CN116065122A - Composite deuterium storage coating for neutron launch tube and preparation method thereof - Google Patents

Abstract

The invention provides a composite deuterium storage coating material for a neutron emission tube and a preparation method thereof. The method comprises the steps of preparing a metal deuteride film by deposition on the surface of a metal transition layer, regulating and controlling the deuterium storage amount in a deposition coating by controlling the percentage of deuterium introduced in the sputtering process, improving the hydrogen embrittlement resistance and the deuterium storage performance of the coating on the premise of meeting the requirements of higher deuterium storage density and good thermal stability, and finally, depositing a protective layer on the surface of the deuterium storage film to improve the oxidation resistance and the carbonization resistance of the deuterium storage composite film.

Description

Composite deuterium storage coating for neutron launch tube and preparation method thereof

technical field

The invention relates to the technical field of neutron generation, in particular to a composite deuterium storage coating material for a neutron emission tube and a preparation method thereof.

Background technique

The neutron emission tube is a small accelerator neutron source. Its function is to seal the ion source, target and air pressure adjustment system in a ceramic tube, forming an electric vacuum device with a simple and compact structure and easy to use. The deuterium target, as a key component of the neutron emission tube and neutron generator, requires the deuterium target to have a high deuterium storage capacity. Since the neutron tube will be bombarded by a large beam of deuterium ions during operation, the surface temperature of the target film will increase accordingly. , also requires the target film to have high thermal stability. In addition, the binding strength, anti-hydrogen embrittlement performance, and anti-oxidation performance of the target film are all key factors affecting the quality of the deuterium target.

The neutron sources of neutron emission tubes and neutron generators at home and abroad mostly use molybdenum, tungsten, copper and other metals as the substrate, and the surface is plated with titanium, zirconium, scandium and other elements as the deuterium-absorbing film material. Studies have shown that titanium, as one of the metal materials with the highest hydrogen absorption density at present, has the characteristics of cheap price, simple preparation process of titanium film, and stable deuterium absorption. The deuterium film material can absorb high concentrations of deuterium and hydrogen isotope tritium, and can form a thin film on the metal substrate at the same time. The appropriate thickness of the titanium layer can ensure that the surface temperature is low enough to keep the total activity in the target unchanged. However, pure titanium film also has some defects as a deuterium-absorbing film: 1. The titanium film is easily polluted by elements such as O and C, and a layer of carbide or oxide film is formed on the surface, thereby affecting the deuterium absorption and release performance of the film; 2. 1. After the pure titanium film absorbs hydrogen, there will be a unique hydrogen embrittlement phenomenon, which will deteriorate the mechanical properties of the material, cause the target film to pulverize or fall off in one piece, and cause the high-voltage breakdown of the neutron tube; 3. The pure titanium film cannot reach a higher The ratio of deuterium to titanium has a lower neutron yield. For example, Huang WC et al. disclosed a method of Mg/Nb hydrogen storage composite film prepared by magnetron co-sputtering. Its follow-up requires a higher temperature and hydrogen partial pressure to complete the hydrogen absorption process. Although it can store hydrogen, it cannot Solve the problems of hydrogen embrittlement pulverization and low hydrogen absorption rate. In the invention of CN106544628A, a method for preparing a deuterium-containing metal film is proposed. During the sputtering deposition process, high-purity deuterium gas is introduced to directly form a deuterium-containing metal film, which can effectively avoid the hydrogen embrittlement and powder drop that occur when the pure metal film absorbs deuterium. However, it fails to solve the problem that oxides are easily formed on the surface of the deuterium storage film and affect the neutron yield.

Contents of the invention

The object of the present invention is to provide a composite deuterium storage coating material for neutron emission tubes and a preparation method thereof. By adopting the reactive magnetron sputtering method, a metal transition layer is deposited on the surface of the substrate to further enhance the bonding between the coating and the substrate strength. Deposition and preparation of metal deuteride films on the surface of the metal transition layer, the amount of deuterium storage in the deposited coating is regulated by controlling the percentage of deuterium gas introduced during the sputtering process, under the premise of satisfying the high deuterium storage density and good thermal stability , improve the anti-hydrogen embrittlement and deuterium storage performance of the coating, and finally deposit a protective layer on the surface of the deuterium storage film to improve the anti-oxidation and anti-carbonization performance of the deuterium storage composite film.

In order to solve the above technical problems, the present invention provides a composite deuterium storage coating material for a neutron launch tube, which includes a metal transition layer, an MD _x deuterium storage layer and a protective layer.

The invention also provides a neutron emission tube, which includes a base body, a metal transition layer attached to the base body in sequence, an MD _x deuterium storage layer and a protective layer.

Wherein, the base body adopts metal with high thermal conductivity.

Wherein, M in the MDx is one or more alloys of Mg, Ti, Ni, La, Co, Zr, Hf, Al.

Wherein, the x value in the MD _x deuterium storage layer refers to the atomic ratio of deuterium to titanium, which is 0.5-2.5.

Wherein, the total thickness of the metal transition layer, MD _x deuterium storage layer and protective layer is not more than 30 μm.

Wherein, the thickness of the metal transition layer is not more than 5.0 μm.

Wherein, the thickness of the MD _x deuterium storage layer is not more than 20 μm.

Wherein, the surface protection layer is palladium or palladium alloy, with a thickness of 0.1-5.0 μm.

The present invention also provides a preparation method for the composite deuterium storage coating material for the neutron launch tube, which includes:

In the first step, the surface of the substrate is polished to a roughness of Ra<0.8 μm, ultrasonically cleaned and dried to obtain a substrate material sample with a smooth and flat surface;

The second step is to prepare a metal transition layer by vapor deposition on the surface of the substrate;

In the third step, the MDx deuterium storage coating is prepared by vapor deposition on the metal transition layer;

The fourth step is to prepare a protective layer by vapor deposition on the MDx deuterium storage coating.

The vapor deposition method is a physical vapor deposition method.

The physical vapor deposition method can be selected from electron beam evaporation coating, magnetron sputtering coating, arc plasma coating, ion coating and molecular beam epitaxy coating.

Beneficial effects of the present invention

(1) The composite deuterium storage coating for a neutron launch tube of the present invention is composed of a metal transition inner layer, an MDx deuterium storage coating and a protective outer layer. The inner layer is a metal transition layer, because the thin film grains formed by sputtering are relatively dense and have good bonding force with the substrate, which can make the relatively loose TiDx layer and the substrate have a better connection. Fully reacted deuterium gas; MDx deuterium storage coating has the advantages of controllable composition, low equilibrium pressure, and high deuterium storage capacity; in addition, the outer protective layer can effectively avoid neutron production due to oxidation and carbonization of the deuterium storage layer. The problem of lowering the amount. (2) The preparation method of the MDx coating for deuterium storage in neutron emission tubes provided by the present invention is a physical vapor deposition process. The preparation method of the invention is simple and reliable, can store deuterium in the form of a metal compound, and the prepared thin film has small thickness, light weight and good binding force with the matrix.

The composite coating composed of the metal transition inner layer, the MDx deuterium storage coating and the protective outer layer is prepared on the surface of the metal structural material. The amount of deuterium stored in the deposited coating is regulated by the percentage of deuterium gas introduced during the physical vapor deposition process. Under the premise of satisfying high deuterium storage density and good thermal stability, the bonding strength between the coating and the substrate is further enhanced, and the anti-hydrogen embrittlement and anti-oxidation properties of the coating are improved. The composite coating consists of a structural material matrix, a metal transition layer, an MDx deuterium storage layer and a protective layer in sequence. The composite coating is prepared by physical vapor deposition, and the total thickness of the coating does not exceed 30 μm. The coating preparation process is simple, the cost is low, and a metal compound is used to store deuterium, which has the advantages of good air stability, low equilibrium pressure, and high deuterium storage capacity. Under the high temperature test at 600°C, the deuterium storage capacity can reach 7.9 wt%.

Description of drawings

Fig. 1 is the structural layout drawing of TiDx composite deuterium storage coating for neutron launch tube of the present invention;

Fig. 2 is the cross-sectional SEM figure of TiDx composite deuterium storage coating for neutron launch tube of the present invention;

Fig. 3 is the XRD spectrum of the TiDx composite deuterium storage coating for the neutron emission tube of the present invention.

Detailed ways

The invention provides a composite deuterium storage coating material for a neutron launch tube, which comprises a metal transition layer, an MD _x deuterium storage layer and a protective layer.

The invention also provides a neutron emission tube, which includes a base body, a metal transition layer attached to the base body in sequence, an MD _x deuterium storage layer and a protective layer.

The base is made of metal with high thermal conductivity, preferably one or more composites of oxygen-free copper, red copper, tungsten, and stainless steel.

The metal transition layer is one or more alloys of Mg, Ti, Ni, La, Co, Zr, Hf, Al.

M in the MDx is one or more alloys of Mg, Ti, Ni, La, Co, Zr, Hf, Al, preferably Ti.

The x value in the MD _x deuterium storage layer refers to the atomic ratio of deuterium to titanium, preferably 0.5-2.5.

The total thickness of the metal transition layer, MD _x deuterium storage layer and protective layer is not more than 30 μm, more preferably 0.3-30 μm.

The thickness of the metal transition layer is no more than 5.0 μm, more preferably 0.1-5.0 μm.

The thickness of the MD _x deuterium storage layer is no more than 20 μm, more preferably 0.1-20 μm.

The surface protection layer is further, the surface protection layer is palladium or a palladium alloy with a thickness of 0.1-5.0 μm.

The present invention also provides a preparation method for the composite deuterium storage coating material for the neutron launch tube, which includes:

In the first step, the surface of the substrate is polished to a roughness of Ra<0.8 μm, ultrasonically cleaned and dried to obtain a substrate material sample with a smooth and flat surface;

The second step is to prepare a metal transition layer by vapor deposition on the surface of the substrate;

In the third step, the MDx deuterium storage coating is prepared by vapor deposition on the metal transition layer;

The fourth step is to prepare a protective layer by vapor deposition on the MDx deuterium storage coating.

The vapor deposition method is a physical vapor deposition method.

The physical vapor deposition method can be selected from electron beam evaporation coating, magnetron sputtering coating, arc plasma coating, ion coating and molecular beam epitaxy coating.

The implementation of the present invention will be described in detail below with examples and accompanying drawings, so as to fully understand and implement the process of how to apply technical means to solve technical problems and achieve technical effects in the present invention.

Example 1

A preparation method for a composite deuterium storage coating for a neutron launch tube, comprising the following steps:

(1) Select oxygen-free copper as the base material, polish the base material on one side to a roughness of 0.1-2.0 μm, and use a pure titanium (Ti) target with a diameter of 100 mm for sputtering;

(2) Use a mechanical pump and a molecular pump to vacuumize the magnetron sputtering chamber in sequence until the vacuum degree reaches 2.0×10 ^-4 Pa;

(3) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 200W, the target base distance to 80mm, and obtain a pure Ti transition with a thickness of 0.2μm after 20min sputtering deposition layer;

(4) A pure titanium (Ti) target with a diameter of 100 mm is used to deposit and prepare a TiD _x deuterium storage coating on the pure Ti transition layer by reactive radio frequency sputtering;

(5) Introduce the mixed gas of working gas Ar gas and reaction gas D ₂ , where Ar:D ₂ =20:1sccm, adjust the coating deposition pressure to 0.8Pa, sputtering power to 200W, and target base distance to 80mm. A 1.0 μm thick TiD _x deuterium storage coating was deposited by reactive radio frequency magnetron sputtering for 2 hours.

(6) Adopting a pure palladium (Pd) target with a diameter of 100 mm on the TiD _x deuterium storage coating is deposited by radio frequency sputtering to prepare a Pd protective coating;

(7) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 150W, the target base distance to 80mm, and obtain a pure Pd protection with a thickness of 0.2μm after 30min sputtering deposition layer, and finally a Ti/TiD _x /Pd deuterium storage composite coating with a thickness of 1.4 μm is obtained, and its structural layout is shown in Figure 1.

The composite coating prepared in Example 1 is tested for titanium-deuterium ratio and deuterium storage capacity. The test results show that the bonding force between the coating and the substrate is 23N, and the bonding force is good, and the TiD _x deuterium storage coating has a titanium-deuterium ratio of Ti :D=1:1, the total deuterium storage capacity is about 4.3wt%.

Example 2

A preparation method for a composite deuterium storage coating for a neutron launch tube, comprising the following steps:

(1) Select oxygen-free copper as the base material, polish the base material on one side to a roughness of 0.1-2.0 μm, and use a pure titanium (Ti) target with a diameter of 100 mm for sputtering;

(2) Use a mechanical pump and a molecular pump to vacuumize the magnetron sputtering chamber in sequence until the vacuum degree reaches 2.0×10 ^-4 Pa;

(3) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 200W, the target base distance to 80mm, and obtain a pure Ti transition with a thickness of 0.2μm after 20min sputtering deposition layer;

(4) A pure titanium (Ti) target with a diameter of 100 mm is used to deposit and prepare a TiD _x deuterium storage coating on the pure Ti transition layer by reactive radio frequency sputtering;

(5) Introduce the mixed gas of working gas Ar gas and reaction gas D ₂ , where Ar:D ₂ =20:5sccm, adjust the coating deposition pressure to 0.8Pa, sputtering power to 200W, and target base distance to 80mm. A 1.1 μm thick TiD _x deuterium storage coating was deposited by reactive radio frequency magnetron sputtering for 2h.

(6) Adopting a pure palladium (Pd) target with a diameter of 100 mm on the TiD _x deuterium storage coating is deposited by radio frequency sputtering to prepare a Pd protective coating;

(7) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 150W, the target base distance to 80mm, and obtain a pure Pd protection with a thickness of 0.2μm after 20min sputtering deposition layer, and finally a Ti/TiD _x /Pd deuterium storage composite coating with a thickness of 1.5 μm is obtained, and its structural layout is shown in Figure 1.

The composite coating prepared in Example 2 is tested for titanium-deuterium ratio and deuterium storage capacity. The test results show that the bonding force between the coating and the substrate is 22N, and the bonding force is good, and the TiD _x deuterium storage coating has a titanium-deuterium ratio of Ti :D=1:1.5, the total deuterium storage capacity is about 5.7wt%.

Example 3

A preparation method for a composite deuterium storage coating for a neutron launch tube, comprising the following steps:

(1) Select oxygen-free copper as the base material, polish the base material on one side to a roughness of 0.1-2.0 μm, and use a pure magnesium (Mg) target with a diameter of 100 mm for sputtering;

(2) Use a mechanical pump and a molecular pump to vacuumize the magnetron sputtering chamber in sequence until the vacuum degree reaches 2.0×10 ^-4 Pa;

(3) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 200W, the target base distance to 80mm, and obtain a pure Ti transition with a thickness of 0.8μm after 1h sputtering deposition layer;

(4) Adopting a pure magnesium (Mg) target with a diameter of 100mm on the pure Mg transition layer adopts reactive radio frequency sputtering method to deposit and prepare MgD _x deuterium storage coating;

(5) Introduce the mixed gas of working gas Ar gas and reaction gas D ₂ , where Ar:D ₂ =20:8sccm, adjust the coating deposition pressure to 0.8Pa, sputtering power to 200W, and target base distance to 80mm. The 4.2μm thick MgD _x deuterium storage coating was deposited by reactive radio frequency magnetron sputtering for 6h.

(6) Adopting a palladium-copper alloy target with a diameter of 100mm on the MgD _x deuterium storage coating adopts radio frequency sputtering deposition to prepare a PdCu alloy protective coating;

(7) Introduce the working gas Ar gas, control the intake flow rate to 20sccm, adjust the sputtering pressure to 0.8Pa, the sputtering power to 150W, the target base distance to 80mm, and obtain a PdCu alloy protection with a thickness of 0.3μm after 20min sputtering deposition layer, and finally a Mg/MgD _x /PdCu deuterium storage composite coating with a thickness of 5.3 μm is obtained, and its structural layout is shown in Figure 1.

The composite coating prepared in Example 3 is tested for the ratio of magnesium to deuterium and the amount of stored deuterium. The test results show that the bonding force between the coating and the substrate is 26N, and the bonding force is good, and the metal deuterium ratio of the MgD _× deuterium storage coating is Mg :D=1:2.0, the total deuterium storage capacity is about 7.9wt%.

Example 4

A preparation method for a composite deuterium storage coating for a neutron launch tube, comprising the following steps:

(1) Use oxygen-free copper as the base material, polish the base material on one side to a roughness of 0.1-2.0 μm, and then use acetone, ethanol and deionized water to ultrasonically clean it before use;

(2) Use a mechanical pump and a molecular pump to vacuumize the evaporation coating chamber in sequence until the vacuum degree reaches 2.0×10 ^-4 Pa;

(3) Pure Ti particles with a particle size of 3-5 mm are used as an evaporation source to deposit a pure Ti transition layer on the substrate.

(4) Place the substrate on the center of the sample stage, and adjust the distance between the center of the substrate and the tungsten boat d=12-18cm. Turn on the electron beam power supply, slowly adjust the electron beam current to 70mA, open the baffle for evaporation deposition coating, and obtain a pure Ti transition layer with a thickness of 0.15 μm after 20 minutes of evaporation deposition;

(5) Adopting pure Ti particles with a particle diameter of 3-5 mm as an evaporation source on the pure Ti transition layer by reactive evaporation plating to prepare TiD _x deuterium storage coating;

(6) The reaction gas D ₂ is introduced, and the flow rate of the deuterium gas is controlled to be 10 sccm. Turn on the electron beam power supply, slowly adjust the electron beam current to 70mA, open the baffle plate for evaporative deposition coating, and obtain a TiD _x deuterium storage coating with a thickness of 0.5 μm by evaporative deposition after 60 minutes of reaction;

(7) adopting pure Pd particles with a particle diameter of 3-5 mm as an evaporation source to prepare a Pd protective coating by evaporation deposition on the TiD _x deuterium storage coating;

(8) Turn on the electron beam power supply, slowly adjust the electron beam current to 80mA, open the baffle for evaporation deposition coating, and obtain a pure Pd transition layer with a thickness of 0.2 μm after 20 minutes of evaporation deposition. Finally, a Ti/TiD _x /Pd deuterium storage composite coating with a thickness of 0.85 μm is obtained, and its structural layout is shown in Figure 1 .

The composite coating that embodiment 4 prepares is carried out titanium-deuterium ratio and storage deuterium amount test, and test result shows, coating and substrate binding force is 16N, and binding force is good, and the titanium-deuterium ratio of TiD _x composite deuterium storage coating is Ti:D=1:1.7, the total deuterium storage capacity is about 5.5wt%.

All of the above-mentioned primary implementations of this intellectual property rights are not intended to limit other forms of implementations of this new product and/or new method. Those skilled in the art will, with this important information, modify the above to achieve a similar implementation. However, all modifications or alterations to the new product based on the present invention belong to reserved rights.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention to other forms. Any skilled person who is familiar with this profession may use the technical content disclosed above to change or modify the equivalent of equivalent changes. Example. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims (10)

1. A composite deuterium storage coating material for a neutron emission tube is characterized in that: comprises a metal transition layer and MD _x A deuterium storage layer and a protective layer.

2. The composite deuterium storage coating material for neutron emitters according to claim 1, characterized in that: m in the MDx is one or more alloys in Mg, ti, ni, la, co, zr, hf, al.

3. The composite deuterium storage coating material for neutron emitters according to claim 1 or 2, characterized in that: the MD is _x The x value in the deuterium storage layer refers to the atomic ratio of deuterium to titanium, and is 0.5-2.5.

4. The composite deuterium storage coating material for neutron emitters according to claim 1 or 2, characterized in that: the metal transition layer, MD _x The total thickness of the deuterium storage layer and the protective layer does not exceed 30 μm.

5. The composite deuterium storage coating material for neutron emitters according to claim 1 or 2, characterized in that: the thickness of the metal transition layer is not more than 5.0 mu m.

6. The composite deuterium storage coating material for neutron emitters according to claim 1 or 2, characterized in that: the MD is _x The deuterium storage layer thickness does not exceed 20 μm.

7. The composite deuterium storage coating material for neutron emitters according to claim 1 or 2, characterized in that: the surface protection layer is palladium or palladium alloy, and the thickness is 0.1-5.0 mu m.

8. The method for preparing the composite deuterium storage coating material for a neutron emitter tube according to any one of claims 1 to 7, comprising:

firstly, polishing the surface of a substrate until the roughness Ra is less than 0.8 mu m, and ultrasonically cleaning and drying to obtain a substrate material sample with a smooth and flat surface;

secondly, depositing and preparing a metal transition layer on the surface of the matrix by a vapor deposition method;

thirdly, depositing and preparing an MDx deuterium storage coating on the metal transition layer by a vapor deposition method;

and fourthly, depositing and preparing a protective layer on the MDx deuterium storage coating by a vapor deposition method.

9. A neutron emitting tube, comprising: a substrate, the metal transition layer and MD sequentially attached on the substrate _x A deuterium storage layer and a protective layer.

10. The neutron emitting tube of claim 9, wherein: the matrix is made of metal with high heat conductivity coefficient.

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