A magnetic conducting plate assembly, a sound production device and an electronic device

Abstract

This invention discloses a magnetically conductive plate assembly, a sound-generating device, and an electronic device, relating to the field of acoustic technology. The magnetically conductive plate assembly includes a body portion and a composite coating disposed on the surface of the body portion. The composite coating includes a first coating and a second coating. The first coating is disposed on the surface of the body portion and is composed of a polycrystalline material. The second coating is disposed on the surface of the first coating away from the body portion. The saturation magnetic induction intensity of the first coating is 1.5~3 T, and the charge transfer resistance of the second coating in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 The magnetic conductive plate assembly of the present invention aims to solve the technical problem of how to improve the magnetic permeability and corrosion resistance of the magnetic conductive plate assembly.

Description

Technical Field

[0001] This invention relates to the field of acoustics, and more particularly to a magnetic plate assembly, a sound-generating device, and an electronic device. Background Technology

[0002] In the manufacture of magnetic plates for loudspeakers, especially thin, high-sensitivity loudspeakers, the base material (such as low-carbon steel such as SPCC) is low in cost and easy to process, but its own saturation magnetic induction intensity is limited, and its surface is prone to oxidation and corrosion in high temperature, high humidity or salt spray environments.

[0003] Traditional techniques typically provide corrosion protection for magnetic plates through plating. However, these conventional plating materials are mostly non-ferromagnetic, which can form a "magnetoresistance layer" in the magnetic circuit, thus reducing the magnetic permeability of the magnetic components. On the other hand, if plating materials with high saturation magnetic induction intensity are used to improve magnetic permeability, their own corrosion resistance in harsh environments is often insufficient, and they are prone to oxidation. The generated oxides fill the spaces between the grain boundaries of the plating, causing the magnetic field lines to be blocked and the magnetic permeability to gradually deteriorate. Summary of the Invention

[0004] The main objective of this invention is to provide a magnetic plate assembly, a sound-generating device, and an electronic device, aiming to solve the technical problem of how to improve the magnetic permeability and corrosion resistance of the magnetic plate assembly.

[0005] To achieve the above objectives, embodiments of the present invention provide a magnetically conductive plate assembly, comprising: a body portion and a composite coating disposed on the surface of the body portion. The composite coating includes a first coating and a second coating. The first coating is disposed on the surface of the body portion and is composed of a polycrystalline material. The second coating is disposed on the surface of the first coating away from the body portion. The saturation magnetic induction intensity of the first coating is 1.5~3 T, and the charge transfer resistance of the second coating in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 .

[0006] In one embodiment, the average thickness of the first coating is 0.001 to 1 mm.

[0007] In one embodiment, the average thickness of the second coating is 1~20 μm.

[0008] In one embodiment, the average thickness of the body portion is 0.01 to 1 mm.

[0009] In one embodiment, the ratio of the average thickness of the first coating to the average thickness of the body portion is 0.05 to 5.

[0010] In one embodiment, the ratio of the average thickness of the second coating to the average thickness of the first coating is 0.01 to 1.

[0011] In one embodiment, the material of the first coating includes at least one selected from iron, iron alloy, cobalt, cobalt alloy, nickel, and nickel alloy.

[0012] In one embodiment, the material of the second coating includes at least one of nickel, nickel-cobalt alloy, and nickel-phosphorus alloy.

[0013] In one embodiment, the material of the body portion includes at least one of SPCC, iron-cobalt alloy, iron-nickel alloy, silicon steel, iron-based amorphous material, nickel-based amorphous material, and cobalt-based amorphous material.

[0014] In one embodiment, the grain size of the first coating is 0.1~100 μm.

[0015] In one embodiment, the saturation magnetic induction intensity of the first coating is 1 to 6 times that of the saturation magnetic induction intensity of the body portion.

[0016] In one embodiment, the saturation magnetic induction intensity of the body portion is 0.5~3 T.

[0017] In one embodiment, the first coating undergoes an annealing heat treatment at a temperature of 200~1000 °C.

[0018] In one embodiment, an atomic diffusion layer is formed between the body portion and the first coating layer.

[0019] In one embodiment, the critical load for the interfacial bonding force between the first coating and the body is 1~60 N.

[0020] To achieve the above objectives, embodiments of the present invention provide a sound-generating device, the sound-generating device including a housing and a magnetic circuit structure disposed on the housing, the magnetic circuit structure including a magnet assembly and a magnetic guide plate assembly as described above, the magnetic guide plate assembly including at least one of a magnetic guide yoke and a magnetic guide plate disposed at one end of the magnet assembly away from the magnetic guide yoke.

[0021] To achieve the above objectives, embodiments of the present invention provide an electronic device, which includes the magnetic plate assembly described above, or the sound-generating device described above.

[0022] This invention provides a magnetically conductive plate assembly, comprising: a body portion and a composite coating disposed on the surface of the body portion. The composite coating includes a first coating and a second coating. The first coating is disposed on the surface of the body portion and is composed of a polycrystalline material. The second coating is disposed on the surface of the first coating away from the body portion. The saturation magnetic induction intensity of the first coating is 1.5~3T, and the charge transfer resistance of the second coating in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 In this embodiment of the invention, a first coating composed of a polycrystalline material is provided on the surface of the main body. This polycrystalline material possesses microstructural characteristics such as perfect crystallization, regular atomic arrangement, and high atomic packing density, thereby exhibiting excellent structural stability and magnetic property retention. This effectively avoids fluctuations in magnetic permeability caused by the continuous crystallization transformation of amorphous materials during use or temperature rise. As a result, the saturation magnetic induction intensity of the first coating remains stably maintained at a high level of 1.5~3 T over a wide temperature range during the actual operation of the speaker, thus reliably gathering more magnetic lines of force and improving magnetic permeability. Simultaneously, a second coating is provided on the surface of the first coating. This second coating has a strength of 1~200 KΩ·cm in a 3.5 wt.% NaCl solution. 2 The high charge transfer resistance provides excellent corrosion resistance, forming a tight protection for the first coating layer. This prevents the first coating layer from being oxidized and corroded in high-temperature and high-humidity environments, thus avoiding the formation of non-ferromagnetic oxides. It also prevents magnetic lines of force from being blocked by oxides at grain boundaries, allowing the high magnetic permeability of the first coating layer and the inherent structural stability of the polycrystalline material to be maintained for a long time. Ultimately, this ensures that the magnetic plate assembly and magnetic circuit structure have both high and stable magnetic permeability, excellent corrosion resistance, and reliability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the magnetic conductive plate assembly involved in the embodiment of the present invention; Figure 2 This is a schematic diagram of the sound-generating device involved in the embodiment of the present invention; Figure 3 This is a schematic diagram of the mid-frequency acoustic performance test results of the embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures 100. Magnetic plate assembly; 101. Body; 102. Composite coating; 102a, First coating layer; 102b, Second coating layer; 103, Atomic diffusion layer; 101a, Central magnetic plate; 101b, Side magnetic plate; 101c, Magnetic yoke; 200. Sound-generating device; 201. Housing; 202. Magnetic gap; 203. Diaphragm assembly; 204. Voice coil; 205a, center magnet; 205b, side magnet.

[0025] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] Hereinafter, embodiments of the magnetic plate assembly, sound-generating device, and electronic device of the present invention are disclosed in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present invention and are not intended to limit the subject matter of the claims.

[0028] The "range" disclosed in this invention is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0029] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0030] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0032] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0033] This invention provides a magnetic guide plate assembly, with reference to... Figure 1 The magnetic plate assembly 100 includes a body portion 101 and a composite plating layer 102 disposed on the surface of the body portion 101. The composite plating layer 102 includes a first plating layer 102a and a second plating layer 102b. The first plating layer 102a is disposed on the surface of the body portion 101 and is composed of a polycrystalline material. The second plating layer 102b is disposed on the surface of the first plating layer 102a away from the body portion 101. The saturation magnetic induction intensity of the first plating layer 102a is 1.5~3 T, and the charge transfer resistance of the second plating layer 102b in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 .

[0034] Optionally, the first plating layer 102a may be disposed on at least one surface of the body portion 101; for example, the first plating layer 102a may be disposed on at least one of the upper surface, lower surface and side surface of the body portion 101.

[0035] Optionally, the magnetic plate assembly 100 includes at least one of a magnetic yoke and a magnetic plate.

[0036] Optionally, the body part 101 is a basic structural component in the magnetic plate assembly 100 that plays a role in bearing and guiding magnetism, and it is itself a magnetic guiding component in the magnetic circuit structure.

[0037] It should be noted that the magnetic plate assembly 100 in this embodiment of the invention is a magnetically conductive component applied in the magnetic circuit structure of a sound-generating device (e.g., a loudspeaker) and having the aforementioned composite coating 102 on its surface. The magnetic plate assembly 100 can be understood as an integral component formed by the formation of the composite coating 102 on the surfaces of the magnetic yoke (i.e., the frame) and / or the magnetic plate (i.e., the washer) in the magnetic circuit structure of the sound-generating device. That is, the magnetic plate assembly 100 can be an assembly composed of the magnetic yoke and its surface composite coating 102, or it can be an assembly composed of the magnetic plate and its surface composite coating 102, or it can include both. Therefore, the magnetic plate assembly 100 in this embodiment of the invention is not limited to a single component at a specific location, but rather refers generally to a magnetically conductive component with the features of the aforementioned composite coating 102 of this invention on its surface. In this embodiment of the invention, the magnetic plate assembly 100 can function as a magnetic yoke, a magnetic plate, or both, depending on the specific design requirements.

[0038] Optionally, the first coating 102a is disposed on the surface of the body portion 101 and is composed of a polycrystalline material, and the saturation magnetic induction intensity of the first coating 102a is 1.5~3 T; for example, the saturation magnetic induction intensity of the first coating 102a is 1.5 T, 1.6 T, 1.8 T, 2 T, 2.2 T, 2.4 T, 2.5 T, 2.6 T, 2.8 T, 3 T, etc.

[0039] In this embodiment, the polycrystalline material possesses microstructural characteristics such as perfect crystallization, regular atomic arrangement, and high atomic packing density, thereby exhibiting excellent structural stability and magnetic property retention. This effectively avoids the fluctuations in magnetic permeability caused by the continuous crystallization transformation of amorphous materials during use or temperature rise. This ensures that the saturation magnetic induction intensity of the first coating 102a remains stably maintained at a high level of 1.5~3 T over the wide operating temperature range of the loudspeaker, thus reliably gathering more magnetic lines of force and improving magnetic permeability. Therefore, the first coating 102a can be a coating with high saturation magnetic induction intensity. When the saturation magnetic induction intensity of the first coating 102a is less than 1.5 T, the first coating 102a does not sufficiently improve the overall magnetic permeability of the magnetic conductive plate assembly 100. Furthermore, due to limitations in coating technology and alloy composition, it is currently difficult to achieve a saturation magnetic induction intensity higher than 3 T.

[0040] Optionally, the second plating layer 102b is disposed on the surface of the first plating layer 102a away from the body portion 101. For example, if the side of the first plating layer 102a closest to the body portion 101 is taken as the bottom surface of the first plating layer 102a, then the second plating layer 102b can be disposed on the side and / or top surface of the first plating layer 102a.

[0041] Optionally, the charge transfer resistance of the second coating 102b in a 3.5 wt.% NaCl solution is 1~200 KΩ·cm. 2 For example, the charge transfer resistance of the second coating 102b in a 3.5 wt.% NaCl solution is 1 KΩ·cm. 2 10 KΩ·cm 2 20 KΩ·cm 2 40 KΩ·cm 2 50 KΩ·cm 2 60 KΩ·cm 2 80 KΩ·cm 2 100 KΩ·cm 2 120 KΩ·cm 2 140 KΩ·cm 2 160 KΩ·cm 2 180 KΩ·cm 2 200 KΩ·cm 2 wait.

[0042] Optionally, charge transfer resistance reflects the ease of electrochemical reactions at the metal / electrolyte interface. A higher charge transfer resistance means greater resistance to charge transfer from the metal surface to the solution during corrosion, indicating better corrosion resistance of the material. If the charge transfer resistance of the second coating 102b is too low, it is prone to corrosion, failing to protect the first coating 102a, leading to corrosion of the first coating 102a and a sharp decrease in magnetic permeability. Furthermore, theoretically, a higher charge transfer resistance is better, but excessively high resistance usually requires increasing the coating thickness or using more expensive materials. Therefore, in this embodiment of the invention, the charge transfer resistance of the second coating 102b in a 3.5 wt.% NaCl solution is set to 1~200 KΩ·cm. 2 Within this range, it can provide protection for the first coating 102a without affecting the magnetic conductivity or excessively increasing the cost.

[0043] Optionally, the charge transfer resistance can be measured using an electrochemical workstation, with a saturated calomel electrode as the reference electrode and a platinum electrode as the auxiliary electrode. The frequency scan range is 1 MHz to 0.1 Hz, the test equilibrium potential is the open circuit potential, and the perturbation amplitude is ±5 mV.

[0044] Optionally, the magnetic plate assembly 100 can be applied to a sound-generating device, which includes a magnetically conductive structure comprising the magnetic plate assembly 100 and a magnet assembly. The second plating layer 102b can be disposed on the surface of the first plating layer 102a away from the magnet assembly and the body 101; for example, the second plating layer 102b can be disposed on the side of the first plating layer 102a. When the corrosion resistance requirements of the sound-generating device are not high, the bonding surface between the first plating layer 102a of the magnetic plate assembly 100 and the magnet assembly is located inside the sound-generating device and is covered by magnetic circuit adhesive in the middle. Therefore, there is no need to provide an anti-corrosion plating layer (i.e., the second plating layer 102b) to avoid the magnetic shielding effect of the anti-corrosion second plating layer 102b. The surface of the first plating layer 102a that is not bonded to the magnet assembly is exposed and prone to oxidation and corrosion without other protection, resulting in a decrease in magnetic conductivity. Therefore, the second plating layer 102b can be provided to protect it.

[0045] In this embodiment, the second coating 102b can be a corrosion-resistant coating, which has a strength of 1~200 KΩ·cm in a 3.5 wt.% NaCl solution. 2 The high charge transfer resistance provides excellent corrosion resistance, which can form a tight protection for the first coating 102a, preventing it from being oxidized and corroded in high temperature and high humidity environments to produce non-ferromagnetic oxides. It also prevents the magnetic lines of force from being blocked by oxides at the grain boundaries, so that the high magnetic permeability of the first coating 102a and the inherent structural stability of the polycrystalline material can be maintained for a long time. Ultimately, this ensures that the magnetic plate assembly and magnetic circuit structure have both high and stable magnetic permeability, excellent corrosion resistance and reliability.

[0046] In one feasible embodiment, the average thickness of the first coating 102a is 0.001 to 1 mm; for example, the average thickness of the first coating 102a is 0.001 mm, 0.005 mm, 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, etc.

[0047] Optionally, the average thickness of the first coating 102a is 0.1 to 0.3 mm.

[0048] In one feasible embodiment, the average thickness of the body portion 101 is 0.01 to 1 mm; for example, the average thickness of the body portion 101 is 0.01 mm, 0.05 mm, 0.04 mm, 0.06 mm, 0.08 mm, 1 mm, etc.

[0049] In one feasible embodiment, the ratio of the average thickness of the first plating layer 102a to the average thickness of the body portion 101 is 0.05 to 5, that is, the average thickness of the first plating layer 102a is 0.05 to 5 times the average thickness of the body portion 101; for example, the ratio of the average thickness of the first plating layer 102a to the average thickness of the body portion 101 is 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, etc.

[0050] Optionally, the ratio of the average thickness of the first coating 102a to the average thickness of the body portion 101 is 0.1 to 2.

[0051] In this embodiment, if the thickness of the first plating layer 102a is too thin, its proportion in the magnetic conductive plate assembly 100 will be too small, resulting in a weak improvement in magnetic conductivity. If the thickness of the first plating layer 102a is too large, its proportion in the magnetic conductive plate assembly 100 will be too large, leading to excessive internal stress and easy detachment of the first plating layer 102a. If the thickness of the body portion 101 is too thin, its support will be poor, making it difficult for the composite plating layer 102 and the body portion 101 to deform synchronously when the magnetic conductive plate assembly 100 is subjected to external force, and the composite plating layer 102 is prone to cracking or even detachment. If the body portion 101 is too thick, it may reduce the vibration space of the diaphragm assembly in the sound-generating device, affecting the maximum amplitude of the loudspeaker. Therefore, in this embodiment of the invention, the average thickness of the first plating layer 102a is determined to be 0.001~1 mm, the average thickness of the body portion 101 is 0.01~1 mm, and the ratio of the average thickness of the first plating layer 102a to the average thickness of the body portion 101 is 0.05~5.

[0052] In one feasible embodiment, the average thickness of the second coating 102b is 1~20 μm; for example, the average thickness of the second coating 102b is 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, etc.

[0053] In one feasible embodiment, the ratio of the average thickness of the second coating 102b to the average thickness of the first coating 102a is 0.01 to 1; for example, the ratio of the average thickness of the second coating 102b to the average thickness of the first coating 102a is 0.01, 0.05, 0.04, 0.06, 0.08, 1, etc.

[0054] In this embodiment, the second coating 102b is mainly used as an anti-corrosion coating. Therefore, the thicker the coating, the stronger the anti-corrosion ability. However, if the thickness of the second coating 102b is too large, it is equivalent to introducing a layer with poor magnetic permeability or non-magnetic permeability, which will affect the magnetic permeability of the magnetic plate assembly 100. Therefore, this embodiment of the invention controls the thickness of the second coating 102b to achieve synergistic optimization of anti-corrosion performance and magnetic permeability.

[0055] In one feasible embodiment, the material of the first coating 102a includes at least one of iron, iron alloy, cobalt, cobalt alloy, nickel, and nickel alloy.

[0056] In this embodiment, the materials used to form the first coating 102a all have high saturation magnetic induction intensity and excellent ferromagnetic properties, which can effectively gather magnetic lines of force and improve the magnetic permeability of the magnetic plate. Among them, iron and iron alloys have relatively low cost and excellent magnetic permeability, cobalt and cobalt alloys have extremely high saturation magnetic induction intensity and good high-temperature magnetic stability, and nickel and nickel alloys have a certain magnetic permeability while also showing better corrosion resistance than pure iron. Therefore, by selecting one or more of the above materials, it can be ensured that the first coating 102a can fully perform its core function of gathering magnetic lines of force and improving the overall magnetic permeability efficiency.

[0057] In one feasible embodiment, the material of the second coating 102b includes at least one of nickel, nickel-cobalt alloy and nickel-phosphorus alloy.

[0058] In this embodiment, the material of the second coating 102b includes at least one of nickel, nickel-cobalt alloy, and nickel-phosphorus alloy. Among them, the pure nickel coating has low electrochemical activity and is easy to form a dense passivation film in a corrosive environment, thereby providing excellent corrosion resistance. At the same time, nickel atoms themselves have a certain magnetic permeability, which can avoid the additional magnetic reluctance loss caused by traditional non-magnetic protective layers to the magnetic circuit, and thus work with the first coating 102a to further improve the overall magnetic permeability of the magnetic plate assembly 100. The addition of cobalt in the nickel-cobalt alloy can refine the coating grains and reduce grain boundary defects, thereby improving the density and corrosion resistance of the coating. On the other hand, cobalt, as a strong ferromagnetic element, can further improve the saturation magnetic induction intensity of the alloy coating, so that the second coating 102b can actively contribute magnetic permeability while providing protection. The nickel-phosphorus alloy exhibits extremely excellent corrosion resistance due to its amorphous or nanocrystalline structure, and by precisely controlling the phosphorus content in the coating, an ideal balance can be achieved between high corrosion resistance and a certain magnetic permeability.

[0059] In one feasible embodiment, the material of the body portion 101 includes at least one of SPCC, iron-cobalt alloy, iron-nickel alloy, silicon steel, iron-based amorphous material, nickel-based amorphous material, and cobalt-based amorphous material.

[0060] In this embodiment, SPCC (cold-rolled low-carbon steel sheet) has good stamping processability and low cost, making it suitable for mass production and easy to realize complex-shaped magnetic plate assemblies 100; iron-cobalt alloy material has extremely high saturation magnetic induction and Curie temperature, and can maintain excellent magnetic permeability under strong magnetic fields and high temperature environments; iron-nickel alloy material has extremely high initial permeability and low coercivity, making it suitable for weak signal or high-sensitivity magnetic circuit structures. Therefore, by flexibly selecting the above materials, the body 101 can provide an excellent magnetic and structural support foundation for the composite coating 102.

[0061] In one feasible embodiment, the grain size of the first coating 102a is 0.1 to 100 μm. For example, the grain size of the first coating 102a is 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc.

[0062] Optionally, the grain size of the first coating 102a is 1~50 μm.

[0063] In this embodiment, the first coating 102a is a polycrystalline structure. Polycrystalline materials are composed of countless small grains with random orientations. Each grain has its own easy magnetization axis. This allows the polycrystalline structure to avoid the defect of single-crystal materials, which have difficulty in achieving magnetic permeability in both directions due to obvious orientation, when magnetic field lines enter from the vertical direction and exit from the planar direction in such a complex two-dimensional magnetic circuit. This enables faster and more uniform magnetization until saturation in all directions. At the same time, compared with amorphous materials with disordered atomic arrangement and low packing density, polycrystalline materials have perfect crystallization, regular atomic arrangement, and high atomic packing density. More magnetic moments participate in magnetic permeability per unit volume, and the regular arrangement is conducive to the parallel alignment of magnetic moments. Therefore, the saturation magnetic induction intensity is significantly higher than that of amorphous materials. By controlling the grain size of the first coating 102a within the range of 0.1~100 μm, it is possible to avoid excessive grain boundaries caused by excessively small grains, which would lead to excessive pinning of magnetic domains and make magnetization difficult. At the same time, it is possible to prevent excessively large grains from causing a decrease in coating toughness, easy cracking, or even peeling. Thus, while obtaining excellent magnetic properties, the mechanical stability and long-term reliability of the coating are also taken into account.

[0064] In one feasible embodiment, the saturation magnetic induction intensity of the first plating layer 102a is 1 to 6 times that of the saturation magnetic induction intensity of the body portion 101; for example, the saturation magnetic induction intensity of the first plating layer 102a is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 times that of the saturation magnetic induction intensity of the body portion 101.

[0065] In this embodiment, the saturation magnetic induction intensity of the first plating layer 102a is higher than that of the body portion 101. This greatly increases the magnetic permeability of the body portion 101, and at the same time, it eliminates the need to use high-cost materials for the entire body portion 101, thereby effectively reducing costs. The higher the saturation magnetic induction intensity of the first plating layer 102a compared to the body portion 101, the more significant the improvement in the magnetic permeability of the magnetic conductive plate assembly 100. However, when this ratio is too high, the compositional difference between the first plating layer 102a and the body portion 101 becomes too large, resulting in a weaker bonding force between the first plating layer 102a and the body portion 101. Therefore, in this embodiment of the invention, the saturation magnetic induction intensity of the first plating layer 102a is determined to be 1 to 6 times that of the saturation magnetic induction intensity of the body portion 101.

[0066] In one feasible embodiment, the saturation magnetic induction intensity of the body portion 101 is 0.5 to 3 T. For example, the saturation magnetic induction intensity of the body portion 101 is 0.5 T, 1 T, 1.5 T, 2 T, 2.5 T, 3 T, etc.

[0067] In this embodiment, if the saturation magnetic induction intensity of the body portion 101 is too low, the magnetic permeability will be poor, and the body portion 101 will also transmit the magnetic field lines through the first plating layer 102a, making it difficult for the first plating layer 102a to play its role. Furthermore, materials with a saturation magnetic induction intensity higher than 3 T are difficult to produce. Therefore, in this embodiment of the invention, the saturation magnetic induction intensity of the body portion 101 is determined to be 0.5~3T.

[0068] In one feasible embodiment, the critical load for the interfacial bonding force between the first plating layer 102a and the body portion 101 is 1 to 60 N. For example, the critical load for the interfacial bonding force between the first plating layer 102a and the body portion 101 is 1 N, 5 N, 10 N, 15 N, 20 N, 250 N, 30 N, 40 N, 50 N, 60 N, etc.

[0069] Optionally, the interfacial bonding strength can be obtained by scratch testing, for example, by using a Rockwell C diamond indenter to scratch the coating surface while simultaneously applying a vertical normal force, with the load at which the coating continuously peels off as the critical load.

[0070] In this embodiment, if the bonding force between the first plating layer 102a and the body portion 101 is insufficient, the first plating layer 102a is prone to peeling off from the body portion 101, making it difficult to provide stable magnetic conductivity. Excessive interfacial bonding force requires surface treatment of the body portion 101 or prolonged annealing, leading to increased costs and potentially affecting the magnetic properties of both the first plating layer 102a and the body portion 101. Therefore, this embodiment of the invention determines the critical load for the interfacial bonding force between the first plating layer 102a and the body portion 101 to be 1~60 N.

[0071] In one feasible embodiment, the first coating 102a undergoes an annealing heat treatment at a temperature of 200~1000℃. For example, the annealing heat treatment temperature is 200℃, 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, etc.

[0072] Optionally, the first plating layer 102a can be removed together with the body portion 101 to form an atomic diffusion layer 103.

[0073] Optionally, by annealing the first coating 102a in the range of 200~1000 °C, the atoms of the first coating 102a and the atoms of the body 101 acquire sufficient diffusion kinetic energy, and the two migrate and penetrate each other at the interface, thereby forming an atomic diffusion layer 103 with a gradient transition in composition between the body 101 and the first coating 102a. When the heat treatment temperature is below 200 °C, the atomic thermal vibration energy is insufficient to effectively overcome the lattice barrier, and diffusion behavior is difficult to occur, so a diffusion layer with metallurgical bonding characteristics cannot be formed; when the temperature is above 1000 °C, the alloy of the composite coating 102 may undergo an unfavorable phase transformation, and the grains grow excessively, resulting in damage to the coating microstructure and significant deterioration of mechanical and magnetic properties. Within a suitable temperature range of 200~1000℃, ferromagnetic atoms in the first coating 102a diffuse into the lattice of the body 101, while atoms in the body 101 also migrate toward the coating, forming a strong metallurgical bonding layer (i.e., atomic diffusion layer 103).

[0074] In one feasible embodiment, an atomic diffusion layer 103 is formed between the body portion and the first plating layer 102a.

[0075] In this embodiment, the formation of the atomic diffusion layer 103 allows the ferromagnetic atoms of the first plating layer 102a to enter the lattice of the body portion 101, which is equivalent to optimizing the composition of the surface area of ​​the body portion 101, thereby improving the local saturation magnetic induction intensity and magnetic permeability of the body portion 101. At the same time, the atomic diffusion layer 103 eliminates the originally steep interface between the body portion 101 and the first plating layer 102a, forming a transition region with gradually changing magnetic permeability. This allows magnetic lines of force to pass smoothly and with low loss through the interface between the body portion 101 and the first plating layer 102a, avoiding the reflection or scattering of magnetic lines of force caused by abrupt changes in magnetic permeability. This ensures that magnetic lines of force travel smoothly between the body portion 101 and the first plating layer 102a, ultimately achieving a significant improvement in the overall magnetic permeability efficiency of the magnetic conductive plate assembly 100.

[0076] This invention also provides a sound-generating device, which includes a housing and a magnetic circuit structure disposed on the housing. The magnetic circuit structure includes a magnet assembly and a magnetic guide plate assembly as described above. The magnetic guide plate assembly includes at least one of a magnetic guide yoke and a magnetic guide plate disposed at the end of the magnet assembly away from the magnetic guide yoke.

[0077] Optionally, refer to Figure 2 The sound-generating device 200 includes a housing 201 and a magnetic circuit structure disposed on the housing 201. The magnetic circuit structure may include a central magnetic part and a side magnetic part, wherein the central magnetic part and the side magnetic part are spaced apart to form a magnetic gap 202. The sound-generating device 200 also includes a diaphragm assembly 203 and a voice coil 204. One end of the voice coil 204 is connected to the diaphragm assembly 203, and the other end of the voice coil 204 is inserted into the magnetic gap 202, so that when energized, it is driven by the magnetic field to vibrate and generate sound. The central magnetic part includes a central magnet 205a and a central magnetic guide plate 101a, and the side magnetic part includes a side magnet 205b and a side magnetic guide plate 101b. The central magnet 205a and the side magnet 205b together form a magnet assembly to provide magnetic flux to the magnetic circuit. One end of the central magnet 205a is connected to the magnetic yoke 101c, and the other end is connected to the central magnetic plate 101a; one end of the side magnet 205b is connected to the magnetic yoke 101c, and the other end is connected to the side magnetic plate 101b. With this arrangement, the magnetic flux forms a closed loop via the magnetic yoke 101c, the central magnet 205a, the central magnetic plate 101a, the magnetic gap 202, the side magnetic plate 101b, and the side magnet 205b, resulting in a high-intensity magnetic field within the magnetic gap 202, thereby enhancing the driving force of the voice coil 204 and the sensitivity of the sound-generating device 200.

[0078] Optionally, the magnet assembly includes a center magnet 205a and a side magnet 205b.

[0079] Optionally, refer to Figure 2 The surfaces of the central magnetic plate 101a, the side magnetic plates 101b, and the magnetic yoke 101c are provided with the composite coating 102 as described above, so as to achieve synergistic optimization of magnetic conductivity and corrosion resistance.

[0080] Compared with conventional technology, the beneficial effects of the sound-generating device provided in the embodiments of the present invention are the same as those of the magnetic plate assembly provided in the above embodiments, and other technical features in the sound-generating device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0081] This invention also provides an electronic device, including the magnetic plate assembly or sound-generating device described above.

[0082] In this embodiment, electronic devices include mobile phones, laptops, tablets, VR (Virtual Reality) devices, AR (Augmented Reality) devices, TWS (True Wireless Stereo) earphones, smart speakers, smart wearable devices, etc.

[0083] Compared with conventional technology, the beneficial effects of the electronic device provided in the embodiments of the present invention are the same as those of the magnetic conductive plate assembly provided in the above embodiments, and other technical features of the electronic device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0084] To ensure that the details and operations of the above embodiments of the present invention can be clearly understood by those skilled in the art, and to demonstrate the significant advancements in the performance of the embodiments of the present invention, the following examples illustrate the above technical solutions. It should be noted that the following descriptions are merely exemplary and not intended to limit the specific scope of the present invention.

[0085] Example 1 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate with a thickness of 0.11 mm; The composite coating includes: a first coating disposed on the surface of the body portion and a second coating disposed on the top surface of the first coating; The first coating is an iron-cobalt alloy coating (cobalt mass percentage is 50%) with a thickness of 0.11 mm and a saturation magnetic induction intensity of 2.4 T. The first coating and the main body are annealed under argon protection (800 ℃, held for 4 h, then cooled to 23 ℃ in the furnace and taken out). The critical load of the interfacial bonding force between the first coating and the main body is 45 N. The second coating is a nickel-cobalt alloy coating with a thickness of 10 μm; the charge transfer resistance of the second coating in 3.5 wt.% NaCl solution is 125 KΩ*cm. 2 .

[0086] Comparative Example 1 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate with a thickness of 0.22 mm; The coating is a nickel plating with a thickness of 10 μm. The critical load for interfacial adhesion between the coating and the substrate is 30 N. The charge transfer resistance of the coating in 3.5 wt.% NaCl solution is 37 KΩ*cm. 2 .

[0087] Comparative Example 2 A magnetic conductive plate is provided, comprising: The main body is made of iron-cobalt alloy 1J27 with a thickness of 0.22 mm. The coating is a nickel plating with a thickness of 10 μm. The critical load for interfacial adhesion between the coating and the substrate is 27 N. The charge transfer resistance of the coating in 3.5 wt.% NaCl solution is 35 KΩ*cm. 2 .

[0088] In Example 1, the first coating is an iron-cobalt alloy coating with a composition similar to 1J27, exhibiting extremely high saturation magnetic induction. Furthermore, the first coating and the main body are directly bonded through annealing to form a metallurgical bond (i.e., an atomic diffusion layer), resulting in high interfacial adhesion. The second coating is a nickel-cobalt alloy coating. Compared to pure nickel coatings, the addition of cobalt refines the nickel grains, improving corrosion resistance and thus resulting in higher charge transfer resistance and better corrosion resistance. In contrast, Comparative Example 2 uses a 1J27 substrate, which has high hardness and is difficult to stamp. Although the cobalt content of the first coating in Example 1 is similar to that in Comparative Example 2, the iron-cobalt alloy used in Example 1 eliminates the need for smelting, forging, and rolling processes. Therefore, the cost of the magnetic plate in Example 1 is reduced by approximately 45% compared to Comparative Example 2.

[0089] Furthermore, the magnetic plates of Example 1 and Comparative Examples 1-2 were installed in the same loudspeaker, and their acoustic performance was tested. The results are as follows: Figure 3 As shown. According to Figure 3 As can be seen, Example 1 has a significantly higher mid-frequency sensitivity than Comparative Example 1 because it contains a first coating with high saturation magnetic induction intensity. At the same time, the overall composition of the first coating in Example 1 is similar to that of the body of Comparative Example 2. In addition, the second coating is a nickel-cobalt alloy coating, which also provides some magnetic permeability. Therefore, the overall mid-frequency sensitivity of Example 1 is basically the same as that of Comparative Example 2.

[0090] In summary, the magnetic guide plate assembly provided by the embodiments of the present invention can stably conduct magnetism under the conditions of narrow magnetic gap and high magnetic flux density in ultra-thin loudspeakers, reduce magnetic flux loss, and achieve synergistic optimization of magnetic conductivity and corrosion resistance.

[0091] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A magnetic shunt assembly, characterized by, The magnetic conductive plate assembly comprises a body part and a composite plating layer arranged on the surface of the body part, the composite plating layer comprises a first plating layer and a second plating layer, the first plating layer is arranged on the surface of the body part and is composed of a polycrystalline material, the second plating layer is arranged on the surface of the first plating layer away from the body part, the saturation magnetic induction intensity of the first plating layer is 1.5-3 T, and the charge transfer resistance of the second plating layer in a 3.5 wt.% NaCl solution is 1-200 KΩ·cm 2 .

2. The magnetic flux guide plate assembly of claim 1, wherein, The average thickness of the first plating layer is 0.001-1 mm. The average thickness of the second plating layer is 1-20 μm. The average thickness of the body part is 0.01-1 mm. The ratio of the average thickness of the first plating layer to the average thickness of the body part is 0.05-5. The ratio of the average thickness of the second plating layer to the average thickness of the first plating layer is 0.01-1.

3. The magnetic flux guide plate assembly of claim 1, wherein, The material of the first plating layer comprises at least one of iron, iron alloy, cobalt, cobalt alloy, nickel and nickel alloy. The material of the second plating layer comprises at least one of nickel, nickel-cobalt alloy and nickel-phosphorus alloy. The material of the body part comprises at least one of SPCC, iron-cobalt alloy material, iron-nickel alloy material, silicon steel material, iron-based amorphous material, nickel-based amorphous material and cobalt-based amorphous material.

4. The flux guide plate assembly of claim 1, wherein, The grain size of the first plating layer is 0.1-100 μm.

5. The flux guide plate assembly of claim 1, wherein, The saturation magnetic induction of the first plating layer is 1-6 times of the saturation magnetic induction of the body part. The saturation magnetic induction of the body part is 0.5-3 T.

6. The flux guide plate assembly of claim 1, wherein, The first plating layer is subjected to annealing heat treatment, and the temperature of the annealing heat treatment is 200-1000 ℃.

7. The magnetic conducting plate assembly of claim 6, wherein, An atomic diffusion layer is formed between the body part and the first plating layer.

8. The flux guide plate assembly of claim 1, wherein, The critical load of the interface bonding force between the first plating layer and the body part is 1-60 N.

9. A sound producing device, characterized by The sound generating device comprises a shell and a magnetic circuit structure arranged on the shell, the magnetic circuit structure comprises a magnet assembly and a magnetic conducting plate assembly as claimed in any one of claims 1-8, and the magnetic conducting plate assembly comprises at least one of a magnetic conducting yoke and a magnetic conducting plate arranged on the end of the magnet assembly away from the magnetic conducting yoke.

10. An electronic device, comprising: The electronic device comprises a magnetic conducting plate assembly as claimed in any one of claims 1-8, or a sound generating device as claimed in claim 9.

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