阅读说明：本技术 一种钯基合金薄膜和多孔不锈钢载体的连接方法 (Method for connecting palladium-based alloy film and porous stainless steel carrier ) 是由 樊科社 孙昊 董运涛 朱磊 王虎年 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种钯基合金薄膜和多孔不锈钢载体的连接方法,包括以下步骤：一、将硅酸铝纤维纸进行烧结,得到传压材料；二、将传压材料和多孔不锈钢载体置于两层石英玻璃之间进行压型处理,得到组合体；三、在组合体的多孔不锈钢载体上表面覆盖钯基合金薄膜,得到组装体；四、将组装体放置在真空热压烧结炉内进行真空扩散焊处理；五、在蠕变成形装置内校平,得到钯复合膜。本发明通过采用具有弹性变形能力的传压材料,有效减小了超薄的钯基合金薄膜与多孔不锈钢载体之间的空隙,提高了真空扩散焊过程中压力的均匀程度,有效提高了钯合金膜和多孔不锈钢载体的结合率,使制备的钯复合膜的组织均匀性更好,致密度更高,适用于钯复合膜的批量生产。(The invention discloses a method for connecting a palladium-based alloy film and a porous stainless steel carrier, which comprises the following steps: firstly, sintering aluminum silicate fiber paper to obtain a pressure transmission material; secondly, placing the pressure transmission material and the porous stainless steel carrier between two layers of quartz glass for compression treatment to obtain a combined body; thirdly, covering a palladium-based alloy film on the upper surface of the porous stainless steel carrier of the assembly to obtain an assembly; fourthly, placing the assembly in a vacuum hot-pressing sintering furnace for vacuum diffusion welding treatment; and fifthly, leveling in a creep forming device to obtain the palladium composite membrane. According to the invention, by adopting the pressure transmission material with elastic deformation capacity, the gap between the ultrathin palladium-based alloy film and the porous stainless steel carrier is effectively reduced, the uniformity of pressure in the vacuum diffusion welding process is improved, the bonding rate of the palladium alloy film and the porous stainless steel carrier is effectively improved, the tissue uniformity of the prepared palladium composite film is better, the compactness is higher, and the method is suitable for batch production of the palladium composite film.)

1. A method for connecting a palladium-based alloy film and a porous stainless steel carrier is characterized by comprising the following steps:

step one, preparing a pressure transmission material: selecting aluminum silicate fiber paper and sintering to obtain a pressure transmission material;

step two, profiling: placing the pressure transmission material obtained in the step one on the upper surface of quartz glass, then placing a porous stainless steel carrier on the upper surface of the pressure transmission material, covering a layer of quartz glass on the upper surface of the pressure transmission material, and finally placing the pressure transmission material on a hydraulic machine for compression treatment to obtain a combined body, wherein the pressure intensity of the compression treatment is 0.02-0.04 MPa, and the pressure maintaining time is 40-60 min;

step three, assembling: removing the upper quartz glass layer of the combined body obtained in the second step, covering a palladium-based alloy film on the upper surface of the porous stainless steel carrier, and covering the upper quartz glass layer on the upper surface of the palladium-based alloy film to obtain an assembled body, wherein the surface area of the porous stainless steel carrier is larger than that of the palladium-based alloy film;

step four, connection: and (3) placing the assembly obtained in the third step in a vacuum hot-pressing sintering furnace for vacuum diffusion welding treatment, wherein the specific process comprises the following steps: the vacuum degree in the vacuum hot-pressing sintering furnace is increased to 1.0 multiplied by 10^-3Pa is aboveThen, after the temperature in the furnace is raised to 780-820 ℃, starting a hydraulic system, keeping the temperature and pressure for 90-120 min when the pressure born by the assembly is 0.2-0.5 MPa, connecting the palladium-based alloy film with a porous stainless steel carrier, and removing the quartz glass and the pressure transfer material to obtain a palladium composite film semi-finished product;

step five, leveling: and (4) placing the semi-finished product of the palladium composite membrane obtained in the fourth step into a creep forming device for vacuum creep forming treatment to obtain the palladium composite membrane.

2. The method for connecting a palladium-based alloy thin film and a porous stainless steel carrier according to claim 1, wherein the sintering process in step one comprises: the aluminum silicate fiber paper is clamped between quartz glass, the quartz glass is placed in an electric furnace for sintering, the sintering temperature is 540-580 ℃, the heat preservation time is 40-60 min, then the quartz glass is cooled along with the furnace until the temperature is not higher than 150 ℃, the quartz glass is taken out of the furnace, and the surface of the quartz glass is subjected to pre-polishing and polishing treatment.

3. The method for bonding a palladium-based alloy thin film and a porous stainless steel carrier as claimed in claim 1, wherein the chemical composition of said aluminosilicate fiber paper in the first step includes Al₂O₃、SiO₂、ZrO₂And a binder.

4. The method of claim 1, wherein the palladium-based alloy thin film is a palladium-silver alloy thin film, a palladium-yttrium alloy thin film or a palladium-copper alloy thin film in the first step.

5. The method of claim 1, wherein in step two, the quartz glass is polished and polished in advance, and the porous stainless steel carrier is cleaned in advance with alcohol or acetone.

6. The method of claim 1, wherein the palladium-based alloy membrane is washed with alcohol or acetone in advance in step three.

7. The method according to claim 1, wherein a pressure-transmitting material, the porous stainless steel support, the palladium-based alloy film and quartz glass are sequentially and repeatedly stacked on the upper layer of the assembly in the third step, thereby obtaining a stacked assembly, wherein the height of the stacked assembly is smaller than the height of an effective heating zone in a vacuum hot-pressing sintering furnace, and the pressure-transmitting material and the porous stainless steel support are subjected to a pressing treatment, and the stacked assembly is sequentially subjected to a vacuum diffusion welding treatment and a vacuum creep forming treatment, thereby obtaining the palladium composite membrane.

8. The method for connecting a palladium-based alloy thin film and a porous stainless steel carrier according to claim 1, wherein the specific process of the vacuum creep forming treatment in the fifth step is as follows: placing the palladium-based alloy surface of the semi-finished product of the palladium composite membrane on a creep forming device, covering a layer of stainless steel foil with the same material as the porous stainless steel carrier on the upper surface of the semi-finished product of the palladium composite membrane, sealing and fixing the semi-finished product of the palladium composite membrane and the peripheral edges of the stainless steel foil, and keeping the vacuum degree in the device higher than 1.0 multiplied by 10^-3Heating to 680-720 ℃ under the condition of Pa, preserving heat for 15-20 min, and taking out the palladium composite membrane when the temperature in the device is lower than 100 ℃.

9. The method of claim 8, wherein the stainless steel foil is 304 stainless steel or 316L stainless steel, and the thickness of the stainless steel foil is 0.1mm to 0.2 mm.

Technical Field

The invention belongs to the technical field of metal material processing, and particularly relates to a method for connecting a palladium-based alloy film and a porous stainless steel carrier.

Background

The palladium metal has unique hydrogen permeation selectivity, namely hydrogen molecules are adsorbed on the surface of the palladium and dissociated into protons and electrons, the protons enter the crystal lattice of the palladium and diffuse along the direction of reducing the concentration gradient, and pass through the palladium metal, and on the other side of the palladium, the protons accept electrons from the metal and are reduced into hydrogen atoms, desorbed and re-associated to form hydrogen molecules. In the process, only hydrogen dissociated into protons can permeate metal palladium, so that the metal palladium is widely applied to the fields of extraction, separation and purification of hydrogen isotopes such as tritium separation of fission-fusion mixed reactors and tritium recovery in nuclear fusion research exhaust gas.

Many factors influence the hydrogen permeability of metal palladium, in order to improve the hydrogen permeability and the thermal stability and the antitoxic capability of palladium in hydrogen, a certain amount of alloy elements such as Ag, Cu, Y, Ni, Rh and the like are required to be added into the palladium to form palladium-based alloy, and the palladium-based alloy film is called as the palladium-based alloy film because the hydrogen permeability of the palladium is inversely proportional to the thickness of the palladium and the thickness of a practically applied palladium material in the industry is not more than 100 mu m. As the thickness of the palladium-based alloy thin film is reduced, its mechanical stability and thermal stability are deteriorated, and thus it is necessary to support it by means of a support having a porous structure, and the combination of the palladium-based alloy thin film and the porous support is referred to as a palladium composite membrane. In the palladium composite membrane, the material of the carrier can be ceramic, glass/quartz, stainless steel and the like, but the stainless steel with a porous structure is considered as the carrier with the most development prospect at present by comprehensively considering the factors such as the difference of the thermal expansion coefficients between the palladium-based alloy and the carrier, the forming performance, the processing cost and the like.

At present, the palladium composite membrane using porous stainless steel as a carrier has a plurality of preparation methods, such as vapor deposition, electroplating, chemical plating, spray-thermal decomposition and the like, and the common points of the technologies are that the palladium-based alloy in the composite membrane is prepared on the surface of the porous stainless steel, and the palladium-based alloy composite membrane has the advantages that the thickness of the palladium-based alloy membrane can be very small (generally not more than 5 mu m), but the defects are that the membrane layer is uneven in structure and lower in density; the self strength of the film is low, the stability is poor, and the service life is very limited particularly when the film is used in an environment of more than 500 ℃; the process is immature, and the preparation cost is high; the method is difficult to prepare large-size membranes and is still in the research stage at present. The traditional rolling technology is a method for producing metal foil by combining high-temperature smelting and mechanical rolling, has the characteristics of uniform and compact product structure, mature and stable process, low processing cost, easy preparation of large-size foil and the like, and the thickness of the pure palladium film produced at present can be controlled to be 1 mu m. The palladium-based alloy film produced by the traditional roll-to-roll technology is connected with the porous stainless steel carrier, so that the prepared palladium composite film is a key technology for obtaining large-size palladium composite films in the future. However, from the material connection perspective, the connection between the large-size thin film and the macroscopic bulk material has many technical difficulties, such as uneven pressure loading, even partial pressure loading, which affects the connection strength and bonding rate of the composite film; in the connection process, the chemical components of the palladium-based alloy film are changed, so that the subsequent hydrogen permeation performance of the composite film is influenced; controlling the deformation of the heterogeneous metal composite component and the like.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method for connecting a palladium-based alloy thin film and a porous stainless steel carrier, aiming at the defects of the prior art. The method comprises the steps of firstly carrying out compression molding treatment on a porous stainless steel carrier and a pressure transfer material, filling the pressure transfer material into pores of the porous stainless steel carrier, improving the flatness of the connecting surface of the porous stainless steel carrier, then carrying out vacuum diffusion welding treatment on a palladium-based alloy film and the porous stainless steel carrier, filling the pressure transfer material with elastic deformation capacity into a gap formed between the ultrathin palladium-based alloy film and a rigid pressure head, improving the uniform degree of the pressure of the palladium-based alloy film in the vacuum diffusion welding process, ensuring the effective welding of the palladium-based alloy film and the porous stainless steel carrier, and then carrying out vacuum creep forming treatment to ensure the flatness of the palladium composite film.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for connecting a palladium-based alloy film and a porous stainless steel carrier is characterized by comprising the following steps:

step one, preparing a pressure transmission material: selecting aluminum silicate fiber paper and sintering to obtain a pressure transmission material;

step two, profiling: placing the pressure transmission material obtained in the step one on the upper surface of quartz glass, then placing a porous stainless steel carrier on the upper surface of the pressure transmission material, covering a layer of quartz glass on the upper surface of the pressure transmission material, and finally placing the pressure transmission material on a hydraulic machine for compression treatment to obtain a combined body, wherein the pressure intensity of the compression treatment is 0.02-0.04 MPa, and the pressure maintaining time is 40-60 min;

step three, assembling: removing the upper quartz glass layer of the combined body obtained in the second step, covering a palladium-based alloy film on the upper surface of the porous stainless steel carrier, and covering the upper quartz glass layer on the upper surface of the palladium-based alloy film to obtain an assembled body, wherein the surface area of the porous stainless steel carrier is larger than that of the palladium-based alloy film;

step four, connection: and (3) placing the assembly obtained in the third step in a vacuum hot-pressing sintering furnace for vacuum diffusion welding treatment, wherein the specific process comprises the following steps: the vacuum degree in the vacuum hot-pressing sintering furnace is increased to 1.0 multiplied by 10^-3Pa above, then after the temperature in the furnace is raised to 780-820 ℃, starting a hydraulic system, keeping the temperature and pressure for 90-120 min when the pressure born by the assembly is 0.2-0.5 MPa, connecting the palladium-based alloy film with a porous stainless steel carrier, and removing the quartz glass and the pressure transfer material to obtain a palladium composite film semi-finished product;

step five, leveling: and (4) placing the semi-finished product of the palladium composite membrane obtained in the fourth step into a creep forming device for vacuum creep forming treatment to obtain the palladium composite membrane.

The invention takes the alumina silicate fiber paper as the pressure transmitting material, utilizes the characteristics of loose structure and good deformability of the alumina silicate fiber, enables the pressure transmitting material to be filled in the pores of the porous stainless steel carrier through compression treatment, enables the connecting surface of the palladium-based alloy film and the porous stainless steel carrier to be a plane, is beneficial to improving the compactness of the palladium composite film, simultaneously, the alumina silicate fiber paper is stable in high-temperature and high-pressure environment, has high strength, can not generate element diffusion, can not change the chemical composition of the palladium-based alloy film, ensures the hydrogen permeability of the finally prepared palladium composite film, is an integrated structure with high flexibility, can realize the complete separation of the alumina silicate fiber paper and the porous stainless steel carrier without treatment after the preparation of the palladium composite film, enables the pores of the porous stainless steel carrier to provide free paths for hydrogen to permeate the palladium composite film, and further enables the palladium composite film to have higher hydrogen permeation amount, the aluminum silicate fiber paper is used as a pressure transfer material and is effectively filled into a gap of a non-contact part through elastic deformation, so that the uniformity of the pressure of each part in the vacuum diffusion welding process of the ultrathin palladium-based alloy film is improved, and the effective welding of the palladium-based alloy film and a porous stainless steel carrier is further ensured; according to the invention, the aluminum silicate fiber paper is sintered to remove organic matters in the aluminum silicate fiber paper, so that pollution to the palladium-based alloy film and blockage to the pores of the porous stainless steel carrier are avoided, the connection stability of the palladium-based alloy film and the porous stainless steel carrier is improved, the hydrogen permeation capability of the palladium composite film is further ensured, meanwhile, the plastic deformation capability of the sintered aluminum silicate fiber paper is improved, the full filling of the pores of the porous stainless steel carrier is facilitated, and the compactness of the palladium composite film is further improved; the invention adopts flexible pressure transmission material and hard quartz glass to carry out compression treatment on the porous stainless steel carrier, controls the pressure to be 0.02 MPa-0.04 MPa and the pressure maintaining time to be 40 min-60 min, so that the aluminum silicate fiber paper passes throughThe upper layer and the lower layer of hard quartz glass are extruded and fully filled into the pores of the porous stainless steel carrier, and the connecting contact surface of the porous stainless steel carrier and the palladium-based alloy film is processed into a uniform plane, so that the porous stainless steel carrier is favorably and fully contacted with the palladium-based alloy film, and the tissue uniformity and the density of the prepared palladium composite film are favorably improved; the palladium-based alloy film and the porous stainless steel carrier are subjected to vacuum diffusion welding treatment, microscopic plastic deformation is generated on the micro unevenness of the welding surface of the palladium-based alloy film and the porous stainless steel carrier, the welded joint surface is promoted to reach the interatomic distance, the atoms are diffused mutually to realize the connection of the palladium-based alloy film and the porous stainless steel carrier, and the vacuum degree is controlled to be 1.0 multiplied by 10^{- 3}The temperature is controlled to be 780-820 ℃ and the pressure is controlled to be 0.2-0.5 MPa, so that the distance between atoms of the bonding surface of the palladium-based alloy film and the porous stainless steel carrier is achieved, the atoms are diffused mutually to realize welding, meanwhile, the temperature is controlled to be 780-820 ℃, the number of atoms in the activation state of the bonding interface can be increased, metal recrystallization or intermetallic compound generation can be avoided, the diffusion welding connection surface is in close contact, the interface structure is more uniform, the strength of the connection surface is higher, and the prepared palladium composite film is uniform in structure, good in compactness and stable in hydrogen permeability; because the shrinkage rates of the palladium-based alloy film and the porous stainless steel carrier after vacuum diffusion welding treatment are different, the structure of the prepared palladium composite film semi-finished product has bending deformation, and the palladium composite film semi-finished product is subjected to vacuum creep forming treatment, so that the palladium composite film semi-finished product is subjected to slow plastic deformation, and the flatness of the prepared palladium composite film is effectively ensured; the method directly connects the palladium-based alloy film and the porous stainless steel carrier by adopting a vacuum diffusion welding treatment mode, and compared with a mode of preparing the palladium-based alloy on the surface of the porous stainless steel carrier by adopting vapor deposition, electroplating, chemical plating, spray-thermal decomposition and other modes, the method has the advantages of simple operation, easily controlled thickness and size of the palladium-based alloy film, better tissue uniformity of the prepared palladium composite film, higher compactness of vacuum diffusion welding connection, and suitability for various sizes, in particular to batch of large-size palladium composite filmsAnd (4) production.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that the specific technological process of the sintering treatment in the first step is as follows: the aluminum silicate fiber paper is clamped between quartz glass, the quartz glass is placed in an electric furnace for sintering, the sintering temperature is 540-580 ℃, the heat preservation time is 40-60 min, then the quartz glass is cooled along with the furnace until the temperature is not higher than 150 ℃, the quartz glass is taken out of the furnace, and the surface of the quartz glass is subjected to pre-polishing and polishing treatment. By adopting the process parameters, organic matters in the aluminum silicate fiber paper are fully removed, and the aluminum silicate fiber paper is clamped between the quartz glass, so that the flatness of each part of the aluminum silicate fiber paper is improved, and the subsequent profiling treatment operation is facilitated; the quartz glass is polished to eliminate obvious scratches on the surface of the quartz glass, the surface of the quartz glass is polished to be mirror-surface effect and smooth and flat, the flatness degree of each part of the sintered alumina silicate fiber paper is ensured, and the sintered alumina silicate fiber paper is used as a pressure transfer material to facilitate the subsequent more uniform filling of pores of a porous stainless steel carrier.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that the chemical component of the aluminum silicate fiber paper in the step one comprises Al₂O₃、SiO₂、ZrO₂And a binder. The aluminum silicate fiber paper adopted by the invention mainly comprises Al₂O₃、SiO₂、ZrO₂The palladium composite membrane is low in organic matter content, stable in chemical composition, high in strength, high in flexibility and high in thermal stability, does not change the chemical composition of the prepared palladium composite membrane, is easy to separate from pores of a porous stainless steel carrier after being used as a pressure transfer material and connected and formed with the palladium composite membrane, and ensures the hydrogen permeation quantity of the palladium composite membrane.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that in the first step, the palladium-based alloy film is a palladium-silver alloy film, a palladium-yttrium alloy film or a palladium-copper alloy film. The palladium-silver alloy film, the palladium-yttrium alloy film and the palladium-copper alloy film which are high in hydrogen permeation rate and thermal stability are connected with the porous stainless steel carrier, so that the strength of the palladium-silver alloy film, the palladium-yttrium alloy film and the palladium-copper alloy film is improved, the prepared palladium composite film has the characteristics of high strength, high hydrogen permeation rate and high thermal stability, and the application range of the palladium composite film prepared by the method is expanded.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that in the second step, the quartz glass is subjected to grinding and polishing treatment in advance, and the porous stainless steel carrier is cleaned by alcohol or acetone in advance. According to the invention, the quartz glass is ground and polished, so that the surface of the quartz glass is smooth and flat, and further, the pressure transfer material clamped between the two quartz glasses and all parts of the porous stainless steel carrier are uniformly stressed, and the pressure transfer material is ensured to be uniformly filled in pores of the porous stainless steel carrier, so that the flatness of the contact surface of the porous stainless steel carrier and the quartz glass is favorably improved, and the combination degree of a subsequent palladium-based alloy film and the porous stainless steel carrier is favorably improved; through cleaning the porous stainless steel carrier, the obstruction of pollutants on the surface of the porous stainless steel carrier on the subsequent connection with the palladium-based alloy film is eliminated, the combination degree of the palladium-based alloy film and the porous stainless steel carrier is further ensured, and the connection difficulty is reduced.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that the palladium-based alloy film is cleaned by alcohol or acetone in advance in the third step. According to the invention, the surface of the palladium-based alloy film is cleaned in advance to remove external pollutants attached to the surface, so that the palladium-based pollutants are prevented from influencing atomic diffusion, the welding surface quality of vacuum diffusion welding is improved, the uniformity and the density of the prepared palladium composite film are ensured, and the palladium-based alloy film is cleaned by adopting alcohol or acetone, so that on one hand, the solubility of the alcohol and the acetone is strong, the pollutant removing capability is strong, and on the other hand, the alcohol and the acetone are volatile, and are not easy to remain on the surface of the palladium-based alloy film to cause secondary pollution.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that in the third step, the pressure transmitting material, the porous stainless steel carrier, the palladium-based alloy film and the quartz glass are sequentially and repeatedly stacked on the upper layer of the assembly in sequence to obtain the stacked assembly, the height of the stacked assembly is smaller than the height of an effective heating area in a vacuum hot-pressing sintering furnace, the pressure transmitting material and the porous stainless steel carrier are subjected to compression molding, and the stacked assembly is sequentially subjected to vacuum diffusion welding treatment and vacuum creep forming treatment to obtain the palladium composite film. By adopting the stacking mode, the porous stainless steel carrier after the multi-layer paired profiling treatment is separated from the palladium-based alloy film by the quartz glass, the porous stainless steel carrier is placed in the vacuum hot-pressing sintering furnace, and the vacuum diffusion welding treatment is carried out simultaneously, so that the space in the vacuum hot-pressing sintering furnace is fully utilized, the energy is saved, and the working efficiency is improved.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that the specific process of the vacuum creep forming treatment in the fifth step is as follows: placing the palladium-based alloy surface of the semi-finished product of the palladium composite membrane on a creep forming device, covering a layer of stainless steel foil with the same material as the porous stainless steel carrier on the upper surface of the semi-finished product of the palladium composite membrane, sealing and fixing the semi-finished product of the palladium composite membrane and the peripheral edges of the stainless steel foil, and keeping the vacuum degree in the device higher than 1.0 multiplied by 10^-3Heating to 680-720 ℃ under the condition of Pa, preserving heat for 15-20 min, and taking out the palladium composite membrane when the temperature in the device is lower than 100 ℃. By adopting the process parameters, the internal stress of the semi-finished product of the palladium composite membrane is fully released, the leveled palladium composite membrane is ensured not to generate rebound warping after being placed for a period of time, and the flatness of the palladium composite membrane is effectively improved; the stainless steel foil covered on the upper layer of the semi-finished product of the palladium composite membrane has certain roughness, can not be adhered, is easy to separate after heat treatment, and adopts the stainless steel foil with the same material as the porous stainless steel carrier, thereby ensuring the consistent deformability.

The method for connecting the palladium-based alloy film and the porous stainless steel carrier is characterized in that the stainless steel foil is made of 304 stainless steel or 316L stainless steel, and the thickness of the stainless steel foil is 0.1-0.2 mm. The adopted 304 stainless steel and 316L stainless steel contain molybdenum elements, have the characteristic of high temperature resistance, have stable chemical components in the high-temperature environment of the vacuum creep forming device, have higher strength, are covered on the semi-finished product of the palladium composite membrane, are favorable for deformation and leveling, and ensure the flatness of the finally prepared palladium composite membrane.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, the palladium-based alloy film and the porous stainless steel carrier are directly connected by adopting a vacuum diffusion welding treatment mode, compared with a mode of preparing the palladium-based alloy on the surface of the porous stainless steel carrier by adopting vapor deposition, electroplating, chemical plating, spray-thermal decomposition and other modes, the connection method disclosed by the invention is simple to operate, the thickness and the size of the palladium-based alloy film are easy to control, the tissue uniformity of the prepared palladium composite film is better, the connection density by adopting vacuum diffusion welding is higher, and the method is more suitable for batch production of the palladium composite films with various sizes, especially large sizes.

2. According to the invention, the aluminum silicate fiber paper with a loose structure and good deformability is used as a pressure transmission material, and in the vacuum diffusion welding process, the pressure transmission material is elastically deformed by the pressure applied by the rigid pressure head of the vacuum diffusion welding device and is effectively filled into a gap formed between the ultrathin palladium-based alloy film and the rigid pressure head, so that the uniform degree of the pressure applied to the palladium-based alloy film in the vacuum diffusion welding process is improved, and the effective welding of the palladium-based alloy film and the porous stainless steel carrier is further ensured.

3. According to the invention, the porous stainless steel carrier is subjected to compression molding treatment by adopting the flexible pressure transfer material and the hard quartz glass, so that the pressure transfer material is fully filled into the pores of the porous stainless steel carrier through the extrusion of the upper layer and the lower layer of the hard quartz glass, the connecting contact surface of the porous stainless steel carrier and the palladium-based alloy film is treated into a uniform plane, and the tissue uniformity and the density of the prepared palladium composite film are improved.

4. According to the invention, by adopting a vacuum creep forming treatment method, the bending deformation phenomenon caused by different shrinkage rates of the palladium-based alloy film and the porous stainless steel carrier after vacuum diffusion welding treatment is eliminated, so that the internal stress of the semi-finished product of the palladium composite film is fully released, and the flatness of the prepared palladium composite film is effectively ensured.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

FIG. 1 is a schematic structural view of a pressure-transmitting material of the present invention before being molded with a porous stainless steel support.

Fig. 2 is a schematic view of the structure of the composite obtained by the present invention.

FIG. 3 is a schematic structural view of an assembly obtained by the present invention.

Fig. 4 is a schematic structural view of a stacked assembly obtained by the present invention.

Fig. 5 is a schematic structural view of a palladium composite membrane prepared in example 3 of the present invention.

Fig. 6 is a cross-sectional structural view of the palladium composite membrane of fig. 5.

Description of reference numerals:

1-quartz glass; 2-porous stainless steel carrier; 3-a pressure transmitting material;

4-palladium-based alloy thin film.

Detailed Description

As shown in fig. 1, the structure of the pressure transmitting material 3 and the porous stainless steel carrier 2 before the pressing treatment is as follows: the porous stainless steel carrier 2 is arranged above the pressure transmission material 3, the porous stainless steel carrier 2 and the pressure transmission material 3 are integrally arranged between the upper quartz glass 1 and the lower quartz glass 1, and the size of the pressure transmission material 3 is slightly larger than that of the porous stainless steel carrier 2, so that the pores of the porous stainless steel carrier 2 can be filled with the pressure transmission material 3.

As shown in fig. 2, the structure of the assembly obtained by the present invention is: the pressure transmitting material 3 is filled into the pores of the porous stainless steel support 2 so that the upper surface of the porous stainless steel support 2 is a plane.

As shown in fig. 3, the assembly obtained by the present invention has a structure in which: covering a layer of palladium-based alloy film 4 on the upper surface of the pressed porous stainless steel carrier 2, covering quartz glass 1 above the palladium-based alloy film 4, and placing the structure into a vacuum hot-pressing sintering furnace for vacuum diffusion welding treatment.

As shown in fig. 4, the stacked assembly of the present invention has a structure in which: the method comprises the following steps of continuously stacking a pressed porous stainless steel carrier 2 above an assembly, covering a palladium-based alloy film 4 above the porous stainless steel carrier 2, sequentially stacking, placing a quartz glass 1 between each group of porous stainless steel carriers 2 and the palladium-based alloy film 4, covering a quartz glass 1 on the palladium-based alloy film 4 on the uppermost layer after stacking is completed, adjusting the number of stacked layers according to the height of an effective heating area of a vacuum hot-pressing sintering furnace and the stability after stacking, fully utilizing the effective space in the vacuum hot-pressing sintering furnace, improving the working efficiency of connection, and arranging fixing parts around the stacked assembly during actual use to ensure the stability of the stacked assembly in the vacuum diffusion welding process.

Example 1

The palladium composite membrane of the embodiment is formed by connecting a Pd77Ag23 film and a 316L porous stainless steel carrier, wherein the thickness of the Pd77Ag23 film is 20 μm, and the thickness of the 316L porous stainless steel carrier is 0.1 mm.

The method for connecting the Pd77Ag23 film and the 316L porous stainless steel carrier comprises the following steps:

step one, preparing a pressure transmission material: selecting TSX-1260 type alumina silicate fiber paper with the thickness of 2mm, clamping the alumina silicate fiber paper between quartz glass with the surface subjected to grinding and polishing, placing the alumina silicate fiber paper in an electric furnace for sintering, raising the temperature in the electric furnace to 540 ℃, preserving the heat for 40min, then cooling the alumina silicate fiber paper along with the furnace to 150 ℃, and discharging the alumina silicate fiber paper to obtain a pressure transfer material;

step two, profiling: placing the pressure transmission material obtained in the step one on the upper surface of the quartz glass subjected to grinding and polishing treatment, then placing a 316L porous stainless steel carrier on the upper surface of the pressure transmission material, covering a layer of quartz glass on the upper surface of the pressure transmission material, and finally placing the pressure transmission material on a hydraulic machine for compression treatment to obtain a combined body, wherein the pressure of the compression treatment is 0.02MPa, and the pressure maintaining time is 60 min;

step three, assembling: wiping off pollutants attached to the surface of the Pd77Ag23 film by using alcohol or acetone, removing the upper quartz glass of the assembly obtained in the step two, then covering the Pd77Ag23 film on the upper surface of the 316L porous stainless steel carrier, and covering the upper quartz glass on the upper surface of the Pd77Ag23 film to obtain an assembly;

step four, connection: placing the assembly obtained in the third step in a vacuum hot-pressing sintering furnace, and vacuumizing until the air pressure in the furnace is 1.0 multiplied by 10^-3When Pa is needed, starting the heating system, starting the hydraulic system after the furnace temperature is increased to 780 ℃, adjusting the pressure intensity born by the assembly to be assembled of the system to be 0.2MPa, keeping the temperature and the pressure for 120min, then cooling the assembly to the furnace temperature of 100 ℃ along with the furnace, discharging the assembly, and removing quartz glass and alumina silicate fiber paper to obtain a semi-finished product of the palladium composite film;

step five, leveling: placing the palladium alloy surface of the semi-finished product of the palladium composite membrane obtained in the fourth step on a creep forming device, covering a layer of 316L stainless steel foil with the thickness of 0.1mm on the upper surface, fixing and sealing the periphery, then starting a vacuum system, and vacuumizing until the air pressure in the furnace is 1.0 multiplied by 10^-3And when Pa is needed, starting the heating system, preserving heat at 680 ℃ for 20min to enable the palladium composite membrane to be completely attached with the membrane, closing the heating system, and taking out the palladium composite membrane when the temperature is reduced to 100 ℃ to obtain a final finished product.

Example 2

The palladium composite membrane of the embodiment is formed by connecting a Pd90Y10 film and a 304 porous stainless steel carrier, wherein the thickness of the Pd90Y10 film is 15 μm, and the thickness of the 304 porous stainless steel carrier is 0.15 mm.

The method for connecting the Pd90Y10 membrane and the 304 porous stainless steel carrier comprises the following steps:

step one, preparing a pressure transmission material: selecting TSX-1400 type alumina silicate fiber paper with the thickness of 2mm, clamping the alumina silicate fiber paper between quartz glass with the surface subjected to grinding and polishing, placing the alumina silicate fiber paper in an electric furnace for sintering, raising the temperature in the electric furnace to 580 ℃, preserving the heat for 60min, then cooling the alumina silicate fiber paper to 120 ℃ along with the furnace, and discharging the alumina silicate fiber paper to obtain a pressure transfer material;

step two, profiling: placing the pressure transmission material obtained in the step one on the upper surface of the quartz glass subjected to grinding and polishing treatment, then placing a 304 porous stainless steel carrier on the upper surface of the pressure transmission material, covering a layer of quartz glass on the upper surface of the pressure transmission material, and finally placing the pressure transmission material on a hydraulic machine for compression treatment to obtain a combined body, wherein the pressure intensity of the compression treatment is 0.04MPa, and the pressure maintaining time is 40 min;

step three, assembling: wiping off pollutants attached to the surface of the Pd90Y10 film by using alcohol or acetone, removing the upper quartz glass layer of the combined body obtained in the second step, then covering the Pd90Y10 film on the upper surface of the 304 porous stainless steel carrier, covering the upper quartz glass layer on the upper surface of the Pd90Y10 film to obtain an assembled body, continuously stacking the pressed 304 porous stainless steel carrier above the assembled body, covering the Pd90Y10 film on the upper surface of the 304 porous stainless steel carrier, and finally covering the quartz glass layer on the upper surface of the uppermost Pd90Y10 film to obtain a stacked assembled body;

step four, connection: placing the stacked assembly obtained in the third step in a vacuum hot pressing sintering furnace, and vacuumizing until the air pressure in the furnace is 9.0 multiplied by 10^-4When Pa is needed, starting a heating system, starting a hydraulic system after the furnace temperature rises to 820 ℃, adjusting the pressure intensity born by a to-be-assembled body of the system to be 0.5MPa, keeping the temperature and the pressure for 90min, then cooling the to-be-assembled body along with the furnace to the furnace temperature of 30 ℃, discharging the to-be-assembled body, and removing quartz glass and alumina silicate fiber paper to obtain two semi-finished products of the palladium composite membrane;

step five, leveling: placing the palladium alloy surface of the semi-finished product of the palladium composite membrane obtained in the fourth step on a creep forming device, covering a layer of 304 stainless steel foil with the thickness of 0.15mm on the upper surface, fixing and sealing the periphery, then starting a vacuum system, and vacuumizing until the air pressure in the furnace is 8.0 multiplied by 10^-4And when Pa is needed, starting the heating system, preserving heat at 720 ℃ for 15min to enable the palladium composite membrane to be completely attached with the membrane, closing the heating system, and taking out the palladium composite membrane when the temperature is reduced to 50 ℃ to obtain a final finished product.

Example 3

The palladium composite membrane of the present example was formed by connecting a Pd60Cu40 thin film and a 316L porous stainless steel support, wherein the thickness of the Pd60Cu40 thin film was 10 μm, and the thickness of the 304 porous stainless steel support was 0.2 mm.

The method for connecting the Pd60Cu40 membrane and the 316L porous stainless steel carrier comprises the following steps:

step one, preparing a pressure transmission material: selecting TSX-1400 type alumina silicate fiber paper with the thickness of 2mm, clamping the alumina silicate fiber paper between quartz glass with the surface subjected to grinding and polishing, placing the alumina silicate fiber paper in an electric furnace for sintering, raising the temperature in the electric furnace to 560 ℃, keeping the temperature for 50min, then cooling the electric furnace to 30 ℃ along with the electric furnace, discharging the electric furnace to obtain a pressure transmission material;

step two, profiling: placing the pressure transmission material obtained in the step one on the upper surface of the quartz glass subjected to grinding and polishing treatment, then placing a 316L porous stainless steel carrier on the upper surface of the pressure transmission material, covering a layer of quartz glass on the upper surface of the pressure transmission material, and finally placing the pressure transmission material on a hydraulic machine for compression treatment to obtain a combined body, wherein the pressure of the compression treatment is 0.03MPa, and the pressure maintaining time is 50 min;

step three, assembling: wiping off pollutants attached to the surface of the Pd60Cu40 thin film by using alcohol or acetone, removing the upper quartz glass of the combined body obtained in the step two, then covering the Pd60Cu40 thin film on the upper surface of the 316L porous stainless steel carrier, and covering the upper quartz glass on the upper surface of the Pd60Cu40 thin film to obtain an assembled body;

step four, connection: placing the assembly obtained in the third step in a vacuum hot-pressing sintering furnace, and vacuumizing until the air pressure in the furnace is 4.0 multiplied by 10^-4When Pa is needed, starting the heating system, starting the hydraulic system after the furnace temperature is increased to 800 ℃, adjusting the pressure intensity born by the assembly to be assembled of the system to be 0.3MPa, keeping the temperature and the pressure for 110min, then cooling the assembly to the furnace temperature of 40 ℃ along with the furnace, discharging the assembly, and removing quartz glass and alumina silicate fiber paper to obtain a semi-finished product of the palladium composite film;

step five, leveling: placing the palladium alloy surface of the semi-finished product of the palladium composite membrane obtained in the fourth step on a creep forming device, covering a layer of 316L stainless steel foil with the thickness of 0.2mm on the upper surface, fixing and sealing the periphery, then starting a vacuum system, and vacuumizing until the air pressure in the furnace is 5.0 multiplied by 10^-4And when Pa is needed, starting the heating system, preserving heat at 700 ℃ for 18min to enable the palladium composite membrane to be completely attached with the membrane, closing the heating system, and taking out the palladium composite membrane when the temperature is reduced to 40 ℃ to obtain a final finished product.

Fig. 5 is a schematic structural diagram of the palladium composite membrane prepared in this embodiment, and fig. 6 is a structural diagram of a cross section of the palladium composite membrane prepared in this embodiment, it should be noted that, in order to clearly show a two-layer structure of the palladium composite membrane, fig. 5 is a structure in which a palladium-based alloy thin film with a half area is composited on a porous stainless steel support, and it can be seen from fig. 6 that a connection surface between a palladium alloy layer and the porous stainless steel support layer is tight and has no gap, and the palladium composite membrane is flat and continuous and has no obvious defects.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, change and equivalent structural changes of the above embodiments according to the technical essence of the invention are still within the protection scope of the technical solution of the invention.