Preparation method of notebook computer non-contact external wireless charging receiver with built-in magnetic ring

Abstract

The application discloses a preparation method of a notebook computer non-contact external wireless charging receiver built-in magnetic ring, and comprises the following steps: mixing FeSiAl magnetic powder with three particle sizes after insulating coating according to a certain proportion, and then compressing and forming into a circular edge rectangle; and performing heat treatment to obtain a magnetic ring magnetic powder core, which can be used as the notebook computer non-contact external wireless charging receiver built-in magnetic ring, and has the advantages of high charging efficiency, fast charging speed, small size and light weight. The magnetic ring preparation method can effectively improve the coating layer structure of the magnetic ring magnetic powder core and the internal organization structure of the magnetic powder core, reduce the loss, improve the magnetic permeability, heat conductivity and direct current bias performance, and reduce the specific gravity of the magnetic powder core.

Description

Technical Field

[0001] This invention relates to a method for preparing a built-in magnetic ring for a laptop contactless external wireless charging receiver. Background Technology

[0002] Currently, laptops and desktops charge their built-in batteries via wired charging. Wireless charging, on the other hand, eliminates the need for a traditional charging cable. Instead, it uses wireless charging technology to transfer electrical energy through the interaction between the internal magnetic fields of a charging transmitter connected to a 220V circuit and a charging receiver connected to the device, thus charging the device's built-in rechargeable battery.

[0003] Currently, most wireless charging devices on the market are used in products such as mobile phones. Due to internal space limitations, laptops are not designed with built-in wireless charging receivers and therefore cannot be wirelessly charged.

[0004] If laptops were to adopt a wireless charging mode similar to that of mobile phones, a wireless charging receiver would need to be designed internally, increasing internal space, altering the internal structure, and requiring a new design. This is impractical, especially for existing laptops. Therefore, the goal is to achieve efficient wireless charging for laptops without changing their existing structure or incorporating a built-in wireless charging receiver. Using an external USB flash drive-style wireless charging receiver connected directly to the DC or USB interface, considering its hard-wired connection method, requires a small size, light weight, low heat generation, and good thermal conductivity. Therefore, its internal magnetic ring must be small, have strong charging capacity, high charging efficiency, low loss, and good thermal conductivity. Currently, conventional magnetic rings cannot meet these requirements. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, this invention provides a method for preparing a built-in magnetic ring for a contactless external wireless charging receiver for laptops. The magnetic ring provided by this invention can be used in USB flash drive-type external wireless charging receivers for laptops, enabling existing laptops to transfer power to a charging dock via a USB flash drive-type wireless charging receiver connected to a DC or USB interface without altering the laptop's structure, thus achieving high-efficiency wireless charging. It has the advantages of high charging efficiency, fast charging speed, safety and stability, and wide applicability.

[0006] The main ingredients of the magnetic ring core built into the notebook non-contact external wireless charging receiver of this invention are as follows by mass percentage: 2%–3% kaolin powder, 0.5%–1% sodium silicate, 1.5%–2.0% oxides, 2–2.5% fine synthetic diamond powder, 0.05%–0.1% Al powder, and the balance being FeSiAl magnetic powder and other elements and impurities. In addition to the main ingredients, it also includes lubricants, phosphoric acid, and other additives.

[0007] The FeSiAl magnetic powder is composed of the following composition by mass percentage: Si 9.0–9.6%, Al 5.2–5.6%, with the balance being Fe. The FeSiAl magnetic powder is composed of coarse powder, medium-coarse powder, and fine powder, mixed at mass percentages of 10%–15%, 65%–75%, and 15%–20% to obtain the FeSiAl magnetic powder required for magnetic ring preparation.

[0008] The coarse powder has a particle size of 120–150 μm, the medium-coarse powder has a particle size of 50–80 μm, and the fine powder has a particle size of 20–30 μm.

[0009] The particle size of the kaolin powder is 1–2 μm.

[0010] The oxide is one of zirconium oxide and aluminum oxide. The oxide has a purity of 99.99% and a particle size of 50–70 μm.

[0011] The particle size of the synthetic diamond powder is 10–20 μm.

[0012] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0013] The lubricant is one or a mixture of several of zinc stearate, barium stearate, and calcium stearate.

[0014] The present invention discloses a method for preparing a built-in magnetic ring for a laptop contactless external wireless charging receiver, comprising the following steps:

[0015] Step 1: FeSiAl magnetic powder phosphate passivation

[0016] Phosphoric acid was dissolved in anhydrous ethanol at a ratio of 1:10 (mass ratio) to form a phosphoric acid dilution solution. The phosphoric acid dilution solution was added to coarse FeSiAl magnetic powder, medium-coarse FeSiAl magnetic powder, and fine FeSiAl magnetic powder at a ratio of 3:10 (mass ratio) for surface passivation treatment. The passivation temperature was 50℃~70℃ and the passivation time was 10~30 minutes. After passivation, the powder was dried to obtain coarse passivated magnetic powder, medium-coarse passivated magnetic powder, and fine passivated magnetic powder, respectively.

[0017] Step 2: FeSiAl magnetic powder insulation coating

[0018] The oxide powder and synthetic diamond fine powder are mixed with the passivation magnetic powder coarse powder, passivation magnetic powder medium coarse powder, and passivation magnetic powder fine powder obtained in step 1 according to the specified proportions. After stirring evenly, kaolin and sodium silicate solutions dissolved in organic solvents are added, and the mixture is stirred evenly at a temperature of 70–160°C until dry, to obtain insulating coated magnetic powder coarse powder, insulating coated magnetic powder medium coarse powder, and insulating coated magnetic powder fine powder. When processing the coarse, medium, and fine powders separately, the oxide powder and synthetic diamond fine powder are divided into three portions according to the mass ratio of the coarse, medium, and fine powders for processing.

[0019] The proportions are as follows: 2%–3% kaolin powder, 0.5%–1% sodium silicate, 1.5%–2.0% oxides, 2–2.5% fine synthetic diamond powder, 0.05–0.1% Al powder, and the balance being FeSiAl passivated magnetic powder and other elements and impurities.

[0020] Step 3: FeSiAl magnetic powder mixing

[0021] Weigh, mix, and stir the coarse magnetic powder, medium coarse magnetic powder, and fine magnetic powder after the insulation coating in step 2 according to the proportions of 10% to 15%, 65% to 75%, and 15% to 20%, respectively, until they are evenly dispersed.

[0022] Step 4: Add lubricant and mix thoroughly. The amount of lubricant added should be 0.75–0.9% of the total mass of the FeSiAl magnetic powder obtained in Step 3.

[0023] Step 5: Pressing and molding

[0024] The mixed powder is pressed into a magnetic powder core using a molding die under a press. The pressing pressure is 23 t / cm². 2 -24 t / cm 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle (or oblong, capsule-shaped), as shown in the figure. Figure 1 (The long and short sides are A and D respectively), where A and D are 2-4cm and 1-2cm respectively.

[0025] Step 6: Heat treatment

[0026] Under protective gas, the magnetic powder core is first placed in a protective atmosphere furnace at 880-920℃ for heat treatment, with a holding time of 2-3 hours and a heating rate of 5-8℃ / min; then the temperature is lowered to 520±5℃, held for 1-2 hours, and then air-cooled.

[0027] The design basis of the method of this invention is:

[0028] Phosphoric acid passivation and insulating coating: Phosphoric acid passivation of FeSiAl magnetic powder can form an oxide film by reacting phosphoric acid with the surface of the magnetic powder. This film has the functions of insulation, reducing eddy current loss, and corrosion protection. The oxide, synthetic diamond-kaolin composite insulating coating process can form a second dense and uniform insulating coating layer on the surface of the iron-silicon-aluminum magnetic powder particles (e.g., ...). Figure 2 As shown in the figure, its coating rate is 100% and its porosity is 0.01%. Its main function is insulation and reducing eddy current loss. During the powder core pressing process, due to the oxides and artificial diamonds in the composite insulating coating layer hindering the flow of powder, the air gap in the powder core increases, the anti-demagnetization ability is improved, and the DC bias performance of the powder core can be improved.

[0029] Synthetic diamond: Synthetic diamond is produced by epitaxial growth of diamond on diamond seed crystals or certain substrates using static ultra-high pressure (50–100 kb, i.e., 5–10 GPa) and high temperature (1100–3000 °C) technology. This is achieved through the reaction of carbonaceous raw materials such as graphite with certain metals (alloys), or by utilizing carbon sources precipitated during the pyrolysis and electrolysis of certain carbon-containing substances. Typical crystal forms include cubic (hexahedral), octahedral, and hexahedral, as well as their transitional forms. It is characterized by its low specific gravity, low cost, and good compressive strength, impact strength, wear resistance, and heat resistance. Synthetic diamond is non-conductive but has excellent thermal conductivity, reaching up to 2000 W / mK. Adding an appropriate amount of synthetic diamond powder to the FeSiAl magnetic powder insulating coating layer, and designing the ratio of kaolin powder, synthetic diamond powder, and oxide powder, a composite coating layer with a specific structure is formed. When the ratio of the three is 1:0.8:0.67 to 1:1:0.75, and the total amount is 5.5% to 7.5% of the magnetic powder core material mass, the oxide and synthetic diamond are dispersed, interwoven, and vein-like distributed in the kaolin. Figure 2 , 3 As shown in the figure. The resulting insulating coating layer is complete, has high insulation, low eddy current loss of the magnetic powder core, good DC bias performance, improved thermal conductivity and heat dissipation, and reduced overall weight of the magnetic powder core. Figure 4 , 5 The microstructure of composite coatings with proportions outside this range (1:0.8:0.67 to 1:1:0.75). When the ratio of synthetic diamond powder to oxide powder is lower than this range, the coating is incomplete and the coating rate is low, all below 95% (e.g., Figure 4 When the proportion is higher than this value, the distribution of its oxides and synthetic diamonds in kaolin is not ideal, but rather uneven and isolated (e.g., Figure 5 ).

[0030] Oxides: Oxides such as zirconium oxide and aluminum oxide have the characteristics of good insulation, good stability and low price. In insulating coatings, they can improve insulation performance, reduce eddy current loss and improve DC bias performance. However, their thermal conductivity is insufficient. When combined with artificial diamond and kaolin in an appropriate proportion, an insulating coating with low eddy current loss, good DC bias performance, good thermal conductivity (thermal conductivity can reach 130W / mK) and low cost can be obtained.

[0031] Al: Al is a low-density, low-cost metallic element that can react with synthetic diamond under certain thermodynamic conditions to form compounds. Adding a small amount of Al powder to the insulating coating layer and holding it at 880–920℃ for 2–3 hours during a predetermined heat treatment process allows Al to react slightly with the synthetic diamond, forming a 5–7 μm Al₄C₃ barrier layer on the diamond surface. This increases the interfacial resistance, further enhancing the insulation of the insulating coating layer. This results in a high resistivity for the magnetic powder core, reducing eddy current losses, improving charging capacity, and facilitating heat dissipation.

[0032] The magnetic powder core is designed and pressed into a rounded rectangle, which can meet the shape requirements of USB flash drive-type external chargers. On the other hand, its powder core has high density, reasonable magnetic field line distribution, high magnetic flux density, and large magnetic flux, which is conducive to fast charging.

[0033] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0034] 1. Through reasonable design, kaolin powder, oxide powder, and artificial diamond powder form an insulating coating layer with a specific structure and composition around FeSiAl magnetic powder. The oxide and artificial diamond are distributed in a dispersed, interwoven, and vein-like manner in the kaolin. The surface of the artificial diamond is wrapped with an Al4C3 barrier layer, which is formed by the reaction of a small amount of Al powder with the artificial diamond during the set heat treatment process. The insulation of the coating layer with this structure is significantly improved, reducing the eddy current loss of the magnetic powder core, improving the DC bias performance, reducing the heat generation of the magnetic powder core and even the charger, improving performance, and extending the service time and life.

[0035] 2. In the above-mentioned composite coating containing synthetic diamond powder, the proportion of synthetic diamond powder is approximately 15-30%, and the pressure is 23 t / cm. 2 -24 t / cm 2 Under pressure, the powder is distributed in a vein-like pattern in the coating layer, which significantly improves the thermal conductivity of the coating layer compared to composite coating layers without artificial diamond powder. The thermal conductivity of the magnetic powder core can reach 130W / mK, while that of the magnetic powder core without diamond powder is only 85W / mK. This can improve the heat dissipation capacity and service life of the magnetic powder core and the charger.

[0036] 3. In the above-mentioned magnetic powder core containing synthetic diamond powder, the proportion of synthetic diamond powder is about 1.5% to 3.0%. Due to the low density of synthetic diamond, the overall weight of the magnetic powder core can be reduced.

[0037] 4. The magnetic powder core of this invention, made from FeSiAl magnetic powder with a specific composition and structural insulating coating, features a rounded-edge rectangular structure. This meets the shape requirements of USB flash drive-type external chargers, and its magnetic field lines are rationally distributed. The magnetic powder core has high magnetic flux density and large magnetic flux, which is beneficial for fast charging. The magnetic flux density of the magnetic powder core can reach 1.15–1.20 Wb / m². 2 It improves upon the performance of magnetic powder cores with ordinary structures by 10% to 15%.

[0038] The present invention discloses a method for preparing a built-in magnetic ring for a laptop's contactless external wireless charging receiver. The resulting magnetic ring exhibits advantages such as low eddy current loss during charging, good DC bias performance, high magnetic flux density, and good thermal conductivity. Testing with a magnetoelectric testing system revealed that the magnetic permeability of the magnetic powder core is 131–143 H / m, with a maximum of 143 H / m; the loss is 122.1–127.4 mW / cm². 3 The lowest value can be as low as 122.1 mW / cm 3 DC bias performance (100kHz, H=100Oe) is 62.1%–64.6%, with a maximum of 64.6%; thermal conductivity can reach up to 130W / mK; magnetic flux density can reach 1.15–1.20Wb / m 2 It achieves a 10%–15% increase in specific gravity compared to conventional magnetic powder cores; the lowest specific gravity can be as low as 6.93 g / cm³. 3 Ordinary FeSiAl magnetic powder cores typically have a loss greater than 140mW / cm. 3 It has a DC bias performance of less than 62%, a thermal conductivity of approximately 85 W / mK, and a magnetic flux density of 1.0–1.05 Wb / m. 2 Specific gravity 7.05 g / cm³ 3 As can be seen, the key indicators mentioned above have been improved in this invention, enabling the charger to have the advantages of strong charging capacity, high charging efficiency, light weight, and long lifespan. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a magnetic ring.

[0040] Figure 2 This describes the morphology of the composite coating layer of the present invention.

[0041] Figure 3 This is the composite coating structure of the present invention.

[0042] Figure 4 It is a composite coating structure in which the proportion of artificial diamond powder and oxide powder is lower than that of the present invention.

[0043] Figure 5 It is a composite coating morphology in which the proportion of artificial diamond powder and oxide powder is higher than that of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Specific implementation examples are shown in Table 1.

[0045] Table 1 List of Examples

[0046]

[0047] Example 1:

[0048] 1. The composition of the magnetic powder core ingredients by mass percentage is as follows:

[0049] The composition consists of 93% FeSiAl magnetic powder, 2% kaolin powder, 0.5% sodium silicate, 1.5% oxides, 2% fine synthetic diamond powder, 0.05% Al powder, 0.75% lubricant, 0.1% phosphoric acid, and the balance being other elements and impurities.

[0050] The FeSiAl magnetic powder composition, by mass percentage, is: Si 9.0–9.6%, Al 5.2–5.6%, with the balance being Fe. Coarse powder, medium-coarse powder, and fine powder, with particle sizes of 120–150 μm, 50–80 μm, and 20–30 μm respectively, are mixed at proportions of 13%, 62%, and 18% to obtain the FeSiAl magnetic powder required for magnetic ring preparation.

[0051] The particle size of kaolin is 1–2 μm.

[0052] The oxide is one of zirconium oxide and aluminum oxide, with a purity of 99.99% and a particle size of 50–70 μm.

[0053] The particle size of synthetic diamond powder is 10–20 μm.

[0054] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0055] The lubricant is zinc stearate.

[0056] 2. The method for preparing a magnetic ring includes the following steps:

[0057] Step 1: Phosphate passivation of FeSiAl magnetic powder: Phosphoric acid is dissolved in anhydrous ethanol at a ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution is added to FeSiAl coarse powder, medium coarse powder and fine powder at a ratio of 3:10 respectively for surface passivation treatment. The passivation temperature is 60℃ and the passivation time is 30 minutes. After the passivation is completed, the powder is dried until it is dry.

[0058] Step 2, FeSiAl magnetic powder insulation coating: Mix the oxide powder, fine synthetic diamond powder, and the magnetic powder passivated by phosphoric acid in Step 1 in a certain proportion, with the total addition amount of the two powders being 3.5% of the total mass of the ingredients. After stirring evenly, add 2.4% of the total mass of kaolin dissolved in an organic solvent and 0.5% of the total mass of sodium silicate solution. Stir evenly at 150°C and continue stirring until dry.

[0059] Step 3, FeSiAl magnetic powder mixing: Weigh, mix and stir the FeSiAl coarse powder, medium coarse powder and fine powder after passivation in step 1 and insulation coating in step 2 in proportions of 13%, 62% and 18% respectively, until they are evenly dispersed.

[0060] Step 4: Add lubricant: Add lubricant and mix evenly;

[0061] Step 5: Pressing and Molding: The powder is pressed into shape using a molding die under a press to form a magnetic powder core. The pressing pressure is 23 t / cm². 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle. See the shape below. Figure 1 (The long and short sides are A and D respectively), where A and D are 3cm and 1.5cm respectively.

[0062] Step 6, Heat treatment: Under protective gas, the magnetic powder core is first placed in an 880℃ atmosphere protection furnace for heat treatment, and the holding time is 3 hours with a heating rate of 8℃ / min; then the temperature is lowered to 520±5℃, held for 2 hours, and then air-cooled.

[0063] Example 2:

[0064] 1. The composition of the magnetic powder core ingredients by mass percentage is as follows:

[0065] The composition consists of 92% FeSiAl magnetic powder, 2.4% kaolin powder, 0.5% sodium silicate, 1.8% oxides, 2.3% fine synthetic diamond powder, 0.05% Al powder, 0.75% lubricant, 0.1% phosphoric acid, and the balance being other elements and impurities.

[0066] The FeSiAl magnetic powder composition by mass percentage is: Si 9.0-9.6%, Al 5.2-5.6%, with the balance being Fe. The coarse powder, medium-coarse powder, and fine powder have particle sizes of 120-150μm, 50-80μm, and 20-30μm, respectively, and are mixed in proportions of 13%, 62%, and 17% to obtain the FeSiAl magnetic powder required for the preparation of magnetic rings.

[0067] The particle size of kaolin is 1–2 μm.

[0068] The oxide is one of zirconium oxide and aluminum oxide, with a purity of 99.99% and a particle size of 50–70 μm.

[0069] The particle size of synthetic diamond powder is 10–20 μm.

[0070] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0071] The lubricant is zinc stearate.

[0072] 2. The method for preparing a magnetic ring includes the following steps:

[0073] Step 1: Phosphate passivation of FeSiAl magnetic powder: Phosphoric acid is dissolved in anhydrous ethanol at a ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution is added to FeSiAl coarse powder, medium coarse powder, and fine powder at a ratio of 3:10 respectively for surface passivation treatment. The passivation temperature is 60℃ and the passivation time is 30 minutes. After passivation, the powder is dried until it is dry.

[0074] Step 2, FeSiAl magnetic powder insulation coating: Mix the oxide powder, fine synthetic diamond powder, and the magnetic powder passivated by phosphoric acid in Step 1 in a certain proportion. The total amount of the two powders added is 4.1% of the total mass of the ingredients. After stirring evenly, add 2.4% of the total mass of kaolin dissolved in an organic solvent and 0.5% of the total mass of sodium silicate solution. Stir evenly at 150°C and continue stirring until dry.

[0075] Step 3, FeSiAl magnetic powder mixing: Weigh, mix and stir the FeSiAl coarse powder, medium coarse powder and fine powder after passivation in step 1 and insulation coating in step 2 in proportions of 13%, 62% and 18% respectively, until they are evenly dispersed.

[0076] Step 4: Add lubricant: Add lubricant and mix evenly;

[0077] Step 5: Pressing and Molding: The powder is pressed into shape using a molding die under a press to form a magnetic powder core. The pressing pressure is 23 t / cm². 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle. See the shape below. Figure 1 (The long and short sides are A and D respectively), where A and D are 3cm and 1.5cm respectively.

[0078] Step 6, Heat treatment: Under protective gas, the magnetic powder core is first placed in an 880℃ atmosphere protection furnace for heat treatment, and the holding time is 3 hours with a heating rate of 8℃ / min; then the temperature is lowered to 520±5℃, held for 2 hours, and then air-cooled.

[0079] Example 3:

[0080] 1. The composition of the magnetic powder core ingredients by mass percentage is as follows:

[0081] The composition consists of 93% FeSiAl magnetic powder, 2% kaolin powder, 0.5% sodium silicate, 1.5% oxides, 2% fine synthetic diamond powder, 0.05% Al powder, 0.75% lubricant, 0.1% phosphoric acid, and the remainder being other elements and impurities.

[0082] The FeSiAl magnetic powder composition by mass percentage is: Si 9.0-9.6%, Al 5.2-5.6%, with the balance being Fe. The coarse powder, medium-coarse powder, and fine powder have particle sizes of 120-150μm, 50-80μm, and 20-30μm, respectively, and are mixed in proportions of 13%, 62%, and 18% to obtain the FeSiAl magnetic powder required for the preparation of magnetic rings.

[0083] The particle size of kaolin is 1–2 μm.

[0084] The oxide is one of zirconium oxide and aluminum oxide, with a purity of 99.99% and a particle size of 50–70 μm.

[0085] The particle size of synthetic diamond powder is 10–20 μm.

[0086] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0087] The lubricant is zinc stearate.

[0088] 2. The method for preparing a magnetic ring includes the following steps:

[0089] Step 1: Phosphate passivation of FeSiAl magnetic powder: Phosphoric acid is dissolved in anhydrous ethanol at a ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution is added to FeSiAl coarse powder, medium coarse powder, and fine powder at a ratio of 3:10 respectively for surface passivation treatment. The passivation temperature is 60℃ and the passivation time is 30 minutes. After passivation, the powder is dried until it is dry.

[0090] Step 2, FeSiAl magnetic powder insulation coating: Mix the oxide powder, fine synthetic diamond powder, and the magnetic powder passivated by phosphoric acid in Step 1 in a certain proportion, with the total addition amount of the two powders being 3.5% of the total mass of the ingredients. After stirring evenly, add 2.4% of the total mass of kaolin dissolved in an organic solvent and 0.5% of the total mass of sodium silicate solution. Stir evenly at 150°C and continue stirring until dry.

[0091] Step 3, FeSiAl magnetic powder mixing: Weigh, mix and stir the FeSiAl coarse powder, medium coarse powder and fine powder after passivation in step 1 and insulation coating in step 2 in proportions of 13%, 62% and 18% respectively, until they are evenly dispersed.

[0092] Step 4: Add lubricant: Add lubricant and mix evenly;

[0093] Step 5: Pressing and Molding: The powder is pressed into shape using a molding die under a press to form a magnetic powder core. The pressing pressure is 23 t / cm². 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle. See the shape below. Figure 1 (The long and short sides are A and D respectively), where A and D are 3cm and 1.5cm respectively.

[0094] Step 6, Heat treatment: Under protective gas, the magnetic powder core is first placed in an 880℃ atmosphere protection furnace for heat treatment, and the holding time is 3 hours with a heating rate of 8℃ / min; then the temperature is lowered to 520±5℃, held for 2 hours, and then air-cooled.

[0095] Example 4:

[0096] 1. The composition of the magnetic powder core ingredients by mass percentage is as follows:

[0097] The composition consists of 93% FeSiAl magnetic powder, 2% kaolin powder, 0.5% sodium silicate, 1.5% oxides, 2% fine synthetic diamond powder, 0.05% Al powder, 0.75% lubricant, 0.1% phosphoric acid, and the remainder being other elements and impurities.

[0098] The FeSiAl magnetic powder composition by mass percentage is: Si 9.0-9.6%, Al 5.2-5.6%, with the balance being Fe. The coarse powder, medium-coarse powder, and fine powder have particle sizes of 120-150μm, 50-80μm, and 20-30μm, respectively, and are mixed in proportions of 13%, 62%, and 18% to obtain the FeSiAl magnetic powder required for the preparation of magnetic rings.

[0099] The particle size of kaolin is 1–2 μm.

[0100] The oxide is one of zirconium oxide and aluminum oxide, with a purity of 99.99% and a particle size of 50–70 μm.

[0101] The particle size of synthetic diamond powder is 10–20 μm.

[0102] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0103] The lubricant is zinc stearate.

[0104] 2. The method for preparing a magnetic ring includes the following steps:

[0105] Step 1: Phosphate passivation of FeSiAl magnetic powder: Phosphoric acid is dissolved in anhydrous ethanol at a ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution is added to FeSiAl coarse powder, medium coarse powder, and fine powder at a ratio of 3:10 respectively for surface passivation treatment. The passivation temperature is 60℃ and the passivation time is 30 minutes. After passivation, the powder is dried until it is dry.

[0106] Step 2, FeSiAl magnetic powder insulation coating: Mix the oxide powder, fine synthetic diamond powder, and the magnetic powder passivated by phosphoric acid in Step 1 in a certain proportion, with the total addition amount of the two powders being 3.5% of the total mass of the ingredients. After stirring evenly, add 2.4% of the total mass of kaolin dissolved in an organic solvent and 0.5% of the total mass of sodium silicate solution. Stir evenly at 150°C and continue stirring until dry.

[0107] Step 3, FeSiAl magnetic powder mixing: Weigh, mix and stir the FeSiAl coarse powder, medium coarse powder and fine powder after passivation in step 1 and insulation coating in step 2 in proportions of 13%, 62% and 18% respectively, until they are evenly dispersed.

[0108] Step 4: Add lubricant: Add lubricant and mix evenly;

[0109] Step 5: Pressing and Molding: The powder is pressed into shape using a molding die under a press to form a magnetic powder core. The pressing pressure is 23 t / cm². 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle. See the shape below. Figure 1 (The long and short sides are A and D respectively), where A and D are 3cm and 1.5cm respectively.

[0110] Step 6, Heat treatment: Under protective gas, the magnetic powder core is first placed in an 880℃ atmosphere protection furnace for heat treatment, and the holding time is 3 hours with a heating rate of 8℃ / min; then the temperature is lowered to 520±5℃, held for 2 hours, and then air-cooled.

[0111] Example 5:

[0112] 1. The composition of the magnetic powder core ingredients by mass percentage is as follows:

[0113] The composition consists of 93% FeSiAl magnetic powder, 2% kaolin powder, 0.5% sodium silicate, 1.5% oxides, 2% fine synthetic diamond powder, 0.05% Al powder, 0.75% lubricant, 0.1% phosphoric acid, and the remainder being other elements and impurities.

[0114] The FeSiAl magnetic powder composition by mass percentage is: Si 9.0-9.6%, Al 5.2-5.6%, with the balance being Fe. The coarse powder, medium-coarse powder, and fine powder have particle sizes of 120-150μm, 50-80μm, and 20-30μm, respectively, and are mixed in proportions of 13%, 62%, and 18% to obtain the FeSiAl magnetic powder required for the preparation of magnetic rings.

[0115] The particle size of kaolin is 1–2 μm.

[0116] The oxide is one of zirconium oxide and aluminum oxide, with a purity of 99.99% and a particle size of 50–70 μm.

[0117] The particle size of synthetic diamond powder is 10–20 μm.

[0118] The Al powder has a purity of 99.99% and a particle size of 10–20 μm.

[0119] The lubricant is zinc stearate.

[0120] 2. The method for preparing a magnetic ring includes the following steps:

[0121] Step 1: Phosphate passivation of FeSiAl magnetic powder: Phosphoric acid is dissolved in anhydrous ethanol at a ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution is added to FeSiAl coarse powder, medium coarse powder, and fine powder at a ratio of 3:10 respectively for surface passivation treatment. The passivation temperature is 60℃ and the passivation time is 30 minutes. After passivation, the powder is dried until it is dry.

[0122] Step 2, FeSiAl magnetic powder insulation coating: Mix the oxide powder, fine synthetic diamond powder, and the magnetic powder passivated by phosphoric acid in Step 1 in a certain proportion, with the total addition amount of the two powders being 3.5% of the total mass of the ingredients. After stirring evenly, add 2.4% of the total mass of kaolin dissolved in an organic solvent and 0.5% of the total mass of sodium silicate solution. Stir evenly at 150°C and continue stirring until dry.

[0123] Step 3, FeSiAl magnetic powder mixing: Weigh, mix and stir the FeSiAl coarse powder, medium coarse powder and fine powder after passivation in step 1 and insulation coating in step 2 in proportions of 13%, 62% and 18% respectively, until they are evenly dispersed.

[0124] Step 4: Add lubricant: Add lubricant and mix evenly;

[0125] Step 5: Pressing and Molding: The powder is pressed into shape using a molding die under a press to form a magnetic powder core. The pressing pressure is 23 t / cm². 2 The horizontal cross-sectional shape of the molding die is a rounded rectangle. See the shape below. Figure 1(The long and short sides are A and D respectively), where A and D are 3cm and 1.5cm respectively.

[0126] Step 6, Heat treatment: Under protective gas, the magnetic powder core is first placed in an 880℃ atmosphere protection furnace for heat treatment, and the holding time is 3 hours with a heating rate of 8℃ / min; then the temperature is lowered to 520±5℃, held for 2 hours, and then air-cooled.

[0127] In Example 1, the FeSiAl magnetic powder contained 13% coarse powder, 62% medium-coarse powder, and 18% fine powder, while the proportions of kaolin powder, synthetic diamond powder, and oxide powder were 2%, 2%, and 1.5%, respectively. The powder core had a relatively large air gap, resulting in good DC bias performance, low loss, and good thermal conductivity. Testing showed its permeability to be 138 H / m, its DC bias performance (100 kHz, H = 100 Oe) to be 62.7%, and its loss to be 127.4 mW / cm². 3 Its thermal conductivity reaches 107 W / mK, and its magnetic flux density is 1.15 Wb / m. 2 Specific gravity 7.01 g / cm³ 3 .

[0128] In Example 2, the FeSiAl magnetic powder contained 13% coarse powder, 62% medium-coarse powder, and 17% fine powder, while the proportions of kaolin powder, synthetic diamond powder, and oxide powder were 2.4%, 2.3%, and 1.8%, respectively. The coating thickness was higher than in Example 1, and the proportion of synthetic diamond in the coating structure increased, resulting in improved distribution, better pulse connectivity, enhanced insulation, reduced losses, and improved thermal conductivity. Testing showed a permeability of 142 H / m, a DC bias performance (100 kHz, H = 100 Oe) of 64.1%, and a loss of 124.2 mW / cm². 3 It has a thermal conductivity of 126 W / mK and a magnetic flux density of 1.20 Wb / m 2 Specific gravity 6.97 g / cm³ 3 .

[0129] In Example 3, the proportions of coarse, medium-coarse, and fine powders in the FeSiAl magnetic powder were the same as in Example 2. The proportions of kaolin powder, synthetic diamond powder, and oxide powder were 2.4%, 2.5%, and 1.6%, respectively. The ratio of synthetic diamond to oxide in the coating layer structure was greater than in Example 2, resulting in improved distribution of synthetic diamond, better pulse connectivity, improved insulation of the coating layer, reduced losses, and improved thermal conductivity. The first-stage heat treatment temperature was higher than in Example 2, which further reduced the stress generated during the pressing process, increased the magnetic permeability, and promoted the reaction between Al and synthetic diamond. The Al4C3 film thickness was increased compared to Example 2, improving insulation and reducing eddy current losses. Testing showed a magnetic permeability of 143 H / m, a DC bias performance (100kHz, H=100Oe) of 64.4%, and a loss of 122.1 mW / cm². 3It has a thermal conductivity of 130 W / mK and a magnetic flux density of 1.20 Wb / m 2 Specific gravity 6.96 g / cm³ 3 It exhibits excellent overall performance.

[0130] In Example 4, the FeSiAl magnetic powder contained 12% coarse powder, 62% medium-coarse powder, and 17% fine powder, respectively, with a lower total proportion than in Example 3. The proportions of kaolin powder, synthetic diamond powder, and oxide powder were 2.4%, 2.5%, and 2.0%, respectively. The coating thickness was greater than in Examples 1, 2, and 3, resulting in improved insulation and reduced eddy current losses, but a decrease in permeability. Thermal conductivity also decreased compared to Example 3. Although eddy current losses decreased, hysteresis losses increased, and the total loss was still higher than in Example 3. Testing revealed a permeability of 136 H / m, a DC bias performance (100 kHz, H = 100 Oe) of 64.3%, and a loss of 124.4 mW / cm². 3 Thermal conductivity 118 W / mK, magnetic flux density 1.18 Wb / m 2 Specific gravity 6.96 g / cm³ 3 .

[0131] In Example 5, the FeSiAl magnetic powder contained 9% coarse powder, 67% medium-coarse powder, and 14% fine powder, with a total proportion lower than that in Example 4. However, the proportion of medium-coarse powder was increased, resulting in a lower core density and lower permeability compared to Example 4, while the DC bias performance was improved. The proportions of kaolin powder, synthetic diamond powder, and oxide powder were 3.0%, 2.0%, and 2.5%, respectively. The increased addition of sodium silicate resulted in a thicker coating layer than in Example 4. The increased proportions of kaolin and sodium silicate in the coating layer structure improved the coating layer strength, but reduced insulation and thermal conductivity, and increased losses. Testing revealed a permeability of 131 H / m, a DC bias performance (100 kHz, H = 100 Oe) of 64.6%, and a loss of 123.5 mW / cm². 3 Its thermal conductivity reaches 119 W / mK, and its magnetic flux density is 1.18 Wb / m. 2 Specific gravity 6.93 g / cm³ 3 .

[0132] In summary, the magnetic ring preparation method of this invention can effectively improve the structure of the magnetic powder core coating layer and the internal structure of the magnetic powder core, reduce losses, improve magnetic permeability, thermal conductivity, and DC bias performance, and reduce the specific gravity of the magnetic powder core. As a result, the non-contact external wireless charging receiver for laptops can achieve high charging efficiency, fast charging speed, small size, light weight, safety and stability, and wide applicability.

[0133] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a built-in magnetic ring for a laptop contactless external wireless charging receiver, characterized in that: The main ingredients of the built-in magnetic ring and magnetic powder core of the laptop non-contact external wireless charging receiver are as follows by mass percentage: 2%~3% kaolin powder, 0.5%~1% sodium silicate, 1.5%~2.0% oxide, 2~2.5% artificial diamond fine powder, 0.05~0.1% Al powder, 0.1% other elements and impurities, and the balance is FeSiAl magnetic powder; The FeSiAl magnetic powder is composed of the following components by mass percentage: Si 9.0~9.6%, Al 5.2~5.6%, with the balance being Fe; The FeSiAl magnetic powder is composed of coarse powder, medium coarse powder and fine powder. The coarse powder has a particle size of 120~150μm, the medium coarse powder has a particle size of 50~80μm, and the fine powder has a particle size of 20~30μm. The particle size of the kaolin powder is 1~2μm; The oxide is one of zirconium oxide and aluminum oxide, with a particle size of 50~70μm; The particle size of the synthetic diamond powder is 10~20μm; The particle size of the Al powder is 10~20μm; The method for preparing the built-in magnetic ring of the laptop contactless external wireless charging receiver includes the following steps: Step 1: FeSiAl magnetic powder phosphate passivation Phosphoric acid was dissolved in anhydrous ethanol at a mass ratio of 1:10 to form a phosphoric acid dilution solution. The phosphoric acid dilution solution was added to coarse FeSiAl magnetic powder, medium-coarse FeSiAl magnetic powder, and fine FeSiAl magnetic powder at a mass ratio of 3:10, respectively, for surface passivation treatment. The passivation temperature was 50℃~70℃, and the passivation time was 10~30 minutes. After passivation, the powder was dried to obtain coarse passivated magnetic powder, medium-coarse passivated magnetic powder, and fine passivated magnetic powder, respectively. Step 2: FeSiAl magnetic powder insulation coating The oxide powder, the fine powder of artificial diamond, and the coarse powder of passivated magnetic powder obtained in step 1 are mixed and stirred evenly. Then, kaolin and sodium silicate solution dissolved in organic solvent are added and stirred evenly at 70~160℃. The mixture is stirred continuously until dry to obtain coarse powder of insulating coated magnetic powder. The same treatment method is used to obtain coarse powder of insulating coated magnetic powder and fine powder of insulating coated magnetic powder respectively. Step 3: FeSiAl magnetic powder mixing Mix and stir the coarse magnetic powder, medium coarse magnetic powder and fine magnetic powder after the insulation coating in step 2, and disperse them evenly. Step 4: Add lubricant and mix thoroughly; Step 5: Pressing and molding The mixed powder is pressed into shape using a molding die under a press to form a magnetic powder core. Step 6: Heat treatment Under a protective gas atmosphere, the magnetic powder core is first placed in a protective furnace at 880~920℃ for heat treatment. The added Al powder reacts with the synthetic diamond during the heat treatment process to form an Al4C3 barrier layer on the surface. Then, the temperature is lowered to 520±5℃, held at that temperature, and then air-cooled.

2. The preparation method according to claim 1, characterized in that: In step 3, the coarse magnetic powder, medium coarse magnetic powder, and fine magnetic powder after insulation coating in step 2 are weighed, mixed, and stirred in proportions of 10%~15%, 65%~75%, and 15%~20% respectively, until they are evenly dispersed.

3. The preparation method according to claim 1, characterized in that: In step 5, the pressing pressure is 23 t / cm. 2 -24 t / cm 2 .

4. The preparation method according to claim 1, characterized in that: In step 5, the horizontal cross-sectional shape of the forming mold is a rounded rectangle.

5. The preparation method according to claim 1, characterized in that: In step 6, the heating rate to 880~920℃ is 5~8℃ / min, and the holding time is 2~3h; after cooling to 520±5℃, the temperature is held for 1~2h.

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