High-temperature measuring block and manufacturing process thereof

Abstract

The invention relates to the technical field of temperature measurement block production, in particular to a high-temperature temperature measurement block and a manufacturing process thereof. Wherein the temperature measuring block comprises a test piece, and the test piece comprises the following components in parts by weight: 60-95 parts of silicon carbide, 2-20 parts of aluminum nitride, 0-10 parts of boron carbide, 0-8 parts of yttrium oxide, 0-8 parts of aluminum oxide, 0-2 parts of carbon and 0-2 parts of boron. According to the invention, the formula and the proportion are improved to improve the upper limit of the measurement temperature of a test piece, so that the test piece can be applied to furnaces in vacuum of 1650-1900 DEG C and inert atmospheres of argon, nitrogen and the like; the reasonable size of the test piece for measuring the high-range temperature is obtained through repeated tests, and the variation of the size of the test piece along with the temperature change is reserved to the maximum degree on the premise that the occupied furnace space is as small as possible, so that the test piece has good temperature measurement accuracy and resolution.

Description

Technical Field

[0001] The invention relates to the technical field of temperature measuring block production, in particular to a high-temperature temperature measuring block and a manufacturing process thereof. Background Art

[0002] In the firing process of ceramics, in order to accurately measure the actual temperature changes in the kiln, temperature measuring blocks are placed at different positions in the kiln. The temperature measuring blocks absorb heat and shrink during the sintering process. As the sintering temperature increases and the insulation time increases, the total heat absorbed by the temperature measuring blocks increases, which makes the temperature measuring blocks shrink more and smaller in size after sintering. However, due to the limited composition and ratio of existing temperature measuring blocks, their temperature measurement range is between 500-1750℃, which makes it difficult to adapt to some high-temperature special ceramic industries such as silicon nitride, aluminum nitride, silicon carbide, boron carbide, etc. Therefore, a high-temperature temperature measuring block and its manufacturing process are needed to meet the temperature measurement requirements of higher temperature firing processes. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a high-temperature temperature measuring block and its manufacturing process, which has the advantages of a temperature measuring range of up to 1650-1900°C, accurate temperature measurement and convenient detection.

[0004] In a first aspect, the present invention provides a high-temperature temperature measuring block, comprising a test piece, the composition of which includes, by components: 60-95 parts of silicon carbide, 2-20 parts of aluminum nitride, 0-10 parts of boron carbide, 0-8 parts of yttrium oxide, 0-8 parts of aluminum oxide, 0-2 parts of carbon, and 0-2 parts of boron.

[0005] Furthermore, the test piece is a cube with a length of 20-26 mm, a width of 10-14 mm, and a thickness of 5-6 mm.

[0006] Furthermore, the temperature measuring block also includes a matching part, the bottom of the test piece is embedded in the matching part, the matching part includes a plurality of connecting rods and a sealing frame that are connected in a horizontal and vertical manner, the sealing frame is sleeved on the side wall of the test piece, the connecting rod is arranged below the test piece and its two ends extend upward along the side wall of the test piece to be connected to the matching part.

[0007] Furthermore, the sealing frame includes a base member and a protective layer covering the surface of the base member; wherein the base member is made of graphite, and the protective layer is an oxide.

[0008] Furthermore, the oxide is any one of magnesium oxide, zirconium oxide and aluminum oxide.

[0009] Furthermore, the melting point of the connecting rod material is greater than 1900°C.

[0010] In a second aspect, the present invention provides a high-temperature temperature measuring block manufacturing process, which is used to manufacture the temperature measuring block described above, wherein the manufacturing steps of the test piece include: S1: Weigh the raw materials of the test piece and an equal amount of deionized water according to the proportion and put them into a polyurethane ball mill for ball milling until the median particle size D50 of the raw materials is 0.5 μm-1.2 μm, then stop the ball milling to obtain a raw material mixed slurry; S2: Add 1-3 parts of polyvinyl alcohol to the raw material mixed slurry, stir evenly, spray granulate, and sieve to obtain a 100-300 mesh molding powder; S3: placing the molding powder in a mold for dry pressing until a test piece blank of a target size is obtained, and then heat treating the test piece blank to obtain a test piece.

[0011] Furthermore, in step S3, the maximum temperature of the heat treatment is set to 600 degrees and kept in the high temperature zone for 1 hour, and the heating rate is controlled to be 300°C / hour during the heating process.

[0012] Furthermore, in step S3, the dry-pressed test piece blank is first placed in the supporting part, and then heat-treated together with the supporting part.

[0013] Furthermore, in step S3, the test piece after the heat treatment is cooled first, and then the matching parts are installed.

[0014] By adopting the above technical solution, the beneficial effects of the present invention are: The present invention improves the formula and ratio to increase the upper limit of the measuring temperature of the temperature measuring block, so that the temperature measuring block can be applied to furnaces with vacuum and inert atmospheres such as argon and nitrogen at 1650-1900°C; after repeated tests, it is concluded that the temperature measuring block is a reasonable size for measuring a high range of temperature. Under the premise of occupying the furnace space as little as possible, the change in the volume of the temperature measuring block with the temperature change is maximized, so that the temperature measuring block has good temperature measurement accuracy and resolution. The matching parts are provided, which can not only limit and fix the test piece during the firing process of the test piece, but also provide continuous support and protection for the test piece during the test process because of its excellent thermal stability under high temperature conditions, increase the connection strength of the temperature measuring block, prevent deformation and cracking during the test process, facilitate the placement of the temperature measuring block, and ensure the accuracy of the measurement results. The oxide protective layer is covered on the base of the sealing frame graphite material to prevent the graphite from being oxidized during heat treatment, and at the same time prevent the graphite and the test piece from directly contacting and reacting during high-temperature sintering, which affects the temperature measurement results of the test piece.

[0015] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

[0016] Undoubtedly, these and other objects of the present invention will become more apparent after the following detailed description of the preferred embodiment described with reference to various figures and drawings.

[0017] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, one or several preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation of the present invention.

[0019] In the drawings, the same reference numerals are used for the same components and the drawings are schematic and not necessarily drawn to scale.

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one or several embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on such drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the overall structure of a high-temperature temperature measuring block of the present invention; Figure 2 This is an exploded view of the overall structure of a high-temperature temperature measuring block of the present invention; Figure 3 It is the test piece length-temperature corresponding curve.

[0022] Description of main reference numerals: 1. Test piece; 2. Accessories; 21. Connecting rod; 22. Seal the frame. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but are not used to limit the present invention.

[0024] First, refer to Figure 1-2 The present invention provides a technical solution: a high-temperature temperature measuring block. The temperature measuring block includes a test piece 1, and the composition of the test piece 1 includes: 60-95 parts of silicon carbide, 2-20 parts of aluminum nitride, 0-10 parts of boron carbide, 0-8 parts of yttrium oxide, 0-8 parts of aluminum oxide, 0-2 parts of carbon, and 0-2 parts of boron.

[0025] To facilitate subsequent measurement of the test piece 1 , the test piece 1 is a cube with a length of 20-26 mm, a width of 10-14 mm, and a thickness of 5-6 mm, preferably, a length of 23 mm, a width of 12 mm, and a thickness of 5.5 mm.

[0026] In order to prevent deformation and cracking of the test piece 1 when it shrinks and affect the measurement results, a matching part 2 is embedded at the bottom of the test piece 1. The matching part 2 includes a plurality of connecting rods 21 and a sealing frame 22 that are connected horizontally and vertically in an interlaced manner. The sealing frame 22 is sleeved on the side wall of the test piece 1. The sealing frame 22 includes a base member and a protective layer covering the surface of the base member; wherein the base member is made of graphite, and the protective layer is an oxide. The protective layer needs to have high temperature performance, so the oxide is any one of magnesium oxide, zirconium oxide and aluminum oxide. The connecting rod 21 is arranged below the test piece 1 and its two ends extend upward along the side wall of the test piece 1 to connect with the matching part 2. The melting point of the material of the connecting rod 21 is greater than 1900°, and can be any one of ultra-high temperature alloys, silicon carbide, zirconium diboride, etc.

[0027] In a second aspect, the present invention provides a high temperature temperature measuring block manufacturing process, which is used to manufacture the temperature measuring block described above. The manufacturing steps of the test piece 1 include: S1: Weigh the raw materials of the test piece and an equal amount of deionized water according to the proportion and put them into a polyurethane ball mill for ball milling. Silicon carbide grinding balls are used in the ball mill, and deionized water is used as the ball milling medium. The ball milling time is set to 5-10 hours and the rotation speed is 150-350r / min. Stop the ball milling after the median particle size D50 of the raw material is measured by a laser particle size analyzer to be 0.5μm-1.2μm to obtain a raw material mixed slurry.

[0028] S2: Add 1-3 parts of polyvinyl alcohol to the raw material mixed powder, stir evenly, spray granulate, and sieve to obtain a molding powder of 100-300 mesh.

[0029] S3: The molding powder is placed in a mold for dry pressing until a test piece of target size is obtained. The molding pressure is set at 120MPa-280MPa. The test piece is then heat treated to obtain a test piece. The maximum temperature during heat treatment is set to 600°C and kept in the high temperature zone for 1 hour. The heating rate is controlled at 300°C / hour during the heating process.

[0030] Optionally, in step S3, the test piece after the heat treatment is cooled first, and then the supporting parts are installed. The supporting parts can be assembled as needed to increase the flexibility of use.

[0031] Optionally, in order to improve the success rate of the test piece in the heat treatment process, in step S3, the dry-pressed test piece blank is first placed in the supporting part 2 and then heat-treated together with the supporting part 2. Example 1

[0032] Weigh 1.43Kg of silicon carbide, 0.24Kg of aluminum nitride, 0.1Kg of boron carbide, 0.12Kg of yttrium oxide, 0.08Kg of aluminum oxide, 0.02Kg of carbon, and 0.01Kg of boron as raw materials, wherein the purity of the raw materials used is greater than or equal to 99%. Use silicon carbide grinding balls and an equal amount of deionized water as the ball milling medium, and ball mill for 8 hours at a speed of 300 r / min. Use a laser particle size analyzer to measure the particle size distribution of the slurry, and the median particle size D50 is 0.65um. Then add polyvinyl alcohol with a weight ratio of 1.5%, stir evenly, spray, granulate, and control the outlet temperature at 120°C. The powder obtained by spraying is sieved to obtain a molding powder of 100 mesh-300 mesh.

[0033] The molding powder was put into the designed mold and dry pressed to obtain the ceramic test piece embryo. The molding pressure was 150MPa and the holding time was 5s. The dimensions of the test piece 1 were: length 23mm, width 12mm, thickness 5.5mm.

[0034] The test piece blank is placed in a kiln for heat treatment to remove the binder. The kiln is set to a maximum temperature of 600 degrees, a heating rate of 300 degrees per hour, a high temperature zone insulation time of 1 hour, and an air atmosphere, so that the PVA added during the molding of the test piece 1 is decomposed and discharged. The cooled test piece 1 is assembled with the matching parts to form a temperature measuring block before use. Example 2

[0035] The difference between this embodiment and embodiment 1 is that in this embodiment, after the molding powder is dry-pressed, the test piece blank is first placed in the matching part 2 and then heat treated.

[0036] The test effect of the temperature measuring block was tested. 180 temperature measuring blocks mentioned in Example 1 were randomly selected as samples for comparative sintering at different temperatures. The experimental steps were as follows: Set the maximum sintering temperature in the kiln to a range of 1650-1900°C, then take a temperature point every 10°C, take 2 temperature measuring blocks at each temperature point and place them side by side in the kiln near the temperature measuring end of the thermocouple for sintering. During the sintering process, set the heating rate to 300°C / hour, the maximum temperature holding time to 2 hours, the cooling rate to 300°C / hour, and introduce flowing argon gas into the kiln for protection. When the temperature in the kiln cools to room temperature, take out the temperature measuring block, let it stand for 1 hour, take out the test piece, and finally measure the length of the test piece (that is, the length of the temperature measuring block) with a vernier caliper. Repeat the above operation 3 times at one temperature point, so that 6 test piece lengths and their corresponding temperature data can be obtained at each temperature point, and then take the average value and fit it to obtain the test piece length-temperature correspondence curve, refer to Figure 3 , where the Y axis represents the length of the test piece after sintering, and the X axis represents the sintering temperature. From the curve, we can see that the test piece continues to shrink in the temperature range of 1650℃-1900℃. The higher the temperature, the greater the corresponding shrinkage, and the shorter the length of the test piece after sintering. Then, after data processing, we can get Table 1.

[0037] Table 1 Test piece length-temperature comparison table

[0038] According to the above table, it can be seen that the length of each temperature measuring block after sintering will correspond to a sintering temperature.

[0039] Therefore, it can be concluded that the temperature measuring block in the present invention can be used in the temperature measurement of kilns protected by vacuum or inert atmospheres such as argon and nitrogen in the temperature range of 1650-1900℃. The user places the temperature measuring block product at the position where the temperature needs to be measured in the kiln, and sintering is carried out simultaneously with the product. After cooling, the length of the temperature measuring block is measured, and then converted into the corresponding temperature. The actual temperature of the kiln at that position can be obtained, and the actual heating conditions of the product can be understood. It helps to monitor and control the temperature of the sintering of products in the high-temperature special ceramic industry such as silicon nitride, aluminum nitride, silicon carbide, and boron carbide, optimize the sintering process parameters, improve product performance, save energy, reduce emissions, and reduce costs.

[0040] It should be understood that the embodiments disclosed in the present invention are not limited to the specific processing steps or materials disclosed herein, but should be extended to equivalent substitutions of such features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0041] The "embodiment" mentioned in the specification means that the specific features or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0042] In addition, the described features or characteristics may be combined in one or more embodiments in any other suitable manner. In the above description, some specific details, such as thickness, quantity, etc., are provided to provide a comprehensive understanding of the embodiments of the present invention. However, those skilled in the relevant art will understand that the present invention can be implemented without one or more of the above specific details or can also be implemented using other methods, components, materials, etc.

Claims

1. A high temperature temperature measuring block, characterized in that: The test piece comprises the following components: 60-95 parts of silicon carbide, 2-20 parts of aluminum nitride, 0-10 parts of boron carbide, 0-8 parts of yttrium oxide, 0-8 parts of aluminum oxide, 0-2 parts of carbon, and 0-2 parts of boron.

2. The high temperature measuring block according to claim 1, characterized in that: The test piece is a cube with a length of 20-26 mm, a width of 10-14 mm, and a thickness of 5-6 mm.

3. The high temperature measuring block according to claim 1, characterized in that: It also includes a matching piece, the bottom of the test piece is embedded in the matching piece, the matching piece includes a plurality of connecting rods and a sealing frame that are connected in a horizontal and vertical manner, the sealing frame is sleeved on the side wall of the test piece, the connecting rods are arranged below the test piece and the two ends thereof extend upward along the side wall of the test piece to be connected to the matching piece.

4. The high temperature measuring block according to claim 3, characterized in that: The sealing frame comprises a base member and a protective layer covering the surface of the base member; wherein the base member is made of graphite and the protective layer is made of oxide.

5. The high temperature measuring block according to claim 4, characterized in that: The oxide is any one of magnesium oxide, zirconium oxide and aluminum oxide.

6. The high temperature measuring block according to claim 3, characterized in that: The melting point of the connecting rod material is greater than 1900°C.

7. A high temperature measuring block manufacturing process, used to manufacture the measuring block as claimed in claim 3, characterized in that: The steps for making the test piece include: S1: Weigh the raw materials of the test piece and an equal amount of deionized water according to the proportion and put them into a polyurethane ball mill for ball milling until the median particle size D50 of the raw materials is 0.5 μm-1.2 μm, then stop the ball milling to obtain a raw material mixed slurry; S2: Add 1-3 parts of polyvinyl alcohol to the raw material mixed slurry, stir evenly, spray granulate, and sieve to obtain a 100-300 mesh molding powder; S3: placing the molding powder in a mold for dry pressing until a test piece blank of a target size is obtained, and then heat treating the test piece blank to obtain a test piece.

8. The high temperature measuring block manufacturing process according to claim 7, characterized in that: In step S3, the maximum temperature of the heat treatment is set to 600°C and maintained at the maximum temperature for 1 hour, and the heating rate is controlled to 300°C / hour during the heating process.

9. The high temperature measuring block manufacturing process according to claim 7, characterized in that: In step S3, the dry-pressed test piece blank is first placed in the supporting part, and then heat-treated together with the supporting part.

10. The high temperature measuring block manufacturing process according to claim 7, characterized in that: In step S3, the test piece after the heat treatment is cooled first, and then the matching parts are installed.

Images