Method and system for producing and forming silicon carbide ceramic sealing part

Abstract

The invention relates to the field of silicon carbide ceramic materials, in particular to a method and a system for producing and forming a silicon carbide ceramic sealing component, and the method comprises the following steps of: performing compression molding on pre-dried silicon carbide slurry based on deformation characteristics of the silicon carbide slurry in a pre-drying process and shape tolerance characteristics of the sealing component; based on the internal structure change characteristics of the green body in the sintering process, a sintering abnormal area of the green body is recognized, and sintering operation parameters of the sintering abnormal area are adjusted; and based on the global cooling characteristic of the silicon carbide ceramic sealing component, estimating the internal stress difference characteristic between parts with different sizes in the silicon carbide ceramic sealing component, and adjusting the active cooling operation parameters of the silicon carbide ceramic sealing component. According to the method, the generation and forming procedures can be regulated and controlled for the silicon carbide ceramic sealing part in an irregular shape, the micropore distribution and internal stress distribution uniformity is improved, and the bending strength and the wear-resistant lubricating property are improved.

Description

Technical Field

[0001] The present invention relates to the field of silicon carbide ceramic materials, and particularly to a production and molding method and system for silicon carbide ceramic sealing components. Background Art

[0002] Silicon carbide ceramics have the characteristics of low density, high hardness, good wear resistance, high temperature resistance, corrosion resistance, etc., and are widely used in the production of mechanical components. Silicon carbide ceramic sealing components can meet the requirements of high mechanical sealing performance and low friction loss in different scenarios. For regular-shaped sealing components such as silicon carbide ceramic sealing rings and sealing gaskets, finished sealing components can be obtained only through processes such as raw material mixing, molding by pressing, and sintering, without the need to additionally consider the non-uniform stress distribution caused by non-uniform cooling during the sintering process of silicon carbide materials.

[0003] In actual scenarios, more irregular-shaped silicon carbide ceramic sealing components are needed to meet the sealing requirements of special-shaped mechanical equipment. Considering the anisotropy of the structural dimensions of irregular-shaped silicon carbide ceramic sealing components in three-dimensional space, it will affect the degree of fusion of silicon carbide materials in different parts during sintering and the cooling efficiency of different parts during cooling. The spatial difference in the degree of fusion of silicon carbide materials in different parts of the sealing component results in the inability to uniformly form a microporous structure in the sealing component, reducing the uniform penetration of lubricant inside the sealing component; in addition, the spatial difference in the cooling efficiency of different parts inside the sealing component leads to non-uniform stress distribution in the sealing component, reducing the bending strength of the sealing component. Therefore, how to detect and regulate the production and molding of irregular-shaped silicon carbide ceramic sealing components to improve the uniformity of the internal micropore distribution and stress distribution of the sealing component is of great significance for improving the bending strength and wear resistance and lubricity of silicon carbide ceramic sealing components. Summary of the Invention

[0004] In order to address the spatial differences in the degree of fusion of silicon carbide materials and the cooling efficiency caused by the production and molding of irregular-shaped silicon carbide ceramic sealing components, corresponding adjustments are made in processes such as molding by pressing, sintering, and cooling to improve the uniformity of the internal micropore distribution and stress distribution of the sealing component and enhance the wear resistance, lubricity, and bending strength of the silicon carbide ceramic sealing component. The present invention provides a production and molding method for silicon carbide ceramic sealing components, and the method includes the following steps: S1: Obtain the deformation characteristics of silicon carbide slurry during pre-drying, and based on the deformation characteristics and the outer tolerance characteristics of the sealing component, perform molding by pressing on the pre-dried silicon carbide slurry to obtain a green body; S2: Obtain the internal structure change characteristics of the green body during sintering. Based on the internal structure change characteristics, identify the sintering abnormal area of the green body, and adjust the sintering operation parameters of the sintering abnormal area; S3: Conduct thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component; Based on the global cooling characteristics, estimate the internal stress difference characteristics between different parts inside the sealing component, and thereby adjust the active cooling operation parameters of the sealing component.

[0005] Preferably, in S1, obtain the deformation characteristics of the silicon carbide slurry during pre-drying. Based on the deformation characteristics and the outer contour tolerance characteristics of the sealing component, perform molding pressing on the silicon carbide slurry that has completed pre-drying to obtain a green body. Specifically: Conduct visible light vision identification and absorption spectrum identification on the silicon carbide slurry during pre-drying to obtain the volume change data and solvent content change data of the silicon carbide slurry during pre-drying; Based on the volume change data and the solvent content change data, obtain the correlation characteristics between the volume shrinkage rate and the solvent content reduction rate of the silicon carbide slurry during pre-drying, and use this as the deformation characteristics of the silicon carbide slurry during pre-drying; Based on the deformation characteristics and the outer contour tolerance characteristics of the sealing component, determine the volume of the silicon carbide slurry that has completed pre-drying required for molding pressing, and thereby mold the corresponding volume of the silicon carbide slurry into a green body; wherein, the outer contour tolerance characteristics of the sealing component refer to the allowable range of volume deviation between the expected volume and the actual volume of the sealing component.

[0006] Preferably, in S2, obtain the internal structure change characteristics of the green body during sintering. Based on the internal structure change characteristics, identify the sintering abnormal area of the green body, and adjust the sintering operation parameters of the sintering abnormal area. Specifically: Conduct thermal infrared vision identification on the green body during sintering to obtain the microporous structure change characteristics inside the green body; wherein, the microporous structure change characteristics include the micropore size change characteristics and micropore distribution density change characteristics inside the green body during sintering; Based on the microporous structure change characteristics, estimate the change trend of the micropore occupation range inside the green body during sintering, and thereby identify the sintering abnormal area of the green body; Based on the micropore size and micropore distribution density of the sintering abnormal area, adjust the sintering heat flow temperature and coverage area output to the sintering abnormal area.

[0007] Preferably, in S3, conduct thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component. Specifically: Perform thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein, the global cooling characteristics refer to the cooling rate characteristics of each part within the sealing component.

[0008] Preferably, in S3, based on the global cooling characteristics, estimate the internal stress difference characteristics between different parts within the sealing component, and adjust the active cooling operation parameters of the sealing component accordingly. Specifically: Based on the global cooling characteristics, determine the change difference in the cooling rate between two adjacent parts with different thicknesses within the sealing component; based on the change difference in the cooling rate, estimate the internal stress difference characteristics between two adjacent parts with different thicknesses; wherein, the internal stress difference characteristics include the magnitude and direction difference characteristics of the internal stress between two adjacent parts with different thicknesses. Based on the internal stress difference characteristics between two adjacent parts with different thicknesses, determine whether an internal stress anisotropy event will occur between the two adjacent parts with different thicknesses; when an internal stress anisotropy event occurs, adjust the flow rate and the air flow delivery coverage area of the active cooling air flow delivered to the two adjacent parts with different thicknesses.

[0009] On the other hand, the present invention provides a production and molding system for a silicon carbide ceramic sealing component, and the system includes the following modules: A deformation identification module, which is used to obtain the deformation characteristics of the silicon carbide slurry during pre-drying; A molding control module, which is used to perform molding on the pre-dried silicon carbide slurry based on the deformation characteristics and the outer shape tolerance characteristics of the sealing component to obtain a green body; A structure change identification module, which is used to obtain the internal structure change characteristics of the green body during sintering; A sintering adjustment module, which is used to identify the sintering abnormal area of the green body based on the internal structure change characteristics and adjust the sintering operation parameters of the sintering abnormal area; A thermal identification module, which is used to perform thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component; A cooling adjustment module, which is used to estimate the internal stress difference characteristics between different parts within the sealing component based on the global cooling characteristics and adjust the active cooling operation parameters of the sealing component accordingly.

[0010] Preferably, the deformation identification module is used to obtain the deformation characteristics of the silicon carbide slurry during pre-drying, specifically: Perform visible light visual recognition and absorption spectrum recognition on the silicon carbide slurry during pre-drying to obtain the volume change data and solvent content change data of the silicon carbide slurry during pre-drying; based on the volume change data and the solvent content change data, obtain the correlation characteristics between the volume shrinkage rate and the solvent content reduction rate of the silicon carbide slurry during pre-drying, and use this as the deformation characteristics of the silicon carbide slurry during pre-drying. The compression molding control module is used to perform compression molding on the pre-dried silicon carbide slurry based on the deformation characteristics and the outer shape tolerance characteristics of the sealing component to obtain a green body, specifically: Based on the deformation characteristics and the outer shape tolerance characteristics of the sealing component, determine the volume of the pre-dried silicon carbide slurry required for compression molding, and use this to compress the corresponding volume of the silicon carbide slurry into a green body; wherein, the outer shape tolerance characteristics of the sealing component refer to the allowable range of volume deviation between the desired volume and the actual volume of the sealing component.

[0011] Preferably, the structure change recognition module is used to obtain the internal structure change characteristics of the green body during sintering, specifically: Perform thermal infrared visual recognition on the green body during sintering to obtain the microporous structure change characteristics inside the green body; wherein, the microporous structure change characteristics include the micropore size change characteristics and the micropore distribution density change characteristics inside the green body during sintering. The sintering adjustment module is used to identify the sintering abnormal area of the green body based on the internal structure change characteristics and adjust the sintering operation parameters of the sintering abnormal area, specifically: Based on the microporous structure change characteristics, estimate the change trend of the micropore occupancy range inside the green body during sintering, and use this to identify the sintering abnormal area of the green body; based on the micropore size and micropore distribution density of the sintering abnormal area, adjust the sintering heat flow temperature and coverage area output to the sintering abnormal area.

[0012] Preferably, the thermal recognition module is used to perform thermal recognition on the sintered sealing component to obtain the global cooling characteristics of the sealing component, specifically: Perform thermal recognition on the sintered sealing component to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein, the global cooling characteristics refer to the cooling rate characteristics of each part inside the sealing component.

[0013] Preferably, the cooling adjustment module is used to estimate the internal stress difference characteristics between different parts inside the sealing component based on the global cooling characteristics, and use this to adjust the active cooling operation parameters of the sealing component, specifically: Based on the global cooling characteristics, determine the difference in the cooling rate change between two adjacent parts with different thicknesses within the sealing component; based on the difference in the cooling rate change, estimate the internal stress difference characteristics between two adjacent parts with different thicknesses; wherein, the internal stress difference characteristics include the magnitude and direction difference characteristics of the internal stress between two adjacent parts with different thicknesses. Based on the internal stress difference characteristics between two adjacent parts with different thicknesses, determine whether an internal stress anisotropy event will occur between the two adjacent parts with different thicknesses; when an internal stress anisotropy event occurs, adjust the flow rate and the air flow delivery coverage area of the active cooling air flow delivered to the two adjacent parts with different thicknesses.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Obtain the deformation characteristics of the silicon carbide slurry during pre-drying, and based on the deformation characteristics and the outer shape tolerance characteristics of the sealing component, perform die pressing on the silicon carbide slurry that has completed pre-drying to obtain a green body. The prepared silicon carbide slurry is not suitable for direct die pressing due to its large solvent content, and the silicon carbide slurry obtained after the sintering process will undergo volume shrinkage, and the volume shrinkage ratio of silicon carbide slurries with different material weight ratios is also different. Considering that the reduction of the solvent content inside the silicon carbide slurry is the cause of volume shrinkage, perform correlation analysis on the volume change data and the solvent content change data of the prepared silicon carbide slurry to obtain the correlation characteristics between the volume shrinkage rate and the solvent content reduction rate of the silicon carbide slurry during pre-drying, providing a reliable reference for determining the required volume of the silicon carbide slurry for die pressing. According to the deformation characteristics of the silicon carbide slurry during pre-drying and the allowable range of the volume deviation between the desired volume and the actual volume of the sealing component, determine the volume of the silicon carbide slurry that has completed pre-drying required for die pressing, so as to accurately determine the volume of the silicon carbide slurry that has completed pre-drying required for die pressing while fully considering the volume shrinkage effect of the silicon carbide slurry and the outer shape volume tolerance range of the sealing component, effectively reducing the probability of forming defective products due to excessive shrinkage of the green body after the sintering process.

[0015] Obtain the internal structure change characteristics of the green body during sintering, and based on the internal structure change characteristics, identify the sintering abnormal area of the green body and adjust the sintering operation parameters of the sintering abnormal area. Based on the micropore size change characteristics and the micropore distribution density change characteristics inside the green body during sintering, estimate the change trend of the occupied range of the micropores inside the green body during sintering, and thereby adaptively reduce the sintering heat flow temperature and the coverage area output to the sintering abnormal area within the allowable sintering temperature range, effectively suppressing the micropore shrinking trend in the sintering abnormal area and enabling the sintering abnormal area to maintain a sufficient number and size of micropore structures.

[0016] Perform thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component; based on the global cooling characteristics, estimate the internal stress difference characteristics between different parts within the sealing component, and adjust the active cooling operation parameters of the sealing component accordingly. In order to timely and accurately suppress the continuous expansion trend of the internal stress difference between different parts within the sealing component, it is necessary to perform global cooling state identification on the sintered sealing component to obtain the cooling situation of each part within the global range of the sealing component, thereby determining the change difference in the cooling rate between two adjacent parts with different thicknesses within the sealing component, and estimating the internal stress magnitude and direction deviation characteristics between two adjacent parts with different thicknesses, and adaptively adjusting the active cooling operation parameters of the sealing component to improve the uniformity of the internal stress distribution of the sealing component. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them: Figure 1 is a flowchart of a production and forming method of a silicon carbide ceramic sealing component provided by the present invention.

[0018] Figure 2 is a relationship curve between the volume shrinkage rate of silicon carbide slurry during pre-drying and the proportion of solvent content.

[0019] Figure 3 is a thermal infrared image of the green body under different sintering conditions during sintering.

[0020] Figure 4 is related to Figure 3 the internal stress distribution diagram of the corresponding green body.

[0021] Figure 5 is a relationship diagram between the flexural stress and compressive stress of the sealing component and temperature during the cooling process.

[0022] Figure 6 is a structural diagram of a production and forming system of a silicon carbide ceramic sealing component provided by the present invention. Detailed Embodiments

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. It can be understood that the specific embodiments described herein are only for explaining the present invention and not for limiting the present invention. Additionally, it should be noted that for the convenience of description, only the parts related to the present invention rather than all the structures are shown in the drawings. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] The terms "comprising" and "having" in the present invention and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products, or devices.

[0025] Referring to the embodiments herein means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0026] Please refer to Figure 1 As shown, the present invention provides a production and forming method for a silicon carbide ceramic sealing component, and the method includes the following steps: S1: Obtain the deformation characteristics of the silicon carbide slurry during pre-drying. Based on the deformation characteristics and the tolerance characteristics of the outer shape of the sealing component, perform die pressing on the silicon carbide slurry that has completed pre-drying to obtain a green body.

[0027] Further, in S1, obtaining the deformation characteristics of the silicon carbide slurry during pre-drying, and based on the deformation characteristics and the tolerance characteristics of the outer shape of the sealing component, performing die pressing on the silicon carbide slurry that has completed pre-drying to obtain a green body, specifically: Perform visible light vision recognition and absorption spectrum recognition on the silicon carbide slurry during pre-drying to obtain the volume change data and solvent content change data of the silicon carbide slurry during pre-drying; based on the volume change data and the solvent content change data, obtain the correlation characteristics between the volume shrinkage rate and the solvent content reduction rate of the silicon carbide slurry during pre-drying, and use this as the deformation characteristics of the silicon carbide slurry during pre-drying; Based on the deformation characteristics and the tolerance characteristics of the outer shape of the sealing component, determine the volume of the silicon carbide slurry that has been pre-dried and is required for molding, and thereby mold the corresponding volume of the silicon carbide slurry into a green body; wherein, the tolerance characteristics of the outer shape of the sealing component refer to the allowable range of volume deviation between the expected volume and the actual volume of the sealing component.

[0028] The production and molding of silicon carbide ceramic sealing components mainly include processes such as slurry preparation, molding, sintering, and cooling in sequence. Slurry preparation is the basis of the entire production and molding process, and the ingredient ratio of the prepared slurry directly affects the molding structure quality of the sealing component. Generally speaking, slurry preparation is to mix materials such as silicon carbide powder, boron carbide powder, sintering aids, binders, dispersants, solvents, etc. according to the corresponding weight ratio to obtain silicon carbide slurry; wherein, the sintering aids can be, but are not limited to, alumina and / or yttrium oxide, the binder can be, but is not limited to, polyvinyl alcohol, the dispersant can be, but is not limited to, polyethyleneimine or organosilane, and the solvent can be, but is not limited to, deionized water and / or absolute ethanol. After the above materials are fully and evenly mixed, a wet silicon carbide slurry is obtained, and the internal cohesion of the silicon carbide slurry is poor. If the silicon carbide slurry is directly molded, it is impossible to ensure that the silicon carbide slurry forms a solid green body. In addition, the solvent in the silicon carbide slurry volatilizes during the sintering process, and the volume shrinkage of the silicon carbide slurry will occur. The volume shrinkage ratio of the silicon carbide slurry is related to the volatilization disappearance ratio of the solvent inside the slurry. The greater the volatilization disappearance ratio of the solvent inside the slurry after the sintering process, the greater the volume shrinkage ratio of the slurry itself after the sintering process, and the volume shrinkage ratios after sintering corresponding to the silicon carbide slurries formed by different material weight ratios are also different under the condition of the same volatilization disappearance ratio of the solvent. If the same volume of silicon carbide slurry is filled into the mold according to the expected volume of the sealing component finished product (for example, the expected volume of the sealing component finished product is , and the volume of the silicon carbide slurry filled into the mold is also ), the actual volume of the finally obtained sealing component finished product will be smaller than the above expected volume due to the shrinkage effect of the slurry, and the finally obtained sealing component will become a waste product due to its too small volume, reducing the production yield of the sealing component.

[0029] From the above analysis, it can be seen that the silicon carbide slurry directly prepared is not suitable for direct molding due to its large solvent content, and the silicon carbide slurry directly prepared will undergo volume shrinkage during the sintering process, and the volume shrinkage ratios of silicon carbide slurries with different material weight ratios are also different. In order to make the silicon carbide slurry have sufficient viscosity and formability for molding and to pre-determine the volume shrinkage ratio of the silicon carbide slurry due to solvent volatilization, pre-drying treatment is carried out after the silicon carbide slurry is prepared, and the pre-drying treatment can be achieved by irradiating the silicon carbide slurry with infrared microwaves or heating the silicon carbide slurry at a matching temperature. During the pre-drying process of the silicon carbide slurry, the solvent will volatilize to a certain extent, causing the volume of the silicon carbide slurry to shrink accordingly. At this time, identifying the silicon carbide slurry can obtain the volume change and solvent residue amount of the silicon carbide slurry itself during the pre-drying process, providing a reliable basis for determining the volume shrinkage effect state of the currently prepared silicon carbide slurry. Specifically, during the pre-drying process of the silicon carbide slurry, visible light vision recognition and absorption spectrum recognition are carried out on it to obtain the volume change data and solvent content change data of the silicon carbide slurry during the pre-drying process; among them, the above volume change data can be obtained by taking visible light images of the silicon carbide slurry and contour recognition to determine the external contour characteristics of the silicon carbide slurry itself, so as to obtain the volume size change data (i.e., volume reduction change data) of the silicon carbide slurry in different dimensions. Please refer to Figure 2 , the silicon carbide slurry will shrink both horizontally and vertically, and the horizontal shrinkage rate is basically higher than the vertical shrinkage rate; in addition, the higher the original solvent volume ratio of the silicon carbide slurry, the higher its shrinkage rate (horizontal shrinkage rate and vertical shrinkage rate).

[0030] Solvents such as ionic water and / or absolute ethanol inside the silicon carbide slurry have different characteristic absorption wavelengths. The higher the content of deionized water and / or absolute ethanol inside the silicon carbide slurry, the higher the absorption intensity of the light with the corresponding characteristic absorption wavelength. By carrying out absorption spectrum recognition and analysis on the silicon carbide slurry, the solvent content change data inside the silicon carbide slurry can be obtained. The reduction of the solvent content inside the silicon carbide slurry causes volume reduction. By correlating and analyzing the volume size change data and the internal solvent content change data of the silicon carbide slurry, the correlation relationship between the volume reduction rate and the solvent content reduction rate of the silicon carbide slurry during the pre-drying process can be obtained. The above correlation relationship can be, but is not limited to, the volume reduction ratio of the silicon carbide slurry when the internal solvent content ratio of the silicon carbide slurry decreases by one percentage point during the pre-drying process (i.e., the deformation characteristics of the silicon carbide slurry during the pre-drying process), so as to quantitatively calibrate the volume reduction degree of the silicon carbide slurry due to solvent volatilization during the pre-drying process, providing a reliable reference for determining the required volume for molding the silicon carbide slurry subsequently.

[0031] The silicon carbide ceramic sealing component has a corresponding allowable deviation in external shape and volume in practical applications, that is, even if there is an up-and-down floating deviation between the actual volume of the silicon carbide ceramic sealing component and the expected volume, the silicon carbide ceramic sealing component can still be considered a qualified product and can be directly applied to the sealing scenario. In order to make the green body after molding pass through the sintering process so that the actual volume of the obtained silicon carbide ceramic sealing component matches the above-mentioned allowable deviation in external shape and volume, the volume of the silicon carbide slurry that has completed pre-drying required for molding can be determined according to the deformation characteristics of the above-mentioned silicon carbide slurry during pre-drying and the allowable range of volume deviation between the expected volume and the actual volume of the sealing component. This can accurately determine the volume of the silicon carbide slurry that has completed pre-drying required for molding by fully considering the volume shrinkage effect of the silicon carbide slurry and the tolerance range of the external shape and volume of the sealing component, and effectively reduce the probability of forming defective products due to excessive shrinkage of the green body after passing through the sintering process.

[0032] S2: Obtain the internal structure change characteristics of the green body during sintering. Based on the internal structure change characteristics, identify the sintering abnormal area of the green body and adjust the sintering operation parameters of the sintering abnormal area.

[0033] Further, in S2, obtaining the internal structure change characteristics of the green body during sintering, identifying the sintering abnormal area of the green body based on the internal structure change characteristics, and adjusting the sintering operation parameters of the sintering abnormal area specifically include: Perform thermal infrared vision recognition on the green body during sintering to obtain the change characteristics of the microporous structure inside the green body; among them, the change characteristics of the microporous structure include the change characteristics of the micropore size and the change characteristics of the micropore distribution density inside the green body during sintering; Based on the change characteristics of the microporous structure, estimate the change trend of the occupied range of micropores inside the green body during sintering, and thus identify the sintering abnormal area of the green body; based on the micropore size and micropore distribution density of the sintering abnormal area, adjust the sintering heat flow temperature and coverage area output to the sintering abnormal area.

[0034] Lubricity issues also need to be considered during the use of silicon carbide ceramic sealing components. In order to improve the lubrication performance of silicon carbide ceramic seals, lubricants are usually added to the silicon carbide ceramic sealing components. The microporous structure of the silicon carbide ceramic sealing component itself is conducive to adsorbing lubricants, enabling the lubricants to penetrate evenly inside the silicon carbide ceramic sealing component to form good lubrication performance. Generally speaking, the more and more evenly distributed the microporous structure of the silicon carbide ceramic sealing component is, the more and more evenly the lubricants penetrate and adhere to the silicon carbide ceramic sealing component. The number, size, and distribution density of the microporous structure of the silicon carbide ceramic sealing component depend on the heating degree of different areas of the green body during sintering. By adjusting the heating state of the green body during sintering, the physical state of the microporous structure of the sealing component can be changed.

[0035] The high-temperature environment during the sintering of the green body causes stress to form inside the green body. These changes match the internal structure, resulting in subtle changes in the tightness of the material combination inside the green body, thus forming a microporous structure. Please refer to Figure 3 , where (a)-(f) in the figure respectively correspond to the thermal infrared images of the green body at sintering heating temperatures of 400 °C, 500 °C, 600 °C, 650 °C, 700 °C, and 750 °C. Please refer to Figure 4 , where (a)-(f) in the figure are respectively the internal stress distribution diagrams of the green body converted according to the corresponding (a)-(f) in Figure 3 . By performing thermal infrared photography and internal stress distribution analysis on the green body during sintering, the microporous structure formed inside the green body during sintering can be accurately identified. Specifically, first perform thermal infrared photography on the green body during sintering to obtain the thermal infrared image of the green body (i.e., Figure 3 ); then analyze the thermal infrared image to obtain the magnitude of the internal stress distribution of the green body (i.e., Figure 4 ), determine the change characteristics of the micropore size and the change characteristics of the micropore distribution density inside the green body. Subsequently, determine the change characteristics of the micropore size and the change characteristics of the micropore distribution density inside the green body, and quantitatively determine the change of the micropore size inside the green body during sintering and the change of the number of micropores distributed per unit area, providing a reliable basis for adjusting the heating state of the green body during sintering.

[0036] The silicon carbide material inside the green body will be converted into a molten state during sintering. If the sintering heating temperature of a certain area inside the green body is higher, the silicon carbide material in the corresponding area will be fused more tightly under the action of stress. The microporous structure in the corresponding area will show a shrinking trend in terms of size and quantity, and the structure in the corresponding area will be more compact, and a uniform microporous structure distribution cannot be formed. Through the above analysis, it can be seen that changing the sintering heating temperature of the green body during sintering will form different thermal stress effects inside the green body, and different thermal stress effects will affect the change trend of the microporous structure inside the green body in terms of size and quantity. Thus, by Figure 4The size distribution of the internal stress formed by the green body at different sintering heating temperatures can be used to estimate the change characteristics of the micropore size and the change characteristics of the micropore distribution density inside the green body during sintering, so as to obtain the change trend of the occupied range of the micropores inside the green body during sintering. Generally speaking, the higher the sintering heating temperature of a certain area inside the green body during sintering, the greater the corresponding internal stress formed. At this time, the micropore size in this area will become smaller and the micropore distribution density will also become smaller (that is, the number of micropores in the unit volume space will also become smaller); conversely, the micropore size in this area will become larger and the micropore distribution density will also become larger (that is, the number of micropores in the unit volume space will also become larger). If the above-mentioned change trend of the occupied range of the micropores indicates that the average micropore size and / or the average micropore distribution density in a certain area of the green body show a decreasing trend, the corresponding area will be determined as the sintering abnormal area of the green body; otherwise, the corresponding area will not be determined as the sintering abnormal area of the green body. Then, based on the micropore size and the micropore distribution density in the sintering abnormal area, within the allowable range of the sintering temperature (that is, within the temperature range that ensures the normal progress of sintering), the temperature and the coverage area of the sintering heat flow output to the sintering abnormal area are adaptively reduced to effectively inhibit the shrinking trend of the micropores in the sintering abnormal area, so that the sintering abnormal area maintains a sufficient number and size of micropore structures.

[0037] S3: Perform thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component; based on the global cooling characteristics, estimate the internal stress difference characteristics between different parts inside the sealing component, and adjust the active cooling operation parameters for the sealing component accordingly.

[0038] Furthermore, in S3, performing thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component specifically includes: Performing thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein, the global cooling characteristics refer to the cooling rate characteristics of all parts inside the sealing component respectively.

[0039] After the green body undergoes the sintering process, it is formed and solidified into a sealing component. At this time, the entire sealing component is in a high-temperature state and needs to be cooled down for a certain period of time to obtain the final product. The cooling rate and uniformity of the sealing component directly affect the internal stress distribution of the sealing component. For a sealing component with a regular shape, only by ensuring that the entire sealing component is in a stable temperature environment can uniform cooling of all areas below the sealing component be achieved; however, for an irregularly shaped sealing component, the thickness of some parts of the sealing component in a certain direction is greater than that of other parts. Under the same natural cooling conditions, the natural cooling rate of the thicker parts is lower than that of the thinner parts. As the cooling of the sealing component progresses, the temperature difference between the thicker parts and the thinner parts becomes larger, and correspondingly, the stress difference between the thicker parts and the thinner parts also becomes larger. Please refer to Figure 5 , there is a corresponding relationship between the flexural stress and compressive stress formed in the parts of the sealing component and the temperature of the component. If the temperature difference between parts with different thicknesses during the cooling process is not suppressed in a timely manner, it will lead to the occurrence of internal stress anisotropy events between parts with different thicknesses (that is, the stress difference between the flexural stress or compressive stress between parts with different thicknesses exceeds the preset difference threshold within the corresponding spatial range), which is likely to cause fractures between parts with different thicknesses. In order to accurately suppress the continuous expansion of the stress difference between parts with different thicknesses in a timely manner, it is necessary to globally identify the cooling state of the sintered sealing component to obtain the cooling situation of each part under the sealing component globally. Specifically, the sintered sealing component can be dynamically identified by thermal infrared to obtain the change characteristics of the cooling rate of each part of the sealing component under the current natural cooling conditions (that is, the temperature drop value of each part per unit time), so as to accelerate the heat dissipation efficiency of some parts with slower cooling in the follow-up and achieve uniform cooling of all parts as much as possible.

[0040] Furthermore, in S3, based on the global cooling characteristics, estimate the internal stress difference characteristics between different parts of the sealing component, and adjust the active cooling operation parameters of the sealing component accordingly. Specifically: Based on the global cooling characteristics, determine the change difference in the cooling rate between two adjacent parts with different thicknesses within the sealing component; based on the change difference in the cooling rate, estimate the internal stress difference characteristics between two adjacent parts with different thicknesses; among them, the internal stress difference characteristics include the internal stress magnitude and direction difference characteristics between two adjacent parts with different thicknesses; Based on the internal stress difference characteristics between two adjacent parts with different thicknesses, determine whether internal stress anisotropy events will occur between two adjacent parts with different thicknesses; when internal stress anisotropy events occur, adjust the flow rate and the air flow delivery coverage area of the active cooling air flow delivered to two adjacent parts with different thicknesses.

[0041] As can be seen from the above analysis, if there is a large difference in the cooling efficiency between two different parts inside the sealing component, it will lead to a large difference in the internal stress between the above two parts. Especially for two different adjacent parts in terms of position, if the internal stress difference between the two adjacent different parts exceeds the upper limit of the internal stress difference that silicon carbide ceramics can withstand, it will increase the probability of fracture at the connection of the two adjacent different parts. In order to suppress the risk of fracture caused by large internal stress differences within the entire sealing component, based on the global cooling characteristics of the sealing component, the change difference in the cooling rate between any two adjacent parts with different thicknesses inside the sealing component is determined, so as to estimate the internal stress magnitude and direction deviation characteristics between any two adjacent parts with different thicknesses, that is, the internal stress magnitude difference value and the internal stress direction angle difference value between any two adjacent parts with different thicknesses, thereby determining whether an internal stress anisotropy event will occur between two adjacent parts with different thicknesses. If the stress difference within the corresponding spatial angle range of the internal stress between two adjacent parts with different thicknesses exceeds the preset difference threshold, it is determined that an internal stress anisotropy event has occurred; otherwise, it is determined that no internal stress anisotropy event has occurred. And when an internal stress anisotropy event occurs, the part with a slower cooling rate among the two adjacent parts with different thicknesses is calibrated, so as to increase the cooling efficiency of the above part with a slower cooling rate; specifically, the flow rate and the air flow delivery coverage area of the active cooling air flow delivered to the above part with a slower cooling rate can be increased, effectively suppressing the difference in the cooling efficiency between two adjacent parts with different thicknesses and improving the uniformity of the internal stress distribution of the sealing component.

[0042] Please refer to Figure 6 as shown, the present invention provides a production and molding system for a silicon carbide ceramic sealing component, and the system includes the following modules: A deformation recognition module, which is used to obtain the deformation characteristics of silicon carbide slurry during pre-drying; A molding control module, which is used to perform molding on the silicon carbide slurry that has completed pre-drying based on the deformation characteristics and the outer shape tolerance characteristics of the sealing component to obtain a green body; A structure change recognition module, which is used to obtain the internal structure change characteristics of the green body during sintering; A sintering adjustment module, which is used to identify the sintering abnormal area of the green body based on the internal structure change characteristics and adjust the sintering operation parameters of the sintering abnormal area; A thermal recognition module, which is used to perform thermal recognition on the sintered sealing component to obtain the global cooling characteristics of the sealing component; A cooling adjustment module, which is used to estimate the internal stress difference characteristics between different parts inside the sealing component based on the global cooling characteristics, and thereby adjust the active cooling operation parameters of the sealing component.

[0043] Furthermore, the deformation recognition module is used to obtain the deformation characteristics of the silicon carbide slurry during pre-drying, specifically as follows: Perform visible light vision recognition and absorption spectrum recognition on the silicon carbide slurry during pre-drying to obtain the volume change data and solvent content change data of the silicon carbide slurry during pre-drying; based on the volume change data and solvent content change data, obtain the correlation characteristics between the volume shrinkage rate and the solvent content reduction rate of the silicon carbide slurry during pre-drying, and use this as the deformation characteristics of the silicon carbide slurry during pre-drying; The molding control module is used to perform molding on the pre-dried silicon carbide slurry based on the deformation characteristics and the external tolerance characteristics of the sealing component to obtain a green body, specifically as follows: Based on the deformation characteristics and the external tolerance characteristics of the sealing component, determine the volume of the pre-dried silicon carbide slurry required for molding, and use this to mold the corresponding volume of the silicon carbide slurry into a green body; wherein, the external tolerance characteristics of the sealing component refer to the allowable range of volume deviation between the desired volume and the actual volume of the sealing component.

[0044] Furthermore, the structure change recognition module is used to obtain the internal structure change characteristics of the green body during sintering, specifically as follows: Perform thermal infrared vision recognition on the green body during sintering to obtain the microporous structure change characteristics inside the green body; wherein, the microporous structure change characteristics include the micropore size change characteristics and the micropore distribution density change characteristics inside the green body during sintering; The sintering adjustment module is used to identify the sintering abnormal area of the green body based on the internal structure change characteristics and adjust the sintering operation parameters of the sintering abnormal area, specifically as follows: Based on the microporous structure change characteristics, estimate the change trend of the micropore occupancy range inside the green body during sintering, and use this to identify the sintering abnormal area of the green body; based on the micropore size and micropore distribution density of the sintering abnormal area, adjust the sintering heat flow temperature and coverage area output to the sintering abnormal area.

[0045] Furthermore, the thermal recognition module is used to perform thermal recognition on the sintered sealing component to obtain the global cooling characteristics of the sealing component, specifically as follows: Perform thermal recognition on the sintered sealing component to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein, the global cooling characteristics refer to the cooling rate characteristics of all parts inside the sealing component.

[0046] Furthermore, the cooling adjustment module is used to estimate the internal stress difference characteristics between different parts inside the sealing component based on the global cooling characteristics, and use this to adjust the active cooling operation parameters of the sealing component, specifically as follows: Based on the global cooling characteristics, determine the difference in the change rate of cooling between two adjacent parts with different thicknesses within the sealing component; based on the difference in the change rate of cooling, estimate the characteristics of the internal stress difference between two adjacent parts with different thicknesses; wherein, the characteristics of the internal stress difference include the magnitude and direction difference characteristics of the internal stress between two adjacent parts with different thicknesses. Based on the characteristics of the internal stress difference between two adjacent parts with different thicknesses, determine whether an internal stress anisotropy event will occur between the two adjacent parts with different thicknesses; when an internal stress anisotropy event occurs, adjust the flow rate and the airflow delivery coverage area of the active cooling airflow delivered to the two adjacent parts with different thicknesses.

[0047] The production and molding system of the silicon carbide ceramic sealing component of the present invention corresponds to the operation and effect of the above-mentioned production and molding method of the silicon carbide ceramic sealing component, and the production and molding system of the silicon carbide ceramic sealing component will not be described repeatedly here.

[0048] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of adding a necessary general hardware platform, and of course, it can also be implemented by a combination of hardware and software. Based on such an understanding, the above technical solution, in essence, or the part that contributes to the prior art can be embodied in the form of a computer product. The present invention can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0049] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them, and other embodiments can also be adopted; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing and molding a silicon carbide ceramic sealing component, characterized in that: The method comprises the following steps: S1: obtaining deformation characteristics of the silicon carbide slurry during pre-drying, and based on the deformation characteristics and the external shape difference characteristics of the sealing component, performing compression molding on the pre-dried silicon carbide slurry to obtain a green body; S2: acquiring internal structural change characteristics of the green body during sintering, identifying abnormal sintering areas of the green body based on the internal structural change characteristics, and adjusting sintering operation parameters of the abnormal sintering areas; S3: Performing thermal identification on the sintered sealing component to obtain the global cooling characteristics of the sealing component; based on the global cooling characteristics, estimating the internal stress difference characteristics between different parts of the sealing component, thereby adjusting the active cooling operation parameters of the sealing component.

2. The method according to claim 1, characterized in that In S1, the deformation characteristics of the silicon carbide slurry during pre-drying are obtained, and based on the deformation characteristics and the external shape difference characteristics of the sealing component, the pre-dried silicon carbide slurry is compression molded to obtain a green body, specifically: Performing visible light visual identification and absorption spectrum identification on the silicon carbide slurry during pre-drying to obtain volume change data and solvent content change data of the silicon carbide slurry during pre-drying; based on the volume change data and the solvent content change data, obtaining a correlation feature between a volume reduction rate and a solvent content reduction rate of the silicon carbide slurry during pre-drying, and using this as a deformation feature of the silicon carbide slurry during pre-drying; Based on the deformation characteristics and the external shape difference characteristics of the sealing component, the volume of the pre-dried silicon carbide slurry required for compression molding is determined, so that the corresponding volume of the silicon carbide slurry is compression molded into a blank; wherein the external shape difference characteristics of the sealing component refer to the allowable range of volume deviation between the expected volume and the actual volume of the sealing component.

3. The method according to claim 1, characterized in that: In S2, the internal structural change characteristics of the green body during sintering are obtained, and based on the internal structural change characteristics, the abnormal sintering area of ​​the green body is identified, and the sintering operation parameters of the abnormal sintering area are adjusted, specifically: Performing thermal infrared visual identification on the green body during sintering to obtain the micropore structure change characteristics inside the green body; wherein the micropore structure change characteristics include the micropore size change characteristics and micropore distribution density change characteristics inside the green body during sintering; Based on the characteristics of the changes in the micropore structure, the changing trend of the micropore occupancy range inside the green body during sintering is estimated to identify the abnormal sintering area of ​​the green body; based on the micropore size and micropore distribution density of the abnormal sintering area, the sintering heat flow temperature and coverage area output to the abnormal sintering area are adjusted.

4. The method according to claim 1, characterized in that: In S3, thermal identification is performed on the sealing component obtained by sintering to obtain the global temperature drop characteristics of the sealing component, specifically: The sealing component obtained by sintering is subjected to thermal identification to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein the global cooling characteristics refer to the cooling speed characteristics of all parts of the sealing component.

5. The method according to claim 4, characterized in that In S3, based on the global cooling characteristics, the internal stress difference characteristics between different parts of the sealing component are estimated, so as to adjust the active cooling operation parameters of the sealing component, specifically: Based on the global cooling characteristics, determining the difference in the change in the cooling rate between two adjacent parts with different thicknesses in the sealing component; based on the difference in the cooling rate, estimating the difference characteristics of the internal stress between two adjacent parts with different thicknesses; wherein the difference characteristics of the internal stress include the difference characteristics of the magnitude and direction of the internal stress between two adjacent parts with different thicknesses; Based on the internal stress difference characteristics between two adjacent parts with different thicknesses, it is judged whether an internal stress anisotropy event will occur between the two adjacent parts with different thicknesses; when an internal stress anisotropy event occurs, the active cooling airflow delivery flow rate and airflow delivery coverage area of ​​the two adjacent parts with different thicknesses are adjusted.

6. A production and molding system for silicon carbide ceramic sealing components, characterized in that: The system includes the following modules: A deformation recognition module, used to obtain the deformation characteristics of silicon carbide slurry during pre-drying; A compression molding control module, used for compression molding the pre-dried silicon carbide slurry based on the deformation characteristics and the external shape difference characteristics of the sealing component to obtain a green body; A structural change identification module, used to obtain the internal structural change characteristics of the green body during sintering; A sintering adjustment module, used to identify the abnormal sintering area of ​​the green body based on the internal structure change characteristics, and adjust the sintering operation parameters of the abnormal sintering area; A thermal identification module, used to perform thermal identification on the sealing component obtained by sintering, and obtain the global temperature reduction characteristics of the sealing component; The temperature reduction adjustment module is used to estimate the internal stress difference characteristics between different parts of the sealing component based on the global temperature reduction characteristics, so as to adjust the active temperature reduction operation parameters of the sealing component.

7. The system according to claim 6, characterized in that The deformation recognition module is used to obtain the deformation characteristics of the silicon carbide slurry during pre-drying, specifically: Performing visible light visual identification and absorption spectrum identification on the silicon carbide slurry during pre-drying to obtain volume change data and solvent content change data of the silicon carbide slurry during pre-drying; based on the volume change data and the solvent content change data, obtaining a correlation feature between a volume reduction rate and a solvent content reduction rate of the silicon carbide slurry during pre-drying, and using this as a deformation feature of the silicon carbide slurry during pre-drying; The compression molding control module is used to compression mold the pre-dried silicon carbide slurry based on the deformation characteristics and the external shape difference characteristics of the sealing component to obtain a green body, specifically: Based on the deformation characteristics and the external shape difference characteristics of the sealing component, the volume of the pre-dried silicon carbide slurry required for compression molding is determined, so that the corresponding volume of the silicon carbide slurry is compression molded into a blank; wherein the external shape difference characteristics of the sealing component refer to the allowable range of volume deviation between the expected volume and the actual volume of the sealing component.

8. The system according to claim 6, characterized in that The structural change identification module is used to obtain the internal structural change characteristics of the green body during sintering, specifically: Performing thermal infrared visual identification on the green body during sintering to obtain the micropore structure change characteristics inside the green body; wherein the micropore structure change characteristics include the micropore size change characteristics and micropore distribution density change characteristics inside the green body during sintering; The sintering adjustment module is used to identify the abnormal sintering area of ​​the green body based on the internal structure change characteristics, and adjust the sintering operation parameters of the abnormal sintering area, specifically: Based on the characteristics of the changes in the micropore structure, the changing trend of the micropore occupancy range inside the green body during sintering is estimated to identify the abnormal sintering area of ​​the green body; based on the micropore size and micropore distribution density of the abnormal sintering area, the sintering heat flow temperature and coverage area output to the abnormal sintering area are adjusted.

9. The system according to claim 6, characterized in that The thermal identification module is used to perform thermal identification on the sealing component obtained by sintering, and obtain the global temperature reduction characteristics of the sealing component, specifically: The sealing component obtained by sintering is subjected to thermal identification to obtain the global cooling characteristics of the sealing component under natural cooling conditions; wherein the global cooling characteristics refer to the cooling speed characteristics of all parts of the sealing component.

10. The system according to claim 9, characterized in that The temperature reduction adjustment module is used to estimate the internal stress difference characteristics between different parts of the sealing component based on the global temperature reduction characteristics, so as to adjust the active temperature reduction operation parameters of the sealing component, specifically: Based on the global cooling characteristics, determining the difference in the change in the cooling rate between two adjacent parts with different thicknesses in the sealing component; based on the difference in the cooling rate, estimating the difference characteristics of the internal stress between two adjacent parts with different thicknesses; wherein the difference characteristics of the internal stress include the difference characteristics of the magnitude and direction of the internal stress between two adjacent parts with different thicknesses; Based on the internal stress difference characteristics between two adjacent parts with different thicknesses, it is judged whether an internal stress anisotropy event will occur between the two adjacent parts with different thicknesses; when an internal stress anisotropy event occurs, the active cooling airflow delivery flow rate and airflow delivery coverage area of ​​the two adjacent parts with different thicknesses are adjusted.

Images