Non-graphite heating body hot-pressing oscillation sintering furnace for sintering oxide chuck

Abstract

The non-graphite heating body hot-pressing oscillation sintering furnace comprises a furnace shell and a double-layer cylindrical furnace body formed by welding two stainless steel flanges, the inner wall of the inner-layer flange is subjected to stainless steel polishing treatment, and the outer wall of the outer-layer flange is subjected to stainless steel matte treatment; the furnace body comprises an upper furnace body and a lower furnace body which are mutually independent; the heating chamber is positioned between the upper furnace body and the lower furnace body and consists of a stainless steel shell, a thermal insulation material and a heating body; the heating body adopts a metal heating rod; the thermal insulation material sequentially comprises a graphite cylinder and a hard carbon felt from inside to outside; and the heating bodies are distributed along the thermal insulation material in a circumferential array manner. The heating chamber of the metal heating rod and the stainless steel shell can be used for pressure sintering of the oxide ceramic chuck, and the requirement of the sintering process is met.

Description

Technical Field

[0001] The invention belongs to the technical field of sintering furnaces, and in particular relates to a non-graphite heating element hot-pressing oscillating sintering furnace for sintering oxide chucks. Background Art

[0002] In terms of ceramic chucks, both Coulomb type and JR (Johnsen-Rahbek) type ceramic chucks are basically in the research and development stage in China. The ceramic material system of the chuck is mainly oxide ceramics and aluminum nitride ceramics. At present, the sintering method of conventional oxide ceramic chucks is mainly the method of co-firing multi-layer ceramics at normal pressure and high temperature. During the sintering process, oxide ceramic chucks are prone to inconsistent radial shrinkage of various materials, resulting in deformation and cracking of the ceramic sintered body, poor bonding strength between ceramics and electrodes, uneven electrodes, uneven adsorption force and working temperature, and other common problems.

[0003] Sintering is a very important process for oxide ceramic chuck products. In this process, the product shrinks from raw porcelain to mature porcelain through high temperature. This stage will affect the flatness and absolute size of the product in terms of dimensional accuracy. In the porcelain-forming stage, due to the complex structure of the multi-layer product itself and multiple asymmetries, the stress in each direction during the shrinkage process is not the same; at the same time, the shrinkage temperature range and shrinkage rate of the metal electrode material and the oxide ceramic material are also different, and the metal electrodes inside the product are also distributed differently, resulting in different stress distributions in each area.

[0004] Therefore, the final shrinkage of each aspect of the product after sintering is different, which affects the flatness of the oxide chuck, resulting in uneven electrode, uneven adsorption force and working temperature, and even deformation and cracking of the ceramic sintered body, and poor bonding strength between the ceramic and the electrode. Summary of the invention

[0005] Purpose of the invention: To provide a non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks, so as to solve the above-mentioned problems existing in the prior art.

[0006] Technical solution: A non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks, comprising: The furnace shell includes a double-layer cylindrical furnace body welded by two stainless steel flanges, the inner wall of the inner flange is polished stainless steel, and the outer wall of the outer flange is matte stainless steel; The furnace body comprises an upper furnace body and a lower furnace body connected by bolts and independent of each other; There is a sealing groove on the flange plane, which adopts "0" ring vacuum sealing and a water cooling device (to prevent the "0" ring from aging due to excessive temperature). There is a furnace door on the furnace body, and the furnace door and the furnace body adopt a self-locking mechanism. There are vacuum system interface, infrared temperature measurement interface, thermocouple temperature measurement interface, 3 electrode interfaces with water cooling devices, visual interface, spare interface, and the charging and discharging ports are set on the upper furnace cover.

[0007] The heating chamber is located between the upper furnace body and the lower furnace body and is composed of a stainless steel shell, a heat-insulating material and a heating body; The heating body adopts a metal heating rod; The insulation materials are graphite tube and hard carbon felt from inside to outside. The heating bodies are distributed in a circular arrangement along the heat-insulating material.

[0008] Two temperature measuring points are set at radial positions around the working area of ​​the heating chamber, and the temperature of the equipment is measured and controlled by a temperature measurement method combining an infrared thermometer and a double platinum-rhodium thermocouple.

[0009] At 1400℃, a platinum-rhodium thermocouple with strong oxidation resistance, high mechanical strength and good chemical stability is used to measure the temperature in the furnace. When the temperature is above 1400℃, the double platinum-rhodium thermocouple is retracted to the outside through the dragging mechanism, and the imported infrared thermometer starts to work to accurately measure the temperature in the furnace. The heating, insulation and cooling processes are realized by the programmable temperature controller. The actual temperature and set temperature in the furnace are displayed synchronously and in real time on the instrument cabinet. The heating rate is 0~25℃ / min, and the temperature control accuracy is ±1℃.

[0010] The dragging mechanism is a prior art and can be selected in the art.

[0011] The heating chamber of traditional pressure sintering equipment uses a graphite heating element and a graphite protective layer, but the atmosphere provided by this material cannot meet the sintering process requirements of the oxide ceramic chuck, so the ceramic sintered body deforms and cracks. The present invention provides a heating chamber with a metal heating rod and a stainless steel shell, which can be used for pressure sintering of oxide ceramic chucks to meet the sintering process requirements.

[0012] In a further embodiment, an upper furnace cover is provided at the end of the upper furnace body, and a lower furnace cover is provided at the bottom of the lower furnace body.

[0013] In a further embodiment, it further comprises a furnace frame for placing the furnace body, and a lifting mechanism arranged at the end of the furnace frame.

[0014] In a further embodiment, the furnace frame includes a column, an upper beam disposed at an end of the column, a lower beam disposed at a bottom of the column, and a middle cross beam disposed on the column and between the upper beam and the lower beam; A middle beam support is provided between the middle cross beam and the lower beam; A furnace body fixing plate is arranged on the column, and the furnace body fixing plate abuts against the lower furnace cover.

[0015] In a further embodiment, the furnace body is located between the middle beam and the upper beam.

[0016] In a further embodiment, the lifting mechanism includes a lead screw, an upper fixed plate sleeved with the lead screw, a fixed rod connected to the upper fixed plate and connected to the upper beam, an upper hanging beam sleeved with the lead screw and the fixed rod, and a furnace body pull rod connected to the upper hanging beam; The furnace body pull rod is connected to the upper furnace body.

[0017] In a further embodiment, an anti-rotation rod is provided on the middle cross beam, a cross frame is provided on the anti-rotation rod, a lower metal pressure head and a support body are provided on the cross frame, and a furnace body fixing plate is also provided on the column; A pressure sensor is provided below the lower metal pressure head; A displacement sensor is arranged on the supporting body.

[0018] In a further embodiment, an upper metal pressure head and a displacement measurement and control device are provided on the upper beam.

[0019] Beneficial effects: The present invention discloses a hot-pressing oscillating sintering furnace for sintering oxide chucks with a non-graphite heating element. The heating chamber of the conventional press sintering equipment adopts a graphite heating element and a graphite protective layer, but the atmosphere provided by this material cannot meet the sintering process requirements of the oxide ceramic chuck, so deformation and cracking of the ceramic sintered body occur. The present invention provides a heating chamber with a metal heating rod and a stainless steel shell, which can be used for the pressurized sintering of the oxide ceramic chuck to meet the sintering process requirements. At the same time, the upper furnace body and the lower furnace body are designed to be split, and the upper furnace body and the lower furnace body can be bolted together as needed to complete the overall movement, or the bolts can be loosened to allow the upper furnace body and the lower furnace body to move separately. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the device of the present invention.

[0021] The accompanying drawings are marked as follows: 1. fixing rod; 2. screw; 3. upper hanging beam; 4. furnace body pull rod; 5. upper fixing plate; 6. upper metal pressure head; 7. upper furnace cover; 8. upper furnace body; 9. lower furnace body; 10. column; 11. lower furnace cover; 12. support body; 13. lower metal pressure head; 14. middle cross beam; 15. furnace body fixing plate; 16. anti-rotation rod; 17. middle beam support; 18. lower beam. DETAILED DESCRIPTION

[0022] The present application relates to a non-graphite heating element hot pressing oscillating sintering furnace for sintering oxide ceramic chucks. The heating chamber of conventional pressing sintering equipment generally uses a graphite heating element and a graphite protective layer. However, the atmosphere released by the graphite material during the sintering process contains a certain amount of carbon, which is a disadvantageous factor for the sintering process of oxide ceramic chucks.

[0023] Specifically, the presence of carbon easily reacts with oxide ceramics, causing stress inside the sintered body, which in turn causes deformation and cracking of the ceramic sintered body, and also causes the risk of carbonization of the metal heating electrode inside the sintered body. In addition, the atmosphere created by the graphite material may also lead to insufficient bonding strength at the interface between the metal and the ceramic, affecting the performance of the final product.

[0024] In order to overcome the above-mentioned defects, the present invention provides an innovative heating chamber design, which adopts a combination of a metal heating rod and a stainless steel shell.

[0025] The metal heating rod has stable heating performance and good thermal conductivity, which can ensure uniform temperature distribution during the sintering process.

[0026] At the same time, the stainless steel shell not only has excellent corrosion resistance, but also can effectively isolate the interference of external impurities on the sintering process.

[0027] More importantly, the combination of the metal heating rod and the stainless steel shell will not produce an atmosphere that is harmful to oxide ceramics, thereby avoiding the deformation and cracking problems of the sintered body, and significantly improving the bonding strength of the metal-ceramic interface, eliminating the risk of carbonization.

[0028] In general, the combination of metal heating rod and stainless steel shell not only avoids the harmful effects of graphite material on oxide ceramics, but also improves the stability and reliability of the sintering process.

[0029] In the design of the heating chamber, the present invention also designs the upper furnace body and the lower furnace body as a split structure. This design allows the user to connect the upper furnace body and the lower furnace body by bolts according to actual needs to achieve overall movement.

[0030] At the same time, after loosening the bolts, the upper furnace body and the lower furnace body can also move independently, thus improving the flexibility and applicability of the equipment and meeting the diverse sintering needs of users.

[0031] In addition, as an important part of the oscillating sintering furnace, the present invention is also equipped with a dedicated hydraulic servo device. The device can generate precise oscillating pressure, realize the oscillating pressure control during the sintering process, promote the diffusion and densification of materials during the sintering process, and further improve the quality and performance of the sintered body.

[0032] In summary, the present invention can be widely used in the sintering process of preparing high-performance materials, especially the pressure sintering of oxide ceramic chucks, and has significant technical advantages and economic benefits.

[0033] The following is a detailed explanation through specific implementation methods.

[0034] A non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks, comprising: The furnace shell includes a double-layer cylindrical furnace body welded by two stainless steel flanges, the inner wall of the inner flange is polished stainless steel, and the outer wall of the outer flange is matte stainless steel; The furnace body comprises an upper furnace body 8 and a lower furnace body 9 which are connected by bolts and are independent of each other; A sealing groove is opened on the flange plane, and a "0" ring vacuum seal is adopted, and a water cooling device is provided (to prevent the "0" ring from aging due to excessive temperature). A furnace door is provided on the furnace body, and the furnace door and the furnace body adopt a self-locking mechanism. The furnace body is provided with a vacuum system interface, an infrared temperature measurement interface, a thermocouple temperature measurement interface, 3 electrode interfaces with water cooling devices, a visual interface, a spare interface, and the charging and discharging ports are arranged on the upper furnace cover 7.

[0035] The heating chamber is located between the upper furnace body 8 and the lower furnace body 9 and is composed of a stainless steel shell, a heat-insulating material and a heating body; The heating body adopts a metal heating rod; The insulation materials are graphite tube and hard carbon felt from inside to outside. The heating bodies are distributed in a circular arrangement along the heat-insulating material.

[0036] Two temperature measuring points are set at radial positions around the working area of ​​the heating chamber, and the temperature of the equipment is measured and controlled by a temperature measurement method combining an infrared thermometer and a double platinum-rhodium thermocouple.

[0037] At 1400℃, a platinum-rhodium thermocouple with strong oxidation resistance, high mechanical strength and good chemical stability is used to measure the temperature in the furnace. When the temperature is above 1400℃, the double platinum-rhodium thermocouple is retracted to the outside through the dragging mechanism, and the imported infrared thermometer starts to work to accurately measure the temperature in the furnace. The heating, insulation and cooling processes are realized by the programmable temperature controller. The actual temperature and set temperature in the furnace are displayed synchronously and in real time on the instrument cabinet. The heating rate is 0~25℃ / min, and the temperature control accuracy is ±1℃.

[0038] The dragging mechanism is a prior art and can be selected in the art.

[0039] The heating chamber of traditional pressure sintering equipment uses a graphite heating element and a graphite protective layer, but the atmosphere provided by this material cannot meet the sintering process requirements of the oxide ceramic chuck, so the ceramic sintered body deforms and cracks. The present invention provides a heating chamber with a metal heating rod and a stainless steel shell, which can be used for pressure sintering of oxide ceramic chucks to meet the sintering process requirements.

[0040] An upper furnace cover 7 (sealed and fixedly connected) is disposed at the end of the upper furnace body 8 , and a lower furnace cover 11 is disposed at the bottom of the lower furnace body 9 .

[0041] It also includes a furnace frame for placing the furnace body, and a lifting mechanism arranged at the end of the furnace frame.

[0042] The furnace frame includes a column 10, an upper beam arranged at the end of the column 10, a lower beam 18 arranged at the bottom of the column 10, and a middle cross beam 14 arranged on the column 10 and located between the upper beam and the lower beam 18; The middle cross beam 14 is connected to an external hydraulic system, and the hydraulic system drives the middle cross beam 14 to move up and down on the column 10; A middle beam support 17 is provided between the middle beam 14 and the lower beam 18. A linear motion mechanism is provided at the bottom of the middle beam support 17. The linear motion mechanism drives the middle beam support 17 to move to both sides, thereby giving up the contact with the middle beam 14, so that the middle beam 14 can be lowered. The center beam support 17 may also be directly designed on both sides of the center cross beam 14, and the center beam support 17 is driven by a linear motion mechanism to clamp the center cross beam 14 to complete the support.

[0043] The column 10 is provided with a furnace body fixing plate, and the furnace body fixing plate abuts against the lower furnace cover 11 .

[0044] The furnace body is located between the middle beam and the upper beam.

[0045] The lifting mechanism includes a screw 2, an upper fixing plate 5 sleeved on the screw 2, a fixing rod 1 connected to the upper fixing plate 5 and connected to the upper beam, an upper hanging beam 3 sleeved on the screw 2 and the fixing rod 1, and a furnace body pull rod 4 connected to the upper hanging beam 3; The furnace body pull rod 4 is connected to the upper furnace body 8 .

[0046] The lead screw 2 is externally connected to a driving source, and the driving source includes a motor.

[0047] The middle cross beam 14 is provided with an anti-rotation rod 16, the anti-rotation rod 16 is provided with a cross frame, the cross frame is provided with a lower metal pressure head 13 and a support body 12, and the column 10 is also provided with a furnace body fixing plate 15; A pressure sensor is provided below the lower metal pressure head 13; The support body 12 is provided with a displacement sensor.

[0048] A set of displacement measurement and control devices are installed at the upper and lower metal pressure heads 13 respectively. A grating displacement collector is used to collect displacement information, and a visual displacement recording window is used to display data. The axial displacement collection point is located on the metal pressure head, which is convenient for accurate displacement measurement. It can realize real-time monitoring of the compression and sintering densification process and control the relative density of the sintered product.

[0049] Bidirectional displacement is displayed in real time, and the displacement measurement accuracy reaches 0.01mm. Load sensor and secondary instrument are used to display the press pressure.

[0050] Working principle description: The furnace body is heated by a metal heating rod to complete the sintering of the oxide chuck. During the sintering process, the upper metal pressure head 6 and the lower metal pressure head 13 are used to adjust the constant pressure and oscillating pressure of the furnace body. When adjusting the pressure; During the overall movement, the upper furnace body 8 and the lower furnace body 9 are connected by bolts, and the lead screw 2 is driven to rotate by the motor, so that the upper hanging beam 3 is lifted and lowered along the fixed rod 1, thereby driving the furnace body to lift and lower. When the lower furnace cover 11 is opened, the middle beam 14 is raised by 10 mm through the hydraulic system, so that in the subsequent steps, the middle beam support 17 will not be hindered by the middle beam 14 when it gives up the contact with the middle beam 14. At the same time, it also helps the middle beam 14 to smoothly drive the lower furnace cover 11 to open when it descends.

[0051] After the middle cross beam 14 rises to the predetermined position, the middle beam support 17 abandons the contact with the middle cross beam 14. These middle beam support 17 play the role of supporting and fixing the lower furnace cover 11 and the lower furnace body 9 in the initial state, and abandon the support for the lower furnace cover 11 and the lower furnace body 9 in the working state. When the upper furnace body 8 is connected with the lower furnace body 9 by bolts, the lower furnace cover 11 is opened. When the upper furnace body 8 is not connected with the lower furnace body 9 by bolts, the upper furnace body 8 and the lower furnace body 9 are separated. This design not only simplifies the opening operation of the furnace cover, but also improves the stability and safety of the operation. When the lower furnace cover 11 is fully opened, the operator can easily load and unload the sintered products. This design greatly improves work efficiency and operation safety; The lower furnace body 9 is designed to be able to be raised and lowered separately, which allows the lower furnace body 9 to be raised and lowered independently of the upper furnace body 8. This separate design not only improves the flexibility of operation, but also makes the opening and closing of the lower furnace door faster and more convenient, which is convenient for equipment maintenance.

[0052] When the insulation layer and heating elements need to be disassembled or maintained, loosen the bolts of the upper road body and the lower furnace body 9, and drive the lead screw 2 to rotate through the motor, so that the upper hanging beam 3 can be lifted and lowered along the fixed rod 1, thereby driving the furnace body pull rod 4 to drive the upper furnace body 8 to be lifted and lowered separately, so as to facilitate the disassembly and assembly of the internal insulation layer and heating elements. When the overall lifting is required, it is completed by bolt connection.

[0053] The preferred specific embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above specific embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks, characterized in that: include: The furnace shell includes a double-layer cylindrical furnace body welded by two stainless steel flanges, the inner wall of the inner flange is polished stainless steel, and the outer wall of the outer flange is matte stainless steel; The furnace body comprises an upper furnace body (8) and a lower furnace body (9) which are connected by bolts and are independent of each other; A heating chamber, located between the upper furnace body (8) and the lower furnace body (9), and composed of a stainless steel shell, a heat-insulating material and a heating body; The heating body adopts a metal heating rod; The insulation materials are graphite tube and hard carbon felt from inside to outside. The heating bodies are distributed in a circular arrangement along the heat-insulating material.

2. A non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 1, characterized in that: An upper furnace cover (7) is provided at the end of the upper furnace body (8), and a lower furnace cover (11) is provided at the bottom of the lower furnace body (9).

3. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 1, characterized in that: It also includes a furnace frame for placing the furnace body, and a lifting mechanism arranged at the end of the furnace frame.

4. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 3, characterized in that: The furnace frame comprises a column (10), an upper beam arranged at the end of the column (10), a lower beam (18) arranged at the bottom of the column (10), and a middle cross beam (14) arranged on the column (10) and located between the upper beam and the lower beam (18); A middle beam support (17) is provided between the middle cross beam (14) and the lower beam (18); A furnace body fixing plate is provided on the upright column (10), and the furnace body fixing plate abuts against the lower furnace cover (11).

5. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 3, characterized in that: The furnace body is located between the middle beam and the upper beam.

6. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 3, characterized in that: The lifting mechanism comprises a lead screw (2), an upper fixing plate (5) sleeved on the lead screw (2), a fixing rod (1) connected to the upper fixing plate (5) and connected to an upper beam, an upper hanging beam (3) sleeved on the lead screw (2) and the fixing rod (1), and a furnace body pull rod (4) connected to the upper hanging beam (3); The furnace body pull rod (4) is connected to the upper furnace cover (7).

7. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 4, characterized in that: An anti-rotation rod (16) is provided on the middle cross beam (14), an upper cross frame is provided on the anti-rotation rod (16), a lower metal pressure head (13) and a support body (12) are provided on the cross frame, and a furnace body fixing plate (15) is also provided on the column (10).

8. The non-graphite heating element hot pressing oscillation sintering furnace for sintering oxide chucks according to claim 4, characterized in that: An upper metal pressure head (6) and a displacement measurement and control device are provided on the upper beam.

Images