A new sintered tungsten clamp crucible

Abstract

This utility model discloses a novel sintering tungsten ...

Description

Technical Field

[0001] This utility model relates to the field of sintering crucible technology, specifically a novel sintering tungsten crucible. Background Technology

[0002] A sintering crucible is a crucible manufactured through a sintering process. Sintering is a process in which powder materials are heated to a certain degree at a high temperature, causing the particles to bond together and form a solid structure. During sintering, the material is not completely melted, but rather the powder particles are allowed to bond together to form a dense whole.

[0003] For a long time, the growth of high-quality colored corundum gemstones has been carried out using the iridium crucible Czochralski method. In recent years, the price of iridium has remained high, and the processing cost of crucibles is high. The amount of volatilization during use is large, and the recovery rate of volatilized substances is low, making the gemstone production cost extremely high. Developing and using tungsten crucible gemstone growth technology can effectively reduce the initial investment cost and production cost of gemstone production. However, the main technical difficulties in the use of tungsten crucibles are: first, the impact of tungsten crucible volatilization on product quality; and second, the problem of temperature gradient and liquid flow turbulence in the melt inside the sintered tungsten crucible under the action of an electromagnetic field, which makes it difficult to form a temperature field suitable for gemstone growth. Therefore, improvements are needed. Utility Model Content

[0004] The purpose of this invention is to provide a novel sintering tungsten crucible to solve the problems of easy volatilization and turbulent temperature gradient and liquid flow of the melt in the crucible mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a novel sintering tungsten tungsten tampere, comprising a heating furnace body, a crucible support frame inside the heating furnace body, a crucible body on the crucible support frame, the top of the inner wall of the crucible body having an inclined structure with an inclination angle of 2-5°, the bottom side of the crucible body having an arc-shaped structure, a front heater on the outer side of the crucible body, a crystal inside the crucible body, and a rear heater on the outer side of the crystal.

[0006] Preferably, the crucible support frame has a groove on the top, which corresponds to the horizontal position of the bottom of the crucible body.

[0007] Preferably, the crucible body contains a solution, and the solution contains crystals.

[0008] Preferably, the front heater and the rear heater are fixed to the inner wall of the heating furnace, and both the front heater and the rear heater are medium-frequency heating coils.

[0009] Preferably, the inner wall of the heating furnace is provided with a modular heat insulation cover, the lower diameter of which is larger than the upper diameter.

[0010] Preferably, the top of the heating furnace body is provided with an exhaust port to efficiently discharge volatiles by utilizing the rising effect of hot air.

[0011] Preferably, an observation and maintenance port is provided on one side of the heating furnace body. The observation and maintenance port has an inclined structure, and the lower end of the observation and maintenance port is larger than the upper end.

[0012] Compared with the prior art, the beneficial effects of this utility model are: (1) This device innovates the sintering technology of the crucible body, the shape of the crucible body and the thermal field design of the crucible body, so as to grow high-quality red, blue and green colored gemstones. The application of this patented technology to grow corundum colored gemstones solves the problem of using expensive precious metal iridium, greatly saves equipment investment and reduces production costs by 75-85%.

[0013] (2) This device achieves the purpose of increasing the radial and axial temperature gradient of the liquid surface and melt by setting the top of the inner wall of the crucible body to an inclined structure, and also controls the difference between the upper and lower ends of the crystal diameter equal part within 2 mm. By making the bottom side of the crucible body into an arc shape, the temperature gradient near the solid-liquid interface can be significantly improved, which helps to avoid problems such as crystal growth ridge widening and component undercooling. Secondly, the bottom shape of the crucible body affects the strength of natural convection of the melt. When using a crucible body with an arc bottom, the axial and radial temperature gradient in the melt is larger, that is, the driving force of natural convection is greater, and the natural convection in the melt is stronger, which is beneficial to the growth of doped crystals.

[0014] (3) This device sets a front heater and a rear heater on the outside of the crucible body and the top of the crucible body respectively. The front heater and the rear heater have different diameters, which can heat the crystal and the crucible body according to their size. At the same time, the front heater and the rear heater use medium frequency heating coils with a relatively low diameter-to-height ratio, which can improve the thermal uniformity of the crucible body wall and improve the crystal growth quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the connection structure between the main body of a novel sintering tungsten tungsten tamper crucible and the heating furnace body according to this utility model; Figure 2 This is a cross-sectional view of the crucible body of a novel sintering tungsten tungsten tamper according to this utility model; Figure 3 This is a top view of a crucible support frame for a novel sintering tungsten tungsten tamper crucible according to this utility model.

[0016] In the diagram: 1. Heating furnace body; 2. Rear heater; 3. Crystal; 4. Front heater; 5. Crucible support frame; 6. Melt; 7. Modular insulation cover; 8. Crucible body. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Please see Figure 1-3This utility model provides a technical solution: a novel sintering tungsten tungsten tamper, comprising a heating furnace body 1, an inspection door at the end of the heating furnace body 1 for easy addition of crystals 3, a crucible support frame 5 inside the heating furnace body 1, and a modular heat insulation cover 7 on the inner wall of the heating furnace body 1. The lower diameter of the modular heat insulation cover 7 is larger than the upper diameter of the modular heat insulation cover 7. This structural design of the modular heat insulation cover 7 avoids uneven thermal field caused by cracking of the zirconium oxide insulation material. An exhaust port is provided at the top of the heating furnace body 1 to efficiently discharge volatiles using the rising effect of hot air. This structure ensures normal exhaust. An observation and maintenance port is provided on one side of the heating furnace body 1. The observation and maintenance port has an inclined structure for observation and maintenance. The lower end of the crucible support frame 5 is larger than the upper end, facilitating inspection and observation. A groove is provided at the top of the crucible support frame 5, corresponding to the horizontal position of the bottom of the crucible body 8. This structure creates a suspended structure between the crucible support frame 5 and the bottom of the crucible body 8, ensuring a positive temperature gradient within the melt 6. The sintered crucible body 8 has a thick bottom and high heat capacity. In the induction heating field, the center temperature of the crucible body 8's bottom is too low. This crucible support frame 5 significantly increases the temperature of the center by reducing heat conduction. Due to the large thickness and high strength of the sintered crucible body 8, deformation of the crucible body 8's bottom is prevented, ensuring the stability of the temperature field. The crucible body 8 is mounted on the crucible support frame 5. After the main body 8 is placed on the crucible support frame 5, the crucible support frame 5 is installed from the bottom of the heating furnace body 1. The bottom of the heating furnace body 1 can be opened for easy maintenance. The crucible main body 8 contains a melt 6, and the melt 6 contains crystals 3. The top of the inner wall of the crucible main body 8 is inclined, which increases the radial and axial temperature gradient between the liquid surface and the melt 6, and also controls the difference between the upper and lower diameters of the crystals 3 within 2mm. The increase in thickness of the bottom of the crucible main body 8 compared to the upper wall is controlled within 1mm, achieving a stable temperature gradient with an inclination angle of 2-5° throughout the production process. The bottom side of the crucible main body 8 has a rounded structure, designed with a flat bottom and rounded corners. With an arc radius of R10-R20, the growth interface remains a slightly convex arc. No small facets form at the bottom of crystal 3, and no cellular structures appear at the bottom interface. The quality of crystal 3 is consistent throughout, and the single-furnace crystallization rate exceeds 80%. During the growth of crystal 3, the axial temperature gradient near the solid-liquid interface and the axial temperature gradient within crystal 3 gradually decrease, increasing the difficulty of crystallization, especially for doped gemstone crystal 3. It is prone to defects such as component undercooling and cloud formation, which seriously affect the quality of crystal 3. Experiments have shown that the bottom arc-angle crucible body 8 can significantly improve the temperature gradient near the solid-liquid interface, which helps to avoid problems such as ridge widening and component undercooling in crystal 3.Secondly, the shape of the crucible body 8's bottom affects the strength of the natural convection of the melt. When using a crucible body 8 with a bottom arc angle, the axial and radial temperature gradients in the melt 6 are larger, meaning the driving force for natural convection is greater, and the natural convection within the melt 6 is stronger, which is beneficial to the growth of the doped crystal 3. A front heater 4 is provided on the outside of the crucible body 8. The front heater 4 and the rear heater 2 are fixed to the inner wall of the heating furnace body 1. Both the front heater 4 and the rear heater 2 are medium-frequency heating coils. In this structure, the front heater 4 and the rear heater 2 are selected with appropriate medium-frequency frequencies to adapt to the characteristics of the large thickness and large heat capacity of the crucible body 8. Importantly, this reduces the volatilization of the crucible body 8 under medium-frequency action. The rear heater 2 is set to adapt to the different requirements of different colored gemstone varieties for the thermal field environment. The crucible body 8 is equipped with... Crystal 3, with a post-heater 2 on its outer side. The crucible body 8 is sintered with tungsten powder and other impurity elements in appropriate amounts. The particle size of the tungsten powder is a direct factor affecting the sintering density of the tungsten crucible. For example: ideal particle size: tungsten powder particles need to meet the typical value of 0.5–2 μm, ranging from submicron to several micrometers. The specific selection needs to be combined with the sintering process: coarse particles 1–5 μm: suitable for conventional pressing sintering (CIP) + high-temperature sintering, achieving densification through particle rearrangement; ultrafine particles <1 μm: require discharge plasma sintering (SPS) or hot isostatic pressing (HIP), utilizing a rapid diffusion mechanism to achieve a near-theoretical density >99%; particle distribution: a narrow particle size distribution, such as a unimodal distribution, can reduce porosity and improve densification uniformity. Impurity elements can be: Y₂O₃ 0.2–1.0. Refining grain size, enhancing grain boundary bonding, and reducing the high-temperature volatilization rate inhibits the diffusion of tungsten atoms along grain boundaries. Volatilization suppression: Y₂O₃ doping can reduce the volatilization rate of tungsten at 2000°C by 30–50%. The tungsten powder particles described above are examples and are not limited to the data mentioned.

[0019] Working principle: When using this new type of sintering tungsten tungsten tamper, the melt 6 is first added to the inside of the crucible body 8, and then the crystal 3 is fixed inside the melt 6. Then, the front heater 4 and the rear heater 2 are turned on to heat the crystal 3 and the crucible body 8, so that the crystal 3 grows with high quality in a uniform thermal field environment, thereby improving the growth quality of the crystal 3 and saving production costs.

[0020] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel sintering tungsten tungsten tongs, comprising a heating furnace body (1), characterized in that: The heating furnace body (1) is provided with a crucible support frame (5) inside, and a crucible body (8) is provided on the crucible support frame (5). The top of the inner wall of the crucible body (8) is inclined with an inclination angle of 2-5°. The bottom side of the crucible body (8) is arc-shaped. A front heater (4) is provided on the outside of the crucible body (8). A crystal (3) is provided inside the crucible body (8). A rear heater (2) is provided on the outside of the crystal (3).

2. The novel sintering tungsten clamping crucible according to claim 1, characterized in that: The crucible support frame (5) has a groove on its top, which corresponds to the bottom horizontal position of the crucible body (8).

3. The novel sintering tungsten clamping crucible according to claim 1, characterized in that: The crucible body (8) contains a solution (6), and the solution (6) contains crystals (3).

4. The novel sintering tungsten clamping crucible according to claim 1, characterized in that: The front heater (4) and the rear heater (2) are fixed on the inner wall of the heating furnace body (1), and both the front heater (4) and the rear heater (2) are medium frequency heating coils.

5. A novel sintering tungsten clamping crucible according to claim 1, characterized in that: The inner wall of the heating furnace body (1) is provided with a modular heat preservation cover (7), and the lower diameter of the modular heat preservation cover (7) is larger than the upper diameter of the modular heat preservation cover (7).

6. A novel sintering tungsten clamping crucible according to claim 1, characterized in that: The top of the heating furnace body (1) is provided with an exhaust hole, which utilizes the rising effect of hot air to efficiently discharge volatiles.

7. A novel sintering tungsten clamping crucible according to claim 1, characterized in that: The heating furnace body (1) has an observation and maintenance port on one side. The observation and maintenance port has an inclined structure and the lower end of the observation and maintenance port is larger than the upper end.

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