Induction furnace capable of being accurately positioned and opened

Abstract

The invention relates to an induction furnace capable of being accurately positioned and opened, and belongs to the technical field of silicon carbide preparation. The induction furnace comprises a furnace chamber, the top of the furnace chamber is provided with an upper flange, and the bottom of the furnace chamber is provided with a lower flange; the crucible is arranged in the furnace chamber; the outer thermal insulation and the lower thermal insulation form a thermal insulation layer, the thermal insulation layer is arranged outside the crucible, and a movable supporting rod is fixed at the bottom of the lower thermal insulation; the moving mechanism is arranged at the top of the lower flange, the moving mechanism comprises a plane moving assembly, and the plane moving assembly can drive the movable supporting rod to drive the heat preservation layer to move; and the closable sliding rail is arranged at the top of the furnace chamber, and a movable laser positioner is arranged on the closable sliding rail. The induction furnace capable of being accurately positioned and opened can ensure that the crucible and the heat preservation felt are accurately positioned in the assembly process, and an air layer between the crucible and the heat preservation felt is more uniform, so that a temperature field is uniform and stable, the influence of temperature field disturbance on SiC growth is reduced, and the product quality is improved.

Description

Technical Field

[0001] The present application relates to an induction furnace with precise positioning and installation, belonging to the technical field of silicon carbide preparation. Background Art

[0002] At present, the induction furnaces on the market are mostly used to grow SiC through the PVT method. The principle is to use alternating current to pass through the multi-turn induction coil on the induction furnace outside the graphite crucible to form an induced magnetic field of the same frequency in the crucible, thereby generating an induced electromotive force. The high-purity graphite crucible material has good conductivity, so it will generate induced current on the crucible wall to form eddy currents, and produce a skin effect under the action of the Lorentz force, so that the induced current converges on the outer wall of the crucible and generates Joule heat, and is heated as a heat source in the furnace cavity through heat convection, heat radiation and heat conduction. In addition, it is necessary to use insulation felt on the outer layer to prevent excessive heat loss, so as to achieve high-temperature growth of SiC crystals in the crucible.

[0003] During the growth of SiC, the gas source is generated by continuously heating the carbon powder, silicon powder and SiC powder at the bottom of the crucible, and is transmitted from the bottom of the crucible to the top of the crucible along with the flow field and the thermal field to achieve growth on the seed crystal. Since Si atmosphere easily reacts with graphite to generate SiC, the hard felt carbon fiber and soft felt chopped fibers in the insulation felt are easy to react with Si atmosphere. During the crystal growth process, the Si atmosphere overflows through the gap of the crucible and reacts with the insulation felt to easily form SiC polycrystals, thereby corroding the insulation felt and affecting the insulation effect, resulting in uneven thermal field or poor insulation effect during the crystal growth process, affecting product quality.

[0004] On the other hand, during the assembly process, there are also problems such as uneven heating of the crucible and uneven air layer between the crucible and the insulation felt due to inaccurate positioning of the crucible and insulation felt. This will cause different degrees of erosion at different positions of the crucible, resulting in uneven temperature field, and then causing temperature field disturbances that ultimately affect the growth quality of SiC.

[0005] Based on the problems in the prior art, it is necessary to provide an induction furnace that can be accurately positioned and installed to ensure the stability and uniformity of the temperature field during the SiC growth process, thereby ensuring the growth quality of SiC. Summary of the invention

[0006] In order to solve the above problems, an induction furnace with precise positioning and installation is provided, which can ensure the accurate positioning of the crucible and the insulation felt during the assembly process, so that the air layer between the crucible and the insulation felt is more uniform, thereby ensuring a uniform and stable temperature field, reducing the influence of temperature field disturbance on SiC growth, and thus improving product quality.

[0007] According to one aspect of the present application, there is provided an induction furnace with precise positioning and installation, the induction furnace comprising:

[0008] A furnace chamber, wherein an upper flange is arranged on the top of the furnace chamber, and a lower flange is arranged on the bottom of the furnace chamber;

[0009] A crucible, wherein the crucible is arranged in the furnace chamber;

[0010] External insulation and lower insulation, the external insulation and the lower insulation form an insulation layer, the insulation layer is arranged on the outside of the crucible, and a movable support rod is fixed to the bottom of the lower insulation;

[0011] A motion mechanism, the motion mechanism is arranged on the top of the lower flange, the motion mechanism comprises a plane moving component, the plane moving component can drive the movable support rod to drive the thermal insulation layer to move;

[0012] A closable slide rail is arranged on the top of the furnace cavity and a movable laser locator is provided on the closable slide rail.

[0013] Optionally, the planar moving assembly includes a transverse moving portion and a longitudinal moving portion; the longitudinal moving portion is used to control the longitudinal movement of the movable support rod; and the transverse moving portion is used to control the transverse movement of the movable support rod.

[0014] Optionally, the motion mechanism further includes a rotation component, and the rotation component is used to control the rotation of the movable support rod.

[0015] Optionally, the motion mechanism further includes a lifting component, and the lifting component is used to control the raising or lowering of the movable support rod.

[0016] Optionally, the enclosable slide rail includes a transverse slide rail and a longitudinal slide rail, and both the transverse slide rail and the longitudinal slide rail are provided with a movable laser locator.

[0017] Optionally, a crucible holder is fixed to the bottom of the upper flange, and the crucible comprises a transitional crucible cover and a crucible body, and the crucible body is fixed to the crucible holder through the transitional crucible cover.

[0018] Optionally, the transitional crucible cover is located between the crucible holder and the crucible body, and is respectively connected to the crucible holder and the crucible body through threads.

[0019] Optionally, the bottom of the crucible holder is provided with an internal thread, the top of the transitional crucible cover is provided with an external thread that cooperates with the internal thread of the bottom of the crucible holder, the bottom of the transitional crucible cover is provided with an internal thread, and the top of the crucible body is provided with an external thread that cooperates with the internal thread of the bottom of the transitional crucible cover.

[0020] Optionally, the bottom of the crucible holder is provided with an external thread, the top of the transitional crucible cover is provided with an internal thread that cooperates with the external thread of the bottom of the crucible holder, the bottom of the transitional crucible cover is provided with an external thread, and the top of the crucible body is provided with an internal thread that cooperates with the external thread of the bottom of the transitional crucible cover.

[0021] Optionally, a graphitized carbon fiber cloth is further arranged between the outer insulation and the crucible, the graphitized carbon fiber cloth includes a matrix and carbon fiber bundles in the matrix, the matrix is ​​tar pitch, the carbon fiber bundles are graphitized carbon fiber bundles, and the graphitized carbon fiber bundles are arranged in parallel in the tar pitch matrix.

[0022] Optionally, the angle between the graphitized carbon fiber bundle and the short side of the graphitized carbon fiber cloth is

[0023] Optional, Optional,

[0024] in The size of will affect the angle at which the carbon fiber bundle cuts the magnetic flux lines, thus affecting the amount of Joule heat generated on the carbon fiber surface. When the size is within an appropriate range, the heat generated by the graphitized carbon fiber cloth can be reduced, thereby reducing the degree of reaction between the graphitized carbon fiber cloth and the Si atmosphere, thereby increasing the service life of the graphitized carbon fiber cloth.

[0025] Optionally, the spacing between the graphitized carbon fiber bundles is d, 0.5 mm ≤ d ≤ 5.0 mm;

[0026] Optional, 1.5mm≤d≤2.0mm.

[0027] The size of d will affect the shielding effect of graphitized carbon fiber on electromagnetic signals. If d is too large, the electromagnetic signal shielding effect is poor, and the density of the graphitized carbon fiber bundle is low. The Si atmosphere is more likely to react with tar pitch, and the shielding effect of the graphitized carbon fiber bundle is poor, resulting in more serious erosion of the Si atmosphere on the tar pitch, reducing the service life of the graphitized carbon fiber cloth; if d is too small, the graphitized carbon fiber bundle is prone to adhesion in the preparation process, resulting in changes in the angle at which the graphitized carbon fiber bundle cuts the magnetic flux lines. The increase in magnetic flux increases the calorific value of the graphitized carbon fiber cloth, and if d is too small, there is also the problem of a large amount of graphitized carbon fiber bundles used and a high cost; and when the size of d is within an appropriate range, it has a good electromagnetic signal shielding effect, at which time the calorific value of the graphitized carbon fiber cloth can be reduced, thereby reducing the degree of reaction between the graphitized carbon fiber cloth and the Si atmosphere, thereby increasing the service life of the graphitized carbon fiber cloth.

[0028] Optionally, the graphitized carbon fiber bundles are arranged in parallel to form a braided layer, and the graphitized carbon fiber cloth includes L braided layers arranged in parallel, 1≤L≤5;

[0029] Optional, 2≤L≤3.

[0030] If the size of L is too small, the shielding effect of the graphitized carbon fiber cloth on the Si atmosphere is poor, which makes it easy for the Si atmosphere to penetrate the tar pitch and corrode the thermal insulation felt. If L is too large, on the one hand, the cost will increase, and on the other hand, the large number of carbon fiber bundle weaving layers will easily cause a stronger skin effect on the carbon fiber surface, generating eddy currents on the surface and increasing the heat generation, resulting in a reduced life of the graphitized carbon fiber cloth.

[0031] Optionally, the spacing of the braided layers is D, 1.5mm≤D≤2.0mm.

[0032] The size of D will affect the heat generation of the graphitized carbon fiber cloth. If D is too large, the thickness of the graphitized fiber cloth will increase. After the thickness increases, the transmittance of the magnetic flux lines decreases, resulting in more absorption, and it is easier to reflect inside the graphitized carbon fiber cloth, resulting in increased heat generation. If D is too small, the carbon fiber bundles are more likely to adhere during processing and the shielding effect of the carbon fiber cloth will deteriorate.

[0033] It should be noted that the present application does not limit the preparation method of the graphitized carbon fiber cloth. For example, when the graphitized carbon fiber cloth includes multiple parallel woven layers, all the woven layers can be pre-impregnated with tar pitch at the same time, or they can be pre-impregnated layer by layer and then bonded together, and the thickness of the layer after pre-impregnation can be controlled to be close to the spacing D between the woven layers.

[0034] The beneficial effects of this application include but are not limited to:

[0035] 1. According to the precise positioning induction furnace of the present application, the inner edge of the external insulation and the inner edge of the crucible can be determined by setting a movable laser locator, thereby determining the distance of the cavity between the inner edge of the external insulation and the inner edge of the crucible, and then adjusting the external insulation through a planar moving component to ensure that the distance between the inner edge of the external insulation and the inner edge of the crucible is uniform, and to ensure that the temperature field is uniform and stable, thereby reducing the influence of temperature field disturbance on SiC growth and improving product quality.

[0036] 2. According to the precise positioning induction furnace of the present application, further setting a rotating component can improve the sampling point position of the movable laser locator, thereby improving the uniformity of the distance between the inner edge of the outer insulation and the inner edge of the crucible, and further improving the uniformity and stability of the temperature field.

[0037] 3. According to the precise positioning and installation of the induction furnace of the present application, the crucible body can be stably fixed at the fixed position of the upper flange through the crucible fixer in conjunction with the transition crucible cover, and the insulation layer can be moved in conjunction with the lifting assembly to adjust the relative position with the crucible body, thereby meeting the needs of SiC crystal growth.

[0038] 4. According to the precise positioning and installed induction furnace of the present application, a graphitized carbon fiber cloth is arranged between the insulation felt and the crucible, which can capture the Si atmosphere overflowing from the crucible and preferentially form SiC polycrystals on the surface of the graphitized carbon fiber cloth, thereby improving the erosion of the Si atmosphere on the insulation felt when preparing SiC crystals by the PVT method, thereby ensuring the insulation effect of the insulation felt and the uniformity and stability of the temperature field, thereby reducing the generation of polymorphism and improving the crystal quality.

[0039] 5. According to the precise positioning and installation induction furnace of the present application, by improving the structure of the graphitized carbon fiber bundle in the graphitized carbon fiber cloth, it is possible to ensure the protective effect of the graphitized carbon fiber cloth on the thermal insulation felt while improving the service life of the graphitized carbon fiber cloth itself, and it has good reusability. It also makes the graphitized carbon fiber cloth have good high temperature resistance and tensile strength, which can meet the use environment of more than 2000°C during the growth of silicon carbide. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0041] Figure 1 This is a schematic diagram of the structure of the induction furnace with precise positioning and installation involved in Example 1 of the present application;

[0042] Figure 2 This is a schematic diagram of the structure of the braided layer in the graphitized carbon fiber cloth involved in Example 2 of the present application;

[0043] Figure 3 This is a schematic diagram of the arrangement of graphitized carbon fiber bundles in a woven layer of the graphitized carbon fiber cloth involved in Example 2 of the present application.

[0044] List of parts and reference numerals:

[0045] 1-furnace chamber; 2-upper flange; 3-lower flange; 4-crucible body; 5-transition crucible cover; 6-crucible holder; 7-external insulation; 8-lower insulation; 9-movable support rod; 10-movable laser positioner; 11-transverse slide rail; 12-transverse rail; 13-graphitized carbon fiber cloth; 14-transverse moving part; 15-longitudinal moving part; 16-lifting assembly; 17-rotating assembly; 18-temperature measuring hole; 19-induction coil. DETAILED DESCRIPTION

[0046] The present application is described in detail below in conjunction with examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials in the examples of the present application are purchased through commercial channels.

[0047] The present application scheme is described below through specific embodiments.

[0048] Example 1

[0049] like Figure 1 As shown, according to one aspect of the present application, there is provided an induction furnace with precise positioning and installation, the induction furnace comprising a furnace chamber 1 and an upper flange 2 on the top of the furnace chamber 1, and a lower flange 3 on the bottom of the furnace chamber 1; a crucible, an outer insulation 7 and a lower insulation 8 are arranged in the furnace chamber 1; the outer insulation 7 and the lower insulation 8 form an insulation layer, the crucible is arranged inside the insulation layer, a movable support rod 9 is fixed to the bottom of the lower insulation 8, a moving mechanism is arranged on the top of the lower flange 3, the moving mechanism comprises a planar moving component, the planar moving component can drive the movable support rod 9 to drive the insulation layer to move, a closeable slide rail is arranged on the top of the furnace chamber 1, and a movable laser locator 10 is arranged on the closeable slide rail.

[0050] The movable laser locator 10 can move along the enclosed slide rail. The laser locator can determine the outer edge of the crucible and the inner edge of the outer insulation 7 by measuring the round-trip time and combining the distance relationship and then comparing the changing trend of the round-trip time, wherein the outer insulation 7 is the insulation felt, thereby determining the cavity width between the outer insulation 7 and the crucible, and then controlling the planar moving component in the motion mechanism according to the determined cavity width. The planar moving component can control the movable support rod 9 to drive the insulation layer to move, thereby driving the outer insulation 7 to move, and then the width of the cavity between the inner edge of the outer insulation 7 and the outer edge of the crucible can be adjusted to be similar, thereby ensuring the uniformity of the temperature field, reducing the influence of the temperature field disturbance on the growth of SiC, and thus ensuring the quality of SiC products.

[0051] The present application does not limit the implementation method of the plane moving assembly, as long as it can drive the movable support rod 9 to move and adjust in the plane. For example, as an implementation method, the plane moving assembly includes a transverse moving part 14 and a longitudinal moving part 15; the longitudinal moving part 15 is used to control the longitudinal movement of the movable support rod 9; the transverse moving part 14 is used to control the transverse movement of the movable support rod 9.

[0052] It should be noted that the closable slide rail in the present application is a closable type and can be used to protect the movable laser locator 10 and the slide rail. It is opened before crystal growth to allow the movable laser locator 10 to work, and is closed during the crystal growth process, thereby protecting the movable laser locator 10 and the slide rail and preventing them from being affected by the Si atmosphere or SiC atmosphere during the crystal growth process and affecting their subsequent normal operation.

[0053] As a specific implementation, the lower flange 3 is provided with a longitudinal track, and the longitudinal moving part 15 can move longitudinally along the longitudinal track provided on the lower flange 3 under the action of the driving mechanism. Further, the longitudinal moving part 15 is provided with a transverse track 12, and the transverse moving part 14 can move transversely along the transverse track 12 provided on the longitudinal moving part 15 under the action of the driving mechanism, and then drive the movable support rod 9 to move. Through the cooperation of the transverse moving part 14 and the longitudinal moving part 15, the movable support rod 9 can be moved in a plane, thereby driving the movement of the outer insulation 7 to adjust the relative position with the crucible. In addition, the skilled and technical personnel can understand that the order of setting the longitudinal moving part 15 and the transverse moving part 14 can be exchanged. It is only necessary to set the transverse track 12 corresponding to the lower flange 3, and the transverse moving part 14 moves on this transverse track 12, and then set the longitudinal track on the transverse moving part 14, and the longitudinal moving part 15 moves on this longitudinal track, so as to achieve the same function.

[0054] As an implementation mode, the motion mechanism further includes a rotating assembly 17 and a lifting assembly 16; the rotating assembly 17 is used to control the rotation of the movable support rod 9; and the lifting assembly 16 is used to control the movable support rod 9 to rise or fall.

[0055] By setting the rotating component 17, the movable support rod 9 can be rotated, thereby driving the rotation of the external insulation 7. Since the external insulation 7 is easily corroded by the Si atmosphere, its inner edge may change, thereby affecting the cavity distance between the inner edge of the external insulation 7 and the outer edge of the crucible. After the external insulation 7 is set to be rotatable, the movable laser positioner 10 can measure and adjust more radial directions of the external insulation 7, thereby ensuring that the uniformity of the cavity distance between the inner edge of the external insulation 7 and the outer edge of the crucible is more accurate, thereby further improving the uniformity of the temperature field.

[0056] By providing the lifting assembly 16 , the rise or fall of the thermal insulation layer can be controlled, thereby meeting different requirements for the thermal insulation layer during the SiC crystal growth process.

[0057] The present application does not impose any specific limitation on the implementation method of the rotating assembly 17 and the lifting assembly 16, which can be conventionally selected by those skilled in the art. There is no specific limitation on the connection method between the rotating assembly 17, the lifting assembly 16 and the planar moving assembly. For example, the planar moving assembly is arranged at the bottom, the lifting assembly 16 is arranged in the middle, and the rotating assembly 17 is arranged at the top, or the structural order of the three is swapped as long as the effect required by the present application can be normally met. Those skilled in the art can perform conventional implementation or make adjustments and solutions based on some problems that arise.

[0058] As an implementation mode, the closable slide rail includes a transverse slide rail 11 and a longitudinal slide rail, and a movable laser locator 10 is disposed on both the transverse slide rail 11 and the longitudinal slide rail.

[0059] By setting two slide rails, the number of movable laser locators 10 thereon can be increased, thereby improving the efficiency of determining the outer edge of the crucible and the inner edge of the outer insulation 7. At the same time, several movable laser locators 10 work at the same time, which can significantly improve the efficiency of adjusting the cavity distance between the outer edge of the crucible and the inner edge of the outer insulation 7.

[0060] As an implementation mode, a crucible holder 6 is fixed to the bottom of the upper flange 2, and the crucible includes a transitional crucible cover 5 and a crucible body 4;

[0061] The transitional crucible cover 5 is located between the crucible holder 6 and the crucible body 4 , and is respectively connected to the crucible holder 6 and the crucible body 4 through threads.

[0062] As a specific implementation manner, the bottom of the crucible holder 6 is provided with an internal thread, the top of the transitional crucible cover 5 is provided with an external thread that cooperates with the internal thread at the bottom of the crucible holder 6, the bottom of the transitional crucible cover 5 is provided with an internal thread, and the top of the crucible body 4 is provided with an external thread that cooperates with the internal thread at the bottom of the transitional crucible cover 5.

[0063] As another specific embodiment, the bottom of the crucible holder 6 is provided with an external thread, the top of the transition crucible cover 5 is provided with an internal thread that cooperates with the external thread at the bottom of the crucible holder 6, the bottom of the transition crucible cover 5 is provided with an external thread, and the top of the crucible body 4 is provided with an internal thread that cooperates with the external thread at the bottom of the transition crucible cover 5.

[0064] The skilled person and technicians know that since the intermediate transition crucible cover 5 is respectively connected to the upper and lower crucible holders 6 and the crucible body 4 by threads, there are other different implementation methods, and the skilled person and technicians can design them according to needs.

[0065] It should be noted that the skilled and technical personnel can adjust the shapes of the transition crucible cover 5, the crucible holder 6 and the crucible body 4 according to the situation to meet the technical effect to be achieved by the present application. For example, since the movable laser locator 10 needs to meet the positioning of the outer edge of the crucible body 4, the outer edges of the transition crucible cover 5 and the crucible holder 6 cannot block the positioning of the outer edge of the crucible body 4 by the movable laser locator 10, so the corresponding threaded connection structure can be designed according to the needs. For example, in the case where the bottom of the transition crucible cover 5 is provided with an internal thread, and the top of the crucible body 4 is provided with an external thread that matches the internal thread at the bottom of the transition crucible cover 5, in order to meet the positioning needs of the above-mentioned movable laser locator 10, a narrowed transition structure can be provided on the top of the crucible body 4, and then the outer edge of the transition crucible cover 5 can be set so that it cannot block the outer edge of the crucible body 4.

[0066] The crucible holder 6 is fixed on the bottom of the upper flange 2, and the crucible body 4 and the crucible holder 6 are respectively connected through the transition crucible cover 5. After the reaction materials are filled into the crucible body 4, the crucible body 4 can be fixed at a fixed position of the upper flange 2, and then the relative position of the external insulation 7 can be adjusted.

[0067] As an embodiment, a graphitized carbon fiber cloth 13 is also arranged between the outer insulation 7 and the crucible. The graphitized carbon fiber cloth 13 includes a matrix and carbon fiber bundles in the matrix. The matrix is ​​tar pitch, and the carbon fiber bundles are graphitized carbon fiber bundles. The graphitized carbon fiber bundles are arranged in parallel in the tar pitch matrix.

[0068] Tar pitch is the binder, and graphitized carbon fiber bundles are the support. Since Si atmosphere is more easily captured by the tar pitch binder, it can effectively reduce the erosion of Si atmosphere on the insulation felt during the preparation of silicon carbide crystals by the PVT method, thereby ensuring the insulation effect of the insulation felt, ensuring the uniformity and stability of the temperature field during the crystal growth process, and reducing the generation of polymorphism. The support is a graphitized carbon fiber bundle, which can significantly improve the tensile strength and high temperature resistance of the carbon fiber cloth, and can meet the use environment of more than 2000°C during the growth of silicon carbide.

[0069] It should be noted that the tar pitch and graphitized carbon fiber bundles used in the present application are commonly used materials, and those skilled in the art can select them according to their needs. In addition, the present application does not limit the preparation process of the graphitized carbon fiber cloth 13, and the commonly used preparation process in the field can be adopted, and the prepreg method can also be adjusted according to needs.

[0070] It should be noted that the present application scheme mainly describes the main invention points. Other structures in the induction furnace can be implemented by referring to the scheme of the induction furnace in the field. This is something that can be routinely determined by those skilled in the art and does not require additional elaboration. For example, those skilled in the art can set the deployment mode of the induction coil 19 as needed, and can also set the temperature measuring hole 18 structure on the upper flange 2 as needed. In addition, those skilled in the art can also adjust and set the position of the closable slide rail and the crucible holder 6 on the upper flange 2 as needed, and adjust the shape of the transition crucible cover 5 as needed, so that the movable laser positioner 10 on the closable slide rail can have sufficient movement space and can detect the outer edge of the crucible body 4 and the inner edge of the outer insulation 7. This is a routine skill of those skilled in the art and does not require additional explanation.

[0071] The scheme of the graphitized carbon fiber cloth 13 is described in detail below.

[0072] Example 2

[0073] like Figure 2 and Figure 3 As shown, the present application provides a graphitized carbon fiber cloth 13, which includes a matrix and carbon fiber bundles in the matrix, the matrix is ​​tar pitch, the carbon fiber bundles are graphitized carbon fiber bundles, and the graphitized carbon fiber bundles are arranged in parallel in the tar pitch matrix.

[0074] The angle between the graphitized carbon fiber bundle and the short side of the graphitized carbon fiber cloth 13 is In an alternative embodiment, In another alternative embodiment In another alternative embodiment The spacing of the graphitized carbon fiber bundles is d, and in one optional embodiment, 0.5 mm ≤ d ≤ 5.0 mm, and in another optional embodiment, 1.5 mm ≤ d ≤ 2.0 mm. The graphitized carbon fiber bundles are arranged in parallel to form a braided layer, and the graphitized carbon fiber cloth 13 includes L braided layers arranged in parallel, and in one optional embodiment, 1 ≤ L ≤ 5, and in another optional embodiment, 2 ≤ L ≤ 3. The spacing of the braided layers is D, and in one optional embodiment, 1.5 mm ≤ D ≤ 2.0 mm.

[0075] The product after the graphitized carbon fiber cloth 13 is prepared is in the form of a roll similar to conventional cloth, wherein the width of the roll is the short side of the graphitized carbon fiber cloth 13, and the extension direction of the roll is the long side of the graphitized carbon fiber cloth 13, based on which technicians in this field can accurately determine the long side and short side of the graphitized carbon fiber cloth 13.

[0076] Example 3

[0077] The specific structural parameters of the graphitized carbon fiber cloth 13 samples 1 to 16 are shown in Table 1 below. Except for the different structural parameters in Table 1, other conditions of the graphitized carbon fiber cloth 13 samples 1 to 16 are the same.

[0078] Table 1 Structural parameters of graphitized carbon fiber cloth 13 of samples 1 to 16

[0079]

[0080] Performance tests were performed on samples 1 to 16 of the graphitized carbon fiber cloth 13 in Table 1, including service life performance, thermal insulation felt protection effect performance, tensile strength performance, and the influence on the qualified rate of crystal growth during the preparation process of the PVT method, wherein the tensile strength unit is MPa, and the test complies with the test regulations for the mechanical performance indicators of carbon fiber cloth in the Chinese standard GB50367-2013, wherein the tensile test was performed along the short side direction of the graphitized carbon fiber cloth 13; wherein the test conditions for service life performance, thermal insulation felt protection effect performance, and qualified rate of crystal growth were carried out under the same conditions for growing SiC crystals by the PVT method, and the measurement and counting were performed after the crystal growth was completed. The service life performance, the protection effect performance of the thermal insulation felt, and the qualified rate of crystal growth are calculated, wherein the service life performance is characterized by the weight loss rate of the graphitized carbon fiber cloth 13, and the unit is %, the weight loss rate of the graphitized carbon fiber cloth 13 = (the weight of the graphitized carbon fiber cloth 13 before crystal growth - the weight of the graphitized carbon fiber cloth 13 after the end) / the weight of the graphitized carbon fiber cloth 13 before crystal growth * 100%; wherein the protection effect performance of the thermal insulation felt is characterized by the weight loss rate of the thermal insulation felt, and the unit is %, the weight loss rate of the thermal insulation felt = (the weight of the thermal insulation felt before crystal growth - the weight of the thermal insulation felt after the end) / the weight of the thermal insulation felt before crystal growth * 100%; wherein the qualified rate of crystal growth = (the number of crystals excluding polymorphs) / the total number of crystals * 100%.

[0081] Among them, the PVT method crystal growth process includes the following steps: 1) preparing graphite material and silicon carbide powder raw materials and placing them in a crucible; 2) wrapping the graphitized carbon fiber cloth 13 on the outside of the crucible, and the short side direction of the graphitized carbon fiber cloth 13 is parallel to the axial direction of the crucible during wrapping, and then putting the wrapped crucible into an induction furnace, and there is also insulation felt on the outside of the wrapped crucible; 3) putting in a seed crystal to start crystal growth, specifically including: S1, maintaining the pressure at 50mbar, heating rate at 5℃ / min, temperature rising to 2100℃, and maintaining time for 10h; S2, reducing the pressure to 5mbar, reducing the pressure at a rate of 0.2mbar / min, maintaining the temperature at 2200℃, stabilizing for 5h after reducing the pressure, and the temperature during stabilization is at 2250℃; S3, the growth process temperature is 2300℃, and the growth time is 50h.

[0082] During the PVT crystal growth process, except for the different graphitized carbon fiber cloth 13 used, other conditions were controlled to be the same. After the end, the service life performance, thermal insulation felt protection effect performance, and tensile strength performance of the graphitized carbon fiber cloth 13 samples 1 to 16 were measured and calculated. The results are shown in Table 2 below.

[0083] Table 2 Performance test results of graphitized carbon fiber cloth 13 samples 1 to 16

[0084]

[0085]

[0086] Using the same PVT method crystal growth conditions as above, when the graphitized carbon fiber cloth 13 is not set, the weight loss rate of the insulation felt is 23%, and the qualified rate of crystal growth is 74%. Further combined with the results in Table 2, it can be seen that by setting the graphitized carbon fiber cloth 13, the erosion of the Si atmosphere on the insulation felt during the crystal growth process can be significantly improved, thereby ensuring the insulation effect of the insulation felt during the crystal growth process, making the temperature field more uniform and stable during the crystal growth process, thereby effectively reducing the occurrence of polymorphism and improving the crystal quality. Further according to the results in Table 2, it can be seen that samples 1 to 4 not only have a good insulation felt protection effect, but also the graphitized carbon fiber cloth 13 has a better service life and good reusability.

[0087] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. An induction furnace with precise positioning and installation, characterized in that: include: A furnace chamber, wherein an upper flange is arranged on the top of the furnace chamber, and a lower flange is arranged on the bottom of the furnace chamber; A crucible, wherein the crucible is arranged in the furnace chamber; External insulation and lower insulation, the external insulation and the lower insulation form an insulation layer, the insulation layer is arranged on the outside of the crucible, and a movable support rod is fixed to the bottom of the lower insulation; A motion mechanism, the motion mechanism is arranged on the top of the lower flange, the motion mechanism comprises a plane moving component, the plane moving component can drive the movable support rod to drive the thermal insulation layer to move; A closable slide rail is arranged on the top of the furnace cavity and a movable laser locator is provided on the closable slide rail.

2. The induction furnace with precise positioning and installation according to claim 1, characterized in that: The plane moving assembly includes a transverse moving part and a longitudinal moving part; The longitudinal moving part is used to control the longitudinal movement of the movable support rod; the lateral moving part is used to control the lateral movement of the movable support rod.

3. The induction furnace with precise positioning and installation according to claim 1, characterized in that: The motion mechanism further comprises a rotation assembly, and the rotation assembly is used to control the rotation of the movable support rod.

4. The induction furnace with precise positioning and installation according to claim 1, characterized in that: The motion mechanism further comprises a lifting component, and the lifting component is used to control the lifting or lowering of the movable support rod.

5. The induction furnace with precise positioning and installation according to claim 1, characterized in that: The closable slide rail comprises a transverse slide rail and a longitudinal slide rail, and movable laser locators are arranged on the transverse slide rail and the longitudinal slide rail.

6. The induction furnace with precise positioning and installation according to claim 1, characterized in that: A crucible holder is fixed to the bottom of the upper flange. The crucible comprises a transitional crucible cover and a crucible body. The crucible body is fixed to the crucible holder through the transitional crucible cover.

7. The induction furnace with precise positioning and installation according to claim 6, characterized in that: The transitional crucible cover is located between the crucible holder and the crucible body, and is respectively connected to the crucible holder and the crucible body through threads.

8. The induction furnace with precise positioning and installation according to claim 7, characterized in that: The bottom of the crucible holder is provided with an internal thread, the top of the transitional crucible cover is provided with an external thread that matches the internal thread of the bottom of the crucible holder, the bottom of the transitional crucible cover is provided with an internal thread, and the top of the crucible body is provided with an external thread that matches the internal thread of the bottom of the transitional crucible cover.

9. The induction furnace with precise positioning and installation according to claim 7, characterized in that: The bottom of the crucible holder is provided with an external thread, the top of the transitional crucible cover is provided with an internal thread that matches the external thread of the bottom of the crucible holder, the bottom of the transitional crucible cover is provided with an external thread, and the top of the crucible body is provided with an internal thread that matches the external thread of the bottom of the transitional crucible cover.

10. The induction furnace with precise positioning and installation according to claim 1, characterized in that: A graphitized carbon fiber cloth is also arranged between the outer insulation and the crucible. The graphitized carbon fiber cloth comprises a matrix and graphitized carbon fiber bundles arranged in parallel in the matrix. The matrix is ​​tar pitch.

Images