Vacuum pipeline with thermal barrier coating applied at high temperature

Abstract

The utility model discloses a vacuum pipeline with a thermal barrier coating applied at high temperature, the vacuum pipeline is used for connecting the bottom of a single crystal furnace and a negative pressure device, the thermal barrier coating is sprayed on the inner wall of the vacuum pipeline, the vacuum pipeline comprises a plurality of vacuum pipes, the vacuum pipes comprise a first pipeline and a second pipeline, the second pipeline is connected to the side face of the first pipeline, the second pipeline is connected with the negative pressure device through a pipeline, the two ends of the first pipeline are open, and the lower end of the first pipeline is sealed through a sealing head. Meanwhile, the thermal barrier coating can isolate heat of leaked molten silicon, and the potential safety hazard of molten silicon leakage is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal furnaces, and specifically relates to a vacuum pipeline with a thermal barrier coating for high-temperature applications. Background Technique

[0002] In many Cz single crystal growth furnaces, in order to meet the needs of crystal growth, the single crystal furnace needs to be evacuated, so the vacuum pipeline is directly connected to the furnace bottom plate. When the single crystal furnace manufactures single crystal silicon, the highest temperature can reach 1600 °C. In order to withstand this temperature, the vacuum pipeline generally uses stainless steel material. However, stainless steel has good thermal conductivity and is easy to scald operators. Therefore, a cooling water path is introduced outside it to reduce the temperature of the vacuum pipeline. This cooling method has a fast heat transfer efficiency but high energy consumption;

[0003] Moreover, after the single crystal furnace is used for a long time, the problem of thermal failure will occur, resulting in a risk of molten silicon leakage. When the molten silicon leaks into the vacuum pipeline, the high temperature will cause the stainless steel to melt, which has a high safety hazard. Therefore, the vacuum pipeline with a thermal barrier coating for high-temperature applications is designed to improve the energy utilization rate and reduce the safety hazard when molten silicon leaks. Content of the Utility Model

[0004] The purpose of the utility model is to provide a vacuum pipeline with a thermal barrier coating for high-temperature applications. By spraying a thermal barrier coating on the inner wall of the vacuum pipeline, the heat of the leaked molten silicon is isolated by the thermal barrier coating, so that the molten silicon is only 1250 °C when it is transferred to the pipeline surface, reducing the safety hazard of molten silicon leakage. At the same time, the thermal barrier coating can reduce the heat loss caused by the cooling water path and reduce the energy loss, having an energy-saving effect.

[0005] The utility model provides the following technical solution: a vacuum pipeline with a thermal barrier coating for high-temperature applications, the vacuum pipeline is used to connect the bottom of the single crystal furnace and the negative pressure device, and a thermal barrier coating is sprayed on the inner wall of the vacuum pipeline. The vacuum pipeline includes multiple vacuum tubes. The vacuum tube includes a first pipeline and a second pipeline. The second pipeline is connected to the side of the first pipeline. The second pipeline is connected to the negative pressure device through a pipeline. Both ends of the first pipeline are open. The upper end of the first pipeline is connected to the bottom of the single crystal furnace, and the lower end of the first pipeline is sealed by a head. A jacket is arranged on the outer surface of the upper end of the first pipeline, and a cooling water path is formed between the jacket and the first pipeline.

[0006] In order to make the vacuum degree of each vacuum tube the same, it further includes a third pipeline with both ends closed. The third pipeline is connected to the negative pressure device through a connecting pipeline. The second pipeline is connected to the side of the third pipeline, and a thermal barrier coating is also sprayed on the inner walls of the third pipeline and the connecting pipeline.

[0007] The composition of the thermal barrier coating is as follows. The thermal barrier coating contains oxides, and the oxides include zirconium oxide, yttrium oxide, aluminum oxide, tin oxide, and yttrium oxide.

[0008] The thermal barrier coating contains nitrides, and the nitrides include boron nitride, silicon nitride, and titanium nitride.

[0009] The thermal barrier coating contains titanium carbide.

[0010] The thermal barrier coating contains molybdenum silicide.

[0011] The thermal barrier coating contains zirconium boride.

[0012] The thermal barrier coating contains oxides, nitrides, titanium carbide, molybdenum silicide, zirconium boride, and mixtures of the above compounds.

[0013] Compared with the prior art, the beneficial effects achieved by the present utility model are as follows:

[0014] (1) By spraying a thermal barrier coating on the inner wall of the vacuum pipeline, the heat emitted by the molten silicon is isolated by the thermal barrier coating. When the high temperature of 1500 °C of the molten silicon is transmitted to the stainless steel surface through the thermal barrier coating, it is only 1250 °C, effectively reducing the safety hazard when the molten silicon leaks;

[0015] (2) The thermal barrier coating also plays a heat insulation role, improves the service environment of the vacuum pipeline, and extends its service life;

[0016] (3) The cooling water channel is arranged at the contact part between the vacuum pipeline and the furnace bottom plate to reduce the pipeline temperature of this part. Moreover, the setting of the thermal barrier coating can also effectively reduce the heat loss after the cooling water channel circulates, reduce the energy consumption, and has an energy-saving effect. At the same time, after the molten silicon leaks and causes reaction and ablation to the vacuum pipeline, the thermal barrier coating can isolate the heat of the molten silicon and reduce the risk caused by the molten silicon leakage. Description of the Drawings

[0017] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model, and do not constitute a limitation to the present utility model. In the drawings:

[0018] Figure 1 is the overall structural schematic diagram of the vacuum pipeline of the present utility model;

[0019] Figure 2 is the cross-sectional structural schematic diagram of the vacuum tube of the present utility model;

[0020] Figure 3 is the structural schematic diagram of the jacket of the vacuum tube of the present utility model;

[0021] In the figure: 1. Vacuum tube; 2. First pipeline; 3. Second pipeline; 4. Third pipeline; 5. Jacket; 6. Thermal barrier coating; 7. Connecting pipeline. Detailed implementation mode

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment

[0024] Please refer to Figures 1 to 3 , the present invention provides a technical solution: a vacuum pipeline with a thermal barrier coating for high-temperature applications. The vacuum pipeline is used to connect the bottom of the single crystal furnace and the negative pressure device. The inner walls of the vacuum pipeline are all sprayed with a thermal barrier coating 6. The thermal barrier coating 6 plays a heat insulation role, improves the service environment of the vacuum pipeline, extends the service life of the vacuum pipeline, and effectively isolates the heat emitted by the molten silicon. When the molten silicon leaks, the high temperature of 1500 °C of the molten silicon is transferred to the stainless steel surface through the thermal barrier coating and is only 1250 °C, effectively reducing the safety hazard when the molten silicon leaks.

[0025] As Figure 1 and 2 shown, the vacuum pipeline includes multiple vacuum tubes 1. The vacuum tube 1 includes a first pipeline 2 and a second pipeline 3. The second pipeline 3 is connected to the side of the first pipeline 2. The second pipeline 3 is connected to the negative pressure device through a pipeline. The negative pressure generated by the negative pressure device is used to evacuate the second pipeline 3 and the upper end of the first pipeline 2 in sequence, and finally the single crystal furnace is in a negative pressure working state. The first pipeline 2 is a straight pipe, and both ends of the first pipeline 2 are open. The first pipeline 2 with both ends open facilitates uniform spraying on the inner wall of the pipeline, so that the inner walls of the first pipeline 2 and the second pipeline 3 are both sprayed with a thermal barrier coating 6. The upper end of the first pipeline 2 is connected to the bottom of the single crystal furnace, and the lower end of the first pipeline 2 is sealed by a head.

[0026] It further includes a third pipeline 4 with both ends closed. The second pipeline 3 is connected to the side of the third pipeline 4. The third pipeline 4 is connected to the negative pressure device through a connecting pipeline 7, so that a negative pressure is generated inside the third pipeline 4. The inner walls of the third pipeline 4 and the connecting pipeline 7 are both sprayed with a thermal barrier coating 6. At the same time, the second pipelines 3 of multiple vacuum tubes 1 are connected to the third pipeline 4, so that the inside of multiple vacuum tubes 1 is maintained at the same negative pressure, and further multiple single crystal furnaces are maintained in the same negative pressure state, improving the product stability of different equipment production.

[0027] As Figure 3As shown, a jacket 5 is provided on the outer surface of the upper end of the first pipeline 2. A cooling water path is formed between the jacket 5 and the first pipeline 2. The cooling water path is located at the upper end of the first pipeline 2 to cool the contact part between the vacuum pipeline and the furnace bottom plate, greatly reducing the temperature of this contact part. At the same time, once the single crystal furnace has a thermal failure, the molten silicon will leak. The molten silicon will drip on the pipe wall of the vacuum pipeline, causing reaction and ablation to the pipe wall. At the same time, the thermal barrier coating 6 will isolate the heat of the molten silicon, reduce the temperature of the leaked molten silicon, and reduce the risk caused by the leakage.

[0028] The thermal barrier coating 6 is either an oxide, a nitride, titanium carbide, molybdenum silicide, zirconium boride, or a mixture of the above compounds. The oxides include zirconia, yttria, alumina, tin oxide, yttrium oxide. The nitrides include boron nitride, silicon nitride, titanium nitride.

[0029] In this embodiment, the spraying process of the vacuum pipeline is as follows:

[0030] First, pretreatment is carried out on the inner surface of the vacuum pipeline. The surface oil stains and other sundries are cleaned through acetone and alcohol. After completion, sandblasting treatment is carried out on the inner surface. The sandblasting pressure is 0.1 - 1 MPa, and the sandblasting material is white corundum grains with a mesh size of 30 - 100. After completion, spraying can be carried out;

[0031] Before spraying, the inner surface is preheated using a plasma flame to make the surface temperature reach 100 - 300 °C. First, an NiCrAlY metal powder is used to spray the intermediate layer with a thickness of 50 - 200 μm. After completion, the surface layer is sprayed;

[0032] ZrO2 - 8wt% Y2O3 nano - agglomerated zirconia powder is used for spraying with a thickness of 100 - 800 μm. The spraying process parameters are set as follows: current 300 - 800 A, power 20 - 60 KW, gun distance 50 - 120 mm, gun travel speed 200 - 800 mm / s, powder feeding rate 15 - 60 g / min, main gas flow rate 30 - 50 L / min;

[0033] After spraying, quality inspection is carried out. The appearance is continuously complete without defects such as cracks and delamination. It can be used only after passing the inspection.

[0034] Finally, it should be noted that the above - mentioned are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vacuum pipeline with a thermal barrier coating for high temperature applications, the vacuum pipeline is used to connect the bottom of a single crystal furnace and a negative pressure device, characterized in that: The inner wall of the vacuum pipeline is sprayed with a thermal barrier coating. The vacuum pipeline includes a plurality of vacuum tubes, and the vacuum tube includes a first pipeline and a second pipeline. The second pipeline is connected to the side of the first pipeline, and the second pipeline is connected to the negative pressure device through a pipeline. Both ends of the first pipeline are openings. The upper end of the first pipeline is connected to the bottom of the single crystal furnace, and the lower end of the first pipeline is sealed by a head. A jacket is provided on the outer surface of the upper end of the first pipeline, and a cooling water path is formed between the jacket and the first pipeline.

2. A vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: It also includes a third pipeline with closed ends, the third pipeline is connected to the negative pressure device through a connecting pipeline, the lower end of the second pipeline is connected to the side of the third pipeline, and the inner walls of the third pipeline and the connecting pipeline are also sprayed with a thermal barrier coating.

3. The vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: The thermal barrier coating comprises oxides, and the oxides include zirconium oxide, yttrium oxide, aluminum oxide, tin oxide, and yttrium oxide.

4. The vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: The thermal barrier coating comprises nitride, and the nitride comprises boron nitride, silicon nitride, and titanium nitride.

5. The vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: The thermal barrier coating comprises titanium carbide.

6. The vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: The thermal barrier coating comprises molybdenum silicide.

7. The vacuum pipeline with a thermal barrier coating for high temperature applications according to claim 1, characterized in that: The thermal barrier coating comprises zirconium boride.

8. A vacuum pipeline with a thermal barrier coating for high temperature applications according to any one of claims 3 to 7, characterized in that: The thermal barrier coating comprises oxide, nitride, titanium carbide, molybdenum silicide, zirconium boride and a mixture of the above compounds.

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