and due to the thermal effect of the current, the magnetic field test sample is gradually heated and heated under the action of the eddy currents.

[0081] It should be explained that the magnetic field induced temperature refers to the temperature of the magnetic field target sample. The temperature change rate reflects the rate at which the magnetic field test sample heats up under the action of the alternating electromagnetic field. The greater the temperature change rate, the faster the magnetic field test sample heats up under the action of the alternating electromagnetic field. The magnetoresistance induction rate refers to the rate at which the resistivity of the magnetic field test sample changes under the action of the alternating electromagnetic field, which in turn reflects the stability of the resistivity of the magnetic field test sample when it is disturbed by an external magnetic field. The greater the magnetoresistance induction rate, the worse the stability of the resistivity of the magnetic field test sample when it is disturbed by an external magnetic field.

[0082] In detail, the method of obtaining the high-temperature magnetic loss rate by using the temperature test sample includes: using a pre-built fluxmeter to perform a detection operation on the temperature test sample to obtain an initial magnetic flux; starting a pre-built Helmholtz coil, and using the started Helmholtz coil to perform a magnetization operation on the temperature test sample to obtain a magnetization test sample; using the fluxmeter to perform a detection operation on the magnetization test sample to obtain a test magnetic flux, using the test magnetic flux and the initial magnetic flux to calculate the magnetization difference, and comparing the magnetization difference with a preset difference threshold; if the magnetization difference is greater than the difference threshold, then using the test magnetic flux as the initial magnetic flux, and using the magnetization test sample as the temperature test sample, and returning to the step of performing a magnetization operation on the temperature test sample by using the started Helmholtz coil until the magnetization difference is less than or equal to the difference threshold; if the magnetization difference is less than or equal to the difference threshold, then using the magnetization test sample as the target test sample, and using the test magnetic flux as the target magnetic flux; obtaining a test temperature sequence, and extracting the first magnetic flux from the test temperature sequence. test temperatures, where the test temperature sequence contains Test temperature, The initial value is ,and ≤ ; Set the temperature of the pre-built vacuum baking oven to perform the baking operation Test temperature, get baking oven; using the The first baking oven performs a baking operation on the target test sample, and the Baking samples, The baked samples were subjected to natural cooling and the demagnetized samples; using a fluxmeter to The demagnetized samples are tested and the Temperature flux, the first Item is replaced by The temperature flux is obtained to obtain the updated baking series, where the baking test series is as follows:

[0083] ,in, is the first item in the baking test series. is the second item in the baking test series, For the baking test series Item; update the baking sequence as the baking test sequence, and demagnetized samples are used as target test samples, let I= +1, I as , returns the first Test temperature steps until I= +1, the updated baking sequence is used as the target baking sequence; the high temperature magnetic loss rate is calculated using the target baking sequence, and the calculation formula is as follows:

[0084] ,in, is the high temperature magnetic loss rate, is the target magnetic flux, Bake the first number in the target sequence The temperature flux, The number of temperature fluxes in the target bake series.

[0085] It should be explained that the initial magnetic flux refers to the magnetic flux of the temperature test sample. Optionally, a DSF-910 digital magnetic fluxmeter is used as a magnetic fluxmeter. The Helmholtz coil is a device that creates a uniform magnetic field in a small area.

[0086] Generally speaking, permanent magnets can be magnetized under the action of a stable external magnetic field, so the Helmholtz coil after startup can be used to perform a magnetization operation on the temperature test sample, wherein the magnetization time for the Helmholtz coil to perform a magnetization operation on the temperature test sample is preset, and the magnetization time is related to the magnetic field strength of the magnetic field generated by the Helmholtz coil, and is set by the processor. The technology of performing a magnetization operation on the temperature test sample using the Helmholtz coil after startup is a prior art and will not be repeated here.

[0087] It should be explained that the test flux refers to the magnetic flux of the magnetized test sample. Optionally, the difference threshold is set to 1× Wb.

[0088] It should be understood that when the magnetization difference is less than or equal to the difference threshold, it means that the magnetization test sample has been magnetized to the magnetic saturation state, so the magnetization test sample in the magnetic saturation state is used as the target test sample, and the target magnet refers to the test magnetic flux of the magnetization test sample in the magnetic saturation state.

[0089] For example, the test temperature sequence is: (30°C, 40°C, ..., 120°C), then the test temperature sequence contains 10 test temperatures. When the test temperature is extracted for the first time, =1, that is, the first test temperature is extracted from the test temperature sequence: 30°C, the temperature of the vacuum baking furnace for baking is set to 30°C, and the first baking furnace is obtained. The target test sample is baked in the first baking furnace for 2 hours to obtain the first baked sample. The first baked sample is naturally cooled to room temperature to obtain the first demagnetized sample. The first demagnetized sample is tested using a fluxmeter to obtain the first temperature flux of 1.5× Wb, replace the first item in the baking test series with 1.5× Wb, get the updated baking sequence as , then the baking sequence will be updated as the baking test sequence, the first demagnetization sample will be used as the target test sample, and I=1+1=2 will be calculated, so set The second test temperature is extracted from the test temperature sequence again, and the second temperature flux is obtained based on the second temperature, which is 1.3× Wb, then replace the second term in the baking test series with 1.3× Wb, get the updated baking sequence as , and so on, until I=11, and the updated baking sequence at this time is used as the target baking sequence.

[0090] It should be explained that the test temperature sequence is set by the processor based on the factory's historical data. For example, the temperature of the sintered NdFeB magnets produced by the factory will be in the range of 30℃ to 120℃ when actually put into use, so the test temperature sequence is set to (30℃, 40℃, ..., 120℃). A vacuum baking oven is a device that can set the baking temperature and bake the target test sample under vacuum. Optionally, a vacuum box furnace made by Kere Furnace Industry is used as the vacuum baking oven.

[0091] It should be understood that the high-temperature magnetic loss rate reflects the ease with which the magnetic flux of the target test sample is affected by temperature. The greater the high-temperature magnetic loss rate, the more easily the magnetic flux of the target test sample is affected by temperature, and the greater the loss rate of the magnetic flux of the target test sample under high temperature.

[0092] S5. Calculate the magnetic temperature response coefficient according to the high-temperature magnetic loss rate, the magnetic resistance induction rate and the magnet resistivity, and calculate the magnetic energy balance efficiency according to the magnetic temperature response coefficient and the magnet energy efficiency product.

[0093] In detail, the calculation formula of the magnetic temperature response coefficient is as follows:

[0094] ,in, is the magneto-thermal response coefficient, is the hyperbolic tangent function.

[0095] It should be understood that since the magnetic resistance induction rate reflects the stability of the resistivity of the magnetic field test sample when it is disturbed by an external magnetic field, and the high-temperature magnetic loss rate reflects the ease with which the magnetic flux of the target test sample is affected by temperature, the magnetic-temperature response coefficient reflects the ability of the magnetic field test sample and the target magnet corresponding to the target test sample to resist interference from external factors (such as temperature or magnetic field). The larger the magnetic-temperature response coefficient, the weaker the ability of the target magnet to resist interference from external factors, and the more susceptible it is to the influence of external factors.

[0096] In detail, the calculation formula of the magnetic energy balance efficiency is as follows:

[0097] ,in, is the magnetic energy balance efficiency, is a natural constant.

[0098] It should be understood that since the magnet energy efficiency product reflects the ability of the magnetic energy test sample to store and release magnetic energy per unit mass, and the magnetic-temperature response coefficient reflects the ability of the target magnet corresponding to the magnetic field test sample and the target test sample to resist interference from external factors, the magnetic energy balance efficiency is an indicator for comprehensively evaluating the magnetic properties of the target magnet, reflecting the ability of the magnetic field test sample, the target test sample and the target magnet corresponding to the magnetic energy test sample to store and release magnetic energy per unit mass under the influence of external factors. The greater the magnetic energy balance efficiency, the stronger the ability of the target magnet to store and release magnetic energy per unit mass under the influence of external factors, the better the performance of the target magnet, and the more in line with the expectations of factory production of sintered NdFeB magnets.

[0099] It should be understood that the embodiment of the present invention calculates the magnetic energy balance efficiency by performing a series of tests on magnetic field test samples, target test samples and magnetic energy test samples, so that the subsequent factory can screen out the doping ratio that best meets the factory's production expectations based on the magnetic energy balance efficiency, and then use the doping ratio for formal production.

[0100] S6. Summarize the magnetic energy balance efficiencies to obtain multiple magnetic energy balance efficiencies, take the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies as the successful magnetic energy efficiency, take the doping ratio corresponding to the successful magnetic energy efficiency as the successful ratio, obtain the optimized NdFeB magnet based on NdFeB magnetic powder, alumina powder and the successful ratio, and complete the resistivity optimization of the sintered NdFeB magnet.

[0101] It should be understood that the method for obtaining optimized NdFeB magnets based on NdFeB magnetic powder, alumina powder and a successful ratio is the same as the method for obtaining NdFeB magnets using NdFeB magnetic powder, alumina powder and a doping ratio, and will not be repeated here.

[0102] The present invention is to solve the problem described in the background technology. The present invention obtains NdFeB magnetic powder and alumina powder, performs a uniform sampling operation on a preset doping ratio range, obtains multiple doping ratios, and performs the following operations on each of the multiple doping ratios: obtains a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculates the alumina mass using the NdFeB mass and the doping ratio, obtains an alumina sample using the alumina mass and the alumina powder, performs a mixing operation on the alumina sample and the NdFeB sample using a pre-built mixer to obtain a primary mixed magnetic powder, and obtains a NdFeB magnet using the primary mixed magnetic powder. It can be seen that the embodiment of the present invention improves the resistivity of the sintered NdFeB magnet by doping the alumina sample in the NdFeB sample, and A plurality of NdFeB magnets are manufactured using a plurality of different doping ratios, so as to facilitate subsequent testing of the plurality of NdFeB magnets respectively, screen out the best doping ratio, and then obtain a magnet sample using the NdFeB magnet, perform a detection operation on the magnet sample using a pre-built permanent magnet measuring instrument, obtain a test remanence and a sample coercive force, compare the test remanence with a preset remanence threshold, and compare the sample coercive force with a preset coercive force threshold; if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet. It can be seen that the embodiment of the present invention preliminarily screens out target magnets that meet the requirements by detecting the test remanence and sample coercive force of the magnet sample, thereby improving the accuracy of subsequent screening and saving testing costs. The target magnets are aggregated to obtain a plurality of target magnets, and the following operations are performed on each of the plurality of target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained by using the target magnets, a magnet energy efficiency product is obtained by using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained by using the resistance test sample, and a high-temperature magnetic loss rate is obtained by using the temperature test sample. It can be seen that the embodiment of the present invention tests the magnet energy efficiency product, magnet resistivity, magnetoresistance induction rate and high-temperature magnetic loss rate of the target magnet by using the magnetic energy test sample, the resistance test sample and the temperature test sample, so that the magnetic properties and resistivity of the target magnet can be comprehensively evaluated according to the magnet energy efficiency product, the magnet resistivity, the magnetoresistance induction rate and the high-temperature magnetic loss rate in the subsequent process, thereby improving the comprehensive evaluation of the NdFeB magnet. The magnetic temperature response coefficient is calculated according to the high-temperature magnetic loss rate, the magnetic resistance induction rate and the resistivity of the magnet. The magnetic energy balance efficiency is calculated according to the magnetic temperature response coefficient and the magnet energy efficiency product. It can be seen that the embodiment of the present invention balances the weights of the resistivity and magnetic properties of the target magnet by calculating the magnetic energy balance efficiency, and quantifies the comprehensive quality of the target magnet, so as to facilitate the subsequent use of the magnetic energy balance efficiency to screen out the best doping ratio, summarize the magnetic energy balance efficiency, and obtain multiple magnetic energy balance efficiencies. The largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, and the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio. Based on the NdFeB magnetic powder, the alumina powder and the successful ratio, the optimized NdFeB magnet is obtained, and the resistivity optimization of the sintered NdFeB magnet is completed.It can be seen that the embodiment of the present invention screens out the best success ratio through the magnetic energy balance efficiency, and then uses the success ratio to produce optimized NdFeB magnets, successfully optimizing the resistivity of sintered NdFeB magnets while improving the overall quality of NdFeB magnets. Therefore, the present invention can improve the resistivity of optimized NdFeB magnets and improve the overall quality of NdFeB magnets.

[0103] like Figure 2 , which is a functional module diagram of a resistivity optimization system for sintered NdFeB magnets based on alumina doping provided by one embodiment of the present invention.

[0104] The resistivity optimization system 100 of the sintered NdFeB magnet based on alumina doping of the present invention can be installed in an electronic device. According to the functions to be implemented, the resistivity optimization system 100 of the sintered NdFeB magnet based on alumina doping can include a NdFeB magnet acquisition module 101, a magnet performance screening module 102, a target magnet testing module 103 and an optimized magnet production module 104. The module of the present invention can also be referred to as a unit, which refers to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, which are stored in the memory of the electronic device.

[0105] The NdFeB magnet acquisition module 101 is used to acquire NdFeB magnetic powder and alumina powder, perform uniform sampling operation on a preset doping ratio range to obtain multiple doping ratios, and perform the following operations on each of the multiple doping ratios: acquire a NdFeB sample using the preset NdFeB mass and NdFeB magnetic powder, calculate the alumina mass using the NdFeB mass and the doping ratio, acquire an alumina sample using the alumina mass and the alumina powder, and use a pre-built mixer to mix the alumina sample and the NdFeB sample. The present invention performs a mixing operation to obtain a primary mixed magnetic powder, and uses the primary mixed magnetic powder to obtain a NdFeB magnet; the magnet performance screening module 102 is used to obtain a magnet sample using the NdFeB magnet, and use a pre-built permanent magnet measuring instrument to perform a detection operation on the magnet sample to obtain a test remanence and a sample coercive force, compare the test remanence with a preset remanence threshold and compare the sample coercive force with a preset coercive force threshold, if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, then the magnet sample is correspondingly The NdFeB magnet is used as the target magnet; the target magnet testing module 103 is used to summarize the target magnets to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: using the target magnet to obtain a magnetic energy test sample, a resistance test sample and a temperature test sample, using the magnetic energy test sample to obtain the magnet energy efficiency product, using the resistance test sample to obtain the magnet resistivity and the magnet resistance induction rate, using the temperature test sample to obtain the high-temperature magnetic loss rate, calculating the magnetic temperature response coefficient according to the high-temperature magnetic loss rate, the magnet resistance induction rate and the magnet resistivity, and calculating the magnetic energy balance efficiency according to the magnetic temperature response coefficient and the magnet energy efficiency product; the optimized magnet production module 104 is used to summarize the magnetic energy balance efficiency to obtain multiple magnetic energy balance efficiencies, taking the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies as the successful magnetic energy efficiency, taking the doping ratio corresponding to the successful magnetic energy efficiency as the successful ratio, obtaining the optimized NdFeB magnet based on the NdFeB magnetic powder, the alumina powder and the successful ratio, and completing the resistivity optimization of the sintered NdFeB magnet.

[0106] In detail, each module in the alumina-doped sintered NdFeB magnet resistivity optimization system 100 in the embodiment of the present invention is used in the same manner as described above. Figure 1 The same technical means as the resistivity optimization method of sintered NdFeB magnets doped with alumina described in the text can produce the same technical effects, which will not be repeated here.

[0107] like Figure 3 , which is a schematic diagram of the structure of an electronic device for implementing a method for optimizing the resistivity of a sintered NdFeB magnet based on aluminum oxide doping provided by an embodiment of the present invention.

[0108] The electronic device 1 may include a processor 10, a memory 11 and a bus 12, and may also include a computer program stored in the memory 11 and executable on the processor 10, such as a method program for optimizing the resistivity of sintered NdFeB magnets based on aluminum oxide doping.

[0109] The memory 11 includes at least one type of readable storage medium, and the readable storage medium includes a flash memory, a mobile hard disk, a multimedia card, a card-type memory (for example, an SD or DX memory, etc.), a magnetic memory, a disk, an optical disk, etc. In some embodiments, the memory 11 may be an internal storage unit of the electronic device 1, such as a mobile hard disk of the electronic device 1. In other embodiments, the memory 11 may also be an external storage device of the electronic device 1, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 1. Further, the memory 11 also includes an internal storage unit of the electronic device 1 and an external storage device. The memory 11 can not only be used to store application software and various types of data installed in the electronic device 1, such as the code of the program of the resistivity optimization method of sintered NdFeB magnets doped with alumina, but also can be used to temporarily store data that has been output or is to be output.

[0110] The processor 10 may be composed of an integrated circuit in some embodiments, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips, etc. The processor 10 is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes or executes programs or modules (such as a method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping, etc.) stored in the memory 11, and calls data stored in the memory 11 to execute various functions of the electronic device 1 and process data.

[0111] The bus 12 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 12 may be divided into an address bus, a data bus, a control bus, etc. The bus 12 is configured to realize connection and communication between the memory 11 and at least one processor 10, etc.

[0112] Figure 3 Only an electronic device with components is shown, and those skilled in the art will understand that Figure 3 The structure shown does not constitute a limitation on the electronic device 1, and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0113] For example, although not shown, the electronic device 1 may also include a power source (such as a battery) for supplying power to various components. Preferably, the power source may be logically connected to the at least one processor 10 through a power management device, so that the power management device can realize functions such as charging management, discharging management, and power consumption management. The power source may also include one or more DC or AC power sources, recharging devices, power failure detection circuits, power converters or inverters, power status indicators, and other arbitrary components. The electronic device 1 may also include a variety of sensors, Bluetooth modules, Wi-Fi modules, etc., which will not be repeated here.

[0114] Furthermore, the electronic device 1 may also include a network interface. Optionally, the network interface may include a wired interface and / or a wireless interface (such as a WI-FI interface, a Bluetooth interface, etc.), which is generally used to establish a communication connection between the electronic device 1 and other electronic devices.

[0115] Optionally, the electronic device 1 may further include a user interface, which may be a display, an input unit (such as a keyboard), or a standard wired interface or a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch device. The display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the electronic device 1 and to display a visual user interface.

[0116] The program of the method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping stored in the memory 11 of the electronic device 1 is a combination of multiple instructions. When running in the processor 10, the following can be achieved: obtaining NdFeB magnetic powder and alumina powder, performing uniform sampling operations on a preset doping ratio range to obtain multiple doping ratios, and performing the following operations on each of the multiple doping ratios: obtaining NdFeB samples using the preset NdFeB mass and NdFeB magnetic powder, and using the NdFeB mass and doping ratio to obtain a NdFeB sample. The mass of aluminum oxide is calculated by proportion, and the aluminum oxide mass and aluminum oxide powder are used to obtain an aluminum oxide sample; a pre-built mixer is used to mix the aluminum oxide sample and the NdFeB sample to obtain a primary mixed magnetic powder, and a NdFeB magnet is obtained by using the primary mixed magnetic powder; a magnet sample is obtained by using the NdFeB magnet, and a pre-built permanent magnet measuring instrument is used to detect the magnet sample to obtain a test remanence and a sample coercive force, and the test remanence is compared with a preset remanence threshold and the sample coercive force is compared with a preset coercive force threshold; if the test If the remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet; the target magnets are summarized to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained using the target magnet, a magnet energy efficiency product is obtained using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained using the resistance test sample, and a high-temperature magnetic loss rate is obtained using the temperature test sample; a magneto-temperature response coefficient is calculated based on the high-temperature magnetic loss rate, the magnetoresistance induction rate and the magnet resistivity, and a magnetic energy balance efficiency is calculated based on the magneto-temperature response coefficient and the magnet energy efficiency product; the magnetic energy balance efficiencies are summarized to obtain multiple magnetic energy balance efficiencies, the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio, and an optimized NdFeB magnet is obtained based on the NdFeB magnetic powder, the alumina powder and the successful ratio, to complete the resistivity optimization of the sintered NdFeB magnet.

[0117] Specifically, the specific implementation method of the processor 10 for the above instructions can refer to Figures 1 to 3 The description of the relevant steps in the corresponding embodiments will not be repeated here.

[0118] Furthermore, if the module / unit integrated in the electronic device 1 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer-readable storage medium can be volatile or non-volatile. For example, the computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0119] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor of an electronic device, it can achieve the following: obtaining NdFeB magnetic powder and alumina powder, performing a uniform sampling operation on a preset doping ratio range to obtain multiple doping ratios, and performing the following operations on each of the multiple doping ratios: obtaining a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculating the alumina mass using the NdFeB mass and the doping ratio, and obtaining an alumina sample using the alumina mass and the alumina powder; performing a mixing operation on the alumina sample and the NdFeB sample using a pre-constructed mixer to obtain a primary mixed magnetic powder, and obtaining a NdFeB magnet using the primary mixed magnetic powder; obtaining a magnet sample using the NdFeB magnet, performing a detection operation on the magnet sample using a pre-constructed permanent magnet measuring instrument to obtain a test remanence and a sample coercive force, comparing the test remanence with a preset remanence threshold and comparing the sample coercive force with a preset coercive force threshold; if the test remanence is greater than If the remanence threshold is equal to the sample coercive force and the sample coercive force is greater than or equal to the coercive force threshold, the NdFeB magnet corresponding to the magnet sample is used as the target magnet; the target magnets are summarized to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained by using the target magnet, a magnet energy efficiency product is obtained by using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained by using the resistance test sample, and a high-temperature magnetic loss rate is obtained by using the temperature test sample; a magneto-temperature response coefficient is calculated according to the high-temperature magnetic loss rate, the magnetoresistance induction rate and the magnet resistivity, and a magnetic energy balance efficiency is calculated according to the magneto-temperature response coefficient and the magnet energy efficiency product; the magnetic energy balance efficiencies are summarized to obtain multiple magnetic energy balance efficiencies, the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio, and an optimized NdFeB magnet is obtained based on the NdFeB magnetic powder, the alumina powder and the successful ratio, so as to complete the resistivity optimization of the sintered NdFeB magnet.

[0120] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative, and actual implementation may have other division methods.

[0121] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0122] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0123] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping, characterized in that: The method comprises: obtaining NdFeB magnetic powder and alumina powder, performing a uniform sampling operation on a preset doping ratio range to obtain a plurality of doping ratios, and performing the following operations on each of the plurality of doping ratios: obtaining a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculating the alumina mass using the NdFeB mass and the doping ratio, and obtaining an alumina sample using the alumina mass and the alumina powder; performing a mixing operation on the alumina sample and the NdFeB sample using a pre-constructed mixer to obtain a primary mixed magnetic powder, and obtaining a NdFeB magnet using the primary mixed magnetic powder; obtaining a magnet sample using the NdFeB magnet, performing a detection operation on the magnet sample using a pre-constructed permanent magnet measuring instrument to obtain a test remanence and a sample coercive force, comparing the test remanence with a preset remanence threshold and comparing the sample coercive force with a preset coercive force threshold; if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, the magnet sample is removed. The corresponding NdFeB magnet is used as the target magnet; the target magnets are summarized to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: a magnetic energy test sample, a resistance test sample and a temperature test sample are obtained by using the target magnet, a magnet energy efficiency product is obtained by using the magnetic energy test sample, a magnet resistivity and a magnetoresistance induction rate are obtained by using the resistance test sample, and a high-temperature magnetic loss rate is obtained by using the temperature test sample; a magneto-temperature response coefficient is calculated according to the high-temperature magnetic loss rate, the magnetoresistance induction rate and the magnet resistivity, and a magnetic energy balance efficiency is calculated according to the magneto-temperature response coefficient and the magnet energy efficiency product; the magnetic energy balance efficiencies are summarized to obtain multiple magnetic energy balance efficiencies, the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies is used as the successful magnetic energy efficiency, the doping ratio corresponding to the successful magnetic energy efficiency is used as the successful ratio, an optimized NdFeB magnet is obtained based on the NdFeB magnetic powder, the alumina powder and the successful ratio, and the resistivity optimization of the sintered NdFeB magnet is completed.

2. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 1, characterized in that: The method of obtaining a NdFeB magnet using primary mixed magnetic powder includes: performing an airflow crushing operation on the primary mixed magnetic powder to obtain an intermediate mixed magnetic powder, and extracting an intermediate magnetic powder sample from the intermediate mixed magnetic powder; performing a detection operation on the intermediate magnetic powder sample using a pre-built laser particle size analyzer to obtain a test magnetic powder particle size; comparing the test magnetic powder particle size with a preset magnetic powder particle size threshold, if the test magnetic powder particle size is greater than the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the primary mixed magnetic powder, and returning to the step of performing an airflow crushing operation on the primary mixed magnetic powder until the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold; if the test magnetic powder particle size is less than or equal to the magnetic powder particle size threshold, using the intermediate mixed magnetic powder as the target mixed magnetic powder; performing an orientation pressing operation on the target mixed magnetic powder to obtain a preliminary pressed magnetic block, performing a cold isostatic pressing operation on the preliminary pressed magnetic block to obtain a target pressed magnetic block; performing a vacuum sintering operation on the target pressed magnetic block to obtain a sintered magnetic block, and performing a graded tempering operation on the sintered magnetic block to obtain a NdFeB magnet.

3. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 2, characterized in that: The step of performing graded tempering on the sintered magnet block to obtain the NdFeB magnet includes: using a pre-built infrared thermometer to perform a temperature measurement operation on the sintered magnet block to obtain an initial magnet block temperature, taking the time of obtaining the initial magnet block temperature as a starting point and recording the time in real time to obtain a first cooling time; performing a natural cooling operation on the sintered magnet block, and using an infrared thermometer to monitor the sintered magnet block in the natural cooling operation in real time to obtain a real-time temperature; obtaining the current room temperature, when the real-time temperature reaches the current room temperature, using the sintered magnet block as the first cooling magnet block, and using the first cooling time to calculate a first heat preservation time, wherein the first heat preservation time is twice the first cooling time; using the current room temperature and the initial magnet block temperature to calculate the first stage temperature, the calculation formula is as follows: ,in, is the current room temperature, is the initial magnet temperature, is the first stage temperature; the temperature at which the pre-constructed vacuum tempering furnace is heated and kept warm is set as the first stage temperature to obtain the first tempering furnace, and the first cooling magnetic block is heated and kept warm by the first tempering furnace to obtain the first insulation magnetic block, wherein the time for keeping the first cooling magnetic block warm is the first insulation time; the time for obtaining the first insulation magnetic block is taken as the starting point and the time is recorded in real time to obtain the second cooling time, and the second cooling magnetic block and the second insulation time are obtained based on the first insulation magnetic block and the second cooling time, and the second stage temperature is calculated based on the current room temperature and the first stage temperature; the NdFeB magnet is obtained based on the second cooling magnetic block, the second stage temperature and the second insulation time.

4. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 3, characterized in that: The method of obtaining the magnet energy efficiency product by using the magnetic energy test sample includes: performing a weighing operation on the magnetic energy test sample to obtain a test mass; performing a detection operation on the magnetic energy test sample by using a permanent magnet measuring instrument to obtain a test magnetic energy product and a test coercive force; and calculating the magnet energy efficiency product by using the test remanence, sample coercive force, test coercive force, test mass and test magnetic energy product corresponding to the magnetic energy test sample. The calculation formula is as follows: ,in, is the magnet energy efficiency product, To test the residual magnetism, is the sample coercivity, To test the coercivity, To test the quality, To test the magnetic energy product, is the natural logarithm.

5. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 4, characterized in that: The method of obtaining the magnet resistivity and magnetoresistance induction rate by using the resistance test sample includes: starting a pre-built constant temperature test box, setting the temperature of the constant temperature test box after starting to be the current room temperature, and obtaining a first constant temperature box; placing the resistance test sample in the first constant temperature box, taking the time when the resistance test sample is placed in the first constant temperature box as the starting point and recording the time in real time, and obtaining the constant temperature time, and obtaining the first temperature measurement sample when the constant temperature time reaches a preset constant temperature time threshold; performing a four-probe method test on the first temperature measurement sample in the first constant temperature box to obtain the magnet resistivity; updating the current room temperature corresponding to the first constant temperature box to a preset second experimental temperature, and obtaining a second constant temperature box, wherein the second experimental temperature is greater than the current room temperature; obtaining the second temperature measurement sample and the second resistivity based on the first temperature measurement sample and the second constant temperature box; calculating the magnet temperature variation coefficient by using the current room temperature, the second experimental temperature, the magnet resistivity and the second resistivity, and the calculation formula is as follows: ,in, is the temperature variation coefficient of the magnet, and are the magnet resistivity and the second resistivity, is the second experimental temperature; and the magnetoresistance induction rate is obtained using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample.

6. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 5, characterized in that: The method of obtaining the magnetic resistance induction rate by using the temperature variation coefficient of the magnet, the second experimental temperature and the second temperature measurement sample comprises: placing the second temperature measurement sample in a pre-constructed alternating magnetic field generator to obtain a magnetic field test sample, wherein the alternating magnetic field generator comprises: an alternating current power supply and a hollow solenoid, wherein the hollow solenoid comprises: a winding wire, and both ends of the winding wire in the hollow solenoid are connected to the alternating current power supply; starting the alternating magnetic field generator, taking the time of starting the alternating magnetic field generator as the starting point, and recording the time in real time to obtain the heating time; using the alternating magnetic field generator after starting to perform an eddy current heating operation on the magnetic field test sample, and when the heating time reaches a preset heating time threshold, turning off the alternating magnetic field generator to obtain a magnetic field target sample; using an infrared thermometer to perform a temperature measurement operation on the magnetic field target sample to obtain a magnetic field induced temperature; using the second experimental temperature, the magnetic field induced temperature and the heating time threshold to calculate the temperature change rate, and the calculation formula is as follows: ,in, is the temperature change rate, is the magnetic field induced temperature, is the temperature rise time threshold; the magnetic resistance induction rate is calculated using the temperature change rate and the magnet temperature change coefficient. The calculation formula is as follows: ,in, is the magnetoresistance induction rate.

7. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 6, characterized in that: The method of using a temperature test sample to obtain a high-temperature magnetic loss rate includes: using a pre-built fluxmeter to perform a detection operation on the temperature test sample to obtain an initial magnetic flux; starting a pre-built Helmholtz coil, and using the started Helmholtz coil to perform a magnetization operation on the temperature test sample to obtain a magnetization test sample; using a fluxmeter to perform a detection operation on the magnetization test sample to obtain a test magnetic flux, using the test magnetic flux and the initial magnetic flux to calculate a magnetization difference, and comparing the magnetization difference with a preset difference threshold; if the magnetization difference is greater than the difference threshold, using the test magnetic flux as the initial magnetic flux, using the magnetization test sample as the temperature test sample, and returning to the step of using the started Helmholtz coil to perform a magnetization operation on the temperature test sample until the magnetization difference is less than or equal to the difference threshold; if the magnetization difference is less than or equal to the difference threshold, using the magnetization test sample as a target test sample, and using the test magnetic flux as a target magnetic flux; obtaining a test temperature sequence, and extracting the first magnetic flux from the test temperature sequence. test temperatures, where the test temperature sequence contains Test temperature, The initial value is ,and ≤ ; Set the temperature of the pre-built vacuum baking oven to perform the baking operation Test temperature, get baking oven; using the The first baking oven performs a baking operation on the target test sample, and the Baking samples, The baked samples were subjected to natural cooling and the demagnetized samples; using a fluxmeter to The demagnetized samples are tested and the Temperature flux, the first Item is replaced by The temperature flux is obtained to obtain the updated baking series, where the baking test series is as follows: ,in, is the first item in the baking test series. is the second item in the baking test series, For the baking test series Item; update the baking sequence as the baking test sequence, and demagnetized samples are used as target test samples, let I= +1, I as , returns the first Test temperature steps until I= +1, the updated baking sequence is used as the target baking sequence; the high temperature magnetic loss rate is calculated using the target baking sequence, and the calculation formula is as follows: ,in, is the high temperature magnetic loss rate, is the target magnetic flux, Bake the first number in the target sequence The temperature flux, The number of temperature fluxes in the target bake series.

8. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 7, characterized in that: The calculation formula of the magnetic temperature response coefficient is as follows: ,in, is the magneto-thermal response coefficient, is the hyperbolic tangent function.

9. The method for optimizing the resistivity of sintered NdFeB magnets based on alumina doping according to claim 8, characterized in that: The calculation formula of the magnetic energy balance efficiency is as follows: ,in, is the magnetic energy balance efficiency, is a natural constant.

10. A resistivity optimization system for sintered NdFeB magnets doped with alumina, characterized in that: The system includes: a NdFeB magnet acquisition module, which is used to acquire NdFeB magnetic powder and alumina powder, perform uniform sampling operations on a preset doping ratio range to obtain multiple doping ratios, and perform the following operations on each of the multiple doping ratios: acquire a NdFeB sample using a preset NdFeB mass and NdFeB magnetic powder, calculate the alumina mass using the NdFeB mass and the doping ratio, acquire an alumina sample using the alumina mass and the alumina powder, and mix the alumina sample using a pre-built mixer. and NdFeB samples to perform a mixing operation to obtain primary mixed magnetic powder, and obtain NdFeB magnets using the primary mixed magnetic powder; a magnet performance screening module is used to obtain magnet samples using NdFeB magnets, perform a detection operation on the magnet samples using a pre-built permanent magnet measuring instrument, obtain a test remanence and a sample coercive force, compare the test remanence with a preset remanence threshold and compare the sample coercive force with a preset coercive force threshold, if the test remanence is greater than or equal to the remanence threshold and the sample coercive force is greater than or equal to the coercive force threshold, the magnet sample is removed. The corresponding NdFeB magnet is used as the target magnet; a target magnet testing module is used to summarize the target magnets to obtain multiple target magnets, and the following operations are performed on each of the multiple target magnets: using the target magnet to obtain magnetic energy test samples, resistance test samples and temperature test samples, using the magnetic energy test samples to obtain the magnet energy efficiency product, using the resistance test samples to obtain the magnet resistivity and magnetoresistance induction rate, using the temperature test samples to obtain the high-temperature magnetic loss rate, calculating the magnetic temperature response coefficient according to the high-temperature magnetic loss rate, magnetoresistance induction rate and magnet resistivity, and calculating the magnetic energy balance efficiency according to the magnetic temperature response coefficient and the magnet energy efficiency product; an optimized magnet production module is used to summarize the magnetic energy balance efficiency to obtain multiple magnetic energy balance efficiencies, taking the largest magnetic energy balance efficiency among the multiple magnetic energy balance efficiencies as the successful magnetic energy efficiency, taking the doping ratio corresponding to the successful magnetic energy efficiency as the successful ratio, obtaining the optimized NdFeB magnet based on the NdFeB magnetic powder, alumina powder and the successful ratio, and completing the resistivity optimization of the sintered NdFeB magnet.

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