Heater for ultrahigh-temperature vacuum sintering

Abstract

The invention relates to the technical field of graphite heaters, and discloses an ultrahigh-temperature vacuum sintering heater which comprises a graphite heater body, a sample groove is formed in the middle of the graphite heater body, a graphite cover plate used for covering the sample groove is arranged on the graphite heater body, and sawtooth grooves are formed in the groove wall of the graphite cover plate and the groove wall of the sample groove in a penetrating mode. Graphite electrodes are symmetrically and electrically connected to the graphite heater, water-cooled electrodes are detachably installed at the ends, away from the graphite heater, of the graphite electrodes, connecting blocks are locked and fixed to the water-cooled electrodes, and power is supplied to the connecting blocks through an external power source of a cable. According to the graphite heater disclosed by the invention, the current value passing through each surface of the sample groove of the graphite heater is equal to the current value passing through the graphite cover plate, so that a test sample obtains a more stable and more uniform heating effect.

Description

Technical Field

[0001] The invention relates to the technical field of graphite heaters, in particular to a heater for ultra-high temperature vacuum sintering. Background Art

[0002] Joule heating utilizes the Joule effect inherent in conductive materials, applying an electrical environment to them, causing them to reach extremely high temperatures in a very short period of time. By rapidly heating a material, changes in its physical properties under extreme environments and severe thermal shock can be examined.

[0003] Nowadays, the scientific research industry pays more attention to the changes in the physical properties of materials at higher temperatures, such as alloys, carbon, ceramics, etc. When heat treatment of materials is required, most of them are carried out in reactors or reactors. With the development of science and technology, scientific researchers are constantly exploring the heat treatment process of materials, and have higher requirements for the uniformity of heating of test samples during heating. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a heater for ultra-high temperature vacuum sintering, which solves the problem in the existing technology of improving the heating uniformity and stability of test samples during material thermal testing due to the limitations of process and equipment.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a heater for ultra-high temperature vacuum sintering, comprising a graphite heater, a sample slot is opened in the middle of the graphite heater, a graphite cover plate for covering the sample slot is provided on the graphite heater, and the graphite cover plate and the slot wall of the sample slot are penetrated by serrated grooves, graphite electrodes are symmetrically electrically connected to the graphite heater, a water-cooled electrode is detachably installed on the end of the graphite electrode away from the graphite heater, a connecting block is locked and fixed on the water-cooled electrode, and the connecting block is powered by an external power supply via a cable.

[0006] Preferably, the two ends of the water-cooled electrode form a circular water channel through a water-cooled sealing plate and an insulating plate, the upper end surface of the water-cooled electrode is provided with a water outlet, and the lower end surface of the water-cooled electrode is provided with a water inlet. By connecting the water outlet and the water inlet to an external water cooler, the deionized water in the circular water channel is circulated and cooled.

[0007] Preferably, a plurality of countersunk positioning holes are correspondingly provided on the end surfaces of the water-cooled sealing plate and the water-cooled electrode, and the water-cooled sealing plate and the insulating plate are fixedly mounted on the water-cooled electrode by locking screws and insulating washers.

[0008] Preferably, a first sealing ring is provided between the end surfaces of the water-cooled sealing plate and the water-cooled electrode that contact each other, and a second sealing ring is filled and arranged between the end surfaces of the insulating plate and the water-cooled electrode that contact each other.

[0009] Preferably, a connecting block is slidably plugged into the water-cooled electrode, a threaded connecting hole is provided on the connecting block, a connecting bolt is threadedly connected in the threaded connecting hole, and the connecting bolt is used to squeeze and lock the connecting block to the water-cooled electrode.

[0010] Preferably, one end of the graphite electrode extends out of the graphite heater and is threadedly connected to a graphite nut, and the other end is threadedly connected to the middle part of the water-cooled electrode. The graphite cover plate is fixedly connected to the graphite heater via a graphite bolt.

[0011] Preferably, the serrated groove is divided into a first serrated groove and a second serrated groove, the first serrated groove refers to the serrated groove located on the wall of the sample groove, and the second serrated groove refers to the serrated groove located on the graphite cover plate. The width of the first serrated groove is 2 mm, and the spacing between the first serrated grooves is 16 mm. The width of the second serrated groove is 2 mm, and the spacing between the second serrated grooves is 7 mm.

[0012] Preferably, a vent hole is provided on the water-cooled electrode, and the vent hole leads to one end of the graphite electrode.

[0013] The present invention has the following beneficial effects:

[0014] This heater is used for ultra-high temperature vacuum sintering. By providing correspondingly designed serrated grooves on the graphite heater and the graphite cover plate, when the test sample is electrically heated, the current value passing through each surface of the sample groove of the graphite heater is equal to the current value passing through the graphite cover plate, so that the test sample obtains a more stable and uniform heating effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of a common graphite heater on the market;

[0016] Figure 2 This is a schematic diagram of the overall structure of the graphite heater of the present invention;

[0017] Figure 3 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 4 This is a schematic diagram of a half-section structure of the present invention;

[0019] Figure 5 This is a schematic diagram of the water outlet layout structure of the present invention;

[0020] Figure 6 This is a simulation diagram of the entire graphite heater without a graphite cover plate;

[0021] Figure 7 This is a simulation diagram of the upper surface temperature of the test sample in the graphite heater when no graphite cover plate is added;

[0022] Figure 8 This is a simulation diagram of the lower surface temperature of the test sample in the graphite heater when no graphite cover plate is added;

[0023] Figure 9 This is a simulation diagram of the entire graphite heater when a graphite cover plate is added to the present invention;

[0024] Figure 10 This is a schematic diagram of the simulation of the upper surface temperature of the test sample in the graphite heater when the graphite cover plate is added in the present invention;

[0025] Figure 11 This is a simulation diagram of the upper surface temperature of the test sample in the graphite heater with a graphite cover plate of the present invention;

[0026] Figure 12 This is a physical diagram of the present invention;

[0027] Figure 13 This is a diagram of the sample loading for testing of the present invention;

[0028] Figure 14 This is the actual test diagram after the sample is loaded in the present invention;

[0029] Figure 15 This is a state diagram of the test sample after the test of the present invention is completed.

[0030] In the figure: 1. Graphite heater; 2. Graphite electrode; 3. Water-cooled electrode; 4. Water-cooled sealing plate; 5. First insulating gasket; 6. Locking screw; 7. Second insulating gasket; 8. Insulating plate; 9. First sealing ring; 10. Second sealing ring; 11. Connecting block; 12. Graphite nut; 13. Connecting bolt; 14. Vent; 15. Water outlet; 16. Water inlet; 17. Graphite cover plate; 18. Graphite bolt; 19. Sample slot; 20. First serrated groove; 21. Second serrated groove; 22. Test sample. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] See also Figure 1The present invention provides a technical solution: a heater for ultra-high temperature vacuum sintering, comprising a graphite heater 1, a sample slot 19 being provided in the middle of the graphite heater 1, and characterized in that: a graphite cover plate 17 for covering the sample slot 19 is provided on the graphite heater 1, and the graphite cover plate 17 and the slot wall of the sample slot 19 are both provided with serrated grooves, and graphite electrodes 2 are symmetrically electrically connected to the graphite heater 1, and a water-cooled electrode 3 is detachably installed at one end of the graphite electrode 2 away from the graphite heater 1, and a connecting block 11 is locked and fixed on the water-cooled electrode 3, and the connecting block 11 is powered by an external power supply via a cable. Since most heaters currently on the market are boat-shaped with a large cross-sectional area, their resistance is relatively small, and because graphite expands when heated, it is easily broken by heat at high temperatures, such as Figure 1 As shown;

[0033] In this technical solution, the structure of the graphite heater 11 is optimized. By optimizing the heater structure, the square groove structure is changed to a square groove sawtooth structure, so that the entire heating system is more evenly heated, the heating rate is faster, and the heating temperature is higher. Figure 2 and Figure 6 As shown;

[0034] Compared with the boat-shaped heater of the same size, the graphite heater 1 with serrated grooves has a smaller cross-sectional area and a longer effective length, which greatly improves the overall resistance value of the heater. At the same time, due to the tooth structure, the tooth gap can be compensated to a certain extent when the heater expands at high temperature, effectively avoiding the thermal expansion stress fracture of the heater at high temperature.

[0035] The actual working condition simulation of the graphite heater 1 and the electrode as a whole is carried out, such as Figure 6 As shown in FIG, when the heater structure is simplified and a current load of 300A is applied for 1800S, the required voltage value is 29.1V, and the maximum temperature of the graphite heater 1 can reach 2609.8℃. However, due to the open design of the upper end surface of the graphite heater 11, as shown in FIG. Figure 7 and Figure 8 As shown, the maximum temperature of the lower end surface of the test sample 22 is 2505.5° C., and the maximum temperature of the upper end surface of the test sample 22 is 2438.7° C., resulting in a large temperature difference between various parts of the test sample 22.

[0036] Therefore, the graphite heater 1 needs to be further optimized. Since the temperature difference between the upper and lower end surfaces of the test sample 22 is too large, a graphite cover plate 17 is set on the upper end surface of the graphite heater 1. Through calculation, the width, spacing and number of the serrated grooves on the graphite heater 1 and the graphite cover plate 17 are redesigned.

[0037] In this embodiment, the serrated groove is divided into a first serrated groove 20 and a second serrated groove 21. The first serrated groove 20 refers to the serrated groove located on the groove wall of the sample groove 19, and the second serrated groove 21 refers to the serrated groove located on the graphite cover plate 17. The width of the first serrated groove 20 is 2 mm, and the spacing between the first serrated grooves 20 is 16 mm. The width of the second serrated groove 21 is 2 mm, and the spacing between the second serrated grooves 21 is 7 mm. Under this design, when the test sample 22 is electrically heated, the current value passing through each surface of the sample groove 19 of the graphite heater 1 is equal to the current value passing through the graphite cover plate 17, so that the test sample 22 obtains a more stable and uniform heating effect.

[0038] The actual working condition simulation of the graphite heater 11 and the electrode as a whole is carried out, such as Figure 9 As shown in FIG, when the heater structure is simplified and a current load of 300A is applied for 1800S, the required voltage value is 22.4V, and the maximum temperature of the graphite heater 11 can reach 2525.9°C. Figure 10 and Figure 11 As shown, the maximum temperature of the lower end surface of the test sample 22 is 2504.0°C, and the maximum temperature of the upper end surface of the test sample 22 is 2504.0°C, so that the test sample 2222 obtains a more stable and uniform heating effect.

[0039] In this embodiment, the two ends of the water-cooled electrode 3 form a circular water channel through the water-cooled sealing plate 4 and the insulating plate 8. The upper end surface of the water-cooled electrode 3 is provided with a water outlet 15, and the lower end surface of the water-cooled electrode 3 is provided with a water inlet 16. By connecting the water outlet 15 and the water inlet 16 to an external water cooler, the deionized water in the circular water channel is circulated and cooled.

[0040] like Figure 3 and Figure 4 As shown, in this technical solution, the annular water channel is provided to circulate and cool the deionized water outside the water-cooled electrode 3 to prevent the water-cooled electrode 3 from being overheated and damaged.

[0041] In this embodiment, a plurality of countersunk positioning holes are correspondingly provided on the end faces of the water-cooled sealing plate 4 and the water-cooled electrode 3 , and the water-cooled sealing plate 4 and the insulating plate 8 are both fixedly mounted on the water-cooled electrode 3 by locking screws 6 and insulating gaskets.

[0042] When actually installing the application, Figure 3 and Figure 4As shown, a circular water channel is provided at the center of the rear end face of the water-cooled electrode 3, and the water-cooled electrode 3 located at the rear side of the circular water channel is slidably connected to a water-cooled sealing plate 4, and a first countersunk positioning hole is provided on the rear end face of the water-cooled sealing plate 4, and a first insulating gasket 5 is placed in each of the first countersunk positioning holes of the water-cooled sealing plate 4, and a locking screw 6 passes through the first insulating gasket 5 and is threadedly fixed to the water-cooled electrode 3, and a second countersunk hole is provided on the front end face of the water-cooled electrode 3, and a second insulating gasket 7 is placed in the second countersunk positioning hole of the water-cooled electrode 3, and the locking screw 6 passes through the second insulating gasket 7 and is fixedly connected to the insulating plate 8.

[0043] In this embodiment, a first sealing ring 9 is provided between the contacting end surfaces of the water-cooled sealing plate 4 and the water-cooled electrode 3, and a second sealing ring 10 is provided between the contacting end surfaces of the insulating plate 8 and the water-cooled electrode 3. Figure 4 As shown, the front end surface of the water-cooled sealing plate 4 defines a first sealing ring groove, within which a first sealing ring 9 is disposed. The front end surface of the water-cooled electrode 3 defines a second sealing ring groove, within which a second sealing ring 10 is disposed. The arrangement of the first sealing ring 9 and the second sealing ring 10 seals the waterway within the water-cooled electrode 3, preventing leakage of deionized water within the waterway. In actual application, both the first sealing ring 9 and the second sealing ring 10 are made of fluoropolymer O-rings.

[0044] In this embodiment, a connecting block 11 is slidably inserted into the water-cooled electrode 3 . A threaded connection hole is provided on the connecting block 11 . A connecting bolt 13 is threadedly connected in the threaded connection hole. The connecting bolt 13 is used to squeeze and lock the connecting block 11 to the water-cooled electrode 3 .

[0045] like Figure 4 As shown, in this embodiment, one end of the graphite electrode 2 extends out of the graphite heater 1 and is threadedly connected to the graphite nut 12, and the other end is threadedly connected to the middle part of the water-cooled electrode 3, and the graphite cover plate 17 is fixedly connected to the graphite heater 1 by a graphite bolt 18. By adopting fasteners made of graphite material, it is easy to ensure that the current is relatively uniform in all parts of the heater, thereby ensuring the overall heating effect. In specific applications, graphite paper needs to be placed on the front and rear end surfaces of the graphite heater 1 located in the mounting hole to ensure good contact between the graphite heater 1 and the graphite electrode 2 and the graphite nut 12, and to ensure that the current values ​​passing through each surface of the sample slot 19 of the graphite heater 1 are equal to the current values ​​passing through the graphite cover plate 17, so that the test sample 22 obtains a more stable and uniform heating effect.

[0046] Since graphite has self-lubricating properties, it will produce a self-sealing effect when threaded. If the air vent 14 is not opened at the water-cooled electrode 3, the graphite electrode 2 cannot be screwed into the inner cavity of the water-cooled electrode 3 due to the air pressure between the water-cooled electrode 3 and one end of the graphite electrode 2. Figure 4 As shown, in this embodiment, a vent hole 14 is provided on the water-cooled electrode 3 , and the vent hole 14 leads to one end of the graphite electrode 2 .

[0047] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations. The phrase "includes an element defined by..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0048] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A heater for ultra-high temperature vacuum sintering, comprising a graphite heater, wherein a sample slot is provided in the middle of the graphite heater, and wherein: The graphite heater is provided with a graphite cover plate for covering the sample slot, and the graphite cover plate and the slot wall of the sample slot are both provided with serrated grooves. The graphite heater is symmetrically electrically connected to graphite electrodes, and a water-cooled electrode is detachably installed at one end of the graphite electrode away from the graphite heater. A connecting block is locked and fixed on the water-cooled electrode, and the connecting block is powered by an external power supply via a cable.

2. The heater for ultra-high temperature vacuum sintering according to claim 1, characterized in that: The two ends of the water-cooled electrode form a circular water channel through a water-cooled sealing plate and an insulating plate. A water outlet is provided on the upper end surface of the water-cooled electrode, and a water inlet is provided on the lower end surface of the water-cooled electrode. By connecting the water outlet and the water inlet to an external water cooler, the deionized water in the circular water channel is circulated and cooled.

3. The heater for ultra-high temperature vacuum sintering according to claim 2, characterized in that: The end surfaces of the water-cooled sealing plate and the water-cooled electrode are respectively provided with a plurality of countersunk positioning holes. The water-cooled sealing plate and the insulating plate are both fixedly mounted on the water-cooled electrode by locking screws and insulating washers.

4. The heater for ultra-high temperature vacuum sintering according to claim 3, characterized in that: A first sealing ring is provided between the end surfaces of the water-cooled sealing plate and the water-cooled electrode that contact each other, and a second sealing ring is filled and arranged between the end surfaces of the insulating plate and the water-cooled electrode that contact each other.

5. The heater for ultra-high temperature vacuum sintering according to claim 2, characterized in that: A connecting block is slidably plugged into the water-cooled electrode. The connecting block is provided with a threaded connecting hole. A connecting bolt is threadedly connected in the threaded connecting hole. The connecting bolt is used to squeeze and lock the connecting block to the water-cooled electrode.

6. The heater for ultra-high temperature vacuum sintering according to claim 1 or 2, characterized in that: One end of the graphite electrode extends out of the graphite heater and is threadedly connected to a graphite nut, and the other end is threadedly connected to the middle part of the water-cooled electrode. The graphite cover plate is fixedly connected to the graphite heater through a graphite bolt.

7. The heater for ultra-high temperature vacuum sintering according to claim 1 or 2, characterized in that: The serrated grooves are divided into first serrated grooves and second serrated grooves. The first serrated grooves refer to the serrated grooves located on the wall of the sample groove, and the second serrated grooves refer to the serrated grooves located on the graphite cover plate. The width of the first serrated grooves is 2 mm, and the spacing between the first serrated grooves is 16 mm. The width of the second serrated grooves is 2 mm, and the spacing between the second serrated grooves is 7 mm.

8. The heater for ultra-high temperature vacuum sintering according to claim 1 or 2, characterized in that: A vent hole is provided on the water-cooled electrode, and the vent hole leads to one end of the graphite electrode.

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