Low-warping-degree aluminum oxide ceramic sintering method and aluminum oxide ceramic

Abstract

The invention discloses a low-warping-degree aluminum oxide ceramic sintering method and aluminum oxide ceramic. The method comprises the following steps: preparing aluminum oxide granulation powder into a plurality of aluminum oxide green bodies with target sizes; a plurality of aluminum oxide green bodies are placed on a load bearing plate in an overlapped mode, bearing object layers are clamped between any two adjacent aluminum oxide green bodies and between the lowest aluminum oxide green body and the load bearing plate, and the bearing object layers are formed by arranging a plurality of bearing objects at intervals. The area coverage rate of the carrier in each carrier layer on the surface of the alumina green body in contact with the carrier layer is 40-80%; and sintering the alumina green body on the setter plate to obtain an alumina ceramic finished product. The process is simple to operate, and the warping degree of the prepared low-alumina ceramic finished product can be effectively reduced.

Description

Technical Field

[0001] The present application belongs to the field of preparation of alumina ceramics, and in particular to a sintering method of alumina ceramics with low warpage and alumina ceramics. Background Art

[0002] With the development of the information age, the demand for high-quality chips in human life is increasing, which has promoted the development of etching technology, thus putting forward higher requirements for the hardness, wear resistance, physical and chemical stability of the cavity of semiconductor etching equipment. Alumina ceramics have the advantages of high hardness, high strength, excellent wear resistance and chemical corrosion resistance, and are widely used in the cavity of semiconductor etching equipment. In the existing alumina ceramic sintering method, a single-layer alumina green body is usually placed on a support plate for sintering, and corundum sand is placed between the alumina green body and the support plate as a carrier for supporting the alumina green body. During the high-temperature sintering process of alumina, when the alumina green body shrinks and deforms, its surface is very likely to cause the alumina ceramic to warp due to uneven force, and during the shrinkage and deformation of the alumina green body, the alumina green body will produce friction with the carrier below it, thereby further increasing the warping of the finished alumina ceramic, especially when the size of the alumina green body is large, the degree of warping is more serious, resulting in an increase in the scrap rate and increased material and production costs.

[0003] Therefore, how to ensure that alumina ceramics do not warp due to uneven force during high-temperature sintering, thereby reducing the warping of alumina ceramics, is a problem that needs to be solved urgently in this field. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a method for sintering low-warpage alumina ceramics and alumina ceramics, which have simple process operations and can effectively reduce the warpage of the obtained low-warpage alumina ceramic products.

[0005] The first object of the present application is to provide a method for sintering alumina ceramics with low warpage.

[0006] The above application purpose 1 is achieved through the following technical solutions:

[0007] A method for sintering alumina ceramics with low warpage comprises the following steps:

[0008] S1, forming alumina granulated powder into a plurality of alumina green bodies of target size;

[0009] S2, placing a plurality of the alumina green sheets on a support plate, with a support layer sandwiched between any two adjacent alumina green sheets and between the bottom layer of the alumina green sheets and the support plate, wherein the support layer is composed of a plurality of support materials arranged at intervals, and the area coverage of the support materials in each support layer on the surface of the alumina green sheets in contact with the support materials is between 40% and 80%;

[0010] S3, sintering the alumina green body on the support plate to obtain a finished alumina ceramic product.

[0011] Preferably, the support is corundum sand, hollow alumina balls or porous ceramic pads.

[0012] Preferably, the support is hollow alumina spheres.

[0013] Preferably, the area coverage of the support in each support layer on the surface of the alumina green body in contact with the support is 70%.

[0014] Preferably, the plurality of carriers of the carrier layer are evenly distributed.

[0015] Correspondingly, in step S3, multiple cycles of heating and heat preservation are performed during the sintering process, wherein the starting temperature of the first heating is room temperature 25°C, and the ending temperature of the last heating is 1650°C. The starting temperature and ending temperature of each heating are increased successively, the heating rate of each heating is the same or different, and the heat preservation time of each heating is the same or different.

[0016] Preferably, in step S3, sintering the alumina green body on the setter plate to obtain the alumina ceramic finished product comprises:

[0017] S31, heating from room temperature 25°C to 150°C-160°C at a heating rate of 0.18±0.03°C / min and keeping the temperature for 240 min;

[0018] S32, heating from 300 °C to 600 °C at a heating rate of 0.33 ± 0.03 °C / min and keeping at this temperature for 240 min;

[0019] S33, heating from 600°C to 1000°C at a heating rate of 0.33±0.03°C / min and keeping at that temperature for 120 min, then heating to 1200°C at a heating rate of 0.67±0.03°C / min and keeping at that temperature for 240 min, then heating to 1450°C at a heating rate of 0.7±0.03°C / min and keeping at that temperature for 120 min;

[0020] S34, heating from 1450°C to 1550°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 120 min, then heating to 1650°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 240 min;

[0021] S35, waiting for the ceramic body to cool naturally to room temperature, and obtaining an alumina ceramic finished product.

[0022] Preferably, in step S1, the step of preparing alumina granulated powder into a plurality of alumina green bodies of target size comprises:

[0023] The alumina granulated powder is subjected to cold isostatic pressing and then mechanically processed to obtain a plurality of alumina green bodies of target size.

[0024] Preferably, the cold isostatic pressing pressure is 130 MPa, and the holding time is 300 s.

[0025] The second object of the present application is to provide an alumina ceramic.

[0026] The second purpose of the above application is achieved through the following technical solutions:

[0027] An alumina ceramic is prepared by the low-warpage alumina ceramic sintering method as described in any one of the above application objectives.

[0028] The above technical solution of the present application has the following advantages compared with the prior art:

[0029] The present application arranges a plurality of alumina green sheets on a firing plate in an overlapping manner, and sandwiches a plurality of carriers between any two adjacent alumina green sheets and between the bottommost alumina green sheets and the firing plate to form a carrier layer, and the area coverage of the carriers in each carrier layer on the surface of the alumina green sheets in contact with it is between 40% and 80%. In this way, the overall thickness of the alumina green sheets to be sintered on the firing plate is increased, thereby improving the rigidity of the overall structure. Through multi-layer stacking, the distribution environment around each alumina green sheet is similar, so that the temperature field distribution around each alumina green sheet is more uniform, so that each alumina green sheet shrinks uniformly during the sintering process, so that the stresses generated by the shrinkage deformation of the two adjacent layers can offset each other to achieve stress balance, so that no friction is generated between each alumina green sheet and the carrier in contact with it, and the problem of increased warping caused by the stress generated by the shrinkage deformation of the alumina green sheet and the friction between the carrier during single-layer sintering is avoided. In summary, the alumina ceramic sintering process is simple to operate, can effectively reduce the warpage of the low alumina ceramic products, improve product quality, and reduce the scrap rate during the alumina sintering process, thereby reducing material and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of a process for sintering alumina ceramics with low warpage in one embodiment of the present application;

[0032] Figure 2 This is a schematic diagram of a process for sintering an alumina green body on a setter plate in one embodiment of the present application;

[0033] Figure 3 This is a schematic diagram of the structure in which multiple alumina green bodies are stacked and placed on a support plate for sintering in an embodiment of the present application;

[0034] Figure 4 This is a schematic diagram of the structure in which a single alumina green body is placed on a support plate for sintering in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] In the embodiments provided in the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are merely schematic. For example, the division of units and modules is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or modules can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0037] In addition, all functional units in the embodiments of the present application may be integrated into one processor, or each unit may be a separate device, or two or more units may be integrated into one device; each functional unit in the embodiments of the present application may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0038] A person skilled in the art can understand that all or part of the steps of the following method embodiments can be completed by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the following method embodiments are executed; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM), a magnetic disk or an optical disk, and other media that can store program codes.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0040] like Figure 1 As shown, the embodiment of the present application provides a method for sintering alumina ceramics with low warpage, which may include the following steps:

[0041] S1, forming alumina granulated powder into a plurality of alumina green bodies of target size;

[0042] S2, placing a plurality of alumina green sheets on a support plate, with a support layer sandwiched between any two adjacent alumina green sheets and between the bottom alumina green sheets and the support plate, wherein the support layer is composed of a plurality of support materials arranged at intervals, and the support materials in each support layer have an area coverage rate of 40% to 80% on the surface of the alumina green sheets in contact with the support materials;

[0043] S3, sintering the alumina green body on the support plate to obtain a finished alumina ceramic product.

[0044] It should be noted that the area coverage of the support on the surface of the alumina green body in contact with the support refers to the ratio of the total area of ​​the projection of the support on the surface of the alumina green body in contact with the support to the area of ​​the surface of the alumina green body in contact with the support.

[0045] The low warpage alumina ceramic sintering method of the present embodiment is as follows: first, alumina granulated powder is made into multiple alumina green bodies of target size, and then the multiple alumina green bodies are overlapped and placed on a firing plate, and a carrier layer composed of a plurality of carriers arranged at intervals is sandwiched between any two adjacent alumina green bodies and between the bottom layer of the alumina green bodies and the firing plate, and the area coverage of the carriers in each carrier layer on the surface of the alumina green bodies in contact with the carriers is between 40% and 80%; finally, the alumina green bodies on the firing plate are sintered to obtain finished alumina ceramics.

[0046] In this embodiment, a plurality of alumina green sheets are overlapped and placed on a supporting plate, and a supporting material layer is formed by placing a plurality of supporting materials between any two adjacent alumina green sheets and between the bottom layer of alumina green sheets and the supporting plate, and the area coverage of the supporting materials in each supporting material layer on the surface of the alumina green sheets in contact with it is between 40% and 80%. In this way, the overall thickness of the alumina green sheets to be sintered on the supporting plate is increased, thereby improving the rigidity of the overall structure. Through multi-layer stacking, the distribution environment around each alumina green sheet is similar, so that the temperature field distribution around each alumina green sheet is more uniform, so that each alumina green sheet shrinks uniformly during the sintering process, so that the stresses generated by the shrinkage deformation of the two adjacent layers can offset each other to achieve stress balance, so that no friction is generated between each alumina green sheet and the supporting material in contact with it, thereby avoiding the problem of increased warping caused by the friction between the stress generated by the shrinkage deformation of the alumina green sheet and the supporting material during single-layer sintering.

[0047] In summary, the alumina ceramic sintering process in this embodiment is simple to operate, can effectively reduce the warpage of the low alumina ceramic product, improve product quality, and reduce the scrap rate in the alumina sintering process, thereby reducing material and production costs.

[0048] Specifically, the support may be corundum sand, hollow alumina balls or porous ceramic pads.

[0049] In one embodiment, the carrier is a hollow alumina ball. In this embodiment, the hollow alumina ball is used to support the alumina green body during the sintering process, so that the alumina green body is point-supported during the sintering process, and the friction between the alumina green body and the carrier is reduced; when the alumina green body shrinks during the sintering process, the shrinkage resistance of the carrier to the alumina green body is reduced, so that the surface of the alumina green body shrinks uniformly, thereby further reducing the warpage of the finished alumina ceramic product.

[0050] In one embodiment, the area coverage of the support material in each support material layer on the surface of the alumina green body in contact with the support material layer is 70%.

[0051] In one embodiment, the carriers of the carrier layer are evenly distributed.

[0052] Correspondingly, in step S3, multiple cycles of heating and heat preservation are performed during the sintering process, wherein the starting temperature of the first heating is room temperature 25°C, and the ending temperature of the last heating is 1650°C. The starting temperature and ending temperature of each heating are increased successively, the heating rate of each heating is the same or different, and the heat preservation time of each heating is the same or different.

[0053] like Figure 2 As shown, in one embodiment, in step S3, sintering the alumina green body on the setting plate to obtain the alumina ceramic finished product includes:

[0054] S31, heating from room temperature 25°C to 150°C-160°C at a heating rate of 0.18±0.03°C / min and keeping the temperature for 240 min;

[0055] S32, heating from 300 °C to 600 °C at a heating rate of 0.33 ± 0.03 °C / min and keeping at this temperature for 240 min;

[0056] S33, heating from 600°C to 1000°C at a heating rate of 0.33±0.03°C / min and keeping at that temperature for 120 min, then heating to 1200°C at a heating rate of 0.67±0.03°C / min and keeping at that temperature for 240 min, then heating to 1450°C at a heating rate of 0.7±0.03°C / min and keeping at that temperature for 120 min;

[0057] S34, heating from 1450°C to 1550°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 120 min, then heating to 1650°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 240 min;

[0058] S35, waiting for the ceramic body to cool naturally to room temperature, and obtaining an alumina ceramic finished product.

[0059] In one embodiment, in step S1, forming a plurality of alumina green bodies of target size from alumina granulated powder comprises:

[0060] The alumina granulated powder is subjected to cold isostatic pressing and then mechanically processed to obtain a plurality of alumina green bodies of target size.

[0061] In one embodiment, the cold isostatic pressing pressure is 130 MPa, and the holding time is 300 s.

[0062] In order to better understand the advantages of the low-warpage alumina ceramic sintering method of the embodiment of the present application, its technical effects are demonstrated and explained with multiple embodiments and a comparative example below.

[0063] Embodiment 1:

[0064] The specific process is as follows:

[0065] Step 1, cold isostatically press the alumina granulated powder at 130 MPa for 300 seconds, and then mechanically process and shape the alumina green bodies with a size of 1211*268*14 mm;

[0066] Step 2: Place a single piece of alumina green body on a sintering plate (such as Figure 4 As shown), the coverage of corundum sand relative to alumina green body is 70%;

[0067] Step 3: Sintering the alumina green body on the setter plate. The specific process is as follows:

[0068] Step 3.1, heating from room temperature 25°C to 150°C at a heating rate of 0.18°C / min and keeping the temperature for 240 min;

[0069] Step 3.2, heating from 300°C to 600°C at a heating rate of 0.33°C / min and keeping at this temperature for 240 min;

[0070] Step 3.3, heating from 600°C to 1000°C at a heating rate of 0.33°C / min and keeping the temperature for 120 min, then heating to 1200°C at a heating rate of 0.67°C / min and keeping the temperature for 240 min, then heating to 1450°C at a heating rate of 0.7°C / min and keeping the temperature for 120 min;

[0071] Step 3.4, heating from 1450°C to 1550°C at a heating rate of 0.55°C / min and keeping the temperature for 120 min, then heating to 1650°C at a heating rate of 0.55°C / min and keeping the temperature for 240 min;

[0072] Step 3.5, wait for the ceramic body to cool naturally to room temperature to obtain the finished alumina ceramic product.

[0073] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body (the distance between the highest and lowest points of the warpage) was 3.2-3.9mm, and the warpage in the length direction (warpage height divided by length) was calculated to be 0.32%-0.39%.

[0074] Embodiment 2:

[0075] The specific process is as follows:

[0076] The implementation steps of this embodiment are basically the same as those of Embodiment 1, the only difference being that the carrier in Step 2 is replaced by hollow alumina balls instead of corundum sand.

[0077] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body (the distance between the highest and lowest points of the warpage) was 1.8-2.4mm, and the warpage in the length direction (warpage height divided by length) was calculated to be 0.18%-0.24%.

[0078] Embodiment 3:

[0079] The specific process is as follows:

[0080] Step 1, cold isostatically press the alumina granulated powder at 130 MPa for 300 seconds, and then mechanically process and shape the alumina green bodies with a size of 1211*268*14 mm;

[0081] Step 2: Place three alumina green sheets on top of each other on a firing plate, and place evenly distributed alumina hollow balls (such as Figure 3 As shown), the coverage of the alumina hollow spheres relative to the alumina green body is 40%;

[0082] Step 3: Sintering the alumina green body stacked on the setter plate. The specific process is as follows:

[0083] Step 3.1, heating from room temperature 25°C to 150°C at a heating rate of 0.18°C / min and keeping the temperature for 240 min;

[0084] Step 3.2, heating from 300°C to 600°C at a heating rate of 0.33°C / min and keeping at this temperature for 240 min;

[0085] Step 3.3, heating from 600°C to 1000°C at a heating rate of 0.33°C / min and keeping the temperature for 120 min, then heating to 1200°C at a heating rate of 0.67°C / min and keeping the temperature for 240 min, then heating to 1450°C at a heating rate of 0.7°C / min and keeping the temperature for 120 min;

[0086] Step 3.4, heating from 1450°C to 1550°C at a heating rate of 0.55°C / min and keeping the temperature for 120 min, then heating to 1650°C at a heating rate of 0.55°C / min and keeping the temperature for 240 min;

[0087] Step 3.5, wait for the ceramic body to cool naturally to room temperature to obtain the finished alumina ceramic product.

[0088] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 1.5-2.1mm, and the warpage in the length direction was calculated to be 0.15%-0.21%.

[0089] Embodiment 4:

[0090] The implementation steps of this embodiment are basically the same as those of embodiment 3, the only difference being that the coverage of the alumina hollow spheres relative to the alumina green body in step 2 is 50%.

[0091] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 1.3-1.7mm, and the warpage in the length direction was calculated to be 0.13%-0.17%.

[0092] Embodiment 5:

[0093] The implementation steps of this embodiment are basically the same as those of embodiment 3, the only difference being that the coverage of the alumina hollow spheres relative to the alumina green body in step 2 is 70%.

[0094] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 1.0-1.4mm, and the warpage in the length direction was calculated to be 0.10%-0.14%.

[0095] Embodiment 6:

[0096] The implementation steps of this embodiment are basically the same as those of embodiment 3, the only difference being that the coverage of the alumina hollow spheres relative to the alumina green body in step 2 is 80%.

[0097] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 1.1-1.6mm, and the warpage in the length direction was calculated to be 0.11%-0.16%.

[0098] Embodiment 7:

[0099] The implementation steps of this embodiment are basically the same as those of Embodiment 5, with the only difference being that the support in Step 2 is replaced by a porous ceramic pad from alumina hollow spheres.

[0100] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 1.2-1.7mm, and the warpage in the length direction was calculated to be 0.12%-0.17%.

[0101] Embodiment 8:

[0102] The implementation steps of this embodiment are basically the same as those of Embodiment 5, the only difference being that the carrier in Step 2 is replaced by corundum sand instead of hollow alumina spheres.

[0103] After sintering, the warpage of the finished alumina ceramics was measured. The size of the finished alumina ceramics was about 1010*220*12mm, the warpage height of the ceramic body was 2.8-3.5mm, and the warpage in the length direction was calculated to be 0.28%-0.35%.

[0104] The experimental results comparison table of the above 8 embodiments is as follows:

[0105] Experimental results comparison table

[0106]

[0107]

[0108] In the above 8 embodiments, embodiment 1 is the prior art (i.e., comparative example), that is, the alumina green body is sintered in a single layer, the support is corundum sand, and the coverage of the corundum sand relative to the alumina green body is 70%;

[0109] Examples 2 to 8 analyze the advantages of the present application from three aspects: the number of stacked layers of the sintered alumina green body, the type of the support, and the coverage of the support relative to the surface of the alumina green body.

[0110] By comparing the measurement results of the above 8 embodiments, it can be seen that:

[0111] Compared with Example 1, in Examples 2 to 8, the warpage of the alumina ceramic products obtained after sintering is significantly reduced, indicating that the alumina ceramic sintering method of the present application can significantly reduce the warpage of the alumina ceramic products. The specific analysis is as follows:

[0112] 1. Compared with Example 1, in Example 2, the carrier adopts hollow alumina balls, and the warpage of the alumina ceramic product obtained after sintering is significantly reduced, which indicates that the hollow alumina balls are used to support the alumina green body during the sintering process, so that the point support of the alumina green body during the sintering process is achieved, and the friction between the alumina green body and the carrier is reduced; when the alumina green body shrinks during the sintering process, the shrinkage resistance of the carrier to the alumina green body is reduced, so that the surface of the alumina green body shrinks uniformly, thereby further reducing the warpage of the alumina ceramic product;

[0113] 2. Compared with Example 8 (the support material is corundum sand) and Example 7 (the support material is porous ceramic pads), the support material in Example 5 is alumina hollow balls, and the warping of the alumina ceramic product obtained after sintering is significantly reduced compared with that of Example 7 and Example 8, further illustrating that the use of alumina hollow balls to support alumina green bodies can effectively reduce the warping of alumina ceramic products.

[0114] 3. Compared with Example 1, the alumina green body in Example 8 is fired in three layers, and the warpage of the alumina ceramic product obtained after sintering is significantly reduced compared with that of single-layer sintering, indicating that the overall thickness of the alumina green body to be sintered on the supporting plate is increased by multi-layer firing, thereby improving the rigidity of the overall structure. In addition, the distribution environment around each alumina green body is similar through multi-layer firing, so that the temperature field distribution around each alumina green body is more uniform, so that each alumina green body shrinks uniformly during the sintering process, so that the stress generated by the shrinkage deformation of the two adjacent layers can offset each other to achieve stress balance, so that no friction is generated between each alumina green body and the carrier in contact with it, thereby avoiding the problem of increased warpage caused by the stress generated by the shrinkage deformation of the alumina green body and the friction between the carrier during single-layer sintering.

[0115] 4. Compared with Example 2, the alumina green body in Example 5 adopts three-layer stacking firing, and the warpage of the alumina ceramic product obtained after sintering is significantly reduced compared with single-layer sintering, further indicating that multi-layer stacking firing can effectively reduce the warpage of the alumina ceramic product.

[0116] 5. Examples 3 to 6 all adopt a multi-layer stacking firing method, and the carriers are all hollow alumina balls, but the coverage of the carriers on the surface of the alumina green body is different. Among them, when the coverage is 70%, the warping of the alumina ceramic product obtained after sintering is the smallest, indicating that a coverage of about 70% is the best choice.

[0117] In addition, the present application can also effectively improve the sintering efficiency through multi-layer stacking.

[0118] An embodiment of the present application also provides an alumina ceramic, which is prepared by the low-warpage alumina ceramic sintering method described in any of the above embodiments.

[0119] Since the alumina ceramic is prepared by the low-warpage alumina ceramic sintering method in any of the above embodiments, the alumina ceramic has the advantage of low warpage.

[0120] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0121] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this embodiment can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0122] The steps of the method or algorithm described in the embodiments disclosed in this embodiment can be directly implemented by hardware, software modules executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the technical field.

[0123] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined in the present embodiment may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present embodiment, but will conform to the widest scope consistent with the principles and novel features disclosed in the present embodiment.

Claims

1. A method for sintering alumina ceramics with low warpage, characterized in that: The steps include: S1, forming alumina granulated powder into a plurality of alumina green bodies of target size; S2, placing a plurality of the alumina green sheets on a support plate, with a support layer sandwiched between any two adjacent alumina green sheets and between the bottom layer of the alumina green sheets and the support plate, wherein the support layer is composed of a plurality of support materials arranged at intervals, and the area coverage of the support materials in each support layer on the surface of the alumina green sheets in contact with the support materials is between 40% and 80%; S3, sintering the alumina green body on the support plate to obtain a finished alumina ceramic product.

2. The method for sintering alumina ceramics with low warpage according to claim 1, characterized in that: The support is corundum sand, hollow alumina balls or porous ceramic pads.

3. The method for sintering alumina ceramics with low warpage according to claim 2, characterized in that: The support is hollow alumina sphere.

4. The method for sintering alumina ceramics with low warpage according to claim 3, characterized in that: In step S2, the area coverage of the support in each support layer on the surface of the alumina green body in contact with the support is 70%.

5. The method for sintering alumina ceramics with low warpage according to claim 1, characterized in that: The plurality of carriers in the carrier layer are evenly distributed.

6. The method for sintering alumina ceramics with low warpage according to any one of claims 1 to 5, characterized in that: In step S3, multiple cycles of heating and heat preservation are performed during the sintering process, wherein the starting temperature of the first heating is room temperature 25°C, and the ending temperature of the last heating is 1650°C. The starting temperature and ending temperature of each heating are increased successively, and the rate of each heating is the same or different, and the heat preservation time of each time is the same or different.

7. The method for sintering alumina ceramics with low warpage according to claim 6, characterized in that: In step S3, sintering the alumina green body on the setter plate to obtain the alumina ceramic finished product comprises: S31, heating from room temperature 25°C to 150°C-160°C at a heating rate of 0.18±0.03°C / min and keeping the temperature for 240 min; S32, heating from 300 °C to 600 °C at a heating rate of 0.33 ± 0.03 °C / min and keeping at this temperature for 240 min; S33, heating from 600°C to 1000°C at a heating rate of 0.33±0.03°C / min and keeping at that temperature for 120 min, then heating to 1200°C at a heating rate of 0.67±0.03°C / min and keeping at that temperature for 240 min, then heating to 1450°C at a heating rate of 0.7±0.03°C / min and keeping at that temperature for 120 min; S34, heating from 1450°C to 1550°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 120 min, then heating to 1650°C at a heating rate of 0.55±0.03°C / min and keeping at that temperature for 240 min; S35, waiting for the ceramic body to cool naturally to room temperature, and obtaining an alumina ceramic finished product.

8. The method for sintering alumina ceramics with low warpage according to claim 1, 2, 3, 4, 5 or 7, characterized in that: In step S1, the step of preparing alumina granulated powder into a plurality of alumina green bodies of target size comprises: The alumina granulated powder is subjected to cold isostatic pressing and then mechanically processed to obtain a plurality of alumina green bodies of target size.

9. The method for sintering alumina ceramics with low warpage according to claim 8, characterized in that: The cold isostatic pressing pressure is 130 MPa, and the holding time is 300 s.

10. An alumina ceramic, characterized in that: The low-warpage alumina ceramic is prepared by the sintering method according to any one of claims 1 to 9.

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