A high-strength cordierite-mullite ceramic tube and its preparation process

Abstract

This application relates to the technical field of ceramic tube preparation, and specifically discloses a high-strength cordierite-mullite ceramic tube and its preparation process. The ceramic tube comprises the following raw materials: mullite, cordierite, alumina, and a sintering aid. Its preparation process includes: S1. Mix and stir the raw materials by weight to obtain a mixture; S2. Place the mixture in an isostatic pressing device for pressing to obtain a green body of the ceramic tube; S3. Perform pre-sintering treatment on the green body of the ceramic tube, and obtain a pre-sintered ceramic tube blank after natural cooling; S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method, place it in a curing solution for vacuum infiltration and curing after coating, take it out and dry it to obtain a coated ceramic tube blank; S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The cordierite-mullite ceramic tube prepared by this application has the beneficial effects of high stability, high strength, and high toughness.

Description

Technical Field

[0001] This application relates to the technical field of ceramic tube preparation, and more specifically, it relates to a high-strength cordierite-mullite ceramic tube and its preparation process. Background Art

[0002] Ceramic materials are a class of inorganic non-metallic materials made from natural or synthetic compounds through forming and high-temperature sintering. A ceramic tube is a tubular device made of ceramic materials. Due to the unique physical and chemical properties of ceramic materials themselves, ceramic tubes have a wide range of applications in many fields, such as electronic components, chemical industry, medical treatment, mechanical manufacturing, etc.

[0003] Ceramic tubes face the following problems during the manufacturing process: 1. During the manufacturing process of ceramic tubes, the gas in the raw materials cannot be completely discharged, and there are often pores in the molds, resulting in pores on the surface or inside of the ceramic tubes. The pores will reduce the strength of the ceramic tubes and thus affect the performance of the ceramic tubes. 2. During the production process of ceramic tubes, stress concentration, layer separation, and uneven cooling during the forming step will cause cracks in the ceramic tubes. The cracks will reduce the strength and toughness of the ceramic tubes.

[0004] Based on the above statements, this application provides a high-strength cordierite-mullite ceramic tube and its preparation process. Summary of the Invention

[0005] To solve the problems raised in the background art, this application provides a high-strength cordierite-mullite ceramic tube and its preparation process.

[0006] In the first aspect, this application provides a high-strength cordierite-mullite ceramic tube, adopting the following technical solution:

[0007] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight: 20-40 parts of mullite, 20-30 parts of cordierite, 12-16 parts of alumina, and 0.4-1 part of sintering aid.

[0008] Preferably, the particle size of the mullite is 1-10 μm, the particle size of the cordierite is 1-3 mm, the alumina is α-alumina, and the particle size is 5-10 μm.

[0009] Preferably, the preparation of the sintering aid is as follows: Add nano-lithium silicate into a boric acid solution with a mass concentration of 10-20%, and perform ultrasonic dispersion to obtain a dispersion liquid. Then add a silane coupling agent into the dispersion liquid and perform ultrasonic dispersion to obtain the sintering aid.

[0010] Preferably, the mass ratio of the nano-lithium cobaltate to the boric acid solution is 1:2-4; the mass ratio of the silane coupling agent to the dispersion liquid is 1:20-30; the silane coupling agent is an epoxy-based silane coupling agent.

[0011] In a second aspect, the present application provides a preparation process for a high-strength cordierite-mullite ceramic tube, adopting the following technical solution:

[0012] A preparation process for a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0013] S1. Mix and stir the raw materials by weight to obtain a mixture;

[0014] S2. Press the mixture in an isostatic pressing device to obtain a green body of the ceramic tube;

[0015] S3. Perform pre-sintering treatment on the green body of the ceramic tube, and naturally cool it to obtain a pre-sintered ceramic tube blank;

[0016] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method, immerse and cure it in a curing solution under vacuum after coating, take it out and dry it to obtain a coated ceramic tube blank;

[0017] S5. Sinter the coated ceramic tube blank in a vacuum high-temperature sintering furnace to obtain a high-strength cordierite-mullite ceramic tube.

[0018] Preferably, the pressing conditions of the isostatic pressing device in step S2 are: the pressure is 150 - 350 Mpa, and the pressing time is 2 - 6 min.

[0019] Preferably, the pre-sintering temperature is 1200 - 1300 °C, and the pre-sintering time is 0.5 - 1 h.

[0020] Preferably, the coating material in step S4 is potassium hexa-titanate whiskers, the particle size is 30 - 50 nm, the vacuum degree of sputtering vacuum coating is 9×10 -7 -11×10 -7 Pa, the sputtering power is 100 - 200 w, and the film thickness is 5 - 10 μm.

[0021] Preferably, the curing solution in step S4 is a polymethylsilane solution with a mass concentration of 10 - 16%, and the curing time is 1 - 2 h.

[0022] Preferably, the sintering conditions in step S5 are: the sintering temperature is 1650 - 1750 °C, and the sintering time is 4 - 6 h.

[0023] In summary, the present application has the following beneficial effects:

[0024] 1. In the present application, nano-lithium silicate is added to boric acid solution and ultrasonically dispersed to obtain a dispersion liquid. Then, a silane coupling agent is added to the dispersion liquid and ultrasonically dispersed to obtain a sintering aid. Boric acid can reduce the sintering temperature of the ceramic, while lithium silicate can enhance the sintering performance of the ceramic. The combined action of the two can enable the ceramic tube to achieve a better sintering effect at a lower temperature.

[0025] 2. In the preparation process of the ceramic tube of the present application, the pre-sintered ceramic is coated on the surface by the sputtering vacuum coating method, and the coating material is potassium hexa-titanate whiskers. The coated ceramic tube is placed in a curing liquid for vacuum infiltration curing, and the curing liquid is a polymethylsilane solution. Both potassium hexa-titanate whiskers and the polymethylsilane cured film have high thermal stability. Their synergistic effect can further enhance the performance stability of the ceramic tube in a high-temperature environment and prevent cracking or deformation caused by thermal stress. The potassium hexa-titanate whisker coating and the polymethylsilane cured film form a composite reinforcement structure on the surface of the ceramic tube, and this composite structure can more effectively absorb and disperse the energy under the action of external forces, thereby improving the overall strength and toughness of the ceramic tube.

[0026] 3. The cordierite-mullite ceramic tube prepared by the present application has the beneficial effects of high stability, high strength, and high toughness. Specific Embodiments

[0027] The following further elaborates on the present application in conjunction with embodiments.

[0028] Embodiments 1-3 provide a high-strength cordierite-mullite ceramic tube and its preparation process.

[0029] Embodiment 1

[0030] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight:

[0031] 20 parts of mullite, 20 parts of cordierite, 12 parts of alumina, 0.4 part of sintering aid.

[0032] Among them, the particle size of mullite is 1 μm, the particle size of cordierite is 1 mm, the alumina is α-alumina, and the particle size is 5 μm.

[0033] The sintering aid is prepared as follows: Add lithium silicate nanometer to a boric acid solution with a mass concentration of 10%, and ultrasonically disperse it at a frequency of 100 kHz for 0.5 h to obtain a dispersion liquid. Then add γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid and ultrasonically disperse it at a frequency of 100 kHz for 0.5 h to obtain the sintering aid. Among them, the mass ratio of lithium cobaltate nanometer to the boric acid solution is 1:2; the mass ratio of γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid is 1:20.

[0034] A preparation process of a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0035] S1. Stir and mix the raw materials at a rate of 80 rpm for 1 h according to the parts by weight to obtain a mixture;

[0036] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 150 Mpa, and the pressing time is 2 min.

[0037] S3. Carry out pre-sintering treatment on the green body of the ceramic tube, and obtain a pre-sintered ceramic tube blank after natural cooling to room temperature. The pre-sintering conditions are as follows: the pre-sintering temperature is 1200 °C, and the pre-sintering time is 0.5 h.

[0038] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method. After coating, place it in a curing solution for vacuum infiltration curing, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The coating material is potassium hexatitanate whiskers with a particle size of 30 nm. The vacuum degree of sputtering vacuum coating is 9×10 -7 Pa, the sputtering power is 100 w, and the film thickness is 5 μm. The curing solution is a polymethylsilane solution with a mass concentration of 10%, and the curing time is 1 h.

[0039] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1650 °C, and the sintering time is 4 h.

[0040] Example 2

[0041] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight:

[0042] 30 parts of mullite, 25 parts of cordierite, 14 parts of alumina, 0.7 part of sintering aid.

[0043] Among them, the particle size of mullite is 5 μm, the particle size of cordierite is 2 mm, the alumina is α-alumina, and the particle size is 8 μm.

[0044] The preparation of the sintering aid is as follows: Add lithium silicate nanometer to a boric acid solution with a mass concentration of 15%, and carry out ultrasonic dispersion at a frequency of 110 kHz for 0.8 h to obtain a dispersion liquid. Add γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid, and carry out ultrasonic dispersion at a frequency of 110 kHz for 0.8 h to obtain the sintering aid. The mass ratio of lithium cobaltate nanometer to the boric acid solution is 1:3; the mass ratio of γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid is 1:25.

[0045] A preparation process of a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0046] S1. Stir and mix the raw materials at a rate of 100 rpm for 2 h according to the parts by weight to obtain a mixture.

[0047] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 250 Mpa and the pressing time is 4 min;

[0048] S3. Perform pre-sintering treatment on the green body of the ceramic tube, and obtain a pre-sintered ceramic tube blank after natural cooling to room temperature. The pre-sintering conditions are as follows: the pre-sintering temperature is 1250 °C and the pre-sintering time is 0.8 h;

[0049] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method, immerse and cure it in a curing solution under vacuum after coating, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The coating material is potassium hexatitanate whiskers with a particle size of 40 nm, the vacuum degree of sputtering vacuum coating is 10×10 -7 , the sputtering power is 150 w, and the film thickness is 8 μm. The curing solution is a polymethylsilane solution with a mass concentration of 13%, and the curing time is 1.5 h;

[0050] S5. Sinter the coated ceramic tube blank in a vacuum high-temperature sintering furnace to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1700 °C and the sintering time is 5 h.

[0051] Example 3

[0052] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight:

[0053] 40 parts of mullite, 30 parts of cordierite, 16 parts of alumina, and 1 part of sintering aid.

[0054] Among them, the particle size of mullite is 10 μm, the particle size of cordierite is 3 mm, the alumina is α-alumina, and the particle size is 10 μm.

[0055] The preparation of the sintering aid is as follows: Add lithium silicate nanometer to a boric acid solution with a mass concentration of 20%, ultrasonically disperse it at a frequency of 120 kHz for 1 h to obtain a dispersion liquid, add γ-glycidoxypropyltriethoxysilane to the dispersion liquid, and ultrasonically disperse it at a frequency of 120 kHz for 1 h to obtain the sintering aid. The mass ratio of lithium cobaltate nanometer to the boric acid solution is 1:4; the mass ratio of γ-glycidoxypropyltriethoxysilane to the dispersion liquid is 1:30.

[0056] A preparation process of a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0057] S1. Stir and mix the raw materials at a rate of 120 rpm for 3 h according to the parts by weight to obtain a mixture;

[0058] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 350 Mpa, and the pressing time is 6 min;

[0059] S3. Perform pre-sintering treatment on the green body of the ceramic tube, and obtain a pre-sintered ceramic tube blank after natural cooling to room temperature. The pre-sintering conditions are as follows: the pre-sintering temperature is 1300 °C, and the pre-sintering time is 1 h;

[0060] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method, place it in a curing solution for vacuum infiltration and curing after coating, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The coating material is potassium hexatitanate whiskers with a particle size of 50 nm, the vacuum degree of sputtering vacuum coating is 11×10 -7 Pa, the sputtering power is 200 w, and the film thickness is 10 μm. The curing solution is a polymethylsilane solution with a mass concentration of 16%, and the curing time is 2 h;

[0061] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1750 °C, and the sintering time is 6 h.

[0062] In order to verify the comprehensive performance of the high-strength cordierite-mullite ceramic tubes prepared in Examples 1-3 of the present application, the applicant set Comparative Examples 1-4, which are specifically as follows:

[0063] Comparative Example 1

[0064] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight:

[0065] 20 parts of mullite, 20 parts of cordierite, 12 parts of alumina, 0.4 part of sintering aid.

[0066] Among them, the particle size of mullite is 1 μm, the particle size of cordierite is 1 mm, the alumina is α-alumina, and the particle size is 5 μm.

[0067] The sintering aid is prepared as follows: Add γ-glycidyl ether oxypropyltriethoxysilane to a boric acid solution with a mass concentration of 10%, and perform ultrasonic dispersion at a frequency of 100 kHz for 0.5 h to obtain the sintering aid. The mass ratio of γ-glycidyl ether oxypropyltriethoxysilane to the boric acid solution is 1:20.

[0068] A preparation process of a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0069] S1. Stir and mix the raw materials at a rate of 80 rpm for 1 h according to the parts by weight to obtain a mixture;

[0070] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 150 Mpa, and the pressing time is 2 min.

[0071] S3. Perform pre-sintering treatment on the green body of the ceramic tube, and naturally cool it to room temperature to obtain a pre-sintered ceramic tube blank. The pre-sintering conditions are as follows: the pre-sintering temperature is 1200 °C, and the pre-sintering time is 0.5 h.

[0072] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method, immerse and cure it in a curing liquid under vacuum after coating, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The coating material is potassium hexatitanate whiskers with a particle size of 30 nm. The vacuum degree of sputtering vacuum coating is 9×10 -7 Pa, the sputtering power is 100 w, and the film thickness is 5 μm. The curing liquid is a polymethylsilane solution with a mass concentration of 10%, and the curing time is 1 h.

[0073] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1650 °C, and the sintering time is 4 h.

[0074] Comparative Example 2

[0075] A high-strength cordierite-mullite ceramic tube, comprising the following raw materials in parts by weight:

[0076] 20 parts of mullite, 20 parts of cordierite, 12 parts of alumina, 0.4 part of sintering aid.

[0077] Among them, the particle size of mullite is 1 μm, the particle size of cordierite is 1 mm, the alumina is α-alumina, and the particle size is 5 μm.

[0078] The preparation of the sintering aid is as follows: Add nano lithium silicate to distilled water, and ultrasonically disperse it at a frequency of 100 kHz for 0.5 h to obtain a dispersion liquid. Add γ-glycidoxypropyltriethoxysilane to the dispersion liquid, and ultrasonically disperse it at a frequency of 100 kHz for 0.5 h to obtain the sintering aid. The mass ratio of nano lithium cobaltate to distilled water is 1:2; the mass ratio of γ-glycidoxypropyltriethoxysilane to the dispersion liquid is 1:20.

[0079] A preparation process of a high-strength cordierite-mullite ceramic tube, comprising the following steps:

[0080] S1. Stir and mix the raw materials at a rate of 80 rpm for 1 h according to the parts by weight to obtain a mixture.

[0081] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 150 Mpa, and the pressing time is 2 min.

[0082] S3. Carry out pre-sintering treatment on the green body of the ceramic tube, and naturally cool it to room temperature to obtain a pre-sintered ceramic tube blank. The pre-sintering conditions are as follows: the pre-sintering temperature is 1200 °C, and the pre-sintering time is 0.5 h.

[0083] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method. After coating, place it in a curing solution for vacuum infiltration curing, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The coating material is potassium hexatitanate whiskers with a particle size of 30 nm. The vacuum degree of sputtering vacuum coating is 9×10 -7 Pa, the sputtering power is 100 w, and the film thickness is 5 μm. The curing solution is a polymethylsilane solution with a mass concentration of 10%, and the curing time is 1 h.

[0084] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1650 °C, and the sintering time is 4 h.

[0085] Comparative Example 3

[0086] A high-strength cordierite-mullite ceramic tube comprises the following raw materials in parts by weight:

[0087] 20 parts of mullite, 20 parts of cordierite, 12 parts of alumina, 0.4 part of sintering aid.

[0088] The particle size of the mullite is 1 μm, the particle size of the cordierite is 1 mm, the alumina is α-alumina with a particle size of 5 μm.

[0089] The sintering aid is prepared as follows: Add lithium silicate nanometer to a boric acid solution with a mass concentration of 10%, and carry out ultrasonic dispersion at a frequency of 100 kHz for 0.5 h to obtain a dispersion liquid. Add γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid, and carry out ultrasonic dispersion at a frequency of 100 kHz for 0.5 h to obtain the sintering aid. The mass ratio of lithium cobaltate nanometer to the boric acid solution is 1:2; the mass ratio of γ-glycidyl ether oxypropyltriethoxysilane to the dispersion liquid is 1:20.

[0090] A preparation process of a high-strength cordierite-mullite ceramic tube comprises the following steps:

[0091] S1. Stir and mix the raw materials at a rate of 80 rpm for 1 h according to the parts by weight to obtain a mixture.

[0092] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 150 Mpa, and the pressing time is 2 min;

[0093] S3. Carry out pre-sintering treatment on the green body of the ceramic tube, and obtain a pre-sintered ceramic tube blank after natural cooling to room temperature. The pre-sintering conditions are as follows: the pre-sintering temperature is 1200 °C, and the pre-sintering time is 0.5 h;

[0094] S4. Place the pre-sintered ceramic tube blank in a curing liquid for vacuum infiltration and curing, take it out and place it in an oven at 50 °C for drying for 6 h to obtain a coated ceramic tube blank. The curing liquid is a polymethylsilane solution with a mass concentration of 10%, and the curing time is 1 h;

[0095] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1650 °C, and the sintering time is 4 h.

[0096] Comparative Example 4

[0097] A high-strength cordierite-mullite ceramic tube comprises the following raw materials in parts by weight:

[0098] 20 parts of mullite, 20 parts of cordierite, 12 parts of alumina, 0.4 part of sintering aid.

[0099] Among them, the particle size of mullite is 1 μm, the particle size of cordierite is 1 mm, the alumina is α-alumina, and the particle size is 5 μm.

[0100] The preparation of the sintering aid is as follows: Add lithium silicate nanometer to a boric acid solution with a mass concentration of 10%, and carry out ultrasonic dispersion at a frequency of 100 kHz for 0.5 h to obtain a dispersion liquid. Add γ-glycidoxypropyltriethoxysilane to the dispersion liquid, and carry out ultrasonic dispersion at a frequency of 100 kHz for 0.5 h to obtain the sintering aid. The mass ratio of lithium cobaltate nanometer to the boric acid solution is 1:2; the mass ratio of γ-glycidoxypropyltriethoxysilane to the dispersion liquid is 1:20.

[0101] A preparation process of a high-strength cordierite-mullite ceramic tube comprises the following steps:

[0102] S1. Stir and mix the raw materials at a rate of 80 rpm for 1 h according to the parts by weight to obtain a mixture;

[0103] S2. Place the mixture in an isostatic pressing equipment for pressing to obtain a green body of the ceramic tube. The pressing conditions of the isostatic pressing equipment are as follows: the pressure is 150 Mpa, and the pressing time is 2 min;

[0104] S3. Subject the green body of the ceramic tube to pre-sintering treatment, and obtain a pre-sintered ceramic tube blank after natural cooling to room temperature. The pre-sintering conditions are as follows: the pre-sintering temperature is 1200 °C, and the pre-sintering time is 0.5 h.

[0105] S4. Coat the surface of the pre-sintered ceramic tube blank by sputtering vacuum coating method to obtain a coated ceramic tube blank. The coating material is potassium hexa-titanate whiskers with a particle size of 30 nm. The vacuum degree of sputtering vacuum coating is 9×10 -7 Pa, the sputtering power is 100 w, and the film thickness is 5 μm.

[0106] S5. Place the coated ceramic tube blank in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube. The sintering conditions are as follows: the sintering temperature is 1650 °C, and the sintering time is 4 h.

[0107] Performance testing

[0108] Test the comprehensive performance of the high-strength cordierite-mullite ceramic tubes prepared in Examples 1-3 and Comparative Examples 1-4 of the present application respectively.

[0109] Test the mechanical strength of the high-strength cordierite-mullite ceramic tubes prepared in Examples 1-3 and Comparative Examples 1-4 in accordance with GB / T 4740-1999. The results are shown in Table 1:

[0110] Table 1

[0111]

[0112] As can be seen from the data shown in Table 1, the comprehensive performance of the high-strength cordierite-mullite ceramic tubes prepared in Examples 1-3 is far superior to that of Comparative Examples 1-4. The high-strength cordierite-mullite ceramic tubes prepared in Examples 1-3 have high flexural strength and high fracture toughness.

[0113] This specific embodiment is only an explanation of the present application, and it does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high-strength cordierite-mullite ceramic tube, characterized in that: The invention comprises the following raw materials in parts by weight: 20-40 parts of mullite, 20-30 parts of cordierite, 12-16 parts of alumina, and 0.4-1 parts of a sintering aid; The sintering aid is prepared as follows: adding nano lithium silicate to a boric acid solution with a mass concentration of 10-20%, ultrasonically dispersing to obtain a dispersion, adding a silane coupling agent to the dispersion, ultrasonically dispersing to obtain a sintering aid; The preparation process of the high-strength cordierite-mullite ceramic tube comprises the following steps: S1, mixing and stirring the raw materials according to weight to obtain a mixture; S2, pressing the mixture in an isostatic pressing device to obtain a ceramic tube green body; S3, pre-sintering the ceramic tube green body, and obtaining a pre-sintered ceramic tube body after natural cooling; S4, coating the surface of the pre-sintered ceramic tube body by a sputtering vacuum coating method, placing the pre-sintered ceramic tube body in a curing liquid for vacuum infiltration and curing after coating, taking it out and drying it to obtain a coated ceramic tube body; S5, placing the coated ceramic tube body in a vacuum high-temperature sintering furnace for sintering to obtain a high-strength cordierite-mullite ceramic tube; The coating material in step S4 is potassium hexatitanate whiskers with a particle size of 30-50 nm, and the vacuum degree of sputtering vacuum coating is 9×10 -7 -11×10 -7 Pa, sputtering power is 100-200w, film thickness is 5-10μm; In step S4, the curing liquid is a polymethylsilane solution with a mass concentration of 10-16%, and the curing time is 1-2 hours.

2. The high-strength cordierite-mullite ceramic tube according to claim 1, characterized in that: The particle size of the mullite is 1-10 μm, the particle size of the cordierite is 1-3 mm, and the alumina is α-alumina with a particle size of 5-10 μm.

3. The high-strength cordierite-mullite ceramic tube according to claim 1, characterized in that: The mass ratio of the nano lithium silicate to the boric acid solution is 1:2-4; the mass ratio of the silane coupling agent to the dispersion is 1:20-30; and the silane coupling agent is an epoxy silane coupling agent.

4. The high-strength cordierite-mullite ceramic tube according to claim 1, characterized in that: The pressing conditions of the medium static pressure equipment in step S2 are: pressure of 150-350 MPa, and pressing time of 2-6 min.

5. The high-strength cordierite-mullite ceramic tube according to claim 1, characterized in that: The pre-sintering conditions in step S3 are as follows: the pre-sintering temperature is 1200-1300° C., and the pre-sintering time is 0.5-1 h.

6. The high-strength cordierite-mullite ceramic tube according to claim 1, characterized in that: The sintering conditions in step S5 are as follows: the sintering temperature is 1650-1750° C., and the sintering time is 4-6 hours.

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