Magnetic material, preparation thereof and rotor, thermal management system
By coating the surface of magnetic alloy powder with a composite coating layer, the performance degradation problem of magnetic materials under water and oxygen erosion was solved, enabling stable use in the thermal management system of new energy vehicles.
Patent Information
- Application Number
- CN202411603930.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2026-05-15
- Estimated Expiration
- 2044-11-12
AI Technical Summary
Magnetic materials are easily corroded by water and oxygen in the processing and use environment, which leads to the degradation of magnetic properties and processing performance, making it difficult to meet the requirements of thermal management systems for new energy vehicles.
A composite coating layer, consisting of a porous phosphate layer and a polycatechol ethylamine layer, is applied to the surface of magnetic alloy powder. These layers are connected by chemical bonds to form a dense and robust composite coating layer, which enhances corrosion resistance and processing performance.
It improves the corrosion resistance and processing performance of magnetic materials, meeting the magnet requirements of thermal management systems for new energy vehicles, especially the stability and magnetic properties under high-temperature environments.
Smart Images
Figure CN119495483B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of bonding magnetic materials technology, and in particular to magnetic materials and their preparation methods, rotors and thermal management systems. Background Technology
[0002] With the rapid development of the manufacturing industry, China's automotive industry faces challenges such as industrial transformation, emission reduction, energy crisis, and low-carbon development. Developing new energy vehicles has become an important way to reduce the automotive industry's dependence on oil and exhaust pollution. In new energy vehicles, components such as engines and transmissions are replaced by batteries, motors, electronic controls, and reducers. The magnets in key components of the thermal management system are made of magnetic materials, and the thermal management system has high requirements for the comprehensive performance of magnetic materials.
[0003] Magnetic materials are easily corroded by water and oxygen in the processing and use environment, resulting in a decline in their magnetic properties and processing performance. Furthermore, the problem of easy degradation of magnetic properties and processing performance still exists in related technologies. Therefore, there is an urgent need to improve existing magnetic materials. Summary of the Invention
[0004] The first objective of this invention is to address the shortcomings of existing technologies by providing a magnetic material in which a composite coating layer is applied to at least a portion of the surface of a magnetic alloy powder; wherein,
[0005] The composite coating layer includes a first coating layer containing -P(O)- structural segments and a coating layer containing... The second coating layer of the structural fragment, the -P(O)- structural fragment, is chemically bonded to the metal atoms on the surface of the magnetic alloy powder.
[0006] Furthermore, the first coating layer has a porous structure; even further, the second coating layer covers the outside of the first coating layer and is at least partially interpenetrated and fixed within the porous structure of the first coating layer.
[0007] Furthermore, the material of the first coating layer is phosphate.
[0008] Furthermore, the material of the second coating layer is polycatechol ethylamine.
[0009] Furthermore, the magnetic material is in powder form.
[0010] Furthermore, the magnetic alloy powder is selected from at least one of neodymium iron boron alloy powder, samarium iron nitrogen alloy powder, and samarium cobalt alloy powder.
[0011] Furthermore, a magnetic composite material includes the aforementioned magnetic material and an adhesive layer, wherein the adhesive layer is disposed on at least a portion of the surface of the magnetic material; the adhesive layer comprises a resin polymer and a polymeric elastomer dispersed in the resin polymer.
[0012] Furthermore, the content of the magnetic material is 83–93 wt.%, and the content of the adhesive layer is 7–17 wt.%.
[0013] Furthermore, the resin polymer is polyphenylene sulfide or polyamide.
[0014] Furthermore, the polymeric elastomer is located between the particles of the magnetic material and is dispersed together with them in the resin polymer adhesive layer.
[0015] Furthermore, the polymeric elastomer is selected from at least one of glycidyl methacrylate-grafted EPDM rubber and glycidyl methacrylate-grafted hydrogenated styrene-butadiene block copolymer.
[0016] Furthermore, the magnetic composite material is in granular form.
[0017] A second objective of this invention is to provide a method for preparing the above-mentioned magnetic material, comprising the following steps:
[0018] A compound containing a -P(O)- structural fragment is dissolved in an organic solvent, which may be ethanol, isopropanol, or a mixture of both; magnetic powder is immersed in the solvent and stirred until it is fully in contact with the solution. After soaking at room temperature for 1 to 24 hours, it is dried under vacuum or a non-reactive protective atmosphere to obtain a magnetic alloy powder coated with a first coating layer (porous phosphate), wherein the -P(O)- structural fragment is chemically bonded to the metal atoms on the surface of the magnetic alloy powder.
[0019] Will contain A precursor solution is obtained by dissolving a small molecule compound with a functional group in an aqueous solution. The magnetic alloy powder material with the first coating layer is then immersed in the solution and stirred for 0.5–12 hours, maintaining a temperature of 40–60°C. Triethanolamine or ammonia is added dropwise to maintain the pH value at 7.2–10.5. After filtration and rinsing with organic solvents such as ethanol and isopropanol to remove moisture, the powder is dried under vacuum or a non-reactive protective atmosphere to obtain a magnetic alloy powder material with a second coating layer (polycatechol ethylamine). This coating layer contains [missing information - likely related to polymerization process]. Small molecule compounds with functional groups enter the porous structure of the first coating layer and polymerize therein into a polycatechol ethylamine macromolecule. This results in the second coating layer, after polymerization, being at least partially intercalated and fixed within the porous structure of the first coating layer, thus filling and sealing the porous structure of the first coating layer to make it dense. This yields the magnetic material described in this invention.
[0020] The magnetic material described in this invention (i.e., magnetic alloy powder with at least a partial surface coating of a composite layer), resin polymer, and high-molecular elastomer are placed in a mixer in a certain proportion and mixed evenly to form a mixture; then the mixture is added to a screw extruder for kneading and granulation. This yields the magnetic composite material.
[0021] A third object of the present invention is to provide a rotor comprising the aforementioned magnetic material or the aforementioned magnetic composite material.
[0022] A fourth object of the present invention is to provide a thermal management system comprising at least one of a pump, a valve, and a cooling device, wherein at least one of the pump, the valve, and the cooling device comprises the aforementioned magnetic material or the aforementioned magnetic composite material.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0024] This invention involves coating a magnetic alloy powder with a composite coating layer. The first coating layer is chemically bonded to the surface of the magnetic alloy powder, providing strong adhesion and is porous. The second coating layer is at least partially intercalated and polymerized within the porous structure of the first coating layer, thus firmly bonding with it and sealing its pores to make it dense. This effectively solves the problem of magnetic property and processing performance degradation during the processing and use of related magnetic materials. Simultaneously, it improves the processability, magnetic properties, mechanical properties, and environmental stability of the magnetic material, meeting the injection molding requirements of magnets used in the thermal management systems of new energy vehicles. Attached Figure Description
[0025] Figure 1 A schematic diagram of one embodiment of the magnetic material with a composite coating layer in this application;
[0026] Figure 2 This is a schematic diagram of a structural embodiment of the magnetic composite material including a resin polymer adhesive layer in this application;
[0027] Explanation of reference numerals in the attached figures: 1. Magnetic alloy powder; 2. First coating layer; 3. Second coating layer; 4. Magnetic material; 5. Resin polymer adhesive layer; 6. Polymer elastomer. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Based on the technical solutions and embodiments provided in this application, all other technical solutions obtained by those skilled in the art without inventive effort are within the scope of protection of this application. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used in this application whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0029] The endpoints and any values of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges or individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges.
[0030] In related technologies, magnetic materials generally suffer from degradation in magnetic properties, processing performance, and mechanical strength due to extrusion processing, injection molding of magnetic devices, and susceptibility to corrosion from water and oxygen in the operating environment. This significantly limits their application in thermal management system magnets, especially in the thermal management systems of new energy vehicles. To address these shortcomings, a single phosphating protection measure is typically used to improve the oxidation resistance of magnetic alloy powders. However, phosphating protective films usually contain porous structures, making it difficult to achieve dense protection. Furthermore, the poor compatibility between inorganic phosphates and organic resin bonding layers leads to deterioration in magnetic properties and processing performance. Reinforcing and modifying the resin polymer bonding layer with inorganic materials such as carbon fiber, glass fiber, and carbon nanotubes also degrades the processing performance of magnetic materials, and may even prevent the injection molding of magnets.
[0031] This application provides a magnetic material, one form of which is magnetic material 4, such as... Figure 1 As shown, it includes magnetic alloy powder 1, a first coating layer 2 (covering at least a portion of the surface of the magnetic alloy powder 1, porous), and a second coating layer 3 (covering the outside of the first coating layer 2, and at least partially inserted and fixed within the porous structure of the first coating layer), wherein:
[0032] The first coating layer 2 is a compound containing a -P(O)- structural fragment, and the second coating layer 3 is a compound containing... The compound is a structural fragment; further, in some embodiments, the first coating layer is a phosphate and the second coating layer is polycatechol ethylamine.
[0033] In some embodiments, the first coating layer 2 and the second coating layer 3 are collectively referred to as a composite coating layer. The first coating layer is applied to at least a portion of the surface of the magnetic alloy powder, and the second coating layer is applied to at least a portion of the surface of the first coating layer and is interposed and fixed therein.
[0034] In some embodiments, the first coating layer 2 has a porous structure with pores, which increases the specific surface area of the magnetic alloy powder and provides a fixing point for the second coating layer; the second coating layer 3 is at least partially inserted and fixed within the porous structure of the first coating layer 2.
[0035] This application provides a magnetic composite material in granular form, such as... Figure 2 As shown, the device includes magnetic material 4, a resin polymer binder layer 5, and a polymer elastomer 6; the magnetic material 4 and the polymer elastomer 6 are dispersed within the resin polymer binder layer 5. During the injection molding process, the polymer binder layer serves to bond the magnetic material into shape, while the polymer elastomer provides toughening and improves mechanical properties without affecting magnetic properties.
[0036] In this application, the first coating layer containing the -P(O)- structural fragment compound, namely the phosphate layer, has good heat resistance and corrosion resistance, and is strongly bonded to the surface of the magnetic alloy powder 1. Although it is porous and difficult to densify, the porosity of this first coating layer increases the specific surface area of the magnetic alloy powder 1, thereby increasing the surface area of the magnetic alloy powder 1. Compounds containing -P(O)- structural fragments are intercalated and polymerized within the pores of the first coating layer containing -P(O)- structural fragments, thereby forming a dense and firmly bonded composite coating layer. In other words, on one hand, the first coating layer containing -P(O)- structural fragments is chemically bonded to the magnetic alloy powder 1, making the first coating layer very strong; on the other hand, the porosity of the first coating layer containing -P(O)- structural fragments increases the specific surface area of the magnetic alloy powder 1, making the first coating layer very strong. The compounds of the structural fragments are firmly intercalated and polymerized on the outside of the magnetic alloy powder 1, and the pores of the first coating layer are sealed. The two work together to form a strong and dense composite coating layer, which effectively isolates the corrosion of water and oxygen, and improves the performance and stability of the magnetic material.
[0037] In this application, the chemical structural formula of polycatechol ethylamine is:
[0038] In some embodiments, the magnetic material can be in powder form, with at least a portion of the surface of the powdered magnetic alloy covered by a composite coating layer; the magnetic material can also be in granular form, which is a magnetic composite material including a resin binder layer and a polymer elastomer and presenting as discrete granules, with the polymer elastomer located between the powdered magnetic material particles and dispersed together with them in the resin binder layer; the magnetic material can also be in bulk form, i.e., a magnet, presenting as a state in which the particles are melted and reassembled into the shape required by the rotor and the magnetic devices of the thermal management system.
[0039] In some embodiments, the content of the magnetic material 4 (magnetic alloy powder with at least a composite coating layer on its surface) described in this invention is 83-93 wt.%, specifically selected from 84 wt.%, 84.5 wt.%, 85 wt.%, 85.5 wt.%, 86.5 wt.%, 87 wt.%, 87.5 wt.%, 88 wt.%, 88.5 wt.%, 89 wt.%, 89.5 wt.%, 90 wt.%, 90.5 wt.%, 91 wt.%, 91.5 wt.%, 92 wt.%, and 92.5 wt.%, or other values within the range. It can be selected according to actual needs and is not limited here.
[0040] In some embodiments, the content of the resin polymer layer 5 is 7 to 17 wt.%, specifically selected from 7.0 wt.%, 7.5 wt.%, 8 wt.%, 8.5 wt.%, 9 wt.%, 9.5 wt.%, 10 wt.%, 10.5 wt.%, 11 wt.%, 11.5 wt.%, 12 wt.%, 12.5 wt.%, 13 wt.%, 13.5 wt.%, 14 wt.%, 14.5 wt.%, 15 wt.%, 15.5 wt.%, 16 wt.%, 16.5 wt.%, and 17 wt.%, or other values within the range. The selection can be made according to actual needs and is not limited here.
[0041] In some embodiments, the content of polymeric elastomer 6 is 0.3 to 2 wt.%, specifically selected from 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1.0 wt.%, 1.2 wt.%, 1.4 wt.%, 1.6 wt.%, 1.8 wt.%, 2.0 wt.%, or other values within the range. The selection can be made according to actual needs and is not limited here.
[0042] This application also provides a method for preparing a magnetic material, comprising the following steps:
[0043] A compound containing a -P(O)- structural fragment is dissolved in an organic solvent, which may be ethanol, isopropanol, or a mixture of both; magnetic powder is immersed in the solvent and stirred until it is fully in contact with the solution. After soaking at room temperature for 1 to 24 hours, it is dried under vacuum or a non-reactive protective atmosphere to obtain a magnetic alloy powder material coated with a first coating layer (porous phosphate), wherein the -P(O)- structural fragment is chemically bonded to the metal atoms on the surface of the magnetic alloy powder.
[0044] Will contain A small molecule compound with a certain functional group is dissolved in pure water to obtain a precursor aqueous solution. Magnetic alloy powder material with a first coating layer is immersed in this solution and stirred for 0.5–12 hours, maintaining a temperature of 40–60°C. Triethanolamine or ammonia is added dropwise to maintain the pH value at 7.2–10.5. After filtration and rinsing with organic solvents such as ethanol, the powder is vacuum dried to obtain a magnetic alloy powder material with a second coating layer (polycatechol ethylamine). This coating layer contains [missing information - likely a specific component or process] during polymerization. Small molecule compounds of the group enter the porous structure of the first coating layer and polymerize therein into a polycatechol ethylamine macromolecule. This results in the second coating layer, after polymerization, at least partially intercalating and fixing itself within the porous structure of the first coating layer, filling and sealing the porous structure of the first coating layer to make it dense. This leads to the acquisition of the magnetic material.
[0045] The magnetic material (i.e., magnetic alloy powder with at least a partial surface coating of a composite layer), resin binder, polymer elastomer, and other raw materials obtained in the previous step are placed in a mixer and mixed evenly to form a mixture; the mixture is then added to a screw extruder for kneading and granulation. This yields the aforementioned magnetic composite material.
[0046] In some embodiments, the first coating layer 2 comprises a compound containing a -P(O)- structural segment, and further, the compound containing the -P(O)- structural segment is a phosphate; the second coating layer 3 comprises a compound containing... Compounds containing structural fragments, further, contain The compound with the structural fragment is polycatechol ethylamine.
[0047] In this application, the chemical structural formula of polycatechol ethylamine is as follows: The reaction pathway is as follows:
[0048]
[0049] In some embodiments, the composite coating layer includes a first coating layer 2 and a second coating layer 3. The first coating layer includes phosphate, and the second coating layer includes polycatechol ethylamine. The first coating layer is applied to at least a portion of the surface of the magnetic alloy powder, and the second coating layer is applied to the outside of the first coating layer and is at least partially intercalated and fixed within the first coating layer.
[0050] In this application, the first coating layer containing the -P(O)- structural fragment compound, namely the phosphate layer, has good heat resistance and corrosion resistance, and is firmly bonded to the surface of the magnetic alloy powder 1 in the form of strong chemical structural fragment linkages. Although it is porous and difficult to densify, this first coating layer can make the magnetic alloy powder 1 contain... The compounds containing structural fragments interpenetrate, polymerize, and fix themselves within the pores, thereby forming a dense and robust composite coating layer. In other words, on one hand, the first coating layer containing the -P(O)- structural fragment compound is connected to the magnetic alloy powder 1 via chemical structural fragments, making the first coating layer very strong; on the other hand, the porosity of the first coating layer containing the -P(O)- structural fragment compound increases the specific surface area of the magnetic alloy powder 1 and strengthens the composite coating layer containing the -P(O)- structural fragment compound. The compound of the structural fragments is firmly bonded to the surface of the magnetic alloy powder 1 and seals the pores of the first coating layer, increasing the bonding force of the second coating layer. The two work together to form a strong and dense composite coating layer, which effectively isolates the corrosion of water and oxygen, effectively improves the processing performance of the magnetic material, and reduces the attenuation of magnetic properties during processing and use. At the same time, the inorganic surface of the magnetic alloy powder becomes the organic surface of the second coating layer, which improves the compatibility between the magnetic alloy powder and the resin adhesive layer.
[0051] In some embodiments, the phosphoric acid content in the phosphoric acid solution is 0.5 to 3.0 wt.%, specifically selected from 0.5 wt.%, 0.6 wt.%, 0.8 wt.%, 1.0 wt.%, 1.2 wt.%, 1.4 wt.%, 1.6 wt.%, 1.8 wt.%, 2.0 wt.%, 2.2 wt.%, 2.4 wt.%, 2.8 wt.%, and 3.0 wt.%, or other values within the range. The selection can be made according to actual needs and is not limited here.
[0052] In some embodiments, the solvent for the phosphoric acid solution is ethanol, specifically a phosphoric acid ethanol solution; the first coating layer is a porous phosphate coating layer, i.e., a first coating layer containing a compound with a -P(O)- structural fragment.
[0053] In some embodiments, the mass ratio of magnetic alloy powder to ethanolic phosphoric acid solution is 5:(0.5-3), and a first coating layer containing a compound with a -P(O)- structure fragment is formed on the powder surface. On the one hand, the first coating layer containing the -P(O)- structure fragment is chemically bonded to the magnetic alloy powder, making the first coating layer very strong; on the other hand, the porosity of the first coating layer containing the -P(O)- structure fragment increases the specific surface area of the magnetic alloy powder.
[0054] In some embodiments, the solvent of the catechol ethylamine solution is water, specifically an aqueous solution of catechol ethylamine, wherein the mass ratio of the magnetic alloy powder with at least a portion of its surface coated with a first coating layer to the catechol ethylamine solution is 5:(0.5-3).
[0055] In some embodiments, the content of catechol ethylamine in the catechol ethylamine solution is 2-10 wt.%, specifically selected from 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, or other values within the range, which can be selected according to actual needs and are not limited here; catechol ethylamine is a catechol natural substance with many functional groups (hydroxyl, amino, catechol group, etc.) on its surface, and can self-polymerize under alkaline conditions to form polycatechol ethylamine.
[0056] In some implementations, the pH adjustment value ranges from 7.2 to 10.5, specifically selected from 7.3, 7.5, 7.7, 7.9, 8.1, 8.3, 8.5, 8.7, 8.9, 9.1, 9.3, 9.5, 9.7, 9.9, 10.1, and 10.3, or other values within the range. The selection can be made according to actual needs and is not limited here.
[0057] In some embodiments, the method for preparing the magnetic composite material further includes the following steps:
[0058] We provide resin polymers and high molecular weight elastomers;
[0059] The magnetic material of the present invention (i.e., magnetic alloy powder with at least a partial surface coated with a composite coating), resin polymer, and polymer elastomer are placed in a mixer and mixed evenly to form a mixture.
[0060] The mixture is added to a screw extruder, and after mixing and granulation, a magnetic composite material is formed.
[0061] It should be noted that "wt.%" in this application means mass percentage or weight percentage; "parts by weight" refers to the basic unit of measurement for the weight ratio of multiple components. One part can represent any unit mass, such as 1g, 1.8g, or 5g, etc.
[0062] In some embodiments, the resin polymer is selected from polyphenylene sulfide or polyamide; the polymeric elastomer can be selected from at least one of glycidyl methacrylate-grafted EPDM rubber and glycidyl methacrylate-grafted hydrogenated styrene-butadiene block copolymer; by using a polymeric elastomer modified with active groups, the interfacial tension between raw materials can be effectively reduced, which is beneficial to the dispersion of the magnetic material and the elastomer in the resin polymer layer, improving the interfacial compatibility between raw materials, thereby ensuring the mechanical properties of the magnetic material; enabling it to meet the injection molding requirements of magnetic devices involved in thermal management systems, especially thermal management systems for new energy vehicles; in addition, the preparation method of the magnetic material in this application can be achieved by soaking and coating the surface of magnetic alloy powder, mixing, kneading and granulating, under mild conditions, with simple process, low equipment requirements, convenient operation and control, which is conducive to stable product quality and suitable for industrial mass production.
[0063] In some embodiments, when the resin binder is polyphenylene sulfide, the mixing temperature is 280–350°C, specifically selected from 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or other values within the range. The selection is made according to actual needs and is not limited here. When the resin binder is polyamide, the mixing temperature is 200–250°C, specifically selected from 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or other values within the range. The selection is made according to actual needs and is not limited here.
[0064] This application also provides a rotor, which may be made of magnetic material 4, or a magnetic composite material comprising magnetic material 4 (composed of magnetic alloy powder 1, first coating layer 2, and second coating layer 3), resin binder 5, and polymer elastomer 6.
[0065] The first coating layer 2 comprises a compound containing a -P(O)- structural fragment; the second coating layer 3 comprises a compound containing... The compound is composed of structural fragments and is intercalated and polymerized within the pores of the first coating layer 2.
[0066] Furthermore, compounds containing the -P(O)- structural segment are phosphates, containing The compound with the structural fragment is polycatechol ethylamine.
[0067] In this application, the first coating layer containing the -P(O)- structural fragment compound, namely the phosphate layer, has good heat resistance and corrosion resistance, and is firmly bonded to the surface of the magnetic alloy powder in the form of strong chemical structural fragment linkages. Although it is porous and difficult to densify, the porosity of this first coating layer increases the specific surface area of the magnetic alloy powder, thereby making the powder more resistant to corrosion. The compound containing the -P(O)- structural fragments is intercalated within the pores of the first coating layer containing the -P(O)- structural fragments, thereby forming a dense and robust composite coating layer. In other words, on one hand, the first coating layer containing the -P(O)- structural fragments is chemically bonded to the magnetic alloy powder, making the first coating layer very strong; on the other hand, the porosity of the first coating layer containing the -P(O)- structural fragments increases the specific surface area of the magnetic alloy powder, making the first coating layer very strong. The compound of the structural fragments is firmly bonded to the surface of the magnetic alloy powder and seals the pores of the first coating layer. The two work together to form a strong and dense composite coating layer, which effectively isolates the corrosion of water and oxygen, thereby meeting the usage requirements of magnets (such as rotors) involved in the thermal management system of new energy vehicles, especially the new energy thermal management system. It should be noted that this application is for the design of magnetic materials in the thermal management system, especially the rotors in water pumps, oil pumps, throttle valves, water valves and cooling devices. The performance requirements of magnetic materials in the thermal management system are: (1) After high temperature accelerated environment test (300℃, 24h) according to GB / T3217-2013 test method, the coercivity Hcj≥8500 Oe; (2) The maximum magnetic energy product (BH) according to GB / T 3217-2013 test. max ≥45kJ / m 3 (3) After high temperature environment test (150℃, 100h), the magnetic moment decay ≤3%; (4) According to GB / T3682-2000 test method, under test conditions of 310℃ and 10kg, the melt flow index MFR ≥100g / 10min; (5) According to GB / T1040.2-2006, the tensile strength ≥40MPa; (6) GB / T 9341-2008, the bending strength ≥50 MPa; (7) GB / T 1843-2008, the impact strength ≥5.0 MPa; (8) No cracking in high and low temperature impact test.
[0068] In some embodiments, the magnetic alloy powder is a rare earth magnetic alloy powder selected from at least one of neodymium iron boron, samarium iron nitrogen, and samarium cobalt. That is, one of them can be selected, or multiple composite magnetic alloy powders of neodymium iron boron, samarium iron nitrogen, and samarium cobalt can be selected.
[0069] In some embodiments, the rotor further includes a polymeric elastomer, which may be selected from at least one of glycidyl methacrylate-grafted ethylene propylene diene monomer (EPDM) rubber and glycidyl methacrylate-grafted hydrogenated styrene-butadiene block copolymer.
[0070] It should be noted that the magnetic material in this application can be in powder, granule, or block form, i.e., a magnet; the magnet can be in various shapes, not limited to tile, disc, cube, cylinder, ring, etc.
[0071] The rotor in this application can be manufactured using magnetic materials through processes such as compression molding, injection molding, extrusion molding, and calendering. The magnetic materials in this application, such as magnets, can be used in rotors involved in thermal management systems, such as magnetic rotors in control components (electronic expansion valves, water valves, etc.), heat exchange components (cooling plates, coolers, oil coolers, etc.), and drive components (electronic water pumps and oil pumps, etc.), and can meet the performance requirements of magnets in thermal management systems, such as the magnetic properties, thermal stability, processing performance, and mechanical properties of magnets.
[0072] This application also provides a thermal management system, which includes at least one of a pump, a valve, and a cooling device. The pump, valve, and cooling device may be made of magnetic material 4, or a magnetic composite material comprising magnetic material 4 (composed of magnetic alloy powder 1, a first coating layer 2, and a second coating layer 3), a resin binder 5, and a polymer elastomer 6.
[0073] The composite coating layers (first coating layer 2, second coating layer 3) include compounds containing -P(O)- structural segments and compounds containing... Compounds containing structural fragments.
[0074] In this application, the thermal management components in the thermal management system include at least one of a pump, a valve, and a cooling device. At least one of the pump, valve, and cooling device includes a magnetic material. The magnetic material includes magnetic alloy powder 1 with at least a portion of its surface covered by a first coating layer 2 and a second coating layer 3.
[0075] In some embodiments, the pump includes, but is not limited to, water pumps, oil pumps, etc., the valve includes, but is not limited to, refrigerant valves, water valves, etc., and the cooling device includes, but is not limited to, cooling plate, cooler, oil cooler, etc.
[0076] In addition, it should be noted that the thermal management system in this application mainly includes four parts: battery thermal management system, automotive air conditioning system, motor electronic control cooling system, and reducer cooling system; furthermore, the thermal management system in this application is a new energy vehicle thermal management system. The new energy vehicle thermal management system is mainly classified by cooling medium into liquid cooling circuit (cooling system for battery and motor, etc.), oil cooling circuit (cooling system for reducer, etc.), and refrigerant circuit (air conditioning system). The components involved include control components (electronic expansion valve, water valve, etc.), heat exchange components (cooling plate, cooler, oil cooler, etc.), and drive components (electronic water pump and oil pump, etc.). The magnets in the key components such as electronic expansion valve, water valve, electronic water pump, oil pump, cooling plate, cooler, and oil cooler are made of magnetic materials, and these magnets can meet the usage requirements of the new energy vehicle thermal management system.
[0077] The present application will be further described below through embodiments.
[0078] Example 1
[0079] A method for preparing a magnetic material includes the following steps:
[0080] (a) A magnetic material coated with a phosphate-polycatechol ethylamine composite coating is prepared by the following steps:
[0081] Step (I) involves dissolving phosphoric acid in ethanol solvent, with a phosphoric acid mass percentage of 1%; and adding magnetic alloy powder (neodymium iron boron alloy powder, coercivity Hcj: 9650 Oe, maximum energy product (BH)max: 122 kJ / m). 3 The magnetic alloy powder and the phosphate ethanol mixture were immersed in the solution at a mass ratio of 5:2. The mixture was stirred until it was fully in contact with the solution. After soaking at room temperature for 5 hours, the mixture was dried under vacuum to obtain magnetic powder coated with the first coating layer (porous phosphate).
[0082] In step (II), catechol ethylamine is dissolved in purified water to obtain a precursor solution with a mass percentage of 4% catechol ethylamine. The magnetic alloy powder material with the first coating layer treated in step (i) is immersed in the solution with a mass ratio of magnetic alloy powder to catechol ethylamine solution of 5:2. The temperature is maintained at 40-60°C during stirring for 5 hours, and triethanolamine is added dropwise to adjust the pH value to around 8.9. After filtration, the residual precursor aqueous solution is removed by rinsing with organic solvents such as ethanol, and then vacuum dried to obtain a magnetic alloy powder material with a second coating layer (polycatechol ethylamine).
[0083] (b) The magnetic composite material is obtained through the following steps:
[0084] Step (III): 90 parts of the magnetic material with composite coating obtained in step (a), 9 parts of polyphenylene sulfide resin binder, and 1 part of polymer elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate) are put into a high-speed mixer and mixed evenly to obtain a mixture.
[0085] Step (IV) involves adding the mixture to a twin-screw extruder, mixing and granulating it at 320°C to obtain granular magnetic composite material.
[0086] Example 2
[0087] A method for preparing a magnetic material, compared with Example 1, differs in that: in step (I), the mass percentage of phosphoric acid is 2%, and the mass ratio of magnetic alloy powder to phosphate ethanol mixed solution is 5:1.2; in step (II), the mass percentage of catechol ethylamine is 8%, and the mass ratio of magnetic alloy powder to catechol ethylamine solution is 5:1; the remaining steps are the same.
[0088] Example 3
[0089] A method for preparing a magnetic material, which differs from Example 1 in that: in step (II), triethanolamine is added dropwise to adjust its pH value to around 7.8; the remaining steps are the same.
[0090] Example 4
[0091] A method for preparing a magnetic material, compared with Example 1, differs in that: the mixing ratio in step (III) is 90 parts of the magnetic alloy powder with a composite coating obtained in step (a), 8.5 parts of polyphenylene sulfide resin binder, and 1.5 parts of polymer elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate); the remaining steps are the same.
[0092] Comparative Example 1
[0093] A method for preparing a magnetic material, compared with Example 1, differs in that the process of preparing a composite coating layer on the surface of magnetic alloy powder in step (a) is omitted, while the remaining steps are exactly the same as in Example 1; that is, steps (I) and (II) are omitted, and steps (III) and (IV) are performed directly to prepare granular magnetic composite materials.
[0094] Comparative Example 2
[0095] A method for preparing a magnetic material, compared with Example 1, differs in that, in step (a), a first phosphate coating layer is prepared on the surface of the magnetic alloy powder but a second coating layer is not prepared; the remaining steps are exactly the same as in Example 1. That is, after preparing the first coating layer on the surface of the magnetic alloy powder in step (I), step (II) in step (a) is omitted, and steps (III) and (IV) are directly performed to prepare granular magnetic composite materials.
[0096] Comparative Example 3
[0097] A method for preparing a magnetic material, compared with Example 1, differs in that, in step (a), a second polycatechol ethylamine coating is directly applied to the surface of the magnetic alloy powder without preparing a first phosphate coating layer, while the remaining steps are exactly the same as in Example 1; that is, step (I) in step (a) is omitted, and step (II) in step (a), as well as steps (III) and (IV) in step (b), are directly performed to prepare a particulate magnetic composite material.
[0098] Comparative Example 4
[0099] A method for preparing a magnetic material, which differs from Example 1 in that: the mixing ratio in step (III) is 90 parts of the magnetic alloy powder with a composite coating obtained in step (a), 10 parts of polyphenylene sulfide resin binder, and 0 parts (i.e., no addition) of polymer elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate); the remaining steps are the same.
[0100] Experimental Example 1
[0101] The specific surface area of the powdered magnetic materials obtained in steps (I) and (II) of step (a) in Examples 1-4 and Comparative Examples 1-3 was determined by static volumetric method, with units of m². 2 / g.
[0102] The coercivity performance (Hcj) of the powdered magnetic materials obtained in step (a) of Examples 1-4 and the granular magnetic composite materials obtained in step (b) of Comparative Examples 1-3 was tested according to GB / T 3217-2013, with the unit being Oe. The coercivity values of the powdered magnetic materials and granular magnetic composite materials were measured after being placed under high-temperature conditions for a certain period (300℃, 24 hours), and the difference was used to determine the degree of resistance to coercivity attenuation. The coating process for the magnetic alloy powder material in Comparative Example 4 was the same as in Example 1; therefore, relevant data for Comparative Example 4 are not listed in Table 1.
[0103] Table 1 Results of specific surface area and coercivity tests
[0104]
[0105]
[0106] As shown in Table 1, a comparison between Examples 1-4 and Comparative Examples 1-3 reveals that the coercivity of the powdered magnetic material obtained in step (I) and the granular magnetic composite material obtained in step (II) of Examples 1-3 is significantly better than that of Comparative Examples 1-3 in the environmental aging test (300℃, 24 hours). This indicates that the magnetic alloy powder material containing the composite coating in this application can maintain better magnetic properties after experiencing harsh environments. Furthermore, a comparison between Comparative Example 1 and Example 1 shows that the magnetic alloy powder without the composite coating performs the worst as a raw material, with a significant decrease in coercivity after the aging test. A comparison between Comparative Examples 2 and 3 and Example 1 shows that while magnetic alloy powder with only the first coating layer (i.e., phosphate coating layer) or the second coating layer (i.e., polycatechol ethylamine coating layer) has some effect, it is significantly less effective than that with the composite coating layer. To analyze the reasons, by comparing the specific surface area of the powder obtained in steps (I) and (II) of step (a), and comparing it with the specific surface area of the magnetic alloy powder raw material, it can be seen that: on the one hand, the specific surface area of the powder obtained in step (I) is significantly higher than that of the original magnetic alloy powder, indicating that the first coating layer contains a porous structure, thereby increasing the specific surface area of the powder material. In this process, the first coating layer containing the -P(O)- structural fragment compound is firmly connected to the magnetic alloy powder by chemical bonds; on the other hand, the specific surface area of the powder obtained in step (II) recovers to be very close to that of the original magnetic alloy powder, indicating that in this process, the first coating layer containing the -P(O)- structural fragment compound is firmly connected to the magnetic alloy powder by chemical bonds. The compounds of the structural fragments are firmly inserted, polymerized, and fixed inside and outside the pores of the first coating layer on the surface of the magnetic alloy powder, and the pores are sealed. The two work together to form a strong and dense composite coating layer, which effectively isolates the corrosion of water, oxygen and other substances in the environment and improves the stability of the coercivity performance of the magnetic material.
[0107] Experimental Example 2
[0108] The granular magnetic composite materials obtained in steps (b) of Examples 1-4 and Comparative Examples 1-3 were characterized by testing. The corresponding testing methods and sample preparation conditions are shown in Table 2. Maximum Magnetic Energy Product (BH) maxThe test methods for melt flow index (MFR), tensile strength, flexural strength, and impact strength are respectively referred to in the corresponding national standards in Table 2. Magnetic moment decay was measured by examining the magnetic moment value of a φ10×10mm cylinder (same as the maximum magnetic energy product test sample column) after magnetization saturation and the magnetic moment decay value after being placed at 150℃ for 100 hours. The high and low temperature impact cracking rate test involved rapidly switching between -40℃ and 150℃ for temperature impact on 10 circular rotors with metal shafts, each with an outer diameter of 12mm and an inner diameter of 4mm. Each temperature was maintained for 2 hours to fully reach the corresponding temperature, and then quickly transferred to another temperature and maintained for 2 hours. This cycle was repeated 500 times, and the number of cracks in the 10 samples was observed. The test results are shown in Table 3.
[0109] Table 2 Test methods and sample preparation conditions
[0110]
[0111] Table 3 Test Results
[0112]
[0113] As shown in Table 3, comparing Comparative Examples 1-4 with Examples 1-4, the magnetic material of the present invention exhibits a higher maximum magnetic energy product, lower magnetic moment decay, and superior mechanical properties. Furthermore, no cracking was observed during high and low temperature shock cycle testing after fabrication into rotor magnetic devices, meeting the requirements for injection-molded magnets used in the thermal management system of new energy vehicles. Specifically, comparing Comparative Example 1 with Examples 1-4 shows that magnetic materials without a composite coating layer on the surface of the magnetic alloy powder are easily damaged during processing, therefore (BH). max The magnetic materials exhibited low magnetic flux density (MFR) and mechanical strength, and significant magnetic moment decay after high-temperature accelerated environmental testing. Even with the addition of a polymeric elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate) to the resin adhesive layer, cracking still occurred after high and low temperature impact cycling tests. A comparison of Comparative Example 2 with Examples 1-4 shows that the magnetic material with a single first coating layer (phosphate coating layer) on the surface of the magnetic alloy powder has some improvement effect, but it is not as good as this application. This is because the phosphate coating layer has a porous structure that is not dense enough, and its compatibility with the organic resin adhesive layer is poor. Therefore (BH) maxThe MFR and mechanical strength are still lower than those of the examples, and the magnetic moment decay after high-temperature accelerated environmental testing is also higher than that of the examples. Even with the addition of a polymeric elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate) to the resin adhesive layer, cracking still occurs after high and low temperature impact cycling tests. A comparison between Comparative Example 3 and Examples 1-4 shows that the magnetic material with a single second coating layer (polycatechol ethylamine coating layer) on the surface of the magnetic alloy powder has a certain improvement effect, but it is not as good as that of this application. Although the polycatechol ethylamine coating layer has good compatibility with the organic resin adhesive layer, it is easy to peel off from the surface of the magnetic alloy powder during processing and shearing because it lacks the first coating layer with a porous structure as a point of force for polymerization and interpenetration. This leads to (BH). max The MFR and mechanical strength are still lower than those of the examples, and the magnetic moment decay after high-temperature accelerated environmental testing is also higher than that of the examples. Even with the addition of a polymeric elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate) to the resin adhesive layer, cracking still occurs after high and low temperature impact cycling tests. A comparison between Comparative Example 4 and Examples 1-4 shows that, because the magnetic alloy powder surface is coated with the same composite coating layer as in the examples, (BH) max The performance in terms of MFR and magnetic moment decay after high temperature accelerated environmental testing is comparable to that of the example. However, since there is no polymer elastomer (ethylene propylene diene monomer rubber grafted with glycidyl methacrylate) in the resin adhesive layer to play a toughening role, there is a cracking rate after high and low temperature impact cycling test.
[0114] like Figure 1 As shown, the powdered magnetic material prepared in this application has a magnetic alloy powder / magnetic alloy particle-composite coating structure. The composite coating includes a first coating layer (containing -P(O)- structural segment coating layer) and a second coating layer (containing... The first coating layer has a porous structure and is chemically bonded to the magnetic alloy powder, providing strong bonding strength. The second coating layer is at least partially intercalated and polymerized within the porous structure of the first coating layer, firmly bonded to it, and seals the porous structure of the first coating layer, making it dense. This effectively solves the problem of magnetic property and processing performance degradation during the processing and use of magnetic materials. Furthermore, as... Figure 2 As shown, the particulate magnetic composite material prepared in this application will... Figure 1 When powdered magnetic materials are compounded with resin binders and polymer elastomers, the resulting material possesses excellent magnetic properties, flow characteristics (MFR), mechanical strength, and resistance to magnetic moment decay and high / low temperature shock. Magnetic alloy powders have excellent applications in magnets used in control components (electronic expansion valves, water valves, etc.), heat exchange components (cooling plates, coolers, oil coolers, etc.), and drive components (electronic water pumps and oil pumps, etc.) of thermal management systems in new energy vehicles.
[0115] The above embodiments are only used to illustrate this application and are not intended to limit the technical solutions described in this application. The understanding of this application should be based on those skilled in the art. Although this specification has described this application in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to this application. All technical solutions and improvements that do not depart from the spirit and scope of this application should be covered within the scope of the claims of this application.
Claims
1. A magnetic material, characterized in that, The magnetic material is a magnetic alloy powder with at least a portion of its surface coated with a composite coating layer; wherein... The composite coating layer includes a first coating layer containing -P(O)- structural segments and a coating layer containing... The second coating layer of the structural fragment, -P(O)- structural fragment is chemically bonded to the metal atoms on the surface of the magnetic alloy powder; the first coating layer is a porous structure; the second coating layer covers the outside of the first coating layer and is at least partially intercalated and polymerized within the porous structure of the first coating layer; the material of the first coating layer is phosphate, and the material of the second coating layer is polycatechol ethylamine; The magnetic material was prepared using the following method: The compound containing the -P(O)- structural fragment is dissolved in an organic solvent, the magnetic alloy powder is immersed in it, stirred evenly to ensure full contact with the solution, soaked at room temperature for 1~24h, and then dried under vacuum or non-reactive protective atmosphere to obtain magnetic alloy powder coated with the first coating layer. Will contain The small molecule compound of the group is dissolved in water to obtain a precursor solution; magnetic alloy powder coated with the first coating layer is immersed in the solution and stirred at 40~60°C for 0.5~12 hours, and triethanolamine or ammonia is added dropwise to maintain the pH value at 7.2~10.5; after the reaction is completed, the mixture is filtered and washed to remove water, and dried under vacuum or non-reactive protective atmosphere to obtain the magnetic material.
2. The magnetic material according to claim 1, characterized in that, The magnetic material is in powder form; the magnetic alloy powder is selected from at least one of neodymium iron boron alloy powder, samarium iron nitrogen alloy powder, and samarium cobalt alloy powder.
3. A magnetic composite material comprising the magnetic material according to any one of claims 1-2 and an adhesive layer, wherein the adhesive layer is disposed on at least a portion of the surface of the magnetic material; the adhesive layer comprises a resin polymer and a polymeric elastomer dispersed in the resin polymer.
4. The magnetic composite material according to claim 3, characterized in that, The magnetic composite material is in granular form; the magnetic material content in the magnetic composite material is 83~93 wt.%, and the adhesive layer content is 7~17 wt.%.
5. The magnetic composite material according to claim 4, characterized in that, In the adhesive layer, the resin polymer is polyphenylene sulfide or polyamide, and the polymeric elastomer is selected from at least one of glycidyl methacrylate-grafted EPDM rubber and glycidyl methacrylate-grafted hydrogenated styrene-butadiene block copolymer.
6. A method for preparing the magnetic composite material as described in any one of claims 3-5, characterized in that, The preparation method includes the following steps: Magnetic materials, resin polymers, and high molecular weight elastomers are mixed evenly to form a mixture; the mixture is then added to a screw extruder for kneading and granulation to obtain the magnetic composite material.
7. A rotor, characterized in that, The rotor comprises the magnetic material according to any one of claims 1-2 or the magnetic composite material according to any one of claims 3-5.
8. A thermal management system comprising at least one of a pump, a valve, and a cooling device, characterized in that, At least one of the pump, the valve, and the cooling device comprises the magnetic material according to any one of claims 1-2 or the magnetic composite material according to any one of claims 3-5.