Ultrasonic vibration assisted microwave sintering device and sintering method

Abstract

The invention relates to the technical field of ultrasonic microwave-assisted sintering, in particular to an ultrasonic vibration-assisted microwave sintering device and a sintering method. The ultrasonic-vibration-assisted microwave sintering device comprises a rack, a microwave oven cavity, a mold, an ultrasonic vibration mechanism and a one-way pressure mechanism, the microwave oven cavity is fixed to the upper end of the rack through a fixing support, the mold is arranged in the microwave oven cavity, the ultrasonic vibration mechanism is arranged above the microwave oven cavity, and the one-way pressure mechanism is arranged in the microwave oven cavity. The ultrasonic vibration mechanism is provided with a tool head, the upper end of the microwave oven cavity is provided with a channel allowing the tool head to enter, and the driving end of the one-way pressure mechanism is in transmission connection with the ultrasonic vibration mechanism and used for driving the ultrasonic vibration mechanism to move up and down. And the tool head extends into the microwave oven cavity to be close to or far away from the mold. According to the sintering device, the production efficiency can be remarkably improved, and products uniform in structure and stable in performance can be sintered easily.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic microwave assisted sintering, and in particular to an ultrasonic vibration assisted microwave sintering device. Background Art

[0002] At present, the commonly used sintering technology in hot pressing sintering technology is atmospheric pressure sintering, that is, heating the powder or compact to a certain temperature in the atmosphere to make the particles bond and transfer materials, and finally form a dense sintered body. However, this method has some obvious shortcomings. Many ceramic and metal materials need to be fully sintered at extremely high temperatures, which not only puts high demands on heating equipment and increases energy consumption, but also may cause grain growth and phase change at high temperatures, thereby affecting the performance of the material. In addition, for some difficult-to-sinter materials, such as high-melting-point ceramics and nanomaterials, atmospheric pressure sintering is often difficult to obtain the ideal density.

[0003] The utility model patent with publication number CN211386900U proposes a microwave sintering device with the characteristics of fast heating speed, high energy utilization rate, high heating efficiency, etc. However, the device cannot achieve uniform heating of the material, and the low dielectric loss material has low microwave absorption efficiency, and the heating effect is not ideal.

[0004] In view of this phenomenon, the present invention aims to provide an ultrasonic vibration assisted microwave sintering device and a sintering method which combine ultrasonic technology with microwave sintering technology. Summary of the invention

[0005] The object of the present invention is to provide an ultrasonic vibration assisted microwave sintering device and a sintering method.

[0006] To achieve the above-mentioned purpose, the present invention provides an ultrasonic vibration-assisted microwave sintering device, comprising a frame, a microwave oven cavity, a mold, an ultrasonic vibration mechanism and a one-way pressure mechanism, wherein the microwave oven cavity is fixed to the upper end of the frame by a fixing bracket, the mold is arranged in the microwave oven cavity, the ultrasonic vibration mechanism is arranged above the microwave oven cavity, the ultrasonic vibration mechanism is provided with a tool head, and the upper end of the microwave oven cavity is provided with a channel for the tool head to enter the interior thereof, the driving end of the one-way pressure mechanism is transmission-connected with the ultrasonic vibration mechanism, and is used to drive the ultrasonic vibration mechanism to move up and down until the tool head extends into the microwave oven cavity and approaches or moves away from the mold.

[0007] Further, the fixed bracket includes a moving plate and a plurality of guide posts. The moving plate is slidably mounted on the plurality of guide posts. The microwave oven cavity is disposed below the moving plate. The ultrasonic vibration mechanism is fixed on the moving plate. The one-way pressure mechanism is fixed on the fixed bracket, and its driving end is fixedly connected to the moving plate. The one-way pressure mechanism drives the moving plate to drive the ultrasonic vibration mechanism to move up and down.

[0008] Further, a heat insulation pressure head is provided in the microwave oven cavity. The mold is fixed to the upper end of the heat insulation pressure head. A metal top post is provided at the bottom of the microwave oven cavity.

[0009] Further, the ultrasonic vibration mechanism includes a ultrasonic transducer, a ultrasonic energy concentrator and the tool head which are connected in sequence. The ultrasonic vibration mechanism is fixed on the moving plate. A bellows communicating with the inside thereof is provided at the upper end of the microwave oven cavity. One end of the bellows away from the microwave oven cavity is fixedly connected to the moving plate. The tool head is located inside the bellows.

[0010] Further, the one-way pressure mechanism includes a servo electric cylinder. A pressure head protection cover is provided at the driving end of the servo electric cylinder. The pressure head protection cover covers the outside of the ultrasonic transducer and is fixedly connected to the upper end of the moving plate. The servo electric cylinder drives the pressure head protection cover to drive the moving plate and the ultrasonic transducer to move along the axial direction of the plurality of guide posts.

[0011] Further, a pressure detection unit is provided at the upper end of the pressure head protection cover.

[0012] Further, the pressure detection unit is a pressure sensor.

[0013] Further, there are four guide posts.

[0014] A sintering method for ultrasonic vibration-assisted microwave sintering, which uses the above sintering device for sintering, includes the following steps:

[0015] S1. Confirm that the working states of all components of the sintering device are normal. Open the furnace door of the microwave oven cavity, put in the mold containing the material to be sintered, and close the furnace door;

[0016] S2. According to the sintering process requirements of the material to be sintered, evacuate the inside of the microwave oven cavity and introduce a protective gas;

[0017] S3. Control the one-way pressure mechanism to slowly press down the tool head until it contacts the powder to be sintered in the mold; start the ultrasonic vibration mechanism when the tool head contacts the powder to be sintered, and press down the tool head until the required pressure for the material to be sintered is reached;

[0018] S4. After the tool head applies the target pressure to the material to be sintered, start microwave sintering by controlling the microwave cavity to heat up the material to be sintered;

[0019] S5. After sintering is completed, turn off the ultrasonic vibration mechanism and the microwave cavity, control the unidirectional pressure mechanism to slowly relieve the pressure, and then cool down the microwave cavity 0 by using the cooling water circulation system;

[0020] S6. After the pressure is completely removed and the temperature in the furnace drops to room temperature, open the furnace door, take out the sintering mold, clean the inside of the microwave cavity, and turn off each component to complete sintering.

[0021] The beneficial effects of the present invention are: (1) The ultrasonic vibration-assisted microwave sintering device of the present invention can significantly improve production efficiency compared with traditional sintering devices. The distribution of the microwave field inside the material is relatively uniform, enabling the material to be heated almost synchronously as a whole, reducing the internal thermal stress caused by the temperature gradient, and facilitating the sintering of products with uniform structure and stable performance. In addition, the ultrasonic vibration-assisted microwave sintering device of the present invention also has the advantages of low implementation cost, simple structure, and convenient operation;

[0022] (2) The sintering method of the present invention combines ultrasonic vibration and microwave sintering technologies. During sintering, the microwave in the microwave cavity can directly act on the polar molecules inside the material, causing them to vibrate rapidly and generate heat, achieving rapid heating of the whole material and greatly shortening the sintering time required. Compared with traditional sintering methods, it can significantly improve production efficiency. The distribution of the microwave field inside the material is relatively uniform, enabling the material to be heated almost synchronously as a whole, reducing the internal thermal stress caused by the temperature gradient, and facilitating the sintering of products with uniform structure and stable performance. The ultrasonic vibration mechanism provides ultrasonic vibration, and the ultrasonic vibration generated by the ultrasonic wave promotes the mutual filling of pores between particles, improving the densification degree of the material. The energy generated by the ultrasonic vibration also inhibits the growth of grains, making the microstructure of the material more uniform. The densification degree of the material is increased, the grains are refined and evenly distributed, resulting in a significant improvement in the hardness and strength of the material. Compared with traditional sintering devices, it can significantly improve production efficiency. The distribution of the microwave field inside the material is relatively uniform, enabling the material to be heated almost synchronously as a whole, reducing the internal thermal stress caused by the temperature gradient, and facilitating the sintering of products with uniform structure and stable performance. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art.

[0024] Figure 1 It is a schematic structural diagram of an ultrasonic vibration-assisted microwave sintering device of the present invention;

[0025] Figure 2 is a schematic structural view of the microwave oven cavity of the present invention;

[0026] Figure 3 is a schematic structural view of the ultrasonic vibration mechanism of the present invention. Specific Embodiments

[0027] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0028] In the description of the present invention, it should be understood that the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0029] Please refer to Figures 1-3 , the present invention provides an ultrasonic vibration-assisted microwave sintering device, including a frame 10, a microwave oven cavity 80, a mold 30, an ultrasonic vibration mechanism and a unidirectional pressure mechanism. The microwave oven cavity 80 is fixed to the upper end of the frame 10 through a fixing bracket 40. The mold 30 is disposed in the microwave oven cavity 80. The ultrasonic vibration mechanism is disposed above the microwave oven cavity 80. The ultrasonic vibration mechanism is provided with a tool head 20. The upper end of the microwave oven cavity 80 is provided with a channel for the tool head 20 to enter its interior. The driving end of the unidirectional pressure mechanism is in transmission connection with the ultrasonic vibration mechanism, and is used to drive the ultrasonic vibration mechanism to move up and down until the tool head 20 extends into the microwave oven cavity 80 to be close to or away from the mold 30.

[0030] In the present invention, the ultrasonic vibration mechanism and the one-way pressure mechanism are both fixed on the fixed bracket 40, and the mold 30 is used to place the sintering material. The microwave in the microwave oven cavity 80 can directly act on the polar molecules inside the material during sintering, causing it to vibrate rapidly and generate heat, thereby realizing rapid heating of the entire material, greatly shortening the time required for sintering. Compared with the traditional sintering method, it can significantly improve production efficiency. The distribution of the microwave field inside the material is relatively uniform, which can make the entire material almost heated synchronously, reducing the internal thermal stress caused by the temperature gradient, and is conducive to sintering products with uniform structure and stable performance. The ultrasonic vibration mechanism provides ultrasonic vibration, and uses the ultrasonic vibration generated by ultrasonic waves to promote the mutual filling of pores between particles, thereby improving the densification degree of the material. The energy generated by the ultrasonic vibration can also inhibit the growth of grains, making the microstructure of the material more uniform, the densification degree of the material is improved, the grains are refined and evenly distributed, and the hardness and strength of the material are significantly improved. The ultrasonic vibration mechanism transmits the ultrasonic vibration to the sintering material on the mold 30 through the tool head 20 to complete the ultrasonic vibration assisted sintering.

[0031] As an embodiment of the present invention, an insulating pressure head 81 is provided in the microwave oven cavity 80, the mold 30 is fixed at the upper end of the insulating pressure head 81, a metal top column 50 is provided at the bottom of the microwave oven cavity 80, and a bellows 60 connected to the interior thereof is provided at the upper end, and the end of the bellows 60 away from the microwave oven cavity 80 is connected and fixed to a fixed bracket 40.

[0032] In the present invention, the metal top column 50 is fixedly mounted on the fixing bracket 40 to fix the microwave cavity 80. The heat-insulating pressing head 81 is used to fix the mold 30 and to keep the temperature in the microwave cavity 80 stable during the pressing process. The bellows 60 is used to prevent the microwave energy in the microwave cavity 80 from leaking.

[0033] As an embodiment of the present invention, the ultrasonic vibration mechanism includes an ultrasonic transducer 21, an ultrasonic concentrator 22 and the tool head 20 connected in sequence, and the tool head 20 is located in the bellows 60; the ultrasonic transducer 21 is transmission-connected to the driving end of the unidirectional pressure mechanism.

[0034] In the present invention, the ultrasonic transducer 21 provides ultrasonic vibration. The ultrasonic transducer 21 converts the received ultrasonic electrical signal into a mechanical vibration signal according to the piezoelectric effect or magnetostrictive effect and outputs it to the ultrasonic energy concentrator 22. The ultrasonic energy concentrator 22 amplifies the amplitude of the received mechanical vibration signal and realizes energy concentration. The mechanical vibration signal enhanced by the ultrasonic energy concentrator 22 acts on the material to be sintered through the tool head 20. Preferably, the ultrasonic transducer 21, the ultrasonic energy concentrator 22, the tool head 20, the mold 30, the heat insulation pressure head 81, and the metal top column 50 are coaxially arranged, which can make the mold 30 receive uniform force and improve the stability of the overall device.

[0035] As another embodiment of the present invention, the fixed bracket 40 includes a moving plate 41 and a plurality of guide columns 42. The moving plate 41 is slidably mounted on the plurality of guide columns 42. The ultrasonic transducer 21 is fixedly mounted on the moving plate 41. The unidirectional pressure mechanism is arranged at the upper end of the fixed bracket 40 and includes a servo electric cylinder 70. A pressure head protection cover 71 is provided at the driving end of the servo electric cylinder 70. The pressure head protection cover 71 covers the outside of the ultrasonic transducer 21 and is fixedly connected to the upper end of the moving plate 41. The servo electric cylinder 70 drives the pressure head protection cover 71 to drive the moving plate 41 and the ultrasonic transducer 21 to move along the axial direction of the plurality of guide columns 42.

[0036] In the present invention, when the servo electric cylinder 70 drives the pressure head protection cover 71 to drive the moving plate 41 and the ultrasonic transducer 21 to move along the axial direction of the plurality of guide columns 42, the tool head 20 can be made to approach or move away from the mold 30. Preferably, there are four guide columns 42, and the ultrasonic energy concentrator 22 is fixedly connected to the moving plate 41 through a flange. The unidirectional pressure mechanism of the present invention has the advantages of straight driving trajectory, high driving efficiency, simple structure, and low implementation cost.

[0037] As another embodiment of the present invention, a pressure detection unit is provided at the upper end of the pressure head protection cover 71, and the pressure detection unit is a pressure sensor 72.

[0038] In the present invention, the pressure sensor 72 is used to detect the pressure exerted by the unidirectional pressure mechanism on the ultrasonic vibration mechanism, ensuring the sintering effect of the ultrasonic vibration-assisted microwave sintering process.

[0039] The sintering method of the ultrasonic vibration-assisted microwave sintering device of the present invention includes the following steps:

[0040] (1) Confirm that the working states of all components of the sintering device are normal. Open the furnace door of the microwave oven cavity 80, place the mold 30 containing the material to be sintered on the heat insulation pressure head 81, and close the furnace door.

[0041] (2) According to the sintering process requirements of the material to be sintered, evacuate the inside of the microwave oven cavity 80 and introduce a protective gas; specifically, as another embodiment, the ultrasonic vibration-assisted microwave sintering can also be directly carried out under air conditions;

[0042] (3) Control the one-way pressure mechanism to slowly lower the tool head 20 until it contacts the powder to be sintered in the mold 30; when the tool head 20 contacts the powder to be sintered, start the ultrasonic vibration mechanism and lower the tool head 20 until the pressure required for the material to be sintered is reached;

[0043] (4) Control the microwave oven cavity 80 to start microwave sintering after the tool head 20 applies the target pressure to the material to be sintered, so as to raise the temperature of the material to be sintered;

[0044] (5) After sintering is completed, turn off the ultrasonic vibration mechanism and the microwave oven cavity 80, control the one-way pressure mechanism to slowly relieve the pressure, and then cool down the microwave oven cavity 80 by using the cooling water circulation system;

[0045] (6) After the pressure is completely relieved and the temperature in the furnace drops to room temperature, open the furnace door, take out the sintering mold 30, clean the inside of the microwave oven cavity 80, and turn off each component, and the sintering is completed.

[0046] The above-disclosed are only one or more preferred embodiments of the present application, and the scope of rights of the present application cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. An ultrasonic vibration assisted microwave sintering device, characterized in that: The invention comprises a frame, a microwave oven cavity, a mold, an ultrasonic vibration mechanism and a one-way pressure mechanism, wherein the microwave oven cavity is fixed to the upper end of the frame by a fixing bracket, the mold is arranged in the microwave oven cavity, the ultrasonic vibration mechanism is arranged above the microwave oven cavity, the ultrasonic vibration mechanism is provided with a tool head, and the upper end of the microwave oven cavity is provided with a channel for the tool head to enter the interior thereof, and the driving end of the one-way pressure mechanism is transmission-connected with the ultrasonic vibration mechanism, and is used for driving the ultrasonic vibration mechanism to move up and down until the tool head extends into the microwave oven cavity and approaches or moves away from the mold.

2. The ultrasonic vibration assisted microwave sintering device according to claim 1, characterized in that: The fixed bracket includes a movable plate and a plurality of guide pillars, the movable plate is slidably mounted on the plurality of guide pillars, the microwave oven cavity is arranged below the movable plate, the ultrasonic vibration mechanism is fixed on the movable plate, the one-way pressure mechanism is fixed on the fixed bracket, and a driving end thereof is connected and fixed to the movable plate, and the one-way pressure mechanism drives the movable plate to drive the ultrasonic vibration mechanism to move up and down.

3. The ultrasonic vibration assisted microwave sintering device according to claim 1, characterized in that: A heat-insulating pressure head is arranged in the cavity of the microwave oven, the mold is fixed on the upper end of the heat-insulating pressure head, and a metal top column is arranged at the bottom of the cavity of the microwave oven.

4. The ultrasonic vibration assisted microwave sintering device according to claim 2, characterized in that: The ultrasonic vibration mechanism includes an ultrasonic transducer, an ultrasonic concentrator and the tool head which are connected in sequence. The ultrasonic concentrator is fixed on the movable plate. The upper end of the microwave oven cavity is provided with a bellows which is connected to its interior. The end of the bellows away from the microwave oven cavity is connected and fixed to the movable plate. The tool head is located in the bellows.

5. The ultrasonic vibration assisted microwave sintering device according to claim 4, characterized in that: The one-way pressure mechanism includes a servo electric cylinder, a driving end of the servo electric cylinder is provided with a pressure head protection cover, the pressure head protection cover is arranged outside the ultrasonic transducer and is connected and fixed to the upper end of the movable plate, and the servo electric cylinder drives the pressure head protection cover to drive the movable plate and the ultrasonic transducer to move axially along the multiple guide columns.

6. The ultrasonic vibration assisted microwave sintering device according to claim 5, characterized in that: A pressure detection unit is provided at the upper end of the pressure head protection cover.

7. The ultrasonic vibration assisted microwave sintering device according to claim 6, characterized in that: The pressure detection unit is a pressure sensor.

8. The ultrasonic vibration assisted microwave sintering device according to claim 2, characterized in that: There are four guide columns.

9. A sintering method using ultrasonic vibration assisted microwave sintering, characterized in that: The sintering device according to any one of claims 1 to 8 is used for sintering, comprising the following steps: S1. Confirm that all parts of the sintering device are in normal working condition, open the oven door of the microwave oven cavity, put in the mold containing the material to be sintered, and close the oven door; S2. According to the sintering process requirements of the material to be sintered, the interior of the microwave oven cavity is evacuated and a protective gas is introduced; S3, by controlling the one-way pressure mechanism, the tool head is slowly pressed down until it contacts the powder to be sintered in the mold; when the tool head contacts the powder to be sintered, the ultrasonic vibration mechanism is started, and the tool head starts to press down until the pressure required by the material to be sintered is reached; S4, starting microwave sintering after the tool head applies a target pressure to the material to be sintered by controlling the microwave oven cavity, so that the material to be sintered is heated; S5, after sintering is completed, the ultrasonic vibration mechanism and the microwave oven cavity are turned off, the one-way pressure mechanism is controlled to slowly release the pressure, and then the microwave oven cavity is cooled by using a cooling water circulation system; S6. After the pressure is completely released and the temperature in the furnace drops to room temperature, open the furnace door, take out the sintering mold, clean the inside of the microwave oven cavity, close all components, and sintering is completed.

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