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

Abstract

The application discloses a magnetic conducting plate assembly, a sound production device and electronic equipment, and relates to the technical field of acoustics. The application discloses a magnetic conducting plate assembly, which comprises a body part and a plating layer arranged on the surface of the body part. The plating layer comprises a Ni base and Co solid-solved in the Ni base. The plating layer is a face-centered cubic solid-solution polycrystalline structure with Ni as the main body. In terms of mass percentage, the Co content in the plating layer is 3-35 wt.%, the Ni content is 65-97 wt.%, and the total amount of C, O, P, S and unavoidable impurities is less than or equal to 10 wt.%. The hardness of the plating layer is 250-800 Hv. The magnetic conducting plate assembly aims to solve the technical problem of how to improve the magnetic force coefficient Bl value of a loudspeaker while ensuring that the loudspeaker meets the drop performance requirements.

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] As a core sound-generating component in consumer electronics products such as mobile phones and AR (Augmented Reality) glasses, the thickness of loudspeakers is constantly decreasing to keep pace with the trend of ultra-thin and lightweight electronic products. The magnetic circuit structure is a crucial source of driving force for loudspeakers, directly affecting their frequency response characteristics. Typically, the magnetic circuit structure includes a frame (i.e., magnetic yoke, magnetic cup, yoke iron), a magnet mounted on the frame, and a washer (i.e., magnetic plate, pole core) mounted on the magnet. The magnet is a permanent magnet used to provide the magnetic field; the frame and washer are made of soft magnetic materials and serve to conduct the magnetic flux, together forming the magnetic circuit. With the continuous thinning of components such as magnets, frames, and washers, improving the magnetic flux density (Bl) of loudspeakers has become a critical issue in magnetic circuit design. At the same time, as the magnetic components such as the frame become thinner, their structural strength decreases, leading to poorer drop resistance and increased susceptibility to deformation or even failure during drops. Therefore, how to improve the magnetic flux density (Bl) of loudspeakers while ensuring they meet drop performance requirements has become a pressing technical problem to be solved in this field. Summary of the Invention

[0003] 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 ensure that the magnetic coefficient B1 of a loudspeaker meets drop performance requirements while increasing its magnetic force coefficient.

[0004] To achieve the above objectives, embodiments of the present invention provide a magnetic conductive plate assembly, the magnetic conductive plate assembly comprising: a body portion and a plating layer disposed on the surface of the body portion, the plating layer comprising a Ni matrix and Co dissolved in the Ni matrix, the plating layer being a face-centered cubic solid solution polycrystalline structure with Ni as the main body, the Co content in the plating layer being 3~35 wt.%, the Ni content being 65~97 wt.%, the total amount of C, O, P, S and unavoidable impurities being less than or equal to 10 wt.%, and the hardness of the plating layer being 250~800 Hv.

[0005] In one embodiment, the specific saturation magnetization of the coating is 5~250 emu / g.

[0006] In one embodiment, the self-corrosion potential of the coating in a 3.5 wt.% NaCl solution is -0.8 to -0.2 V.

[0007] In one embodiment, the average thickness of the coating is less than or equal to 20% of the average thickness of the body portion.

[0008] In one embodiment, the average thickness of the coating is 1 to 40 μm.

[0009] In one embodiment, the roughness of the coating is 0.01~0.5 μm.

[0010] In one embodiment, the surface energy of the coating is 15~70 mN / m.

[0011] In one embodiment, the coating is annealed at a temperature of 100~1000 °C.

[0012] In one embodiment, the content of Co atoms per unit mass in the coating gradually increases from the side closer to the body portion to the side farther from the body portion. The coating includes a first region closer to the body portion and a second region farther from the body portion. The Co content in the first region is less than or equal to 20 wt.% by mass percentage, the Co content in the second region is greater than or equal to 15 wt.%, and the difference in Co content between the first region and the second region is greater than or equal to 5 wt.%.

[0013] 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.

[0014] In one embodiment, the plating layer in the magnetic conductive plate assembly is disposed on the bonding surface between the magnetic conductive plate assembly and the magnet assembly; Alternatively, the coating may cover all outer surfaces of the magnetic plate assembly.

[0015] 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.

[0016] This invention provides a magnetically conductive plate assembly, comprising: a body and a plating layer disposed on the surface of the body. The plating layer comprises a Ni matrix and Co dissolved in the Ni matrix. The plating layer has a face-centered cubic solid solution polycrystalline structure with Ni as the main component. By mass percentage, the Co content in the plating layer is 1~35 wt.%, the Ni content is 65~99 wt.%, and the total amount of C, O, P, S, and unavoidable impurities is less than or equal to 10 wt.%. The hardness of the plating layer is 250~800 Hv. In this embodiment of the invention, the plating layer has a face-centered cubic solid solution polycrystalline structure with Ni (nickel) as the main component, and Co (cobalt) is dissolved in the Ni matrix. The face-centered cubic structure has many slip systems, which can give the plating layer good plasticity, making it less prone to cracking or peeling under stress; at the same time, the solid solution of Co atoms causes distortion of the Ni lattice, effectively hindering dislocation movement, thereby significantly improving the hardness of the plating layer (250~800 Hv). Furthermore, because the coating has high hardness and is located on the surface of the main body, it can significantly improve the bending resistance and drop deformation resistance of the main body, compensating for the insufficient structural strength caused by the thin design. In addition, by controlling the Co content to 1~35 wt.% and the Ni content to 65~99 wt.%, the coating achieves excellent soft magnetic properties, avoiding the weak magnetic permeability due to excessively low Co content (approaching pure Ni) and the detrimental effect of excessively high Co content (transforming the coating into a hard magnetic material). Moreover, compared to amorphous materials, the polycrystalline structure used in this invention has a high atomic packing density, a high mass ratio of ferromagnetic materials (Ni, Co), more atomic magnetic moments per unit mass, and stronger interatomic exchange coupling, thereby enhancing the magnetic flux density of the magnetic plate assembly and improving the speaker's B1 value. Simultaneously, the polycrystalline structure has perfect crystallization and stable structure, avoiding the fluctuations in magnetic permeability caused by uncontrollable crystallization transformations due to stress or temperature changes during use, ensuring stable and consistent magnetic performance over long-term use. Furthermore, the total amount of C, O, P, S, and unavoidable impurities in the coating is controlled within the range of ≤10 wt.%, which avoids excessive impurities forming metallic inclusions that disrupt lattice continuity and hinder magnetic field conduction, while allowing a small amount of impurity elements to play a positive role in refining grains and increasing hardness. In addition, the NiCo alloy coating also possesses good corrosion resistance, thus preventing a decrease in magnetic permeability due to corrosion and ensuring magnetic circuit continuity. This invention significantly improves the B1 value of the magnetic plate assembly and enhances its resistance to drop deformation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the magnetic conductive plate assembly involved in the embodiments of the present invention; Figure 2 This is a schematic diagram of the coating structure involved in the embodiment of the present invention; Figure 3 This is a schematic diagram of the sound-generating device involved in the embodiment of the present invention; Figure 4 This is a schematic diagram showing the bending test results of the magnetic conductive plate assembly involved in the embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures 100. Magnetic plate assembly; 101. Body; 102. Plating; 103. Co atom; 104a. First region; 104b. Second region; 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.

[0019] 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

[0020] 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.

[0021] 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.

[0022] 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.

[0023] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] This invention provides a magnetic guide plate assembly, with reference to... Figure 1The magnetic plate assembly 100 includes a body portion 101 and a plating layer 102 disposed on the surface of the body portion 101. The plating layer 102 includes a Ni matrix and Co dissolved in the Ni matrix. The plating layer 102 is a face-centered cubic solid solution polycrystalline structure with Ni as the main body. By mass percentage, the Co content in the plating layer 102 is 3~35 wt.%, the Ni content is 65~97 wt.%, and the total amount of C, O, P, S and unavoidable impurities is less than or equal to 10 wt.%. The hardness of the plating layer 102 is 250~800 Hv.

[0028] Optionally, the plating layer 102 may be disposed on at least one surface of the body portion 101; for example, the plating layer 102 may be disposed on at least one of the upper surface, lower surface and side surface of the body portion 101.

[0029] Optionally, the plating 102 can cover all the outer surfaces of the magnetic plate assembly 100, that is, the plating 102 can cover all the outer surfaces of the body portion 101.

[0030] Optionally, the magnetic plate assembly 100 can be applied to a sound-generating device; the sound-generating device includes a housing and a magnetic circuit structure disposed in the housing, the magnetic circuit structure includes a magnet assembly and the magnetic plate assembly 100, and the plating layer 102 in the magnetic plate assembly 100 is disposed on the bonding surface between the magnetic plate assembly 100 and the magnet.

[0031] Optionally, the magnetic plate assembly 100 includes at least one of a magnetic yoke and a magnetic plate.

[0032] 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.

[0033] 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 plating layer 102 on its surface. The magnetic plate assembly 100 can be understood as an integral component formed by the formation of the plating layer 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 plating layer 102, or an assembly composed of the magnetic plate and its surface plating layer 102, or 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 generally refers to a magnetically conductive component with the features of the aforementioned plating layer 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.

[0034] Optionally, the coating 102 includes a Ni (nickel) matrix and Co (cobalt) dissolved in the Ni matrix, and the coating 102 is a face-centered cubic solid solution polycrystalline structure with Ni as the main body.

[0035] It is understandable that the main function of the magnetic plate assembly 100 in the magnetic circuit structure is to conduct magnetism. Therefore, if the plating layer 102 is ordinary pure nickel or chemical nickel, its magnetism is weak or non-magnetic, which will form a "magnetic resistance" between the magnet assembly and the magnetic plate assembly 100 in the magnetic circuit structure. This is equivalent to increasing the magnetic gap between the magnet assembly and the magnetic plate assembly 100, resulting in the dispersion of magnetic lines of force and a decrease in the voice coil driving force. However, the plating layer 102 in this embodiment of the invention is a face-centered cubic solid solution polycrystalline structure with Ni as the main body. The face-centered cubic structure has many slip systems, so the plating layer 102 has good plasticity and is not prone to cracking and deformation. At the same time, Co is at least partially dissolved in the Ni matrix (i.e., the Ni lattice), causing lattice distortion and hindering the movement of dislocations, which can effectively improve the strength and hardness (250~800 Hv) of the plating layer 102. Furthermore, since the coating 102 has high hardness and is located on the surface of the body 101, it can significantly improve the bending resistance and drop deformation resistance of the body 101, thus compensating for the structural strength deficiency caused by the thin design.

[0036] Optionally, the hardness of the coating 102 is 250~800 Hv; for example, the hardness of the coating 102 is 250 Hv, 300 Hv, 350 Hv, 400 Hv, 450 Hv, 500 Hv, 550 Hv, 600 Hv, 650 Hv, 700 Hv, 750 Hv, 800 Hv, etc.

[0037] In this embodiment, the body 101 generally serves as the carrier of the magnetic circuit structure, exposed outside the speaker unit, and bears significant stress during reliability tests such as drop tests. It is typically made of SPCC or iron-cobalt alloy material; however, to accommodate the stamping process, its hardness generally does not exceed 200 Hv, making it prone to deformation under stress. When the plating 102 has higher hardness, it forms a laminated structure with the body 101, significantly increasing its ability to withstand bending stress. However, when the plating 102 is too hard, its toughness decreases significantly, making it difficult for the surface plating 102 to deform synchronously with the softer body 101 under stress, leading to cracks or even peeling of the plating 102. Therefore, in this embodiment, the hardness of the plating 102 is determined to be 250~800 Hv.

[0038] Optionally, the NiCo alloy coating 102 is a magnetic coating. By adjusting the Co content, excellent soft magnetic properties can be obtained, ensuring magnetic circuit continuity and improving magnetic permeability and focusing ability. In this embodiment of the invention, the Co content in the coating 102 is 3~35 wt.% by mass percentage; for example, the Co content in the coating 102 is 3 wt.%, 5 wt.%, 8 wt.%, 10 wt.%, 13 wt.%, 15 wt.%, 17 wt.%, 20 wt.%, 23 wt.%, 25 wt.%, 27 wt.%, 30 wt.%, 33 wt.%, 35 wt.%, etc. The Ni content in coating 102 is 65~97 wt.%; for example, the Ni content in coating 102 is 65 wt.%, 67 wt.%, 70 wt.%, 72 wt.%, 75 wt.%, 78 wt.%, 80 wt.%, 83 wt.%, 85 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, etc.

[0039] In this embodiment, if the Co content in the coating 102 is too low (e.g., <3 wt.%), the properties of the coating 102 are similar to pure Ni, and its magnetic permeability is low; while if the Co content in the coating 102 is too high, the coating 102 will transform into a hard magnetic material, which is not conducive to magnetic permeability. Furthermore, Co is a precious metal material, and its cost is high. Therefore, in this embodiment of the invention, the Co content in the coating 102 is determined to be 3~35 wt.%, and the Ni content is 65~97 wt.%, so that the coating obtains excellent soft magnetic properties.

[0040] Optionally, the total amount of C, O, P, S, and unavoidable impurities in the coating 102 is less than or equal to 10 wt.%, for example, less than or equal to 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, etc. This avoids excessive impurities forming metallic inclusions that disrupt lattice continuity and hinder magnetic field conduction, while allowing a small amount of impurity elements to play a positive role in refining grains and improving hardness.

[0041] Optionally, if the body 101 is made of iron-based alloys such as SPCC or FeCo alloy, it is easy to form iron oxide or other oxides, which will cause the magnetic permeability to drop rapidly. Therefore, the coating 102 needs to have anti-corrosion properties. The NiCo alloy coating 102 selected in this embodiment of the invention has good anti-corrosion properties, so it can avoid the drop in magnetic permeability caused by corrosion and ensure the continuity of the magnetic circuit.

[0042] Optionally, compared to amorphous materials, the polycrystalline structure used in this embodiment of the invention has a high atomic packing density and a high mass percentage of ferromagnetic materials (Ni, Co). In the coating 102, the mass percentage of Ni and Co can be controlled to be above 90 wt.%, while conventional amorphous materials generally have less than 80 wt.% of ferromagnetic elements. The higher the proportion of ferromagnetic elements, the more atomic magnetic moments are contained in the coating 102, the stronger the interatomic interactions, and the better the magnetic permeability. Simultaneously, the polycrystalline structure has perfect crystallization and stable structure, which can avoid the fluctuations in magnetic permeability caused by uncontrollable crystallization transformations due to stress or temperature changes during the use of amorphous materials, ensuring stable and consistent magnetic performance over long-term use.

[0043] In this embodiment, the coating 102 is a face-centered cubic solid solution polycrystalline structure with Ni as the main component, and Co (cobalt) is dissolved in the Ni matrix. The face-centered cubic structure has many slip systems, which can endow the coating 102 with good plasticity, making it less prone to cracking or peeling under stress; at the same time, the solid solution of Co atoms causes distortion of the Ni lattice, effectively hindering dislocation movement, thereby significantly improving the hardness of the coating 102 (250~800 Hv). Furthermore, since the coating 102 has high hardness and is located on the surface of the body 101, it can greatly improve the bending resistance and drop deformation resistance of the body 101, compensating for the insufficient structural strength caused by the thin design. Furthermore, in this embodiment of the invention, by controlling the Co content to 1~35 wt.% and the Ni content to 65~99 wt.%, the coating 102 achieves excellent soft magnetic properties. This avoids the magnetic permeability being too weak due to excessively low Co content (approaching pure Ni) and also avoids the coating 102 transforming into a hard magnetic material due to excessively high Co content, which would be detrimental to magnetic permeability. Moreover, compared to amorphous materials, the polycrystalline structure used in this embodiment of the invention has a high atomic packing density, a high mass ratio of ferromagnetic materials (Ni, Co), more atomic magnetic moments per unit mass, and stronger interatomic exchange coupling, thereby enhancing the magnetic flux density of the magnetic plate assembly 100 and improving the speaker B1 value. At the same time, the polycrystalline structure has perfect crystallization and stable structure, which can avoid the fluctuations in magnetic permeability caused by uncontrollable crystallization transformations due to stress or temperature changes during use of amorphous materials, ensuring stable and consistent magnetic performance during long-term use. Furthermore, the total amount of C, O, P, S, and unavoidable impurities in the coating 102 is controlled within the range of ≤10 wt.%, which avoids excessive impurities forming metallic inclusions that disrupt lattice continuity and hinder magnetic field conduction, while allowing a small amount of impurity elements to play a positive role in refining grains and increasing hardness. In addition, the NiCo alloy coating 102 also possesses good corrosion resistance, thus preventing a decrease in magnetic permeability due to corrosion and ensuring magnetic circuit continuity. This embodiment of the invention significantly improves the B1 value of the magnetic plate assembly 100 and enhances its resistance to drop deformation.

[0044] In one feasible embodiment, the specific saturation magnetization of the coating 102 is 5 to 250 emu / g; for example, the specific saturation magnetization of the coating 102 is 5 emu / g, 10 emu / g, 15 emu / g, 20 emu / g, 25 emu / g, 30 emu / g, 35 emu / g, 50 emu / g, 60 emu / g, 70 emu / g, 80 emu / g, 90 emu / g, 100 emu / g, 110 emu / g, 120 emu / g, 150 emu / g, 160 emu / g, 180 emu / g, 200 emu / g, etc.

[0045] Optionally, the specific saturation magnetization of the coating 102 is 50~250 emu / g.

[0046] Optionally, specific saturation magnetization refers to the magnitude of the magnetic moment per unit mass of material after it has been magnetized to saturation in a sufficiently large external magnetic field. Specific saturation magnetization can be tested using a vibrating sample magnetometer, with a test magnetic field range of -10000 to 10000 Oe. Higher specific saturation magnetization results in a greater magnetic moment per unit mass and better magnetic permeability. However, higher specific saturation magnetization also places higher demands on the material's crystal structure and composition, making its preparation more difficult.

[0047] In this embodiment, the plating layer 102 in the magnetic plate assembly 100 is a polycrystalline material, which has the characteristics of perfect crystallization, regular atomic arrangement, and high atomic packing density. Compared with amorphous materials, which usually require the addition of a large amount of non-magnetic elements such as boron, silicon, and phosphorus to maintain the amorphous state, resulting in a low content of ferromagnetic materials, the polycrystalline material used in this embodiment of the invention can accommodate a higher proportion of ferromagnetic materials. The higher the proportion of ferromagnetic materials, the more atomic magnetic moments are contained in the plating layer 102, the stronger the exchange coupling between atoms, and the better the magnetic conductivity.

[0048] Optionally, the higher the specific saturation magnetization of the coating 102, the higher the cobalt content in the coating 102, but the higher the cost.

[0049] In one feasible embodiment, the self-corrosion potential of the coating 102 in a 3.5 wt.% NaCl solution is -0.8 to -0.2 V. For example, the self-corrosion potential of the coating 102 in a 3.5 wt.% NaCl solution is -0.8 V, -0.7 V, -0.6 V, -0.5 V, -0.4 V, -0.3 V, -0.2 V, etc.

[0050] Optionally, the self-corrosion potential represents the corrosion tendency of a material in a 3.5 wt.% NaCl solution, wherein the more positive the potential, the less likely the material is to lose electrons, and the higher the corrosion resistance of the material.

[0051] Optionally, the self-corrosion potential can be obtained using a Tafel curve. The test was conducted using a three-electrode system in an electrochemical analyzer, with a platinum sheet as the auxiliary electrode, a saturated calomel electrode as the reference electrode, and the sample as the working electrode. The test solution was a 3.5 wt.% NaCl solution. Since the electrode potential of the reference electrode is known, the electrode potential of the test electrode can be calculated, and then the relationship curve between current and electrode potential, i.e., the polarization curve, can be obtained. The corrosion potential is then calculated using the Tafel extrapolation method.

[0052] In this embodiment, if the self-corrosion potential of the coating 102 is lower than -0.8 V, the coating 102 has poor corrosion resistance and is difficult to provide protection. Therefore, this embodiment of the invention determines that the self-corrosion potential of the coating 102 in a 3.5 wt.% NaCl solution is -0.8 to -0.2 V, giving it excellent corrosion resistance.

[0053] In one feasible embodiment, the average thickness of the coating 102 is less than or equal to 20% of the average thickness of the body portion 101; for example, the average thickness of the coating 102 is less than or equal to 20%, 18%, 16%, 15%, 14%, 12%, 10%, 8%, 6%, 5%, etc. of the average thickness of the body portion 101.

[0054] In one feasible embodiment, the average thickness of the coating 102 is 1 to 40 μm; for example, the average thickness of the coating 102 is 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, etc.

[0055] Optionally, the average thickness of the coating 102 is 3~30 μm.

[0056] In this embodiment, the thicker the coating 102, the better its corrosion resistance. However, if the coating 102 is too thick, the overall thickness of the magnetic circuit structure increases, the magnetic lines of force travel longer, and the magnetic permeability deteriorates. Furthermore, if the overall thickness is too large, the vibration space of the diaphragm decreases, affecting the amplitude of the speaker. Moreover, the coating 102 contains significant internal stress. When the body portion 101 is too thin, it is difficult for the body portion 101 to resist the deformation caused by the internal stress of the coating 102, resulting in bending deformation. This causes microcracks in the hard coating 102, reducing its corrosion resistance and even causing the coating 102 to peel off. The coating 102 in this embodiment of the invention has good corrosion resistance. Therefore, this embodiment of the invention can achieve good corrosion resistance when the average thickness of the coating 102 is less than or equal to 20% of the thickness of the body portion 101, and the average thickness of the coating 102 is within the range of 1~40 μm.

[0057] In one feasible embodiment, the roughness of the coating 102 is 0.01~0.5 μm; for example, the roughness of the coating 102 is 0.01 μm, 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, etc.

[0058] Optionally, the roughness of the coating 102 is 0.05~0.3 μm.

[0059] Optionally, the coating 102 includes a Ni matrix and Co dissolved in the Ni matrix. Since the Co element has the effect of grain refinement, the coating 102 has a smaller surface roughness.

[0060] In this embodiment, the coating 102 is typically bonded to other components (e.g., magnets) in the magnetic structure of the sound-generating device using an adhesive. Therefore, if the roughness of the coating 102 is too low, its contact area with the adhesive is small, resulting in insufficient anchoring and weak adhesion. Conversely, if the roughness of the coating 102 is too high, the adhesive layer formed by the adhesive cannot completely wet the troughs in the coating 102, and stress concentration is easily formed at the peaks in the coating 102, affecting the bonding effect. Therefore, in this embodiment of the invention, the roughness of the coating 102 is determined to be 0.01~0.5 μm.

[0061] In one feasible embodiment, the surface energy of the coating 102 is 15~70 mN / m. For example, the surface energy of the coating is 15 mN / m, 20 mN / m, 25 mN / m, 30 mN / m, 35 mN / m, 40 mN / m, 45 mN / m, 50 mN / m, 55 mN / m, 60 mN / m, 65 mN / m, 70 mN / m, 75 mN / m, etc.

[0062] In this embodiment, surface energy determines the adhesive performance of the coating 102. The higher the surface energy of the coating 102 (for example, when the surface energy of the coating 102 is greater than the surface tension of the adhesive), the easier it is for the adhesive to spread on the surface of the coating 102, achieving good wetting properties and improving the adhesion between the coating 102 and the magnet assembly. However, the surface energy should not be too high. When the surface energy is too high, the adhesive spreads too quickly on the surface of the coating 102, making it difficult to maintain a certain thickness, which will also affect the adhesive strength. Therefore, in this embodiment of the invention, the surface energy of the coating 102 is determined to be 15~70 mN / m to ensure good adhesive strength.

[0063] In one feasible embodiment, the coating 102 is annealed at a temperature of 100~1000℃. For example, the annealing temperature is 100℃, 200℃, 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, etc.

[0064] In this embodiment, annealing provides energy to the atoms at the interface between the body 101 and the coating 102, promoting the diffusion of elements such as Fe in the body 101 and Ni and Co in the coating 102, forming a metallurgical diffusion layer, which significantly improves the bonding force between the coating 102 and the body 101. However, when the annealing temperature is below 100 °C, the driving force for atomic diffusion is insufficient, and there is no significant effect on improving the bonding force. When the annealing temperature is too high, large grains will devour small grains during the annealing process, forming even larger grains. According to the Hall-Petch effect, the larger the grain size, the lower the hardness. Therefore, in this embodiment of the invention, the annealing temperature is controlled to be no higher than 1000 °C.

[0065] In one feasible implementation, refer to Figure 2 The content of Co atoms 103 per unit mass in the coating 102 gradually increases from the side closer to the body portion 101 to the side farther away from the body portion 101. The coating 102 includes a first region 104a close to the body portion 101 and a second region 104b far away from the body portion 101. The Co content of the first region 104a is less than or equal to 20 wt.% by mass percentage, the Co content of the second region 104b is greater than or equal to 15 wt.%, and the difference in Co content between the first region 104a and the second region 104b is greater than or equal to 5 wt.%.

[0066] In this embodiment, the cobalt content in the coating 102 exhibits a gradient distribution, gradually increasing from the side closer to the body portion 101 to the side farther from the body portion 101. This effectively optimizes the residual stress distribution within the coating 102, allowing the stress to transition smoothly from the side closer to the body portion 101 to the surface side, thereby avoiding problems such as coating 102 peeling, cracking, or decreased interfacial adhesion caused by sudden stress changes. On the side closer to the body portion 101, since the body portion 101 (such as SPCC or iron-cobalt alloy) has a lower elastic modulus and lower hardness, using a lower cobalt content (such as no more than 20 wt.%) allows the hardness of the coating 102 to better match that of the body portion 101, resulting in better toughness and lower internal stress in the coating 102. This significantly improves the bonding strength between the coating 102 and the body portion 101, reducing the risk of interfacial peeling. Using a higher cobalt content (e.g., not less than 15 wt.%) on the side away from the body 101 allows the excellent corrosion resistance and solid solution strengthening effect of cobalt to give the coating 102 a higher hardness and a denser, more stable oxide film, thereby significantly improving the overall corrosion resistance, wear resistance, and scratch resistance of the coating 102. Furthermore, using a higher cobalt content on the side away from the body 101, i.e., the second region 104b, helps to increase the saturation magnetic induction intensity of the coating 102 and enhance the magnetic permeability of the magnetic circuit system. Conversely, using a lower cobalt content on the side closer to the body 101, i.e., the first region 104a, helps to maintain good toughness and low stress, ensuring that the coating 102 does not develop fatigue cracks under long-term use. At the same time, if the difference in Co content between the first region 104a and the second region 104b is too small, it is difficult to form an effective performance gradient, the improvement effect on internal stress distribution is not significant, and it is difficult to simultaneously meet the dual requirements of low stress bonding, high surface hardness, and high corrosion resistance. Therefore, the embodiments of the present invention achieve a comprehensive technical effect of optimizing internal stress, enhancing adhesion, improving surface hardness, improving corrosion resistance, and synergistically enhancing magnetic permeability of coating 102 through gradient design of cobalt content.

[0067] 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.

[0068] Optionally, refer to Figure 3The 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.

[0069] Optionally, refer to Figure 3 The surfaces of the central magnetic plate 101a, the side magnetic plates 101b, and the magnetic yoke 101c are provided with the coating 102 as described above, thereby achieving synergistic optimization of magnetic conductivity and corrosion resistance.

[0070] In one possible embodiment, a plating layer 102 in the magnetic plate assembly 100 is disposed on the bonding surface between the magnetic plate assembly 100 and the magnet assembly.

[0071] In this embodiment, since the bonding surface between the magnetic plate assembly 100 and the magnet assembly is the key interface for the transmission of magnetic flux from the magnet to the magnetic plate assembly, when the high permeability plating layer 102 of this embodiment is disposed on the bonding surface between the magnetic plate assembly 100 and the magnet assembly, the magnetic resistance caused by oxidation or poor contact of the body part 101 can be effectively eliminated, ensuring smooth passage of magnetic lines of force, thereby significantly improving the magnetic permeability efficiency and B1 value of the magnetic circuit system. At the same time, plating only a local area can reduce the material consumption of the plating layer 102 and the accumulation of internal stress, avoiding unnecessary impact on non-functional surfaces.

[0072] In one possible embodiment, the plating 102 covers all the outer surfaces of the magnetic plate assembly 100, that is, the plating 102 covers all the outer surfaces of the body portion 101.

[0073] In this embodiment, when the coating 102 covers all the outer surfaces of the magnetic plate assembly 100, it can provide the magnetic plate assembly 100 with all-round anti-corrosion protection and structural reinforcement, significantly improving its bending resistance and drop deformation resistance, and achieving closed protection.

[0074] 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.

[0075] This invention also provides an electronic device, including the magnetic plate assembly or sound-generating device described above.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] Example 1 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is a nickel-cobalt alloy coating applied to the surface of the body, comprising a Ni matrix and Co dissolved in the Ni matrix. The coating has a face-centered cubic solid solution polycrystalline structure with Ni as the main body. The average thickness of the coating is 8 μm, and the Co content in the coating is 27 wt.% by mass.

[0080] Example 2 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is a nickel-cobalt alloy coating applied to the surface of the body, comprising a Ni matrix and Co dissolved in the Ni matrix. The coating has a face-centered cubic solid solution polycrystalline structure with Ni as the main component. The average thickness of the coating is 8 μm. The content of Co atoms per unit mass in the coating gradually increases from the side closer to the body to the side farther away from the body. The coating includes a first region closer to the body and a second region farther away from the body, wherein, by mass percentage, the Co content of the first region is 5 wt.% and the Co content of the second region is 32 wt.%.

[0081] Comparative Example 1 A magnetic conductive plate is provided, comprising: The body part is made of SPCC substrate.

[0082] Comparative Example 2 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The plating is a pure nickel plating applied to the surface of the body, with an average thickness of 8 μm.

[0083] The magnetic plates of Examples 1-2 and Comparative Examples 1-2 were tested, and the results are shown in Table 1 below: Table 1

[0084] Based on the test results above, it can be seen that the coatings in Examples 1 and 2 contain Co, which forms a substitutional solid solution with Ni. Since the atomic radius of Co is larger than that of Ni, the addition of Co distorts the Ni lattice, resulting in a solid solution strengthening effect and affecting dislocation movement. Therefore, Examples 1 and 2 show a significant increase in hardness compared to the pure nickel coating (Comparative Example 2) and the uncoated coating (Comparative Example 1). Example 2 uses a gradient-distributed coating; the coating on the surface furthest from the body has a higher Co content, thus resulting in higher hardness than Example 1.

[0085] Furthermore, since Co has a superior atomic magnetic moment compared to Ni, and due to the interaction between the two, the addition of Co in Examples 1 and 2 significantly increases the specific saturation magnetization of the coating. In addition, the addition of Co allows for the formation of a NiCo mixed oxide film on the coating surface, and the higher Co content on the coating surface of Example 2 promotes grain refinement, producing more grain boundaries and resulting in better oxide film density, thus exhibiting a higher self-corrosion potential and better corrosion resistance. Simultaneously, the refined grains near the surface of the coating in Example 2 provide moderate roughness and surface energy, which is beneficial for adhesive bonding.

[0086] Furthermore, bending tests were conducted on the magnetic plates of Example 1 and Comparative Example 2, and the results are as follows: Figure 4As shown, under the same displacement, Example 1 has a higher load, can withstand higher bending stress, and has better resistance to deformation.

[0087] Furthermore, the magnetic plates of Example 1 and Comparative Example 2 were assembled into the same loudspeaker, and their magnetic coefficient Bl value was tested. The value of Bl in Example 1 was 0.882 T / m, and that in Comparative Example 2 was 0.877 T / m. It can be seen that the Bl value was significantly improved, the voice coil had a greater driving force, and the sensitivity was higher.

[0088] In summary, the magnetic plate assembly provided in this embodiment of the invention can improve the B1 value of the magnetic plate assembly and enhance its resistance to drop deformation.

[0089] 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 conductive plate assembly, characterized in that, The magnetic plate assembly includes a body and a plating layer disposed on the surface of the body. The plating layer includes a Ni matrix and Co dissolved in the Ni matrix. The plating layer has a face-centered cubic solid solution polycrystalline structure with Ni as the main body. By mass percentage, the Co content in the plating layer is 3~35 wt.%, the Ni content is 65~97 wt.%, and the total amount of C, O, P, S and unavoidable impurities is less than or equal to 10 wt.%. The hardness of the plating layer is 250~800 Hv.

2. The magnetic conductive plate assembly as described in claim 1, characterized in that, The specific saturation magnetization of the coating is 5~250 emu / g.

3. The magnetic conductive plate assembly as described in claim 1, characterized in that, The self-corrosion potential of the coating in 3.5 wt.% NaCl solution is -0.8 to -0.2 V.

4. The magnetic plate assembly as claimed in claim 1, characterized in that, The average thickness of the coating is less than or equal to 20% of the average thickness of the body portion; And / or, the average thickness of the coating is 1~40 μm.

5. The magnetic conductive plate assembly as claimed in claim 1, characterized in that, The roughness of the coating is 0.01~0.5 μm; And / or, the surface energy of the coating is 15~70 mN / m.

6. The magnetic plate assembly as claimed in claim 1, characterized in that, The coating is annealed at a temperature of 100~1000 ℃.

7. The magnetic plate assembly as claimed in claim 1, characterized in that, The content of Co atoms per unit mass in the coating gradually increases from the side closer to the body portion to the side farther away from the body portion. The coating includes a first region closer to the body portion and a second region farther away from the body portion. The Co content in the first region is less than or equal to 20 wt.% by mass percentage, the Co content in the second region is greater than or equal to 15 wt.%, and the difference in Co content between the first region and the second region is greater than or equal to 5 wt.%.

8. A sound-generating device, characterized in that, The sound-generating device 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 in any one of claims 1 to 7. The magnetic guide plate assembly includes 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.

9. The sound-generating device as described in claim 8, characterized in that, The plating layer in the magnetic conductive plate assembly is provided on the bonding surface between the magnetic conductive plate assembly and the magnet; Alternatively, the coating may cover all outer surfaces of the magnetic plate assembly.

10. An electronic device, characterized in that, The electronic device includes a magnetic plate assembly as described in any one of claims 1 to 7, or a sound-generating device as described in claim 8 or 9.

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