CN103774141A - Preparation method of tungsten coating component of plasma facing body - Google Patents

Abstract

The invention discloses a method for preparing a plasma-facing tungsten-coated component, which includes the following steps: (1) processing a chromium-zirconium-copper alloy substrate into a required geometric shape according to the size of the plasma-facing component; ( 2) Clean the surface of the processed chromium-zirconium-copper alloy substrate, remove the surface oxide layer, and keep the temperature of the substrate below 480°C, and form a 5-100μm layer on the surface of the chromium-zirconium-copper alloy substrate by physical vapor deposition. Thick copper intermediate adaptation layer with a purity higher than 99.9wt%; (3) Using tungsten hexafluoride gas as the raw material and hydrogen as the reducing gas, under the substrate temperature of 280-480°C, it is adapted in the middle of copper Chemical vapor deposition is carried out on the layer to form a tungsten coating with a thickness of 0.02-2mm, that is, the tungsten-coated part facing the plasma is produced. Compared with hot isostatic pressure diffusion welding, hot pressure diffusion welding, lamination rolling, explosive compounding, etc., the method of the present invention has simple process, low cost, easy realization and no environmental pollution.

Description

A process for the preparation of plasma-facing tungsten-coated components

technical field

The invention belongs to the technical field of metallurgical materials, and in particular relates to a preparation method of a tungsten-coated component facing plasma. the

Background technique

Tungsten has high melting point, excellent thermal conductivity, low sputtering yield and high self-sputtering threshold, low vapor pressure, and low tritium retention performance. It is considered to be the most promising divertor and divertor for fusion experimental devices and future fusion reactors. The first wall faces the plasma material. The plasma-facing components in the fusion device are required to have excellent thermal shock resistance, and at the same time, some components have complex shapes, which require convenient, simple and easy to replace. Due to the high hardness and high brittleness of tungsten, machining is very difficult. Coating technology has become an ideal method for preparing divertors and first wall parts with complex shapes. The preparation process is simple and economical, and it can be used without changing the structural conditions of the original parts. The change of plasma-facing material is easily accomplished under the control of plasma-facing components, although its resistance to thermal loads is slightly inferior to that of block-heat sink metallurgical connections, but for plasma-facing components below moderate wall loads (5-7MW/m ² ) , is undoubtedly the preferred production method.

Tungsten coating preparation technologies mainly include plasma spraying (PS), physical vapor deposition (physical vapor deposition), chemical vapor deposition (CVD) and other methods. Among them, PS has simple process, high preparation efficiency, low cost, can be repaired in situ and is not limited by the shape of the workpiece, so it is the preparation technology adopted by most researchers at present. However, the purity of PS tungsten coating is low, the density is only 90% of sintered pure tungsten, and the thermal conductivity is 25-60% lower than that of pure tungsten. In addition, the tensile strength of the PS tungsten coating is only 15% of that of sintered tungsten, and the bonding strength between the coating and the substrate is low, making it difficult to prepare a large area. The main problem of physical vapor deposition is low binding force and high impurity content (such as oxygen and carbon). At the same time, the tungsten coating obtained is only from a few microns to tens of microns thick, which is not very mature in general. The tungsten coating prepared by CVD has a high purity, which can reach more than 99.99%. The density, thermal conductivity and strength of the coating are equivalent to those of forged pure tungsten; the columnar crystal structure of CVD tungsten makes it have excellent high heat load resistance. The cracks only appear along the direction of the columnar crystals; at the same time, CVD can also deposit coatings on the surface of curved substrates, and can prepare coated parts with complex shapes. Therefore, CVD tungsten coating has a very good application prospect in the manufacture of plasma-facing components. the

At present, there are mainly the following methods for preparing plasma-facing components by CVD process:

Method 1: Depositing a tungsten coating on a substrate with a thermal expansion coefficient close to pure tungsten such as molybdenum (Mo), tungsten copper (W-copper) alloy by CVD method; (S.Tamura et al., Journal of Nuclear Materials307-311(2002) 735-738; J.Boscary et al., Fusion Engineering and Design39-40(1998)537-542; J.Song et al., Journal of Nuclear Materials442(2013)S208-S213)

Method 2: Deposit tungsten coating on substrates with good thermal conductivity and high plasticity such as pure copper (copper) or high-purity oxygen-free copper (OFHC) by CVD method; (J.Boscary et al., Fusion Engineering and Design39-40( 1998) 537-542; T.Hirai et al. Fusion Engineering and Design81(2006) 175-180）

Method 3: Deposit tungsten coating on chromium-zirconium copper alloy (chromium-zirconium-copper alloy) substrate by CVD method. Copper or OFHC is used as the intermediate adaptation layer between the substrate and the coating. The chromium-zirconium-copper alloy substrate is coated with a 1-3mm thick copper intermediate adaptation layer or the OFHC plate with a thickness of 1-3mm is welded to the chromium-zirconium-copper alloy substrate by hot isostatic pressing, and then Perform tungsten coating deposition. (Zhao Sixiang et al., water-cooled flat layered chromium-zirconium-copper alloy/OFHC-copper/CVD-W plasma-oriented components and its manufacturing method, patent application number 201210260306.1)

The following problems exist in the manufacture of plasma CVD tungsten coated parts by the above process:

(1) Method 1 uses materials such as molybdenum and tungsten copper as the base material, but the thermal conductivity of such materials is relatively low, so they are not suitable as heat sink materials for water-cooled modules;

(2) Method 2 uses copper or OFHC as the base material. Although the thermal conductivity is high, it is good for heat transfer, but the mechanical properties of the material are low, and it cannot be used as a structural material for water-cooled modules;

(3) The chromium-zirconium copper alloy used in method 3 is a deposition hardened copper alloy, which has good thermal conductivity and mechanical properties, and is widely selected as the first wall and divertor by the International Thermonuclear Experimental Reactor (ITER) and other fusion devices heat sink and construction materials. Copper or OFHC is often used as an intermediate adaptation layer to relieve the interfacial stress caused by the difference in thermal expansion coefficient between W and chromium-zirconium-copper alloy. Method 3 uses copper or OFHC with a thickness of 1-3 mm as the intermediate layer, which is difficult to achieve by electroplating and has high pollution; while the hot isostatic pressure process is used to diffuse the OFHC plate and the chromium-zirconium copper alloy substrate above 500 ° C. Together, this will greatly reduce the mechanical properties of the chromium-zirconium-copper alloy (the maximum service temperature of the chromium-zirconium-copper alloy is generally below 480°C), and the process is complicated and the cost is high. the

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a plasma-facing tungsten-coated component

Technical scheme of the present invention is as follows:

A method for preparing a plasma-facing tungsten-coated component, comprising the steps of:

(1) Process the chromium-zirconium-copper alloy substrate into the required geometric shape according to the size of the plasma-facing components;

(2) Clean the surface of the processed chromium-zirconium-copper alloy substrate, remove the surface oxide layer, and keep the temperature of the substrate below 480°C, and form a 5-100μm layer on the surface of the chromium-zirconium-copper alloy substrate by physical vapor deposition. A thick copper intermediate adaptation layer with a purity higher than 99.9 wt%;

(3) Using tungsten hexafluoride gas as the raw material and hydrogen as the reducing gas, chemical vapor deposition is carried out on the copper intermediate adaptation layer at a substrate temperature of 280-480°C to form tungsten with a thickness of 0.02-2mm Coating, ie making said plasma-facing tungsten-coated part. the

In a preferred embodiment of the present invention, the zirconium content of the chromium-zirconium-copper alloy substrate is 0.5-1.5 wt%, and the chromium content is 0.03-0.3 wt%. the

In a preferred embodiment of the present invention, the zirconium content of the chromium-zirconium-copper alloy substrate is 0.6-0.9 wt%, and the chromium content is 0.07-0.15 wt%. the

In a preferred embodiment of the present invention, in the step (2), the temperature of the substrate is kept below 300°C. the

In a preferred embodiment of the present invention, the thickness of the copper layer in the step (2) is 10-50 μm. the

In a preferred embodiment of the present invention, the temperature of the substrate in the step (3) is 300-450°C. the

In a preferred embodiment of the present invention, the thickness of the tungsten coating in step (3) is 0.05-0.5 mm. the

In a preferred embodiment of the present invention, the physical vapor deposition method includes sputter coating, ion plating and vacuum evaporation. the

The beneficial effects of the present invention are:

1. The method of the present invention adopts the physical vapor deposition method to form a 5-100 μm thick copper intermediate adaptation layer with a purity higher than 99.99wt% on the surface of the chromium-zirconium copper alloy substrate. The copper intermediate adaptation layer has good plasticity and can relieve chemical stress. The stress at the interface between the tungsten coating and the substrate during the preparation of the tungsten coating by vapor deposition and during the preparation of the plasma components, and the interface bonding force between the copper intermediate adaptation layer and the tungsten coating is relatively large;

2. The method of the present invention controls the temperature of the substrate below 480°C (preferably in the range of 350°C) during the physical vapor deposition process, maintaining the mechanical properties of the chromium-zirconium-copper alloy substrate;

3. Compared with hot isostatic pressure diffusion welding, hot pressure diffusion welding, lamination rolling, blasting compounding, etc., the method of the present invention has simple process, low cost, easy implementation, and will not pollute the environment;

4. Since the method of the present invention adopts physical vapor deposition to prepare the intermediate adaptation layer, the chromium-zirconium-copper alloy substrate can have complex geometric shapes and is not limited to a flat plate structure. Compared with hot isostatic pressure diffusion welding, hot pressure diffusion welding, Laminated rolling, explosive cladding and other processes have wide adaptability;

5. In the method of the present invention, the chromium-zirconium-copper alloy base material is first processed into the desired shape, and then the pure copper intermediate adaptation layer is prepared by physical vapor deposition, and then chemical vapor deposition is directly carried out to prepare the tungsten coating, and the intermediate adaptation The interface bonding force between layer copper and chromium-zirconium copper alloy substrate is good, especially when vacuum sputtering or ion plating is adopted, the plating property is good, the density is high, and there are no defects; while hot isostatic pressure diffusion welding and hot pressure diffusion Welding, lamination rolling, explosive composite and other processes need to connect the intermediate adaptation layer copper with the chromium-zirconium copper alloy substrate and then use machining methods to obtain the required geometry, and then perform chemical vapor deposition to prepare tungsten coating, the cutting force during machining can easily destroy the existing bond between the copper in the middle adaptation layer and the chromium-zirconium-copper alloy substrate, resulting in interface defects;

6. This method controls the thickness of the tungsten coating within the range of 0.02-2mm (preferably within the range of 0.05-0.5mm), and reduces the deposition temperature (that is, the temperature of the substrate) to a temperature range of 280-480°C ( Preferably in the range of 300-450°C), without reducing the mechanical properties of the chromium-zirconium-copper alloy substrate, at the same time, the deposition rate can be appropriately reduced, the grain size can be refined, the thermal and mechanical properties of the coating can be improved, and the coating thickness can be increased at the same time control accuracy and uniformity;

7. The method of the present invention can first weld the chromium-zirconium-copper alloy and other materials such as stainless steel to form a composite base material, and then obtain the required geometric shape by machining, and then weld the chromium-zirconium-copper alloy on the side of the composite base material Physical vapor deposition is carried out to prepare a copper intermediate adaptation layer, and finally a tungsten coating facing the plasma is prepared by chemical vapor deposition. the

Description of drawings

Fig. 1 is the cross-sectional structure schematic diagram of the flat tungsten coating module prepared by embodiment 1;

Fig. 2 is the cross-sectional structure schematic diagram of the complex shape tungsten coating module prepared in embodiment 2;

3 is a schematic diagram of the cross-sectional structure of the tungsten-coated stainless steel/chrome-zirconium-copper alloy composite substrate module prepared in Example 3. the

Detailed ways

The technical solutions of the present invention will be further illustrated and described below through specific embodiments. the

Example 1

This example is used to prepare a flat tungsten-coated module with rounded corners (as shown in Figure 1), and the specific implementation steps are as follows:

(1) The chromium-zirconium-copper alloy substrate 1 is processed into the required geometric shape according to the size of the plasma-facing component. The chromium-zirconium-copper alloy substrate 1 has a zirconium content of 0.5-1.5wt% and a chromium content of 0.03- 0.3wt%, further preferably, the zirconium content of the chromium-zirconium-copper alloy substrate 1 is 0.6-0.9wt%, and the chromium content is 0.07-0.15wt%;

(2) Clean the surface of the processed chromium-zirconium-copper alloy substrate 1, remove the surface oxide layer, ultrasonically neutralize with sodium carbonate solution, ultrasonically dehydrate with acetone and absolute alcohol, and finally blow dry with argon; The chamber is evacuated. When the vacuum degree is higher than 1.3×10 ^-2 Pa, turn on the heating power supply for heating and baking. When the heating temperature reaches 350°C and the vacuum degree reaches 3.0×10 ^-3 Pa, the baking and degassing process is completed; Fill the vacuum chamber with argon gas, turn on the bias power supply, and perform glow cleaning on the workpiece. The temperature of the glow cleaning is 200°C, the vacuum degree is 3-5Pa, the voltage is 1000V, and the cleaning time is 10 minutes; turn on the anaerobic Copper target magnetron sputtering power supply, prepare copper intermediate adaptation layer 2 on the surface of chrome-zirconium copper alloy substrate 1, the control parameters are: magnetron source power 6.6kW, pulse voltage 300-600V, duty cycle 20%, DC The voltage is 50-100V, the coating time is 7h, and the thickness of the copper intermediate adaptation layer 2 is 40μm. After the coating process is completed, continue to fill the vacuum chamber with argon gas, and take the workpiece out of the vacuum chamber after the workpiece is cooled. The above steps are realized on a magnetron sputtering coating machine.

(3) Put the above-mentioned chromium-zirconium-copper substrate 1 with the copper intermediate adaptation layer 2 into the chemical vapor deposition reaction chamber, and evacuate it to about 1.0×10 ^-1 Pa, blow it with nitrogen gas, and heat the substrate temperature to 300°C; feed tungsten hexafluoride raw material gas and reducing gas hydrogen, the molar ratio of the two is 1:3, chemical vapor deposition is carried out on the copper intermediate adaptation layer 2, the deposition time is 4h, and the tungsten coating 3 The thickness is 0.2 mm; after the deposition process is completed, continue to fill the vacuum chamber with nitrogen gas, and take the workpiece out of the reaction chamber after the workpiece is cooled, so as to obtain the tungsten-coated part facing the plasma.

Example 2

This example is used to prepare a complex-shaped tungsten-coated module (Figure 2). The specific implementation steps are as follows:

(1) The chromium-zirconium-copper alloy substrate 1 is processed into the required geometric shape according to the size of the plasma-facing component. The chromium-zirconium-copper alloy substrate 1 has a zirconium content of 0.5-1.5wt% and a chromium content of 0.03- 0.3wt%, further preferably, the zirconium content of the chromium-zirconium-copper alloy substrate 1 is 0.6-0.9wt%, and the chromium content is 0.07-0.15wt%;

(2) Clean the surface of the processed chromium-zirconium-copper alloy substrate 1 with acetone, remove the surface oxide layer, ultrasonically dehydrate with anhydrous alcohol, and finally blow dry with argon, and after infrared drying, put the sample into In the vacuum chamber of the multi-arc ion coating machine, place it on the workpiece table, vacuumize to 6×10 ^-3 Pa for pretreatment, pretreatment substrate bias voltage -450V, substrate pretreatment time 15min, use pure copper (purity greater than 99.9wt .%) target material, filled with argon gas with a partial pressure of 2×10 ^-2 Pa, an arc current of 60A, a substrate temperature of 220°C, a deposition substrate bias of -600V, a deposition time of 100min, and a copper intermediate adaptation layer 2 with a thickness of 90μm. After the coating process is finished, fill the vacuum chamber with argon gas, and take the workpiece out of the vacuum chamber after the workpiece is cooled.

(3) Put the above-mentioned chromium-zirconium-copper substrate 1 with the copper intermediate adaptation layer 2 into the chemical vapor deposition reaction chamber, and evacuate it to about 8.0×10 ^-1 Pa, blow it with nitrogen gas, and heat the substrate temperature to 450°C; feed tungsten hexafluoride raw material gas and reducing gas hydrogen, the molar ratio of the two is 1:2.5, chemical vapor deposition is carried out on the copper intermediate adaptation layer 2, the deposition time is 3h, and the tungsten coating 3 The thickness is 1 mm; after the deposition process is completed, continue to fill the vacuum chamber with nitrogen gas, and take the workpiece out of the reaction chamber after the workpiece is cooled, so as to obtain the tungsten-coated part facing the plasma.

Example 3

This example is used to prepare a stainless steel/chrome-zirconium-copper alloy composite substrate module containing a tungsten coating (Figure 3). The specific implementation steps are as follows:

(1) Process the welded 316L stainless steel 4 and the chromium-zirconium-copper alloy substrate 1 into a composite substrate of the required geometric shape according to the size of the plasma-facing components. The zirconium content of the chromium-zirconium-copper alloy substrate 1 is is 0.5-1.5wt%, and the chromium content is 0.03-0.3wt%, and further preferably, the zirconium content of the chromium-zirconium copper alloy 1 is 0.6-0.9wt%, and the chromium content is 0.07-0.15wt%;

(2) Clean the surface of the chromium-zirconium-copper alloy substrate 1 side of the composite substrate with acetone, remove the surface oxide layer, ultrasonically dehydrate with anhydrous alcohol, and finally dry it with argon, and dry the composite substrates (1 and 4 ) into the workpiece rack in the vacuum chamber of the vacuum evaporation machine, using high-purity oxygen-free copper (OFHC) as the plating material, placing it in a tungsten boat, evacuating to below 1.0×10 ^-2 Pa, and starting the heating in the vacuum chamber The device heats and degasses the substrate 6. The heating temperature is 200°C, and the temperature is maintained during the coating process until the coating is completed. A current of 80A is passed through the tungsten boat to heat to 1650°C. The deposition time is 8h, and the middle of the copper is adapted. The thickness of layer 2 is 20 μm. After the coating process is completed, argon gas is filled into the vacuum chamber, and the workpiece is taken out of the vacuum chamber after the workpiece is cooled.

(3) Put the composite substrate containing the copper intermediate adaptation layer 2 into the chemical vapor deposition reaction chamber, and evacuate it to about 8.0×10 ^-1 Pa, blow it with nitrogen gas, and heat the substrate temperature to 400°C; Feed tungsten hexafluoride raw material gas and reducing gas hydrogen, the molar ratio of the two is 1:2, chemical vapor deposition is carried out on the copper intermediate adaptation layer 2, the deposition time is 1h, and the thickness of the tungsten coating 3 is 0.1 mm; After the deposition process is completed, continue to fill the vacuum chamber with nitrogen gas, and take the workpiece out of the reaction chamber after the workpiece is cooled, so as to obtain the tungsten-coated part facing the plasma.

The above is only a preferred embodiment of the present invention, so the scope of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the content of the specification should still be covered by the present invention In the range. the

Claims (8)

1. a preparation method for the tungsten coating parts of plasma facing, is characterized in that: comprise the steps:

(1) chrome zirconium copper alloy base material is dimensioned to required geometrical shape according to Plasma facing components;

(2) by clean the surface cleaning of the chrome zirconium copper alloy base material processing, remove surface oxide layer, and keep the temperature of base material below 480 ℃, adopt physical vaporous deposition chrome zirconium copper alloy substrate surface form purity that 5-100 μ m is thick higher than the copper of 99.9wt% in the middle of adaptation layer;

(3) take tungsten hexafluoride as raw material, take hydrogen as reducing gas, under the base material temperature condition of 280-480 ℃, in the middle of copper, in adaptation layer, carry out chemical vapour deposition, to form the tungsten coating of 0.02-2mm thickness, make the tungsten coating parts of described plasma facing.

2. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 1, is characterized in that: the zirconium content of described chrome zirconium copper alloy base material is 0.5-1.5wt%, and chromium content is 0.03-0.3wt%.

3. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 2, is characterized in that: the zirconium content of described chrome zirconium copper alloy base material is 0.6-0.9wt%, and chromium content is 0.07-0.15wt%.

4. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 1, is characterized in that: described step remains on the temperature of base material below 300 ℃ in (2).

5. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 1, is characterized in that: the thickness of copper layer described in described step (2) is 10-50 μ m.

6. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 1, is characterized in that: the base material temperature in described step (3) is 300-450 ℃.

7. the preparation method of the tungsten coating parts of a kind of plasma facing as claimed in claim 1, is characterized in that: the thickness of the tungsten coating of described step (3) is 0.05-0.5mm.

8. the preparation method of the tungsten coating parts of a kind of plasma facing as described in arbitrary claim in claim 1 to 7, is characterized in that: described physical vaporous deposition comprises sputter coating, ion plating and vacuum evaporation.

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