Low-temperature glass sealing material for thermocouple and preparation method of low-temperature glass sealing material

Abstract

The invention relates to the technical field of temperature sensing assemblies, and discloses a low-temperature glass sealing material for a thermocouple and a preparation method thereof.The low-temperature glass sealing material is obtained by taking bismuth oxide, boric oxide, barium oxide, silicon dioxide, aluminum oxide and copper oxide as raw materials, mixing, grinding and sintering the components and then crushing and grinding the components. The softening point of the low-temperature glass sealing material is about 517 DEG C, a good sealing effect can be formed at the temperature of 600-700 DEG C, the influence of high-temperature sealing on thermocouple element precision and mechanical properties of the material can be avoided, and the low-temperature glass sealing material has a good fixing effect, can meet the glass sealing requirements of a thermocouple under medium and low temperature conditions, and also has an insulating property; in addition, the preparation process of the low-temperature glass sealing material is simple and practical, the manufacturability is high, and batch production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of temperature sensing components and discloses a low-temperature glass sealing material for a thermocouple and a preparation method thereof. Background Art

[0002] During the temperature measurement process of the assembled thermocouple sensor of an aircraft engine, in order to ensure the stability of the fixing strength and insulation performance of the temperature measuring end wire in harsh operating environments, the working end needs to be bonded and fixed.

[0003] The operating environment of aircraft engine thermocouples is characterized by high temperature and strong vibration. When the operating temperature of the thermocouple is lower than 300°C, epoxy sealing is used; when the temperature is greater than 350°C, glass sealing is used; since the sealing temperature of most glasses is as high as 900°C, for thermocouples with a wire diameter of less than 0.5mm, this temperature condition basically reaches its upper limit of use. When the sealing temperature is higher than 900°C, the glass sealing material is likely to affect the accuracy and performance of the thermocouple. Summary of the invention

[0004] The object of the present invention is to provide a low-temperature glass sealing material for a thermocouple and a preparation method thereof, which can meet the glass sealing requirements of the thermocouple under medium and low temperature conditions.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A low-temperature glass sealing material for a thermocouple is mainly obtained by mixing, grinding, sintering, and then crushing and grinding bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide raw materials.

[0007] Furthermore, in terms of mass percentage, the raw material components of the low-temperature glass sealing material are:

[0008] Bismuth oxide 40~70%

[0009] Boron oxide 12~25%

[0010] Barium oxide 10~25%

[0011] Silicon dioxide 0.5~5%

[0012] Aluminum oxide 0.5~3%

[0013] Copper oxide 0.4~5%.

[0014] Furthermore, in the low-temperature glass sealing material, the bismuth oxide content is 60%, the boron oxide content is 18.8%, the barium oxide content is 15.0%, the silicon dioxide content is 3%, the aluminum oxide content is 1.2%, and the copper oxide content is 2%.

[0015] In order to achieve the above technical effects, the present invention also provides a method for preparing a low-temperature glass sealing material for a thermocouple, which is used to prepare the low-temperature glass sealing material for a thermocouple, comprising:

[0016] Step 1: Mix and grind bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide to form a mixed powder;

[0017] Step 2: Take half of the mixed powder and sinter it at 1100-1110° C. for 15-20 minutes, then take it out and cool it to room temperature in air;

[0018] Step 3: Mix the remaining mixed powder with the powder cooled after the first sintering, sinter at 1100-1110° C. for 15-20 minutes to form a molten glass body, then take it out and cool it in air for 1-2 minutes;

[0019] Step 4: quickly immerse the molten glass into water, take it out after cooling, and dry the glass;

[0020] Step 5: crush the glass body and grind it into particles with a particle size ranging from 50 to 200 meshes to obtain the low-temperature glass sealing material.

[0021] Furthermore, in the step 1, the amount of bismuth oxide is 40-70%, the amount of boron oxide is 12-25%, the amount of barium oxide is 10-25%, the amount of silicon dioxide is 0.5-5%, the amount of aluminum oxide is 0.5-3%, and the amount of copper oxide is 0.4-5%.

[0022] Furthermore, in the step 4, the glass body is dried at 120°C.

[0023] Furthermore, in the step 5, the crushed glass body is placed in a ball mill container, and a proper amount of ceramic grinding bodies are added, and mixed and ground for 4 to 8 hours to obtain the low-temperature glass sealing material.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The low-temperature glass sealing material of the present invention has a softening point of about 517°C, and can form a good sealing effect at 600°C to 700°C, which can avoid the influence of high-temperature sealing on the accuracy of thermocouple elements and the mechanical properties of materials, and has a good fixing effect. While having both insulating properties, it can also meet the glass sealing requirements of thermocouples under medium and low temperature conditions.

[0026] 2. The preparation process of the low-temperature glass sealing material of the present invention is simple and practical, has strong processability, and is convenient for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Flow chart of the preparation method of low-temperature glass sealing material for thermocouple in the embodiment. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the embodiments and drawings. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0029] Example

[0030] A low-temperature glass sealing material for a thermocouple is mainly obtained by mixing, grinding, sintering, and then crushing and grinding bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide raw materials.

[0031] See also Figure 1 The preparation method of the low-temperature glass sealing material for the thermocouple in this embodiment is as follows:

[0032] Step 1: Mix and grind bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide to form a mixed powder;

[0033] In this embodiment, the amount of bismuth oxide Bi2O3 is 60%, the amount of boron oxide B2O3 is 18.8%, the amount of barium oxide BaO is 15%, the amount of silicon dioxide SiO2 is 3%, the amount of aluminum oxide Al2O3 is 1.2%, and the amount of copper oxide CuO is 2%.

[0034] Step 2: Take half of the mixed powder and sinter it at 1100-1110° C. for 15-20 minutes, then take it out and cool it to room temperature in air;

[0035] Step 3: Mix the remaining mixed powder with the powder cooled after the first sintering, sinter at 1100-1110° C. for 15-20 minutes to form a molten glass body, then take it out and cool it in air for 1-2 minutes;

[0036] Step 4: quickly immerse the molten glass into water, take it out after cooling, and dry the glass at 120°C;

[0037] Step 5: crush the glass body and grind it into particles with a particle size of 50 to 200 meshes. In the grinding process of this embodiment, the crushed glass body is placed in a ball mill container, and a proper amount of ceramic grinding bodies are added, and the low-temperature glass sealing material is obtained by mixing and grinding for 4 to 8 hours.

[0038] The preparation process of the low-temperature glass sealing material in this embodiment is simple and practical, has strong processability, and is convenient for mass production.

[0039] Through testing, the softening point of the low-temperature glass sealing material prepared in this embodiment is 517°C, which can avoid the influence of high temperature on the accuracy of thermocouple elements and mechanical properties of materials when high-temperature sealing (sealing temperature is greater than 850°C) is required; in addition, the expansion coefficient of the material is 1.098×10 -5 / ℃, can form a good sealing effect with high-temperature alloy 3039, alumina ceramic tube and thermocouple wire materials, can withstand 0.5MPa air pressure sealing for a long time, and has the advantages of low sealing temperature, high temperature resistance, stable and good insulation and fixing effect, etc.

[0040] In summary, this embodiment uses bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide as raw materials, mixes the components, grinds and sinters, and then crushes and grinds to obtain the low-temperature glass sealing material. The low-temperature glass sealing material has a softening point of about 517°C, and can form a good sealing effect at 600°C to 700°C. It can avoid the influence of high-temperature sealing on the accuracy of thermocouple elements and the mechanical properties of materials, and has a good fixing effect. While having insulating properties, it can also meet the glass sealing requirements of thermocouples under medium and low temperature conditions.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-temperature glass sealing material for thermocouples, characterized in that: The low-temperature glass sealing material is mainly obtained by mixing, grinding, sintering, and then crushing and grinding bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide.

2. The low-temperature glass sealing material for thermocouple according to claim 1, characterized in that: In terms of mass percentage, the raw material components of the low-temperature glass sealing material are:

3. The low-temperature glass sealing material for thermocouple according to claim 2, characterized in that: The low-temperature glass sealing material contains 60% bismuth oxide, 18.8% boron oxide, 15.0% barium oxide, 3% silicon dioxide, 1.2% aluminum oxide and 2% copper oxide.

4. A method for preparing a low-temperature glass sealing material for a thermocouple, used for preparing the low-temperature glass sealing material for a thermocouple according to claim 1, characterized in that: include: Step 1: Mix and grind bismuth oxide, boron oxide, barium oxide, silicon dioxide, aluminum oxide, and copper oxide to form a mixed powder; Step 2: Take half of the mixed powder and sinter it at 1100-1110° C. for 15-20 minutes, then take it out and cool it to room temperature in air; Step 3: Mix the remaining mixed powder with the powder cooled after the first sintering, sinter at 1100-1110° C. for 15-20 minutes to form a molten glass body, then take it out and cool it in air for 1-2 minutes; Step 4: quickly immerse the molten glass into water, take it out after cooling, and dry the glass; Step 5: crush the glass body and grind it into particles with a particle size ranging from 50 to 200 meshes to obtain the low-temperature glass sealing material.

5. The method for preparing a low-temperature glass sealing material for a thermocouple according to claim 4, characterized in that: In the step 1, the amount of bismuth oxide is 40-70%, the amount of boron oxide is 12-25%, the amount of barium oxide is 10-25%, the amount of silicon dioxide is 0.5-5%, the amount of aluminum oxide is 0.5-3%, and the amount of copper oxide is 0.4-5%.

6. The method for preparing a low-temperature glass sealing material for a thermocouple according to claim 4, characterized in that: In the step 4, the glass body is dried at 120°C.

7. The method for preparing a low-temperature glass sealing material for a thermocouple according to claim 4, characterized in that: In the step 5, the broken glass body is placed in a ball mill container, and a proper amount of ceramic grinding bodies are added, and mixed and ground for 4 to 8 hours to obtain the low-temperature glass sealing material.

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