A high binding force multi-gradient target system and a preparation method thereof

Abstract

The application relates to the nuclear technology field and discloses a high-bonding-force multi-gradient target system and a preparation method thereof. The multi-gradient target system comprises a substrate, a hydrogen diffusion layer arranged on the upper surface of the substrate, and a target material layer arranged on the surface of the hydrogen diffusion layer. The hydrogen diffusion layer takes a hydrogen diffusion material as a matrix, the matrix is dispersed with a doped element which is the same as the material of the substrate, and the content of the doped element in the hydrogen diffusion layer gradually decreases from bottom to top. The hydrogen diffusion layer of the target system is designed as a multi-layer gradient structure with different element proportions, the bonding force between the hydrogen diffusion layer and the substrate can be significantly improved, hydrogen diffusion and migration are also facilitated, the probability of film layer peeling and bubbling can be greatly reduced, and the service life of the target system is prolonged. The hydrogen diffusion layer with the multi-layer gradient structure is successfully constructed on the substrate by adopting the mode of multiple spraying and gradually reducing the spraying gun moving speed and hydrogen flow.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear technology, in particular to a high-bonding-force multi-gradient target system and a preparation method thereof. BACKGROUND

[0002] The boron neutron capture therapy system based on an accelerator provides an option for the treatment of recurrent cancer. The neutron source for cancer treatment should generate a monochromatic neutron beam with an energy of about 10 keV, which has a nuclear reaction with boron in cancer cells to produce rays that can kill cancer cells. The target system is a key component for generating neutrons in a boron neutron capture therapy device, and the stability of the hydrogen diffusion layer and the target material layer (such as a lithium layer or a beryllium layer) in the target system has an important influence on the stability and life of the neutron source. In particular, the hydrogen diffusion layer is provided between the target material layer (such as a lithium layer or a beryllium layer) and the substrate (such as a copper substrate) to slow down and stop protons that still have a certain energy after passing through the lithium layer, and has the functions of diffusion and accommodation of hydrogen atoms, which not only avoids the irradiation damage and deposition of incident protons in the copper substrate, but also reduces the accumulation of hydrogen atoms in the copper substrate.

[0003] Currently, the hydrogen diffusion layer and the target material layer are usually prepared by sputtering or evaporation. Taking a lithium target as an example, the nuclear reaction of lithium with high-energy protons produces gases such as hydrogen, which migrates between the lithium target layer and the hydrogen diffusion layer. When the gas migrates between the two material interfaces, it is easy to form bubbles or cause the film layer to peel off. Therefore, how to reduce the probability of film peeling or bubble formation is a key problem. SUMMARY

[0004] To solve the above technical problems, first, the present application provides a high-bonding-force multi-gradient target system. The hydrogen diffusion layer of the target system is designed as a multi-layer gradient structure with different element proportions, which can significantly improve the bonding force of the hydrogen diffusion layer and the substrate, and also helps the diffusion and migration of hydrogen, greatly reduces the probability of film peeling and bubble formation, and thus prolongs the service life of the target system.

[0005] The specific technical solutions of the present application are as follows:

[0006] In a first aspect, the present application provides a high-bonding-force multi-gradient target system, which comprises: a substrate, a hydrogen diffusion layer provided on the upper surface of the substrate, and a target material layer provided on the surface of the hydrogen diffusion layer. The hydrogen diffusion layer is based on a hydrogen diffusion material, and the hydrogen diffusion material is dispersed with a doped element which is the same as the material of the substrate. The content of the doped element in the hydrogen diffusion layer decreases in a multi-gradient manner from bottom to top.

[0007] The hydrogen diffusion layer of the target system is designed as a multi-layer gradient structure with different element proportions, which can significantly improve the bonding force of the hydrogen diffusion layer and the substrate, and also helps the diffusion and migration of hydrogen, greatly reduces the probability of film peeling and bubble formation, and thus prolongs the service life of the target system.

[0008] As a preference, the hydrogen diffusion coefficient of the hydrogen diffusion material is at least 10000 times of the hydrogen diffusion coefficient of the substrate material, which can be expressed as:

[0009]

[0010] In the formula, D is the hydrogen diffusion coefficient of the hydrogen diffusion material, D 基 is the hydrogen diffusion coefficient of the substrate material.

[0011] Further preferably, the hydrogen diffusion material is tantalum, vanadium, niobium, tantalum alloy or vanadium alloy.

[0012] As a preference, the material of the substrate is copper.

[0013] As a preference, the target material layer is a lithium target layer or a beryllium target layer.

[0014] As a preference, the surface of the target material layer is covered with an oxidation alleviating layer.

[0015] The oxidation alleviating layer functions to alleviate oxidation of the target material layer.

[0016] Further preferably, the material of the oxidation alleviating layer is TiN, Ti, Nb and / or their metal compounds.

[0017] In a second aspect, the present application provides a preparation method of the high bonding force multi-gradient target system, comprising the following steps: 1) spraying the hydrogen diffusion material on the surface of the substrate for multiple times to form a hydrogen diffusion layer with a multi-layer structure; wherein the spraying gun moving speed and the hydrogen flow rate are gradually reduced during the spraying.

[0018] 2) constructing a target material layer on the surface of the hydrogen diffusion layer.

[0019] The present application adopts the method of multiple spraying to construct the hydrogen diffusion layer with a multi-gradient layer on the substrate. Specifically, in the spraying process, when spraying the first layer, the kinetic energy and temperature of the hydrogen diffusion layer material are improved and controlled by adjusting the spraying gun moving speed and the hydrogen flow rate, so that the solid solution (i.e. the alloy of the substrate material and the hydrogen diffusion material) is formed in the collision process with the substrate, thereby laying a good foundation for the spraying of the next layer of hydrogen diffusion material. Then, the hydrogen diffusion material is sprayed layer by layer. Since the spraying gun moving speed and the hydrogen flow rate are gradually reduced, the hydrogen diffusion layer solid solution with gradient content ratio can be formed to improve the bonding force between the hydrogen diffusion layer and the substrate. At the same time, the gradient structure is more conducive to the diffusion and migration of hydrogen, which greatly reduces the formation of hydrogen bubbles.

[0020] Further, the present application finds that different hydrogen diffusion layer substrate materials have different requirements for specific spraying processes. Specifically:

[0021] When the hydrogen diffusion material is tantalum, multiple layers of tantalum are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 1000 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in mm / s; the hydrogen flow rate is V g = 11 + B*0.5*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in L / min.

[0022] Taking a copper substrate as an example, in the spraying process, when spraying for the first time, tantalum particles are deposited on the surface of the copper substrate, wherein the tantalum particles with certain kinetic energy interact with the copper substrate, part of the copper is wrapped on the deposited tantalum particles, and the copper-tantalum alloy is formed, which can further improve the binding force between the tantalum particles and the copper; when spraying subsequently, part of the copper in the solid alloy formed in the previous layer combines with the new tantalum particles to form a new copper-tantalum alloy, and since only part of the copper is recombined into the copper-tantalum alloy in each layer, the copper content gradually decreases.

[0023] When the hydrogen diffusion material is vanadium, multiple layers of vanadium are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 700 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in L / min; the hydrogen flow rate is V g = 7 + B*0.3*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in L / min.

[0024] When the matrix material of the hydrogen diffusion layer is a tantalum-vanadium alloy, multiple layers of tantalum-vanadium alloy are sprayed on the substrate in sequence by multiple spraying, wherein:

[0025] the spraying gun moving speed V n = 900 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in L / min;

[0026] the hydrogen flow rate is V g = 8.5 + B*0.4*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in L / min.

[0027] When the hydrogen diffusion material is niobium, multiple layers of niobium are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n= 850 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n in L / min; hydrogen flow V g = 8 + B*0.35*(N-n), B = 0.8-1.3, N is the total spraying times, V g in L / min.

[0028] As a preference, the total spraying times is 2-6; further preferably 4.

[0029] As a preference, in step 1), the substrate is first surface sandblasted, cleaned, dried.

[0030] Further preferably, the cleaning and drying is first ultrasonic cleaning with anhydrous ethanol, then cleaning with deionized water, and then blowing dry with nitrogen.

[0031] As a preference, in step 1), after forming the hydrogen diffusion layer, the product is treated by a dust filtration system, and then surface cleaned.

[0032] As a preference, it further comprises 3): constructing an oxidation relief layer on the surface of the target material layer.

[0033] Compared with the prior art, the beneficial effects of the present application are:

[0034] (1) The hydrogen diffusion layer of the target system is designed as a multilayer gradient structure with different element proportions in the present application, which can significantly improve the bonding force of the hydrogen diffusion layer and the substrate, and also helps the diffusion and migration of hydrogen, greatly reduces the probability of film peeling and blistering, and thus prolongs the service life of the target system.

[0035] (2) The present application adopts the method of multiple spraying with gradually reduced spraying gun moving rate and hydrogen flow, which can successfully construct a hydrogen diffusion layer with a multilayer gradient structure on the substrate. DETAILED DESCRIPTION

[0036] In order to enable the personnel in the technical field to better understand the present application, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments, and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts should belong to the scope of protection of the present application.

[0037] General embodiment

[0038] A high adhesion multi-gradient target system, comprising: a substrate, a hydrogen diffusion layer on the upper surface of the substrate, and a target layer on the surface of the hydrogen diffusion layer. The hydrogen diffusion layer is made of a hydrogen diffusion material, and the hydrogen diffusion material contains a doping element which is the same as the material of the substrate. The content of the doping element in the hydrogen diffusion layer decreases in a multi-gradient manner from bottom to top.

[0039] In some specific embodiments, the hydrogen diffusion coefficient of the hydrogen diffusion material is at least 10000 times that of the substrate material, which can be expressed as:

[0040]

[0041] In the formula, D is the hydrogen diffusion coefficient of the hydrogen diffusion material, and D 基 is the hydrogen diffusion coefficient of the substrate material.

[0042] In some more specific embodiments, the hydrogen diffusion material is tantalum, vanadium, niobium, tantalum alloy or vanadium alloy.

[0043] In some specific embodiments, the material of the substrate is copper.

[0044] In some specific embodiments, the target layer is a lithium target layer or a beryllium target layer.

[0045] In some specific embodiments, the surface of the target layer is further covered with an oxidation alleviation layer.

[0046] In some more preferred embodiments, the material of the oxidation alleviation layer is TiN, Ti, Nb and / or their metal compounds.

[0047] The preparation method of the above-mentioned high adhesion multi-gradient target system, comprising the following steps:

[0048] 1) A plurality of layers of hydrogen diffusion material are sequentially sprayed on the substrate by multiple spraying to form a hydrogen diffusion layer; wherein the spraying gun moving speed and hydrogen flow rate are gradually reduced during spraying.

[0049] In some more preferred embodiments, in step 1), the surface of the substrate is first sandblasted, cleaned and dried. Further preferably, the cleaning and drying are first ultrasonic cleaning with anhydrous ethanol, then cleaning with deionized water, and finally blowing dry with nitrogen.

[0050] 2) After forming the hydrogen diffusion layer, the product is treated by a dust filtration system, and then the surface is cleaned.

[0051] 3) The target layer and the oxidation alleviation layer are constructed on the surface of the hydrogen diffusion layer.

[0052] Wherein:

[0053] When the hydrogen diffusion material is tantalum, in step 1), multiple layers of tantalum are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 1000 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in unit of mm / s; the hydrogen flow rate V g = 11 + B*0.5*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in unit of L / min.

[0054] When the hydrogen diffusion material is vanadium, in step 1), multiple layers of vanadium are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 700 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in unit of L / min; the hydrogen flow rate V g = 7 + B*0.3*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in unit of L / min.

[0055] When the hydrogen diffusion material is tantalum-vanadium alloy, in step 1), multiple layers of tantalum-vanadium alloy are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 900 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in unit of L / min; the hydrogen flow rate V g = 8.5 + B*0.4*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in unit of L / min.

[0056] As preferred, the hydrogen diffusion material is tantalum-vanadium alloy, in step 1), multiple layers of tantalum-vanadium alloy are sprayed on the substrate in sequence by multiple spraying, wherein: the spraying gun moving speed V n = 850 + A*250*(N-n), A = 0.8-1.2, N is the total spraying times, V n is in unit of L / min; the hydrogen flow rate V g = 8 + B*0.35*(N-n), B = 0.8-1.3, N is the total spraying times, V g is in unit of L / min.

[0057] In some preferred embodiments, the total spraying times is 2-6; further preferably 4.

[0058] Specific embodiments and comparative examples

[0059] Embodiment 1

[0060] A preparation method of a high-bonding-force multi-gradient target system comprises the following steps:

[0061] 1) The surface of the copper substrate is treated by low-pressure sand blasting.

[0062] It should be noted that the sand blasting causes very little wear on the surface of the copper substrate, so that the original material of the copper substrate can be preserved; the oxide layer on the surface of the copper substrate is removed; and micro grooves are formed on the surface of the copper substrate, so as to improve the adhesion and corrosion resistance of the coating.

[0063] 2) The surface of the copper substrate is ultrasonically cleaned with anhydrous ethanol for 10 minutes, then cleaned with deionized water, and then dried with nitrogen, and then placed in a vacuum spraying chamber for spraying of a hydrogen diffusion material, wherein the hydrogen diffusion material can be tantalum, vanadium, niobium, tantalum alloy or vanadium alloy, and for example, the tantalum interacts with the copper substrate, and the tantalum particles are deposited on the surface of the copper substrate, wherein the tantalum particles with a certain kinetic energy interact with the copper substrate, and the deposited tantalum particles are wrapped with part of the copper and form a copper-tantalum alloy with the copper, so as to further improve the bonding force between the tantalum particles and the copper.

[0064] For example, the spraying parameters for good film quality of tantalum are as follows: the powder feeding gas pressure is 5.5 psi, the hydrogen flow rate is 11 L / min, the argon flow rate is 90 L / min, and the spraying gun moving speed is 1000 mm / s.

[0065] Considering that the nuclear reaction between lithium and high-energy protons produces hydrogen and other gases, and the gases are easy to form bubbles at the interface between the lithium layer and the hydrogen diffusion layer when migrating between the two materials, the present application adopts multiple variable parameter scanning to spray a multi-gradient hydrogen diffusion layer.

[0066] Specifically, to prepare a hydrogen diffusion layer of 30 microns, based on the above-mentioned spraying parameters for good film quality of tantalum, to realize the gradient preparation of the hydrogen diffusion layer, the spraying gun moving speed of the first layer of tantalum is about 2 times the typical film forming parameter. The present application has found through experimental research that after about 3 times of scanning and spraying, the proportion of copper in the tantalum can be almost negligible, so that the spraying gun moving speed V n of the fourth layer of tantalum is related to the current spraying layer number n as V n =1000+A*250*(4-n), A=1, the hydrogen flow rate is V g =11+B*0.5*(4-n), B=1. Then normal scanning and spraying can be carried out according to the designed thickness of the tantalum.

[0067] It should be noted that when spraying the first layer, a higher spray gun scanning speed and gas flow and power are used to increase the kinetic energy and temperature of tantalum, so that a tantalum-copper solid solution is formed during the collision with the copper substrate, thereby laying a good foundation for the spraying of the next layer of tantalum.

[0068] 3) After spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample enters a transition vacuum chamber, the surface of the sample is cleaned by argon blowing, and the surface of the sample is cleaned by ultrasonic cleaning, after cleaning, the sample is placed in an evaporation chamber for lithium layer evaporation, after evaporation is completed, the sample is placed in a magnetron sputtering chamber for preparation of an oxidation alleviation layer (TiN), and a high-bonding multi-gradient target system is obtained.

[0069] Comparative Example 1

[0070] The main difference between the comparative example and example 1 is that the process parameters remain unchanged during multiple spraying processes.

[0071] A target system preparation method comprises the following steps:

[0072] 1) The surface of the copper substrate is treated by low-pressure sand blasting.

[0073] 2) The surface of the copper substrate is ultrasonically cleaned with anhydrous ethanol for 10 minutes, then cleaned with deionized water, and then dried with nitrogen, and then placed in a vacuum spraying chamber for spraying of a hydrogen diffusion layer substrate material (tantalum).

[0074] The spraying parameters are: powder feeding gas pressure is 5.5 psi, hydrogen flow is 11 L / min, argon flow is 90 L / min, and the spray gun moving speed is 1000 mm / s. The spraying is performed 4 times to obtain a 30-micron hydrogen diffusion layer.

[0075] 3) After spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample enters a transition vacuum chamber, the surface of the sample is cleaned by argon blowing, and the surface of the sample is cleaned by ultrasonic cleaning, after cleaning, the sample is placed in an evaporation chamber for lithium layer evaporation, after evaporation is completed, the sample is placed in a magnetron sputtering chamber for preparation of an oxidation alleviation layer (TiN), and a target system is obtained.

[0076] Example 2

[0077] The main difference between the example and example 1 is that the substrate material of the hydrogen diffusion layer is vanadium.

[0078] A high-bonding multi-gradient target system preparation method comprises the following steps:

[0079] 1) The surface of the copper substrate is treated by low-pressure sand blasting.

[0080] 2) ultrasonic cleaning the surface of the copper substrate with anhydrous ethanol for 10 minutes, then cleaning with deionized water, then blowing off the moisture with nitrogen, then placing in a vacuum spraying chamber to spray a hydrogen diffusion layer substrate material, wherein the hydrogen diffusion layer substrate material is vanadium.

[0081] For vanadium, the spraying parameters for good film quality are: powder feeding gas pressure of 5.5 psi, hydrogen flow rate of 7 L / min, argon flow rate of 70 L / min, and spray gun moving rate of 700 mm / s.

[0082] Specifically, a 30-micron hydrogen diffusion layer is prepared, based on the above-mentioned spraying parameters for good vanadium film quality, the spray gun moving rate V n The relationship with the current spraying layer number n is V n = 700 + A*250*(4-n), A = 1, hydrogen flow rate V g = 7 + B*0.3*(4-n), B = 1. Then normal scanning spraying is performed according to the designed thickness of tantalum.

[0083] 3) After spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is then cleaned, and then the sample is placed in a transition vacuum chamber, the surface of the sample is cleaned with argon, and the surface of the sample is cleaned by ultrasonic cleaning, after cleaning, the sample is placed in an evaporation chamber to evaporate a lithium layer, after evaporation is completed, the sample is placed in a magnetron sputtering chamber to prepare an oxidation relief layer (TiN), and a high-bonding-force multi-gradient target system is obtained.

[0084] Comparative Example 2

[0085] The main difference between this comparative example and Example 2 is that the process parameters remain unchanged during multiple spraying processes.

[0086] A target system preparation method, comprising the following steps:

[0087] 1) The surface of the copper substrate is treated by low-pressure sandblasting.

[0088] 2) ultrasonic cleaning the surface of the copper substrate with anhydrous ethanol for 10 minutes, then cleaning with deionized water, then blowing off the moisture with nitrogen, then placing in a vacuum spraying chamber to spray a hydrogen diffusion layer substrate material, wherein the hydrogen diffusion layer substrate material is vanadium.

[0089] The spraying parameters are: powder feeding gas pressure of 5.5 psi, hydrogen flow rate of 7 L / min, argon flow rate of 70 L / min, and spray gun moving rate of 700 mm / s, and a 30-micron hydrogen diffusion layer is prepared.

[0090] 3) After the spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample enters a transition vacuum chamber, the surface of the sample is blown by argon, the surface of the sample is cleaned by ultrasonic cleaning, after the cleaning is completed, the sample is placed in an evaporation chamber to evaporate a lithium layer, after the evaporation is completed, the sample is placed in a magnetron sputtering chamber to prepare an oxidation alleviation layer (TiN), and a target system is obtained.

[0091] Example 3

[0092] The main difference between the present example and example 1 is that the substrate material of the hydrogen diffusion layer is a tantalum-vanadium alloy.

[0093] A method for preparing a high-bonding-force multi-gradient target system, comprising the following steps:

[0094] 1) The surface of the copper substrate is treated by low-pressure sand blasting.

[0095] 2) The surface of the copper substrate is ultrasonically cleaned with anhydrous ethanol for 10 minutes, then cleaned with deionized water, and then dried with nitrogen, and then placed in a vacuum spraying chamber to spray a hydrogen diffusion layer substrate material, wherein the hydrogen diffusion layer substrate material is a tantalum-vanadium alloy.

[0096] For the tantalum-vanadium alloy, the spraying parameters for better film formation quality are: powder feeding gas pressure is 5.5 psi, hydrogen flow rate is 8.5 L / min, argon flow rate is 79 L / min, and spray gun moving rate is 900 mm / s.

[0097] Specifically, a 30-micron hydrogen diffusion layer is prepared, based on the above-mentioned spraying parameters for better film formation quality of the tantalum-vanadium alloy, the spray gun moving rate V n is in the relationship V n = 900 + A*250*(4-n), A=1, hydrogen flow rate V g = 8.5 + B*0.3*(4-n), B=1. Then normal scanning spraying can be performed according to the designed thickness of tantalum.

[0098] 3) After the spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample enters a transition vacuum chamber, the surface of the sample is blown by argon, the surface of the sample is cleaned by ultrasonic cleaning, after the cleaning is completed, the sample is placed in an evaporation chamber to evaporate a lithium layer, after the evaporation is completed, the sample is placed in a magnetron sputtering chamber to prepare an oxidation alleviation layer (TiN), and a target system is obtained.

[0099] Comparative Example 3

[0100] The main difference between the present comparative example and example 3 is that the process parameters remain unchanged during the multiple spraying processes.

[0101] A method of preparing a target system, comprising the steps of:

[0102] 1) treating the surface of a copper substrate with low pressure sandblasting.

[0103] 2) ultrasonically cleaning the surface of the copper substrate with anhydrous ethanol for 10 minutes, then cleaning with deionized water, then blowing off the moisture with nitrogen, then placing it in a vacuum spraying chamber to spray a hydrogen diffusion layer matrix material, wherein the hydrogen diffusion layer matrix material is tantalum-vanadium alloy.

[0104] The spraying parameters are: powder feeding gas pressure is 5.5 psi, hydrogen flow rate is 8.5 L / min, argon flow rate is 79 L / min, and the spray gun moving rate is 900 mm / s. A 30-micron hydrogen diffusion layer is prepared.

[0105] 3) After spraying is completed, it is transferred to a dust filtering system through a transfer chamber, the surface of the sample is then cleaned, and then it is placed in a transition vacuum chamber, the surface of the sample is cleaned by blowing with argon and ultrasonic cleaning, after cleaning, it is placed in an evaporation chamber to evaporate a lithium layer, after evaporation is completed, it is placed in a magnetron sputtering chamber to prepare an oxidation alleviation layer (TiN), and a target system is obtained.

[0106] Example 4

[0107] The main difference between this embodiment and Example 1 is that the matrix material of the hydrogen diffusion layer is niobium.

[0108] A method of preparing a high-bonding-force multi-gradient target system, comprising the steps of:

[0109] 1) treating the surface of a copper substrate with low pressure sandblasting.

[0110] 2) ultrasonically cleaning the surface of the copper substrate with anhydrous ethanol for 10 minutes, then cleaning with deionized water, then blowing off the moisture with nitrogen, then placing it in a vacuum spraying chamber to spray a hydrogen diffusion layer matrix material, wherein the hydrogen diffusion layer matrix material is niobium.

[0111] For niobium, the spraying parameters for good film forming quality are: powder feeding gas pressure is 5.5 psi, hydrogen flow rate is 8 L / min, argon flow rate is 75 L / min, and the spray gun moving rate is 850 mm / s.

[0112] Specifically, a 30-micron hydrogen diffusion layer is prepared, based on the above-mentioned spraying parameters for good film forming quality of niobium, the spray gun moving rate V n The relationship with the current number of sprayed layers n is V n = 850 + A*250*(4-n), A = 1, hydrogen flow rate V g= 8 + B*0.35*(4-n), B = 1. Then, normal scan spraying is performed according to the designed thickness of the tantalum.

[0113] 3) After the spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample is transferred to a transition vacuum chamber, the surface of the sample is cleaned by argon blowing, the surface of the sample is cleaned by ultrasonic cleaning, after the cleaning is completed, the sample is placed in an evaporation chamber to evaporate a lithium layer, after the evaporation is completed, the sample is placed in a magnetron sputtering chamber to prepare an oxidation relief layer (TiN), and a target system with high bonding force and multiple gradient targets is obtained.

[0114] Comparative Example 4

[0115] The main difference between the present comparative example and Example 4 is that the process parameters are not changed during the multiple spraying processes.

[0116] A method for preparing a target system, comprising the following steps:

[0117] 1) The surface of the copper substrate is treated by low-pressure sand blasting.

[0118] 2) The surface of the copper substrate is ultrasonically cleaned with anhydrous ethanol for 10 minutes, then cleaned with deionized water, and then dried with nitrogen, and then placed in a vacuum spraying chamber to spray a hydrogen diffusion layer matrix material, wherein the hydrogen diffusion layer matrix material is vanadium.

[0119] The spraying parameters are as follows: the powder feeding gas pressure is 5.5 psi, the hydrogen flow rate is 8 L / min, the argon flow rate is 75 L / min, and the spray gun moving speed is 850 mm / s. A 30-micron hydrogen diffusion layer is prepared.

[0120] 3) After the spraying is completed, the sample is transferred to a dust filtering system through a transfer chamber, the surface of the sample is cleaned, then the sample is transferred to a transition vacuum chamber, the surface of the sample is cleaned by argon blowing, the surface of the sample is cleaned by ultrasonic cleaning, after the cleaning is completed, the sample is placed in an evaporation chamber to evaporate a lithium layer, after the evaporation is completed, the sample is placed in a magnetron sputtering chamber to prepare an oxidation relief layer (TiN), and a target system is obtained.

[0121] Performance test

[0122] The target systems prepared in Examples 1-4 and Comparative Examples 1-4 are tested for interlayer bonding force: a certain load is applied to the material surface by a diamond, and then the scratch generated is observed to evaluate the bonding force of the material. A suitable load is selected, the load is applied and the scratch characteristics are observed, and the load corresponding to the exposure of the substrate during the scratching process is taken as the critical load, and the bonding force of the material is evaluated according to the critical load, and the results are shown in Table 1:

[0123] Table 1

[0124] Experimental group hydrogen diffusion layer substrate multi-gradient hydrogen diffusion layer interlayer adhesion Example 1 tantalum yes 33N Comparative Example 1 tantalum no 20N Example 2 vanadium yes 31N Comparative Example 2 vanadium no 15N Example 3 tantalum-vanadium alloy yes 42N Comparative Example 3 tantalum-vanadium alloy no 22N Example 4 niobium yes 28N Comparative Example 4 niobium no 16N

[0125] As can be seen from the above table, after adopting the multi-gradient hydrogen diffusion layer structure, the interlayer bonding force of tantalum, vanadium and niobium is respectively increased from 20N (comparative example 1), 15N (comparative example 2) and 16N (comparative example 4) to 33N (example 1), 31N (example 2) and 28N (example 4). In addition, after adopting tantalum-vanadium alloy as the hydrogen diffusion layer, due to the interaction between different element atoms, compared with single tantalum and vanadium, the interlayer bonding force of the hydrogen diffusion layer is increased from 22N (comparative example 3) to 42N (example 3) by using the multi-gradient hydrogen diffusion layer structure.

[0126] It should be noted that the present application solves the problems of easy oxidation, poor bonding force and easy blistering of the hydrogen diffusion layer deposited by magnetron sputtering or evaporation, has the characteristics of simple operation and safe maintenance, and helps to provide a long-term stable neutron beam.

[0127] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application. Any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A method for preparing a high-adhesion multi-gradient target system, characterized in that: The high-adhesion multi-gradient target system comprises a copper substrate, a hydrogen diffusion layer arranged on the upper surface of the copper substrate, and a target material layer lithium layer arranged on the surface of the hydrogen diffusion layer; the hydrogen diffusion layer is based on a hydrogen diffusion material tantalum, and the copper is dispersed in the substrate, and the content of copper in the hydrogen diffusion layer decreases in a multi-gradient manner from bottom to top. The method for preparing the high-adhesion multi-gradient target system comprises: 1) Spraying tantalum on the surface of copper substrate 4 times to form a hydrogen diffusion layer with a multi-layer structure; wherein the moving speed V of the spraying gun for spraying the nth layer is V n =1000+A×250×(4-n), A=0.8-1.2, the unit of V n is mm / s; the hydrogen flow rate is V g =11+B×0.5×(4-n), B=0.8-1.3, the unit of V g is L / min; 2) constructing a target material layer on the surface of the hydrogen diffusion layer.

2. The method of claim 1, wherein: The surface of the target material layer is covered with an oxidation alleviation layer.

3. The production method according to claim 1 or 2, characterized by: In step 1), the copper substrate is first subjected to surface sand blasting, cleaning, and drying.

4. The method of claim 3, wherein: In step 1), after the hydrogen diffusion layer is formed, the product is treated by a dust filtration system, and then surface cleaning is performed.

5. The method of claim 2, wherein: It further comprises 3) constructing an oxidation alleviation layer on the surface of the target material layer. 6.A method for preparing a high-adhesion multi-gradient target system, characterized in that: The high-adhesion multi-gradient target system comprises a copper substrate, a hydrogen diffusion layer arranged on the upper surface of the copper substrate, and a target material layer lithium layer arranged on the surface of the hydrogen diffusion layer; the hydrogen diffusion layer is based on a hydrogen diffusion material vanadium, and the copper is dispersed in the substrate, and the content of copper in the hydrogen diffusion layer decreases in a multi-gradient manner from bottom to top. The method for preparing the high-adhesion multi-gradient target system comprises: 1) Vanadium is sprayed four times onto the surface of a copper substrate to form a multi-layered hydrogen diffusion layer; wherein, the spray gun moving speed V for spraying the nth layer is... n =700+A×250×(4-n), V n The unit is L / min; hydrogen flow rate V g =7 + B × 0.3 × (4 - n), V g The unit is L / min; 2) constructing a target material layer on the surface of the hydrogen diffusion layer.

7. The method of claim 6, wherein: The surface of the target material layer is covered with an oxidation alleviation layer.

8. The production method according to claim 6 or 7, characterized in that: In step 1), the copper substrate is first subjected to surface sand blasting, cleaning, and drying.

9. The method of claim 8, wherein: In step 1), after the hydrogen diffusion layer is formed, the product is treated by a dust filtration system, and then surface cleaning is performed.

10. The method of claim 7, wherein: It further comprises 3) constructing an oxidation alleviation layer on the surface of the target material layer. 11.A method for preparing a high-adhesion multi-gradient target system, characterized in that: The high-adhesion multi-gradient target system comprises a copper substrate, a hydrogen diffusion layer arranged on the upper surface of the copper substrate, and a target material layer lithium layer arranged on the surface of the hydrogen diffusion layer; the hydrogen diffusion layer is based on a hydrogen diffusion material tantalum-vanadium alloy, and the copper is dispersed in the substrate, and the content of copper in the hydrogen diffusion layer decreases in a multi-gradient manner from bottom to top. The method for preparing the high-adhesion multi-gradient target system comprises: 1) Spraying a tantalum-vanadium alloy on a copper substrate 4 times on the surface to form a hydrogen diffusion layer with a multi-layer structure; wherein the moving speed V n =900+A×250×(4-n), V n of the spraying gun is L / min; the hydrogen flow V g =8.5+B×0.4×(4-n), V g is L / min; 2) constructing a target material layer on the surface of the hydrogen diffusion layer.

12. The method of claim 11, wherein: The surface of the target material layer is covered with an oxidation alleviation layer.

13. The method of manufacturing according to claim 11 or 12, characterized in that: In step 1), the copper substrate is first subjected to surface sand blasting, cleaning, and drying.

14. The method of claim 13, wherein: In step 1), after the hydrogen diffusion layer is formed, the product is treated by a dust filtration system, and then surface cleaning is performed.

15. The method of claim 12, wherein: It further comprises 3) constructing an oxidation alleviation layer on the surface of the target material layer.

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