Modularized microwave high-temperature sintering auxiliary heating heat preservation device

Abstract

The invention relates to the technical field of microwave sintering, and discloses a modular microwave high-temperature sintering auxiliary heating heat preservation device which is characterized in that a heat preservation box body is made of a polycrystalline mullite fiber material, and an open temperature measuring hole is formed in the heat preservation box body; the heat insulation body is arranged in the heat preservation box body and is made of a ceramic foam material; the first crucible is arranged in the heat insulation body, and the first crucible is made of a boron nitride material; the second crucible is arranged in the first crucible, a gap is formed between the second crucible and the first crucible, the second crucible is made of a silicon carbide material, and a sintering sample is placed in the second crucible; the silicon carbide powder is filled in a gap between the first crucible and the second crucible; the thermal insulation device has the advantages that the thermal insulation effect is good, the cost is low, the service life is long, the interchangeability is high, the operation is convenient, and the threat to the body health of people is hardly caused.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave sintering, in particular to a modular microwave high-temperature sintering auxiliary heat preservation device. Background Art

[0002] Microwave sintering, a rapid sintering method introduced in the 1970s to the ceramics and alloys industry, is a key feature of microwave sintering, which utilizes the material's absorption of microwave energy to achieve overall heating. Because the material undergoes spontaneous, overall heating, it is heated evenly and with minimal temperature gradients. The resulting material exhibits uniform properties, fine grains, and excellent density. Furthermore, microwave sintering offers high efficiency, energy conservation, environmental protection, and a non-thermal effect, enabling the realization of structures and properties unattainable by traditional sintering methods.

[0003] The common thermal insulation device for microwave sintering of ceramic materials disclosed at present is to fill the mullite fiber box with some other thermal insulation materials, such as:

[0004] An existing Chinese patent discloses a thermal insulation device CN108731475A for microwave sintering of ceramic materials. The thermal insulation device uses a ceramic fiber blanket and a fiberboard alternately stacked to fill a mullite insulation box, and a large amount of mullite fiber is filled in the annular gap between the corundum mullite sleeve and the crucible, resulting in uniform temperature distribution and low cost. However, the fiber blanket and mullite fiber will pulverize after being used several times at high temperature, and the fiberboard may even melt and adhere to the pulverized fiber blanket, resulting in a sharp decline in the thermal insulation effect, and the insulation layer will fail over a large area and need to be frequently replaced. The pulverized insulation material is very easy to dissipate during the replacement process, and the pulverized fibers can enter the alveoli through the nasal cavity and cannot be discharged, causing permanent damage to human health. At the same time, the replacement of the fiber blanket and mullite fiber requires manual cutting and filling, which is cumbersome, time-consuming and labor-intensive, and the fiber dust raised further exacerbates the health risks.

[0005] An existing Chinese patent discloses an auxiliary heat insulation device CN110822899A for microwave sintering. The insulation box is filled entirely with mullite fiber cotton, and a boron nitride crucible and funnel-shaped air guide holes are used for insulation. It can withstand temperatures up to 2000°C and has excellent thermal insulation effects. However, the mullite fiber cotton still has the phenomenon of pulverization or even partial melting after high-temperature recycling, resulting in a sudden decrease in the insulation effect. The crucible collapses with the insulation cotton due to support failure at high temperatures, making it impossible to center the temperature measuring hole and seriously affecting the precise control of the sintering process. In addition, the insulation structure is not modular and the crucible body has a complex shape. The replacement of the insulation cotton requires a lot of manual cutting according to the complex internal structure of the insulation barrel. The operation is complicated and inefficient. A large amount of mullite fiber dust will seriously endanger human health. Summary of the Invention

[0006] The purpose of the present invention is to provide a modular microwave high-temperature sintering auxiliary heat insulation device, which aims to solve or improve at least one of the above-mentioned technical problems, has good insulation effect, low cost, long life, high interchangeability, is easy to operate and poses almost no threat to human health.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a modular microwave high-temperature sintering auxiliary heat preservation device, comprising:

[0008] The heat preservation box is made of polycrystalline mullite fiber material and is provided with an open temperature measuring hole;

[0009] A heat insulator is arranged inside the heat preservation box, and the heat insulator is made of ceramic foam material;

[0010] A first crucible is disposed inside the heat insulator, and the first crucible is made of boron nitride;

[0011] a second crucible, disposed inside the first crucible with a gap between the second crucible and the first crucible, the second crucible being made of silicon carbide and being used to place the sintered sample;

[0012] Silicon carbide powder is filled in the gap between the first crucible and the second crucible;

[0013] The boron nitride air guide tube is used to connect the second crucible with the temperature measuring hole.

[0014] Optionally, the thermal insulation box includes a polycrystalline mullite fiber box with open ends, and a polycrystalline mullite fiber cover plate and a polycrystalline mullite fiber bottom plate detachably connected to the two ends of the polycrystalline mullite fiber box, and the temperature measuring hole is provided on the polycrystalline mullite fiber cover plate.

[0015] Optionally, the thermal insulator includes a second foam ceramic insulator with a groove structure and a first foam ceramic insulator arranged at the open end of the second foam ceramic insulator, and the first foam ceramic insulator is provided with an avoidance hole, and the avoidance hole is used to embed the boron nitride air duct.

[0016] Optionally, the first crucible includes a boron nitride crucible with a groove structure and a boron nitride cover arranged at an open end of the boron nitride crucible, and the boron nitride cover is provided with a communication port for communicating with the boron nitride air duct.

[0017] Optionally, the second crucible includes a silicon carbide crucible with a groove structure and a silicon carbide cover plate, wherein the diameter of the silicon carbide cover plate is smaller than the diameter of the silicon carbide crucible cavity and there is a gap between the silicon carbide cover plate and the boron nitride cover.

[0018] Optionally, first stepped grooves are circumferentially formed at the outer edges of the opposite end surfaces of the polycrystalline mullite fiber cover plate and the polycrystalline mullite fiber bottom plate, and the groove width of the first stepped grooves matches the side wall thickness of the polycrystalline mullite fiber box to achieve positioning and assembly.

[0019] Optionally, a second stepped groove is circumferentially formed on the end surface of the boron nitride cover, and the groove width of the second stepped groove matches the side wall thickness of the boron nitride crucible to achieve positioning and assembly.

[0020] Optionally, the communication port, the boron nitride air guide tube and the temperature measuring hole are coaxially arranged.

[0021] Optionally, the width of the gap between the first crucible and the second crucible is 3-5 mm.

[0022] Optionally, the heat preservation box can withstand a temperature of more than 1700°C, the heat insulator can withstand a temperature of up to 2000°C, and the first crucible can withstand a temperature of up to 2500°C.

[0023] The present invention discloses the following technical effects:

[0024] This device adopts a modular design and uses an integral high-temperature resistant foam ceramic insulation filler between the first crucible and the insulation box. It can withstand a maximum temperature of 2000°C and can be used multiple times for a long time at 1800°C. It has a long life, low cost, and easy operation. The ceramic foam insulation replaces the mullite fiber cotton, which greatly reduces the harm to human health.

[0025] This device adopts a structure in which a first crucible of boron nitride wraps a second crucible of silicon carbide, and silicon carbide powder is filled between the first crucible and the second crucible. Boron nitride has the characteristics of low thermal expansion and high-temperature stability, and its stable operating temperature can reach above 2000°C. The second crucible of silicon carbide and silicon carbide powder have good wave absorption properties, which can help increase the sintering temperature. This auxiliary heat and heat preservation device ensures stable and rapid temperature rise of the material during the sintering process.

[0026] All structures of this device adopt modular design ideas, which are very convenient to disassemble and easy to replace when local components are damaged, and have high interchangeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2Schematic diagram of the heat insulation structure of the present invention.

[0030] In the figure: 1. Temperature measuring hole; 2. Polycrystalline mullite fiber cover; 3. Polycrystalline mullite fiber box; 4. First foam ceramic insulator; 5. Second foam ceramic insulator; 6. Boron nitride air duct; 7. Boron nitride cover; 8. Boron nitride crucible; 9. Silicon carbide powder; 10. Silicon carbide crucible; 11. Polycrystalline mullite fiber bottom plate; 12. Silicon carbide cover; 13. Sintered 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] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Reference Figure 1-Figure 2 The present invention provides a modular microwave high-temperature sintering auxiliary heat preservation device, comprising:

[0034] The heat preservation box is made of polycrystalline mullite fiber material, and an open temperature measuring hole 1 is provided on the heat preservation box;

[0035] The heat insulator is arranged inside the heat preservation box and is made of ceramic foam material;

[0036] A first crucible is disposed inside the heat insulator, and the first crucible is made of boron nitride, preferably hexagonal boron nitride;

[0037] A second crucible is disposed inside the first crucible with a gap between the second crucible and the first crucible. The second crucible is made of silicon carbide and is used to place the sintered sample 13.

[0038] Silicon carbide powder 9 is filled in the gap between the first crucible and the second crucible;

[0039] The boron nitride gas guide tube 6 is used to connect the second crucible with the temperature measuring hole 1 .

[0040] In one embodiment of the present invention, the thermal insulation housing includes a polycrystalline mullite fiber housing 3 with open ends, and a polycrystalline mullite fiber cover plate 2 and a polycrystalline mullite fiber base plate 11 detachably connected to the ends of the polycrystalline mullite fiber housing 3. The polycrystalline mullite fiber cover plate 2 is provided with a temperature measurement hole. A first stepped groove is circumferentially defined at the outer edges of the opposing end surfaces of the polycrystalline mullite fiber cover plate 2 and the polycrystalline mullite fiber base plate 11. The groove width of the first stepped groove matches the sidewall thickness of the polycrystalline mullite fiber housing 3 to facilitate positioning and assembly.

[0041] The first stepped grooves on the polycrystalline mullite fiber cover plate 2 and the polycrystalline mullite fiber bottom plate 11 enable the polycrystalline mullite fiber cover plate 2 and the polycrystalline mullite fiber bottom plate 11 to be quickly assembled and disassembled with the polycrystalline mullite fiber box 3, thereby improving usage efficiency.

[0042] In one embodiment of the present invention, the insulator includes a second foam ceramic insulator 5 with a groove structure and a first foam ceramic insulator 4 arranged at the open end of the second foam ceramic insulator 5. The first foam ceramic insulator 4 is provided with an avoidance hole for embedding the boron nitride air guide tube 6.

[0043] The first foam ceramic insulator 4 and the second foam ceramic insulator 5 are both composed of two semi-cylinders cut along the axis to reduce thermal stress during sintering.

[0044] In one embodiment of the present invention, the first crucible includes a boron nitride crucible 8 with a groove structure and a boron nitride lid 7 disposed at the open end of the boron nitride crucible 8. The boron nitride lid 7 has a communication port for communicating with the boron nitride air duct 6. A second stepped groove is circumferentially defined on the end surface of the boron nitride lid 7. The width of the second stepped groove matches the sidewall thickness of the boron nitride crucible 8 to facilitate positioning and assembly.

[0045] The second stepped groove on the boron nitride cover 7 facilitates assembly with the boron nitride crucible 8. When in use, only the first foam ceramic insulation 4, the polycrystalline mullite fiber cover 2 and the boron nitride cover 7 above the first crucible need to be removed to remove the sintered sample, which is convenient to operate and efficient.

[0046] The diameter of the hole of the communication port is 30-35 mm.

[0047] In one embodiment of the present invention, the second crucible includes a silicon carbide crucible 10 with a groove structure and a silicon carbide cover plate 12. The diameter of the silicon carbide cover plate 12 is smaller than the diameter of the cavity of the silicon carbide crucible 10 and there is a gap between the silicon carbide cover plate 12 and the boron nitride lid 7.

[0048] The height of the silicon carbide crucible 10 is 2 mm smaller than the inner height of the boron nitride crucible 8 , so that after the boron nitride lid 7 and the boron nitride crucible 8 are buckled together, the boron nitride lid 7 and the silicon carbide crucible 10 are abutted against each other.

[0049] In one embodiment of the present invention, the communication port, the boron nitride air guide tube 6 and the temperature measuring hole 1 are coaxially arranged.

[0050] It integrates the triple effects of temperature measurement, exhaust and heat insulation, effectively ensuring the heat preservation effect and long service life of the insulation box.

[0051] In one embodiment of the present invention, the width of the gap between the first crucible and the second crucible is 3-5 mm, and the height of the silicon nitride powder 9 is the same as that of the silicon carbide crucible 10 , that is, the silicon carbide powder 9 fills the gap.

[0052] In one embodiment of the present invention, the heat preservation box can withstand a temperature of more than 1700°C, the heat insulator can withstand a temperature of up to 2000°C, and the first crucible can withstand a temperature of up to 2500°C.

[0053] The materials selected for the microwave high-temperature sintering auxiliary heat insulation device of the present invention have the characteristics of good wave transmittance, low thermal conductivity, low thermal expansion coefficient and high temperature resistance in all temperature ranges. The device adopts a modular design and is easy to operate, solving the problems of existing insulation devices such as complex structure, poor insulation effect, short service life, inconvenient manufacturing and operation, and permanent damage to human health.

[0054] This device allows for rapid access to sintered samples without the need for additional operations such as powder filling, resulting in high efficiency. Furthermore, this device offers high reliability and stability, enabling long-term, stable, and multiple-use performance at 1800°C, meeting requirements for rapid heating and cooling rates exceeding 50°C / min.

[0055] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0056] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A modular microwave high-temperature sintering auxiliary heat preservation device, characterized in that: include: The heat-insulating box is made of a polycrystalline mullite fiber material, and an open temperature measuring hole (1) is provided on the heat-insulating box; A heat insulator is arranged inside the heat preservation box, and the heat insulator is made of ceramic foam material; A first crucible is disposed inside the heat insulator, and the first crucible is made of boron nitride; a second crucible, arranged inside the first crucible and having a gap between the first crucible and the second crucible, the second crucible being made of silicon carbide and being used to place a sintered sample (13); Silicon carbide powder (9) is filled in the gap between the first crucible and the second crucible; The boron nitride air guide tube (6) is used to connect the second crucible with the temperature measuring hole (1).

2. A modular microwave high-temperature sintering auxiliary heat preservation device according to claim 1, characterized in that: The heat-insulating box comprises a polycrystalline mullite fiber box (3) with two open ends, and a polycrystalline mullite fiber cover plate (2) and a polycrystalline mullite fiber bottom plate (11) detachably connected to the two ends of the polycrystalline mullite fiber box (3), respectively. The temperature measuring hole is provided on the polycrystalline mullite fiber cover plate (2).

3. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 1, characterized in that: The thermal insulator comprises a second foam ceramic thermal insulator (5) having a groove structure and a first foam ceramic thermal insulator (4) arranged at the open end of the second foam ceramic thermal insulator (5); the first foam ceramic thermal insulator (4) is provided with an avoidance hole, and the avoidance hole is used to embed the boron nitride air guide tube (6).

4. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 1, characterized in that: The first crucible comprises a boron nitride crucible (8) with a groove structure and a boron nitride cover (7) arranged at the open end of the boron nitride crucible (8); the boron nitride cover (7) is provided with a communication port for communicating with the boron nitride air guide tube (6).

5. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 4, characterized in that: The second crucible comprises a silicon carbide crucible (10) with a groove structure and a silicon carbide cover plate (12). The diameter of the silicon carbide cover plate (12) is smaller than the diameter of the cavity of the silicon carbide crucible (10), and there is a gap between the silicon carbide cover plate (12) and the boron nitride cover (7).

6. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 2, characterized in that: First stepped grooves are respectively provided circumferentially at the outer edges of the opposite end faces of the polycrystalline mullite fiber cover plate (2) and the polycrystalline mullite fiber base plate (11); the groove width of the first stepped grooves matches the side wall thickness of the polycrystalline mullite fiber box body (3) to achieve positioning and assembly.

7. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 4, characterized in that: A second stepped groove is provided in the circumferential direction of the end surface of the boron nitride cover (7), and the groove width of the second stepped groove matches the side wall thickness of the boron nitride crucible (8) to achieve positioning and assembly.

8. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 4, characterized in that: The communication port, the boron nitride air guide tube (6) and the temperature measuring hole (1) are coaxially arranged.

9. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 1, characterized in that: The width of the gap between the first crucible and the second crucible is 3-5 mm.

10. The modular microwave high-temperature sintering auxiliary heat preservation device according to claim 1, characterized in that: The heat preservation box can withstand a temperature of more than 1700°C, the heat insulator can withstand a temperature of up to 2000°C, and the first crucible can withstand a temperature of up to 2500°C.

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