Industrial preparation method of W / Cu composite material and its application

Abstract

An industrial preparation method of a W / Cu composite material and its application. The present invention belongs to the field of tungsten / copper composite materials for thermonuclear fusion. The purpose of the present invention is to solve the technical problem that the existing preparation method of tungsten / copper composite materials cannot take into account both production cost and product performance. The present invention uses W powder as a substrate, first co-deposits a WCu composite transition layer on its surface by magnetron sputtering, and then deposits a Cu film on the surface of the WCu composite transition layer by magnetron sputtering. This method solves the uneven mixing of traditional powders and the agglomeration of particles, and can make the distribution of W and Cu material components relatively uniform. In addition, more importantly, the present invention obtains a W / Cu composite material with both high density and thermal conductivity by regulating the thickness of the film layer on the surface of the W powder and the hot isostatic pressing process parameters matched thereto without increasing the preparation process and without introducing a third component filler, which provides the possibility for the industrial production of composite materials for the first wall of thermonuclear fusion plasma.

Description

Technical Field

[0001] The invention belongs to the field of tungsten / copper composite materials for thermonuclear fusion, and specifically relates to an industrial preparation method of a W / Cu composite material and application thereof. Background Art

[0002] The plasma first wall is a key component of a nuclear fusion reactor. It is located inside the reactor and directly faces the plasma. During the nuclear fusion reaction, its main function is to contain and confine high-temperature plasma. Since the plasma temperature is extremely high, reaching hundreds of millions of degrees Celsius, the first wall will absorb a large amount of heat and transfer the heat to the cooling system through heat conduction and other methods. The plasma first wall material faces extremely high heat loads, plasma scouring and neutron irradiation. Therefore, the first wall material must have a high melting point, high thermal shock resistance, high thermal conductivity, low vapor pressure and good radiation resistance.

[0003] W has a high melting point, can remain solid at high temperatures, can resist thermal shock, and has good tolerance to neutron irradiation. Cu has good thermal conductivity, and its good toughness can prevent the rapid expansion of cracks when the material is slightly damaged by irradiation. WCu alloy combines the high thermal conductivity of Cu and the high temperature resistance of W, so that heat can be efficiently transferred inside the material. It is considered to be one of the most promising plasma-facing (PFM) candidate materials in future nuclear fusion devices. However, the properties of W and Cu are quite different, and it is difficult to dissolve them, and the preparation process is difficult. To solve this problem, the prior art usually uses a spraying method to construct a transition layer between W and Cu to increase the mutual solubility of the two, but the transition layer obtained by spraying usually has uneven coating, and it is difficult to completely fill the powder particles, resulting in limited bonding strength and other problems. Another method is to use physical vapor deposition technology to wrap a uniform Cu film on the surface of tungsten powder to prepare W@Cu powder with a core-shell structure, thereby improving the density of the WCu alloy. However, the thermal conductivity of the tungsten / copper composite material obtained by this method still needs to be improved. In order to improve the thermal conductivity, thermal conductive fillers are usually added to the tungsten / copper composite material or introduced through additional treatment processes. The preparation process is complicated, which limits the large-scale industrial production of tungsten / copper composite materials. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the existing preparation method of tungsten / copper composite materials cannot take into account both production cost and product performance. The present invention provides an industrial preparation method of W / Cu composite materials and applications thereof.

[0005] One of the purposes of the present invention is to provide an industrial preparation method of a W / Cu composite material, the method being carried out according to the following steps:

[0006] S1: Using Cu target and W target as target materials respectively, co-depositing WCu composite transition layer on the surface of W powder by magnetron sputtering, turning off the W target, and continuing to deposit Cu film on the surface of WCu composite transition layer;

[0007] S2: Sintering the W / Cu composite material by hot isostatic pressing.

[0008] It is further defined that the particle size of the W powder in S1 is 5 to 15 μm.

[0009] It is further defined that the W powder in S1 is first subjected to ultrasonic-assisted alkaline washing and acid washing to remove grease and oxide layer on the surface of the W powder before use.

[0010] It is further defined that the magnetron sputtering parameters in S1 are: working gas pressure of 0.2-0.8 Pa, temperature of 200-300°C, bias voltage of -50V--150V, Cu target power of 50-150W, W target power of 2-4kW, co-deposition time of 1-12h, and deposition continues for 6h-20h after turning off the W target.

[0011] It is further defined that before magnetron sputtering in S1, the vacuum is first evacuated, and then Ar gas is introduced, and the W powder is cleaned with Ar gas at a vibration frequency of 5 to 10 Hz and a bias voltage of -50 V to -150 V.

[0012] It is further defined that the thickness of the WCu composite transition layer obtained in S1 is 50-600 nm, and the thickness of the Cu film obtained is 0.3-1 μm.

[0013] It is further defined that when the sum of the thickness of the WCu composite transition layer and the Cu film in S1 is ≤1 μm, the sintering temperature is 800-1000°C; when the sum of the thickness of the WCu composite transition layer and the Cu film is >1 μm, the sintering temperature is 1100-1200°C.

[0014] It is further defined that the hot isostatic pressing pressure in S2 is 80-100 MPa, the sintering temperature is 800-1200°C, and the holding time is 1-3 hours.

[0015] The second object of the present invention is to provide a W / Cu composite material prepared by the above method, wherein the composite material has a density greater than 98% and a thermal conductivity greater than 270 W / (m·K).

[0016] The third object of the present invention is to provide a plasma first wall, wherein the plasma first wall is made of the W / Cu composite material obtained by the above method.

[0017] A fourth object of the present invention is to provide an application of the above-mentioned plasma first wall in the field of thermonuclear fusion.

[0018] The advantages of the present invention compared to the prior art are:

[0019] The present invention uses W powder as a substrate, first co-deposit a WCu composite transition layer on its surface by magnetron sputtering, and then deposit a Cu film on the surface of the WCu composite transition layer by magnetron sputtering. This method solves the problems of uneven powder mixing and particle agglomeration in traditional methods, and can make the distribution of W and Cu material components relatively uniform. In addition, more importantly, the present invention obtains a W / Cu composite material with high density and thermal conductivity without increasing the preparation process and introducing a third component filler by regulating the thickness of the WCu composite transition layer and the hot isostatic pressing process parameters matched therewith, thus providing the possibility for the industrial production of composite materials for the first wall of thermonuclear fusion plasma. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the W@Cu powder of the present invention;

[0021] Figure 2 This is the microstructure of the W / Cu composite material obtained in Example 1. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0024] The terms "comprising," "including," "having," "containing," or any other variations thereof, as used in the following examples, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus comprising the listed elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0025] The endpoints and any values ​​of the ranges disclosed in the invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article.

[0026] Example 1: Combination Figure 1 The preparation method of the W / Cu composite material of this embodiment comprises the following steps:

[0027] (1) W powder ultrasonic cleaning

[0028] First, the W powder (particle size 5μm, purity 99.99%) was washed with a 15% NaOH solution for 15 minutes, deionized water for 5 minutes, then washed with a 15% HNO3 solution for 20 minutes, and deionized water for 5 minutes to remove grease and part of the oxide layer on the surface of the W powder. It was then placed in a 5% citric acid solution and washed at 60°C for 30 minutes, washed with deionized water for 20 minutes, and dried in a drying oven to obtain W powder with a clean surface.

[0029] (2) Magnetron sputtering to obtain W@Cu powder

[0030] Place the W powder prepared in step (1) in the vibration tank of the powder PVD coating equipment at a vibration frequency of 5 Hz. Draw a vacuum to 5×10 -4 Pa, 40 sccm Ar gas was introduced, the bias voltage was -100 V, and the Ar gas was used to clean the W powder for 15 minutes.

[0031] Cu target (purity of 99.99%) and W target (purity of 99.99%) were used as target materials, respectively. The working gas pressure was 0.5 Pa, the temperature was 250°C, the bias voltage was -100 V, the Cu target power was 100 W, the W target power was 3 kW, and the co-deposition was 4 hours to obtain a WCu composite transition layer with a thickness of 200 nm.

[0032] The W target was turned off and deposition was continued for 16 h to obtain a Cu film with a thickness of 800 nm on the surface of the WCu composite transition layer, thereby obtaining W@Cu powder.

[0033] (3) Hot isostatic pressing

[0034] The W@Cu powder was kept at a pressure of 90 MPa and a sintering temperature of 950°C for 2 hours and subjected to hot isostatic pressing to obtain a W / Cu composite material.

[0035] In the W / Cu composite material of this embodiment, a WCu transition layer and a Cu film are coated on the surface of the W powder by ultrasonic cleaning + magnetron sputtering. The WCu transition layer can improve the bonding force between Cu and W and serve as a heat-conducting connection channel between WCu. The powder uniformity is good. When the powder particle size and film thickness are large, the gaps between the powders can be further reduced under the hot isostatic pressing liquid phase sintering method, so that Cu can be completely filled in the W pores, and rearranged by capillary force, accelerating the densification of the material.

[0036] Example 2: Combination Figure 1 The preparation method of the W / Cu composite material of this embodiment comprises the following steps:

[0037] (1) Ultrasonic cleaning of W powder

[0038] First, the W powder (particle size 5μm, purity 99.99%) was washed with a 15% NaOH solution for 15 minutes, deionized water for 5 minutes, then washed with a 15% HNO3 solution for 20 minutes, and deionized water for 5 minutes to remove grease and part of the oxide layer on the surface of the W powder. It was then placed in a 5% citric acid solution and washed at 60°C for 30 minutes, washed with deionized water for 20 minutes, and dried in a drying oven to obtain W powder with a clean surface.

[0039] (2) Magnetron sputtering to obtain W@Cu powder

[0040] Place the W powder prepared in step (1) in the vibration tank of the powder PVD coating equipment at a vibration frequency of 5 Hz. Draw a vacuum to 5×10 -4 Pa, 40 sccm Ar gas was introduced, the bias voltage was -100 V, and the Ar gas was used to clean the W powder for 15 minutes.

[0041] Cu target (purity of 99.99%) and W target (purity of 99.99%) were used as target materials, respectively. The working gas pressure was 0.5 Pa, the temperature was 250°C, the bias voltage was -100 V, the Cu target power was 100 W, the W target power was 3 kW, and the co-deposition was 8 hours to obtain a WCu composite transition layer with a thickness of 400 nm.

[0042] The W target was turned off and deposition was continued for 16 h to obtain a Cu film with a thickness of 800 nm on the surface of the WCu composite transition layer, thereby obtaining W@Cu powder.

[0043] (3) Hot isostatic pressing

[0044] The W@Cu powder was kept at a pressure of 100 MPa and a sintering temperature of 1100°C for 2 hours and subjected to hot isostatic pressing to obtain a W / Cu composite material.

[0045] In the W / Cu composite material of this embodiment, a WCu transition layer and a Cu film are coated on the surface of the W powder by ultrasonic cleaning + magnetron sputtering. The WCu transition layer can improve the bonding force between Cu and W and serve as a heat-conducting connection channel between WCu. The powder uniformity is good. When the powder particle size and film thickness are large, the gaps between the powders can be further reduced under the hot isostatic pressing liquid phase sintering method, so that Cu can be completely filled in the W pores, and rearranged by capillary force, accelerating the densification of the material.

[0046] Example 3: Combination Figure 1 The preparation method of the W / Cu composite material of this embodiment comprises the following steps:

[0047] (1) Ultrasonic cleaning of W powder

[0048] First, the W powder (particle size 5μm, purity 99.99%) was washed with a 15% NaOH solution for 15 minutes, deionized water for 5 minutes, then washed with a 15% HNO3 solution for 20 minutes, and deionized water for 5 minutes to remove grease and part of the oxide layer on the surface of the W powder. It was then placed in a 5% citric acid solution and washed at 60°C for 30 minutes, washed with deionized water for 20 minutes, and dried in a drying oven to obtain W powder with a clean surface.

[0049] (2) Magnetron sputtering to obtain W@Cu powder

[0050] Place the W powder prepared in step (1) in the vibration tank of the powder PVD coating equipment at a vibration frequency of 5 Hz. Draw a vacuum to 5×10 -4 Pa, 40 sccm Ar gas was introduced, the bias voltage was -100 V, and the Ar gas was used to clean the W powder for 15 minutes.

[0051] Cu target (purity of 99.99%) and W target (purity of 99.99%) were used as target materials, respectively. The working gas pressure was 0.5 Pa, the temperature was 250°C, the bias voltage was -100 V, the Cu target power was 100 W, the W target power was 3 kW, and the co-deposition was 12 hours to obtain a WCu composite transition layer with a thickness of 600 nm.

[0052] The W target was turned off and deposition was continued for 16 h to obtain a Cu film with a thickness of 800 nm on the surface of the WCu composite transition layer, thereby obtaining W@Cu powder.

[0053] (3) Hot isostatic pressing

[0054] The W@Cu powder was kept at a pressure of 100 MPa and a sintering temperature of 1100°C for 2 hours and subjected to hot isostatic pressing to obtain a W / Cu composite material.

[0055] In the W / Cu composite material of this embodiment, a WCu transition layer and a Cu film are coated on the surface of the W powder by ultrasonic cleaning + magnetron sputtering. The WCu transition layer can improve the bonding force between Cu and W and serve as a heat-conducting connection channel between WCu. The powder uniformity is good. When the powder particle size and film thickness are large, the gaps between the powders can be further reduced under the hot isostatic pressing liquid phase sintering method, so that Cu can be completely filled in the W pores. However, the thickness of the transition layer is large, and internal stress is generated during the growth process, which leads to a decrease in density and thermal conductivity.

[0056] Comparative Example: The preparation method of the W / Cu composite material of this comparative example comprises the following steps:

[0057] (1) Ultrasonic cleaning of W powder

[0058] First, the W powder (particle size 5μm, purity 99.99%) was washed with a 15% NaOH solution for 15 minutes, deionized water for 5 minutes, then washed with a 15% HNO3 solution for 20 minutes, and deionized water for 5 minutes to remove grease and part of the oxide layer on the surface of the W powder. It was then placed in a 5% citric acid solution and washed at 60°C for 30 minutes, washed with deionized water for 20 minutes, and dried in a drying oven to obtain W powder with a clean surface.

[0059] (2) Magnetron sputtering to obtain W@Cu powder

[0060] Place the W powder prepared in step (1) in the vibration tank of the powder PVD coating equipment at a vibration frequency of 5 Hz. Draw a vacuum to 5×10 -4 Pa, 40 sccm Ar gas was introduced, the bias voltage was -100 V, and the Ar gas was used to clean the W powder for 15 minutes.

[0061] Using Cu target (purity of 99.99%) as the target material, the working gas pressure is 0.5 Pa, the temperature is 250°C, the bias voltage is -100 V, the Cu target power is 100 W, and the deposition time is 16 hours. A Cu film with a thickness of 800 nm is obtained on the surface of the W powder to obtain W@Cu powder.

[0062] (3) Hot isostatic pressing

[0063] The W@Cu powder was kept at a pressure of 90 MPa and a sintering temperature of 950°C for 2 hours and subjected to hot isostatic pressing to obtain a W / Cu composite material.

[0064] In the W / Cu composite material of this embodiment, a Cu film is directly coated on the surface of W powder by magnetron sputtering, and Cu is directly coated on W powder by hot isostatic pressing solid phase sintering.

[0065] The density, thermal conductivity, hardness and flexural strength of the W / Cu composite materials obtained in Examples 1-3 and the comparative example were tested, and the results are shown in Table 1.

[0066] Table 1 Properties of W / Cu composite materials

[0067]

[0068] The above are only preferred specific embodiments of the present invention, which are all different implementations based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An industrial preparation method of a W / Cu composite material, characterized in that: The method: S1: Using Cu target and W target as target materials respectively, co-depositing WCu composite transition layer on the surface of W powder by magnetron sputtering, turning off W target, and continuing to deposit Cu film on the surface of WCu composite transition layer; magnetron sputtering parameters: working pressure is 0.2~0.8Pa, temperature is 200~300℃, bias voltage is -50V~ -150V, Cu target power is 50~150W, W target power is 2~4kW, co-deposition time is 1~12h, and deposition is continued for 6h~20h after turning off W target; the thickness of WCu composite transition layer is 50~600nm, and the thickness of Cu film is 0.3~1μm; S2: Sintering it by hot isostatic pressing to obtain a W / Cu composite material, wherein when the sum of the thickness of the WCu composite transition layer and the Cu film in S1 is ≤1μm, the sintering temperature is 800~1000℃, the hot isostatic pressing pressure is 80~100MPa, and the holding time is 1~3h; when the sum of the thickness of the WCu composite transition layer and the Cu film is greater than 1μm, the sintering temperature is 1100~1200℃, the hot isostatic pressing pressure is 80~100MPa, and the holding time is 1~3h.

2. The method according to claim 1, characterized in that Before using the W powder in S1, the grease and oxidation layer on the surface of the W powder were removed by ultrasonic-assisted alkaline washing and acid washing.

3. The method according to claim 1, characterized in that Before magnetron sputtering in S1, vacuum is first evacuated, and then Ar gas is introduced. The W powder is cleaned with Ar gas at a vibration frequency of 5 to 10 Hz and a bias voltage of -50 V to -150 V.

4. The W / Cu composite material obtained by the method according to any one of claims 1 to 3, characterized in that: The composite material has a density greater than 98% and a thermal conductivity greater than 270 W / (m·K).

5. A plasma first wall, characterized in that: The plasma first wall is made of the W / Cu composite material according to claim 4.

6. Application of the plasma first wall according to claim 5 in the field of thermonuclear fusion.

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