A Pd / (TaHfNbZr)N / TaZr composite membrane and its preparation method

Abstract

This invention discloses a Pd / (TaHfNbZr)N / TaZr composite membrane, comprising a TaZr layer and a (TaHfNbZr)N film layer and a Pd film layer sequentially deposited on the TaZr layer. The preparation method of this composite membrane is as follows: 1. Melting to prepare a TaZr alloy; 2. Machining to obtain a TaZr alloy sheet; 3. Forming a (TaHfNbZr)N film layer by magnetron sputtering combined with nitriding; 4. Depositing Pd catalyst seed crystals by magnetron sputtering; 5. Chemically plating Pd to obtain a multilayer film; 6. Annealing treatment. This invention achieves superior hydrogen permeation performance by incorporating a TaZr layer, and by placing a (TaHfNbZr)N film layer between the TaZr and Pd film layers, it suppresses interdiffusion at the interface between the TaZr and Pd film layers, thereby improving the hydrogen permeation performance of the composite membrane and extending its service life. The preparation process of this invention is simple, environmentally friendly, and suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen separation membrane materials and metal composite membrane technology, specifically relating to a Pd / (TaHfNbZr)N / TaZr composite membrane and its preparation method. Background Technology

[0002] Currently, palladium or palladium alloy membranes are the most commonly used hydrogen separation membranes. They utilize the catalytic dissociation of hydrogen molecules by metallic palladium and the rapid permeation of interstitial hydrogen atoms within palladium at high temperatures to achieve the separation or enrichment of hydrogen from other impurity gases. However, the high price of metallic palladium limits its widespread industrial application.

[0003] Tantalum (Ta), niobium (Nb), vanadium (V), and other group VB refractory transition metals have hydrogen permeability coefficients that are 1-2 orders of magnitude higher than palladium at suitable temperatures. They also possess good mechanical strength, are easy to mold into various shapes, and cost only a fraction of palladium, making them promising hydrogen separation membrane materials. However, group VB metals lack catalytic dissociation activity for hydrogen molecules and their surfaces easily form dense oxide films that hinder hydrogen atom permeation, resulting in relatively low actual hydrogen permeation rates. This significantly limits their application as hydrogen permeation separation membrane materials.

[0004] The conventional solution is to plate a palladium film on the surface of the group VB metal. However, when used at high temperatures, due to interdiffusion at the interface, after a certain period of hydrogen permeation, a compound of palladium and group VB metal is formed at the interface of the composite membrane, which leads to the degradation or even failure of the hydrogen permeation performance of the composite membrane. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a Pd / (TaHfNbZr)N / TaZr composite membrane. This composite membrane, by incorporating a TaZr layer, enhances the hydrogen adsorption capacity of Ta. Furthermore, the (TaHfNbZr)N membrane layer placed between the TaZr and Pd layers effectively suppresses interdiffusion at the TaZr and Pd membrane interfaces under high-temperature operation, preventing degradation and failure of the composite membrane's hydrogen permeation performance. This improves the hydrogen permeation performance of the composite membrane, extends its service life, and solves the problem of hydrogen permeation performance degradation caused by interdiffusion at the interface after palladium film deposition on group VB metal surfaces.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a Pd / (TaHfNbZr)N / TaZr composite membrane, characterized in that it includes a TaZr layer and a (TaHfNbZr)N film layer and a Pd film layer sequentially deposited on the TaZr layer, wherein the thickness of the Pd film layer is 0.3μm to 1.2μm, the (TaHfNbZr)N film layer is obtained by nitriding the TaHfNbZr high-entropy film, and the thickness is 0.05μm to 0.15μm, and the mass percentage of Zr in the TaZr layer is 1% to 8%.

[0007] In this invention, the Pd / (TaHfNbZr)N / TaZr composite membrane achieves this by setting the thickness of the Pd film layer to 0.3 μm to 1.2 μm, which reduces the amount of precious metal palladium used while ensuring the integrity of the Pd film layer. This simultaneously protects the tantalum alloy substrate and catalyzes hydrogen absorption. By setting the thickness of the (TaHfNbZr)N film layer to 0.05 μm to 0.15 μm, the interdiffusion between the Pd and TaZr layers is suppressed without affecting the hydrogen permeation performance of the composite membrane. By using the TaZr layer as the bottom layer, the composite membrane not only possesses the mechanical strength required for engineering applications but also exhibits a high hydrogen permeation rate. Furthermore, by limiting the Zr mass percentage in the TaZr layer to 1% to 8%, this invention effectively increases its hydrogen absorption capacity, thereby enhancing its hydrogen permeation ability.

[0008] The aforementioned Pd / (TaHfNbZr)N / TaZr composite membrane is characterized in that the mass percentage of Zr in the TaZr layer is 1% to 3%.

[0009] Meanwhile, this invention also discloses a method for preparing the Pd / (TaHfNbZr)N / TaZr composite membrane as described above, characterized in that the method includes the following steps:

[0010] Step 1: Mix tantalum briquettes and sponge zirconium evenly, and then melt them using an electric arc furnace to obtain TaZr alloy;

[0011] Step 2: Using machining methods, the TaZr alloy obtained in Step 1 is processed into thin sheets with a thickness of 0.3mm to 1.0mm and polished to obtain TaZr alloy sheets.

[0012] Step 3: A TaHfNbZr film is prepared on the surface of the TaZr alloy sheet obtained in Step 2 by magnetron sputtering, and then nitriding is performed to form a (TaHfNbZr)N film.

[0013] Step 4: Deposit Pd catalyst seed crystals on the surface of the (TaHfNbZr)N film layer formed in Step 3 using magnetron sputtering; the deposition time is 10 min to 20 min.

[0014] Step 5: Perform chemical plating of Pd on the surface of the (TaHfNbZr)N film layer deposited in Step 4 to obtain a multilayer film;

[0015] Step 6: Anneal the multilayer film obtained in Step 5 under an argon atmosphere at 500℃±10℃ to obtain a Pd / (TaHfNbZr)N / TaZr composite film.

[0016] The method described above is characterized in that the metal elements in the TaHfNbZr film layer in step three are in an equiatomic ratio of 1:1:1:1. TaHfNbZr films with equiatomic metal element ratios are easier to prepare and exhibit better thermal stability.

[0017] The above method is characterized in that the nitriding in step three uses a mixture of argon and nitrogen gas, the nitriding power is 100W to 150W, and the time is 30min to 50min.

[0018] The above method is characterized in that the chemical plating process of Pd in ​​step five is as follows: in a chemical plating Pd aqueous solution containing 5 g / L palladium chloride, 380 mL / L ammonia, and 45 g / L disodium EDTA, 10 mL / L hydrazine hydrate solution is added at 50℃±10℃, and Pd is chemically plated for 50 min±5 min.

[0019] The method described above is characterized in that the argon flow rate under nitrogen atmosphere protection in step six is ​​0.15 m³ / s. 3 / h~0.4m 3 / h.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention obtains a Pd / (TaHfNbZr)N / TaZr composite membrane by sequentially depositing a (TaHfNbZr)N film and a Pd film on a TaZr layer. By introducing Zr into the transition metal Ta to form a TaZr layer, the hydrogen adsorption capacity of Ta is effectively improved, giving the TaZr layer better hydrogen permeation performance. At the same time, the (TaHfNbZr)N film layer placed between the TaZr layer and the Pd film layer effectively inhibits the interdiffusion at the interface between the TaZr layer and the Pd film layer under high-temperature operation, avoiding the degradation and failure of the composite membrane's hydrogen permeation performance, thereby improving the hydrogen permeation performance of the composite membrane and extending its service life.

[0022] 2. The TaZr layer in the Pd / (TaHfNbZr)N / TaZr composite membrane of this invention has good mechanical strength and can be easily made into various shapes, meeting the hydrogen permeation needs of different fields. Moreover, its price is lower than that of Pb, reducing raw material costs and making it suitable for widespread application.

[0023] 3. This invention uses a smelting process to obtain TaZr alloy, and combines it with machining, magnetron sputtering and chemical plating processes to obtain Pd / (TaHfNbZr)N / TaZr composite film. The process is simple, environmentally friendly and suitable for large-scale production.

[0024] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0025] Example 1

[0026] The Pd / (TaHfNbZr)N / TaZr composite film of this embodiment includes a TaZr layer and a (TaHfNbZr)N film layer and a Pd film layer sequentially deposited on the TaZr layer. The thickness of the Pd film layer is 0.3 μm, and the (TaHfNbZr)N film layer is obtained by nitriding the TaHfNbZr high-entropy film and has a thickness of 0.05 μm. The mass percentage of Zr in the TaZr layer is 1%.

[0027] The preparation method of the Pd / (TaHfNbZr)N / TaZr composite membrane in this embodiment includes the following steps:

[0028] Step 1: Mix tantalum briquettes and sponge zirconium evenly, and then melt them using an electric arc furnace to obtain TaZr alloy;

[0029] Step 2: Using machining methods, the TaZr alloy obtained in Step 1 is processed into a thin sheet with a thickness of 0.3 mm and polished to a bright finish to obtain a TaZr alloy sheet.

[0030] Step 3: A TaHfNbZr film with an atomic ratio of 1:1:1:1 for each metal element is prepared on the surface of the TaZr alloy sheet obtained in Step 2 by magnetron sputtering. Then, nitriding is performed using a mixed gas of argon and nitrogen with a nitriding power of 100W and a time of 30min to form a (TaHfNbZr)N film.

[0031] Step 4: Deposit palladium particles, i.e., Pd catalyst seed crystals, on the surface of the (TaHfNbZr)N film layer formed in Step 3 using magnetron sputtering; the deposition time is 10 min.

[0032] Step 5: The (TaHfNbZr)N film layer with Pd catalyst seed crystal deposited in Step 4 is placed in a chemical Pd plating aqueous solution containing 5 g / L palladium chloride, 380 mL / L ammonia, and 45 g / L disodium EDTA. 10 mL / L hydrazine hydrate solution is added at 50℃±10℃, and Pd is chemically plated for 50 min±5 min to obtain a multilayer film.

[0033] Step Six: Place the multilayer film obtained in Step Five under an argon flow rate of 0.15 m³ / s.3 The Pd / (TaHfNbZr)N / TaZr composite membrane was obtained by annealing under an argon atmosphere of / h at 500℃±10℃.

[0034] Example 2

[0035] The Pd / (TaHfNbZr)N / TaZr composite film of this embodiment includes a TaZr layer and a (TaHfNbZr)N film layer and a Pd film layer sequentially deposited on the TaZr layer. The thickness of the Pd film layer is 1.2 μm, and the (TaHfNbZr)N film layer is obtained by nitriding the TaHfNbZr high-entropy film and has a thickness of 0.15 μm. The mass percentage of Zr in the TaZr layer is 3%.

[0036] The preparation method of the Pd / (TaHfNbZr)N / TaZr composite membrane in this embodiment includes the following steps:

[0037] Step 1: Mix tantalum briquettes and sponge zirconium evenly, and then melt them using an electric arc furnace to obtain TaZr alloy;

[0038] Step 2: Using machining methods, the TaZr alloy obtained in Step 1 is processed into a thin sheet with a thickness of 1.0 mm and polished to a bright finish, thus obtaining a TaZr alloy sheet.

[0039] Step 3: A TaHfNbZr film with an atomic ratio of 1:1:1:1 for each metal element is prepared on the surface of the TaZr alloy sheet obtained in Step 2 by magnetron sputtering. Then, nitriding is performed using a mixed gas of argon and nitrogen. The nitriding power is 150W and the time is 50min to form a (TaHfNbZr)N film.

[0040] Step 4: Deposit palladium particles, i.e., Pd catalyst seed crystals, on the surface of the (TaHfNbZr)N film layer formed in Step 3 using magnetron sputtering; the deposition time is 20 min.

[0041] Step 5: The (TaHfNbZr)N film layer with Pd catalyst seed crystal deposited in Step 4 is placed in a chemical Pd plating aqueous solution containing 5 g / L palladium chloride, 380 mL / L ammonia, and 45 g / L disodium EDTA. 10 mL / L hydrazine hydrate solution is added at 50℃±10℃, and Pd is chemically plated for 50 min±5 min to obtain a multilayer film.

[0042] Step Six: Place the multilayer film obtained in Step Five under an argon gas flow rate of 0.4 m³ / min. 3 The Pd / (TaHfNbZr)N / TaZr composite membrane was obtained by annealing under an argon atmosphere of / h at 500℃±10℃.

[0043] Example 3

[0044] The Pd / (TaHfNbZr)N / TaZr composite film of this embodiment includes a TaZr layer and a (TaHfNbZr)N film layer and a Pd film layer sequentially deposited on the TaZr layer. The thickness of the Pd film layer is 1.0 μm, and the (TaHfNbZr)N film layer is obtained by nitriding the TaHfNbZr high-entropy film and has a thickness of 0.1 μm. The mass percentage of Zr in the TaZr layer is 8%.

[0045] The preparation method of the Pd / (TaHfNbZr)N / TaZr composite membrane in this embodiment includes the following steps:

[0046] Step 1: Mix tantalum briquettes and sponge zirconium evenly, and then melt them using an electric arc furnace to obtain TaZr alloy;

[0047] Step 2: Using machining methods, the TaZr alloy obtained in Step 1 is processed into a thin sheet with a thickness of 0.6 mm and polished to a bright finish to obtain a TaZr alloy sheet.

[0048] Step 3: A TaHfNbZr film with an atomic ratio of 1:1:1:1 for each metal element is prepared on the surface of the TaZr alloy sheet obtained in Step 2 by magnetron sputtering. Then, nitriding is performed using a mixed gas of argon and nitrogen. The nitriding power is 130W and the time is 40min to form a (TaHfNbZr)N film.

[0049] Step 4: Deposit palladium particles, i.e., Pd catalyst seed crystals, on the surface of the (TaHfNbZr)N film layer formed in Step 3 using magnetron sputtering; the deposition time is 15 min.

[0050] Step 5: The (TaHfNbZr)N film layer with Pd catalyst seed crystal deposited in Step 4 is placed in a chemical Pd plating aqueous solution containing 5 g / L palladium chloride, 380 mL / L ammonia, and 45 g / L disodium EDTA. 10 mL / L hydrazine hydrate solution is added at 50℃±10℃, and Pd is chemically plated for 50 min±5 min to obtain a multilayer film.

[0051] Step Six: Place the multilayer film obtained in Step Five under an argon gas flow rate of 0.3 m³ / min. 3 The Pd / (TaHfNbZr)N / TaZr composite membrane was obtained by annealing under an argon atmosphere of / h at 500℃±10℃.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane, characterized in that, The Pd / (TaHfNbZr)N / TaZr composite film comprises a TaZr layer and a (TaHfNbZr)N film and a Pd film sequentially deposited on the TaZr layer. The Pd film has a thickness of 0.3 μm to 1.2 μm, and the (TaHfNbZr)N film is obtained by nitriding a high-entropy TaHfNbZr film with a thickness of 0.05 μm to 0.15 μm. The mass percentage of Zr in the TaZr layer is 1% to 8%. The method includes the following steps: Step 1: Mix tantalum briquettes and sponge zirconium evenly, and then melt them using an electric arc furnace to obtain TaZr alloy; Step 2: Using machining methods, the TaZr alloy obtained in Step 1 is processed into thin sheets with a thickness of 0.3mm~1.0mm and polished to obtain TaZr alloy sheets; Step 3: A TaHfNbZr film is prepared on the surface of the TaZr alloy sheet obtained in Step 2 by magnetron sputtering, and then nitriding is performed to form a (TaHfNbZr)N film. Step 4: Deposit Pd catalyst seed crystals on the surface of the (TaHfNbZr)N film layer formed in Step 3 using magnetron sputtering; the deposition time is 10 min to 20 min. Step 5: Perform chemical plating of Pd on the surface of the (TaHfNbZr)N film layer deposited in Step 4 to obtain a multilayer film; Step 6: Anneal the multilayer film obtained in Step 5 under an argon atmosphere at 500℃±10℃ to obtain a Pd / (TaHfNbZr)N / TaZr composite film.

2. The method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane according to claim 1, characterized in that, The mass percentage of Zr in the TaZr layer is 1% to 3%.

3. The method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane according to claim 1, characterized in that, In step three, the metal elements in the TaHfNbZr film are in an atomic ratio of 1:1:1:

1.

4. The method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane according to claim 1, characterized in that, The nitriding described in step three uses a mixture of argon and nitrogen gas, with a nitriding power of 100W~150W and a time of 30min~50min.

5. The method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane according to claim 1, characterized in that, The chemical plating process described in step five is as follows: In a chemical plating Pd aqueous solution containing 5 g / L palladium chloride, 380 mL / L ammonia, and 45 g / L disodium EDTA, 10 mL / L hydrazine hydrate solution is added at 50℃±10℃, and Pd is chemically plated for 50 min±5 min.

6. The method for preparing a Pd / (TaHfNbZr)N / TaZr composite membrane according to claim 1, characterized in that, In step six, the argon flow rate under the argon atmosphere protection is 0.15 m³ / s. 3 / h~0.4m 3 / h.