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, relates to the technical field of acoustics, and discloses a magnetic conducting plate assembly, which comprises a body part and a plating layer arranged on the surface of the body part, wherein the plating layer comprises a ferromagnetic material, the ferromagnetic material is a polycrystalline material, the ferromagnetic material at least comprises a first component material and a second component material, the first component material is nickel, and the second component material is at least one of iron and cobalt, wherein the mass proportion of the ferromagnetic material in the plating layer is 90-100 %, and the specific saturation magnetization of the plating layer is greater than or equal to 5 emu / g. The magnetic conducting plate assembly solves the technical problem that the existing loudspeaker is difficult to simultaneously meet the dual requirements of high magnetic conductivity and high reliability.

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] With the trend towards thinner and lighter consumer electronics, the thickness of loudspeakers, as the core sound-generating component in electronic devices such as mobile phones and AR glasses, is also decreasing. The magnetic circuit structure is the main source of the loudspeaker's driving force and directly affects its frequency response characteristics. Typically, the magnetic circuit structure of a loudspeaker 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 field, together forming the magnetic circuit. With the continuous thinning of components such as magnets, frames, and washers, ensuring the magnetic field strength in the magnetic gaps has become a crucial issue in magnetic circuit design.

[0003] Currently, speaker frames and washers typically use soft magnetic materials such as SPCC (cold-rolled steel sheet) or iron-cobalt alloys. To meet reliability requirements in environments such as salt spray, high temperature, and high humidity, their surfaces are generally plated with a 3-10 μm thick chemical high-phosphorus nickel plating. However, chemical high-phosphorus nickel plating has poor magnetic permeability, which significantly affects the mid-frequency performance of the speaker. While electroplated pure nickel has some magnetic permeability, nickel has a low specific saturation magnetization and generally poor corrosion resistance. Therefore, it is also difficult to simultaneously meet the dual requirements of high magnetic permeability and high reliability. 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, which aims to solve the technical problem that existing loudspeakers cannot simultaneously meet the dual requirements of high magnetic permeability and high reliability.

[0005] To achieve the above objectives, embodiments of the present invention provide a magnetically conductive plate assembly, the magnetically conductive plate assembly comprising: a body portion and a plating layer disposed on the surface of the body portion, the plating layer comprising a ferromagnetic material, the ferromagnetic material being a polycrystalline material, the ferromagnetic material comprising at least a first component material and a second component material, the first component material being nickel, and the second component material being at least one of iron and cobalt, wherein the mass percentage of the ferromagnetic material in the plating layer is 90~100%, and the specific saturation magnetization of the plating layer is greater than or equal to 5 emu / g.

[0006] In one embodiment, if the second constituent material is cobalt, then the mass percentage of the second constituent material in the ferromagnetic material is 3-50%.

[0007] In one embodiment, if the second constituent material is iron, then the mass percentage of the second constituent material in the ferromagnetic material is 3-40%.

[0008] In one embodiment, if the second constituent material is cobalt and iron, the mass percentage of the second constituent material in the ferromagnetic material is 5-50%, wherein the mass percentage of iron is less than or equal to 40%.

[0009] In one embodiment, the average corrosion rate of the coating in a 5% NaCl solution is 0.01~20 mg / m². 2 ·h.

[0010] In one embodiment, the average thickness of the coating is less than or equal to 20% of the average thickness of the body portion.

[0011] In one embodiment, the average thickness of the coating is 1 to 50 μm.

[0012] In one embodiment, the adhesion force between the coating and the body portion is 4~5 B.

[0013] In one embodiment, the roughness of the coating is 0.01~1 μm.

[0014] In one embodiment, the water contact angle of the coating is 30° to 140°.

[0015] In one embodiment, the coating is passivated, and the passivation treatment includes at least one of chromate passivation, molybdate passivation, tungstate passivation, titanate passivation, silicate passivation, phytic acid passivation, and tannic acid passivation.

[0016] In one embodiment, the coating is subjected to a sealing treatment, and the sealing agent used in the sealing treatment includes at least one of an aqueous sealing agent, an oil-based sealing agent, and a nanocomposite sealing agent.

[0017] In one embodiment, the saturation magnetic moment of the magnetic plate assembly is 1 to 50% higher than that of the body portion.

[0018] 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.

[0019] 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.

[0020] This invention provides a magnetic conductive plate assembly, comprising: a body portion and a coating disposed on the surface of the body portion. The coating includes a ferromagnetic material, which is a polycrystalline material. The ferromagnetic material includes at least a first component material and a second component material. The first component material is nickel, and the second component material is at least one of iron and cobalt. The ferromagnetic material accounts for 90-100% of the mass of the coating, and the specific saturation magnetization of the coating is greater than or equal to 5 emu / g. In this invention, the coating in the magnetic conductive plate assembly is a polycrystalline material, possessing characteristics such as perfect crystallization, regular atomic arrangement, and high atomic packing density. Compared to amorphous materials, which typically require the addition of large amounts of non-magnetic elements such as boron, silicon, and phosphorus to maintain their amorphous state, resulting in a lower ferromagnetic material content, the polycrystalline material used in this invention can accommodate a higher proportion of ferromagnetic material. Therefore, the mass percentage of ferromagnetic material in the coating can reach as high as 90-100%. A higher proportion of ferromagnetic material results in more atomic magnetic moments in the coating, stronger exchange coupling between atoms, and superior magnetic conductivity. Meanwhile, polycrystalline materials exhibit perfect crystallization and good structural stability, effectively avoiding the fluctuations in magnetic permeability caused by the continuous crystallization transformation of amorphous materials during use or temperature rise. This ensures the long-term consistency of the coating's magnetic properties within the actual operating temperature range of the loudspeaker. Furthermore, the ferromagnetic material in the coating includes at least nickel (the first component) and at least one of iron or cobalt (the second component). Iron, cobalt, and nickel atoms possess numerous unpaired electrons in their 3d electron shells, endowing each atom with a strong atomic magnetic moment. When adjacent atomic electron clouds overlap, strong exchange coupling occurs, causing the unpaired electron spins to tend towards parallelism, spontaneously forming neatly arranged magnetic domains within the microscopic region. Under the influence of an external magnetic field, these domains align in an orientation, exhibiting strong macroscopic magnetism. Through this ferromagnetic mechanism, the coating itself can become an effective component of the magnetic circuit, rather than a magnetoresistance barrier. Simultaneously, nickel possesses excellent corrosion resistance, providing basic corrosion protection for the coating. Iron and cobalt have similar molar masses and densities to nickel, thus forming an infinite solid solution with each other, ensuring the density and compositional uniformity of the coating structure. In this embodiment of the invention, the specific saturation magnetization of the coating is not less than 5 emu / g, which enables it to have effective anti-magnetic saturation capability. It 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. Attached Figure Description

[0021] 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 3This is a schematic diagram of the saturation magnetic moment test results involved in the embodiments of the present invention; Figure 4 This is a schematic diagram of the mid-frequency acoustic performance test results of the embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures 100. Magnetic plate assembly; 101. Body; 102. Plating; 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.

[0023] 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

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 ferromagnetic material, which is a polycrystalline material. The ferromagnetic material includes at least a first component material and a second component material. The first component material is nickel, and the second component material is at least one of iron and cobalt. The mass percentage of the ferromagnetic material in the plating layer 102 is 90-100%, and the specific saturation magnetization of the plating layer 102 is greater than or equal to 5 emu / g.

[0032] 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.

[0033] Optionally, the magnetic plate assembly 100 includes at least one of a magnetic yoke and a magnetic plate.

[0034] 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.

[0035] 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.

[0036] Optionally, the coating 102 includes a ferromagnetic material, which includes at least a first component material and a second component material, wherein the first component material is nickel and the second component material is at least one of iron and cobalt.

[0037] In this embodiment, the body portion 101 is typically made of SPCC or iron-cobalt alloy, which has poor corrosion resistance. Therefore, this embodiment of the invention provides a magnetically conductive alloy plating layer 102 with better corrosion resistance on the surface of the body portion 101. The plating layer 102 contains ferromagnetic materials such as nickel and at least one of iron and cobalt. Iron, cobalt, and nickel atoms have a large number of unpaired electrons in the 3d electron shell, which endow each ferromagnetic atom with a strong "atomic magnetic moment." When the electron clouds of adjacent atoms overlap, a strong interaction force is generated between the atoms. This exchange force tends to keep the spin directions of the unpaired electrons of adjacent atoms parallel. Due to this strong exchange effect, within a small region, the magnetic moments of all atoms spontaneously align neatly, forming a magnetic domain. Under the influence of an external magnetic field, all magnetic domains are uniform, thus exhibiting strong macroscopic magnetism. Through the above-described ferromagnetic mechanism, the plating layer 102 itself can become an effective component of the magnetic circuit, rather than a magnetic resistance barrier. Furthermore, the first component, nickel, has good corrosion resistance, while the second components, iron and cobalt, have similar molar mass and density to nickel, thus allowing them to form an infinite solid solution, ensuring the density and compositional uniformity of the coating 102 structure. Adding cobalt to the coating 102 can improve its magnetism, hardness, and corrosion resistance; adding iron can improve its magnetism and reduce costs.

[0038] Understandably, in conventional techniques, amorphous materials are typically chosen for coating 102 to achieve higher permeability. While amorphous materials have higher initial permeability, they are prone to accumulating significant internal stress during fabrication. Furthermore, to maintain their amorphous state, amorphous materials usually contain large amounts of metalloid elements such as boron, silicon, and phosphorus, with ferromagnetic elements generally accounting for less than 80%. Consequently, the specific saturation magnetization of amorphous materials is typically low. This means that under conditions of extremely narrow magnetic gaps and extremely high magnetic flux density, such as in miniature loudspeakers, amorphous coating 102 is highly susceptible to magnetic saturation and failure. Moreover, the significant internal stress can lead to a decrease in the adhesion between coating 102 and the substrate, or even peeling, under conditions such as temperature shock. In contrast, this invention uses polycrystalline materials to prepare coating 102, resulting in a ferromagnetic material content of 90-100% in coating 102. A higher proportion of ferromagnetic material means more atomic magnetic moments in coating 102, stronger interatomic interactions, better magnetic permeability, and a higher specific saturation magnetization (≥5 emu / g). Meanwhile, the polycrystalline structure has perfect crystallization and good stability, avoiding the problem of amorphous materials continuously crystallizing as the temperature rises, which would result in poor stability of magnetic permeability.

[0039] Optionally, the mass percentage of ferromagnetic material in the coating 102 is 90-100%; for example, the mass percentage of ferromagnetic material in the coating 102 may be 90%, 92%, 94%, 95%, 96%, 98%, or 100%. Ferromagnetic materials (such as nickel, cobalt, and iron) are the main source of atomic magnetic moments. The higher the proportion, the more atoms participate in the formation and arrangement of magnetic domains per unit volume of the coating 102, and the stronger the exchange coupling between atoms. This allows the coating 102 to carry a higher magnetic flux density, exhibiting a higher specific saturation magnetization and superior magnetic permeability. Conversely, if the proportion of ferromagnetic material is too low, non-magnetic impurity elements (such as phosphorus, boron, and silicon) in the coating 102 will dilute the magnetic atom concentration, causing disordered magnetic domain arrangement and mutual cancellation of magnetic moments, weakening the overall magnetic permeability. Therefore, in this embodiment of the invention, the mass percentage of ferromagnetic material in the coating 102 is set to 90-100%. Furthermore, the key to achieving a 90-100% ferromagnetic material content in the embodiments of the present invention lies in the adoption of a polycrystalline structure, in which atoms are arranged in a regular manner, without relying on non-magnetic elements to maintain structural stability, thereby allowing the coating 102 to be mainly composed of high-purity ferromagnetic material.

[0040] Optionally, the specific saturation magnetization of the coating 102 is greater than or equal to 5 emu / g; for example, the specific saturation magnetization of the coating 102 is greater than or equal to 5 emu / g, 10 emu / g, 15 emu / g, 20 emu / g, 25 emu / g, 30 emu / g, 35 emu / g, 50 emu / g, 100 emu / g, 150 emu / g, 200 emu / g, etc.

[0041] Optionally, the specific saturation magnetization of coating 102 is less than or equal to 200 emu / g.

[0042] In this embodiment, the plating 102 in the magnetic conductive plate assembly 100 is a polycrystalline material, characterized by perfect crystallization, regular atomic arrangement, and high atomic packing density. Compared to amorphous materials, which typically require the addition of large amounts of non-magnetic elements such as boron, silicon, and phosphorus to maintain their amorphous state, resulting in a lower ferromagnetic material content, the polycrystalline material used in this embodiment can accommodate a higher proportion of ferromagnetic material. Therefore, the mass percentage of ferromagnetic material in the plating 102 can reach 90-100%. The higher the proportion of ferromagnetic material, the more atomic magnetic moments are contained in the plating 102, the stronger the exchange coupling between atoms, and the better the magnetic conductivity. Simultaneously, the perfect crystallization and good structural stability of the polycrystalline material effectively avoid the fluctuations in magnetic conductivity caused by the continuous crystallization transformation of amorphous materials during use or temperature rise, thereby ensuring the long-term consistency of the magnetic properties of the plating 102 within the actual operating temperature range of the speaker. Furthermore, the ferromagnetic material in the plating 102 includes at least nickel (i.e., the first component material) and at least one of iron and cobalt (i.e., the second component material). In this invention, iron, cobalt, and nickel atoms possess numerous unpaired electrons in their 3d electron shells, endowing each atom with a strong atomic magnetic moment. When the electron clouds of adjacent atoms overlap, strong exchange coupling occurs, causing the spin directions of unpaired electrons to tend towards parallelism. This spontaneously forms neatly arranged magnetic domains within a microscopic region. Under the influence of an external magnetic field, these domains align in an oriented manner, thus exhibiting strong macroscopic magnetism. Through this ferromagnetic mechanism, the coating 102 itself can become an effective component of the magnetic circuit, rather than a magnetoresistance barrier. Simultaneously, nickel possesses excellent corrosion resistance, providing a fundamental anti-corrosion capability for the coating 102. Iron and cobalt have similar molar masses and densities to nickel, allowing them to form an infinite solid solution, ensuring the compactness and compositional uniformity of the coating 102 structure. In this embodiment, the specific saturation magnetization of the coating 102 is not less than 5 emu / g, giving it effective anti-magnetic saturation capability. This enables stable magnetic conduction under the narrow magnetic gap and high magnetic flux density conditions of ultra-thin loudspeakers, reducing magnetic flux loss and achieving synergistic optimization of magnetic conductivity and corrosion resistance.

[0043] In one feasible embodiment, the specific saturation magnetization of the coating 102 is 20~200 emu / g. Specific saturation magnetization refers to 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 -10000~10000 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 crystal structure and composition of the material, making preparation more difficult. The embodiments of the present invention achieve high specific saturation magnetization precisely through the selection of the material for the coating 102.

[0044] In one feasible embodiment, if the second component material is cobalt, the mass percentage of the second component material in the ferromagnetic material is 3% to 50%. For example, the mass percentage of the second component material in the ferromagnetic material is 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0045] In this embodiment, the first component material is nickel, which accounts for more than or equal to 50% of the mass of the coating 102. This allows nickel to spontaneously form an extremely dense and stable passivation film on the surface of the coating 102. This film is very dense and can effectively block the intrusion of oxygen, water molecules, and various corrosive ions, improving the corrosion resistance of the coating 102. However, if the nickel content is too low, the corrosion resistance of the coating 102 deteriorates. When the second component material is cobalt, if the cobalt content is too low, the properties of the coating 102 are close to those of pure nickel, resulting in a low specific saturation magnetization and limited magnetic permeability, making it difficult to provide sufficient magnetic permeability under the high magnetic flux density conditions of ultra-thin magnetic circuits. If the cobalt content is too high, the coating 102 will exhibit permanent magnetism, with mutual attraction, making it difficult to uniformly disperse the coating 102 during the preparation process. Therefore, in this embodiment of the invention, if the second component material is cobalt, the mass percentage of the second component material in the ferromagnetic material is 3-50%. In this way, the coating 102 has both the high magnetic permeability of nickel and the high specific saturation magnetization of cobalt, and can also maintain good corrosion resistance.

[0046] In one feasible embodiment, if the second component material is iron, the mass percentage of the second component material in the ferromagnetic material is 3% to 40%. For example, the mass percentage of the second component material in the ferromagnetic material is 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc.

[0047] In this embodiment, when the second component material is iron, although iron atoms have a high atomic magnetic moment, their corrosion resistance is poor. Therefore, when the iron content in the coating 102 is higher than 40%, the corrosion resistance of the coating 102 will decrease rapidly. If the iron content is too low, the properties of the coating 102 are close to those of pure nickel, resulting in a low specific saturation magnetization and limited magnetic permeability, making it difficult to provide sufficient magnetic permeability under the high magnetic flux density conditions of ultra-thin magnetic circuits. Therefore, this embodiment of the invention determines that if the second component material is iron, the mass percentage of the second component material in the ferromagnetic material is 3-40%, thereby achieving an optimal balance between the high magnetic permeability, low manufacturing cost, good density of the coating 102, and acceptable corrosion resistance.

[0048] In one feasible embodiment, if the second component material is cobalt and iron, then the mass percentage of the second component material in the ferromagnetic material is 5% to 50%, wherein the mass percentage of iron is less than or equal to 40%. For example, the mass percentage of the second component material in the ferromagnetic material is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.; and the mass percentage of iron is less than or equal to 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 3%, etc.

[0049] In this embodiment, both iron and cobalt are elements with high saturation magnetization. Their addition significantly improves the specific saturation magnetization and permeability of the coating 102. Cobalt also improves the density of the oxide film, increases hardness, and enhances corrosion resistance, thus giving the coating 102 excellent overall performance. If the content of the second component is too low, the properties of the coating 102 will be close to pure nickel, resulting in a low specific saturation magnetization and limited permeability, making it difficult to provide sufficient magnetic permeability under the high flux density conditions of ultra-thin magnetic circuits. If the content of the second component is too high, the two elements will be difficult to disperse uniformly in the coating 102, leading to insufficient stability of the coating 102. Furthermore, this embodiment of the invention limits the mass percentage of iron to less than or equal to 40%. This is because although iron has extremely high specific saturation magnetization and low cost, its electrodeposition internal stress is high and its corrosion resistance is poor. If the iron content is too high, the corrosion resistance of the coating 102 will significantly decrease. Therefore, in this embodiment of the invention, if the second component material is cobalt and iron, the mass percentage of the second component material in the ferromagnetic material is 5-50%, wherein the mass percentage of iron is less than or equal to 40%, so that the coating 102 can simultaneously obtain high magnetic permeability, high saturation magnetic induction intensity, good corrosion resistance, moderate hardness and excellent coating 102 density.

[0050] In one feasible embodiment, the average corrosion rate of coating 102 in 5% NaCl solution is 0.01~20 mg / m. 2 For example, the average corrosion rate of coating 102 in 5% NaCl solution is 0.01 mg / m. 2 ·h, 0.05 mg / m 2 ·h, 0.1 mg / m 2 ·h, 0.5 mg / m 2 ·h, 1 mg / m 2 ·h, 2 mg / m 2 ·h, 5 mg / m 2 ·h, 10 mg / m 2 ·h, 15 mg / m 2 ·h, 20 mg / m2 ·h etc.

[0051] In this embodiment, the corrosion resistance test of the coating 102 can be evaluated by referring to the full immersion corrosion test. First, the magnetic plate assembly 100 is weighed and recorded as W0. Then, the magnetic plate assembly 100 is placed in a 5% NaCl solution for 96 hours. After removal, the surface corrosion is removed by ultrasonic cleaning. The magnetic plate assembly 100 is then thoroughly dried and weighed again, recorded as W1. The corrosion rate is calculated using the following formula: v = (W1 - W0) / (S × t), where S is the surface area of ​​the magnetic plate assembly 100 and t is the corrosion time. The average corrosion rate of the coating 102 in the 5% NaCl solution is determined to be 0.01~20 mg / m². 2 •h indicates good corrosion resistance.

[0052] 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.

[0053] In one feasible embodiment, the average thickness of the coating 102 is 1 to 50 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, 45 μm, 50 μm, etc.

[0054] Optionally, the average thickness of the coating 102 is 3~30 μm.

[0055] 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, reduces the corrosion resistance of the coating 102, and may even lead to the coating 102 peeling off. Therefore, in this embodiment of the invention, the average thickness of the coating 102 is determined to be less than or equal to 20% of the thickness of the body portion 101; the average thickness of the coating 102 is 1~50 μm.

[0056] In one feasible embodiment, the bonding force between the plating layer 102 and the body portion 101 is 4~5 B.

[0057] In this embodiment, the bonding force between the plating layer 102 and the body portion 101 can be tested using the cross-cut test. 4B requires slight peeling at the intersection of the cross-cuts, with a peeling area of ​​less than 5%, and 5B requires complete cut edges without peeling. The plating layer 102 and the body portion 101 in this embodiment of the invention exhibit good bonding force.

[0058] In one feasible embodiment, the roughness of the coating 102 is 0.01~1 μm; for example, the roughness of the coating 102 is 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, etc.

[0059] Optionally, the roughness of the coating 102 is 0.05~0.5 μm.

[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 0.01~1 μm.

[0061] In one feasible embodiment, the water contact angle of the coating 102 is 30° to 140°; for example, the water contact angle of the coating 102 is 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, etc.

[0062] Optionally, the water contact angle of the coating 102 is 50° to 120°.

[0063] In this embodiment, the smaller the water contact angle of the coating 102, the easier it is for liquids such as adhesives to spread on the surface of the coating 102, resulting in greater adhesion work and better bonding strength. However, if the water contact angle is too small, the surface of the coating 102 will easily absorb moisture, oil, and other dust, reducing its corrosion resistance. Therefore, this embodiment of the invention determines the water contact angle of the coating 102 to be 50°~120°, thereby ensuring the corrosion resistance of the coating 102 while maintaining good adhesion.

[0064] In one feasible embodiment, the coating 102 is passivated, and the passivation treatment includes at least one of chromate passivation, molybdate passivation, tungstate passivation, titanate passivation, silicate passivation, phytic acid passivation and tannic acid passivation.

[0065] In this embodiment, the plating layer 102 of the magnetic plate assembly 100 is passivated, thereby forming a dense passivation film (i.e., a protective film) on the surface of the plating layer 102, changing the wettability of the plating layer 102 surface and improving adhesion. Simultaneously, the passivation film prevents the main body 101 from contacting corrosive substances such as water and oxygen from the outside environment, hindering Cl... - The transfer of O2 between the metal coating 102 and the external medium, and the space charge layer formed on the passivation film surface have a repulsive effect on chloride ions, hindering the transfer of Cl. - It penetrates the passivation film to reach the body 101, further delaying the occurrence of pitting corrosion and improving corrosion resistance.

[0066] In one feasible embodiment, the coating 102 is subjected to a sealing treatment, and the sealing agent used in the sealing treatment includes at least one of water-based sealing agents, oil-based sealing agents, and nanocomposite sealing agents.

[0067] Optionally, the water-based sealant includes at least one of silicone sealants, polyurethane sealants, acrylate sealants, and epoxy resin sealants, which can form a transparent and dense organic polymer film on the surface of the coating 102 to isolate air and moisture.

[0068] Optionally, the oily sealant includes at least one of mineral oil and synthetic oil, which utilizes the hydrophobicity of the oil to form an oil film on the surface of the coating 102, isolating it from air and moisture.

[0069] Optionally, the nanocomposite sealant includes a polymer containing nanoparticles such as nano-silica and nano-alumina, which relies on the nanoparticles to fill the micropores on the surface of the coating 102, thereby improving the density and corrosion resistance of the coating.

[0070] In this embodiment, the surface of the coating 102 has microscopic pores, through which water, oxygen, chloride ions, etc., can directly reach the surface of the body 101, causing corrosion of the body 101. However, this embodiment of the invention, through a sealing treatment, can fill these pores on the surface of the coating 102, cutting off the invasion path of corrosive media and improving corrosion resistance. Simultaneously, the sealing agent used in the sealing treatment has a strong affinity for the coating 102, is not easily peeled off, and can also be used as a primer for subsequent bonding, enhancing the adhesion between the adhesive and the coating 102.

[0071] In one feasible embodiment, the saturation magnetic moment of the magnetic plate assembly 100 is 1 to 50% higher than that of the body portion 101 without a coating; for example, the saturation magnetic moment of the magnetic plate assembly 100 is 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc., higher than that of the body portion 101.

[0072] Optionally, the saturation magnetic moment can be measured using a vibrating sample magnetometer, wherein the test magnetic field range is -10000~10000 Oe.

[0073] Optionally, embodiments of the present invention can achieve excellent magnetic permeability by adjusting the content of ferromagnetic material in the coating 102; improve the corrosion resistance of the coating 102 by adjusting the content of nickel in the coating 102; and achieve excellent corrosion resistance by performing passivation and sealing treatments on the coating 102. Reliable adhesion can be obtained by adjusting the surface roughness and contact angle of the coating 102.

[0074] In this embodiment, the magnetic permeability of the magnetic plate assembly 100 is mainly related to the total amount of magnetic moment it contains. The higher the magnetic moment, the stronger the magnetic permeability. In this embodiment of the invention, by providing a plating layer 102 made of ferromagnetic material (i.e. containing nickel, iron and / or cobalt elements) on the surface of the body portion 101, the magnetic moment can be effectively provided, thereby making the saturation magnetic moment of the magnetic plate assembly 100 1 to 50% higher than that of the body portion 101 without the plating layer 102.

[0075] 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.

[0076] 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.

[0077] 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 coating 102 as described above, thereby achieving synergistic optimization of magnetic conductivity and corrosion resistance.

[0078] 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.

[0079] This invention also provides an electronic device, including the magnetic plate assembly or sound-generating device described above.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] Example 1 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is an electroplated nickel-cobalt alloy coating applied to the surface of the body. By mass percentage, the coating contains 58% nickel, 40% cobalt, and 2% unavoidable impurities. The surface of the coating is sealed with a water-based epoxy sealant.

[0084] Example 2 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is an electroplated nickel-cobalt alloy coating applied to the surface of the body. By mass percentage, the coating contains 90% nickel, 8% cobalt, and 2% unavoidable impurities. The surface of the coating is sealed with a water-based epoxy sealant.

[0085] Example 3 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is an electroplated nickel-cobalt-iron alloy coating applied to the surface of the body. By mass percentage, the coating contains 60% nickel, 28% cobalt, 10% iron, and 2% unavoidable impurities. The surface of the coating is sealed with a water-based epoxy sealant.

[0086] Example 4 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is an electroplated nickel-iron alloy coating applied to the surface of the body. By mass percentage, the coating contains 95% nickel, 4% iron, and 1% unavoidable impurities. The surface of the coating is sealed with a water-based epoxy sealant.

[0087] Example 5 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is an electroplated nickel-iron alloy coating applied to the surface of the body. By mass percentage, the coating contains 60% nickel, 39% iron, and 1% unavoidable impurities. The surface of the coating is sealed with a water-based epoxy sealant.

[0088] Comparative Example 1 A magnetic conductive plate is provided, comprising: The main body is made of SPCC substrate; The coating is a chemical high-phosphorus nickel coating applied to the surface of the body, with a phosphorus content of 10% by mass.

[0089] The magnetic plates of Examples 1-5 and Comparative Example 1 were tested, and the results are shown in Table 1 below: Table 1

[0090] Based on the test results above, the coating thickness of Examples 1-5 and Comparative Example 1 is 5 μm. Examples 1-5, however, are prepared by electroplating, which relies on metallic bonding and physical interlocking, resulting in higher adhesion. In contrast, the electroless nickel plating in Comparative Example 1, due to the formation of a dense phosphating film on the surface, has a lower average corrosion rate. Furthermore, it results in a smaller surface roughness and a larger contact angle, which is unfavorable for adhesion.

[0091] Furthermore, all examples in Example 1 were treated with a water-based epoxy sealant, thus forming an epoxy film on the surface. The corrosion resistance was similar to that of Comparative Example 1. At the same time, the epoxy sealant acted as a primer, introducing polar groups. Therefore, Examples 1-5 all had low contact angles, which facilitated adhesion. Due to the addition of iron, the corrosion rate of Examples 3-5 increased slightly, but it still met the usage requirements.

[0092] Furthermore, the coating in Example 1 has the highest cobalt content, thus exhibiting the highest specific saturation magnetization. In Example 3, due to the synergistic effect of iron and cobalt, its specific saturation magnetization is also at a relatively high level. In Example 5, the iron content is high, resulting in a high specific saturation magnetization. While the specific saturation magnetizations of Examples 2 and 4 are slightly lower, they are still significantly higher than those of Comparative Example 1. This is mainly because Comparative Example 1 is a high-phosphorus nickel coating, which has an amorphous structure, and phosphorus is a non-ferromagnetic material, thus resulting in a lower specific saturation magnetization.

[0093] Furthermore, the saturation magnetic moments of Example 2 and Comparative Example 1 were tested using a vibrating sample magnetometer, and the results are as follows: Figure 3 As shown, where, Figure 4 The horizontal axis represents the applied magnetic field strength, and the vertical axis represents the saturation magnetic moment. It can be seen that the saturation magnetic moment of Example 2 is 4.08 emu, while that of Comparative Example 1 is 3.27 emu. Example 2 shows an increase of approximately 25% in its saturation magnetic moment compared to Comparative Example 1. Currently, the maximum magnetic field strength of a miniature loudspeaker is approximately 15~25 A / m. Figure 3 It can be seen that within this range, the saturation magnetic moment of Example 2 is significantly higher than that of Comparative Example 1. Therefore, Example 2 can gather more magnetic field lines and has better magnetic permeability.

[0094] Furthermore, the magnetic plates from Example 2 and Comparative Example 1 were assembled into the same loudspeaker, and their mid-frequency acoustic performance was tested. The results are as follows: Figure 4 As shown, where, Figure 4 The horizontal axis represents frequency (in Hz), and the vertical axis represents sound pressure level (in dB). It can be seen that Example 2 has a higher magnetic permeability and magnetic focusing ability, so its mid-frequency sensitivity of 3~6 kHz is 0.3 dB higher than that of Comparative Example 1, thus exhibiting better sound reproduction.

[0095] 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.

[0096] 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 portion and a plating layer disposed on the surface of the body portion. The plating layer includes a ferromagnetic material, which is a polycrystalline material. The ferromagnetic material includes at least a first component material and a second component material. The first component material is nickel, and the second component material is at least one of iron and cobalt. The mass percentage of the ferromagnetic material in the plating layer is 90-100%, and the specific saturation magnetization of the plating layer is greater than or equal to 5 emu / g.

2. The magnetic conductive plate assembly as described in claim 1, characterized in that, If the second component is cobalt, then the mass percentage of the second component in the ferromagnetic material is 3-50%.

3. The magnetic conductive plate assembly as described in claim 1, characterized in that, If the second component material is iron, then the mass percentage of the second component material in the ferromagnetic material is 3-40%.

4. The magnetic conductive plate assembly as claimed in claim 1, characterized in that, If the second constituent material is cobalt and iron, then the mass percentage of the second constituent material in the ferromagnetic material is 5-50%, wherein the mass percentage of iron is less than or equal to 40%.

5. The magnetic conductive plate assembly as claimed in claim 1, characterized in that, The average corrosion rate of the coating in 5% NaCl solution is 0.01~20 mg / m. 2 ·h; And / or, 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 1~50 μm.

6. The magnetic plate assembly as claimed in claim 1, characterized in that, The bonding force between the coating and the body is 4~5 B; And / or, the roughness of the coating is 0.01~1 μm; And / or, the water contact angle of the coating is 30°~140°.

7. The magnetic plate assembly as described in any one of claims 1 to 6, characterized in that, The coating is passivated, and the passivation treatment includes at least one of the following: chromate passivation, molybdate passivation, tungstate passivation, titanate passivation, silicate passivation, phytic acid passivation, and tannic acid passivation. And / or, the coating is subjected to a sealing treatment, wherein the sealing agent used in the sealing treatment includes at least one of water-based sealing agents, oil-based sealing agents, and nanocomposite sealing agents.

8. The magnetic plate assembly as described in any one of claims 1 to 6, characterized in that, The saturation magnetic moment of the magnetic conductive plate assembly is 1 to 50% higher than that of the main body.

9. 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 8. 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.

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

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