A method for making a composite of a dense palladium membrane and a porous metal material

Abstract

The application discloses a kind of dense palladium membrane and the composite method of porous metal, comprising the following steps: step one, dense palladium membrane is sequentially polished and ultrasonic cleaning, and obtain pretreated dense palladium membrane;Step two, diffusion welding connection: pretreated dense palladium membrane is placed on porous metal material, then it is placed between the upper pressure head and lower pressure head of vacuum diffusion furnace and is treated by vacuum diffusion welding, and the composite of dense palladium membrane and porous metal material is completed.The application is preprocessed to dense palladium membrane, which facilitates the close connection of dense palladium membrane and porous metal material, improves the effective welding area, and ensures the performance of dense palladium membrane and porous metal material after compounding.By placing the pretreated dense palladium membrane on the porous metal material and then performing vacuum diffusion welding treatment, the dense palladium membrane is combined with the porous metal material, which not only saves the amount of precious metal and reduces the product cost, but also greatly improves the hydrogen permeation rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heterogeneous metal composite, and particularly relates to a method for compounding a dense palladium film and a porous metal material. BACKGROUND

[0002] The commonly used palladium or palladium alloy hydrogen permeable material in industry is a palladium or palladium alloy pipe, which is generally prepared by rolling and drawing. In order to maintain sufficient mechanical strength and stability, the film thickness is relatively large (> 80 microns), which not only increases the cost, but also reduces the hydrogen permeation rate of the palladium pipe due to the large wall thickness. In order to reduce the thickness of the palladium film, researchers aim at composite film. That is, a thin palladium film (< 10 microns) is prepared on a porous material as a substrate. By using a palladium composite film, the thickness of the palladium film can be reduced by an order of magnitude, and the hydrogen permeation rate of the film can be increased by at least an order of magnitude.

[0003] In order to reduce the thickness of the palladium alloy while increasing the pressure it can withstand, the palladium film must be attached to a porous support. The support can be a porous ceramic, a porous glass or a porous metal. The preparation of the palladium film support can use chemical plating, chemical vapor deposition, thermal deposition, sputtering, plating and other methods. These methods can well control the composition, thickness and structure of palladium or palladium film. However, the composite palladium film prepared by the above methods is prone to micropores during preparation, and the mechanical and thermal stability of the film is poor, and cracks, shedding and other problems are prone to occur during high temperature use. And due to the difference in expansion coefficient between the palladium film and the porous material, the reliable sealing welding of the composite film is more difficult. This is also a technical difficulty that needs to be solved in the industrial application of porous material palladium composite film.

[0004] Therefore, a method for compounding a dense palladium film and a porous metal material is needed. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for compounding a dense palladium film and a porous metal material to solve the above technical problems of the prior art. The method is to pretreat the dense palladium film to facilitate the close connection between the dense palladium film and the porous metal material, and to ensure the performance of the composite of the dense palladium film and the porous metal material. The pretreated dense palladium film is placed on the porous metal material and then subjected to vacuum diffusion welding treatment to composite the dense palladium film and the porous metal material. The thickness of the palladium film is reduced while the strength of the film is ensured. The use of noble metal is saved, the product cost is reduced, and the hydrogen permeation rate is greatly improved.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a method for compounding a dense palladium film and a porous metal material, characterized in that the method comprises the following steps:

[0007] Step one, pretreatment: polishing and ultrasonic cleaning the dense palladium membrane in sequence to obtain a pretreated dense palladium membrane;

[0008] Step two, diffusion welding connection: placing the pretreated dense palladium membrane obtained in step one on the porous metal material, and then placing it between the upper and lower pressing heads of a vacuum diffusion furnace for vacuum diffusion welding treatment to complete the compounding of the dense palladium membrane and the porous metal material.

[0009] The present application polishes the dense palladium membrane with fine sandpaper to make the surface of the dense palladium membrane flat, and uses acetone to ultrasonically clean the dense palladium membrane to remove surface oil stains and impurities, which facilitates the close connection of the dense palladium membrane and the porous metal material and ensures the performance of the composite of the dense palladium membrane and the porous metal material. The pretreated dense palladium membrane is placed on the porous metal material and then subjected to vacuum diffusion welding treatment, which makes the dense palladium membrane and the porous metal material composite, reduces the thickness of the palladium membrane while ensuring the strength of the membrane, saves the amount of precious metal, reduces product cost, and greatly improves the hydrogen permeation rate.

[0010] The composite method of the dense palladium membrane and the porous metal material has the characteristics that the porous metal material in step two is nickel and its alloy, copper and its alloy, or stainless steel. The present application controls the material of the porous metal material, has the advantages of low price, low processing and manufacturing cost, similar expansion coefficient to the palladium membrane, and not easy to fall off under working conditions.

[0011] The composite method of the dense palladium membrane and the porous metal material has the characteristics that the material of the dense palladium membrane in step one is pure palladium or a palladium alloy, and the palladium alloy includes Pd-Ag alloy, Pd-Cu alloy, Pd-Re alloy, Pd-Y alloy, and PdAgAuNi alloy. The present application is suitable for various dense palladium membranes of palladium or palladium alloy, and forms different composite materials according to different requirements.

[0012] The method for compounding the dense palladium membrane and the porous metal material, characterized in that the thickness of the dense palladium membrane in step one is 0.01mm-0.1mm. The dense palladium membrane adopted in the application is relative to the porous membrane, mainly composed of the crystal region and the amorphous region, with small pore diameter, and the pore structure of the membrane is difficult to be distinguished by electron microscope, and can only be measured by gas permeation method or gas adsorption method, and is usually produced by mechanical rolling method, and the membrane prepared by electroplating, chemical plating and gas deposition is called the porous membrane due to large pore diameter and thin thickness; the thickness of the dense palladium membrane is controlled in the application, so that the denseness of the membrane can be ensured, the use cost is reduced, the membrane material with high hydrogen permeation rate is obtained, the stability of the membrane product is high, the hydrogen permeation rate of the membrane is low when the thickness is greater than 0.1mm, the processing cost is high when the thickness is less than 0.01mm, the denseness of the membrane is difficult to be ensured, and the pinhole and other defects are prone to occur, which affects the selection of the hydrogen permeation performance of the membrane.

[0013] The method for compounding the dense palladium membrane and the porous metal material, characterized in that the process of the vacuum diffusion welding in step two is that the vacuum diffusion furnace is vacuumized to 1.0*10 -2 Pa, then the pressure between the upper pressing head and the lower pressing head is 4MPa-10MPa, the temperature is heated to 600-900℃ at the heating rate of 5-10℃ / min, and then the temperature is kept for 30-60min, the furnace is cooled to below 100℃, the pressure is stopped, and finally the leveling is performed. The gas and impurities in the material are volatilized by vacuumizing, so that the surface and the inside of the material become more pure and uniform, which is beneficial to improve the compounding strength, the pressure between the upper pressing head and the lower pressing head is controlled, that is, the pressure is applied to the pretreated dense palladium membrane and the porous metal material, so that the two materials are slightly plastically deformed at the interface, the contact area of the two materials is increased, and the bonding strength is improved, but the excessive compounding pressure will cause the palladium membrane to be severely twisted and deformed, and even damaged, so the pressure is controlled to be 4MPa-10MPa, so that the best compounding effect is achieved, the heating rate, the heating temperature and the time of the vacuum diffusion welding are controlled to be above the lowest recrystallization temperature of the base alloy and below the liquidus temperature, and the certain heating rate and the holding time can make the materials on both sides of the contact surface to be diffused at the interface and in the body, so that the contact surface is tightly bonded and the compounding strength is improved.

[0014] The method for compounding the dense palladium membrane and the porous metal material, characterized in that the upper pressing head and the lower pressing head in step two are provided with the solder resist layer. The solder resist layer is arranged to prevent the dense palladium membrane and the porous metal material from being welded with the upper pressing head and the lower pressing head.

[0015] The method for compounding the dense palladium film and the porous metal material has the characteristics that in the step two, the intermediate layer material is prepared on the surface of the porous metal material, and the polished surface of the pretreated dense palladium film is connected with the surface of the porous metal material with the intermediate layer material.

[0016] The method for compounding the dense palladium film and the porous metal material has the characteristics that the intermediate layer material is prepared by electroplating, chemical plating, physical vapor deposition or ion sputtering.

[0017] The method for compounding the dense palladium film and the porous metal material has the characteristics that the material of the intermediate layer material is Ni, Cu or Ag, and the thickness of the intermediate layer material is 3-10 microns.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1. The present application can facilitate the close connection between the dense palladium film and the porous metal material by pretreating the dense palladium film, and can ensure the performance of the composite of the dense palladium film and the porous metal material.

[0020] 2. The present application can realize the compounding and welding of the dense palladium film and the porous metal material support by the diffusion welding method without adding the solder, and can effectively control the welding area and the welding strength by pre-plating an intermediate layer material.

[0021] 3、The dense palladium film used in the application is prepared by alloy smelting and mechanical rolling, which can realize the preparation of multi-element and complex component film material, and the film has good compactness and stability, and no defects such as pinholes and pores on the film surface.

[0022] 4、The application realizes the compounding of the dense palladium film and the porous metal material by using pretreatment and diffusion welding connection in sequence, which is simple to operate, convenient to control, low in cost, and convenient for industrialized production, and has good application prospect in the field of high-purity hydrogen purification and separation.

[0023] 5、The thickness of the palladium film is reduced by one order of magnitude by compounding the dense palladium film and the porous metal material, and the hydrogen permeation rate of the film is increased by at least one order of magnitude.

[0024] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structure schematic view when the dense palladium film and the porous metal material of the application are subjected to vacuum diffusion welding treatment.

[0026] Mark explanation:

[0027] 1 - upper pressing head; 2 - upper solder resist layer; 3 - dense palladium film;

[0028] 4 - intermediate layer material; 5 - porous metal material; 6 - lower solder resist layer;

[0029] 7 - lower pressing head. DETAILED DESCRIPTION

[0030] Figure 1 is a structure schematic view when the dense palladium film and the porous metal material of the application are subjected to vacuum diffusion welding treatment. Figure 1 As can be seen from the figure, the upper pressing head 1 is provided with an upper solder resist layer 2 at the lower part, the upper solder resist layer 2 is provided with a dense palladium film 3 below, the dense palladium film 3 is provided with a porous metal material 5 with an intermediate layer material 4 at the lower part, and the intermediate layer material 4 is in contact with the dense palladium film 3, the porous metal material 5 is provided with a lower solder resist layer 6 below, and the lower solder resist layer 6 is provided with a lower pressing head 7 at the lower part.

[0031] Example 1

[0032] This example includes the following steps:

[0033] Step one, pretreatment: a Cu intermediate layer material with a thickness of 5 μm is prepared on the surface of a Ni68Cu28Fe porous metal material with a thickness of 0.1 mm by electroplating, a PdCu40 dense palladium film with a thickness of 0.015 mm is gently polished with a fine sandpaper from No. 200 to No. 1000, then the porous metal material and the dense palladium film are ultrasonically cleaned in acetone for 10 min to remove surface oil stains and impurities, and then dried with cold air to obtain a pretreated porous metal material and a pretreated dense palladium film;

[0034] Step two, diffusion welding connection: the pretreated dense palladium film obtained in step one is placed on the pretreated porous metal material obtained in step one, and then placed between the upper and lower pressing heads of a vacuum diffusion furnace for vacuum diffusion welding treatment to complete the compounding of the dense palladium film and the porous metal material; the process of the vacuum diffusion welding treatment is as follows: the vacuum diffusion furnace is evacuated to 5.0 x 10 -3 Pa, then the pressure between the upper and lower pressing heads is 5 MPa, and heated to 800℃ at a heating rate of 10℃ / min and kept for 30 min, then cooled to below 100℃ with the furnace and stopped pressing, and finally leveled; the upper and lower pressing heads are provided with a solder resist layer; the polished surface of the pretreated dense palladium film is connected with the side of the porous metal material having the intermediate layer material.

[0035] The intermediate layer material of the embodiment can also be prepared by chemical plating, physical vapor deposition or ion sputtering.

[0036] Example 2

[0037] The embodiment includes the following steps:

[0038] Step one, pretreatment: a Ni intermediate layer material with a thickness of 3 μm is prepared on the surface of a 1Cr18Ni9Ti stainless steel porous metal material with a thickness of 0.15 mm by electroplating, a PdAgAuNi23-3-0.3 dense palladium film with a thickness of 0.02 mm is gently polished with a fine sandpaper from No. 200 to No. 1000, then the porous metal material and the dense palladium film are ultrasonically cleaned in acetone for 10 min to remove surface oil stains and impurities, and then dried with cold air to obtain a pretreated porous metal material and a pretreated dense palladium film;

[0039] Step two, diffusion welding connection: the pretreated dense palladium film obtained in step one is placed on the pretreated porous metal material obtained in step one, and then placed between the upper and lower pressing heads of a vacuum diffusion furnace for vacuum diffusion welding treatment to complete the compounding of the dense palladium film and the porous metal material; the process of the vacuum diffusion welding treatment is as follows: the vacuum diffusion furnace is evacuated to 2.0 x 10 -2Pa, then the pressure between the upper and lower press head is 4 MPa, and heated to 600 ℃ at a rate of 5 ℃ / min, and then kept for 20 min, and then cooled to below 100 ℃ with the furnace, and then stop pressing, and finally leveling; the upper and lower press head is provided with a solder resist layer; the polished surface of the pretreated dense palladium film is connected with the side of the porous metal material having the intermediate layer material.

[0040] The intermediate layer material of the embodiment can also be prepared by electroless plating, physical vapor deposition or ion sputtering.

[0041] Example 3

[0042] The embodiment includes the following steps:

[0043] Step one, pretreatment: an Ag intermediate layer material with a thickness of 4 μm is prepared on the surface of a CuNi30 porous metal material with a thickness of 0.2 mm by electroplating, and a PdY dense palladium film with a thickness of 0.025 mm is gently polished with a fine sandpaper with a number of 200-1000, and then the porous metal material and the dense palladium film are ultrasonically cleaned in acetone for 10 min to remove surface oil and impurities, and then dried with cold air to obtain a pretreated porous metal material and a pretreated dense palladium film;

[0044] Step two, diffusion welding connection: the pretreated dense palladium film obtained in step one is placed on the pretreated porous metal material obtained in step one, and then placed between the upper and lower press head of a vacuum diffusion furnace for vacuum diffusion welding treatment to complete the compounding of the dense palladium film and the porous metal material; the process of the vacuum diffusion welding treatment is as follows: the vacuum diffusion furnace is evacuated to 3.0×10 -3 Pa, then the pressure between the upper and lower press head is 4 MPa, and heated to 600 ℃ at a rate of 5 ℃ / min, and then kept for 20 min, and then cooled to below 100 ℃ with the furnace, and then stop pressing, and finally leveling; the upper and lower press head is provided with a solder resist layer; the polished surface of the pretreated dense palladium film is connected with the side of the porous metal material having the intermediate layer material.

[0045] The intermediate layer material of the embodiment can also be prepared by electroless plating, physical vapor deposition or ion sputtering.

[0046] Example 4

[0047] The difference between the embodiment and example 3 is that no intermediate layer material is electroplated on the surface of a CuNi30 porous metal material with a thickness of 0.2 mm.

[0048] Example 5

[0049] The difference between the embodiment and example 3 is that the dense palladium film is a Pd-Re alloy.

[0050] Example 6

[0051] The difference between this example and Example 3 is that the porous metal material is nickel.

[0052] Example 7

[0053] The difference between this example and Example 3 is that the porous metal material is copper.

[0054] The above merely describes the preferred embodiments of the present application, but does not in any way limit the present application. Any simple modification, change, and equivalent variation of the above embodiments according to the technical essence of the present application are still within the protection scope of the technical solutions of the present application.

Claims

1. A composite method of a dense palladium membrane and a porous metal material, characterized in that: The method comprises the following steps: Step 1, pretreatment: polishing and ultrasonic cleaning the dense palladium film in sequence to obtain a pretreated dense palladium film; the thickness of the dense palladium film is 0.01 mm to 0.1 mm; Step 2, diffusion welding connection: Place the pretreated dense palladium film obtained in step 1 on the porous metal material, and then put it between the upper pressure head and the lower pressure head of the vacuum diffusion furnace for vacuum diffusion welding treatment to complete the composite of the dense palladium film and the porous metal material; the upper pressure head and the lower pressure head are provided with a solder resist layer; an intermediate layer material is prepared on the surface of the porous metal material, and the polished surface of the pretreated dense palladium film is connected to the side of the porous metal material having the intermediate layer material.

2. The composite method of a dense palladium membrane and a porous metal material according to claim 1, characterized in that: The porous metal material in step 2 is nickel and its alloys, copper and its alloys or stainless steel.

3. The composite method of a dense palladium membrane and a porous metal material according to claim 1, characterized in that: The material of the dense palladium film in step 1 is: pure palladium or palladium alloy with a mass purity of not less than 99%, and the palladium alloy includes Pd-Ag alloy, Pd-Cu alloy, Pd-Re alloy, Pd-Y alloy, and PdAgAuNi alloy.

4. The composite method of a dense palladium membrane and a porous metal material according to claim 1, characterized in that: The process of vacuum diffusion welding in step 2 is as follows: evacuate the vacuum diffusion furnace to a vacuum of 1.0×10 -2 Pa, then make the pressure between the upper and lower pressure heads 4MPa~10MPa, and heat to 600℃~900℃ at a heating rate of 5℃ / min~10℃ / min, then keep warm for 30min~60min, and then stop applying pressure after cooling to below 100℃ with the furnace, and finally level it.

5. The composite method of a dense palladium membrane and a porous metal material according to claim 1, characterized in that: The intermediate layer material is prepared by electroplating, chemical plating, physical vapor deposition or ion sputtering.

6. The composite method of a dense palladium membrane and a porous metal material according to claim 1, characterized in that: The material of the intermediate layer is Ni, Cu or Ag, and the thickness of the intermediate layer is 3 μm to 10 μm.

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