A ceramic powder molding machine and method for preparing a ceramic powder having a columnar skeleton structure

Abstract

The application discloses a ceramic powder forming machine and method for preparing a ceramic powder with a columnar skeleton structure, and mainly improves the shear strength of a layered ceramic material and solves the problems of multiple processes and low efficiency existing in a method for constructing a layered ceramic structure. In the layered ceramic, a columnar skeleton is constructed, the skeleton can not only prevent the layered structure from cracking, but also share the force and impact received by the layered material, and the shear strength of the layered ceramic material is improved. Meanwhile, a device required for preparing the structure is designed, the device is mainly composed of a workbench and a mold, the skeleton powder is pushed into by cooperation of upper and lower pressing heads, collapse of the matrix powder can be avoided, the integrity of the structure is ensured, the device can be replaced with accessories according to a design scheme, different design structures can be adapted, the preparation process is simple, and the preparation efficiency can be improved.

Description

Technical Field

[0001] This invention relates to powder metallurgy equipment, specifically to a ceramic powder forming machine for preparing ceramic powder with a columnar skeleton structure and a method for preparing ceramic powder with a columnar skeleton structure, which solves the problems of multiple steps and low efficiency in existing methods for constructing layered ceramic structures, and improves the shear strength of layered ceramic materials. Background Technology

[0002] Layered ceramics often employ a conventional flat-layer structure. Due to the differences between the materials in each layer, their interfacial bonding strength is generally low. This results in insufficient shear strength parallel to the layer direction, making them prone to micro-cracks or even interface splitting under complex working conditions. Consequently, this affects their stability and reliability in practical applications.

[0003] In recent years, the shear strength of layered ceramics has been primarily improved by altering their structure. Methods for constructing layered ceramic structures mainly include: molding interface microstructures, bidirectional cryogenic infiltration, casting sheet perforation, ceramic 3D printing, and cold-press laser etching. While there are many methods for constructing layered ceramic structures, each has its limitations. The molding interface microstructure method has limitations on the single-layer thickness of layered ceramics due to the uneven structure of the interface, and requires each layer to be molded separately, resulting in low preparation efficiency. The two-way cryopreservation method requires the mixing of organic solvents into the slurry during the preparation of three-dimensional layered ceramic skeletons, which will result in organic impurities in the finished product. The tape casting method involves overlapping and pressing perforated interface tapes with flat substrate tapes to form a discontinuous bonding structure of the substrate layer, but it is difficult to ensure the uniformity of the pore filling during the preparation process, resulting in poor interface flatness, and the tape casting method will leave organic residues in the product. Ceramic 3D printing method has high requirements for material flowability and curing performance, which limits the diversity of material composition design. The cold pressing laser etching method requires cold pressing and laser etching of the substrate layer separately, and then alternately pressing it with the interface powder in a mold, which involves many processes and is costly. Summary of the Invention

[0004] To improve the shear strength of layered ceramic materials and solve the problems of multiple steps and low efficiency in existing methods for constructing layered ceramic structures, this invention designs a ceramic powder forming machine and method for preparing a columnar skeleton structure, which can produce a novel layered ceramic material with a columnar skeleton structure.

[0005] This invention is achieved using the following technical solution: a ceramic powder forming machine for preparing a columnar skeleton structure, comprising a worktable with a positioning groove on one side and a positioning base confined within the positioning groove, the positioning base having a groove on its upper surface and multiple through holes on its bottom surface; a cylindrical graphite mold with an outer diameter the same as the inner diameter of the positioning base groove is pressed into the positioning base groove; a pad with through holes is placed inside the graphite mold; and an upper pressure head guide cylinder with an outer diameter the same as the inner diameter of the graphite mold, the upper pressure head guide cylinder having a through hole at its bottom; an upper pressure head is placed inside the upper pressure head guide cylinder. The lower part has a columnar structure that matches the through hole of the upper pressure head guide cylinder, and the depth of the through hole is the same as the length of the columnar structure of the upper pressure head; the position and number of through holes on the upper pressure head guide cylinder, positioning base, and pad block correspond one-to-one; the top of the upper pressure head guide cylinder is connected to an upper pressure head cover located outside the top port of the graphite mold; the upper pressure head cover has a central hole; the top of the upper pressure head is connected to an extrusion handle that extends out of the upper pressure head cover; a lifting platform is provided below the worktable, and a lower pressure head with a columnar structure matching the through hole of the positioning base is placed on the lifting platform. The columnar structure of the lower pressure head passes through the through hole of the positioning base and extends into the interior of the graphite mold.

[0006] To achieve a columnar skeleton structure, this invention, taking a cylindrical skeleton and a uniformly distributed cylindrical structure as examples, designs a corresponding mold device. The columnar structure of the lower pressure head passes through a hole in the positioning base that matches its structure and extends into the interior of the graphite mold. A pad matching the lower pressure head is placed at the bottom of the graphite mold, separating the ceramic blank composed of matrix powder and skeleton powder from the positioning base. A lifting platform is placed under the lower pressure head, serving to support the lower pressure head and adjust its height. The upper pressure head has the same columnar structure as the lower pressure head. The bottom of the upper pressure head guide cylinder has a through hole that matches the lower pressure head. The depth of the through hole is the same as the length of the columnar structure of the upper pressure head, ensuring that the surface of the matrix powder and the skeleton powder are flush when the upper pressure head can no longer descend. The outer diameter of the upper pressure head guide cylinder is the same as the inner diameter of the graphite mold to accommodate the orientation of the lower pressure head structure within the graphite mold. The upper pressure head, upper pressure head guide cylinder, lower pressure head, base, and pad can be replaced according to the design scheme.

[0007] Furthermore, the top of the upper pressure head guide cylinder has an external thread, and the inner wall of the center hole of the upper pressure head cover has an internal thread. The upper pressure head guide cylinder and the upper pressure head cover are connected through the internal and external threads. The upper pressure head cover facilitates pressure application when compacting powder, and the spiral structure makes it easy to replace the upper pressure head guide cylinder according to the design.

[0008] The top center of the upper pressure head is connected to the extrusion handle via a thread; the spiral structure allows for easy replacement of different upper pressure heads according to the design scheme.

[0009] The present invention discloses a method for preparing ceramic powder with a columnar skeleton structure, comprising the following steps: pushing a positioning base into the positioning groove of a worktable; pressing a graphite mold tightly into the groove of the positioning base; placing a lower pressure head on a lifting platform; adjusting the lifting platform to position the lower pressure head at a suitable height; placing a pad block into the graphite mold; pouring different layers of matrix powder into the graphite mold in layers; after each layer of powder is poured, compacting and flattening it using the upper pressure head guide tube and the upper pressure head cover before pouring another layer of powder; after all layers have completed the compaction step, placing the upper pressure head guide tube into the graphite mold; and adjusting the height of the lower pressure head so that its columnar structure partially submerges the through hole of the upper pressure head guide tube. The skeleton powder is poured into the upper pressure head guide cylinder. The extrusion handle is pressed firmly, and the skeleton powder is compacted by the upper pressure head. At this time, the wall of the upper pressure head guide cylinder and the upper and lower pressure heads that extend into its through hole form a closed space. By coordinating the descent height of the upper and lower pressure heads, the skeleton powder is slowly pushed into the matrix powder. The coordination of the upper and lower pressure heads and the slow descent speed can prevent the collapse of the matrix powder. Until the upper pressure head can no longer descend, the extrusion handle, along with the upper pressure head and the upper pressure head guide cylinder, is removed. A solid pad is placed and compacted. The remaining mold structure is pushed out using the positioning base. The mold is inverted, and the lower pressure head and positioning base are removed. The pad is gently removed and replaced with a solid pad to complete the preparation of the green blank.

[0010] The apparatus described in this invention can be used to prepare ceramic blanks with a columnar skeleton structure. Ceramic materials with a columnar skeleton structure can be obtained through a sintering process. The columnar skeleton penetrates the bonding surface of the layered ceramic, which can prevent the layered material from cracking at the interface. At the same time, under complex working conditions, it can share the external force and impact on the matrix powder, improve the shear strength of the layered ceramic material, and improve the reliability of the layered ceramic material.

[0011] This invention designs a molding machine for preparing ceramic powder with a columnar skeleton structure. The mold in this molding machine has replaceable parts according to the design scheme to adapt to different design structures. The method of pushing the skeleton powder in by the cooperation of the upper and lower pressure heads ensures the integrity of the powder structure and prevents powder collapse. Simultaneously, the novel layered ceramic structure with a columnar skeleton proposed in this invention can improve the shear strength of layered ceramics. The preparation process is simple, improving preparation efficiency. Furthermore, the entire process does not require the introduction of organic solvents, which helps to ensure the purity of the green body. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the molding machine described in this invention.

[0013] In the figure: 1-Extrusion handle, 2-Upper pressure head cover, 3-Upper pressure head guide cylinder, 4-Upper pressure head, 5-Positioning base, 6-Workbench, 7-Lower pressure head, 8-Lifting platform, 9-Padded block, 10-Matrix powder, 11-Skeleton powder, 12-Graphite mold.

[0014] Figure 2 for Figure 1 A schematic diagram of the upper and middle pressure head guide cylinder. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0016] like Figure 1 As shown, the columnar skeleton forming machine designed in this invention mainly includes a worktable and a mold. It includes a worktable 6 with a positioning groove on one side, a positioning base 5 pushed into the worktable 6 along the groove, and a graphite mold 12 pressed tightly into the groove of the base 5, the outer diameter of which is the same as the inner diameter of the circular groove of the positioning base 5. A lower pressure head 7, designed with the required columnar structure, passes through a hole in the positioning base 5 that matches its structure and extends into the interior of the graphite mold 12. A pad 9 matching the lower pressure head 7 is placed at the bottom of the graphite mold 12, separating the ceramic blank composed of the matrix powder 10 and the skeleton powder 11 from the positioning base 5. A lifting platform 8 is placed below the lower pressure head 7, serving to support the lower pressure head 7 and adjust its height. An upper pressure head 4 and a lower... The pressure head 7 has the same columnar structure and is connected to the extrusion handle 1 via a spiral structure. The spiral structure allows for easy replacement of different upper pressure heads 4 according to the design scheme. The bottom of the upper pressure head guide cylinder 3 has a through hole that matches the lower pressure head 7. The depth of the through hole is the same as the length of the columnar structure of the upper pressure head 4, ensuring that the surface of the matrix powder 10 and the skeleton powder 11 is flush when the upper pressure head 4 can no longer descend. The outer diameter of the upper pressure head guide cylinder 3 is the same as the inner diameter of the graphite mold 12 to accommodate the orientation of the lower pressure head 7 structure when placed into the graphite mold 12. The upper end of the upper pressure head guide cylinder 3 of the upper pressure head 4 is screwed into the upper pressure head cover 2 via a spiral structure. The upper pressure head cover 2 facilitates pressure application when compacting the powder, and the spiral structure allows for easy replacement of the upper pressure head guide cylinder 3 according to the design. The lower columnar structure of the upper pressure head 4 is connected to the lower surface of a base plate.

[0017] There are various structures available for the lifting platform; in this embodiment, a scissor lift platform is selected.

[0018] During operation, push the positioning base 5 into the worktable 6, install the graphite mold 12, place the lower pressure head 7 on the lifting platform 8, rotate the knob of the lifting platform 8 to bring the lower pressure head 7 to a suitable height, and place the pad block 9. Pour different layers of matrix powder 10 into the graphite mold 12 in layers. After each layer of powder is poured in, compact it using the upper pressure head guide cylinder 3 and the upper pressure head cover 2 before pouring in another layer of powder. After all layers are compacted, place the upper pressure head guide cylinder 3 and the upper pressure head cover 2 into the graphite mold 12. Adjust the height of the lower pressure head 7 so that its columnar structure is partially submerged in the through hole of the upper pressure head guide cylinder 3, pour the skeleton powder 11 into the upper pressure head guide cylinder 3, and press the extruder firmly. Handle 1, compact skeleton powder 11. At this time, the through hole wall of the upper pressure head guide cylinder 3 and the upper pressure head 4 and lower pressure head 7 extending into its through hole form a closed space. By coordinating the descent height of the upper and lower pressure heads, the skeleton powder 11 is slowly pushed into the matrix powder 10. The coordination of the upper and lower pressure heads and the slow descent speed can prevent the collapse of the matrix powder 10. Until the upper pressure head 4 can no longer descend, the extrusion handle 1 along with the upper pressure head 2 and the upper pressure head guide cylinder 3 are taken out. A solid pad is placed and compacted. The remaining mold structure is pushed out using the positioning base 5. Invert it, take out the lower pressure head 7 and the positioning base 5, and gently take out the pad 9. Replace it with a solid pad to complete the preparation of the green blank.

[0019] In the above examples, the columnar structure is illustrated using a cylindrical shape with a uniform distribution. However, the cross-section of the columnar structure is not limited to a circle. It can also be changed to other structures such as ellipse or polygon according to the design. The distribution of the columnar structure is not limited to a uniform distribution. It can also be designed in different distribution forms according to the different requirements of the material's functional areas.

Claims

1. A molding machine for preparing ceramic powder with a columnar skeleton structure, characterized in that: The system includes a worktable (6) with a positioning groove on one side and a positioning base (5) located within the positioning groove. The positioning base (5) has a groove on its top and multiple through holes on its bottom surface. A cylindrical graphite mold (12) with the same outer diameter as the inner diameter of the groove is pressed into the positioning base (5). A pad (9) with through holes is placed inside the graphite mold (12). The system also includes an upper pressure head guide cylinder (3) with the same outer diameter as the inner diameter of the graphite mold (12). The bottom of the upper pressure head guide cylinder (3) has a through hole. An upper pressure head (4) is placed inside the upper pressure head guide cylinder (3). The lower part of the upper pressure head (4) has a columnar structure that matches the through hole of the upper pressure head guide cylinder (3), and the depth of the through hole is the same as the depth of the upper pressure head guide cylinder (3). The length of the columnar structure of the upper pressure head (4) is the same; the position and number of through holes on the upper pressure head guide cylinder (3), positioning base (5), and pad (9) correspond one to one; the top of the upper pressure head guide cylinder (3) is connected to the upper pressure head cover (2) located outside the top port of the graphite mold (12); the upper pressure head cover (2) has a central hole; the top of the upper pressure head (4) is connected to the extrusion handle (1) extending out of the upper pressure head cover (2); a lifting platform (8) is provided below the worktable (6), and a lower pressure head (7) with a columnar structure matching the through hole of the positioning base (5) is placed on the lifting platform (8). The columnar structure of the lower pressure head (7) passes through the through hole of the positioning base (5) and extends into the interior of the graphite mold (12).

2. The ceramic powder forming machine for preparing a columnar skeleton structure as described in claim 1, characterized in that: The top of the upper pressure head guide cylinder (3) has an external thread, and the inner wall of the center hole of the upper pressure head cover (2) has an internal thread. These two parts are connected by the internal and external threads.

3. The ceramic powder forming machine for preparing a columnar skeleton structure as described in claim 2, characterized in that: The top center of the upper pressure head (4) is connected to the extrusion handle (1) by a thread.

4. A ceramic powder forming machine for preparing a columnar skeleton structure as described in any one of claims 1-3, characterized in that: The cross-section of the columnar structure can be circular, elliptical, or polygonal; the columnar structure can be uniformly distributed or non-uniformly distributed.

5. A method for preparing ceramic powder with a columnar skeleton structure, comprising using a ceramic powder forming machine for preparing a columnar skeleton structure as described in any one of claims 1-4, characterized in that, The steps include: pushing the positioning base (5) into the positioning groove of the workbench (6), pressing the graphite mold (12) tightly into the groove of the positioning base (5), placing the lower pressure head (7) on the lifting platform (8), adjusting the lifting platform (8) to make the lower pressure head (7) at a suitable height, and placing the pad (9) into the graphite mold (12). The matrix powder (10) of different layers is poured into the graphite mold (12) in layers. After each layer of powder is poured, it is compacted and flattened by the upper pressure head guide cylinder (3) and the upper pressure head cover (2) before pouring another layer of powder. After all layers have been compacted, the upper pressure head guide cylinder (3) is placed in the graphite mold (12). The height of the lower pressure head (7) is adjusted so that its columnar structure is partially submerged in the through hole of the upper pressure head guide cylinder (3). The skeleton powder (11) is poured into the upper pressure head guide cylinder. In (3), press the extrusion handle (1) with force and compact the skeleton powder (11) through the upper pressure head (4). At this time, the wall of the through hole of the upper pressure head guide cylinder (3) and the upper pressure head (4) and lower pressure head (7) that extend into its through hole form a closed space. By coordinating the descent height of the upper and lower pressure heads, the skeleton powder (11) is slowly pushed into the matrix powder (10). The coordination of the upper and lower pressure heads and the slow descent speed can prevent the matrix powder (10) from collapsing. Until the upper pressure head (4) can no longer descend, take out the extrusion handle (1) along with the upper pressure head (4) and the upper pressure head guide cylinder (3), put in a solid pad and compact it, use the positioning base (5) to push out the remaining mold structure, invert it, take out the lower pressure head (7) and the positioning base (5), gently take out the pad (9), replace it with a solid pad, and complete the preparation of the blank.

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