Microwave hot-press sintering mold and method of use

Abstract

The application discloses a microwave hot-pressing sintering mold and a use method, relates to the field of microwave sintering devices, and comprises a hydraulic upper ejector rod, a hydraulic lower ejector rod and a hot-pressing heat preservation mold, wherein the hot-pressing heat preservation mold comprises a pressure head, a pressure column mold, a mold sleeve mold, an upper gasket and a lower gasket; the inner layer of the mold sleeve mold is a mold layer; the outer layer of the mold sleeve mold is a heat preservation layer; the mold layer has high compactness; and the heat preservation layer has a porous structure. The mold is made of a wave-transparent material, so that the mold does not disturb the electromagnetic field distribution in a microwave resonant cavity during use, the microwave can fully act on the sintered sample, the advantages of microwave sintering and hot-pressing sintering are combined, and ceramics which are difficult to sinter and densify can rapidly reach a relatively high density by using the device.

Description

Technical Field

[0001] This invention relates to the field of microwave sintering equipment, and more particularly to a microwave hot pressing sintering mold and its usage method. Background Technology

[0002] Microwave sintering, as a novel sintering method, has been widely used in the sintering preparation of various materials. Compared with traditional sintering methods, microwave sintering has the advantages of energy saving, high efficiency, fast heating rate, safety and no pollution. However, for ceramics that are difficult to sinter and densify, it is difficult to further improve the density of ceramics by relying solely on microwave sintering. However, by using pressure assistance, combined with the microwave plasma effect and electric field driven atomic diffusion mechanism that exist during microwave heating, it is expected that difficult-to-sinter ceramics can quickly achieve a higher density.

[0003] In the prior art, the utility model patent (ZL201621258273.7) involves a microwave hot pressing sintering device. However, the sintering mold in this patent uses silicon carbide absorbing material. The silicon carbide mold absorbs and converts microwave energy, allowing the temperature inside the furnace cavity to quickly reach the required temperature. This process is not fundamentally different from traditional heating sintering; both rely on thermal radiation and heat conduction to reach the preparation temperature. The aforementioned patent, due to the mold's absorption of electromagnetic waves, hinders the interaction between electromagnetic waves and the sample. In the utility model patent (ZL201420181983.9), the hot pressing mold is made of wave-transparent materials such as quartz and aluminum silicate fiber. However, it only involves the insulation layer and does not consider the mold's compressive strength. Insulation requires a porous structure, while compressive strength requires a high density. Insulation and compressive strength are contradictory. The aforementioned patent does not have a specific design for the mold's compressive strength, which limits the pressure the mold can withstand. Summary of the Invention

[0004] The purpose of this invention is to provide a microwave hot pressing sintering mold and its usage method. The mold layer has high compressive strength, the outer insulation layer of the mold has good heat preservation effect, and the mold is made of microwave-transparent material, which avoids the problem of disturbing the electromagnetic field distribution in the microwave resonant cavity.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] The present invention provides a microwave hot pressing sintering mold, comprising a hydraulic upper ejector rod, a hydraulic lower ejector rod, and a hot pressing heat preservation mold. The hot pressing heat preservation mold includes a pressure head, a pressure column mold, a mold sleeve mold, an upper gasket, and a lower gasket. The top and bottom of the mold sleeve mold are respectively provided with pressure heads, and the upper and lower surfaces of the two pressure heads are respectively connected to the hydraulic upper ejector rod and the hydraulic lower ejector rod.

[0007] The inner layer of the mold sleeve is a mold layer, and the outer layer of the mold sleeve is a heat insulation layer. The mold layer is embedded and connected inside the heat insulation layer. An upper gasket and a lower gasket are provided at the bottom of the interior of the mold layer. A material layer is located between the upper gasket and the lower gasket. The bottom of the pressure column mold extends into the interior of the mold layer and contacts the upper gasket. The top of the pressure column mold contacts the pressure head. The mold layer has high density, and the heat insulation layer has a porous structure.

[0008] Preferably, the upper hydraulic push rod and the lower hydraulic push rod are cylindrical, and the upper hydraulic push rod and the lower hydraulic push rod are made of alumina or quartz material.

[0009] Preferably, the pressure head, the pressure column mold, the upper gasket, and the lower gasket are all made of boron nitride ceramic material.

[0010] Preferably, the mold layer is made of boron nitride material, and the insulation layer is made of a combination of boron nitride and silicon oxide or aluminum silicate fiber material.

[0011] Preferably, the insulation layer is a porous ceramic or a high-temperature resistant aerogel.

[0012] The method of using a microwave hot pressing sintering mold as described above includes the following steps:

[0013] Step 1: Assemble the components in sequence. Place the pressure head on top of the hydraulic lower push rod, then place the insulation layer on top of the pressure head, place the mold layer into the insulation layer, then place the lower gasket at the bottom of the mold layer, put the material into the mold layer, place the upper gasket into the mold layer, and then place the pressure column mold into the mold layer and make contact with the upper gasket. Then, the hydraulic upper push rod moves downward to apply pressure to the pressure column mold to press the material, and at the same time, sintering is carried out in combination with microwave.

[0014] Step 2: After sintering, the hydraulic upper push rod drives the pressure column mold to move upward and away from the mold layer, thereby removing the pressure and taking the mold layer out of the insulation layer. The upper gasket, lower gasket and product are pushed out of the mold layer by the external pressure through the pressure column mold.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0016] This invention discloses a microwave hot-pressing sintering mold and its usage method. Since the hot-pressing sintering mold is made of microwave-transparent material, it avoids disturbing the electromagnetic field distribution within the microwave resonant cavity. Simultaneously, it allows electromagnetic waves to pass through the mold and interact with the sample. The microwave plasma effect and electric field-driven atomic diffusion mechanism present during microwave heating help promote the mass transfer process during sintering. Furthermore, this hot-pressing sintering mold incorporates a high-density mold layer, enabling it to withstand greater compressive strength. Through microwave sintering combined with pressure assistance, it is expected to rapidly achieve higher density for difficult-to-sinter ceramics. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of a microwave hot pressing sintering mold structure according to the present invention;

[0019] Figure 2 This is a microstructure diagram of the porous aerogel used in the insulation layer of this invention.

[0020] Explanation of reference numerals in the attached diagram: 1. Hydraulic upper ejector rod; 2. Press head; 3. Mold layer; 4. Insulation layer; 5. Pressing column mold; 6. Upper gasket; 7. Lower gasket; 8. Material layer; 9. Hydraulic lower ejector rod. Detailed Implementation

[0021] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] like Figure 1-2 As shown, a microwave hot pressing sintering mold includes a hydraulic upper ejector rod 1, a hydraulic lower ejector rod 9, and a hot pressing heat preservation mold. The hot pressing heat preservation mold includes a pressure head 2, a pressure column mold 5, a mold sleeve mold, an upper gasket 6, and a lower gasket 7. The top and bottom of the mold sleeve mold are respectively provided with pressure heads 2, and the upper and lower surfaces of the two pressure heads 2 are respectively connected to the hydraulic upper ejector rod 1 and the hydraulic lower ejector rod 9.

[0023] The inner layer of the mold sleeve is a mold layer 3, and the outer layer of the mold sleeve is a heat insulation layer 4. The mold layer 3 is embedded and connected to the interior of the heat insulation layer 4. An upper gasket 6 and a lower gasket 7 are provided at the bottom of the interior of the mold layer 3. A material layer is placed between the upper gasket 6 and the lower gasket 7. The bottom of the pressure column mold 5 extends into the interior of the mold layer 3 and contacts the upper gasket 6. The top of the pressure column mold 5 contacts the pressure head 2. The mold layer 3 has high density to ensure that the inner mold layer has high compressive strength. The heat insulation layer 4 has a porous structure to ensure that the heat insulation layer 4 has good heat insulation effect.

[0024] The hydraulic upper push rod 1 and the hydraulic lower push rod 9 are cylindrical, and are made of alumina or quartz material.

[0025] The pressure head 2, the pressure column mold 5, the upper gasket 6, and the lower gasket 7 are all made of boron nitride ceramic material.

[0026] The mold layer 3 is made of boron nitride material, and the insulation layer 4 is made of a combination of boron nitride and silicon oxide or aluminum silicate fiber material.

[0027] The insulation layer 4 is a porous ceramic or a high-temperature resistant aerogel.

[0028] In one embodiment, the hydraulic upper push rod 1 and hydraulic lower push rod 9 are made of alumina material; the pressure head 2, pressure column mold 5, upper gasket 6 and lower gasket 7 are all made of boron nitride ceramic material; the mold layer 3 of the inner layer of the mold sleeve mold is made of boron nitride material, and the heat insulation layer 4 of the outer layer of the mold sleeve mold is made of a combination of boron nitride and silicon oxide materials.

[0029] In another embodiment, the hydraulic upper push rod 1 and the hydraulic lower push rod 9 are made of quartz material; the pressure head 2, the pressure column mold 5, the upper gasket 6 and the lower gasket 7 are all made of boron nitride ceramic material; the mold layer 3 of the inner layer of the mold sleeve mold is made of boron nitride material, and the heat insulation layer 4 of the outer layer of the mold sleeve mold is made of aluminum silicate fiber material.

[0030] In use, firstly, assemble each component in sequence. Place the pressure head 2 on top of the hydraulic lower push rod 9, then place the insulation layer 4 on top of the pressure head 2, place the mold layer 3 into the insulation layer 4, then place the lower pad 7 at the bottom of the mold layer 3, put the material into the mold layer 3, place the upper pad 6 into the mold layer 3, and then place the pressure column mold 5 into the mold layer 3 and contact the upper pad 6. Then, the hydraulic upper push rod 1 moves downward to apply pressure to the pressure column mold 5 to press the material, and at the same time, sintering is carried out in combination with microwaves. Since the molds are all made of microwave-transparent materials, the electromagnetic field distribution in the microwave resonant cavity is not disturbed during the use of the molds, so that the microwaves can be fully applied to the sintered sample, and the material itself absorbs microwaves to generate heat.

[0031] Finally, after sintering, the hydraulic upper ejector rod 1 drives the pressure column mold 5 to move upward and away from the mold layer 3, thereby removing the pressure and taking the mold layer 3 out of the insulation layer 4. The upper gasket 6, lower gasket 7 and the product are ejected out of the mold layer 3 by the external pressure through the pressure column mold 5.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A microwave hot pressing sintering mold, comprising a hot pressing and heat preservation mold, wherein the hot pressing and heat preservation mold is installed between a hydraulic upper ejector rod (1) and a hydraulic lower ejector rod (9) during operation, characterized in that: The hot-press insulation mold includes a pressure head (2), a pressure column mold (5), a mold sleeve mold, an upper gasket (6) and a lower gasket (7). The top and bottom of the mold sleeve mold are respectively provided with pressure heads (2), and the upper and lower surfaces of the two pressure heads (2) are respectively connected to a hydraulic upper push rod (1) and a hydraulic lower push rod (9). The inner layer of the mold sleeve is a mold layer (3), and the outer layer of the mold sleeve is a heat insulation layer (4). The mold layer (3) is embedded and connected to the interior of the heat insulation layer (4). An upper gasket (6) and a lower gasket (7) are placed at the bottom of the interior of the mold layer (3). A material layer (8) is between the upper gasket (6) and the lower gasket (7). The bottom of the pressure column mold (5) extends into the interior of the mold layer (3) and contacts the upper gasket (6). The top of the pressure column mold (5) contacts the pressure head (2). The mold layer (3) has high density, and the heat insulation layer (4) has a porous structure. The mold layer (3) is made of boron nitride material, and the heat insulation layer (4) is made of a combination of boron nitride and silicon oxide or aluminum silicate fiber material; The insulation layer (4) is a porous ceramic or a high-temperature resistant aerogel.

2. The microwave hot pressing sintering mold according to claim 1, characterized in that: The hydraulic upper push rod (1) and the hydraulic lower push rod (9) are cylindrical, and both the hydraulic upper push rod (1) and the hydraulic lower push rod (9) are made of alumina or quartz material.

3. The microwave hot pressing sintering mold according to claim 1, characterized in that: The pressure head (2), the pressure column mold (5), the upper gasket (6), and the lower gasket (7) are all made of boron nitride ceramic material.

4. The method of using a microwave hot pressing sintering mold according to any one of claims 1-3, characterized in that: Step 1: Assemble the components in sequence. Place the pressure head (2) on top of the hydraulic lower push rod (9), then place the insulation layer (4) on top of the pressure head (2), place the mold layer (3) into the insulation layer (4), then place the lower pad (7) into the bottom of the mold layer (3), put the material into the mold layer (3), put the upper pad (6) into the mold layer (3), then put the pressure column mold (5) into the mold layer (3) and contact the upper pad (6). Then the hydraulic upper push rod (1) moves downward to apply pressure to the pressure column mold (5) to press the material, and at the same time combine microwave sintering. Step 2: After sintering, the hydraulic upper push rod (1) drives the pressure column mold (5) to move up and away from the mold layer (3) in sync, thereby removing the pressure and taking the mold layer (3) out of the insulation layer (4). The upper gasket (6), lower gasket (7) and product are pushed out of the mold layer (3) by the external pressure through the pressure column mold (5).

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