Ultra-thin wall thickness palladium silver alloy capillary and preparation method thereof

Abstract

The invention discloses a method for preparing various ultra-thin wall tubes of palladium-silver alloys, and an ultra-thin wall palladium-silver alloy capillary tube with a wall thickness of 0.009-0.025 mm is obtained by the following preparation process. The method comprises the following steps: a: preparing a palladium-silver alloy ingot; b: hot forging the palladium-silver alloy; c: drilling holes by machining; d: rolling the tube blank by a three-roll cold rolling tube mill; e: using T10 spring steel as a long mandrel to draw the palladium-silver alloy tube blank to a wall thickness of 0.05 mm; f: using a ZnAl alloy as a mandrel or a BiSnAg alloy as a mandrel, the long mandrel is drawn to a wall thickness of 0.009-0.025 mm, and the mandrel is dissolved to obtain an ultra-thin wall palladium-silver alloy capillary tube. The palladium-silver alloy capillary tube prepared by the invention has a uniform wall thickness, no pollution on the inner surface, and meets the hydrogen purification requirements.

Description

Technical Field

[0001] The present invention relates to an ultra-thin wall thick silver-silver alloy capillary tube and a preparation method thereof Background Art

[0002] In recent years, the demand for pure hydrogen in many fields such as petroleum processing, material processing and fuel cells has continued, and the sharing and purification of hydrogen has received more and more attention. Among the many hydrogen separation technologies, palladium-silver alloy separation technology is a very promising method. Due to its unique hydrogen permeability, palladium-based membranes have been widely studied for many years. At present, it is in the stage of exploring and studying the physical and chemical processes on the surface of palladium-based membranes, and there is still a long way to go before industrialization can be achieved. The main obstacles to the practical application of palladium-based membranes are their high cost, low permeability, and susceptibility to hydrogen embrittlement. Although the use of palladium alloy membranes can reduce costs and alleviate the occurrence of hydrogen embrittlement, the addition of alloys significantly changes the catalytic activity of palladium, and this change is irregular. Therefore, ultra-thin-walled palladium-silver alloy pipes have become the key to separation technology at this stage.

[0003] Hydrogen permeability of palladium-silver alloy (350℃, 2.06MPa)

[0004] Summary of the invention

[0005] The object of the present invention is to provide an ultra-thin-wall palladium-silver alloy capillary and a preparation method thereof.

[0006] The technical solution adopted by the present invention is:

[0007] An ultra-thin wall thickness palladium silver alloy material, which is composed of the following components:

[0008] 75-77wt% palladium, 23-25wt% silver

[0009] a. Preparation of palladium-silver alloy ingots: palladium blocks with a purity of not less than 99.99% and silver blocks are prepared under vacuum conditions with 75-77wt% palladium and 23-25wt% silver. The alloy round ingots are treated with homogenization heat at 950℃ for 2.5 hours under high-purity nitrogen protection, and then water quenched after being taken out of the furnace. The surface of the round ingot is turned on a lathe to remove surface defects.

[0010] b. Palladium-silver alloy hot forging: hot forging at 900-950℃ to the diameter required for subsequent processing.

[0011] C. Machining requires drilling: Machining requires drilling to obtain a tube blank with a certain outer diameter and inner diameter.

[0012] d. The three-roller cold rolling mill rolls the tube to a wall thickness of 0.25 mm, with an intermediate annealing temperature of 900°C for 0.5-1 hour.

[0013] e. The palladium-silver alloy tube billet is drawn with T10 spring steel as a long mandrel to a wall thickness of 0.05 mm, with an intermediate annealing temperature of 870°C for 30 minutes.

[0014] f. ZnAl alloy or BiSnAg alloy (melting point 90°C) is used as the core rod, and the long core rod is drawn to a wall thickness of 0.009-0.025mm. After dissolving the core rod, an ultra-thin-wall palladium-silver alloy capillary is obtained. DETAILED DESCRIPTION

[0015] Example 1

[0016] a. Preparation of palladium-silver alloy ingots: palladium blocks with a purity of not less than 99.99% and silver blocks are prepared under vacuum conditions with a ratio of 77wt% palladium and 23wt% silver to obtain Φ25mm alloy round ingots. Heat treatment at 950℃ for 2.5 hours under high-purity nitrogen protection, and then quench with water. Lathe the surface of the round ingot to remove surface defects.

[0017] b. Palladium-silver alloy hot forging: 900-950℃ hot forging to Φ8mm.

[0018] c. Machine punching: Machine punching Φ5mm, Φ8ⅹ5ⅹ1.5mm (outer diameterⅹinner diameterⅹwall thickness) tube blank.

[0019] d. The three-roller cold rolling mill rolls the tube to a wall thickness of 0.25 mm, with an intermediate annealing temperature of 900°C for 0.5-1 hour. The rolling passes are shown in the following table:

[0020]

[0021] e. The palladium silver alloy tube billet is drawn with T10 spring steel as a long mandrel to a wall thickness of 0.05mm, with an intermediate annealing temperature of 870℃ and a time of 30 minutes. The drawing passes are as follows:

[0022]

[0023] f. ZnAl alloy is drawn to Φ3.76mm and used as a core rod to be inserted into the Φ3.86ⅹ3.76mm tube obtained in step e. The drawing is performed with a deformation of 7% per pass, and the total deformation between two annealings is 30%. The annealing temperature is 870°C and the time is 5 minutes. When annealing is required, the core rod is dissolved and removed with 10% sulfuric acid, and then a ZnAl alloy wire with a diameter less than 0.1mm of the inner diameter of the tube is inserted as a core rod. The above process is repeated. After multiple drawing passes, a Φ2.400mm wire is obtained. The core rod is dissolved with 10% sulfuric acid to obtain a Φ2.400ⅹ2.350ⅹ0.025mm (outer diameterⅹinner diameterⅹ

[0024] Ultra-thin wall palladium-silver alloy capillary with wall thickness (mm).

[0025] Example 2

[0026] a. Preparation of palladium-silver alloy ingots: palladium blocks with a purity of not less than 99.99% and silver blocks are prepared in a vacuum condition with a ratio of 75wt% palladium and 25wt% silver to obtain Φ25mm alloy round ingots. Heat treatment at 950℃ for 2.5 hours under high-purity nitrogen protection, and then quench with water. Lathe the surface of the round ingot to remove surface defects.

[0027] b. Palladium-silver alloy hot forging: 900-950℃ hot forging to Φ8mm.

[0028] c. Machine punching: Machine punching Φ5mm, Φ8ⅹ5ⅹ1.5mm (outer diameterⅹinner diameterⅹwall thickness) tube blank.

[0029] d. The three-roller cold rolling mill rolls the tube to a wall thickness of 0.25 mm, with an intermediate annealing temperature of 900°C for 0.5-1 hour. The rolling passes are shown in the following table:

[0030]

[0031]

[0032] e. The palladium silver alloy tube billet is drawn with T10 spring steel as a long mandrel to a wall thickness of 0.05mm, with an intermediate annealing temperature of 870℃ and a time of 30 minutes. The drawing passes are as follows:

[0033]

[0034] f. ZnAl alloy is drawn to Φ3.76mm and used as a mandrel to be inserted into the Φ3.86ⅹ3.76mm tube obtained in step e. Drawing is performed with a deformation of 7% per pass, and a total deformation of 30% between two annealings, with an annealing temperature of 870°C and a time of 5 minutes. When annealing is required, the mandrel is removed by dissolving with 10% sulfuric acid, and then a ZnAl alloy wire with a diameter less than 0.1mm of the inner diameter of the tube is inserted as a mandrel. The above process is repeated, and a Φ2.400mm wire is obtained after multiple drawing passes. The mandrel is dissolved with 10% sulfuric acid to obtain an ultra-thin-wall palladium-silver alloy capillary of Φ2.400ⅹ2.350ⅹ0.025mm (outer diameterⅹinner diameterⅹwall thickness).

[0035] The above-mentioned Φ2.400ⅹ2.350ⅹ0.025mm (outer diameterⅹinner diameterⅹwall thickness) pipe is poured with liquid BiSnAg alloy (melting point 90℃) under 100℃ water bath condition, cooled to room temperature, and the BiSnAg alloy solidifies to become a mandrel, and is drawn with a deformation of 5% per pass, and a total deformation of 25% between two annealings, with an annealing temperature of 780℃ and a time of 1 minute. When annealing is required, the BiSnAg alloy is melted by heating in a water bath and then flows out naturally, and the inner surface of the pipe is soaked and cleaned with 5% sulfuric acid. Repeat the above process, and after multiple drawing and annealing, an ultra-thin wall capillary of Φ0.900ⅹ0.882ⅹ0.009mm (outer diameterⅹinner diameterⅹwall thickness) is obtained.

Claims

1. A method for preparing an ultra-thin-wall palladium-silver alloy capillary, characterized in that: The steps include: a. Preparation of palladium-silver alloy ingots: palladium blocks and silver blocks with a purity of not less than 99.99%, with 75-77wt% palladium and 23-25wt% silver as ingredients, are prepared under vacuum conditions to obtain alloy round ingots; homogenization heat treatment at 950°C for 2.5 hours under high-purity nitrogen protection, and water quenching after being taken out of the furnace; lathe turning the round ingot surface to remove surface defects; b. Palladium-silver alloy hot forging: 900-950℃ hot forging to the diameter required for subsequent processing; C. Machining and punching: Machining and punching obtains a tube blank with a certain outer diameter and inner diameter; d. The three-roller cold rolling mill rolls the tube to a wall thickness of 0.25 mm, with an intermediate annealing temperature of 900°C for 0.5-1 hour; e. The palladium-silver alloy tube billet is drawn with T10 spring steel as a long mandrel to a wall thickness of 0.05 mm, with an intermediate annealing temperature of 870°C for 30 minutes; f. The palladium-silver alloy tube billet uses ZnAl alloy as a core rod or BiSnAg alloy as a core rod, and is drawn to a wall thickness of 0.009-0.025mm. After dissolving the core rod, an ultra-thin-wall palladium-silver alloy capillary is obtained.

2. The method for preparing an ultra-thin wall palladium-silver alloy capillary according to claim 1, characterized in that: The melting point of BiSnAg alloy is 90°C.

3. An ultra-thin wall palladium-silver alloy capillary, characterized in that: The ultra-thin-wall palladium-silver alloy capillary is prepared by the preparation method of claim 1 or 2.

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