Connecting process of metal ceramic membrane assembly

Abstract

The invention provides a connecting process of a metal ceramic membrane component, which comprises the following steps: uniformly coating the outer surface of a porous ceramic tube with a coating liquid prepared from ceramic powder and metal powder to obtain a porous ceramic tube with a metal ceramic coating; putting the porous ceramic tube into a mold, forming a plugging clamping groove in one end of the mold, forming a cavity among the outer wall of the porous ceramic tube, the plugging clamping groove and the mold, filling metal powder into the cavity, and arranging a plugging fixing piece at the other end of the mold, and finally, the obtained metal ceramic assembly blank is subjected to high-temperature sintering, and the metal ceramic membrane assembly can be prepared. According to the invention, effective combination of the metal film layer and the ceramic film layer is realized through a co-firing technology by utilizing a mold forming and surface modification process. The prepared metal ceramic membrane assembly can be directly connected with a device in a welded mode in the using process, the membrane layer precision is high, the thermal shock resistance is good, and the metal ceramic membrane assembly is suitable for high-temperature, high-pressure, high-viscosity and other severe systems in the petrochemical industry field.

Description

Technical Field

[0001] This invention belongs to the field of membrane material and membrane module preparation technology, specifically relating to a connection process for a metal-ceramic membrane module. Background Technology

[0002] In existing industrial production, the performance requirements for materials are constantly increasing, and the properties of single-material components can no longer meet industrial production needs. Therefore, the creation of composite materials with novel properties from two or more materials with different properties through physical or chemical methods has become a research hotspot in the materials science field. Currently, structural components used in industrial production involve the connection of ceramic and metallic materials. Metal-ceramic composite materials, also a type of non-metal-metal composite material, possess the advantages of both metallic and ceramic materials, making them a promising composite material with broad application prospects in fields such as medicine, automobiles, aviation, and aerospace. However, the chemical bond structures of metallic and ceramic materials are completely different, resulting in poor wettability between them, making chemical bonding difficult. Therefore, existing technologies typically employ mechanical connections. However, mechanical connections increase structural weight and result in low bond strength, leading to performance far below expectations for these composite materials. Furthermore, they are prone to separation during use, severely hindering their large-scale application.

[0003] To improve existing techniques for joining metallic and ceramic materials, researchers in this field are constantly updating and refining the technology. Patent CN1528714A provides a method for joining carbon, ceramic non-metallic materials, and metallic materials. First, the ceramic or composite material undergoes surface treatment including degreasing, activation, sensitization, and pre-plating. Then, a chemical nickel or copper plating process is used to metallize the ceramic or composite surface. Afterward, it is placed in an electroforming electrolyte for 20–40 hours of electroforming. Finally, the electroformed plating layer is slightly processed and directly welded or threaded to the metal part. This method offers high weld strength, but the process is relatively complex and time-consuming. Patent CN105384457A discloses a method for welding alumina ceramics to molybdenum. The method involves first pre-treating the required alumina ceramic rod, molybdenum column, and molybdenum sheet; then inserting the pre-treated alumina ceramic rod into a groove on the pre-treated molybdenum column; finally, placing the molybdenum sheet on the side of the molybdenum column where the alumina ceramic rod is inserted, ensuring the alumina ceramic rod penetrates through a through-hole in the molybdenum sheet; adding an adhesive at the junction of the alumina ceramic rod, molybdenum column, and molybdenum sheet to obtain the workpiece; and finally, placing the workpiece in a vacuum furnace for heat treatment to obtain the final product. This method does not require metallization of the ceramic and is simple and easy to operate. However, it requires the use of organic solvents for pre-treatment of the alumina ceramic rod, molybdenum column, and molybdenum sheet, which may be harmful to human health and the environment. Furthermore, the method involves a high sintering temperature and high cost. Patent 109708783A provides a corrosion-resistant metal thin film assembly and its laser welding method. The method uses a diaphragm and gasket made of corrosion-resistant material. The gasket is welded to the body as a whole, which solves the problem of high cost of corrosion-resistant material and improves the welding qualification rate of parts. However, weld seams are prone to occur during welding, requiring surface shaping and airtightness testing, which increases manufacturing costs.

[0004] In view of the above problems, simplifying the preparation process, reducing production costs, and improving the connection strength between metal and ceramic materials are the research focus of researchers. Summary of the Invention

[0005] This invention aims to provide a simple process for preparing metal-ceramic membrane modules with high bonding strength between the metal and ceramic materials. This process employs in-situ co-firing, is simple to operate, low in cost, and yields metal membrane modules with high performance, which is beneficial for the large-scale application of metal-ceramic membrane modules.

[0006] The specific idea of ​​this invention is as follows: First, a coating liquid prepared from ceramic powder and metal powder is uniformly coated on the outer surface of a porous ceramic tube to obtain a porous ceramic tube with a metal-ceramic coating. This tube is then placed in a mold, and a sealing groove is provided at one end of the mold, forming a cavity between the outer wall of the porous ceramic tube, the sealing groove, and the mold. Metal powder is then filled into the cavity, while a sealing and fixing component is provided at the other end of the mold. Finally, the resulting metal-ceramic assembly preform is sintered at high temperature to prepare a metal-ceramic membrane module. This invention utilizes mold forming and surface modification processes to achieve effective connection between the metal membrane and the ceramic membrane module, resulting in a metal-ceramic membrane module with high porosity and uniform pore size. By coating the outer surface of the porous ceramic tube with a metal-ceramic coating, this invention achieves two benefits: firstly, the metal-ceramic coating can modify the porous ceramic tube and improve its performance; secondly, the metal powder added to the coating liquid can effectively reduce the coefficient of thermal expansion between the metal and ceramic materials; and thirdly, the high-temperature sintering and melting of the metal powder allows for effective bonding between the porous ceramic tube and the metal powder added to the cavity. The mold forming process used in this invention is beneficial for the positioning and sintering of metal powder and porous ceramic tube, resulting in a uniform film layer and high repeatability.

[0007] This invention features a simple process, high yield, and effective bonding of metal and ceramic membrane layers through co-firing technology. The resulting metal-ceramic membrane module can be directly welded to the equipment during use, exhibiting high membrane precision and excellent thermal shock resistance, making it perfectly suited for separation processes in harsh systems such as high temperature, high pressure, and high viscosity in the petrochemical industry.

[0008] The technical solution of this invention is:

[0009] 1. A connection process for a metal-ceramic membrane module, characterized in that the process includes the following steps:

[0010] Step 1: Prepare a coating liquid by mixing ceramic powder, metal powder and additives in a certain proportion, and uniformly coat the coating liquid on the outer surface of the porous ceramic tube to obtain a porous ceramic tube with a metal ceramic coating.

[0011] Step 2: Place the porous ceramic tube with metal ceramic coating prepared in Step 1 into a mold, and set a sealing groove at one end of the mold. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove and the mold, to obtain a metal ceramic component preform with a cavity.

[0012] Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with metal powder, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic assembly preform;

[0013] Step 4: The metal-ceramic assembly blank obtained in Step 3 is subjected to high-temperature heat treatment to prepare the metal-ceramic membrane module.

[0014] Specifically, the ceramic powder mentioned in step 1 is alumina, zirconium oxide, titanium oxide, or silicon dioxide; the metal powder is titanium, nickel, or stainless steel; the average particle size of the ceramic powder is 0.01–5 μm; and the average particle size of the metal powder is 0.1–5 μm.

[0015] Specifically, the mass ratio of metal powder, ceramic powder, and additives in step 1 is 1–3:1:10–30. The additives are 3%–10% PVA (polyvinyl alcohol) aqueous solution or methylcellulose aqueous solution, and the thickness of the metal-ceramic film is 1–100 μm. In this invention, the thickness of the metal-ceramic film refers to the thickness of the metal-ceramic coating applied to the outer surface of the porous ceramic tube after sintering.

[0016] Specifically, the thickness of the metal film layer is 0.15 to 5 mm. The thickness of the metal film layer mentioned in this invention refers to the thickness of the metal powder between the porous ceramic tube and the porous metal tube after sintering, excluding the thickness of the porous metal tube.

[0017] Specifically, the average pore size of the porous ceramic tube mentioned in step 1 is 0.1 to 10 μm.

[0018] Specifically, the inner diameter of the mold mentioned in step 2 is 10-100mm and the wall thickness is 1-5mm; the mold material is a porous metal tube with a detachable rigid outer membrane wrapped around its outer wall.

[0019] Specifically, the porous metal tube described in claims 1 and 4 is a titanium metal tube, a stainless steel metal tube, or a nickel metal tube, and the average pore diameter of the porous metal tube is 0.5–5 mm. The porous metal tube is made of the same material as the metal powder, which facilitates the bonding and connection of the metal powder during high-temperature sintering. The detachable rigid outer membrane is a quartz tube or metal mesh with a thickness of 1–10 mm, which can play a positioning role in the molding of the metal-ceramic membrane assembly and prevent small-particle-size metal powder from leaking out of the porous metal tube; the mesh size of the metal mesh is 100–1000 mesh.

[0020] Specifically, the sealing slot mentioned in step 2 is made of metal or ceramic.

[0021] Specifically, the metal powder mentioned in step 3 is stainless steel, titanium, or nickel powder; the average particle size of the metal powder is 1–20 μm. The average pore size of the porous metal tube is 0.5–5 mm, allowing the smaller-sized metal powder filling the cavity to enter the pores of the porous metal tube, achieving diffusion sintering of the metal during high-temperature sintering.

[0022] Specifically, the heat treatment conditions described in step 4 are sintering at 900–1300°C under vacuum, reducing, and inert atmosphere conditions, and holding at that temperature for 1–3 hours.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention involves coating a metal-ceramic coating on the outer surface of a porous ceramic tube. On the one hand, the metal-ceramic coating can modify the porous ceramic tube and improve its performance. On the other hand, the metal powder added to the coating liquid can effectively reduce the coefficient of thermal expansion between the metal and ceramic materials. At the same time, the metal powder can be effectively bonded between the porous ceramic tube, the metal powder added to the cavity, and the porous metal tube mold when the metal powder is sintered and melted at high temperature.

[0025] 2. This invention utilizes a mold-forming process to co-fire a porous ceramic tube with a metal-ceramic coating, metal powder, and a porous metal tube with a detachable outer membrane. The detachable outer membrane effectively prevents small-particle metal powder from leaking out of the porous metal tube and provides positioning for the metal-ceramic membrane assembly. After sintering, it can be removed for convenient reuse. This invention achieves effective connection between the metal and ceramic membranes, resulting in a metal-ceramic membrane assembly with high porosity and good thermal shock resistance, which can be directly welded for use.

[0026] 3. In this invention, the metal powder and the porous metal tube mold are made of the same material. During high-temperature sintering, the metal powder melts, diffuses, and bonds together, which is beneficial to the formation of the metal film.

[0027] 4. The present invention has a simple process and achieves the connection of metal-ceramic membrane modules by co-firing metal and ceramic membrane layers, resulting in membrane modules with high strength and high yield. Attached Figure Description

[0028] Figure 1 This is a pore size distribution diagram of the metal-ceramic membrane module in Example 1.

[0029] Figure 2 This is a cross-sectional SEM image of the metal-ceramic membrane module in Example 1. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in this industry.

[0031] Example 1

[0032] Step 1: Mix 10g of alumina ceramic powder with an average particle size of 0.01μm, 10g of titanium metal powder with an average particle size of 0.1μm, and 300g of 10% PVA aqueous solution in a certain proportion to prepare a coating liquid. Coat the outer surface of the porous ceramic tube with an average pore size of 0.1μm with the coating liquid to obtain a porous ceramic tube with a metal ceramic coating.

[0033] Step 2: Place the porous ceramic tube with metal-ceramic coating prepared in Step 1 into a titanium metal tube with an inner diameter of 10 mm, a thickness of 1 mm, and an average pore size of 0.5 mm (the outer wall is wrapped with a detachable metal mesh with a mesh size of 1000). A sealing groove is set at one end of the titanium metal tube. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove, and the titanium metal tube, resulting in a metal-ceramic component preform with a cavity.

[0034] Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with titanium metal powder with an average particle size of 1μm, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic component preform;

[0035] Step 4: Sinter the metal-ceramic assembly preform obtained in Step 3 at 900℃ under vacuum atmosphere and hold for 3 hours to prepare the metal-ceramic membrane module. The metal-ceramic coating forms a metal-ceramic film (thickness 0.15μm, average pore size 0.03μm), and the metal powder forms a metal film (thickness 0.15mm).

[0036] Example 2

[0037] Step 1: Mix 3g of zirconia ceramic powder with an average particle size of 0.5μm, 10g of stainless steel metal powder with an average particle size of 1μm and 100g of 3% PVA in a certain proportion to prepare a coating liquid. Coat the coating liquid evenly on the outer surface of a porous ceramic tube with an average pore size of 5μm to obtain a porous ceramic tube with a metal ceramic coating.

[0038] Step 2: Place the porous ceramic tube with metal-ceramic coating prepared in Step 1 into a stainless steel metal tube with an inner diameter of 100 mm, a thickness of 5 mm, and an average pore diameter of 1 mm (the outer wall is wrapped with a detachable quartz tube with a thickness of 5 mm). A sealing groove is set at one end of the stainless steel metal tube. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove, and the stainless steel metal tube, resulting in a metal-ceramic component preform with a cavity.

[0039] Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with stainless steel metal powder with an average particle size of 5μm, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic assembly preform;

[0040] Step 4: Sinter the metal-ceramic assembly preform obtained in Step 3 at 1000℃ under vacuum atmosphere and hold for 2.5h to prepare the metal-ceramic membrane module. The metal-ceramic coating forms a metal-ceramic film (100μm thick, 0.2μm average pore size), and the metal powder forms a metal film (5mm thick).

[0041] Example 3

[0042] Step 1: Prepare a coating solution by mixing 5g of titanium dioxide ceramic powder with an average particle size of 5μm, 10g of nickel metal powder with an average particle size of 5μm and 200g of 5% methylcellulose aqueous solution in a certain proportion. Apply the coating solution evenly to the outer surface of a porous ceramic tube with an average pore size of 10μm to obtain a porous ceramic tube with a metal ceramic coating.

[0043] Step 2: Place the porous ceramic tube with metal-ceramic coating prepared in Step 1 into a nickel metal tube with an inner diameter of 50 mm, a thickness of 3 mm, and an average pore size of 5 mm (the outer wall is wrapped with a removable metal mesh with a mesh size of 100). A sealing groove is set at one end of the nickel metal tube. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove, and the nickel metal tube, resulting in a metal-ceramic component preform with a cavity.

[0044] Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with nickel metal powder with an average particle size of 20 μm, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic assembly preform;

[0045] Step 4: The metal-ceramic assembly preform obtained in Step 3 is sintered at 1300℃ under vacuum atmosphere and held for 1 hour to prepare the metal-ceramic membrane module. The metal-ceramic coating forms a metal-ceramic film (thickness 20μm, average pore size 0.8μm), and the metal powder forms a metal film (thickness 2.5mm).

[0046] Example 4

[0047] Step 1: Mix 10g of silica ceramic powder with an average particle size of 2μm, 20g of stainless steel metal powder with an average particle size of 2μm and 150g of 3% methylcellulose aqueous solution in a certain proportion to prepare a coating liquid. Coat the coating liquid uniformly on the outer surface of a porous ceramic tube with an average pore size of 8μm to obtain a porous ceramic tube with a metal ceramic coating.

[0048] Step 2: Place the porous ceramic tube with metal-ceramic coating prepared in Step 1 into a stainless steel metal tube (with an inner diameter of 20 mm, a thickness of 2 mm, and an average pore diameter of 4 mm, and the outer wall is wrapped with a detachable quartz tube with a thickness of 1 mm) and set a sealing groove at one end of the stainless steel metal tube. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove and the stainless steel metal tube to obtain a metal-ceramic component preform with a cavity.

[0049] Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with stainless steel metal powder with an average particle size of 10 μm, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic assembly preform;

[0050] Step 4: Sinter the metal-ceramic assembly preform obtained in Step 3 at 1200℃ under vacuum atmosphere and hold for 1.5h to prepare the metal-ceramic membrane module. The metal-ceramic coating forms a metal-ceramic film (thickness 30μm, average pore size 0.51μm), and the metal powder forms a metal film (thickness 1.5mm).

[0051] Comparative Example

[0052] Comparative Example 1

[0053] This comparative example provides a connection process for a metal-ceramic membrane module, which is basically the same as that in Example 1, except that: in step 1, no metal powder is added. Since no metal powder is added to the coating liquid, cracks are likely to occur between the ceramic material and the metal powder due to the difference in their coefficients of thermal expansion.

[0054] Comparative Example 2

[0055] This comparative example provides a connection process for a metal-ceramic membrane assembly, which is basically the same as that in Example 1, except that in step 2, the outer wall of the porous metal tube is not wrapped with a removable outer membrane, and the metal powder filled in the cavity will leak out from the porous metal tube during the preparation process, thus making it impossible to complete the preparation of the composite membrane.

[0056] The pore size of the samples from Examples 1-4 and Comparative Examples 1-2 was tested using a pore size analyzer based on the bubble point method, the porosity was tested using the Archimedes principle method, and the thermal shock resistance was tested.

[0057] The specific testing method is as follows:

[0058] (1) A pore size analyzer for measuring pore size using the bubble point method

[0059] The pore size is tested using a bubble point method pore size analyzer: The metal membrane tube sample is thoroughly wetted with a wetting agent. One end of the sample is placed in a sealed PVC tube, and the other end is placed in the mold port of the pore size analyzer. The test gas cylinder (nitrogen) is opened, and the upper limit of the test pressure is set to 80 kPa. As the test pressure increases, the pore size decreases, and the wetting agent in the pores is pushed out in sequence, allowing the gas to pass through, until all the pores are opened, achieving the same permeability as the dry membrane. The test results are recorded based on the instrument analysis.

[0060] (2) Archimedes' principle method for testing porosity

[0061] Porosity is tested using Archimedes' principle (water displacement method): the porosity is determined based on the change in weight of the sample before and after being wetted with alcohol. The calculation formula is as follows:

[0062] (Where: p is porosity / %, m0 is the original weight of the sample, m1 is the suspended weight of the sample in the liquid, and m2 is the wet weight of the sample)

[0063] (3) Thermal shock resistance test

[0064] The sample was heated to 500 degrees Celsius and held at that temperature for 30 minutes. Then it was rapidly cooled in cold water. After several cycles, the sample surface was observed to see if cracks or fractures appeared.

[0065] The data obtained after testing the samples from Examples 1-4 and Comparative Examples 1-2 are as follows:

[0066] serial number Average pore size / μm Porosity / % Thermal shock resistance Example 1 0.03 50 No cracks Example 2 0.2 61 No cracks Example 3 0.8 66 No cracks Example 4 0.51 63 No cracks Comparative Example 1 0.03 50 The ceramic film cracked after 3 cycles. Comparative Example 2 none none none

[0067] Comparing Examples 1-4 with Comparative Example 1, we can see that in Comparative Example 1, since no metal powder was added to the coating liquid, cracks are more likely to occur between the ceramic material and the metal powder due to the difference in their coefficients of thermal expansion.

[0068] Comparing Examples 1-4 with Comparative Example 2, we can see that in Comparative Example 2, since the outer wall of the porous metal tube is not wrapped with a removable outer membrane, the metal powder filled in the cavity will leak out from the porous metal tube during the preparation process, thus the composite membrane cannot be prepared.

[0069] As can be seen from the results of the above embodiments and comparative tests:

[0070] 1. This invention involves adding metal powder to a coating liquid and applying the metal-ceramic coating liquid to the outer surface of a porous ceramic tube. On the one hand, the metal-ceramic coating can modify the porous ceramic tube and improve its performance; on the other hand, the metal powder added to the coating liquid can effectively reduce the coefficient of thermal expansion between the metal and ceramic materials; at the same time, the metal powder can be effectively bonded between the porous ceramic tube, the metal powder added to the cavity, and the porous metal tube mold when the metal powder is sintered and melted at high temperature.

[0071] 2. This invention involves co-firing a porous ceramic tube with a metal-ceramic coating, metal powder, and a porous metal tube with a removable outer membrane to prepare a metal-ceramic membrane assembly. The removable outer membrane on the outside of the porous metal tube effectively prevents small-particle metal powder from leaking out, plays a positioning role in the molding of the metal-ceramic membrane assembly, and can be removed after sintering for convenient reuse.

[0072] 3. This invention can achieve effective connection between metal membrane and ceramic membrane, and the prepared metal-ceramic membrane module has high porosity and good thermal shock resistance, and can be directly welded for use.

Claims

1. A connection process for a metal-ceramic membrane module, characterized in that, The process includes the following steps: Step 1: Prepare a coating liquid by mixing ceramic powder, metal powder and additives in a certain proportion, and uniformly coat the coating liquid on the outer surface of the porous ceramic tube to obtain a porous ceramic tube with a metal ceramic coating. Step 2: Place the porous ceramic tube with metal ceramic coating prepared in Step 1 into a mold, and set a sealing groove at one end of the mold. A cavity is formed between the outer wall of the porous ceramic tube, the sealing groove and the mold, to obtain a metal ceramic component preform with a cavity. Step 3: Fill the cavity of the metal-ceramic component preform with cavity prepared in Step 2 with metal powder, and set a sealing and fixing component at the other end of the mold to obtain the metal-ceramic assembly preform; Step 4: The metal-ceramic assembly blank obtained in Step 3 is subjected to high-temperature heat treatment to prepare the metal-ceramic membrane module.

2. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The ceramic powder mentioned in step 1 is alumina, zirconium oxide, titanium oxide, or silicon dioxide; the metal powder is titanium, nickel, or stainless steel; the average particle size of the ceramic powder is 0.01–5 μm; and the average particle size of the metal powder is 0.1–5 μm.

3. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The mass ratio of the metal powder, ceramic powder, and additives mentioned in step 1 is 1-3:1:10-30.

4. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The average pore size of the porous ceramic tube mentioned in step 1 is 0.1–10 μm.

5. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The mold described in step 2 has an inner diameter of 10-100 mm and a wall thickness of 1-5 mm; the mold is a porous metal tube with a detachable rigid outer membrane wrapped around its outer wall.

6. The porous metal tube according to claims 1 and 4 is a titanium metal tube, a stainless steel metal tube, or a nickel metal tube, wherein the average pore diameter of the porous metal tube is 0.5 to 5 mm; and the detachable rigid outer membrane is a quartz tube or a metal mesh.

7. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The sealing slot mentioned in step 2 is made of metal or ceramic.

8. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The metal powder mentioned in step 3 is stainless steel, titanium alloy, or nickel alloy powder; the average particle size of the metal powder is 1-20 μm.

9. The connection process of a metal-ceramic membrane module according to claim 1, characterized in that, The heat treatment conditions described in step 4 are sintering at 900–1300°C under vacuum, reducing, and inert atmosphere conditions, and holding at that temperature for 1–3 hours.

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