A multi-layer composite thermal field structure of a sapphire single crystal furnace

Abstract

The utility model relates to a kind of multilayer composite thermal field structure of sapphire single crystal furnace, it relates to sapphire crystal growth equipment technical field.The utility model solves the problem that existing thermal field structure is mostly single material, there is low thermal efficiency, material short life and unstable temperature gradient.The utility model includes three heat insulation layers by inside to outside sequentially nested arrangement, the three heat insulation layers are sequentially by inside to outside molybdenum heat insulation layer, high-temperature ceramic heat insulation layer and graphite carbon felt heat insulation layer, the expansion buffer gap with consistent thickness is formed between each adjacent two heat insulation layers by multiple interlayer support members arranged uniformly, three heat insulation layers are fixed by multiple heat insulation layer connecting pieces arranged uniformly, heat insulation layer connecting piece is high-temperature resistant ceramic bolt, multiple high-temperature resistant ceramic bolts are equidistant array distribution along the circumferential direction and axial direction of thermal field structure, and interlayer support member is ceramic gasket.The utility model is used to improve heat insulation efficiency, reduce energy consumption and prolong equipment life by the synergistic effect of multilayer material.

Description

Technical Field

[0001] This utility model relates to the technical field of sapphire crystal growth equipment, specifically to a multi-layer composite thermal field structure for a sapphire single crystal furnace. Background Technology

[0002] A sapphire single crystal furnace is a high-end crystal growth device used for the artificial growth of sapphire single crystals (α-alumina, Al2O3). During crystal growth, the sapphire single crystal furnace needs to maintain a high temperature (>2200℃) and a uniform temperature field. The thermal field structure is key to controlling the thermal field distribution within the furnace. By reflecting the thermal radiation from the heating element, the furnace achieves the required temperature for crystal growth and forms a stable temperature field and temperature gradient.

[0003] Traditional thermal field structures often use a single material (such as tungsten or molybdenum), which presents the following problems:

[0004] Firstly, it has low thermal efficiency: a single material cannot simultaneously achieve both heat reflection and heat barrier properties, resulting in significant heat loss and high energy consumption.

[0005] Secondly, the material lifespan is short: Under high temperature conditions, single tungsten-molybdenum materials are prone to problems such as material volatilization, deformation, surface adhesion or ablation, resulting in a short lifespan of the thermal field components and the need for frequent replacement of the thermal field components.

[0006] Third, the temperature gradient is unstable: the single material structure has insufficient thermal buffering capacity, and the heat reflection is uneven after the molybdenum component is deformed at high temperature, which leads to the instability of the temperature field inside the furnace and affects the crystal growth quality.

[0007] Therefore, a composite material thermal field structure for sapphire single crystal furnace is needed to solve the aforementioned problems of single-material thermal field structures. Utility Model Content

[0008] The purpose of this invention is to address the problems of low thermal efficiency, short material life, and unstable temperature gradient in existing thermal field structures, which mostly use a single material. Therefore, this invention provides a multi-layer composite thermal field structure for a sapphire single crystal furnace.

[0009] The technical solution of this utility model is:

[0010] A multi-layer composite thermal field structure for a sapphire single crystal furnace includes three heat insulation layers arranged nested from the inside out. The three heat insulation layers are, from the inside out, a molybdenum heat insulation layer 1, a high-temperature ceramic heat insulation layer 2, and a graphite carbon felt heat insulation layer 3. An expansion buffer gap 5 of uniform thickness is formed between each two adjacent heat insulation layers by a plurality of uniformly arranged interlayer supports 4. The three heat insulation layers are fixed by a plurality of uniformly arranged heat insulation layer connectors 6.

[0011] Furthermore, the molybdenum heat insulation layer 1 is a polished molybdenum plate with a purity of ≥99.95% and a thickness of 0.3mm~2mm.

[0012] Furthermore, the high-temperature ceramic insulation layer 2 is a porous zirconia ceramic or a porous alumina ceramic, the porosity of the high-temperature ceramic insulation layer 2 is 40%~60%, and the thickness of the high-temperature ceramic insulation layer 2 is 15mm~75mm.

[0013] Furthermore, the graphite carbon felt insulation layer 3 is a flexible graphite carbon felt, with a density of 0.1 g / cm³ to 0.3 g / cm³ and a thickness of 10 mm to 20 mm.

[0014] Furthermore, the heat insulation layer connector 6 is a high-temperature resistant ceramic bolt, which is made of zirconium oxide or silicon nitride and has a diameter of 5mm to 10mm.

[0015] Furthermore, multiple high-temperature resistant ceramic bolts are distributed in an equidistant array along the circumferential and axial directions of the thermal field structure.

[0016] Furthermore, the interlayer support 4 is a ceramic washer that matches the high-temperature resistant ceramic bolt, and the thickness of the ceramic washer is 0.5mm~2.5mm.

[0017] Furthermore, each insulation layer edge is edged with molybdenum alloy, with an edge width of 3mm to 5mm.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The multi-layer composite thermal field structure of this utility model has a good energy-saving effect. Through the synergistic effect of multiple materials, the combined heat reflection and heat barrier effects can improve the thermal efficiency of the furnace cavity by more than 30%.

[0020] 2. The multi-layer composite thermal field structure of this utility model can effectively increase the service life of the equipment. The outer layer of graphite carbon felt and the middle layer of high-temperature ceramic are stable and not prone to high-temperature volatilization and deformation, and protect the inner layer of molybdenum plate, thus extending the overall service life of the thermal field structure by 2 to 3 times.

[0021] 3. The multi-layer composite thermal field structure of this utility model can ensure excellent crystal quality, uniform and stable thermal field temperature gradient, and reduced crystal dislocation density. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the multi-layer composite thermal field structure of a sapphire single crystal furnace according to this utility model.

[0023] In the diagram: 1. Molybdenum insulation layer; 2. High-temperature ceramic insulation layer; 3. Graphite carbon felt insulation layer; 4. Interlayer support; 5. Expansion buffer gap; 6. Insulation layer connector. Detailed Implementation

[0024] Specific implementation method one: Combining Figure 1 This embodiment describes a multi-layer composite thermal field structure for a sapphire single crystal furnace. It includes three heat insulation layers arranged nested from the inside out. The three heat insulation layers are, from the inside out, a molybdenum heat insulation layer 1, a high-temperature ceramic heat insulation layer 2, and a graphite carbon felt heat insulation layer 3. An expansion buffer gap 5 of uniform thickness is formed between each pair of adjacent heat insulation layers by a plurality of uniformly arranged interlayer supports 4. The three heat insulation layers are fixed by a plurality of uniformly arranged heat insulation layer connectors 6.

[0025] In this embodiment, the thermal field structure improves thermal insulation efficiency, reduces equipment operating energy consumption, and extends the service life of the thermal field through the synergistic effect of multiple materials. It fully combines the properties of molybdenum, high-temperature ceramics, and graphite carbon felt to achieve highly efficient thermal insulation and extend the service life of the thermal field.

[0026] Specific Implementation Method Two: Combining Figure 1 In this embodiment, the molybdenum insulation layer 1 is a polished molybdenum plate with a purity ≥99.95% and a thickness of 0.3mm~2mm. This configuration, with the surface of the high-purity molybdenum plate polished, utilizes the high reflectivity of molybdenum (>85%) to reflect thermal radiation back into the furnace cavity. Other components and connections are the same as in Specific Embodiment 1.

[0027] Specific implementation method three: Combining Figure 1 In this embodiment, the high-temperature ceramic insulation layer 2 is made of porous zirconia (ZrO2) ceramic or porous alumina (Al2O3) ceramic. The porosity of the high-temperature ceramic insulation layer 2 is 40%~60%, and the thickness is 15mm~75mm. This configuration combines low thermal conductivity (<1.5W / m·K) and high-temperature stability (temperature resistance >2000℃), blocking heat conduction and reducing heat loss. Other components and connections are the same as in specific embodiments one or two.

[0028] Specific implementation method four: Combination Figure 1 In this embodiment, the graphite carbon felt insulation layer 3 is a flexible graphite carbon felt with a density of 0.1 g / cm³ to 0.3 g / cm³ and a thickness of 10 mm to 20 mm. This configuration utilizes its low thermal conductivity (<0.1 W / m·K) and thermal shock resistance to absorb residual heat and buffer external mechanical vibrations, protecting the inner structure. Other components and connections are the same as in specific embodiments one, two, or three.

[0029] Specific Implementation Method Five: Combining Figure 1 In this embodiment, the heat insulation layer connector 6 is a high-temperature resistant ceramic bolt. The high-temperature resistant ceramic bolt is made of zirconium oxide or silicon nitride, and its diameter is 5mm~10mm. With this configuration, the three-layer structure is fixed by the high-temperature resistant ceramic bolt. Using zirconium oxide (ZrO2) ceramic or silicon nitride (Si3N4) ceramic, it has a temperature resistance >2000℃, excellent thermal shock resistance, can withstand rapid heating and cooling, and has a low coefficient of thermal expansion, similar to that of the molybdenum heat insulation layer 1, thus reducing thermal stress. Other components and connection relationships are the same as in specific embodiments one, two, three, or four.

[0030] Specific Implementation Method Six: Combination Figure 1 This embodiment describes a configuration in which multiple high-temperature resistant ceramic bolts are distributed in an equidistant array along the circumferential and axial directions of the thermal field structure. This arrangement, by using multiple high-temperature resistant ceramic bolts arranged in an equidistant array along the circumferential and axial directions within the thermal field structure, not only connects the insulation layer but also ensures that the ceramic gaskets installed on each high-temperature resistant ceramic bolt are evenly distributed between the insulation layers, thereby ensuring a consistent expansion buffer gap 5. Other components and connection relationships are the same as in specific embodiments one, two, three, four, or five.

[0031] In this embodiment, the heat insulation layer consists of a molybdenum heat insulation layer 1, a high-temperature ceramic heat insulation layer 2, and a graphite carbon felt heat insulation layer 3.

[0032] Specific implementation method seven: Combination Figure 1 In this embodiment, the interlayer support 4 is a ceramic washer that matches the high-temperature resistant ceramic bolts, and the thickness of the ceramic washer is 0.5mm to 2.5mm. With this configuration, the three-layer structure is fixed together by the high-temperature resistant ceramic bolts, and the layers are spaced apart by the ceramic washer that matches the bolts, leaving a gap of 0.5mm to 2.5mm between the layers. The gap is adjusted by the interlayer support 4 that matches the high-temperature ceramic bolts, which can prevent stress concentration due to thermal expansion. Other components and connections are the same as in specific embodiments one, two, three, four, five, or six.

[0033] Specific implementation method eight: Combination Figure 1 In this embodiment, each edge of the insulation layer is edged with molybdenum alloy, with an edge width of 3mm to 5mm. This arrangement, with the edges of the insulation layers edged with molybdenum alloy, enhances the overall rigidity of the structure. Other components and connections are the same as in specific embodiments one, two, three, four, five, six, or seven.

[0034] Working principle

[0035] Combination Figure 1This invention describes the working principle of a multi-layer composite thermal field structure for a sapphire single crystal furnace: High-temperature ceramic bolts are evenly distributed in an array along the circumference and axial direction of the thermal field structure. Through holes are drilled at corresponding positions of the molybdenum insulation layer 1, the high-temperature ceramic insulation layer 2, and the graphite carbon felt insulation layer 3. The edges of the holes are chamfered to prevent the ceramic layers from cracking. The three layers are temporarily fixed by locating pins to ensure that the through-hole axes coincide. High-temperature ceramic bolts are inserted from the outermost layer to the innermost layer, with ceramic washers added sequentially between layers. Nuts are then tightened evenly using a torque wrench. A gap of 0.5mm to 2.5mm is reserved between the insulation layers to avoid stress concentration due to thermal expansion. The edges of the insulation layers are edged with molybdenum alloy with a width of 3mm to 5mm to enhance the overall rigidity of the thermal field structure. Through the synergistic effect of the multiple materials, the thermal field insulation efficiency can be improved, the energy consumption of equipment operation can be reduced, and the service life of the thermal field can be extended.

[0036] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A multi-layered composite thermal field structure of a sapphire single crystal furnace, characterized by: It includes three heat insulation layers arranged in a nested manner from the inside out. The three heat insulation layers are, from the inside out, a molybdenum heat insulation layer (1), a high-temperature ceramic heat insulation layer (2), and a graphite carbon felt heat insulation layer (3). An expansion buffer gap (5) of uniform thickness is formed between each two adjacent heat insulation layers by a plurality of uniformly arranged interlayer supports (4). The three heat insulation layers are fixed by a plurality of uniformly arranged heat insulation layer connectors (6).

2. The multilayer composite thermal field structure of a sapphire single crystal furnace according to claim 1, characterized in that: The molybdenum heat insulation layer (1) is a polished molybdenum plate with a purity of ≥99.95% and a thickness of 0.3mm~2mm.

3. The multilayer composite thermal field structure of a sapphire single crystal furnace according to claim 2, characterized in that: The high-temperature ceramic insulation layer (2) is a porous zirconia ceramic or a porous alumina ceramic. The porosity of the high-temperature ceramic insulation layer (2) is 40%~60%, and the thickness of the high-temperature ceramic insulation layer (2) is 15mm~75mm.

4. The multilayer composite thermal field structure of a sapphire single crystal furnace according to claim 3, characterized in that: The graphite carbon felt insulation layer (3) is a flexible graphite carbon felt with a density of 0.1g / cm³~0.3g / cm³ and a thickness of 10mm~20mm.

5. A multi-layer composite thermal field structure for a sapphire single crystal furnace according to claim 1 or 4, characterized in that: The heat insulation layer connector (6) is a high-temperature resistant ceramic bolt, which is made of zirconium oxide or silicon nitride and has a diameter of 5mm to 10mm.

6. The multilayer composite thermal field structure of a sapphire single crystal furnace according to claim 5, characterized in that: Multiple high-temperature resistant ceramic bolts are distributed in an equidistant array along the circumferential and axial directions of the thermal field structure.

7. The multilayer composite thermal field structure of a sapphire single crystal furnace according to claim 6, characterized in that: The interlayer support (4) is a ceramic gasket that is matched with the high-temperature resistant ceramic bolt. The thickness of the ceramic gasket is 0.5mm~2.5mm.

8. A multilayer composite thermal field structure for a sapphire single crystal furnace according to claim 1, 2, 3 or 4, characterized in that: Each insulation layer is edged with molybdenum alloy, with an edge width of 3mm to 5mm.

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