Ultrathin device, manufacturing method therefor and use thereof

Abstract

An ultrathin device, a manufacturing method therefor and the use thereof. The manufacturing method for the ultrathin device comprises the following steps: by means of spray drying, granulating a mixture containing raw material powder, a binder and a solvent, so as to obtain a first precursor, wherein the raw material powder comprises metal material powder and / or ceramic material powder, the Sauter mean diameter of the raw material powder is 1 μm-15 μm, the mass ratio of the raw material powder to the binder is 100:(1-10), the Sauter mean diameter of the first precursor is 40 μm-80 μm, and the fluidity of the first precursor is less than 30s / 50g; performing forming treatment on the first precursor, so as to obtain a second precursor, the second precursor having a predefined shape; and performing thermal treatment on the second precursor, so as to obtain an ultrathin device, the thickness of the ultrathin device being less than or equal to 1 mm.

Description

Ultrathin device and its preparation method and application Technical Field

[0001] The present application relates to the technical field of powder metallurgy, and in particular to an ultra-thin device and a preparation method and application thereof. Background Art

[0002] For devices of specific shapes, they are usually prepared by stamping. Stamping uses a press and a die to apply external force to plates, strips, tubes, and profiles, causing them to undergo plastic deformation or separation, thereby obtaining workpieces of the desired shape and size. Stamping has high productivity, simple operation, is suitable for mass production, and has high dimensional accuracy.

[0003] For ultra-thin devices with small dimensions and thickness, especially those less than 1mm thick, stamping is subject to certain limitations. This is primarily due to the material limitations of stamping, which is primarily applicable to materials such as low-carbon steel and stainless steel, typically with a carbon content of less than 0.25% and a tensile strength of less than 650N / mm². However, some materials with low ductility and high hardness cannot be produced using stamping. Furthermore, stamping imposes certain restrictions on the shape of ultra-thin devices, resulting in a limited degree of freedom in manufacturing and an inability to meet demand. Technical issues

[0004] Some materials with low ductility and high hardness cannot be prepared through the stamping process. Moreover, the stamping process has certain limitations on the shape of ultra-thin devices, which makes the degree of freedom in manufacturing ultra-thin devices low and cannot meet the needs. Technical Solutions

[0005] In view of this, the present application proposes an ultra-thin device and its preparation method and application. The preparation method of the present application can prepare ultra-thin devices with small thickness and high shape freedom, which can fill the gap in the application of powder metallurgy technology in the field of ultra-thin devices and meet the needs of miniaturization and lightweight device products.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing an ultrathin device, comprising the following steps:

[0007] Granulating a mixture containing raw material powder, a binder, and a solvent by spray drying to obtain a first precursor, wherein the raw material powder includes metal material powder and / or ceramic material powder, the surface area average particle size of the raw material powder is 1 μm to 15 μm, the mass ratio of the raw material powder to the binder is 100:(1-10), the surface area average particle size of the first precursor is 40 μm to 80 μm, and the flowability of the first precursor is less than 30 s / 50 g;

[0008] Performing a molding process on the first precursor to obtain a second precursor, wherein the second precursor has a preset shape;

[0009] The second precursor is heat-treated to obtain the ultra-thin device, and the thickness of the ultra-thin device is less than or equal to 1 mm.

[0010] In some embodiments, the metal material in the metal material powder includes at least one of a single metal and an alloy.

[0011] In some embodiments, the metal element includes at least one of iron, cobalt, nickel, chromium, and manganese;

[0012] In some embodiments, the alloy includes at least one of an iron alloy, a copper alloy, a nickel alloy, a cobalt alloy, an aluminum alloy, and a titanium alloy.

[0013] In some embodiments, the ceramic material powder includes at least one of aluminum oxide powder, silicon oxide powder, zirconium oxide powder, silicon carbide powder, aluminum nitride powder, and silicon nitride powder.

[0014] In some embodiments, the particle size of the raw material powder satisfies: D90 / D10≤7.

[0015] In some embodiments, the adhesive comprises a thermoplastic adhesive comprising at least one of polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene glycol.

[0016] In some embodiments, the solvent includes at least one of water and ethanol.

[0017] In some embodiments, the sphericity of the first precursor is greater than or equal to 0.7.

[0018] In some embodiments, the air inlet temperature of the spray drying is 50°C to 300°C, and the air outlet temperature of the spray drying is 90°C to 200°C.

[0019] In some embodiments, the spray drying apparatus comprises at least one of a spray dryer, a centrifugal spray dryer, and a multi-nozzle spray dryer.

[0020] In some embodiments, subjecting the first precursor to a molding process includes placing the first precursor in a molding mold of a preset shape and performing a pressurizing process.

[0021] In some embodiments, the pressurizing treatment device comprises a servo press, and the displacement accuracy of the pressurizing treatment device is 1 μm to 3 μm.

[0022] In some embodiments, the pressure of the pressurization treatment is 300 MPa to 1200 MPa, and the time of the pressurization treatment is 2 s to 20 s.

[0023] In some embodiments, the material of the forming mold includes steel, and the steel includes at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV and DC53.

[0024] In some embodiments, the heat treatment temperature is 1100° C. to 1500° C., the heat treatment time is 0.5 h to 5 h, the heat treatment heating rate is 1° C. / min to 15° C. / min, and the heat treatment is performed under vacuum conditions.

[0025] The vacuum degree of the vacuum condition is less than or equal to 10 -2 Pa.

[0026] In a second aspect, an embodiment of the present application provides an ultra-thin device prepared by the preparation method described in the first aspect, wherein the thickness of the ultra-thin device is less than or equal to 1 mm.

[0027] In a third aspect, an embodiment of the present application provides an application of an ultrathin device prepared by the preparation method described in the first aspect or the ultrathin device described in the second aspect in the preparation of motors, engines, speakers, receivers, sounders, microphones, micro vibration motors and headphones. Beneficial effects

[0028] In the present application, before the molding process, the mixture containing raw material powder, adhesive and solvent is granulated by spray drying, and the surface area average particle size of the raw material powder is 1μm~15μm. On the one hand, it can ensure that the material has good fluidity; on the other hand, the average particle size of the raw material powder is small, and its mixing and granulation with a specific mass of adhesive is conducive to improving the density of the material and obtaining small-sized material. Compared with the traditional method of directly molding the raw material powder, the first precursor of the present application has excellent fluidity. The fluidity of the first precursor is lower than 30s / 50g, which is beneficial to the subsequent molding process, improves the fluidity of the material in the molding process, and is beneficial to improving the density and strength of the ultra-thin device after the molding process. Moreover, the first precursor of the present application with an average surface area particle size of 40μm~80μm has a small particle size, which is beneficial to improving the surface activity of the raw material powder. The powder in the material after granulation is tightly combined and has a good tap density. After molding and heat treatment, it can improve the molding performance of the molding process and improve the sintering performance of the heat treatment, reduce the sintering temperature, and improve the density and strength of the ultra-thin device after sintering. The first precursor before molding of the present application has good fluidity and a smaller particle size. In the preparation process, the thickness of the ultra-thin device can be reduced without having a significant impact on the mechanical properties such as strength, rigidity, and toughness of the ultra-thin device, thereby helping to improve the precision and miniaturization of the ultra-thin device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] FIG1 is a flow chart of a method for preparing an ultrathin device according to an embodiment of the present application;

[0031] FIG2 is a schematic structural diagram of the product of Example 1 provided in the embodiments of the present application;

[0032] FIG3 is a product size measurement result of Example 1 provided in the embodiments of the present application;

[0033] FIG4 is a schematic structural diagram of the product of Example 2 provided in the embodiments of the present application;

[0034] FIG5 is a product size measurement result of Example 2 provided in the examples of this application. Best Mode for Carrying Out the Invention

[0035] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0038] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0039] In the prior art, with the continuous development of molding technology, people have envisioned the preparation of devices with a high degree of freedom through simple preparation processes. At the same time, with the continuous development of technology, people have more and more demands for miniaturization and thinness of ultra-thin devices. There are mainly the following preparation methods for preparing ultra-thin devices with a high degree of freedom: 1. Stamping molding method, which mainly applies pressure through a press to produce plastic deformation or separation, thereby obtaining a workpiece of the required shape and size. 2. Powder metallurgy method, which mainly uses metal powder as raw material, and directly forms and sinters the powder raw material to manufacture metal materials, composite materials and various types of products. 3. Injection molding method, which is a plastic processing method that mainly forms a product by heating and plasticizing the material and then injecting it into the mold cavity of a closed mold by a plunger or a reciprocating screw. However, among the above-mentioned preparation methods, the stamping molding method cannot process materials with small thickness and poor ductility; the ultra-thin devices prepared by the powder metallurgy method have poor density, resulting in low strength of the ultra-thin devices, which cannot meet the demand. Ultra-thin devices prepared by injection molding have a high shrinkage rate, resulting in low product precision. Therefore, there is an urgent need for a preparation method for ultra-thin devices with high strength, good density and high precision to meet the needs of high strength, miniaturization and lightness of products.

[0040] In view of this, an embodiment of the present application provides a method for manufacturing an ultra-thin device, comprising the following steps:

[0041] Step S100: granulating a mixture containing raw material powder, a binder, and a solvent by spray drying to obtain a first precursor, wherein the surface area average particle size of the first precursor is 40 μm to 80 μm, and the fluidity of the first precursor is less than 30 s / 50 g. The raw material powder includes metal material powder and / or ceramic material powder, and the surface area average particle size of the raw material powder is 1 μm to 15 μm. The mass ratio of the raw material powder to the binder is 100:(1-10);

[0042] Step S200: forming the first precursor to obtain a second precursor having a preset shape;

[0043] Step S300: heat-treating the second precursor to obtain an ultra-thin device, wherein the thickness of the ultra-thin device is less than or equal to 1 mm.

[0044] In the above scheme, before the molding process, the present application granulates the mixture containing raw material powder, adhesive and solvent by spray drying, and the surface area average particle size of the raw material powder is 1μm~15μm. On the one hand, it can ensure that the material has good fluidity; on the other hand, the average particle size of the raw material powder is small, and it is mixed and granulated with a specific mass of adhesive, which is conducive to improving the density of the material and obtaining small-sized materials. Compared with the traditional method of directly molding the raw material powder, the first precursor of the present application has excellent fluidity. The fluidity of the first precursor is lower than 30s / 50g, which is beneficial to the subsequent molding process, improves the fluidity of the material in the molding process, and is beneficial to improving the density and strength of the ultra-thin device after the molding process. Moreover, the first precursor of the present application with an average surface area particle size of 40μm~80μm has a small particle size, which is beneficial to improving the surface activity of the raw material powder. The powder in the material after granulation is tightly combined and has a good tap density. After molding and heat treatment, it can improve the molding performance of the molding process and improve the sintering performance of the heat treatment, reduce the sintering temperature, and improve the density and strength of the ultra-thin device after sintering. The first precursor before molding of the present application has good fluidity and a smaller particle size. In the preparation process, the thickness of the ultra-thin device can be reduced without having a significant impact on the mechanical properties such as strength, rigidity, and toughness of the ultra-thin device, thereby helping to improve the precision and miniaturization of the ultra-thin device.

[0045] The following is a clear and complete description of the method for preparing an ultra-thin device in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0046] FIG1 is a flow chart of a method for preparing an ultrathin device according to an embodiment of the present application. As shown in FIG1 , the method for preparing the ultrathin device according to the present application includes the following steps:

[0047] Step S100: granulating a mixture containing raw material powder, a binder, and a solvent by spray drying to obtain a first precursor, wherein the raw material powder includes metal material powder and / or ceramic material powder, the surface area average particle size of the raw material powder is 1 μm~15 μm, the mass ratio of the raw material powder to the binder is 100:(1~10), the surface area average particle size of the first precursor is 40 μm~80 μm, and the fluidity of the first precursor is less than 30s / 50g.

[0048] Specifically, the first precursor is prepared by the following steps:

[0049] Step S101: Mix raw material powder, adhesive and solvent to obtain slurry, namely, mixed material.

[0050] In some embodiments, the raw material powder may be a metal material powder, a ceramic material powder, or a mixture of metal material powder and ceramic material powder, wherein: the metal material in the metal material powder includes at least one of a metal element and an alloy, and the metal element includes at least one of iron, cobalt, nickel, chromium, and manganese. The alloy includes at least one of an iron alloy, a copper alloy, a nickel alloy, a cobalt alloy, an aluminum alloy, and a titanium alloy. The ceramic material powder includes at least one of aluminum oxide powder, silicon oxide powder, zirconium oxide powder, silicon carbide powder, aluminum nitride powder, and silicon nitride powder. The above-mentioned raw material powders have low ductility and high hardness, and can meet the physical and chemical properties of the small-sized and ultra-thin devices of this application.

[0051] In some embodiments, the surface area average particle size of the raw material powder is 1 μm to 15 μm, for example, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, or 15 μm, and of course other values ​​within the above range are also possible, and this application is not limited thereto. The present application uses ultrafine raw material powder to manufacture components, which can make the components have excellent properties, such as high temperature resistance, high density, high strength, and high rigidity.

[0052] In some embodiments, the particle size of the raw material powder satisfies: D90 / D10≤7. Specifically, D90 / D10 can be 1, 2, 3, 4, 5, 6 or 7, etc., and of course it can also be other values ​​within the above range, which is not limited in this application. D90 is the particle size at which the cumulative distribution of raw material powder particles is 90%, and D10 is the particle size at which the cumulative distribution of raw material powder particles is 10%. Ideal molding processing raw materials need to have a narrow particle size distribution. Studies have shown that excessively fine powders have small particles and large surface energy, and particles tend to automatically aggregate to form larger particles to reduce surface energy. However, larger particles have lower fluidity and are prone to uneven distribution during the molding process, resulting in uneven stress distribution in the molded ultra-thin device. Therefore, by narrowing the particle size distribution, the mechanical properties of the ultra-thin device can be improved. The particle size of the raw material powder of the present application satisfies: D90 / D10≤7, indicating that the particle size span of the raw material powder is small, that is, the raw material powder has a relatively uniform particle size distribution, so that the raw material powder can avoid the above-mentioned problems while further having a higher bulk density, which is convenient for improving the density and precision of ultra-thin devices prepared by the raw material powder.

[0053] The raw material powder of the present application can be directly purchased from commercial sources, or raw materials with larger particle sizes can be prepared by mechanical grinding or other means to obtain raw material powder with composite particle size requirements.

[0054] In some embodiments, the adhesive comprises a thermoplastic adhesive, which includes vinyl polymers (polyvinyl acetate, polyvinyl alcohol, perchlorethylene, polyisobutylene, etc.), polyesters, polyethers, polyamides, polyacrylates, etc. Specifically, the thermoplastic adhesive may be at least one of polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene glycol. These adhesives exhibit high impact resistance, peel strength, and initial adhesion. They are easy to use, can bond well with the raw material powder, and are suitable for subsequent granulation processes.

[0055] In some embodiments, the mass ratio of the raw material powder to the binder is 100:(1-10), specifically 100:1, 100:2, 100:3, 100:5, 100:8, or 100:10, etc. Of course, other values ​​within the above range are also possible and are not limited herein. Within the above-defined range, the raw material powders in the mixture can be tightly connected and have suitable fluidity.

[0056] In some embodiments, the solvent includes water and an alcohol solvent. The alcohol solvent may be, for example, ethanol, propanol, pentanol, etc., which is not limited in this application.

[0057] Step S102: granulate the mixture by spray drying to obtain a first precursor.

[0058] This application utilizes a spray-drying method to atomize and granulate a slurry mixture with a certain solid content, thereby preventing reagglomeration or sedimentation of the components in the slurry. The slurry is uniformly atomized, resulting in spherical particles with uniform particle size distribution and good fluidity. The spherical particles have a small angle of repose, allowing the first precursor to flow freely during subsequent molding processes, which is beneficial for material molding and improves the uniformity of the first precursor's distribution during the preparation of ultra-thin devices.

[0059] In some embodiments, the spray drying equipment includes at least one of a spray dryer, a centrifugal spray dryer, and a multi-nozzle spray dryer. Preferably, the spray drying equipment is a centrifugal spray dryer.

[0060] In some embodiments, the inlet air temperature of the spray drying is 50°C to 300°C, and specifically can be 50°C, 80°C, 100°C, 200°C, 250°C, or 300°C, etc. Of course, it can also be other values ​​within the above range, and this application is not limited thereto. If the inlet air temperature is higher than 300°C, the liquid in the slurry is likely to evaporate excessively, and a large amount of heat remains after the liquid evaporates, which can easily cause the product to stick to the wall and be unable to be collected, or the product to deteriorate. If the inlet air temperature is less than 50°C, the product is in a semi-dry state, which can easily cause the product to stick together and form aggregates.

[0061] In some embodiments, the outlet air temperature of the spray drying device is 90°C to 200°C, and specifically, for example, it can be 90°C, 100°C, 130°C, 150°C, 170°C, 80°C, or 200°C. Of course, it can also be other values ​​within the above range, and this application is not limited thereto. Within the above-defined range, the semi-dried or dry material in the spray drying device can be heated, and the residual heat can be used to shape and dry the material, so that it reaches a completely dry state, avoids agglomeration of the material, and is conducive to the formation of spherical granular products.

[0062] In some embodiments, the sphericity of the first precursor is greater than or equal to 0.7, and can specifically be 0.7, 0.8, 0.9, and 1.0, etc., and can of course be other values ​​within the above range, without limitation. The first precursor prepared in the present application has a spherical shape. The spherical structure has good mixing uniformity and tight bonding performance, which can ensure the density and strength of the ultra-thin device.

[0063] In some embodiments, the surface area average particle size of the first precursor is 40μm to 80μm, specifically 40μm, 45μm, 50μm, 55μm, 60μm, 70μm or 80μm, etc. Within the above-defined range, it indicates that the particle size of the first precursor of the present application is small, that is, the raw material powder in the first precursor is tightly wrapped by the adhesive, and the density is high, which is conducive to the preparation of ultra-thin devices with small thickness and high strength; if the surface area average particle size of the first precursor is less than 40μm, it indicates that there is a lot of fine powder in the first precursor, which affects the strength and rigidity of the device; if the surface area average particle size of the first precursor is greater than 80μm, the material particles are large, the molding process is difficult, and the physical particles are prone to cracks or fragments during the molding process, resulting in poor molding effect. In this application, the surface area average particle size (SMD) refers to the average diameter of particles with the same volume to surface area ratio, which can be tested by a laser particle size tester and is used to characterize the particle size uniformity of a batch of material particles.

[0064] In some embodiments, the fluidity of the first precursor is lower than 30s / 50g, and can be specifically 5s / 50g, 10s / 50g, 15s / 50g, 20s / 50g, 25s / 50g or 30s / 50g, etc. It can be understood that the first precursor of the present application is a granular structure. Within the above-mentioned limited range, it shows that the first precursor has excellent fluidity, which enables the first precursor to be well filled into the mold of the molding process, which is beneficial to the stress uniformity of the material distribution during the subsequent molding process and improves the density of the green body after molding. At the same time, the smaller fluidity makes the material after the molding process have better smoothness and improves the precision of the ultra-thin device. In this application, fluidity refers to the time required for a certain amount of material particles to flow through a standard funnel with a specified aperture. The unit usually used is s / 50g. The smaller the value, the better the fluidity of the powder.

[0065] Step S200: forming the first precursor to obtain a second precursor having a preset shape.

[0066] In this step, the first precursor can be loaded into the hopper of the molding equipment and transported to the mold cavity with a preset shape through the feed pipe. The molded second precursor is obtained by applying pressure. The material utilization rate is high, which can significantly improve production efficiency and reduce preparation costs.

[0067] In some embodiments, the preset shape of the mold cavity is the shape of the final ultra-thin device, that is, the present application prepares a blank of the desired shape while applying pressure. During the pressurization process, the first precursors fully contact each other to form a blank, thereby improving the density and sealing effect of the blank, thereby improving the mechanical strength of the blank.

[0068] In some embodiments, the mold cavity is constructed from mold steel, including but not limited to at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV, and DC53, based on the shape and molding requirements of the ultra-thin device. These mold steels are capable of meeting the molding requirements of the second precursor and producing a green body with a predetermined shape and sufficient strength.

[0069] In some embodiments, the equipment for the forming process includes a servo press.

[0070] In some embodiments, the displacement accuracy of the molding processing equipment is 1 μm to 3 μm, for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm or 3 μm, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0071] In some embodiments, the pressure of the molding process is 300 MPa to 1200 MPa. Specifically, the pressure of the molding process can be 300 MPa, 500 MPa, 800 MPa, 1000 MPa, 1100 MPa, and 1200 MPa, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0072] In some embodiments, the molding process time is 2s~20s. Specifically, the molding process time is 2s, 5s, 8s, 10s, 13s, 15s, 18s or 20s, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0073] In some embodiments, the molding process may be a multi-stage pressure and time process combination, and the pressure and time used in each molding process combination may be any value within the aforementioned single-stage process range, which is not limited here.

[0074] Step S300: heat-treating the second precursor to obtain an ultra-thin device.

[0075] In this step, the second precursor obtained in step S200 is sintered by heat treatment so that it is solidified and has excellent mechanical properties.

[0076] In some embodiments, the heat treatment temperature is 1100°C to 1500°C, for example, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, or 1500°C. The present application may select different heat treatment temperature ranges based on different raw material powders, and is not limited to the above temperature range. During the heat treatment process, the second precursor generates supramolecular forces and interpenetrating effects to consolidate, thereby improving the strength, toughness, and density of the ultra-thin device.

[0077] In some embodiments, the heat treatment time is 0.5 h to 5 h, for example, 0.5 h, 1 h, 2 h, 3 h, 4 h or 5 h, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0078] In some embodiments, the heating rate of the heat treatment is 1°C / min to 15°C / min, for example, it can be 1°C / min, 3°C / min, 5°C / min, 8°C / min, 10°C / min, 13°C / min or 15°C / min, etc. Of course, it can also be other values ​​within the above range, which is not limited here.

[0079] In some embodiments, the heat treatment is performed under vacuum conditions to prevent oxygen from entering and oxidizing the second precursor, which would reduce the purity of the ultra-thin device and affect the quality of the ultra-thin device.

[0080] In some embodiments, the vacuum degree of the vacuum condition is less than or equal to 10 -2 Pa, for example, can be 10 -5 , 10 -4 , 10 -3 or 10 -2 Of course, it can also be other values ​​within the above range, which is not limited here.

[0081] In some embodiments, the heat treatment further includes a step of post-processing the material obtained by the heat treatment, such as grinding, polishing, and electroplating, to improve the physical and mechanical properties of the ultra-thin device.

[0082] The embodiments of the present application also provide an ultrathin device prepared by the above-mentioned manufacturing method. The ultrathin device has a specific shape, and the thickness of the ultrathin device is less than or equal to 1 mm, which can well fill the gap in the application field of ultrathin devices prepared by powder metallurgy.

[0083] The embodiments of the present application also provide the use of the above-mentioned ultra-thin devices in the preparation of motors, engines, speakers, receivers, sounders, microphones, micro vibration motors and headphones, which is beneficial to improving the precision and lightness of the above-mentioned devices.

[0084] The following further describes the embodiments of the present invention in multiple embodiments. The embodiments of the present invention are not limited to the following specific embodiments. Within the scope of the unchanged main rights, appropriate changes can be made to the implementation. Embodiment 1:

[0085] (1) Weigh 100 g of ferroalloy powder, 20 g of polyvinyl pyrrolidone and 3 g of water, mix and stir to obtain a mixed slurry, wherein the surface area average particle size of the ferroalloy powder is 1 to 5 μm, and the particle size of the ferroalloy powder satisfies: D90 / D10≤7.

[0086] (2) The mixed slurry of step (1) is dried by a centrifugal spray dryer at an air inlet temperature of 80°C and an air outlet temperature of 100°C to obtain a granular first precursor. The surface area average particle size of the first precursor is 40-80 μm and the fluidity is less than 30 s / 50 g.

[0087] (3) The first precursor of step (2) is loaded into the hopper of the servo press and transported to the mold cavity through the material pipe. The shape of the mold cavity is shown in Figure 2. The pressure is 300~1200MPa, the time is 2s~20s, and the accuracy is 2μm to obtain the second precursor.

[0088] (4) The second precursor of step (3) is sent to a vacuum sintering furnace for sintering at a temperature of 1200°C and a sintering time of 3 hours. After sintering, it is ground and polished to obtain an ultra-thin device. Example 2:

[0089] (1) Weigh 100 g of ferroalloy powder, 20 g of polyvinyl pyrrolidone and 3 g of water, mix and stir to obtain a mixed slurry, wherein the surface area average particle size of the ferroalloy powder is 1 to 5 μm, and the particle size of the ferroalloy powder satisfies: D90 / D10≤7.

[0090] (2) The mixed slurry of step (1) is dried by a centrifugal spray dryer at an air inlet temperature of 80°C and an air outlet temperature of 100°C to obtain a granular first precursor. The surface area average particle size of the first precursor is 40-80 μm and the fluidity is less than 30 s / 50 g.

[0091] (3) The first precursor of step (2) is loaded into the hopper of the servo press and transported to the mold cavity through the material pipe. The shape of the mold cavity is shown in Figure 4. The pressure is 300~1200MPa, the time is 2s~20s, and the accuracy is 2μm to obtain the second precursor.

[0092] (4) The second precursor of step (3) is sent to a vacuum sintering furnace for sintering at a temperature of 1200°C and a sintering time of 3 hours. After sintering, it is ground and polished to obtain an ultra-thin device.

[0093] According to the preparation process given in Example 1 of this application, specific process parameters were selected to prepare 20 different ultrathin devices. According to the preparation process given in Example 2, specific process parameters were selected to prepare 10 different ultrathin devices. The thickness, length, width, and flatness of the above 30 different ultrathin devices were measured. The thickness, length, and width were measured using a micrometer. The flatness was measured by placing the target ultrathin device on a precision flat workbench and fixing it. The measuring part of the micrometer was installed so that it could contact the measuring surface. The target ultrathin device was moved so that the measurement positions were evenly distributed. The indication of the micrometer was read. The maximum value of the measured deviation is the flatness.

[0094] As shown in Figure 3, it is the size measurement result of the ultra-thin device prepared in Example 1. It can be seen from Figure 3 that the thickness of the ultra-thin device in Example 1 of the present application is between 0.372mm and 0.386mm, the flatness is between 0 and 0.025mm, and the numerical distribution is relatively uniform, indicating that the preparation method of the present application can produce ultra-thin devices with high precision and ultra-thinness.

[0095] As shown in Figure 5, the size measurement results of the ultra-thin device prepared in Example 2 are shown. It can be seen from Figure 5 that two different parts in Figure 5 are selected for thickness measurement. The thickness of part 1 is between 0.450 mm and 0.485 mm, and the thickness of part 2 is between 0.150 mm and 0.180 mm, and the numerical distribution is relatively uniform, indicating that the preparation method of the present application can produce ultra-thin devices with high precision.

[0096] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

[0097] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the claims. Any person skilled in the art may make several possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A method for preparing an ultra-thin device, It is characterized in that The steps include: Granulating a mixture containing raw material powder, a binder and a solvent by spray drying to obtain a first precursor, wherein the raw material powder includes metal material powder and / or ceramic material powder, the surface area average particle size of the raw material powder is 1 μm to 15 μm, the mass ratio of the raw material powder to the binder is 100:(1 to 10), the surface area average particle size of the first precursor is 40 μm to 80 μm, and the fluidity of the first precursor is lower than 30 s / 50 g; Performing a molding process on the first precursor to obtain a second precursor, wherein the second precursor has a preset shape; The second precursor is heat-treated to obtain the ultra-thin device, and the thickness of the ultra-thin device is less than or equal to 1 mm.

2. The preparation method according to claim 1, It is characterized in that The metal material in the metal material powder includes at least one of a metal element and an alloy, the metal element includes at least one of iron, cobalt, nickel, chromium and manganese; the alloy includes at least one of an iron alloy, a copper alloy, a nickel alloy, a cobalt alloy, an aluminum alloy and a titanium alloy.

3. The preparation method according to claim 1, It is characterized in that The ceramic material powder includes at least one of aluminum oxide powder, silicon oxide powder, zirconium oxide powder, silicon carbide powder, aluminum nitride powder and silicon nitride powder.

4. The preparation method according to claim 1, It is characterized in that The particle size of the raw material powder satisfies: D90 / D10≤7.

5. The preparation method according to claim 1, It is characterized in that The adhesive comprises a thermoplastic adhesive, and the adhesive comprises at least one of polyvinyl alcohol, polyvinyl pyrrolidone and polyethylene glycol.

6. The preparation method according to claim 1, It is characterized in that The solvent includes at least one of water and ethanol.

7. The preparation method according to claim 1, It is characterized in that The sphericity of the first precursor is greater than or equal to 0.

7.

8. The preparation method according to claim 1, It is characterized in that The inlet air temperature of the spray drying is 50°C to 300°C, and the outlet air temperature of the spray drying is 90°C to 200°C.

9. The preparation method according to claim 1, It is characterized in that The spray drying equipment includes at least one of a spray dryer, a centrifugal spray dryer and a multi-nozzle spray dryer.

10. The preparation method according to claim 1, It is characterized in that The molding process of the first precursor includes: placing the first precursor in a molding mold of a preset shape and performing a pressurization process.

11. The preparation method according to claim 10, It is characterized in that The pressurizing treatment equipment includes a servo press, and the displacement accuracy of the servo press is 1 μm to 3 μm.

12. The preparation method according to claim 10, It is characterized in that The pressure of the pressurization treatment is 300 MPa to 1200 MPa, and the time of the pressurization treatment is 2s to 20s.

13. The preparation method according to claim 10, It is characterized in that The material of the forming die includes steel, and the steel includes at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV, and DC53.

14. According to the preparation method described in claim 1, it is characterized in that the heat treatment satisfies: the temperature of the heat treatment is 1100°C to 1500°C; the time of the heat treatment is 0.5 h to 5 h; the heating rate of the heat treatment is 1°C / min to 15°C / min; The heat treatment is carried out under vacuum conditions, and the degree of vacuum of the vacuum conditions is less than or equal to 10 -2 Pa.

15. An ultra-thin device prepared by the preparation method described in any one of claims 1 to 14, it is characterized in that the thickness of the ultra-thin device is less than or equal to 1 mm.

16. Application of an ultra-thin device prepared by the preparation method described in any one of claims 1 to 14 or the ultra-thin device described in claim 15 in the preparation of motors, engines, speakers, receivers, buzzers, microphones, micro vibration motors, and earphones.

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