An ultrathin device and a preparation method and application thereof

Abstract

The application relates to an ultrathin device and a preparation method and application thereof. The ultrathin device is prepared by the following steps: a mixture containing raw material powder, a binder and a solvent is granulated by a spray drying method to obtain a first precursor, the raw material powder comprises metal material powder and / or ceramic material powder, the surface area average particle size of the raw material powder is 1-15 mu m, 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 40-80 mu m, and the fluidity of the first precursor is lower than 30 s / 50 g; the first precursor is subjected to a forming treatment to obtain a second precursor, the second precursor has a preset shape; and the second precursor is subjected to a heat treatment to obtain the ultrathin device, and the thickness of the ultrathin device is less than or equal to 1 mm.

Description

Technical Field

[0001] This application relates to the field of powder metallurgy technology, and more specifically, to an ultrathin device, its preparation method, and its application. Background Technology

[0002] For devices of specific shapes, they are usually manufactured by stamping. Stamping uses a press and mold to apply external force to sheet metal, strip, tube and profile, causing plastic deformation or separation, thereby obtaining workpieces of the required shape and size. Stamping has high productivity, is easy to operate, is suitable for mass production, and has high dimensional accuracy.

[0003] For ultra-thin devices with small dimensions and thicknesses, especially those less than 1 mm thick, stamping methods are subject to certain limitations. This is primarily because stamping for ultra-thin devices is restricted by the types of materials used; it is mainly suitable for materials such as low-carbon steel and stainless steel, generally with a carbon content of <0.25% and a tensile strength of less than 650 N / mm². However, some materials with low ductility and high hardness cannot be manufactured using stamping. Furthermore, stamping imposes certain limitations on the shape of ultra-thin devices, resulting in limited manufacturing freedom and failing to meet specific requirements. Summary of the Invention

[0004] In view of this, this application proposes an ultrathin device, its preparation method and application. The preparation method of this application can produce ultrathin devices with small thickness and high degree of shape freedom, which can fill the gap in the application of powder metallurgy technology in the field of ultrathin devices and meet the needs of miniaturization and thinning of device products.

[0005] In a first aspect, embodiments of this application provide a method for fabricating an ultrathin device, comprising the following steps:

[0006] A mixture containing raw material powder, binder and solvent is granulated by spray drying to obtain a first precursor. The raw material powder includes metal material powder and / or ceramic material powder. The average surface area particle size of the raw material powder is 1μm to 15μm. The mass ratio of the raw material powder to the binder is 100:(1 to 10). The average surface area particle size of the first precursor is 40μm to 80μm. The flowability of the first precursor is less than 30s / 50g.

[0007] The first precursor is shaped to obtain a second precursor, which has a preset shape.

[0008] The second precursor is heat-treated to obtain the ultrathin device, the thickness of which is less than or equal to 1 mm.

[0009] In some embodiments, the metal material in the metal material powder includes at least one of elemental metals and alloys.

[0010] In some embodiments, the metallic element includes at least one selected from iron, cobalt, nickel, chromium, and manganese;

[0011] In some embodiments, the alloy includes at least one selected from iron alloys, copper alloys, nickel alloys, cobalt alloys, aluminum alloys, and titanium alloys.

[0012] In some embodiments, the ceramic material powder includes at least one of alumina powder, silicon oxide powder, zirconium oxide powder, silicon carbide powder, aluminum nitride powder, and silicon nitride powder.

[0013] In some embodiments, the particle size of the raw material powder satisfies: D90 / D10≤7.

[0014] In some embodiments, the adhesive includes a thermoplastic adhesive, which includes at least one of polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol.

[0015] In some embodiments, the solvent includes at least one of water and ethanol.

[0016] In some implementations, the sphericity of the first precursor is greater than or equal to 0.7.

[0017] In some embodiments, the inlet air temperature of the spray dryer is 50°C to 300°C, and the outlet air temperature of the spray dryer is 90°C to 200°C.

[0018] 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.

[0019] In some embodiments, molding the first precursor includes placing the first precursor in a molding die of a preset shape and applying pressure.

[0020] In some embodiments, the pressurization device includes a servo press, and the displacement accuracy of the pressurization device is 1 μm to 3 μm.

[0021] In some embodiments, the pressure of the pressurization process is 300 MPa to 1200 MPa, and the pressurization time is 2 s to 20 s.

[0022] In some embodiments, the molding die is made of steel, including at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV and DC53.

[0023] In some embodiments, the heat treatment temperature is 1100℃~1500℃, the heat treatment time is 0.5h~5h, the heat treatment heating rate is 1℃ / min~15℃ / min, and the heat treatment is carried out under vacuum conditions, wherein the vacuum degree is less than or equal to 10. -2 Pa.

[0024] Secondly, embodiments of this application provide an ultrathin device prepared by the preparation method described in the first aspect, wherein the thickness of the ultrathin device is less than or equal to 1 mm.

[0025] Thirdly, embodiments of this application provide an application of the 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, loudspeakers, receivers, buzzers, microphones, micro vibration motors, and headphones.

[0026] The technical solution of this application has at least the following beneficial effects:

[0027] Before molding, this application granulates a mixture containing raw material powder, binder and solvent by spray drying. The average particle size of the raw material powder is 1μm to 15μm. On the one hand, this ensures that the material has good flowability. On the other hand, the small average particle size of the raw material powder, when mixed with a specific amount of binder for granulation, helps to improve the density of the material and obtain small-sized material. Compared to traditional methods of directly molding raw material powder, the first precursor of this application exhibits excellent flowability, with a flowability of less than 30s / 50g. This is beneficial for subsequent molding processes, improving the material's flowability during molding and enhancing the density and strength of the ultra-thin devices after molding. Furthermore, the first precursor of this application has a small particle size with an average surface area particle size of 40μm to 80μm, which helps to enhance the surface activity of the raw material powder. The granulated material has tightly bound powder particles and good tap density. Subsequent molding and heat treatment can improve the molding performance of the molding process and the sintering performance of the heat treatment, reduce the sintering temperature, and increase the density and strength of the ultra-thin devices after sintering. The first precursor of this application has good flowability and a small particle size before molding. In the preparation process, the thickness of the ultra-thin devices can be reduced without significantly affecting the mechanical properties such as strength, rigidity, and toughness of the ultra-thin devices, thereby improving the precision and miniaturization of the ultra-thin devices. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the fabrication method of the ultrathin device provided in the embodiments of this application;

[0030] Figure 2 This is a structural schematic diagram of the product of Embodiment 1 provided in this application;

[0031] Figure 3 The product size measurement results of Embodiment 1 provided in this application;

[0032] Figure 4 This is a schematic diagram of the structure of the product of Embodiment 2 provided in this application.

[0033] Figure 5 The product size measurement results of Embodiment 2 provided in this application are as follows. Detailed Implementation

[0034] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0035] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0036] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0038] In existing technologies, with the continuous development of molding processes, people envision fabricating devices with high degrees of freedom through simple manufacturing processes. Simultaneously, with the continuous development of technology, the demand for miniaturization and thinning of ultra-thin devices is increasing. The following are the main manufacturing methods used to produce ultra-thin devices with high degrees of freedom: 1. Stamping: This method mainly uses a press to apply pressure, causing plastic deformation or separation to obtain workpieces of the desired shape and size. 2. Powder metallurgy: This method mainly uses metal powder as raw material, directly shaping and sintering the powder raw material to manufacture metal materials, composite materials, and various types of products. 3. Injection molding: This method mainly involves heating and plasticizing the material, then injecting it into the cavity of a closed mold using a plunger or reciprocating screw to form a product. However, among the above manufacturing methods, stamping cannot process materials with small thickness and poor ductility; ultra-thin devices prepared by powder metallurgy have poor density, resulting in low strength and failing to meet requirements. The high shrinkage rate of ultra-thin devices prepared by injection molding results in low product precision. Therefore, there is an urgent need for a method to prepare ultra-thin devices with high strength, good density, and high precision to meet the requirements of high strength, miniaturization, and thinness of products.

[0039] In view of this, embodiments of this application provide a method for fabricating an ultrathin device, comprising the following steps:

[0040] Step S100: The mixture containing raw material powder, binder and solvent is granulated by spray drying to obtain a first precursor. The average surface area particle size of the first precursor is 40μm to 80μm, and the flowability of the first precursor is less than 30s / 50g. The raw material powder includes metal material powder and / or ceramic material powder. The average surface area particle size of the raw material powder is 1μm to 15μm, and the mass ratio of raw material powder to binder is 100:(1 to 10).

[0041] Step S200: The first precursor is shaped to obtain the second precursor, which has a preset shape.

[0042] Step S300: Heat-treat the second precursor to obtain an ultra-thin device with a thickness of less than or equal to 1 mm.

[0043] In the above scheme, before the molding process, the mixture containing raw material powder, binder and solvent is granulated by spray drying. The average particle size of the raw material powder is 1μm to 15μm. On the one hand, this can ensure that the material has good flowability. On the other hand, the average particle size of the raw material powder is small. When mixed with a specific amount of binder for granulation, it is beneficial to improve the density of the material and obtain small-sized material. Compared to traditional methods of directly molding raw material powder, the first precursor of this application exhibits excellent flowability, with a flowability of less than 30s / 50g. This is beneficial for subsequent molding processes, improving the material's flowability during molding and enhancing the density and strength of the ultra-thin devices after molding. Furthermore, the first precursor of this application has a small particle size with an average surface area particle size of 40μm to 80μm, which helps to enhance the surface activity of the raw material powder. The granulated material has tightly bound powder particles and good tap density. Subsequent molding and heat treatment can improve the molding performance of the molding process and the sintering performance of the heat treatment, reduce the sintering temperature, and increase the density and strength of the ultra-thin devices after sintering. The first precursor of this application has good flowability and a small particle size before molding. In the preparation process, the thickness of the ultra-thin devices can be reduced without significantly affecting the mechanical properties such as strength, rigidity, and toughness of the ultra-thin devices, thereby improving the precision and miniaturization of the ultra-thin devices.

[0044] The fabrication method of ultrathin devices will now be clearly and completely described with reference to the accompanying drawings of the embodiments of the present invention. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0045] Figure 1 A fabrication flowchart of an ultrathin device provided in this application embodiment is shown below. Figure 1 As shown, the method for fabricating the ultrathin device of this application includes the following steps:

[0046] Step S100: The mixture containing raw material powder, binder and solvent is granulated by spray drying to obtain a first precursor. The raw material powder includes metal material powder and / or ceramic material powder. The average surface area particle size of the raw material powder is 1μm to 15μm. The mass ratio of raw material powder to binder is 100:(1 to 10). The average surface area particle size of the first precursor is 40μm to 80μm. The flowability of the first precursor is less than 30s / 50g.

[0047] Specifically, the preparation of the first precursor includes the following steps:

[0048] Step S101: Mix the raw material powder, binder and solvent to obtain a slurry, which is the mixture.

[0049] In some embodiments, the raw material powder can be a metal powder, a ceramic powder, or a mixture of metal and ceramic powders. Specifically: the metal powder includes at least one of elemental metals and alloys; the elemental metals include at least one of iron, cobalt, nickel, chromium, and manganese; the alloys include at least one of iron alloys, copper alloys, nickel alloys, cobalt alloys, aluminum alloys, and titanium alloys; and the ceramic powder includes at least one of alumina powder, silicon oxide powder, zirconium oxide powder, silicon carbide powder, aluminum nitride powder, and silicon nitride powder. The above-mentioned raw material powders have relatively low ductility and high hardness, which meets the physical and chemical performance requirements of the small-size, ultra-thin devices of this application.

[0050] In some embodiments, the average particle size of the raw material powder is 1 μm to 15 μm, for example, it can be 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm or 15 μm, etc., and of course, it can be other values ​​within the above range, which are not limited here. The use of ultrafine raw material powder in this application to manufacture parts enables the parts to have excellent properties, such as high temperature resistance, high density, high strength and high rigidity.

[0051] 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, or other values ​​within the above range, which are not limited herein. D90 is the particle size at which 90% of the raw material powder particles are cumulatively distributed, and D10 is the particle size at which 10% of the raw material powder particles are cumulatively distributed. Ideally, the raw material for molding requires a narrow particle size distribution. Studies have shown that excessively fine powder, due to its small particle size and high surface energy, tends to automatically aggregate to form larger particles, thereby reducing surface energy. Larger particles have lower flowability and are prone to uneven distribution during molding, leading to uneven stress distribution in the molded ultrathin devices. Therefore, by narrowing the particle size distribution, the mechanical properties of ultrathin devices can be improved. The particle size of the raw material powder in this application satisfies: D90 / D10≤7, which indicates that the particle size range of the raw material powder is small, that is, the raw material powder has a relatively uniform particle size distribution. This allows the raw material powder to avoid the above-mentioned problems, while also having a higher packing density, which is conducive to improving the density and precision of the raw material powder in the preparation of ultra-thin devices.

[0052] The raw material powder used in this application can be purchased directly from commercial sources, or raw materials with larger particle sizes can be prepared into raw material powder with the required particle size through mechanical grinding or other means.

[0053] In some embodiments, the adhesive includes a thermoplastic adhesive, which includes olefin polymers (polyvinyl acetate, polyvinyl alcohol, chlorinated polyethylene, polyisobutylene, etc.), polyesters, polyethers, polyamides, polyacrylates, etc. Specifically, the thermoplastic adhesive can be at least one of polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol. The above-mentioned adhesives have the characteristics of good impact resistance, peel strength, and initial tack, are easy to use, can bond well with raw material powders, and are suitable for subsequent granulation processes.

[0054] In some embodiments, the mass ratio of raw material powder to binder is 100:(1-10), specifically 100:1, 100:2, 100:3, 100:5, 100:8, or 100:10, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. Within the above-defined range, it is possible to ensure that the raw material powder in the mixture is tightly connected and has suitable flowability.

[0055] In some embodiments, the solvent includes water and alcohol solvents, such as ethanol, propanol, pentanol, etc., which are not limited herein.

[0056] Step S102: The mixture is granulated by spray drying to obtain the first precursor.

[0057] This application utilizes spray drying to atomize and granulate a slurry mixture with a certain solid content. This avoids re-agglomeration or sedimentation of the components in the slurry, while ensuring uniform atomization, resulting in spherical particles with uniform particle size distribution and good flowability. The spherical particles have a small angle of repose, allowing the first precursor to flow freely during subsequent molding processes. This is beneficial for material molding and improves the uniformity of material distribution during the fabrication of ultrathin devices.

[0058] 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.

[0059] In some embodiments, the inlet air temperature for spray drying is 50℃ to 300℃, specifically, for example, 50℃, 80℃, 100℃, 200℃, 250℃, or 300℃, and of course, other values ​​within the above range are also possible; this application does not impose any limitations on this. If the inlet air temperature is higher than 300℃, excessive evaporation of the liquid in the slurry is likely, and a large amount of heat remains after the liquid evaporates, which can easily cause the product to stick to the wall and become uncollectible or to deteriorate. If the inlet air temperature is lower than 50℃, the product is in a semi-dry state, which can easily cause the product to clump together and form aggregates.

[0060] In some embodiments, the outlet air temperature of the spray dryer is 90℃ to 200℃, specifically, for example, 90℃, 100℃, 130℃, 150℃, 170℃, 80℃, or 200℃, etc., and of course, other values ​​within the above range are also possible, which are not limited herein. Within the above-defined range, the material that has reached a semi-dry or dry state in the spray drying equipment can be heated, and the residual heat can be used to shape and dry the material, so that it reaches a completely dry state, avoiding the agglomeration of the material and facilitating the formation of spherical granular products.

[0061] In some embodiments, the sphericity of the first precursor is greater than or equal to 0.7, specifically 0.7, 0.8, 0.9, and 1.0, or other values ​​within the above range, which are not limited here. The first precursor prepared in this application has a near-spherical shape. The near-spherical structure has good mixing uniformity and tight bonding performance, which can ensure the density and strength of the fabricated ultrathin devices.

[0062] In some embodiments, the surface mean particle size of the first precursor is 40 μm to 80 μm, specifically 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 70 μm, or 80 μm. Within the above-mentioned range, it indicates that the particle size of the first precursor in this application is relatively small, that is, the raw material powder in the first precursor is tightly wrapped by the binder, resulting in high density, which is beneficial for preparing ultra-thin devices with small thickness and high strength. If the surface mean particle size of the first precursor is less than 40 μm, 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 mean particle size of the first precursor is greater than 80 μm, the material particles are large, making the molding process 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 mean diameter (SMD) refers to the average diameter of particles with the same volume and surface area ratio, which can be tested by a laser particle size analyzer and is used to characterize the particle size uniformity of a batch of material particles.

[0063] In some embodiments, the flowability of the first precursor is less than 30 s / 50 g, specifically 5 s / 50 g, 10 s / 50 g, 15 s / 50 g, 20 s / 50 g, 25 s / 50 g, or 30 s / 50 g, etc. It can be understood that the first precursor in this application has a granular structure. Within the above-mentioned limits, this indicates that the first precursor has excellent flowability, enabling it to fill the mold in the molding process well. This is beneficial for the uniformity of stress distribution in the material distribution during subsequent molding processes, improving the density of the molded blank. Simultaneously, the lower flowability results in better smoothness of the molded material, improving the precision of ultra-thin devices. In this application, flowability refers to the time required for a certain amount of material particles to flow through a standard funnel of a specified aperture. The commonly used unit is s / 50 g, and the smaller the value, the better the flowability of the powder.

[0064] Step S200: The first precursor is shaped to obtain the second precursor, which has a preset shape.

[0065] 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 conveying pipe. The molded second precursor is obtained by applying pressure. The material utilization rate is high, which can significantly improve the manufacturing efficiency and reduce the preparation cost.

[0066] In some embodiments, the preset shape of the mold cavity is the shape of the final fabricated ultra-thin device. That is, this application prepares a blank of the required shape while applying pressure. During the pressure process, the first precursors come into full contact with each other to form a blank, thereby improving the compactness and sealing effect of the blank and thus improving the mechanical strength of the blank.

[0067] In some embodiments, the mold cavity is made of mold steel selected according to the shape and forming requirements of the ultra-thin device. The mold steel includes, but is not limited to, at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV, and DC53. Mold steels of the above materials can ensure the forming requirements of the second precursor, producing a blank with a predetermined shape and a certain strength.

[0068] In some implementations, the equipment for the forming process includes a servo press.

[0069] In some embodiments, the displacement accuracy of the molding process equipment is 1μm to 3μm, for example, it can be 1μm, 1.5μm, 2μm, 2.5μm or 3μm, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0070] In some embodiments, the molding process pressure is 300MPa to 1200MPa. Specifically, the molding process pressure can be 300MPa, 500MPa, 800MPa, 1000MPa, 1100MPa and 1200MPa, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0071] In some embodiments, the molding process takes 2 to 20 seconds. Specifically, the molding process takes 2 seconds, 5 seconds, 8 seconds, 10 seconds, 13 seconds, 15 seconds, 18 seconds, or 20 seconds, etc. Of course, other values ​​within the above range are also possible and are not limited here.

[0072] In some implementations, the molding process can be a combination of multiple pressure and time processes. The pressure and time used in each molding process combination can be any value within the range of the aforementioned single process, and there is no limitation.

[0073] Step S300: Heat-treat the second precursor to obtain an ultra-thin device.

[0074] 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.

[0075] In some embodiments, the heat treatment temperature is 1100℃ to 1500℃, for example, it can be 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, or 1500℃, etc. This application can select different heat treatment temperature ranges according to different raw material powders, and no limitation is made here within the above-mentioned temperature range. The second precursor generates supramolecular forces and interpenetration effects during the heat treatment process to solidify, thereby improving the strength, toughness, and density of the ultrathin device.

[0076] In some embodiments, the heat treatment time is 0.5h to 5h, for example, it can be 0.5h, 1h, 2h, 3h, 4h or 5h, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0077] In some embodiments, the heating rate of the heat treatment is 1℃ / min to 15℃ / min, for example, it can be 1℃ / min, 3℃ / min, 5℃ / min, 8℃ / min, 10℃ / min, 13℃ / min or 15℃ / min, etc. Of course, it can also be other values ​​within the above range, which are not limited here.

[0078] In some implementations, the heat treatment is carried out under vacuum conditions to prevent oxygen from entering and oxidizing the second precursor, which would reduce the purity of the ultrathin device and affect its quality.

[0079] In some implementations, the vacuum level of the vacuum condition is less than or equal to 10. -2 Pa, for example, could be 10. -5 10 -4 10 -3 Or 10 -2 "etc." can also be other values ​​within the above range, and there are no restrictions here.

[0080] In some embodiments, the heat treatment process includes post-processing steps on the heat-treated material, such as grinding, polishing, and electroplating, to improve the physical and mechanical properties of the ultrathin device.

[0081] This application also provides an ultrathin device prepared by the above-described manufacturing method. The ultrathin device has a specific shape and a thickness of less than or equal to 1 mm, which can effectively fill the gap in the application field of ultrathin devices prepared by powder metallurgy.

[0082] This application also provides the application of the above-mentioned ultra-thin devices in the manufacture of motors, engines, speakers, receivers, buzzers, microphones, miniature vibration motors and headphones, which is beneficial to improving the precision and thinness of the above-mentioned devices.

[0083] The embodiments of the present invention will be further described below with reference to several examples. However, the embodiments of the present invention are not limited to the specific embodiments described below. Appropriate modifications can be made within the scope of the original claims.

[0084] Example 1:

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

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

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

[0088] (4) The second precursor from step (3) is sent into a vacuum sintering furnace for sintering treatment. The sintering temperature is 1200℃ and the sintering time is 3h. After sintering, it is ground and polished to obtain an ultra-thin device.

[0089] Example 2:

[0090] (1) Weigh 100g of ferroalloy powder, 20g of polyvinylpyrrolidone and 3g of water and mix them to obtain a mixed slurry. The average surface area particle size of the ferroalloy powder is 1-5μm and the particle size of the ferroalloy powder satisfies: D90 / D10≤7.

[0091] (2) The mixed slurry from step (1) is dried by a centrifugal spray dryer with an inlet air temperature of 80°C and an outlet air temperature of 100°C to obtain a granular first precursor. The average particle size of the first precursor is 40-80 μm and the flowability is less than 30 s / 50 g.

[0092] (3) The first precursor from step (2) is loaded into the hopper of the servo press and conveyed to the mold cavity through the material pipe. The shape of the mold cavity is as follows: Figure 4 As shown, the pressure is 300-1200 MPa, the time is 2-20 s, and the accuracy is 2 μm to obtain the second precursor.

[0093] (4) The second precursor from step (3) is sent into a vacuum sintering furnace for sintering treatment. The sintering temperature is 1200℃ and the sintering time is 3h. After sintering, it is ground and polished to obtain an ultra-thin device.

[0094] Twenty different ultrathin devices were fabricated using specific process parameters selected according to the fabrication process given in Example 1 of this application. Ten different ultrathin devices were fabricated using specific process parameters selected according to the fabrication process given in Example 2. 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 worktable and fixing it. A dial indicator was installed so that it could contact the measuring surface. The target ultrathin device was moved to distribute the measurement position evenly, and the reading of the dial indicator was read. The maximum value of the deviation was taken as the flatness.

[0095] like Figure 3 The figure shows the dimensional measurement results of the ultrathin device prepared in Example 1. Figure 3 It can be seen that the thickness of the ultrathin device in Example 1 of this 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 this application can produce ultrathin devices with high precision.

[0096] like Figure 5The figure shows the dimensional measurement results of the ultrathin device prepared in Example 2. Figure 5 It can be seen that: Selecting Figure 5 Thickness measurements were taken at two different locations. The thickness of location 1 was between 0.450 mm and 0.485 mm, and the thickness of location 2 was between 0.150 mm and 0.180 mm. The values ​​were relatively uniform, indicating that the preparation method of this application can produce ultra-thin devices with high precision.

[0097] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0098] Although this application discloses preferred embodiments as described above, it is not intended to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A method for fabricating an ultrathin device, characterized in that, Includes the following steps: A mixture containing raw material powder, binder and solvent is granulated by spray drying to obtain a first precursor. The raw material powder includes metal material powder and / or ceramic material powder. The average surface area particle size of the raw material powder is 1μm~15μm. The mass ratio of the raw material powder to the binder is 100:(1~10). The average surface area particle size of the first precursor is 40μm~80μm. The flowability of the first precursor is less than 30s / 50g. The first precursor is placed in a molding mold of a preset shape and subjected to pressure treatment to obtain a second precursor, the second precursor having a preset shape; The second precursor is heat-treated to obtain the ultrathin device, the thickness of which is less than or equal to 1 mm.

2. The preparation method according to claim 1, characterized in that, The metal material powder contains at least one of elemental metals and alloys. The elemental metals include at least one of iron, cobalt, nickel, chromium, and manganese. The alloys include at least one of iron alloys, copper alloys, nickel alloys, cobalt alloys, aluminum alloys, and titanium alloys.

3. The preparation method according to claim 1, characterized in that, The ceramic material powder includes at least one of alumina 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, characterized in that, The particle size of the raw material powder satisfies: D90 / D10≤7.

5. The preparation method according to claim 1, characterized in that, The adhesive includes a thermoplastic adhesive, which includes at least one of polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol.

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

7. The preparation method according to claim 1, 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, characterized in that, The inlet air temperature of the spray dryer is 50℃~300℃, and the outlet air temperature of the spray dryer is 90℃~200℃.

9. The preparation method according to claim 1, 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, characterized in that, The pressurization equipment includes a servo press, the displacement accuracy of which is 1μm~3μm.

11. The preparation method according to claim 1, characterized in that, The pressure of the pressurization process is 300 MPa to 1200 MPa, and the pressurization time is 2s to 20s.

12. The preparation method according to claim 1, characterized in that, The molding die is made of steel, including at least one of ASP23, ASP60, tungsten steel, SKD11, Cr12MoV and DC53.

13. The preparation method according to claim 1, characterized in that, The heat treatment satisfies: The temperature of the heat treatment is 1100℃~1500℃; The heat treatment time is 0.5h to 5h; The heating rate of the heat treatment is 1℃ / min ~ 15℃ / min; The heat treatment is performed under vacuum conditions, wherein the vacuum level is less than or equal to 10. -2 Pa.

14. An ultrathin device prepared by the preparation method according to any one of claims 1 to 13, characterized in that, The thickness of the ultrathin device is less than or equal to 1 mm.

15. The use of an ultrathin device prepared by the preparation method according to any one of claims 1 to 13 or the ultrathin device according to claim 14 in the preparation of motors, engines, loudspeakers, receivers, buzzers, microphones, micro vibration motors and headphones.

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