High thermal shock resistance ceramic and process for its preparation

Abstract

The application discloses high-thermal-shock-resistance ceramic and a preparation process thereof, and belongs to the technical field of ceramic preparation. The application discloses how to further improve the thermal shock resistance of ceramic. The application comprises the following components in percentage by mass: 40-50% of green body raw clay powder, 5-15% of alumina powder, 4-8% of micron-sized cerium oxide, 3-5% of nano-sized cerium oxide, and 30-40% of a solvent. When the preparation is performed, the green body raw clay is cut into blocks to obtain clay blocks. After the clay blocks are dried, the clay blocks are crushed to obtain the green body raw clay powder. Then, various raw materials are added into a wet ball mill for ball milling. Then, the nano-sized cerium oxide is added into the wet ball mill for continuous ball milling to obtain premix. The premix is added into a gypsum mold and dried to obtain a green body. The green body after drying is sintered to obtain a ceramic product. The application controls the particle sizes of the micron-sized cerium oxide and the nano-sized cerium oxide, so that the obtained ceramic structure is dense, and the thermal shock resistance of the ceramic is improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic preparation technology, specifically relating to a high thermal shock resistant ceramic and its preparation process. Background Technology

[0002] Huili green pottery gets its name from the malachite used in its ingredients. The products are a vibrant emerald green, with a clean and elegant appearance, and produce a clear, metallic sound when struck. It boasts a history of over 800 years. In 2009, it was included in the second batch of Sichuan Provincial Intangible Cultural Heritage List, becoming a unique industry of Huili County, Liangshan Prefecture. However, Huili green pottery itself has poor properties, with low thermal shock resistance and bending strength, which greatly limits its application and hinders its development.

[0003] The prior art patent CN 109761580 A provides a processing technology for Huili ceramics that can improve thermal shock resistance. It improves the thermal shock resistance and bending resistance of ceramic products to a certain extent by adding a certain amount of aluminum oxide, cerium dioxide and titanium dioxide. On this basis, how to further improve the thermal shock resistance of ceramics is a question that needs to be explored. Summary of the Invention

[0004] To address the issue of how to further improve the thermal shock resistance of ceramics in existing technologies, this invention provides a high thermal shock resistance ceramic and its preparation process.

[0005] The technical solution adopted in this invention is as follows:

[0006] A highly thermally shock resistant ceramic, comprising the following components by weight percentage:

[0007] 40-50% raw clay powder, 5-15% alumina powder, 4-8% micron-sized cerium oxide, 3-5% nano-sized cerium oxide, and 30-40% solvent.

[0008] By adopting this technical solution, the present invention controls the particle size of the added micron-sized and nano-sized cerium oxide, resulting in ceramics with smaller pores and denser structure, thereby improving the thermal shock resistance of the ceramics.

[0009] Preferably, the solvent is water, and boehmite alumina powder is added to the water, with the mass ratio of boehmite alumina powder to water being 1:10-15.

[0010] After adopting this technical solution, boehmite alumina powder is mixed with water to obtain a suspension. This suspension has a certain viscosity, which can improve the compatibility between the components and make the various raw materials uniformly mixed, thereby further improving the thermal shock resistance.

[0011] Preferably, the nano-sized cerium oxide has a particle size of 10-20 nm, and the micron-sized cerium oxide includes coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide. The mass ratio of the coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide is 1:1-2:1-2. The particle size of the coarse-grained micron-sized cerium oxide is 50-40 μm, the particle size of the medium-grained micron-sized cerium oxide is 40-30 μm, and the particle size of the fine-grained micron-sized cerium oxide is 30-20 μm.

[0012] After adopting this technical solution, the particle size of micron-sized cerium oxide decreases in a stepwise manner. Coarse-sized micron-sized cerium oxide can be uniformly filled into the gaps between the raw clay powder particles of the billet, medium-sized micron-sized cerium oxide can be uniformly filled into the gaps between coarse-sized micron-sized cerium oxide and the raw clay powder particles of the billet, and fine-sized micron-sized cerium oxide can be uniformly filled into the gaps between coarse-sized and medium-sized micron-sized cerium oxide. This results in a compact structure of the final green body, which is less prone to cracking during sintering.

[0013] Preferably, the particle size of the raw clay powder is less than or equal to 75 μm.

[0014] Preferably, the mass ratio of micron-sized cerium oxide to nano-sized cerium oxide is 2:1-0.5.

[0015] By adopting this technical solution, nano-sized cerium oxide can fill the tiny gaps between various raw materials, further improving the compactness of the preform.

[0016] A process for preparing a ceramic with high thermal shock resistance includes the following steps:

[0017] Step A: Cut the raw clay into blocks to obtain clay blocks. After the clay blocks are dried, crush them to obtain raw clay powder.

[0018] Step B: Add 40-50% of the raw material mud powder, 5-10% of the alumina powder, 4-8% of the micron-sized cerium oxide, and 30-40% of the solvent to a wet ball mill and ball mill for 6-10 hours.

[0019] Step C: Add 3-5% nano-sized cerium oxide to a wet ball mill and continue ball milling for 1-3 hours to obtain a premix;

[0020] Step D: Add the premixed material into the plaster mold and allow it to dry and plasticize to obtain the green body;

[0021] Step F: Sinter the dried and plasticized green body to obtain ceramic products.

[0022] By adopting this technical solution, various raw materials can be ball-milled, which can improve the dispersion effect of the components and thus make the components uniformly mixed.

[0023] Preferably, the solvent in step B is prepared by adding boehmite alumina powder and water into a stirring mechanism and stirring for 20-40 minutes to obtain the solvent.

[0024] Preferably, the micron-sized cerium oxide in step B includes coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide, with a mass ratio of 1:1-2:1-2. The particle size of the coarse-grained micron-sized cerium oxide is 50-40 μm, the particle size of the medium-grained micron-sized cerium oxide is 40-30 μm, and the particle size of the fine-grained micron-sized cerium oxide is 30-20 μm. The specific steps of step B are as follows:

[0025] Step B1: Add 40-50% of the raw material mud powder, 5-10% of the alumina powder and 30-40% of the solvent to a wet ball mill and ball mill for 1-2 hours;

[0026] Step B2: Add coarse-grained micron-sized cerium oxide and continue grinding for 1-2 hours;

[0027] Step B3: Add medium-sized micron-sized cerium oxide and continue grinding for 1-2 hours;

[0028] Step B4: Add fine-grained, micron-sized cerium oxide and continue grinding for 1-2 hours.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. In this invention, by controlling the particle size of the added micron-sized and nano-sized cerium oxide, the resulting ceramic has smaller pores and a denser structure, thereby improving the ceramic's thermal shock resistance.

[0031] 2. In this invention, boehmite alumina powder is mixed with water to obtain a suspension. This suspension has a certain viscosity, which can improve the compatibility between the components and make the various raw materials uniformly mixed, thereby further improving the thermal shock resistance.

[0032] 3. In this invention, boehmite alumina transforms into more structurally stable α-Al2O3 during calcination, resulting in a denser sintered ceramic structure and further improving the ceramic's thermal shock resistance.

[0033] 3. In this invention, the particle size of micron-sized cerium oxide decreases in a stepwise manner. Coarse-sized micron-sized cerium oxide can be uniformly filled into the gaps between the raw clay powder particles of the billet, medium-sized micron-sized cerium oxide can be uniformly filled into the gaps between coarse-sized micron-sized cerium oxide and the raw clay powder particles of the billet, and fine-sized micron-sized cerium oxide can be uniformly filled into the gaps between coarse-sized and medium-sized micron-sized cerium oxide. This results in a compact structure of the final green body, which is less prone to cracking during sintering. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0035] Example 1

[0036] A high thermal shock resistant ceramic comprises, by weight percentage: 500g of raw clay powder, 110g of alumina powder, 60g of micron-sized cerium oxide, 30g of nano-sized cerium oxide, and 300g of solvent.

[0037] In this embodiment, the raw clay powder is taken from Baini Mountain in Huili, and its main component is white clay.

[0038] In this embodiment, the solvent is water, and boehmite alumina powder is added to the water. The mass ratio of the boehmite alumina powder to the water is 1:10.

[0039] In this embodiment, the particle size of the boehmite alumina powder is 15 nm.

[0040] In this embodiment, the nano-sized cerium oxide has a particle size of 15 nm, and the micron-sized cerium oxide includes coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide. The mass ratio of the coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide is 1:1:1. The coarse-grained micron-sized cerium oxide has a particle size of 50 μm, the medium-grained micron-sized cerium oxide has a particle size of 40 μm, and the fine-grained micron-sized cerium oxide has a particle size of 30 μm.

[0041] In this embodiment, the particle size of the raw clay powder is 75 μm.

[0042] In this embodiment, the mass ratio of micron-sized cerium oxide to nano-sized cerium oxide is 2:1.

[0043] Example 2

[0044] This embodiment describes the preparation method of the high thermal shock resistant ceramic of Example 1, including the following steps:

[0045] Step A: Cut the raw clay into blocks to obtain clay blocks, then air dry them to remove moisture and dry them completely. Then crush them and collect the powder through a sieve for later use.

[0046] Step B: Add boehmite alumina powder with a particle size of 15nm and water to a mixer at a ratio of 1:10 and stir for 30 minutes to obtain a solvent. Weigh out 500g of raw clay powder, 110g of alumina powder, 60g of micron-sized cerium oxide, and 300g of solvent, and add them to a wet ball mill for ball milling for 6 hours; specifically:

[0047] Step B1: Add 500g of raw clay powder, 100g of alumina powder and 300g of solvent to a wet ball mill and ball mill for 1 hour;

[0048] Step B2: Add 20g of coarse-grained micron-sized cerium oxide and continue grinding for 1 hour;

[0049] Step B3: Add 20g of medium-sized micron-sized cerium oxide and continue grinding for 1 hour;

[0050] Step B4: Add 20g of fine-grained micron-sized cerium oxide and continue grinding for 1 hour;

[0051] Step C: Add 30g of nano-sized cerium oxide to a wet ball mill and continue ball milling for 2 hours to obtain a premix;

[0052] Step D: Add the premixed material into the plaster mold and allow it to dry and plasticize to obtain the green body;

[0053] Step F: Use a blower to clean the impurities on the surface of the blank, place it in a muffle furnace, and sinter it under normal pressure at a temperature of 1260℃ for 13 hours. The specific sintering parameters are as follows: the initial temperature of the muffle furnace is 50℃, after 100 minutes it is raised to 400℃ and held at 400℃ for 90 minutes; after another 110 minutes it is raised to 950℃ and held for 120 minutes; after another 40 minutes it is raised to 1150℃ and held for 85 minutes; after another 42 minutes it is raised to 1260℃ and held for 180 minutes; turn off the power, cool it in the furnace to about 200℃, and then take it out to cool naturally to complete the production.

[0054] Example 3

[0055] This embodiment is basically the same as Embodiment 1, except that, by mass percentage, it includes the following components: 500g of raw clay powder, 80g of alumina powder, 80g of micron-sized cerium oxide, 40g of nano-sized cerium oxide, and 300g of solvent.

[0056] Example 4

[0057] This embodiment is basically the same as Embodiment 1, except that, by mass percentage, it includes the following components: 500g of raw clay powder, 100g of alumina powder, 40g of micron-sized cerium oxide, 60g of nano-sized cerium oxide, and 300g of solvent.

[0058] Comparative Example 1

[0059] This comparative example is basically the same as Example 2, except that: no nano-sized cerium oxide is added in this comparative example.

[0060] Comparative Example 2

[0061] This comparative example is basically the same as Example 2, except that micron-sized cerium oxide is not added to this comparative example.

[0062] Comparative Example 3

[0063] This comparative example is basically the same as Example 2, except that the solvent in this comparative example contains only water and does not contain boehmite alumina powder.

[0064] Comparative Example 4

[0065] This comparative example is basically the same as Example 2, except that the micron-sized cerium oxide in this comparative example has only one particle size, which is 50 μm.

[0066] Comparative Example 5

[0067] This comparative example is basically the same as Example 2, except that: in this comparative example, 500g of raw clay powder, 110g of alumina powder, 60g of micron-sized cerium oxide of all particle sizes and 300g of solvent were ground for 4 hours, and then nano-sized cerium oxide was added and ground for 2 hours.

[0068] Comparative Example 6

[0069] This comparative example is basically the same as Comparative Example 6, except that in this comparative example, 500g of raw clay powder, 110g of alumina powder, 60g of micron-sized cerium oxide of all particle sizes, 30g of nano-sized cerium oxide, and 300g of solvent were ground together for 6 hours.

[0070] The ceramics obtained in Examples 2-4 and Comparative Examples 1-6 were subjected to performance testing, and the test results are shown in Table 1.

[0071] Table 1

[0072]

[0073] As can be seen from Table 1, by adding micron-sized cerium oxide and nano-sized cerium oxide, and setting the micron-sized cerium oxide to three particle sizes (coarse, medium, and fine), and by setting the three particle sizes to vary in a stepwise manner, the density between the green bodies is effectively improved, which can improve the thermal shock resistance of ceramics.

[0074] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A ceramic with high thermal shock resistance, characterized in that: It comprises the following components by weight percentage: 40-50% raw clay powder, 5-15% alumina powder, 4-8% micron-sized cerium oxide, 3-5% nano-sized cerium oxide, and 30-40% solvent; the raw clay powder is taken from Baini Mountain in Huili, which includes white clay. The solvent is water, and boehmite alumina powder is added to the water. The mass ratio of the boehmite alumina powder to the water is 1:10-15. The particle size of the boehmite alumina powder is 10-15 nm; The nano-sized cerium oxide has a particle size of 10-20 nm. The micron-sized cerium oxide includes coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide. The mass ratio of the coarse-grained micron-sized cerium oxide, medium-grained micron-sized cerium oxide, and fine-grained micron-sized cerium oxide is 1:1-2:1-2. The particle size of the coarse-grained micron-sized cerium oxide is 50-40 μm, the particle size of the medium-grained micron-sized cerium oxide is 40-30 μm, and the particle size of the fine-grained micron-sized cerium oxide is 30-20 μm. The raw clay powder, alumina powder, micron-sized cerium oxide, and nano-sized cerium oxide are mixed according to the following steps to obtain a premix: Add 40-50% of the raw mud powder, 5-15% of the alumina powder and 30-40% of the solvent to a wet ball mill and ball mill for 1-2 hours. Add coarse-grained micron-sized cerium oxide and continue grinding for 1-2 hours; Add medium-sized micron-sized cerium oxide and continue grinding for 1-2 hours; Add fine-particle-size (micron-sized) cerium oxide and continue grinding for 1-2 hours; Add 3-5% nano-sized cerium oxide to a wet ball mill and continue ball milling for 1-3 hours to obtain a premix.

2. The high thermal shock resistant ceramic according to claim 1, characterized in that: The particle size of the raw clay powder is less than or equal to 75 μm.

3. A preparation process for a high thermal shock resistant ceramic as described in any one of claims 1-2, characterized in that: Includes the following steps: Step A: Cut the raw clay into blocks to obtain clay blocks. After the clay blocks are dried, crush them to obtain raw clay powder. Step B: Add 40-50% of the raw clay powder, 5-15% of alumina powder, 4-8% of micron-sized cerium oxide, and 30-40% of solvent to a wet ball mill for ball milling. The micron-sized cerium oxide includes coarse-diameter, medium-diameter, and fine-diameter micron-sized cerium oxide, with a mass ratio of 1:1-2:1-2. The particle size of the coarse-diameter cerium oxide is 50-40 μm, the medium-diameter cerium oxide is 40-30 μm, and the fine-diameter cerium oxide is 30-20 μm. The specific steps of Step B are as follows: Step B1: Add 40-50% of the raw mud powder, 5-15% of the alumina powder and 30-40% of the solvent to a wet ball mill and ball mill for 1-2 hours; Step B2: Add coarse-grained micron-sized cerium oxide and continue grinding for 1-2 hours; Step B3: Add medium-sized micron-sized cerium oxide and continue grinding for 1-2 hours; Step B4: Add fine-grained, micron-sized cerium oxide and continue grinding for 1-2 hours; Step C: Add 3-5% nano-sized cerium oxide to a wet ball mill and continue ball milling for 1-3 hours to obtain a premix; Step D: Add the premixed material into the plaster mold and allow it to dry and plasticize to obtain the green body; Step F: Sinter the dried and plasticized green body to obtain ceramic products.

4. The preparation process of a high thermal shock resistant ceramic according to claim 3, characterized in that: The solvent in step B is prepared by adding boehmite alumina powder and water into a stirring mechanism and stirring for 20-40 minutes to obtain the solvent.

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